Table of Content

28 August 2023, Volume 23 Issue 8

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Contents

Cover and Contents

The Chinese Journal of Process Engineering. 2023, 23(8):  0. 

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Development of New Energy Industry

Review of additives for electrolyte of sodium-ion battery

Yuyue GUO Xiaoying ZHAI Ningbo ZHANG

The Chinese Journal of Process Engineering. 2023, 23(8):  1089-1101.  DOI: 10.12034/j.issn.1009-606X.223104

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With the upsurge of the energy revolution, secondary battery as a new way of energy storage has been widely concerned owing to their efficient energy conversion. As we all know, lithium-ion batteries (LIBs) have high operating voltage and high energy density, they can be used in various application scenarios, such as electrical vehicles (EV), portable electronic devices, and large-scale energy storage systems. However, due to the shortage of lithium resources and rising prices of raw materials, many battery companies are observed to undergo cost pressure and bankruptcy risk. Given this, sodium-ion batteries (SIBs) work similarly to lithium-ion batteries, but they have great advantages in terms of resource reserve, low cost, low temperature, rate performance, and safety, thus have received strong attention from researchers and engineers. In the sodium-ion battery system, it is also composed of the positive electrode, negative electrode, electrolyte, separator, and other key components. The electrolyte, as the intermediate bridge connecting the positive and negative electrode material system, plays a vital role to undertake the transport of sodium ions, which mainly consists of organic solvent, sodium salt, and additives. The introduction of a small number of functional additives can significantly improve the overall performance of the battery because it constructs a solid electrolyte interface (SEI) between electrolyte and electrode. Different kinds of additives can exhibit specific properties to meet different conditions. This review focuses on the use of electrolyte additives, including unsaturated carbonates, sulfur compounds, phosphorus compounds, silicon compounds, inorganic sodium salts, and other types of components. Meanwhile, the research progress and related mechanisms of this addition agent in the electrolyte of sodium-ion batteries in recent years were summarized as a reference for subsequent research. Finally, the future study of electrolyte additives prospects from the science idea and practical application, for example, density functional theory, AI for science, and in-situ analysis method for SIBs.

Research progress of thermal management technology for lithium-ion batteries

Jiaxin LI Pengzhao LI Miao WANG Chun CHEN Liangyu YAN Yue GAO Shengchen YANG Manman CHEN Cai ZHAO Jing MAO

The Chinese Journal of Process Engineering. 2023, 23(8):  1102-1117.  DOI: 10.12034/j.issn.1009-606X.223094

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Efficient battery thermal management technology is critical to the safe operation, long cycle life, and overall cost reduction of lithium-ion batteries and is important in promoting the large-scale application of lithium-ion batteries. In this review, several mainstream battery thermal management technologies are discussed in detail, including air cooling, liquid cooling, new phase change material cooling, and thermoelectric cooling technology. The battery heat generation model is briefly described. Finally, the development direction of battery cooling technology is prospected. Air cooling technology is simple in structure, but it is difficult to ensure temperature uniformity of the cells within the battery pack and is not suitable for cooling large lithium-ion battery packs, but is more suitable for small flying electric devices and low-end electric vehicles. Cooling plate liquid cooling technology is more effective, but there is a risk of coolant leakage and the temperature uniformity needs to be further improved. Immersion liquid cooling technology offers significant cooling and temperature uniformity but is expensive and is likely to be used more often in the future in energy storage plants with high cooling requirements, while for most lithium-ion electric vehicles the lower-cost cooling plate liquid cooling technology is more suitable. Phase change material cooling and thermoelectric cooling technologies without moving parts have achieved initial commercial application in electronic equipment and small power plants, but the cooling efficiency is low and needs further refinement. It is worth noting that it is critical to choose the right cooling technology for the user's needs. While there is no perfect cooling solution, a combination of cooling technologies can be used to meet the thermal management needs of a wider range of application scenarios.

