烟气胺法CO2捕集技术进展与未来发展趋势

全球气候变化是目前世界面临的严峻问题之一,CO₂等温室气体的过量排放是导致全球气候变暖的主要原因。碳捕集、利用和封存(CCUS)是现阶段解决全球气候变暖的必要手段,基于有机胺的化学吸收法因捕集效率高、烟气适应性好,成为目前燃煤燃气电厂捕集CO₂的关键技术路径。本文详细介绍了胺法CO₂捕集技术的基本原理及胺法CO₂捕集技术工艺流程,分析了新型吸收剂的开发、节能技术的优化等降低胺法CO₂捕集技术再生能耗和成本的关键手段。结合研究现状以及烟气胺法CO₂捕集需求,对其未来的发展趋势进行展望。     

膜分离捕集燃煤电厂烟气CO2过程优化设计

全球CO₂的排放量不断升高,导致气候问题频发。“双碳”目标下,如何高效、低成本地捕集燃煤电厂烟气CO₂已经成为迫在眉睫的问题。传统的化学吸收法由于能耗高、成本高、溶剂易挥发等问题严重制约了其发展,而膜法碳捕集因为其操作简单、能耗低、环境污染小等优势被认为是最有前景的捕集方式。本文以PI中空纤维膜为分离膜,建立和求解了气体分离膜模型。并以燃煤电厂烟气CO₂为捕集目标,利用多岛遗传算法求解了膜分离捕集CO₂工艺的不同配置,并优化了分离过程中的关键参数(膜面积、操作压力)。结果显示：在二级膜分离工艺中,二级一段膜分离工艺的第一级膜和第二级膜操作压力分别为5.8 bar和7.1 bar,第一级膜和第二级膜的面积分别为448000 m²和180000 m²时,单位捕集成本为27.36 USD/t CO₂。与二级二段膜分离以及其他几种传统的CO₂捕集方法(MEA法、相变吸收法)相比,二级一段膜分离捕集CO₂的捕集成本和能耗均最小。本研究将为CO₂捕集实现低能耗和低成本化提供依据。     

金属离子促进乙醇胺捕集二氧化碳研究

为了解决醇胺法燃烧后捕集二氧化碳再生能耗过高的问题,研究了一种向胺溶液中添加金属离子以降低其CO₂解吸能耗的方法,称之为金属离子络合物热缓冲自热利用技术。以广泛商业化应用的单乙醇胺（MEA）溶液为研究载体,并在MEA溶液中分别添加金属离子铜或镍, 通过建立含有金属离子的MEA捕集CO₂体系的化学反应模型,解释金属离子热缓冲剂效应的内在机理。机理显示在MEA-金属离子-CO₂-H₂O体系中,金属-MEA络合物作为一种有效的反应热缓冲剂,将有机胺吸收CO₂过程中释放的反应热（放热反应）存储于金属络合物的解离键能中（吸热反应）,在CO₂高温解吸中通过其络合放热反应将储存的能量释放出来用于CO₂解吸,形成自热再生低能耗CO₂捕集技术,从而降低了MEA再生的能耗。本文进行了综合的实验测定来评价金属离子对MEA溶液捕集CO₂过程的性能提升影响,包括CO₂反应热、解吸速率、吸收-解吸循环负载、汽液平衡溶解度等。实验结果表明铜离子或镍离子作为添加剂,能增加MEA的CO₂平衡循环负载14%~20%或7%~10%,同时能够降低MEA的CO₂反应热值6.6%~24%或6.0%~20%。     

燃煤电厂烟气MDEA/PZ混合胺法碳捕集工艺模拟分析

采用混合胺吸收剂替代传统一乙醇胺（MEA）吸收剂是降低有机胺法碳捕集工艺能耗的重要方法。利用Aspen plus软件模拟了以甲基二乙醇胺(MDEA)/哌嗪(PZ)混合胺为吸收剂的燃煤电厂每年百万吨CO₂捕集工艺系统，考察了贫液负荷、MDEA/PZ混合胺浓度、MDEA/PZ比例和解吸压力等因素对解吸塔再沸器热负荷和冷凝器冷负荷的影响。通过对这些影响因素下吸收塔内液相温度分布和CO₂负荷分布变化揭示了MDEA/PZ对CO₂的吸收特性。此外，进一步分析了不同影响因素下解吸塔内气液相CO₂浓度驱动力和气液相级间温度驱动力分布特性，发现了强浓度驱动力和低温度驱动力分布更有利于降低再生能耗。研究表明，由30%MDEA和20%PZ组成的混合胺液在贫液负荷为0.08和解吸压力为2.02×10⁵Pa时，再沸器热负荷和塔顶冷凝负荷分别为2.76GJ/tCO₂和0.60GJ/tCO₂，相比传统MEA吸收剂降低了20.92%和40.0%。     

