Volumn Content

The Chinese Journal of Process Engineering 2023 Vol.23 Please wait a minute... For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select Cover and Contents The Chinese Journal of Process Engineering    2023, 23 (1): 0-.   Abstract （90）      PDF （3066KB）（86）       Knowledge map    Save Related Articles | Metrics Select Exploitation and utilization of fluorite and its strategic significance Danxian ZHANG Jianhua KANG Hongjun HUANG Wenxia ZHU Ruolin WANG The Chinese Journal of Process Engineering    2023, 23 (1): 1-14.   DOI: 10.12034/j.issn.1009-606X.221373 Abstract （224）   HTML （6）    PDF （1444KB）（126）       Knowledge map    Save Fluorite, as an important non-renewable non-metallic strategic mineral resource, has been valued by many countries. With the rapid development of science and technology and the national economy, its economic value and strategic position are increasingly prominent. In recent years, the fluorine chemical industry chain has been deepening, and the demand for fluorite resources has increased sharply. Due to the limited reserves of fluorite resources, uneven distribution of resources, trade protectionism, and anti-globalization forces, the global fluorine chemical industry is highly concentrated and highly monopolized. And there are great differences in the economic development, clean and efficient utilization of fluorite resources, and intensive processing technology in different countries and regions, which have a serious impact on the supply and demand of fluorite products and consumption patterns, and intensify the contradiction between fluorite resource reserves and the development of fluorite industry. In this review, the resource reserve, main industrial structure, the consumption structure of supply and demand, and clean utilization technology aspects in detail elaborated on the economic status and the strategic significance of fluorite resources. It is proposed to ensure the global strategic layout of fluorite resources by strengthening the reorganization of fluorite resources, clean and efficient utilization, deep processing technology and equipment research and development, high-end product manufacturing, etc. To further promote the development of the fluorite industry towards the direction of fine, complex, lightweight, environmental protection and energy-saving, recycling economy fluorite chemical products application field and high-tech industry application research and development, ensure the reserve and supply of fluorite resources, achieve the optimal allocation of global fluorite resources and the healthy and sustainable development of fluorite industry. Related Articles | Metrics Select Research progress on gas-liquid two-phase flow characteristics of bubble plume Xin DONG Yinuo LIU Chen YE Jianwei ZHANG Ying FENG The Chinese Journal of Process Engineering    2023, 23 (1): 15-24.   DOI: 10.12034/j.issn.1009-606X.222021 Abstract （236）   HTML （1）    PDF （1035KB）（147）       Knowledge map    Save Bubble plume is a complex gas-liquid two-phase flow, which is widely used in industrial fields such as wastewater treatment, petroleum processing, environmental protection. The complex flow characteristics of bubble plume are very important for gas-liquid mass, momentum transfer and its industrial application. In this work, the flow characteristics of bubble plume in theoretical and experimental research are analyzed and summarized. The effects of different operating and structural parameters on the hydraulic characteristics such as gas holdup, bubble size distribution, plume width and oscillation are discussed. The simulation methods of observing and capturing the flow characteristics of bubble plume are summarized. In addition, due to the wide application of bubble plume, it is also very important to measure the bubble velocity distribution quickly and accurately. With the rapid development of digital image recognition technology, the combination of high-speed camera and digital image recognition technology provides an effective, intuitive and accurate method for bubble plume velocity. The prediction models and empirical formulas of hydraulic parameters such as gas holdup and bubble diameter are summarized, and the different applicable conditions of the models and formulas are listed. In the practical application of bubble plume, the structural morphology and flow characteristics of bubble plume change due to the complexity of environmental fluid (such as transverse flow in environmental fluid and stratification due to density and temperature difference of environmental fluid). Therefore, the research progress of gas-liquid two-phase flow characteristics of bubble plume in complex environment fluid is presented. The variation of bubble plume flow pattern and the effect of plume destratification in stratified fluid are summarized. The migration behavior and motion of plume in transverse flow environment are analyzed. Finally, the limitations of research methods and theoretical methods of gas-liquid two-phase flow characteristics of bubble plume are discussed. The multi-scale research direction of bubble plume motion law is proposed in further. Related Articles | Metrics Select Application progress of coal petrology in coking coal blending and coal blending optimization technology Yan WANG Chengwei YANG Dongying YUAN Yuhong ZHANG Sijian QU The Chinese Journal of Process Engineering    2023, 23 (1): 25-37.   DOI: 10.12034/j.issn.1009-606X.222343 Abstract （199）   HTML （1）    PDF （14196KB）（101）       Knowledge map    Save Scientific and reasonable coal blending technology was very important for the high-quality development of coking enterprises. The core of coking coal blending technology lied in the in-depth understanding of the coal quality characteristics of raw coal. The main factors affected the properties of coking coal include metamorphic degree, maceral composition and third genetic factor-fluorescence characteristics. Therefore, coal petrology was very important for the research and application of coking coal blending technology. This review discussed the development status of three coking coal blending technologies, such as experience coal blending, maceral coal blending and artificial intelligence coal blending, and summarized the overall development trend of coking coal blending technology. Combined with the author's research practice, the application status of coal petrological indexes in coking coal blending was mainly combed. While paying attention to the characteristics of maceral, it also took into account the characterization of coking coal by relevant parameters such as process indicators. In practical application, the selection and utilization of various index parameters need to comprehensively consider the parameter adaptation range and respect the true correspondence of coking coal. Based on the above content, the overall idea of associating geological factors and process indexes such as coal-forming age, producing area, caking index and gum layer index was put forward to realize the scientific and in-depth correlation between coke performance and raw coal characteristics, and to construct a new coal blending technology system of origin-process-result. By summarizing the key role of maceal in coking coal blending and its application status, the manuscript pointed out the development trend of typical coking coal blending technology, and put forward a new system of optimized coal blending technology based on maceral+fluidity, so as to establish a reliable evaluation system for coal blending and coking industry and better meet the market demand. Related Articles | Metrics Select Experimental research on heat transfer of microencapsulated phase change materials slurry containing GO in circular tube Jinli LU Xingyu CHEN Yafang HAN Yanhong SUN Zijie YIN Li WU The Chinese Journal of Process Engineering    2023, 23 (1): 38-45.   DOI: 10.12034/j.issn.1009-606X.221429 Abstract （143）   HTML （3）    PDF （1925KB）（94）       Knowledge map    Save Phase change energy storage technology can solve the problem of energy mismatch in time and space due to the latent heat absorption or release in phase change process. It has a wide application in solar energy utilization, building energy saving, waste heat recovery, and other fields. However, the phase change material has leakage problem in the process of use, so the phase change material is encapsulated and mixed with the single-phase fluid to prepare the microencapsulated phase change materials slurry (MPCMS). Furthermore, due to the high thermal conductivity properties of graphene oxide (GO), it was added to MPCM to improve the thermal conductivity of suspension prepared from GO as the substrate, thus further enhancing heat transfer. In this work, the heat transfer characteristics of pure water, 5wt% mass fraction of traditional MPCMS, 5wt% and 10wt% mass fraction of graphene oxide composite microencapsulated phase change material suspension (GO-MPCMS) were tested. And the effects of wall heat flux and Reynolds number (Re) on temperature distribution and heat transfer were analyzed and discussed. The results showed that, the temperature distribution of the tube wall and fluid presented the changing law of rised first, then stay flat and then rised again due to the influence of the phase change process. And under the same experimental conditions, the wall temperature and fluid temperature of suspension were lower than pure water. Both particle mass fraction and GO had great influence on heat transfer. With the same mass fraction (5wt%), the stable local Nusselt number (Nux) can be further increased by 8 percentage point when GO was added, and the Nux increased 20 percentage point when the particle mass fraction was increased from 5wt% to 10wt%. Compared with pure water, considering the influence of GO and microencapsulated particles, the average Nusselt number (Nu) of microencapsulated phase change material suspension can be increased by 1.0~2.0 times under the same experimental conditions. Related Articles | Metrics Select Numerical simulation optimization of flow characteristics and structure of microalgae column photobioreactor Binhua YE Fei HAN Xiangxing SHI Yonggang JIAO Qingyun ZHAO Kaiqiang ZHONG The Chinese Journal of Process Engineering    2023, 23 (1): 46-56.   DOI: 10.12034/j.issn.1009-606X.221394 Abstract （190）   HTML （1）    PDF （2177KB）（116）       Knowledge map    Save As the most potential renewable biomass energy, microalgae has significant advantages in the fields of biological carbon sequestration and biofuel production, which contributes to the realization of carbon peak and carbon neutrality goals. The cultivation efficiency of microalgae can be greatly improved by improving the performance of the aeration device of the reactor. In this work, the spherical aeration structure of the columnar photobioreactor was optimized by numerical simulation. The Euler model and k?