Research and industrialization of conductive additive technology in the field of new energy batteries

Peiling YUAN Xingxing DING Peng GUO Caili ZHANG Rui HU

The Chinese Journal of Process Engineering. 2023, 23(8):  1118-1130.  DOI: 10.12034/j.issn.1009-606X.223115

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Secondary batteries have been widely developed and used in various fields, such as large-scale energy storage, portable electronic devices, and electric vehicles. Conductive additives, as an important component of lithium-ion batteries, could increase and maintain the electronic conductivity of the electrodes by constructing a conductive network, which will effectively improve the electrochemical performance of batteries. Although conductive additives account for a relatively small proportion of the cost of lithium batteries (around 2%), compared to the trillion level lithium battery industry, conductive additives have also become a trillion level industry. At present, the mainstream conductive additives are carbon black, conductive graphite, vapor grown carbon fiber (VGCF), carbon nanotubes, and graphene. They are ideal conductive additives for lithium-ion batteries because of superior properties such as low weight, high chemical inertness, and high specific surface area. Among them, carbon black, conductive graphite, and VGCF are traditional conductive additive materials that form point and line contact conductive networks between active materials; carbon nanotubes and graphene belong to new conductive additive materials, which respectively form wire and surface contact conductive networks between active materials. Compared to a single conductive agent, composite conductive agents create synergistic effects between different conductive agents, thus exhibiting better performance. Therefore, we believe that the new conductive agent has a highly unified relationship with traditional conductive agents. Taking into account both cost and performance, the future conductive agent system will gradually shift from singularity to multiple composites. In addition, China's conductive agents have long relied on imports. In recent years, some excellent enterprises have gradually broken through process barriers in preparation methods and dispersion technologies, accelerating the process of localization. This article will discuss the related work of using carbon nanomaterials as conductive additives in the field of batteries and improving their electrochemical performance. Then, further discuss the industrialization status and prospects of conductive additives.

Study on aluminum anode with different Ti addition for kW-grade aluminum-air batteries

Cong XU Xinyue FANG Min KONG Ruizhi WANG Jun ZHANG Guangxi LU Junhua HU Shaokang GUAN

The Chinese Journal of Process Engineering. 2023, 23(8):  1131-1136.  DOI: 10.12034/j.issn.1009-606X.223107

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With the development of science and technology, modern industry and social development rely more and more on electric energy, advanced and efficient energy conversion technology is the key to the development, of new high-power fuel batteries (such as aluminum-air batteries) because of its high energy density (theoretical energy density 8100 Wh/kg), abundant storage capacity, low production cost, environmental protection, and non-toxic advantages and so on favored by many scholars. However, there are some problems against the application of aluminum anodes, such as high overpotential caused by the attached passivation layer on the surface and high self-corrosion rate in alkaline electrolytes. To address these challenges, many researchers are committed to improving anode performance through microalloying. In this work, the effects of different Ti contents (0.03wt%, 0.05wt%, 0.08wt%, and 0.10wt%) on the microstructure, corrosion behavior, electrochemical behavior, and discharge behavior of Al-Mg-In anode materials for kilowatt-class aluminum-air batteries were investigated systematically. The results show that with the increase of Ti content, the fibrous grains in the Al-Mg-In anode gradually refine, the grain organization gradually becomes uniform, and the increase of the number of grain boundaries can provide more reaction area for the air batteries, and the discharge activity of the anode material will increase with more discharge reaction channels, which will help to increase the working voltage of the aluminum anode. However, when the Ti addition exceeds 0.05wt%, the number of second phase particles in the Al-Mg-In anode sheet will increase, and a "primary battery" will be formed between the second phase and the substrate, which will accelerate the corrosion of the alloy and the local dissolution of grain boundaries, resulting in the decrease of corrosion resistance and discharge performance of the alloy. Therefore, the Al-Mg-In alloy with 0.05wt% Ti has the best corrosion resistance and battery discharge performance, indicating that the appropriate amount of Ti can optimize the performance of aluminum-air batteries.

