以MDEA为主体的混合胺溶液吸收CO2研究进展

综述了近年来乙醇胺、二乙醇胺、哌嗪、碳酸酐酶以及离子液体与N-甲基二乙醇胺的混合溶液用于CO2吸收的研究进展;分析了混合溶液的吸收机理和CO2吸收的动力学;讨论了混合溶液组成、体系温度、压力等对吸收性能的影响;并对该法未来的研究方向和发展前景进行了展望.     

甲基二乙醇胺水溶液吸收CO_2的研究

溶剂吸收法捕集CO2是目前应用最为广泛的方法。以甲基二乙醇胺(MDEA)为吸收液,对其吸收混合气中CO2的性能进行了研究。实验结果表明,在MDEA中添加活化剂可以有效提高其吸收能力,在MDEA浓度为3 mol/L,活化剂浓度为0.3 mol/L时,哌嗪(PZ)的活化效果最好,对CO2的吸收容量最大。以PZ为活化剂的MDEA水溶液吸收CO2的适宜操作条件:MDEA浓度为3 mol/L,PZ浓度为0.6 mol/L,吸收温度为60℃。MDEA水溶液吸收CO2的性能随着PZ浓度的增加而增加。吸收液具有良好的再生性能,适宜的再生时间为3 h,再生温度为106℃。     

压力对N-甲基二乙醇胺混合哌嗪水溶液脱碳速率的影响

通过实验室填料塔研究了加压下(0. 2—0. 6MPa)哌嗪 (PZ)混合N 甲基二乙醇胺 (MDEA)水溶液吸收CO2的动力学。研究结果表明当CO2 分压大于 0. 1MPa时,压力会强化在气液界面的表面扰动,使得CO2 吸收速率较常压模型值大,并且该速率随压力的增大而增加。得到了哌嗪混合MDEA水溶液脱碳常压动力学模型的压力修正式。     

MDEA-PZ复合胺溶液吸收烟气中CO2实验研究

采用搅拌实验装置,研究不同摩尔配比的MDEA-PZ复合胺溶液对烟道气中CO2的吸收和解吸性能,揭示了吸收速率、吸收量与吸收时间、pH值、电位之间的内在联系;对CO2初始逸出温度、试液再生温度、再生率、再生pH值下降率进行了分析。结果表明,MDEA—PZ二元复合体系吸收效果优于单组分MDEA、PZ的吸收效果。MDEA—PZ复合胺溶液摩尔配比为0．5：0．5时,吸收效果最佳,吸收量约为0．8mol·L^-1;CO2初始逸出温度最低,为54℃;再生温度最低,为102℃;再生率最高,为88．61％;再生pH值下降率最低,为11．39％。MDEA-PZ复合体系的两种组分之间存在正交互作用。     

醇胺法吸收二氧化碳在填料塔中的应用

采用工业流程中的填料吸收塔和解吸塔,研究了乙醇胺(MEA)、哌嗪(PZ)、二乙烯三胺(DETA)、三乙烯四胺(TETA)与N-甲基二乙醇胺(MDEA)的混合溶液作为吸收剂对模拟合成气中CO2的吸收性能. 结果表明,胺活化性能依次为TETA>DETA>PZ>MEA;含TETA的吸收液可将尾气中CO2的浓度降至0.05%(mol),CO2脱除率达98.62%;增加活化剂浓度和降低气体流量有利于提高CO2脱除率;吸收-解吸循环条件下吸收速率是随吸收时间和活化剂浓度变化的指数递减函数.     

活化MDEA脱碳溶剂的研究

基于分子设计的原理,开发了一种醇胺分子结构中具有位阻效应的新型活化剂,评价了由新型活化剂和N-甲基二乙醇胺(MDEA)组成的活化脱碳溶液的吸收性能。试验结果表明,与常规烷醇活化剂相比,新型活化脱碳溶液吸收CO2的速度快、吸收容量大、处理能力高;相同条件下,位阻胺活化剂的处理能力比二乙醇胺(DEA)活化剂提高20%左右。     

Enhancement of kinetic rates of CO2 in aqueous solutions of piperazine and methyldiethanolamine with addition of sulfolane