ε model were used for the simulation and turbulence model, respectively. The changes of gas holdup, liquid velocity, turbulent kinetic energy, and the flow field in the photobioreactor under different aeration conditions were studied and analyzed. The results showed that the change in the structure of the aeration device had a great impact on the flow characteristics in the photobioreactor. When the aeration device was aerated into the reactor, the gas holdup, liquid velocity, and turbulent kinetic energy increased with the increase of the aeration rate and decreased with the increase of the aeration pore size. According to all relevant parameters, when the total aeration rate was 1400 mL/min, the number of aeration pores was 50, and the aeration pore size was 30 μm, the aerator had the best performance. At this time, the measured gas holdup was 68.6%, the liquid velocity was 0.905 m/s, and the turbulent kinetic energy was 0.149 m2/s2. The numerical simulation provided an effective way to optimize the aeration structure parameters, which benefited the photobioreactor design for microalgae cultivation and sewage treatment associated with CO2 fixation. Related Articles | Metrics Select Effect of inlet velocity on flow pattern evolution and flow distribution characteristics in discontinuous microchannels Xinsen YUAN Junfei YUAN Lin WANG He JIANG Yifei CAO The Chinese Journal of Process Engineering    2023, 23 (1): 57-66.   DOI: 10.12034/j.issn.1009-606X.222024 Abstract （166）   HTML （2）    PDF （2592KB）（107）       Knowledge map    Save The law of gas-liquid two-phase flow in microchannel is the main factor affecting the heat transfer coefficient and flow field temperature uniformity of microchannel heat exchanger. Using N2 and H2O as working fluids, the initiation, development, and stability of gas-liquid two-phase flow pattern in discontinuous and parallel rectangular microchannel heat exchangers and the uneven flow distribution in parallel channels are numerically simulated. The results show that the inlet Re of the two-phase working medium has an important influence on the evolution process and flow cycle of the flow pattern in the microchannel: when the inlet Re is 450, the gas phase working medium diffuses into the microchannel in a discrete "bulk" shape in the flow sharing cavity, and the gas phase working medium in the parallel channel gradually changes from a slug shape to a bubble shape; When the inlet Re rises to 1600, the gaseous working medium diffuses into the microchannel in a continuous "elliptical" shape in the flow sharing cavity, and the gaseous working medium in the parallel channel gradually changes from annular flow pattern to bubble flow pattern. The channel structure also affects the uniformity of flow distribution between parallel channels. The existence of discontinuous microcavity improves the uniformity of working medium mass flow distribution in the microchannel by 38.7%. By studying the pressure distribution law in the channel, it is found that the uneven distribution of static pressure in the channel is an important reason for the uneven distribution of two-phase working medium when entering the microchannel from the flow sharing cavity. By changing the inlet structure to ensure the uniform distribution of static pressure in each channel, combined with the discontinuous microcavity between continuous channels, the temperature uniformity of flow field can be better guaranteed and better heat transfer performance can be obtained. Related Articles | Metrics Select Design of gas wave ejector pressure ports and its impact on performance Yiming ZHAO Minghao LIU Haoran LI Dapeng HU The Chinese Journal of Process Engineering    2023, 23 (1): 67-77.   DOI: 10.12034/j.issn.1009-606X.221400 Abstract （160）   HTML （2）    PDF （3911KB）（52）       Knowledge map    Save Using the excess energy of a high-pressure fluid to pressurize a low-pressure fluid for achieving full utilization of pressure energy satisfies the energy-saving, low-carbon, and environmentally-friendly process engineering requirements at present. Therefore, the gas wave ejector (GWE) has a wide range of applications in many industrial processes as a device that can efficiently realize the above-mentioned comprehensive energy utilization process. Because GWE transfers energy through pressure waves formed during the connecting and closing of wave rotor passages to the pressure ports, the proper design of pressure ports distribution positions is the precondition for the device's efficient operation. The design method of pressure ports based on the wave system theory is described, and the influence mechanism of port positions on equipment performance is determined using a combination of three-dimensional numerical simulation and experiment. The results suggest that the equipment performance can reach the optimal value once the port positions satisfy the design method. However, when the port position deviates from the design values, the emergence of adverse effects such as backflow of medium-pressure gas and insufficient low-pressure gas intake result in the equipment performance declining. Due to the different impact mechanisms of different port positions on performance, the function degradation caused by port location deviation is also different. The following four conditions can lead to significant performance degradation: opening the medium-pressure port too late or closing it too early, and opening the low-pressure port too late or closing it too early. These situations should be avoided during GWE design and manufacturing. The presented research results enrich the parameters design theory of GWE, and have important guiding significance for the research and application of this equipment. Related Articles | Metrics Select Characteristics of light-assisted self-coupling algae-bacterial granular sludge treatment system Qi CHENG Chengda HE Miao ZHANG Yu XUE The Chinese Journal of Process Engineering    2023, 23 (1): 78-87.   DOI: 10.12034/j.issn.1009-606X.221349 Abstract （137）   HTML （2）    PDF （11551KB）（52）       Knowledge map    Save Self-coupled microalgae-bacterial granular sludge (algal-bacterial granular sludge, ABGS) is a new type of granular sludge. Through the symbiosis of algae and granular sludge, it not only solves the problem that the algae suspension growth is difficult to collect and treat, but also can use the photosynthesis of algae to provide oxygen for aerobic granular sludge, saving a lot of energy consumption. It provides new ideas for solving the problem of excessive energy consumption in sewage plants. Under the background that greenhouse gases have become a serious threat to the ecological environment, to explore when the light-assisted self-coupling algae-bacterial granular sludge treatment system achieves the best treatment effect, the amount of aeration required by the system. In this work, the cultivation process of the system was first described, and then the treatment effect of the system under the condition that algae oxygen supply completely replaced aeration (zero aeration) was investigated. Finally, the treatment effect of the system under the condition of appropriately increasing different aeration rates (0.2, 0.4, 0.6, 0.8 L/min) was explored. The results showed that after 12 h of treatment under zero aeration conditions, the effluent COD, total phosphorus, and total nitrogen concentrations decreased to 76.70, 1.09, and 3.52 mg/L, respectively. The concentration of each index had an obvious downward trend, and the effluent can meet the standard by continuing to increase the hydraulic retention time, but the processing cost will increase accordingly. Therefore, it was necessary to appropriately increase aeration to improve the efficiency of sewage treatment. Compared with several different aeration conditions at the level of one-tenth of the aeration required by the aerobic granular sludge treatment system, under the condition of 0.2 L/min aeration rate, the effect of each effluent index of the system reached the best. The concentrations of COD, total phosphorus, and total nitrogen were reduced to 25.6, 0.40, and 1.67 mg/L, respectively. Therefore, 0.2 L/min was the optimal aeration rate of the system, which can bring considerable effects to the energy saving and emission reduction of the sewage plant while ensuring the treatment effect. Related Articles | Metrics Select Bioreduction and biomineralization of indigenous bacteria for the remediation of uranium-contaminated groundwater Guohua WANG Ying LIU Jiali WANG Jinjing XIANG Yingjiu LIU Fa ZHAO Jinxiang LIU The Chinese Journal of Process Engineering    2023, 23 (1): 88-97.   DOI: 10.12034/j.issn.1009-606X.222013 Abstract （160）   HTML （1）    PDF （2779KB）（51）       Knowledge map    Save In recent years, microbial technology for remediation of uranium-contaminated groundwater has attracted the attention of scholars, because of its advantages of low cost, self-reproduction, no ease to cause secondary contamination, and less disturbance to the environment. The mechanisms of microbial remediation include biosorption, bioaccumulation, bioreduction, and biomineralization. Among them, bioreduction and biomineralization were two promising methods that could be utilized in situ shortly. Previous studies had shown that adding organophosphate compound to uranium-contaminated groundwater may give rise to remediation mechanisms such as bioreduction and biomineralization. To explore the coupling mechanisms of these two methods mediated by the indigenous microorganism, β-glycerol phosphate disodium salt was added in this study to stimulate the indigenous microorganism to treat neutral artificial uranium-containing groundwater. In the control group, glycerol was added to stimulate the bioreduction activity of the microbes only. The results showed that the removal rate of uranium in the experimental group was more than 98%, and the removal efficiency and effect were better than that of the control group under the same condition. After 21 days of the experiment, the scale-like precipitation on the cell surface could be observed via SEM. XRD analysis confirmed that the products were CaU(PO4)2 and Mg(UO2)2(PO4)2?10H2O, which possessed excellent resistance against reoxidation. XPS also indicated the presence of U(IV) and U(VI) in the products. Mechanism analysis showed that β-Glycerol phosphate disodium salt activated both bioreduction and biomineralization microbial community. Dysgonomonas, Propionispora, Macellibacteroides, unclassified_Rhizobiaceae and unclassified_Rhodocyclacea may be involved in the reduction of U(VI), NO3-, and SO42-, and Acinetobacter facilitated the process of biomineralization. while Methyloversatilis and unclassified_Enterobacteriaceae may take part in the reduction of U(VI)-phosphate minerals. In the early stage of the reaction, bioreduction and biomineralization were both involved in the immobilization process, and biomineralization was the main mechanism. Subsequently, the formed U(VI) precipitate was gradually reduced to U(IV) precipitate by microorganisms. This work would provide a new theoretical insight for the research on the long-term stability of bioremediation of uranium-contaminated groundwater in the future. Related Articles | Metrics Select Preparation of enhanced vanadium phosphorus oxide catalysts by alkaline earth metal-alcohols deep eutectic solvents Xingsheng WANG Zhi CHANG Liuzhu WU Manyuan ZHANG Ruirui ZHANG Ruixia LIU The Chinese Journal of Process Engineering    2023, 23 (1): 98-106.   