富氧燃烧烟气冷凝塔钠碱法脱硫过程SO_2和CO_2共吸收建模与实验研究  

Experimental and modelling study on co-absorption of SO_2 and CO_2 during desulfurization process by flue gas cooler for oxy-fuel combustion flue gas

作　　者：刘敦禹[1] Terry Wall Rohan Stanger LIU Dunyu;WALL Terry;STANGER Rohan(School of Energy and Power Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;Chemical Engineering,University of Newcastle,NSW Newcastle 2308,Australia)

机构地区：[1]上海理工大学能源与动力工程学院,上海200093 [2]Chemical Engineering,University of Newcastle

出　　处：《化工学报》2018年第9期4019-4029,共11页CIESC Journal

基　　金：上海市浦江人才项目(16PJ1407900);澳大利亚清洁煤研究和发展项目(6-0710-0061)~~

摘　　要：建立SO_2与CO_2共吸收到钠基溶液中的吸收速率模型,假设该模型中SO_2的水解反应为瞬间反应;关于CO_2水解反应存在两种假设:有限动力学假设和瞬间反应假设。由这两种方法计算分别获得SO_2的吸收速率并与完全预混气液反应器中的的动态实验进行对比。采用瞬间反应假设可以预测反应速率的趋势,绝对反应速率误差仍然较大。而采用有限动力学假设的模拟值与实验值在pH>3吻合良好。CO_2对SO_2吸收速率的影响主要通过影响气相传质系数和相同pH下溶液总硫浓度产生。根据CO_2存在与否对SO_2吸收速率的影响,获得五个不同的相互作用pH的区间。pH>11.42时,SO_2/N_2吸收速率大于SO_2/CO_2,主要由于气相传质系数影响;7.8<pH<11.42时,SO_2/N_2的吸收速率和SO_2/CO_2吸收速率相似,主要由于气相传质系数和溶液总硫影响抵消;5.41<pH<7.8时,SO_2/CO_2的吸收速率相对较高,主要由于溶液总硫影响更大;2.8<pH<5.41时,SO_2/CO_2的吸收速率相对较低,主要由于气相传质系数影响;pH<2.8时,SO_2/N_2和SO_2/CO_2吸收速率相似,主要受液相传质的控制。模拟同时获得不同pH下溶液中碳和硫相关离子的转化规律和SO_2吸收速率的控制步骤,为富氧燃烧冷却塔同时脱硫设备的设计和运行提供参考。This paper aims to set up the theoretical model for co-absorption of SO2 and CO2 into sodium based solutions.Instantaneous reaction for SO2 hydrolysis is assumed.For the hydrolysis of CO2,there are two assumptions:finite kinetics and instantaneous reaction.Based on these two assumptions,the absorption rates of SO2 were separately calculated and compared with dynamic experiments in the well stirred reactor.The trend for the absorption rate of SO2 was well predicted by the instantaneous reaction for CO2.The relative error for the absolute rates of SO2 is high.The prediction based on the finite kinetics for CO2 hydrolysis at pH>3 agrees well with experiments.The influences of CO2 on the SO2 absorption rate is primarily through gas phase mass transfer coefficient and total sulphur concentration at the same pH.Depending on the existence of CO2 on SO2 absorption rate,five pH regimes for interaction were observed.At pH>11.42,the absorption rate of SO2/N2 is higher than that of SO2/CO2 due to the influence of gas phase mass transfer coefficient.At 7.8<pH<11.42,the absorption rate of SO2/N2 is similar with that of SO2/CO2 due to the counteraction of gas phase mass transfer coefficient and total sulphur in liquid.At 5.41<pH<7.8,the absorption rate of SO2/CO2 is higher due to the influence of total sulphur in liquid.At 2.8<pH<5.41,the absorption rate of SO2/CO2 is relative lower primarily due to the influence of gas phase mass transfer coefficient.At pH<2.8,the absorption rate of SO2/N2 is similar with that of SO2/CO2 due to liquid phase controlled region.Conversion of carbon and sulphur based ions at different pH and controlling regions for SO2 absorption rate were obtained.The work provides guidance for the design and operation of flue gas cooler for oxy-fuel combustion flue gas.

关 键 词：富氧燃烧 冷却塔 吸收 

分 类 号：TQ02[化学工程]