Review

Research progress of core monomer separation and purification technology for bio-based materials

Kun WANG Xiuling JI Kun LIN Yuhong HUANG

The Chinese Journal of Process Engineering. 2023, 23(8):  1137-1149.  DOI: 10.12034/j.issn.1009-606X.222314

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The production of petrochemical-based materials consumes large amounts of non-renewable resources and cause a certain degree of pollution to the environment. The performance of bio-based materials produced by renewable resources can be comparable to that of petrochemical based materials, which is in line with the development concept of green, low-carbon and environmental protection, and provides strong technical support for the realization of the goal of carbon peaking and carbon neutrality. In recent years, with the domestic and international policies tilted to the bio-based materials industry, bio-based materials have become a new material for domestic and international development, providing a good opportunity for the development of bio-based materials industry. The core monomer of bio-based materials produced by biological method has the advantages of mild production conditions, low price, and green environmental protection. But the complex composition within the fermentation broth as well as the low concentration of monomers and the difficulty of separation have seriously restricted the development of the whole industry of bio-based materials. The production of bio-based materials requires high-purity monomers, and a small amount of impurities affect the appearance and performance of bio-based materials. The existing research and application of separation of core monomers of bio-based materials has developed the process of obtaining high purity separation and purification of core monomers of bio-based materials by taking full advantage of chemical separation technology. This review briefly introduces the current status of the production of bio-based materials, reviews the research progress of several widely used separation and purification technologies for core monomers of bio-based materials in recent years, analyzes the advantages and disadvantages of current separation technologies. Finally providing an outlook on the development trend of separation and purification technologies for core monomers of bio-based materials.

Research progress on depression mechanism of chitosan and its derivatives during flotation

Pengpeng ZHANG Cheng YANG Hongming LONG Xiangpeng GAO Mingyang LI

The Chinese Journal of Process Engineering. 2023, 23(8):  1150-1160.  DOI: 10.12034/j.issn.1009-606X.222217

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As one of the most effective methods for low-grade ore separation, flotation has the advantages of obvious sorting effect on fine-grained ores and high separation efficiency. It is crucial to use reasonable and eco-friendly depressants in order to improve the flotation separation effect. As a new type of organic depressant, chitosan is widely used in mineral flotation due to its outstanding physical and chemical properties, environmental protection and easy preparation. Many chitosan derivatives also have excellent depression capabilities. In this work, the research progress of chitosan and its derivatives in flotation experiments of various minerals in recent years is reviewed. Firstly, the main adsorption methods of chitosan and its various novel derivatives as flotation depressants on mineral surfaces are introduced. Then, the depression mechanism and the main factors affecting the depression effect are summarized. Discussion and potential future research directions of chitosan derivatives depressants are also included. Although the research on chitosan and its derivative depressants is becoming more and more mature, the main depression mechanism is still not detailed enough. With the advancement of various detection methods, how to improve the depression effect and further clarify the related groups and main depression mechanisms will be a major focus of future research on chitosan derivatives depressants.

Research progress of metal-organic framework material modified MFC air cathode to improve the electric performance

Jinrong LU Linde REN Hua LIU

The Chinese Journal of Process Engineering. 2023, 23(8):  1161-1172.  DOI: 10.12034/j.issn.1009-606X.222339

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Microbial fuel cell (MFC), a new type of clean energy production equipment, can generate electricity while decomposing organic matter in wastewater. Facing the emergence of energy crisis, the reasonably designed MFC equipment can alleviate the current energy crisis, the generation of this new energy is green and sustainable. The conversion rate of energy is an important factor that affect the wide application of MFC, so improving the power production performance of MFC has attracted a lot of attention from scholars. Air-cathode MFC is an MFC configuration that uses oxygen as an electron acceptor to complete current transfer, that is the most promising type of MFC, but it is also accompanied by the problem of low activity of cathodic oxygen reduction reaction (ORR). Precious metal catalysts have never been able to meet the needs of practical applications, and cost-effective metal-organic framework (MOF) materials have been studied as ORR catalysts for many years. Therefore, MOF materials suitable for MFC air-cathode can be prepared as cathode catalysts to improve their power production performance through rational design. This work reviews the recent research progress of MOF and its derivatives as catalysts for modifying MFC air-cathode to improve their electricity production performance. The principles of MFC and the natural advantages of MOF materials as ORR electrocatalysts are introduced, and the latest applications of three types of materials, namely, simple MOF, MOF composites, and MOF derivatives, as MFC air-cathode catalysts are highlighted, leading to a variety of different research directions of MOF and its derivatives as MFC air-cathode catalysts. Finally, the challenges and future prospects of MOF and its derivatives in modifying MFC air-cathode to improve their power production performance are elucidated. The intention is to summarize the shortcomings exposed by MOF in modifying MFC air-cathode and provide new research ideas for the future application of MOF materials in MFC cathodes in order to promote the practical application of MFC.