Measurements of kinetics rates of CO₂ in aqueous solutions of methyldiethanolamine (MDEA), piperazine (PZ), and mixtures of (MDEA + PZ), (PZ + sulfolane) and (MDEA + sulfolane) were carried out using the stopped flow technique, and reported in terms of pseudo-first-order rate constants (k₀). When possible, the second-order reaction rate constants (k₂) were regressed from the data. Experiments were performed over new concentration ranges of (10–60), (200–800), (200–800, 10–40), (10–40, 10–200), and (200–800, 10–200) mol/m³ for the above-mentioned five systems, respectively, and at temperatures varying from (298.15–313.15 K). When sulfolane was added to the amine solution, pseudo-first-order rate constants in the mixed solvents were higher than in aqueous MDEA and PZ solutions at all temperatures. The kinetic rates were highest at 298.15 K and decreased at higher temperatures for aqueous (MDEA + sulfolane) solutions but increased with temperature for aqueous (PZ + sulfolane) systems. Reaction orders for both PZ and MDEA were practically one at all sulfolane concentrations and temperatures. The base catalysis mechanism was used to regress very well data for aqueous MDEA and (MDEA + sulfolane + water) and the termolecular mechanism was used for (PZ + sulfolane + water) system. Both the zwitterion and termolecular models were able to fit the experimental data for the aqueous PZ system well. Finally, the termolecular and a hybrid model based on the combination of the Zwitterion and base catalysis mechanisms were able to successfully correlate the experimental data for the mixed aqueous (MDEA + PZ) systems.     

膜基气体吸收过程中活化剂的活化性能比较

将AMP(2-甲基-2-氨基-1-丙醇)和PZ(哌嗪)作为活化剂,分别添加于MDEA(N-甲基二乙醇胺)溶液中组成复合溶液,在膜吸收装置上考察了其吸收CO2性能. 通过气液流速、气相组成、液相浓度、负载、膜组件结构和膜结构形态等对总传质系数Kov影响的比较,研究了具有多氨基环状结构的化合物PZ和空间位阻结构的化合物AMP在膜气体吸收过程中对传质的加强作用. 结果表明,多氨基化合物PZ比空间位阻胺AMP活化效应更大,PZ对传质的加强作用高于AMP,流体力学因素对传质的影响有限,活化剂的化学活化作用对传质的影响是关键性因素,动力学因素对传质具有本质上的作用.     

MDEA与哌嗪、二乙醇胺混合溶液吸收二氧化碳速率研究

Absorption rate of CO2 into aqueous solution of N-methyldiethanolamine (MDEA) blended with diethanolamine (DEA) and piperazine (PZ) was studied and a kinetic model was established. It is shown that homogeneous activation mechanism could explain this absorption process. The absorption rate coefficients of carbon dioxide into MDEA aqueous solution blended with DEA, PZ or DEA PZ were compared with each other. The results demonstrated that the different activation effect of DEA, PZ and DEA PZ on the carbon dioxide absorption comes from the difference in CO2 combination rate, transport of PZ and DEA to MDEA and the regeneration rate of PZ and DEA.     

MDEA-TBEE复合溶剂吸收酸性气体性能的研究

合成了一种空间位阻胺TBEE(叔丁氨基乙氧基乙醇),并添加在MDEA溶剂中组成MDEA-TBEE复合溶剂。设计了,一套新颖的气体吸收装置-恒温填料反应器,测定了该复合溶剂吸收酸性气体(H2S,CO2)的性能。通过大量的实验数据,分析了影响吸收性能的各种因素(如吸收剂浓度、MDEA／TBEE摩尔比、反应温度及溶液负载),并将复合溶剂的吸收性能同MDEA及其它有机胺(MEA、DEA、DIPA)作了比较。实验表明,与MDEA或其它有机胺比较,MDEA-TBEE复合溶剂具有更高的吸收负荷和对H2S具有高选择性。实验同时证明了空间位阻胺是一种优良的酸性气体吸收剂。     