DOI: 10.12034/j.issn.1009-606X.222040 Abstract （147）   HTML （2）    PDF （2344KB）（60）       Knowledge map    Save Vanadium phosphorus oxide (VPO) catalysts are the only industrial catalyst for the selective oxidation of n-butane. Doping with metal additives and modulation with organic additives are effective means to improve the performance of VPO catalysts. In this work, the simultaneous organo-metallic modification was achieved by adding magnesium chloride-alcohols deep eutectic solvents (MgCl2/alcohol) during the synthesis of VPO catalyst precursors. The VPO precursors and catalysts were analyzed by scanning electron microscope (SEM), BET automatic specific surface and porosity analyzer (BET), X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR), Raman spectrometer (Raman) and X-ray photoelectron spectroscopy (XPS), et al. The effect of deep eutectic solvents with different hydrogen bond donors about ethylene glycol (EG), 1-4 butanediol (BDO), and glycerol (GL) on VPO catalysts was investigated. The microscopic morphology, specific surface area, physical phase, surface properties, and crystalline phase transition temperature of VPO precursors as well as catalysts were analyzed in detail. The performance of VPO catalysts was evaluated in the fixed bed reactor for n-butane oxidation selectivity to maleic anhydride. The results showed that the introduction of deep eutectic solvent MgCl2/EG in the synthesis of VPO catalyst precursors can modulate the morphology and crystalline phase composition, thus improving the catalyst performance. The use of MgCl2/EG to modulate the preparation of VPO precursors can obtain catalysts with better dispersion, larger specific surface area, the highest total acid, and a number of active surfaces. VPO-MgCl2/EG catalysts had good dispersion, large specific surface area, a high number of active surfaces (020), enrichment of surface P atoms, and low average valence state of surface V. Furthermore, (VO)2P2O7 and VOPO4 crystalline phases synergistically improved the performance of VPO-MgCl2/EG catalysts. In conclusion, VPO-MgCl2/EG exhibited excellent catalytic performance in the reaction of n-butane oxidation selectivity to maleic anhydride, which provides a new idea for the preparation of VPO catalysts. Related Articles | Metrics Select Recycling of scrap lead paste to prepare lead powder by high efficiency electrolysis in choline chloride-ethylene glycol deep eutectic solvent Haoming HUANG Juanjian RU Yixin HUA Xiao GENG Wenwen ZHANG Mingqiang CHENG Daoxiang WANG The Chinese Journal of Process Engineering    2023, 23 (1): 107-114.   DOI: 10.12034/j.issn.1009-606X.221422 Abstract （329）   HTML （1）    PDF （2013KB）（84）       Knowledge map    Save As a clean energy source without pollution during use, lead-acid batteries have received close attention. However, lead-acid batteries contain a large amount of polluting heavy metals, and random disposal will pollute the environment and affect the ecological balance. In industry, the recovery of scrap lead paste (SLP) is usually treated by pyrotechnics, but it consumes a lot of energy and also produces pollutants such as sulfur dioxide and lead dust. In view of the existing problems, finding new recycling processes has become a research hotspot. Deep eutectic solvents (DESs) are a new generation of green solvents and have received more and more attention in recent years. Because of their good thermal stability and wide electrochemical window, DESs are widely used in the fields of metal extraction and material preparation. In this work, the recycling of scrap lead paste to prepare lead powders by electrolysis is discussed in choline chloride-ethylene glycol deep eutectic solvent (ChCl-EG DES). Firstly, the phase composition of the scrap lead paste is analyzed by XRD, and the quantitative analysis of the scrap lead paste using Jade software shows that it mainly exists in the form of lead dioxide with a small amount of lead sulfate at the same time. And then, the electrochemical behavior of lead ion in 30 g/L SLP+ChCl-EG solution is investigated by cyclic voltammetry. The phase composition and microscopic morphology of the deposit product at different temperatures are examine using XRD and SEM techniques. The experimental results show that when scrap lead paste is added, Pb(IV) can be reduced preferential to Pb(II) due to the reducibility of ChCl-EG DES. Cyclic voltammetry indicates that the reduction of scrap lead paste to metal lead is a quasi-reversible process in ChCl-EG DES. The constant voltage deposition experiment show that when the temperature rises from 323 K to 363 K, the current efficiency rises from 67.26% to 96.06% and the specific energy consumption decreases from 961.57 kWh/t to 673.28 kWh/t. XRD and SEM results demonstrate that the deposit products obtained at different temperatures are pure metallic lead powders and their microscopic morphology are mainly rod-shaped and slight acicular. Related Articles | Metrics Select Acidification process and kinetics of silicon slag from aluminum fluoride production Yijun AI Tingting LI Jupei XIA The Chinese Journal of Process Engineering    2023, 23 (1): 115-123.   DOI: 10.12034/j.issn.1009-606X.222009 Abstract （147）   HTML （1）    PDF （2830KB）（44）       Knowledge map    Save Silicon slag is a kind of solid waste produced in the reaction between fluorosilicate and aluminum hydroxide when aluminum fluoride is produced by fluorosilicate method. Aluminum fluoride is mainly used as auxiliary solvent in electrolytic aluminum industry in China and the demand is huge. Therefore, a large number of silicon slag wastes are produced. Enterprises usually store silicon slag by stockpiling, resulting in large land occupation and environmental pollution. Silicon slag contains valuable elements which can be reused is a protection of resources. In this work, a silicon residue in Yunnan Province is used as the research object. The silicon residue is acidified by concentrated sulfuric acid and the leaching rate is calculated according to the residual amount of aluminum and fluorine after acidification. A single-factor experimental scheme for the acidification process of silicon slag is designed by studying the effects of acid dosage, reaction temperature and reaction time in the acidification process of silicon slag. The phases of silicon slag, acid slag and final product are analyzed by XRD. The results show that when concentrated sulfuric acid with 1.3 times the amount of theoretical acid (23.66 g) is added, the reaction temperature is 170℃ and the reaction time is 90 min, the leaching rate of aluminum is greater than 99%, the leaching rate of fluorine is greater than 97%, and the purity of SiO2 is rapidly increased to more than 99.00%. The acidification process of silicon slag is studied by kinetic experiments. The results show that the acidification process of silicon slag conformed to the shrinking unreacted core model in the liquid-solid multiphase reaction. The activation energy of the reaction is 62.97 kJ/mol and the leaching process is controlled by chemical reactions. The proposed method provides a new idea for the utilization of silicon slag, which has the advantages of short reaction time, less water consumption and high leaching rate of valuable elements after acidification. Related Articles | Metrics Select Thermodynamic model for calculating sulfur distribution ratio between  Na 2 O-TiO 2 -SiO 2 -CaO-Al 2 O 3 -V 2 O5-MnO-MgO-FeO slags and hot metal Xuejie YIN Desheng CHEN Lina WANG Hongxin ZHAO Yulan ZHEN Tao QI Meng WANG The Chinese Journal of Process Engineering    2023, 23 (1): 124-135.   DOI: 10.12034/j.issn.1009-606X.222055 Abstract （152）   HTML （1）    PDF （2736KB）（87）       Knowledge map    Save A model for the action concentrations calculation of structural units in Na2O-TiO2-SiO2-CaO-Al2O3-V2O5-MnO-MgO-FeO slags and a thermodynamic model of the sulfur distribution ratio between slag and hot metal have been developed based on the ion-molecule coexistence theory (IMCT), and the model was verified by sodium oxide smelting experiments. The theoretical calculation results showed the composition of the main structural units and the activities of Na2O, CaO, MnO, MgO, and FeO in slag at 1200℃. The formation of compounds with a low melting point can be promoted by the addition of Na2O, meanwhile, the content of substances with high melting points decreases, which led to a decrease in the melting temperature of slag and the improvement of dynamic conditions of desulfurization reaction. Besides, the activities of Na2O and CaO increased with the increase of Na2O, thereby the activity of S2? decreased, and the desulfurization reaction between slag and hot metal can also be enhanced. The experimental results revealed that the sulfur distribution ratio between slag and hot metal improved by the increase in RN/C, which was beneficial to the deep desulfurization process of hot metal, and the sulfur can be removed to less than 0.0005wt%. The theoretical calculation results of the sulfur distribution ratio were in good agreement with the experimental results, which indicated that the sulfur distribution ratio can be well predicted by the model during the sodium oxide smelting process. The sulfur distribution ratios of basic oxide in the slag increased with the RN/C increasing and were ranked as Na2O>CaO>MnO>FeO>MgO. The IMCT was successfully applied to the investigation of the mechanism for the desulfurization reaction process between slag and hot metal in the Na2O-TiO2-SiO2-CaO-Al2O3-V2O5-MnO-MgO-FeO slags, which provided a theoretical basis for the optimization of slags in the deep desulfurization process of hot metal. Related Articles | Metrics Select Study on the mechanism of enhanced Ga electrodeposition on three-dimensional porous electrodes Ling LIU Chuchu CAI Binxin DONG The Chinese Journal of Process Engineering    2023, 23 (1): 136-143.   DOI: 10.12034/j.issn.1009-606X.222200 Abstract （166）   HTML （3）    PDF （5491KB）（50）       Knowledge map    Save Ga is usually extracted from alkaline solution with low Ga concentration by electrodeposition method in industry, where the hydrogen evolution side reaction and low mass transfer rate are the main reasons for the low current efficiency. In this work, three-dimensional porous electrodes were applied for Ga electrodeposition on account of their high surface area. The hydrogen evolution characteristics of the different electrode materials (foam metal and porous carbon) were studied. And on this basis, Ga electrodeposition behavior of each material under different electrolysis temperatures and current density was researched. The results showed that Cu foam and graphite felt (GF) had low hydrogen evolution activity, but the electrodeposition performance of Ga on the two electrodes was very different. The current efficiency (QE) of Cu foam at 40℃ and 0.1 A/cm2 was 22.5%, which was much higher than that of Cu plate (10.7%). Under the same conditions, the QE value of GF electrode was only 9.6%, which was lower than that of Cu plate and would be related to the hydrophobicity of the electrode surface. The electrodeposition behavior of Ga on electrodes with high hydrogen evolution activity (Fe foam, Ni foam, and reticulated vitreous carbon) was greatly affected by electrolysis temperature and current density. At high current density, the Fe foam electrode showed a QE value only second to that of Cu foam, and Ga electrodeposition was difficult to occur at low current density. The electrodeposition of Ga occurred only below the melting point of Ga (20℃) at Ni foam and reticulated vitreous carbon (RVC) electrodes, but it was difficult to occur at 40℃ above the melting point of Ga due to the high activity of the electrodeposited liquid Ga. Therefore, the hydrogen evolution activity of the electrode materials had a great influence on Ga electrodeposition. The key factors affecting the current efficiency of Ga electrodeposition included electrolysis temperature, current density, and hydrophilicity of the electrode surface. Related Articles | Metrics Select Rigorous modelling and energy performance evaluation for PDH reaction gas separation and hydrogen purification Xuantong LU Jin ZHAO Chun DENG The Chinese Journal of Process Engineering    2023, 23 (1): 144-153.   