乙醇胺(MEA)法燃煤电厂CO2捕集系统尾气二次污染分析

在某燃煤电厂用乙醇胺(MEA)作吸收剂进行了CO₂燃烧后捕集中试,并对系统的排放物进行了分析。吸收塔尾气和再生气用GASMET烟气监测系统进行在线监测,可得到二者组分及含量。结合电厂烟气、连续监测系统(CEMS)数据及实验室溶液分析,根据烟气数据对MEA的挥发及降解情况作了研究,比较了系统前后烟气组分的变化,讨论其尾气对环境是否造成二次污染。试验结果表明:MEA在吸收塔中主要发生氧化降解,在再生塔中主要发生热降解,且溶剂损耗主要来自氧化降解和挥发;降解的主要产物为NH₃和乙醛,二者在气体中含量变化情况与溶液中MEA浓度变化基本一致;预洗塔能除去原烟气中部分酸性气体。故CO₂捕集系统可以进一步减少电厂净烟气中的原有污染物,但也会产生新的污染组分。新生成的污染物含量很少,符合国家标准,不会造成二次污染。     

高浓度氨水捕集二氧化碳的能耗与氨逃逸分析

针对低浓度氨水捕集CO₂速率慢、再生能耗高的问题，利用AspenPlus软件模拟高浓度氨水(质量分数为16%～22%)为吸收剂的燃煤电厂CO₂捕集工艺系统，对比高浓度与低浓度氨水捕集CO₂工艺的能耗特性与氨逃逸速率，揭示高浓度氨水脱碳过程中氨逃逸和能耗与氨水浓度、碳负载、解吸塔富液入口温度之间的关联特性。研究表明：再生过程中存在氨逃逸浓度转变的临界再生温度和贫液碳负载的限制，当氨水质量分数为20%时，再生温度不宜高于107℃，贫液碳负载率不宜低于0.25；与低浓度氨水(质量分数为4%～8%)脱碳相比，高浓度氨水脱碳工艺的CO₂再生能耗可降低26.2%～32.2%，考虑氨回收能耗后的总体能耗仍可降低21.6%～25%，为低能耗氨法碳捕集工艺的开发提供了指导。     

ZIF-8浆液中试分离CO2/N2过程模拟及能耗分析

ZIF-8/2-甲基咪唑-乙二醇-水浆液(ZIF-8浆液)可以高效低耗能地分离CO₂。为了进一步评估ZIF-8浆液在填料塔中分离CO₂的塔效率及能耗,使用Peng-Robinson(PR)状态方程,求出CO₂和ZIF-8浆液的二元交互作用参数(k_CO2),将二元交互作用参数和Aspen Plus软件进行关联,对CO₂/N₂多级吸收分离进行过程模拟。计算结果表明在中试填料塔中,ZIF-8浆液仅需要5块理论塔板即可将CO₂浓度由20%(mol)降低至2%(mol)以下,填料塔的塔板效率为25%。对中试分离CO₂/N₂进行能耗计算,结果表明当解吸条件为解吸温度333 K,解吸压力0.8 MPa和空气吹扫流量200 L/h时,CO₂捕集等效功最低可至0.474 GJ/t CO₂。在同样条件下使用ZIF-8浆液和MEA(30%(mass))水溶液进行碳捕集时,CO₂捕集等效功分别为0.507 GJ/t CO₂和0.957 GJ/t CO₂,ZIF-8浆液的CO₂捕集等效功仅为MEA水溶液的53%。     