A study on the reaction between CO2 and alkanolamines in aqueous solutions

Literature data on the rates of reaction between CO₂ and alkanolamines (MEA, DEA, DIPA, TEA and MDEA) in aqueous solution are discussed. These data induced us to carry out absorption experiments of CO₂ into aqueous DEA, DIPA, TEA and MDEA solutions from which the respective rate constantsThe results for DEA and DIPA were analysed by means of a zwitterion-mechanism which was derived from the mechanism originally proposed by Danckwerts [1The reaction rate of CO₂ with aqueous TEA and MDEA solutions shows a significant base catalysis effect which is also reported by Donaldson and Nguy     

MDEA-TBEE复合溶液选择性吸收H_2S性能评价

将一种强空间位阻胺TBEE(叔丁氨基乙氧基乙醇)添加于MDEA(N-甲基二乙醇胺)溶液中形成复合溶液MDEA-TBEE,以填料柱为反应器,采用常压吸收-常压再生操作流程,研究了复合溶液从混合气中选择性吸收H2S吸收性能,并与单组分吸收剂MDEA溶液吸收性能作比较,以脱除率、选择性、溶液负载和容量为评价指标,评价了再生温度、原料气CO2/H2S摩尔比、气液比和贫液负载等因素对复合溶液选择性吸收H2S性能的影响。结果表明,复合溶液比MDEA溶液易于再生,H2S脱除率高于MDEA溶液;复合溶液的容量大于MDEA溶液,平均是MDEA的1.25倍;随着气液比增大,H2S脱除率下降,选择性有所上升。     

A study on the reaction between CO2 and alkanolamines in aqueous solutions

Literature data on the rates of reaction between CO₂ and alkanolamines (MEA, DEA, DIPA, TEA and MDEA) in aqueous solution are discussed. These data induced us to carry out absorption experiments of CO₂ into aqueous DEA, DIPA, TEA and MDEA solutions from which the respective rate constants were derived. The experimental technique was similar to that used by Laddha and Danckwerts[30].The results for DEA and DIPA were analysed by means of a zwitterion-mechanism which was derived from the mechanism originally proposed by Danckwerts[16The reaction rate of CO₂ with aqueous TEA and MDEA solutions shows a significant base catalysis effect which is also reported by Donaldson and Nguy     

基于中空纤维膜的混合富CO2吸收液解吸及再生

用中空纤维膜接触器(FMC)作解吸装置,选取N-甲基二乙醇胺(MDEA)?二乙醇胺(DEA)混合吸收剂为富CO2吸收液进行膜法解吸及再生实验,考察了解吸温度、解吸压力和液相流速对解吸效果的影响,研究了再生液的CO2二次吸收和解吸性能. 结果表明,在取样时间20和40 min下,混合吸收剂最佳溶质摩尔比为MDEA:DEA=1:0.6. 适当增大解吸温度、液相流速及负压压强可有效提高CO2的释放流量和解吸率. 60℃时CO2释放流量峰值为101.29 mL/min (峰值前移),CO2最终解吸率为61.51%,比30℃时分别提高了56.14%和50.5%;解吸压力20 kPa时CO2释放流量峰值和最终解吸率分别为96.17 mL/min (峰值前移)和58.66%,比65 kPa时分别提高了62.21%和16.85%. 流速为0.08 m/s时CO2释放流量峰值为88.65 mL/min (峰值未前移),最终解吸率为55.63%,比0.02 m/s时分别提高了43.45%和30.13%. MDEA?DEA再生液循环使用5次后CO2吸收容量为原液的70%,二次解吸率为原液的60%,无明显下降. 膜法解吸混合富CO2吸收液效果良好,且再生液具有优异的二次吸收和解吸性能.     

天然气半贫液脱碳工艺三元胺液配方优选

为实现天然气脱碳工厂降本增效目标,基于某工厂PZ活化MDEA半贫液工艺,在现有设备能力下进一步提升胺液性能,进行三元复配胺液配方筛选以替代原有吸收剂。本文针对单一胺液的贫液、半贫液及富液分别进行实验,确定合适的主体胺液及添加剂,将胺液进行三元复配后通过实验探究三元复配胺液的吸收及再生性能,旨在寻找吸收容量大、吸收速率快、解吸率高、循环溶解度高、再生能耗低综合性能优的胺液配方。通过研究发现,单一胺液中AMP、DETA及PZ吸收性能较优,TEA再生能耗最低,解吸率最高;对于三元复配胺液而言,当MDEA/DEEA为主体胺液时,两种胺液配方贫液状态下的吸收速率和吸收负荷均较高,MDEA/TEA双主体胺液的最终解吸率高于MDEA/DEEA双主体胺液,TEA的加入显著提高了胺液的解吸率;筛选得到的三元高效胺液配方18%MDEA+18%TEA+4%PZ的半贫液循环溶解度高于原PZ活化MDEA配方,再生能耗较低,可代替PZ活化MDEA胺液应用于天然气半贫液脱碳工艺。     