DOI: 10.12034/j.issn.1009-606X.221334 Abstract （359）   HTML （2）    PDF （1123KB）（130）       Knowledge map    Save Propane dehydrogenation is one of the main processes for propylene production and its reaction gas components are complex, containing products from main reactions and by-product components such as CO2 and CO from side reactions. To obtain polymer grade propylene and purified hydrogen product with a purity of more than 99.90 mol/mol, the separation process of the reaction gas of propane dehydrogenation and the recovery of hydrogen from hydrogen-rich tail gas is modeled and simulated in the Aspen software. The process includes main modules such as MEA decarburization, compressed cryogenic separation, deethanization, propylene distillation and pressure swing adsorption. The CO2 contained in the reaction gas would affect the purity of the propylene product, and it is difficult to remove in the cryogenic process. Thus the CO2 is first removed by the MEA solvent absorption. The reaction gas after decarburization and dehydration enters the deethanizer and the propylene distillation unit, and the hydrogen-rich tail gas enters the pressure swing adsorption unit for further purification. In order to reasonably utilize the energy of the propylene distillation tower, the heat pump distillation process is adopted for the energy integration. Compared with conventional distillation, the energy consumption of propylene heat pump distillation is lower. Sensitivity analysis and optimization of process parameters for hydrogen recovery by pressure swing adsorption are carried out to improve economy and energy efficiency. For the two-bed four-step pressure swing adsorption process, the effects of adsorption pressure, adsorption time and purge ratio on the purity and recovery of hydrogen products are analyzed, and the optimal operating conditions are determined. The simulation results show propylene and hydrogen products meet the requirements. The energy consumption per unit product is 267.46 kg standard oil/t propylene product and 474.44 kg standard oil/t hydrogen product. It has a certain reference significance for the simulation of the actual propane dehydrogenation reaction gas separation process and energy consumption estimation. Related Articles | Metrics Select Research and optimization on battery thermal management system with refrigerant cooling based on mini-channels Xiaojun WANG Hengyun ZHANG Xinghua HUANG Kang LI The Chinese Journal of Process Engineering    2023, 23 (1): 154-162.   DOI: 10.12034/j.issn.1009-606X.222043 Abstract （162）   HTML （1）    PDF （1781KB）（45）       Knowledge map    Save The small-scale vapor compression system based on a mini-channel heat sink was investigated in this work for battery thermal management. The single-factor experiment was carried out to determine the optimal refrigerant charge of the refrigerant cooling battery thermal management system. Based on the optimal refrigerant charge, the influence of different system parameters on thermal management performance was examined. Finally, the system problem was optimized, and the solution was proposed and verified by simulation software. Taking the coefficient of performance (COP) as the performance index, the optimum refrigerant charge of this system was 250 g, which was applied in the following experiments. Then the heating power of the battery module was fixed and the opening of the expansion valve (OEV) was adjusted to investigate the influence of OEV on cooling performance. The result showed that with the increase of OEV, the heat transfer coefficient of the mini-channel heat sink increased continuously, but the battery temperature decreased first and then increased. Thus, there was an optimal OEV to obtain the best cooling effect of the system. The heating power of the battery module was changed, and then the OEV was adjusted to make the temperature of the battery reach the minimum under different heating power conditions. The result indicated that with the increase of heating power of the battery module, the outlet dryness of the mini-channel heat sink continuously decreased, the heat transfer coefficient of the mini-channel increased, and the temperature of the battery also increased. The variation of ambient temperature was simulated by altering the indoor temperature with an air conditioner. The study showed that though the increase in ambient temperature had an impact on the cooling effect, the battery temperature can still achieve sub-ambient cooling even at the high ambient temperature of 35℃. A scheme of increasing condensation area to reduce compressor exhaust temperature was proposed, and the model was built based on AMEsim software for verification. The model analysis showed that the method of increasing the heat transfer area of the condenser can effectively reduce the exhaust temperature and improve the heat transfer effect. Related Articles | Metrics Select Cover and Contents The Chinese Journal of Process Engineering    2023, 23 (10): 0-.   Abstract （69）      PDF （5487KB）（76）       Knowledge map    Save Related Articles | Metrics Select Research process of multivesicular liposomes Xing FAN Hua YUE Xiaojun WANG The Chinese Journal of Process Engineering    2023, 23 (10): 1371-1380.   DOI: 10.12034/j.issn.1009-606X.222431 Abstract （146）   HTML （11）    PDF （2032KB）（79）       Knowledge map    Save Since 1983, multivesicular liposomes (MVLs), as a member of the liposome family, have been of interest in the biomaterials and medical fields. MVLs have multiple aqueous compartments separated by phospholipid bilayers and an internal aqueous phase of up to 90%. They also have the advantages of reducing the number of injections, extending the duration of drug action, and improving patient compliance. So far, most of the MVLs reported in the literature are above 10 μm in size and have made good progress mainly in the encapsulation of analgesic drugs. This review provides an overview of the preparation methods, characterization methods, and drug release mechanisms of MVLs that have been reported in the literature in the last decade. There are relatively several methods for preparing MVLs, including the double emulsification method, spray atomization technique, and electroforming method. Currently, the main characterization methods used for MVLs are optical/fluorescent confocal imaging, scanning electron microscopy imaging, determination of particle size distribution, entrapment efficiency, and determination of zeta potential. Because of the large volume of the internal aqueous phase of MVLs and the high hydrophilic drug encapsulation rate of the internal vesicles, the individual vesicles gradually rupture and the hydrophilic drug gradually gets released during in vitro release, with a three-phase release pattern of sustained release. This review also summarizes the current status of clinical studies and types of commercialized products. At present, the application of MVLs regarding analgesics has reached stages II-IV, and three commercialized formulations have entered the clinic with satisfactory results. Moreover, this review summarizes the current progress in applied research, mainly in the delivery of anticancer drugs, analgesic drugs, and protein peptides. Last but not least, the challenge and prospects regarding small-sized MVLs, diverse biomedical applications, and scale-up strategies are proposed. Related Articles | Metrics Select Research progress of flotation activator for complex copper oxide minerals Haoxiang WANG Peilun SHEN Jinpeng CAI Xiaodong JIA Rong PENG Dianwen LIU The Chinese Journal of Process Engineering    2023, 23 (10): 1381-1389.   DOI: 10.12034/j.issn.1009-606X.222336 Abstract （136）   HTML （10）    PDF （5380KB）（104）       Knowledge map    Save Copper is widely used in industry because of its excellent physical and chemical properties.At present, with the depletion of copper sulfide resources, the development and utilization of copper oxide resources has gradually become the focus of research. As an important source of copper metal extraction, the key to efficient recovery of copper oxide ore is the activation process. However, the existing copper oxide resources have the characteristics of high oxidation rate, complex mineral composition and easy sludge, which makes the beneficiation more difficult. The classical sulfidization-xanthate flotation method can't meet the current requirements of complex copper oxide ore resource separation. In addition, the mechanism of activator acting on mineral surface and the unclear explanation of crystal structure of activated products restrict the development of the theory and method of copper oxide ore separation to some extent. In recent years, a variety of new activators or combination activators have been reported in reference for the complex and difficult-to-beneficiated copper oxide resources. Scholars have made a deeper research and elaboration on the activation mechanism of copper oxide ore based on the existing activation theory, and put forward a variety of effective and practical new theories and methods, which have solved the problem of complex copper oxide ore beneficiation to some extent. In this review, by combing the development of activator for copper oxide ore in recent years, the application and activation mechanism of new activator and new activation method are summarized, aiming at enriching the theoretical system of efficient flotation of copper oxide ore and providing reference for production practice. Related Articles | Metrics Select Effect of conical distribution plate with slit hole on flow characteristics in fluidized reactor Tiancheng WANG Gong CHEN Dexi WANG Lixin SHAO The Chinese Journal of Process Engineering    2023, 23 (10): 1390-1400.   