烟气CO2捕集热能梯级利用节能工艺耦合优化

醇胺法捕集CO₂技术是一种较成熟的CO₂捕集技术,具有吸收速度快、脱除效果好等显著优点,但其操作费用高、解吸能耗大。本文以降低醇胺法捕集烟气中CO₂系统再生能耗为出发点,对常规醇胺法捕集CO₂工艺统进行了节能优化研究。在常规工艺流程基础上引入压缩式热泵节能技术,并利用Aspen Plus软件建立了基于压缩式热泵技术的CO₂捕集工艺流程模型。研究了压缩式热泵与机械蒸汽压缩回收（MVR）热泵、分流解吸、分布式换热、级间冷却4种节能工艺耦合,通过模拟计算与优化,结果说明了最佳节能工艺组合为“解吸塔压缩式热泵+贫液MVR热泵+分流解吸+级间冷却”耦合的CO₂捕集工艺流程,当解吸塔顶气体分流比为0.25∶0.75、冷富液分流比为0.05∶0.95、级间冷却器位于吸收塔17块塔板位置、吸收塔输入冷量为-3.0GJ/h时,系统再生能耗最低,为2.533 GJ/tCO₂,相比常规有机胺工艺（再生能耗4.204GJ/tCO₂）节能率39.748%。     

强化结晶氨法脱碳实验研究

针对目前氨法二氧化碳捕集技术中存在的氨逃逸、再生能耗高、反应后期吸收率低等问题提出了强化结晶氨法捕碳工艺,采用氨水乙醇组成的混合吸收液,利用半连续鼓泡反应系统研究了实验过程中吸收液组成、吸收温度、烟气流量及烟气中CO₂体积分数对吸收及结晶规律的影响。实验结果表明,混合吸收液中选用高比例乙醇、较低的吸收温度、较高的烟气流量以及较大的CO₂体积分数有利于吸收液中晶体出现时间提前,有利于强化结晶过程,晶体含氨量占初始氨总量的分数可达38.75%,并且混合吸收液的CO₂吸收能力较纯氨水工况明显提高。创新之处在于:提出了一种强化结晶氨法捕碳工艺,对氨水乙醇混合吸收液的吸收及结晶规律进行研究,给出了能够改善吸收效果并利于结晶过程的有利工况。为接下来新工艺的进一步研究提供基础数据和参考。     

固-液相变二氧化碳吸收剂的研究进展

基于有机胺的化学吸收法是燃烧后CO₂捕集行之有效的技术之一。然而,传统有机胺法的高再生能耗使其工业推广及应用受限。为降低CO₂捕集能耗,相变吸收剂应运而生。该类吸收剂吸收CO₂后由均相变为互不相溶的两相,CO₂主要富集于其中一相,仅需分离CO₂富相用于再生,即可大幅减少再生体积进而降低吸收剂捕集CO₂的再生能耗。相变吸收剂包括液-液相变吸收剂和固-液相变吸收剂,后者的CO₂吸收产物能以固体形式从溶液中沉淀析出,可实现产物快速分离,成为近年来相变吸收剂的研究热点。根据吸收剂的组分构成,固-液相变CO₂吸收剂主要可归为3类：有机胺非水溶液、盐溶液和离子液体固-液相变吸收剂。有机胺非水溶液以有机胺作为吸收活性组分、有机溶剂充当相分离剂,具有吸收速率快、腐蚀性小的优点,但其吸收CO₂后固相产物易形成黏稠胶状物且再生较困难;盐类固-液相变吸收剂主要包括氨基酸盐和碳酸盐水溶液或贫水溶液,具有成本低、原料...     

微通道内乙醇胺吸收CO2的过程特征（英文）

Process characteristics of CO2 absorption using aqueous monoethanolamine(MEA) in a microchannel reactor were investigated experimentally in this work.A T-type rectangular microchannel with a hydraulic diameter of 408 μm was used.Operating parameters,i.e.temperature,pressure and molar ratio of MEA to CO2 were studied.Under 3 MPa pressure,the mole fraction of CO2 in gas phase could decrease from 32.3% to 300×10?6 at least when gas hourly space velocity ranged from 14400 to 68600 h?1 and molar ratio of MEA to CO2 was kept at 2.2.In particular,the effects of temperature on CO2 absorption flux,mass transfer driving force,gas-liquid contact time and en-hancement factor were analyzed in detail and found that mass transfer enhancement by chemical reaction was a crucial factor for the process of CO2 absorption.     