填料塔中混合胺吸收二氧化碳的研究

在填料塔中考察了常压下混合胺吸收剂[20%乙醇胺(MEA)+2% N-甲基二乙醇胺(MDEA),20%羟乙基乙二胺(AEE)+2% MDEA]对CO_2的吸收与解吸效果.同时测得了AEE+MDEA混合胺体系吸收剂脱除空气中体积分数约10%的CO_2的体积总传质系数K_Ga_v的近似值,并考察了进口气体中CO_2摩尔流量、气体流量、液体流量等因素对K_Ga_v的影响.实验结果表明,AEE+MDEA吸收效果明显好于MEA+MDEA,并且二者解吸效果相同;K_Ga_v随CO_2摩尔流量、气体流量、液体流量增大而增大.     

MDEA溶液吸收CO_2动力学研究

采用圆盘塔,在常压、温度30～70℃、MDEA浓度1.75～4.28kmol/m~3条件下,以流动循环法测定了MDEA水溶液吸收CO_2的速率.利用自吸式搅拌鼓泡反应器测得的气液平衡关系整理数据,所有吸收速率数据均可用假一级快速可逆反应的吸收速率表达式来描述,即N_(co_2)=H_(co_2)(D_(co_2l)k_2c°_(Am)(1-a)~(1/2)(p_(co_2)-p_(co_2l)~*)式中k_2=5.86×10~6exp(-3984/T)并由此求得表观活化能为33.13kJ/mol.本文还讨论了温度、转化度和MDEA浓度对CO_2吸收速率的影响.     

DEA复配水溶液二氧化碳溶解度的测定实验

设计了测定CO2在溶液中溶解度的实验装置,并对2 mol/L的DEA水溶液分别在温度条件为308 K、318 K、328 K、358 K,CO2分压力范围0～150 kPa时的CO2溶解度进行了测定。并选取MDEA、DETA、AEE和SG作为代表添加物,测定了添加剂与DEA 摩尔比为1∶3、醇胺总浓度为2mol/L的条件下溶液中CO2的溶解度。结果表明,在实验压力范围内,DEA溶液中CO2溶解度随压力增大逐渐增大随温度升高而减小;对DEA溶液中CO2的溶解度影响大小顺序为DETA > AEE > SG > MDEA。     

三乙醇胺+哌嗪混合胺液的脱碳性能及配比优选

胺法脱碳以其脱除效果好、能耗低等优点在天然气预处理中得到广泛应用,目前国内外普遍采用以MDEA为主体的复配胺液为吸收剂.本文选取同为叔胺的TEA为主体进行实验研究,在TEA反应机理的研究基础上,选取哌嗪作为添加剂,对三乙醇胺+哌嗪混合胺液进行脱碳性能研究,通过吸收、解吸及酸解实验,对不同配比的三乙醇胺+哌嗪混合胺液的吸收、解吸及循环性能进行了深入地对比分析.实验结果表明,哌嗪的添加量越大,三乙醇胺+哌嗪混合胺液的吸收效果越好,但这一现象会随着哌嗪添加量的增大而不明显.而添加哌嗪对三乙醇胺的解吸性能并无明显改善.     

混合醇胺溶液吸收烟气中CO2

研究了温度、CO2含量与吸收液浓度对醇胺溶液吸收CO2性能的影响,并比较了不同复配体系对二异丙醇胺(MDEA)的活化效果。结果表明,醇胺溶液对CO2的吸收速率随反应时间的增加而降低,随吸收温度的升高而增强,以40℃为宜;吸收反应速率均随气、液相反应物含量增大而增强;混合体系对MDEA的活化效果为二乙烯二胺最好,乙醇胺最差。