DOI: 10.12034/j.issn.1009-606X.222472 Abstract （134）   HTML （5）    PDF （1471KB）（100）       Knowledge map    Save Water pollution has gradually become one of the prominent problems restricting the harmonious development of urban ecosystem. At present, the development of efficient wastewater treatment technology has important practical significance to alleviate this problem. Wastewater treatment reactor is the core equipment of wastewater treatment, and the internal flow characteristics affected by its structure have an important impact on water treatment efficiency. Fluidization reactor has become a common sewage treatment equipment because of its high heat and mass transfer rate. In view of the liquid phase back mixing and uneven liquid-solid mixing still exist in fluidized reactor for wastewater treatment. Based on the mobile biofilm wastewater treatment technology and the concept of maximizing the space utilization of integrated wastewater treatment equipment, a rectangular fluidized reactor with slit hole conical distribution plate was designed. The orifice area of the distribution plate gradually increased from the center of the reactor to the outside, and the Euler-Euler multiphase flow model and RNG k-ε turbulence model were used for numerical simulation of the fluidized reactor with a conical distribution plate with slit holes. The effect of the distribution plate structure on the distribution of particles in the reactor was studied by the arrangement of the holes and the cone angle of the slit hole conical distribution plate. The results showed that the conical distribution plate with slit holes can solve the problems of liquid-phase backmixing and uneven liquid-solid mixing, form multiple ring core flows in the reactor, improve the uniformity of particle distribution, and strengthen the liquid-solid mixing. Based on the comprehensive evaluation of particle volume fraction, flow rate, and bed density standard difference, the optimal hole distribution mode of the slit conical distribution plate was determined to be perpendicular to the central axis, and the optimal fluidization effect of the reactor appeared under the cone angle of 120°. Related Articles | Metrics Select Influence of structure of swirlers on fluid field characteristics of main absorption tower Zhanyu YANG Qiling YIN Tuanliang WANG Yuge LI Wenming SONG Yufu ZHANG Yuan YAN Liping WEI The Chinese Journal of Process Engineering    2023, 23 (10): 1401-1410.   DOI: 10.12034/j.issn.1009-606X.222384 Abstract （116）   HTML （2）    PDF （17878KB）（76）       Knowledge map    Save The main absorption tower of natural gas with high hydrogen sulfur content purification needs regular welding repair due to corrosion. Before and after repair, the internal combustion integral heat treatment technology can be used to perform hydrogen-eliminating treatment and eliminate stress. The arrangement of swirlers has an important impact on air distribution and flame control during the heat treatment. In this work, the fluid field characteristics of two-stage swirler, single-stage swirler I and II in the absorption tower are simulated, respectively. The results show that there is no obvious recirculation zone above the two-stage swirler and the velocity distribution is uniform. A large tangential velocity is generated above the inner and outer swirler blades. The maximum tangential velocity is 8.33 m/s when the inlet velocity is 9.8 m/s, followed by single-stage swirler II and single-stage swirler I, 4.5 m/s and 3.12 m/s, respectively. The pressure drop in the tower corresponding to the two-stage swirler has the smallest change. These prove that the two-stage swirler can effectively generate low resistance swirling flow field. The proportion of the streamline at the bottom of the tower corresponding to the two-stage swirler changes steadily with the gas mass flow rate, and is kept at about 14%, which is consistent with the percentage of the tower bottom wall in the total surface area of the tower body. It can ensure that enough gas media return to the tower bottom and promote gas convection. The 90% residence time of two-stage swirler increases linearly with the increase of gas mass flow rate. In general, the swirling effect of the two-stage swirler is better than that of the other two swirlers, and this study provides a reference for the optimization design of swirl device of internal combustion integral heat treatment process. Related Articles | Metrics Select Liquid-liquid heterogeneous mixing characteristics of self-priming jet impeller Jing ZHANG Jiaxin YUAN Hongye LI Chengsong ZHANG Bin GONG The Chinese Journal of Process Engineering    2023, 23 (10): 1411-1420.   DOI: 10.12034/j.issn.1009-606X.223040 Abstract （110）   HTML （2）    PDF （29780KB）（79）       Knowledge map    Save As a new type of stirred device, the self-priming jet stirred tank has potential engineering application value in heterogeneous mixing enhanced process. The engineering design and industrial application of self-priming jet stirred tank were restricted by the insufficient research on the mixing characteristics. In this study, the liquid-liquid heterogeneous mixing process in self-priming jet stirred tank was investigated using numerical simulation and experiment. Water and oil were set as continuous phase and dispersed phase, respectively. Realizable k-ε turbulence model and Eulerian-Eulerian multiphase flow model were used to numerically simulate the liquid-liquid heterogeneous flow field in the self-priming jet stirred tank. The enhanced mass transfer mechanism of the self-priming jet impeller was investigated. The results showed that the dimensionless velocity on the axis of self-priming jet pipe was less affected by the stirring speed and the dispersed phase holdup. However, the single-phase flow without oil phase had lower velocity inside the self-priming jet pipe and higher velocity outside the pipe. The flow field and dispersed phase distribution in the stirred tank were significantly influenced by the inclination angle β of self-priming jet pipe. When β<0°, the self-priming flow was formed at lower end of the pipe and the jet was formed at upper end of the pipe, which was unfavourable to the radial mixing of oil and water in the stirred tank. When β=0°, the fluid velocity in pipe was close to the impeller speed, and there was no self-priming and jet flow. The impeller only produced the stirring function, which was not good to axial mixing. When β>0°, the self-priming flow was formed at upper end of the pipe and the jet was formed at lower end of the pipe. The high oil phase fluid was sucked by the self-priming jet pipe, and was jetted downward into the low oil phase fluid. The oil phase moved upward by buoyancy. For the self-priming jet impeller with β>0°, the turbulent kinetic energy at the bottom of stirred tank was effectively increased. β>0° was beneficial to eliminate the flow inhomogeneity and oil-water heterogeneous mixing process was enhanced. When β=30°, the fluid region, which dimensionless phase fraction was 0.95~1.05, accounted for 81.88% of the stirred tank volume, and the oil phase distribution was more uniform along the axial and radial directions. Related Articles | Metrics Select Comparative study on pyrolysis kinetics of different heavy oil based on distributed activation energy model Qing'an XIONG Yuming ZHANG Jiazhou LI Wei ZHANG Zhewen CHEN The Chinese Journal of Process Engineering    2023, 23 (10): 1421-1434.   DOI: 10.12034/j.issn.1009-606X.222469 Abstract （108）   HTML （1）    PDF （2207KB）（69）       Knowledge map    Save The pyrolysis behavior of Dagang slurry oil (DG-SO), Qingdao vacuum residue oil (QD-VR) and Canadian oil sand bitumen (CA-OB) were investigated by thermogravimetric mass spectrometry. The pyrolysis kinetic parameters were obtained by Friedman method, FWO method, and distributed activation energy model (DAEM), respectively. The results showed that DG-SO with relatively high content of saturates and aromatics had the highest pyrolysis reactivity, while QD-VR with relatively high content of resins and asphaltenes had the lowest pyrolysis reactivity. The releasing curves of H2, CH4, CO, and CO2 correspond to the main reaction temperature ranges of heavy oil pyrolysis. The distinctions of the shape, intensity and temperature range of the pyrolysis gases releasing curves between different types of heavy oils were mainly attributed to the corresponding composition and pyrolysis reactivity of each type of heavy oil. It was clearly found that Friedman method could gain more accuracy for description of pyrolysis process of heavy oil compared with FWO method in terms of equal conversion methods. The average activation energies (Ea) of DG-SO, QD-VR, and CA-OB were 80.15, 177.00, and 174.56 kJ/mol within the conversion range of 0.1~0.9, respectively. The one-component Gaussian DAEM could describe the whole process of SARA (saturates, aromatics, resins, asphaltenes), and their Ea were 107.78, 210.88, 268.75, and 285.44 kJ/mol, respectively. The four-component Gaussian DAEM could be used to precisely describe the whole pyrolysis process of heavy oil, and the calculated weighted average activation energies were 148.92, 205.92, and 190.37 kJ/mol, respectively. By comparing the Ea of QD-VR and its SARA components, it was found that the interaction between the SARA during the pyrolysis of heavy oil leaded to the Ea of QD-VR close to the Ea of aromatics in heavy oil. At the same time, it was found that the presence of resins and asphaltenes increased the average activation energy of saturates and aromatics, while saturates and aromatics reduced the average activation energy of resins and asphaltenes. Related Articles | Metrics Select Study on the thermal decomposition reaction behavior and kinetic characteristics of millimeter sized magnesite particles in fluidization Feng GAO Liangliang FU Dingrong BAI Guangwen XU The Chinese Journal of Process Engineering    2023, 23 (10): 1435-1445.   DOI: 10.12034/j.issn.1009-606X.222470 Abstract （106）   HTML （3）    PDF （5290KB）（74）       Knowledge map    Save Thermal decomposition is the primary step to utilizing magnesite resources. Traditionally, it has been done in the shaft or rotary-type kilns using lumpy bulk raw materials, leaving a substantial amount of small or millimeter-sized particle materials unusable. In this work, the decomposition of millimeter-scale magnesite particles using high-temperature gas-solid fluidized beds is proposed. The thermal decomposition behavior of magnesite particles with four different sizes in the range of 0.3~3 mm at different temperatures using a laboratory fluidized bed reactor of 30 mm in diameter combined with an online mass spectrometry analyzer is reported in this work. The results showed that the thermal decomposition rate of magnesite particles accelerated with the increase in bed temperature and the decrease in particle size. As the decomposition progresses, three characteristic stages can be observed. At the initial stage of decomposition corresponding to conversions of less than about 0.1, the reaction was controlled by the interfacial chemical reaction kinetics, and the apparent activation energy decreased with increasing particle size. In the middle stage of the reaction (the conversion was 0.1~0.9), the decomposition reaction obeyed the shrinking core model, and the activation energy of the decomposition reaction remained almost unchanged with the conversion for the particle of 0.46 mm in diameter but increased with the conversion for other large-sized particles. In the later stage of the thermal decomposition reaction (after the conversion was greater than 0.9), the conversion varied slowly with time, and the reaction was affected significantly by heat transfer and gas diffusion. For each of the decomposition reaction stages, the reaction mechanisms and kinetic parameters were determined based on the experimental data. This study discussed the effects of bed temperature and particle size on the thermal decomposition of magnesite particles for a better understanding of the thermal decomposition behavior of millimeter-sized magnesite particles in fluidized beds. The study provided essential data support for the development of new products for the preparation of magnesite particles in fluidized beds, serving as a critical reference for the preparation of millimeter-sized high-density dead burned magnesia at high-temperature in fluidized beds. Related Articles | Metrics Select Preparation of calcium-based composite absorbent and simultaneous removal performance of SOx and NOx from flue gas Yang LI Yang LIU Changming LI Liangliang FU Jian YU The Chinese Journal of Process Engineering    2023, 23 (10): 1446-1457.   