响应面法优化解吸MDEA/PG富液中CO2再生工艺

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-BehnkenDesign(BBD)响应面法对钙法解吸MDEA/PG富液过程进行优化,设定CC2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...

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

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.