Research Paper

Liquid-liquid dispersion characteristics in stirred tanks with different baffles

Hualong QIN Mengke GUO Xiangyang GONG Yiqun TIAN Chunxue PENG Qinghua ZHANG Chao YANG

The Chinese Journal of Process Engineering. 2023, 23(8):  1173-1179.  DOI: 10.12034/j.issn.1009-606X.222397

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Baffle is an important part of the stirred tank, and it can effectively improve the flow state of fluid and the effective utilization of power in the stirred tank. In order to reduce power consumption and improve mixing performance of the stirred tank, a zigzag punched baffle has been developed in our previous work. However, its performance in a liquid-liquid stirred tank has not been performed. With taking water and kerosene as a research system, the liquid-liquid dispersion characteristics in stirred tanks with standard baffles (SB), standard punched baffles (SPB), and zigzag punched baffles (ZPB) were studied by numerical simulation. The results showed that due to the formation of the impinging steam, the zigzag punched baffle can effectively reduce the dead zone behind the baffle in the stirred tank. With an increase of stirring speed, the stirring power consumption of the three different baffled stirred tanks all gradually increased, meanwhile the kerosene droplet diameter decreased. At the same stirring speed, the power consumption of the SPB stirred tank was almost the same as that of the SB stirred tank, while the gap between ZPB and SB stirred tanks was growing with the increase of stirring speed. The droplet diameter in the stirred tank with zigzag baffle was much smaller than that of the tanks with standard baffle and the standard punched baffle at the same stirring speed. With the increase of stirring speed, the difference between the droplet diameter of ZPB and SPB and that of SB increased first and then decreased. When the stirring speed is 400 r/min, the difference was the largest. At this time, compared with the SB stirred tank, the droplet diameter of kerosene in the SPB and ZPB stirred tanks decreased by 18.16% and 36.87%, respectively.

Experiment research of influence of low concentration surfactant on particle deposition morphology of evaporated sessile drop

Chuyue WU Yongqing HE Xi CHEN

The Chinese Journal of Process Engineering. 2023, 23(8):  1180-1189.  DOI: 10.12034/j.issn.1009-606X.222355

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Regulation of the deposition morphology after sessile drop evaporation has numerous applications and potential benefits. The drop evaporation of particle suspension with polystyrene particles and sodium dodecyl sulfate (SDS) was experimentally observed and analyzed. The effect of SDS with a concentration of 0wt%~1wt% on the evaporation process of polystyrene particle suspension and the deposition morphology after evaporation was studied. The results demonstrated that the droplet contact angle decreased nonlinearly with the increase of SDS concentration. When SDS was added, spontaneous spreading driven by surface-tension gradient occurred. It was found that the maximum spread coefficient was positively correlated with SDS concentration. The spreading process took only 1/5~1/3 of the total evaporation process time. The gray level co-occurrence matrix (GLCM) was used to analyze the effect of adding SDS on the deposition morphology inside the coffee ring. The SDS could not only regulate the ring width, but also reduce the aggregation of particles in the middle of a deposition, and the deposition was more uniform (the most obvious when the concentration of SDS was 0wt% compared with 0.1wt%). Marangoni flow in the droplet would become more ferocious as SDS concentration rose, and the ring grew broader. There was an upper limit for SDS to regulate the ring width of the annular deposition, as the annular deposition was not readily apparent when the concentration of SDS was higher than 0.75wt%. Most of the particles were uniformly distributed throughout the entire deposition area, forming a disc-like deposition. The maximum percentage of annular deposition area for particles were 58.6% for diameter of 5.7 μm and 44.6% for diameter of 10 μm. It demonstrated that SDS affected the deposition pattern of particles of various sizes in distinct ways.