DOI: 10.12034/j.issn.1009-606X.222344 Abstract （110）   HTML （3）    PDF （1918KB）（91）       Knowledge map    Save In order to solve the technical problems of simultaneous desulfurization and denitrification of flue gas at ultra-low temperatures (<120℃) by dry process, this work prepared several calcium-based composite absorbents by coupling different strong oxidants with lime of high specific surface area, which can realize the efficient simultaneous removal of sulfur oxides (SOx) and nitrogen oxides (NOx) from flue gas at ultra-low temperature (<120℃). The results of desulfurization and denitrification performance evaluation of calcium-based composite absorbers with different oxidant types and loadings showed that the addition of strong oxidants not only improved the desulfurization performance of Ca(OH)2 but also achieved simultaneous denitrification with Ca(OH)2. The type and amount of oxidant had a significant influence on the simultaneous desulfurization and denitrification of flue gas, and the appropriate moisture and oxygen contents of flue gas were beneficial to improve the desulfurization and denitrification efficiency. According to the characterization results of crystal structure, thermal decomposition, microstructure, and specific surface area of calcium-based composite absorbers before and after the flue gas purification reaction, it can be found that SO2 and NO are first oxidized by strong oxidants, and then react with hydrated lime to generate corresponding sulfates and nitrates, improving the desulfurization and denitrification efficiency. This study is expected to provide a new purification material and process for the upgrading of the intrinsic engineering process or purification of small industrial boilers to achieve ultra-low emission requirements. Related Articles | Metrics Select Synthesis of S-containing MAX phase Ti 2SC via the carbo-sulfidation of ilmenite concentrate Zhenqian ZHANG Sheng PANG Liangwei CONG Youpeng XU Laishi LI Yusheng WU Zhi WANG The Chinese Journal of Process Engineering    2023, 23 (10): 1458-1468.   DOI: 10.12034/j.issn.1009-606X.223041 Abstract （95）   HTML （4）    PDF （35594KB）（49）       Knowledge map    Save The MAX phase Ti2SC is a potential high-temperature structural material and precursor for titanium extraction by molten salt electrolysis due to its special structure and properties. However, the existing preparation methods all involve the use of high-value Ti powder, TiC powder, and TiS powder, since the synthesis of Ti2SC has always been thought to be through the reaction of TiC and TiS. The preparation of high-purity Ti2SC in a low-cost way is the prerequisite for its large-scale application. In this work, with ilmenite concentrate, pyrite, and graphite spherical tailings as the raw materials, high-purity Ti2SC was successfully prepared via the carbo-sulfidation of ilmenite concentrate. Since it was a new reactant system for preparing Ti2SC, the formation mechanism of Ti2SC in the FeTiO3/FeS2/C system was discussed in detail based on the results of XRD and thermodynamic calculation. A new formation mechanism that Ti3O5, the intermediate product of carbothermal reduction of FeTiO3, was directly reconstructed into Ti2SC in the molten FeS was proposed. Then, the effects of graphite proportion, sintering temperature, and holding time on the purity and morphology of products were determined by the orthogonal experiment. Ti2SC with uniform size and purity of up to 96wt% was obtained from the sample containing 27.4wt% graphite after sintering at 1400℃ for 4 h and subsequent pickling treatment continued based on the results of XRD fine-fitting data and SEM. Furthermore, to reduce the amount of acid used in the purification process, the in-situ physical separation of by-product Fe and Ti2SC was realized under 1700℃ high-temperature sintering by taking advantage of the large density difference between Ti2SC and molten Fe. The amount of acid used for purification was reduced by 72.7% according to the comparison of theoretical and actual acid consumption. The results of this study not only proposed a new pathway to synthesize Ti2SC but also provided valuable references for the industrial production of this MAX phase. Related Articles | Metrics Select Effect of carbon content on microstructure and graphite precipitation behavior of high silicon and high aluminum steel Yong WAN Dong MA Lijie TIAN Dongxu LIU Mingqi LIU Yonghong WEN The Chinese Journal of Process Engineering    2023, 23 (10): 1469-1477.   DOI: 10.12034/j.issn.1009-606X.222456 Abstract （100）   HTML （3）    PDF （45636KB）（67）       Knowledge map    Save Due to its low cost, environmental protection, and excellent machinability, graphite free-cutting steel has attracted extensive attention from metallurgical and materials scholars at home and abroad in recent years. In this work, the effects of two kinds of carbon content (0.20wt% and 0.52wt%) on the microstructure changes of 1.9wt%Si-1.1wt%Al high-silicon and high-aluminum steel during hot-rolling, quenching-tempering process and the precipitation behavior of graphite particles after tempering were studied by metallography microscope, scanning electron microscope and energy spectrum analyzer. The results showed that the microstructure of 0.20wt%C experimental steel after hot rolling→quenching→tempering was transformed into ferrite+pearlite→ferrite+"island" bainite→ferrite+graphite particle+a small amount of cementite. The microstructure of the experimental steel at 0.52wt% C after hot rolling→quenching→tempering changes to ferrite+pearlite→martensite→ferrite+graphite particles+a small amount of cementite. At the same tempering temperature, the quantity and size of graphite particles in 0.52wt% C experimental steel are larger and more precipitated in grain boundary nucleation mode than that in 0.20wt% C experimental steel. When the tempering temperature increased from 680℃ to 710℃, the density of graphite particles precipitated on the grain boundary of 0.20wt% C steel decreased from 2337/mm2 to 1710/mm2, and the average size increased from 1.50 μm to 2.27 μm. At 0.52wt% C, the density of precipitated graphite particles at the grain boundary of the experimental steel decreased from 5244/mm2 to 1938/mm2, and the average size increased from 2.36 μm to 3.45 μm. The increase of carbon content from 0.20wt% to 0.52wt% can effectively promote the nucleation and growth of graphite particles in the tempering process. Compared with the tempering at 710℃, the number of graphite particles in the tempering at 680℃ is more and the distribution is more uniform, which is more conducive to the improvement of the overall machinability of the experimental steel. Related Articles | Metrics Select Preparation of nitrogen-containing heterocyclic amphoteric resin and its separation performance toward succinic acid Junwei ZHANG Zexiao DONG Miaoxin YUAN The Chinese Journal of Process Engineering    2023, 23 (10): 1478-1487.   DOI: 10.12034/j.issn.1009-606X.222373 Abstract （105）   HTML （5）    PDF （12662KB）（52）       Knowledge map    Save In order to study the performance of an amphoteric resin with hydroxyl group and nitrogen-containing heterocycle used for the separation of succinic acid (SA), a weak acid-weak base resin, shortly called 4-VMVH resin, the copolymerization of 4-vinylpyridine with methyl acrylate and vinyl acetate, was prepared, then the physicochemical property, performance and adsorption mechanism of the resin was explored. The results indicated that more meso- and micro-pores and less macro-pore were determined inside the resin, and the adsorption of SA on the resin was an exothermic process and could be described by Freundlich model. The distribution of adsorption site on the resin was inhomogeneous, and the isosteric adsorption enthalpy of the resin decreased with increasing the fractional loading of SA. The total acid-base exchange capacity and the hydroxyl group content of the 4-VMVH01 resin were 4.607 mmol/g and 114.21 mg KOH/g and higher than that of the 2-VMVH resin. Moreover, the resolution of SA and acetic acid (AcOH) was 0.92 while the recovery rate of SA reached to 84.67% at a ratio of the column height to its diameter of 15/1 with only hot water as eluent, and the reusability of the 4-VMVH resin basically remained constant. The interaction energy between the heterocyclic N atom and the carboxyl H atom of SA was higher than that between the heterocyclic N atom and the carboxyl H atom of AcOH. The interaction energies between hydroxyl O atom and the carboxyl H atoms of SA and AcOH were respectively -26.531 kJ/mol and -25.094 kJ/mol, which belonged to the hydrogen-bonding adsorption, and therefore the retention force of SA on the 4-VMVH resin was stronger than that of AcOH. Related Articles | Metrics Select Study on the difference of enzymatic hydrolysis performance of long fibers and short fibers by straw steam explosion classification Changhong YAO Lan WANG Hongzhang CHEN The Chinese Journal of Process Engineering    2023, 23 (10): 1488-1496.   DOI: 10.12034/j.issn.1009-606X.222452 Abstract （96）   HTML （1）    PDF （9323KB）（71）       Knowledge map    Save Reducing the consumption of cellulase was the key factor to overcome the economic problem in the refining process of lignocellulose. In this study, the enzymatic hydrolysis performance of long fibers and short fibers fractionated by steam explosion classification and the possibility of using steam explosion classification to reduce the consumption of cellulase were investigated. The results showed that the enzymatic hydrolysis difficulty of short fiber was significantly lower than that of long fiber. The enzymatic hydrolysis rate of cellulose in short fiber was 1.62 times that of long fiber after 48 h of enzymatic hydrolysis at the enzyme dosage of 20 FPU/g DM. Under the enzyme dosage of 5 FPU/g DM, the enzymatic hydrolysis rate of cellulose in short fiber was 58.23% after 36 h. Under the enzyme dosage of 20 FPU/g DM, the enzymatic hydrolysis rate of cellulose in long fiber was only 51.54% after 36 h. The consumption of cellulase was reduced by 75%. The difference in enzymatic hydrolysis difficulty was due to the fact that long fiber and short fiber came from different tissues of corn straw. Due to the difference in mechanical strength, the tearing effect generated by the steam explosion crushed the husk and core into diverse particle sizes. The variety of volumes and shapes provided the basis for classification. Short fibers were mainly composed of parenchyma cells from the core, while long fibers were mainly composed of fiber cells from the husk. The crystallinity of cellulose in short fiber was lower, so the enzymatic hydrolysis difficulty was lower than that of long fiber. In addition, during the enzymatic hydrolysis of short fiber, the release of bound water was more sufficient. The liquefaction time of short fiber was shorter than that of long fiber. This indicated that mass transfer efficiency was improved during the enzymatic hydrolysis of short fiber, which was conducive to reducing the negative effect of product inhibition on enzyme activity and improving the enzymatic hydrolysis efficiency. This study provided an effective method for improving the homogeneity of lignocellulosic materials. The steam explosion classification technology effectively changed the difficulty of enzymatic hydrolysis of corn straw and saved the cost of cellulase. This was of great significance to the exploitation of lignocellulosic resources. Related Articles | Metrics Select Cover and Contents The Chinese Journal of Process Engineering    2023, 23 (11): 0-.   