Simulation And Process Improvement Of Carbon Dioxide Capture Systems For Coal-fired Power Plant Flue Gas

In the la st deca de s, the e xcessive e missi on of CO₂has become ani mportant issue tha t we ha ve to fa ce a nd solve i mme diat ely. CO₂capturefrom coal-fired power pl ants, refineries, and natural gas processingplants—the large point sources of CO₂—is important for mitigation o fgreenhouse e ffe ct.In t his pa per, a n absorption-desor ption system （150mm diameter of twocolumns） based on traditional MEA-CO₂ca ptur e pr ocess was buil t usi ngAspen plus V7.1/Pr omax3.0. This pa pe r started with the perspecti ve of howto reduce the solvent loss, considering t he evapor ation of MEA and H₂O notonly t he detri ment of air pollution, water wast e, but also the effect of theeconomy of the entire system. Si mulations we re conduc ted to investigatethe effect s of t he operati ng parameters （flue gas temper ature, operatingpressure, liquid flow rate, CO₂lean loading, MEA conce ntration, condenserte mperature, and re boiler dut y） and sc rubber unit on t he loss of MEA an dH₂O, a nd to obtai n the opti mal pr ocess par a mete rs. The simulation resultsshowed that the operating parameters had gr eat i mpact on the loss of MEAand H₂O, and the scrubber unit made the l oss of MEA and H₂O r e duce to8.88×10-10kg/kgCO₂and0.59kg/kgCO₂, about100%a nd8.1%l ower t hanthe captur e process without scrubber respectively.Ai ming at solving the problem of high energy c onsumpti on in e xistingpost-c ombustion CO₂capt ur e pr ocess, a MEA-based capt ure proce ss modelof a300MW c oal-fire d power pla nt was esta blished and si mul at ed usingAspen pl us V7.1. The i nfluences of CO₂lean loading, feed location ofstripper, t e mperatur e a ppr oac h of lean-rich heat exchanger and condense rtemperature on the the heat consumpti on for re generation were i nve stigatedand studied. The design specification and sensitivity analysis function inAspen plus were use d to opti mize pr ocess para me t ers of the re moval syste m.The pr oce ss para me ters of the syste m were obtained, and the opti mal resultfor heat consumption for re generation of traditional CO₂c apture pr ocess is3.35GJ/t.The tradi tional ca pture process wa s i mpr ove d by c ombining se gme ntabsorption process with heat-pump distillation technology. The new MEA-CO₂capture processes of a bsor ption split combined with heat-pumpdistillation and absorption and desorption split combined with heat-pumpdistillation MEA-CO₂capt ure proc ess were pr opose d, Based on t hetraditional capture process, parameter sensitivity analysis of the newprocess c onfigurati ons was done, t he result of optimization to mini mize t hereboiler duty for two ne w process configur ations showe d the opti malprocess para meter s reduce d the r eboiler duty to3.17GJ/t,2.09GJ/trespecti ve ly, a bout5.4%and37.7%lowe r t han t raditional capt ure process.