Characteristics of solid velocity distribution in gas-solid concurrent/counter-current intermittent moving bed

Zhifeng ZHAO Qifan JIA Ruojin WANG Dewu WANG Shaofeng ZHANG

The Chinese Journal of Process Engineering. 2023, 23(8):  1190-1198.  DOI: 10.12034/j.issn.1009-606X.222423

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The particle tracer method is applied to investigate both the solid flow state and the solid velocity distribution under different superficial gas velocities and times in the gas-solid concurrent/counter-current intermittent moving bed. The quantitative analysis is made and the calculation formula of the solid velocity is also established. The results show that, an approximate V-shaped distribution is presented in the particle tracer layers, which indicates that the horizontal distribution of the solid velocity is in the form of the "slow-fast-slow". Moreover, the variation of the solid velocity distribution is more obvious with the passage of time. Different from the gravity condition, the interaction between the gas and the solid phases is more complex under both the concurrent and the counter-current conditions. At the same time, with increasing superficial gas velocity, the variation range of the solid velocity distribution increases in the concurrent moving bed; while it decreases in the counter-current moving bed. Besides, at the same height of the particle layers, with increasing superficial gas velocity, the width of the flow area increases in the concurrent moving bed, and both the inhomogeneity index of the flow time and the percentage of solid flow dead zone decrease, which indicates a more uniform solid velocity distribution appears under concurrent condition. However, it is opposite in the counter-current moving bed. Based on the widely used solid velocity model of particle kinematic model (PKM) in the silo, with the introduction of both the Reynolds number Re and the Stehar number St, the calculation formula of the solid velocity is established under both the concurrent and the counter-current conditions in this work. It is anticipated to provide a reference for the operation and design of the gas-solid concurrent/counter-current moving bed.

Synergistic extraction for cesium(I) by 1,3-diisopropoxy calix[4]arene crown-6 and 4-tert-butyl-2-(α-methylbenzyl) phenol in low alkalinity conditions

Huifang XING Lu WANG Liangrong YANG Meng RONG Gang YE Huizhou LIU

The Chinese Journal of Process Engineering. 2023, 23(8):  1199-1207.  DOI: 10.12034/j.issn.1009-606X.222383

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Cesium (Cs) is widely applicated in the production of aeronautics, electronics, pharmacy, and catalysts. With the increasing demands for cesium resources by emerging technologies and the reduction of cesium ore, it is imperative to develop new cesium resources such as salt lake, geothermal, and oil & gas produced brine. Solvent extraction is a promising method for its advantages of continuous operation, simple equipment, and high throughout. The traditional extractants represented by calixarene crown ethers, and substituted phenols exhibit high Cs selectivity. 1,3-diisopropoxy calix[4]arene crown-6 (BPC6) is a typical calix[4]crowns which can coordinate with Cs+ ion with high affinity. Meanwhile, 4-tert-butyl-2-(α-methylbenzyl) phenol (t-BAMBP) is a kind of substituted phenol that selectively extracts Cs+ ions through ion exchange. However, both of them are limited for cesium isolation from brine due to the need for strong acid (1~4 mol/L HNO3) or basic (almost 1 mol/L NaOH) conditions. It is necessary to explore new extraction systems which apply in relatively mild conditions for liquid Cs resource applications. In this work, BPC6 and the t-BAMBP mixture were developed as a novel coordination-cation exchange coupling synergistic extraction system for the recovery of Cs(I) in weakly alkaline conditions of 30 mmol/L NaOH. The synergistic coefficient was calculated as 89.5 when the concentrations of BPC6 and t-BAMBP were 10 and 200 mmol/L, respectively. The synergistic extraction mechanism was discussed, and the thermodynamic parameters and equilibrium constants of the extraction reaction have been calculated. Moreover, stripping with only 10 mmol/L HCl produced a stripping efficiency of 84.1%. Besides, the effect of temperature on the stripping was investigated and 81.3% stripping efficiency can be achieved by heating at 313 K without any acidity solution. On this basis, a novel synergistic extraction and stripping system was established with the advantages that both the extraction and stripping can be carried out under mild conditions and obtained high potential in Cs(I) recovery of brine for its low acid-base consumption.