Abstract （63）      PDF （4360KB）（81）       Knowledge map    Save Related Articles | Metrics Select Large eddy simulation for single particle wake characteristics in concave-wall tangential jet Jing ZHANG Wenhao HOU Chenghao ZHOU Zhiguo TIAN Bin GONG The Chinese Journal of Process Engineering    2023, 23 (11): 1497-1505.   DOI: 10.12034/j.issn.1009-606X.223019 Abstract （124）   HTML （4）    PDF （6139KB）（202）       Knowledge map    Save Large eddy simulation was used to simulate the influence of spherical particles near the wall on fluid flow characteristics under the action of tangential jets on the concave-wall. The simulated wake vortex results were in good agreement with the experimental tracer image. The vortex structure and its evolution process of particle wake with particle diameter dp=4 mm and radius of curvature of concave wall R=200 mm were studied. The changes of velocity, vorticity, and streamline around the particle were investigated at Reynolds number Re=700~10 000. The results showed that the vorticity in the influence area of particles increased, the peak value of vorticity always appeared on the upstream surface of particles, and the recirculation zone behind the particles shrank significantly with the increase of Reynolds number. When Re=700, there was only one wake vortex behind the particle along the concave wall jet spanwise. When Re≥2000, there were two wake vortices behind particles along the concave wall jet spanwise, and the tangential velocity and vorticity of the fluid fluctuated periodically. The particle lift and resistance were monitored. There was the vortex shedding frequency at Strouhal number St=0.000 854 when Re=2000, and the peak value of the lift power spectrum occurred at St=0.001 52. The frequency peak corresponding to the boundary layer and wake instability was not found in the drag power spectrum when Re=10 000, and the peak of the lift power spectrum occurred at St=0.008 74. The particle wake had a great influence on the flow field. The analysis of the particle wake characteristics in the tangential jet on the concave wall was an in-depth study of the liquid-solid two phase separation mechanism. It provided the theory for the characteristics of single particle wake vortex in the process of heterogeneous separation of the tangential jet from concave wall. Related Articles | Metrics Select Experiment and DEM numerical simulation of mixing power of ultrafine powder based on similarity theory Hui CHEN Xuedong LIU Wenming LIU Weiwen ZHENG Honghong ZHANG Kaixin LÜ The Chinese Journal of Process Engineering    2023, 23 (11): 1506-1517.   DOI: 10.12034/j.issn.1009-606X.222421 Abstract （106）   HTML （2）    PDF （2454KB）（111）       Knowledge map    Save In order to study the correlation between the stirring power characteristics of ultrafine powder and the operating parameters and the calculation expression of stirring power, the problems of difficult calculation and lengthy calculation time in ultrafine powder stirring simulation were solved. The method of combining experimental research and numerical simulation was used to study the variation law of stirring power and torque of the ultrafine powder mixing process in the mechanical powder mixer. The stirring experiment of light calcium carbonate powder with an average particle size of 10.56 μm was carried out, and the operating parameters in the mechanical powder mixer, including the effects of rotational speed, blade position, and material surface height on the stirring power and torque of ultrafine powder were studied, and the expression of power calculation was obtained. Using the similar principle, the fine particles of the powder were enlarged, and the virtual experiments were carried out on the enlarged coarse particles to obtain the contact parameters. The DEM numerical simulation of the coarse particle stirring process was carried out, and the results of the simulated stirring power and torque were compared with the experimental results. The results showed that the mixing power consumption of ultrafine powder in the mechanical powder mixer was closely related to the parameters of the rotational speed, blade position, material surface height and so on. At the same time, the torque value and power value were positively correlated with rotational speed and material surface height, and negatively correlated with the blade position. The ratios of simulated torque value and power value to experimental torque value and power value were basically consistent with the particle amplification factor, which verified the accuracy of the similar principle applied to study the influence of blade position and material surface height on the stirring power characteristics. Related Articles | Metrics Select Catalytic conversion of the by-product bromoethanol in the process of CO 2 cycloaddition Ruibin GAO Lixin YI Zifeng YANG Li DONG Yifan LIU Hongfan GUO Yunong LI The Chinese Journal of Process Engineering    2023, 23 (11): 1518-1529.   DOI: 10.12034/j.issn.1009-606X.222468 Abstract （129）   HTML （0）    PDF （1824KB）（124）       Knowledge map    Save The rapid and massive accumulation of greenhouse gas CO2 in the atmosphere directly leads to global warming, ecological damage, and other environmental problems. From the perspective of renewable carbon resource utilization, CO2 is a widespread, inexpensive, and easily available C1 resource. The synthesis of ethylene carbonate employing CO2 as raw material provides a feasible industrial scheme for CO2 utilization with the atomic economy. The traditional efficient catalyst for this cycloaddition is halogen ionic liquid. However, the loss of halogen ions in the cycloaddition process leads to the additional consumption of epoxide and the generation of halogenated alcohol, thus decreasing the selectivity and yield of the main product, resulting in separation difficulty and improving equipment requirements. Therefore, it is necessary to develop an ideal catalytic system to inhibit and transform the by-product of halogenated alcohols. In this work, a series of alkalescent ionic liquids had been designed and developed to realize the in?situ conversion of bromoethanol under the condition of cycloaddition (temperature of 130℃, CO2 pressure of 3 MPa, reaction time of 3 h). The effects of different reaction conditions and different alkaline ionic liquids on the conversion of bromoethanol were investigated, including ionic liquid type, reaction temperature, different pressure environment, reaction time, etc. The reaction law of bromoethanol conversion was revealed, among which [Bu4P][HCO3] showed optimal performance. Using gas atmosphere and solvent microenvironment to regulate different reaction paths, the conversion rate of bromoethanol reached 20%~50%. After ethylene carbonate (EC) addition, the by-products with bromine-containing covalent bonds were reduced, which was more conducive to the formation of bromine ions. The conversion of halogen covalent bonds to halogen ions restored part of the catalytic activity of the cycloaddition reaction system. This was a simple versatile approach, which can realize the in?situ regulation of bromoethanol conversion pathways in the CO2 cycloaddition system, and promote the optimization of the CO2 utilization system and the circulation of halogen ions, hence possessing important scientific significance and application value. Related Articles | Metrics Select Numerical simulation of blending effectiveness of forcing mixer based on EDEM Xu GAO Jie LEI Zhanxia DI Shanping LIU Yunfeng SONG Hongming LONG The Chinese Journal of Process Engineering    2023, 23 (11): 1530-1540.   DOI: 10.12034/j.issn.1009-606X.222459 Abstract （99）   HTML （4）    PDF （36544KB）（111）       Knowledge map    Save The mixing effect of raw materials is an important factor affecting the quality and production efficiency of pellets. The forcing mixer is the core mixing equipment, and the appropriate operating parameters can make the mixed materials achieve the best mixing effect. In industry, the basic performance indicators of pellets are generally used to replace the mixing effect of materials, such as falling strength and compressive strength, resulting in long detection process, large error, and inability to visually obtain material trajectory and dispersion effect. In this study, SOLIDWORKS software is used to establish a forcing mixer model, and EDEM discrete element software is used to simulate the movement behavior of materials in the reactor. The effects of the rotating motion of the rotor, the bottom and the wall of the mixer and the filling rate of the materials on the mixing effect are studied. The results show that increasing the rotor speed can significantly improve the mixing effect, but when the rotation speed reaches ±48 r/min, the improvement of the mixing effect is not obvious. The rotation of the bottom can break through the speed threshold of the double rotor rotation, and the bottom can greatly improve the mixing effect at a lower rotation speed of +30 r/min. On the contrary, the rotation of the wall produces a stacking effect, which inhibits the dispersion of the particles, thereby reducing the mixing effect. The high filling rate is not conducive to the dispersion of materials above the rotor blade position, and the mixing effect is the best when the filling rate is 60%. Considering the enterprise pellet production and mixing equipment running performance requirements, the reasonable operating parameters are rotor rotation speed of ±30 r/min, the bottom rotation speed of +30 r/min, the wall rotation speed of 0 r/min, and filling rate of 60%. Related Articles | Metrics Select Effect of Al 2O 3 on phase transformation and structure of copper slag dilution Bo TIAN Yonggang WEI Shiwei ZHOU Bo LI The Chinese Journal of Process Engineering    2023, 23 (11): 1541-1548.   