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过程工程学报 ›› 2021, Vol. 21 ›› Issue (3): 353-362.DOI: 10.12034/j.issn.1009-606X.219366

• 环境与能源 • 上一篇    下一篇

响应面法优化解吸MDEA/PG富液中CO2再生工艺

张卫风*,李娟,王秋华   

  1. 华东交通大学土木建筑学院, 江西 南昌 330013
  • 收稿日期:2019-12-10 修回日期:2020-05-20 出版日期:2021-03-22 发布日期:2021-03-23
  • 通讯作者: 张卫风

Response surface methodology for optimizing CO2 regeneration in MDEA/PG rich solutions

Weifeng ZHANG*, Juan LI, Qiuhua WANG   

  1. School of Civil Engineering Architecture, East China Jiaotong University, Nanchang, Jiangxi 330013, China
  • Received:2019-12-10 Revised:2020-05-20 Online:2021-03-22 Published:2021-03-23
  • Contact: zhang zhangweifeng

摘要: 钙法是利用Ca(OH)2夺取富液中CO2来解吸富液,并以CaCO3形式固定CO2的一种低能耗、低成本的化学再生方法。用Box-Behnken Design(BBD)响应面法对钙法解吸MDEA/PG富液过程进行优化,设定CO2负荷、Ca(OH)2投加量、反应时间和搅拌速率4个影响因子,CO2解吸率为响应值,分析优化得出该方法的最佳解吸条件,并按此条件进行了多重再生–矿化循环动态试验,结合XRD和TEM图对碳酸化反应进行了探讨。结果表明,CO2负荷、Ca(OH)2投加量和搅拌速率对CO2解吸率有显著影响。富液再生的最佳工艺条件是CO2负荷0.8 mol/L、Ca(OH)2投加量1:1、反应时间20 min、搅拌速率800 r/min,此条件下解吸率为83.68%。钙法解吸后MDEA/PG再生液具有良好的可重复使用性。Ca(OH)2可有效矿化封存CO2并能再生MDEA/PG。

关键词: 二氧化碳, 氢氧化钙, 矿化, 解吸率, 再生工艺, 响应面分析

Abstract: Post-combustion CO2 capture (PCC) facilities are set up at the power plants to reduce substantial carbon dioxide emissions. However, the significant energy penalty and high capital cost remain the most critical challenge hindering the large-scale application of amine-based PCC technologies. Also, CO2 enriched by amine-based scrubbing requires storage processes. To overcome the shortage of CO2 desorption process, a chemical regeneration process was developed in which uses Ca(OH)2 to capture CO2 from rich solution and fix CO2 in the form of CaCO3. The Box-Behnken Design methodology was used to optimize desorption conditions, including CO2 loading, Ca(OH)2 dosage, reaction time and stirring rate. The performance stability of the MDEA/PG was verified in multiple regeneration-mineralization dynamic cycle experiments under the optimal conditions. We further confirm the coordinated mechanism of carbonation reaction between CO2 and Ca(OH)2 using X-ray diffraction (XRD) and transmission electron microscope (TEM). The desorption-mineralization experiment was performed in a flask with three necks respectively. Acid titration was used to measure the CO2 loading of the liquid sample. XRD and TEM were respectively used to determine the composition of solid products and observe the micromorphology of carbonated products after regeneration. The CO2 loading, Ca(OH)2 dosage and stirring rate were the three key factors influencing the uptake of desorption rate. The optimal desorption conditions were CO2 loading 0.8 mol/L, Ca(OH)2 dosage 1:1, reaction time 20 min, stirring rate 800 r/min, and under these conditions, their desorption rate was 83.68%. The results of multiple desorption-mineralization cycle dynamic experiments showed that the regenerated solution of MDEA/PG desorbed by calcium method has good reusability. The results of X-ray diffraction and transmission electron microscope after carbonation also confirmed that Ca(OH)2 can effectively mineralize CO2 and regenerate MDEA/PG. The chemical regeneration process can effectively reduce and reuse emitted CO2, thereby making CO2 a potential future resource.

Key words: carbon dioxide, amine solution, calcium hydroxide, mineralization, regeneration process, response surface analysis