Enzyme-enhanced mixed anaerobic digestion of excess sludge and kitchen waste leachate

Tongzhan XUE Xin SUN Weihua LI Xiaoji LIU Kun WANG Xiangyu YAN Houyun YANG

The Chinese Journal of Process Engineering. 2023, 23(8):  1208-1219.  DOI: 10.12034/j.issn.1009-606X.222311

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In order to study the effect of hydrolase on the gas production performance of mixed anaerobic digestion of residual sludge and kitchen waste leachate, the residual sludge and kitchen waste leachate from urban sewage treatment plants were used as substrates, and the mixing ratio was 1:1 and 2:1, and protease and cellulase were added in the ratio of 1:1, 1:2, and 2:1 (total enzyme addition amount: 60 mg/g TS) to the mixed solution, and mixed anaerobic digestion at a temperature of (38±0.5)℃. The results showed that the gas production performance and disposal effect was the best when protease and cellulase were added in 1:1 in the 2:1 mixed anaerobic digestion system of residual sludge and kitchen waste leachate. Its daily methane production peak is 60.15 mL/g VS, which is 1.84 times higher than that of sludge digestion alone, and 70.49% higher than that of the same substrate without enzymes; the total methane production was 296.17 mL/g VS, which was 75.99% higher than that of sludge digestion alone, and 62.87% higher than that of the same substrate without enzymes; the removal rates of total solid (TS) and volatile solid (VS) were 41.43% and 67.32%, respectively, which were 14.74 and 27.89 percentage point higher than that of sludge digestion alone, and 8.34 and 21.99 percentage point higher than that of the mixed solution without enzymes in the same group, and there was no ammonia inhibition and VFAs accumulation during the digestion process. Using three-dimensional fluorescence spectroscopy combined with parallel factor analysis, it was found that the fluorescent substances present in the mixed anaerobic digestion process were mainly protein-like, fulvic-like, and humic-like. There were significant differences in protein fluorescence intensity in different time periods of digestion. This change was more pronounced in the enzyme-added experimental group. The results of this study can provide a reference for the reduction and recycling of excess sludge and kitchen waste.

Evaluation and analysis of ionic liquid-containing wastewater by a novel nanofiltration-flash evaporation coupled recovery process

Dian NIU Jianguo QIAN Jian CHEN Guoxiong ZHAN

The Chinese Journal of Process Engineering. 2023, 23(8):  1220-1230.  DOI: 10.12034/j.issn.1009-606X.223168

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The highly efficient and low-cost recovery of ionic liquid from the solution remains an issue to realize the reuse of ionic liquid. This work proposes the coupling process combining nanofiltration and vacuum flash evaporation for recovery of ionic liquid in solution. The lower concentration of ionic liquid aqueous solution is concentrated through nanofiltration technology, and then the higher concentration of ionic liquid aqueous solution is treated by the vacuum flash evaporation process to obtain the pure ionic liquid and realize the efficient separation and recovery of ionic liquid. 1-methyl-3-octylimidazolium tetrafluoroborate ([C8Mim][BF4]) and 1-ethyl-3-methylimidazolium tetrafluoroborate ([C2Mim][BF4]) were used as model compounds to explore the recovery effect of the coupling technology by process simulation. Based on the literature reported data on the previous researches, the main physical properties of ionic liquid and ionic liquid-water thermodynamic models were constructed by the regression method. A model of the coupled process of the separation and recovery technology for ionic liquid was established by Aspen Plus simulation software. The influences of different operating conditions on the process separation performance were investigated by the parametrical sensitivities analysis. Then the optimal scenario could be obtained. At the same time, the heat exchanger network of the coupling process was modified which could increase the energy efficiency and reduce the cooling and heating utilities consumption. Moreover, the energy consumption of different processes were analyzed and evaluated to clarify the separation and recovery advantages of the novel coupling process. The results showed that the heating utilities of [C8Mim][BF4] and [C2Mim][BF4] were 11% and 13% of those of the initial scenarios, and the cooling utilities were 15% and 19% of those of the initial scenarios after the heat exchanger network modification. The lowest comprehensive energy consumption of the 2 stage membrane separation-flash evaporation coupling process was 3.9 GJthermal-eq/t IL ([C8Mim][BF4]) and 4.5 GJthermal-eq/t IL ([C2Mim][BF4]), which was only 20% ([C8Mim][BF4]) and 27% ([C2Mim][BF4]) of the direct vacuum flash evaporation process. The results of this study can provide theoretical basis and guidance for the future industrial application of ionic liquid recovery process.