DOI: 10.12034/j.issn.1009-606X.222465 Abstract （82）   HTML （2）    PDF （4678KB）（97）       Knowledge map    Save Copper slag dilution is an important method for the sustainable development of copper metallurgy industry. As high-quality copper concentrates continue to be consumed, low-grade, high-impurity copper concentrates are gradually being utilized. As a typical low-quality copper concentrate, the content of Al2O3 in the copper slag after smelting of high-alumina copper concentrate has increased. With the change in copper slag composition, controlling the slag characteristics is critical to recover copper in the copper slag dilution process and to reduce copper losses in slag. In this work, ISASMELT copper slag was used as raw material. Analytical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM-EDS), and infrared spectroscopy (FTIR) are used to elucidate the effects of different Al2O3 contents on the phase and structure of copper slag during the copper slag dilution, as well as the effect of phase transformation and structure change on copper loss in slag. The effects of different CaO additions on the phase transformation, structure and copper loss of high-alumina copper slag are also investigated. The results show that with the increase of Al2O3 content, high melting point hercynite can be formed in the slag, and the polymerization of slag increases and the aluminosilicate structure becomes more complex. This increases the slag viscosity and the copper loss of slag. The addition of CaO in the high alumina copper slag would form high melting point hedenbergite, monticellite, and the viscosity increases. However, with the increase of CaO addition, the slag structure tends to simplify and viscosity decreases. At the CaO addition of 2wt%, the slag contains the lowest copper content of 0.78wt%. The addition of small amount of CaO can reduce the copper loss of high-alumina copper slag. Related Articles | Metrics Select Effect of low-temperature magnetization roasting on the dissolution and magnetic separation performance of high-iron bauxite Zhenxin WAN Chaoyi CHEN Junqi LI Xiaotian DUAN Dong LIANG The Chinese Journal of Process Engineering    2023, 23 (11): 1549-1557.   DOI: 10.12034/j.issn.1009-606X.223069 Abstract （97）   HTML （1）    PDF （16513KB）（75）       Knowledge map    Save Low-temperature magnetization roasting can not only improve the magnetic separation performance of bauxite but also improve the dissolution performance of bauxite. It provides a solution for the industrial utilization of high-iron bauxite. In order to realize the efficient recovery of aluminum and iron elements in high-iron bauxite, the method of "low-temperature magnetic roasting-Bayer digestion-red mud magnetic separation" is adopted to treat high-iron bauxite. The effects of roasting temperature, H2 concentration, and H2 input time on the dissolution and magnetic separation performance of high-iron bauxite were investigated. The effect of roasting on the phase transformation and microstructure of bauxite was analyzed via XRD, SEM, and BET. The results showed that diaspore dehydrated and transformed into transition Al2O3 during roasting. Thermal cracking occured in minerals, the specific surface area increased, and the leaching activity of alumina increased. The relative dissolution rate of alumina could reach 97.65% when the calcination temperature was 530℃, the concentration of H2 was 20vol%, and the time of H2 was 5 min. Magnetization roasting transformed hematite into magnetite with strong magnetism. After the magnetic separation of roasted ore, the grade of iron concentrate was 33.51wt%, and the iron recovery rate was 60.32%. The dissolution process could remove the embedding relationship between aluminum and iron elements. After the magnetic separation of red mud from roasted ore, the grade of iron concentrate reached 62.05%, and the iron recovery rate was 86.36%. The magnetic separation performance of red mud was far better than that of calcined ore. "Low-temperature magnetic roasting-Bayer digestion-red mud magnetic separation" realized the efficient separation of iron and aluminum from diaspore-type high-iron bauxite. The technical goal of removing iron and extracting aluminum had been achieved. It provided the theoretical basis and technical support for the subsequent development and utilization of high-iron bauxite. Related Articles | Metrics Select Study on the mechanism of Ni 2+ and Mg 2+ loss and enhanced separation in sulfuric acid leachate of laterite nickel ore during iron removal using neutralization process Hao JIANG Xin TENG Jun LUO Changye MANG Xinran LI Wenhao SUN The Chinese Journal of Process Engineering    2023, 23 (11): 1558-1567.   DOI: 10.12034/j.issn.1009-606X.223055 Abstract （99）   HTML （2）    PDF （8323KB）（79）       Knowledge map    Save Neutralization precipitation process is often used to remove impurities such as iron, aluminum and chromium from the nickel laterite acid leach solution, however, it accompanied with the loss of nickel and magnesium metal ions. The precipitation behaviors of Ni2+ and Mg2+ ions in nickel laterite acid leach solution during the neutralization precipitation iron removal process was deeply discussed in this work. Furthermore, a novel precipitation mechanism of Ni2+ and Mg2+ with SO42- during the neutralization precipitation iron removal process was proposed. The results showed that under the condition of fixed Ni2+ and Mg2+ concentrations in simulated leachate, the loss rate of Ni2+ and Mg2+ during neutralization and precipitation respectively were 9.13%~23.23% and 9.79%~15.68% with the increase of Fe3+ concentration in simulated leachate. Under the condition of fixed Fe3+ concentrations, the loss rate of Ni2+ and Mg2+ decreased with the increase of the concentration of Ni2+ and Mg2+. According to the results of solution chemical calculation and the characterization of iron hydroxide precipitation by infrared spectroscopy and scanning electron microscopy, both SO42- ions and Fe(OH)3 colloids could co-precipitate in the form of monovalent or binary complex during the neutralization process, in which the lone pair electrons of SO42- in the monovalent complexes bond with Ni2+ and Mg2+ and adsorb, resulting Ni2+ and Mg2+ in the leachate were co-adsorbed with SO42- by Fe(OH)3 colloid and the loss was caused. In addition, it was found that the surfactant such as cetyl trimethylammonium bromide (CTAB), polyethylene glycol (PEG), sodium dodecyl benzenesulfonatecan (SDBS) was added during the neutralization precipitation process can effectively compete for adsorption with neutralizing precipitated products or impede the combination of SO〖_4^(2-)〗 with Ni2+ and Mg2+ ions, which could enhance the selective precipitation of Fe3+ ions during neutralization process. When the dosage of three surfactants was 2×10-5 mol/L, the retention rates of Ni2+ in the process of neutralization and precipitation of iron could reach about 95%, and Mg2+ could reach 100%. Related Articles | Metrics Select Removal of low-concentration toluene with multi-needle corona discharge coupling Ag/TiO 2 nanocatalyst system Yan YAN Bin ZHU Li XU Yimin ZHU The Chinese Journal of Process Engineering    2023, 23 (11): 1568-1576.   DOI: 10.12034/j.issn.1009-606X.223021 Abstract （79）   HTML （0）    PDF （2631KB）（78）       Knowledge map    Save A plasma-catalytic system was constructed by coupling multi-needle corona discharge with Ag/TiO2 nanocatalyst. The discharge characteristics of the plasma-catalytic system were diagnosed, and the characterization of the Ag/TiO2 nanocatalyst was also performed. The multi-needle corona discharge coupling Ag/TiO2 nanocatalyst system was applied to remove low-concentration toluene from the air. The secondary pollutant of ozone was monitored during toluene removal. Further, the mechanism of toluene removal and suppressed ozone generation during toluene removal was disclosed. It was found that the plasma diffused in the whole discharge region when the discharge voltage was higher than 7.0 kV. The presence of Ag/TiO2 nanocatalyst showed no obvious influence on the discharge. These features facilitated the high plasma density and intimate interaction between reactants, plasma, and Ag/TiO2 nanocatalysts. Ag particles in the Ag/TiO2 nanocatalyst possessed an average size of 6.5 nm, which created large numbers of highly active Ag-TiO2 interfacial sites and endowed Ag/TiO2 nanocatalyst with strong absorption ability for UV-visible light. At a voltage of 7.5 kV, the multi-needle corona discharge obtained toluene conversion and CO2 selectivity of 21% and 7%, respectively. Coupling of multi-needle corona discharge and Ag/TiO2 nanocatalyst made toluene conversion and CO2 selectivity increased to 83% and 61%, respectively. The concentration of ozone in the plasma-catalytic system was 0.02 mg/m3, which had a remarkable decrease compared with the pure discharge (5.12 mg/m3). The performance of the multi-needle corona discharge coupling Ag/TiO2 nanocatalyst system was attributed to the synergetic effect between the light field, electrical field, and catalytic sites, which could modulate the conversion path of intermediates and extend the avenues of toluene removal. This study would provide an important reference for the application and development of plasma-catalysis techniques in indoor air purification. Related Articles | Metrics Select Experimental verification of a small medical waste decoupling incineration treatment system Xinhua LIU Jian HAN Jiangping HAO Rong LI Hongming XIAN Shanwei HU Nan ZHANG Hao LAN The Chinese Journal of Process Engineering    2023, 23 (11): 1577-1586.   DOI: 10.12034/j.issn.1009-606X.223067 Abstract （71）   HTML （2）    PDF （3996KB）（96）       Knowledge map    Save Due to the potential negative impact on human health and environmental safety of medical waste, it is of great significance for numerous small and medium medical institutions far away from cities or inland to dispose of a small amount of medical waste harmlessly on the spot. However, there still lacks small-scale packaged technology for the clean and high-efficiency treatment of medical waste, so it is difficult to implement the onsite hazard-free reduction disposal of medical waste. In view of some combustion and flue gas treatment problems confronted in the harmless onsite disposal of a small amount of medical waste, this work designed and experimentally verified an integrated decoupling incineration treatment system suitable for the decentralized disposal of medical waste by using the so-called decoupling combustion technology. The results showed that the decoupling incinerator could facilitate the high-efficiency and stable combustion of medical waste and the suppression of emissions of nitrogen oxides (NOx) and dioxins (PCDD/Fs). The small flue gas purification facility based on two-stage wet desulphurization technology enabled rapid cooling of flue gas to avoid the secondary generation of dioxins and simultaneous removal of acidic substances and particulate matter (PM). Treating typical medical waste blending in the small integrated decoupling incineration system, the emissions of NOx, SO2, PM, CO, and PCDD/Fs could be lower than 123, 1.8, 38, 53 mg/m3, and 0.31 ng I-TEQ/m3 on the 11vol% O2 basis, respectively. The newly-developed small medical waste incineration treatment system featured a compact configuration structure and high purification efficiency because of its integrated design of decoupling incinerator and purification equipment so that it can meet the need for onsite clean disposal of daily medical waste in the decentralized medical institutions. Related Articles | Metrics page Page 1 of 5 Total 178 records First page Prev page Next page Last page