离子液体水溶液吸收模拟烟气中SO2

建立了一套放大脱硫装置, 利用该装置研究了乙醇胺乳酸盐([MEA]L)水溶液在不同条件下吸收SO₂的性能, 确定出了较优的实验条件, 并在该条件下进行吸收-解吸SO₂循环实验。研究结果表明:烟气中SO₂的去除率随[MEA]L中水分的增加而增加;SO₂的去除率随着气液比的减少而增加, 在气液比为420, SO₂浓度为2850～14280 mg·m^-3范围内时, 出口烟气中SO₂浓度均小于285 mg·m^-3, 满足排放标准;烟气中的CO₂对[MEA]L水溶液吸收SO₂没有影响;利用蒸汽对富液进行解吸再生, 解吸后的贫液可以继续使用, 并且仍具有很高的SO₂去除率。     

The CO2 absorption and desorption performance of the triethylenetetramine + N,N-diethylethanolamine + H2O system

Post-combustion CO₂ capture (PCC) process faces significant challenge of high regeneration energy consumption. Biphasic absorbent is a promising alternative candidate which could significantly reduce the regeneration energy consumption because only the CO₂-concentrated phase should be regenerated. In this work, aqueous solutions of triethylenetetramine (TETA) and N,N-diethylethanolamine (DEEA) are found to be efficient biphasic absorbents of CO₂. The effects of the solvent composition, total amine concentration, and temperature on the absorption behavior, as well as the effect of temperature on the desorption behavior of TETA-DEEA-H₂O system were investigated. An aqueous solution of 1 mol·L^-1 TETA and 4 mol·L^-1 DEEA spontaneously separates into two liquid phases after a certain amount of CO₂ is absorbed and it shows high CO₂ absorption/desorption performance. About 99.4% of the absorbed CO₂ is found in the lower phase, which corresponds to a CO₂ absorption capacity of 3.44 mol·kg^-1. The appropriate absorption and desorption temperatures are found to be 30℃ and 90℃, respectively. The thermal analysis indicates that the heat of absorption of the 1 mol·L^-1 TETA and 4 mol·L^-1 DEEA solution is -84.38 kJ·(mol CO₂)^-1 which is 6.92 kJ·(mol CO₂)^-1 less than that of aqueous MEA. The reaction heat, sensible heat, and the vaporization heat of the TETA-DEEA-H₂O system are lower than that of the aqueous MEA, while its CO₂ capacity is higher. Thus the TETA-DEEA-H₂O system is potentially a better absorbent for the post-combustion CO₂ capture process.     

Performance of CO2 absorption in a diameter-varying spray tower

The application of spray towers for CO₂ capture is a development trend in recent years. However, most of the previous jobs were conducted in a cylindrical tower by using a single spray nozzle, whose configuration and performance is not good enough for industrial application. To solve this problem, the present work proposed a diameter-varying spray tower and a new spray mode of dual-nozzle opposed impinging spray to enhance the heat and mass transfer of CO₂ absorption process. Experiments were performed to investigate the mass transfer performance (in terms of the CO₂ removal rate (η) and the overall mass transfer coefficient (K_Ga_e2 are major factors, which affect the absorption performance and the maximums of η and K_Ga_e that are 94.0% and 0.574 kmol·m^-3·h^-1·kPa^-1, respectively, under the experimental conditions. Furthermore, new correlations to predict the mass transfer coefficient of the proposed spray tower are developed in various CO₂ concentrations with a Pearson Correlation Coefficient over 90%.     

Amine-immobilized HY zeolite for CO2 capture from hot flue gas

Solid amine-based adsorbents were widely studied as an alternative to liquid amine for post-combustion CO₂ capture (PCC). However, most of the amine adsorbents suffer from low thermal stability and poor cyclic regenerability at the temperature of hot flue gases. Here we present an amine loaded proton type Y zeolite (HY) where the amines namely monoethanolamine (MEA) and ethylenediamine (ED) are chemical immobilized via ionic bond to the zeolite framework to overcome the amine degradation problem. The MEA and ED of 5%, 10% and 20% (mass) concentration – immobilized zeolites were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, and N₂ -196 ℃ adsorption to confirm the structure integrity, amine functionalization, and surface area, respectively. The determination of the amine loading was given by C, H, N elemental analysis showing that ED has successfully grafted almost twice as many amino groups as MEA within the same solvent concentration. CO₂ adsorption capacity and thermal stability of these samples were measured using thermogravimetric analyser. The adsorption performance was tested at the adsorption temperature of 30, 60 and 90 ℃, respectively using pure CO₂ while the desorption was carried out with pure N₂ purge at the same temperature and then followed by elevated temperature at 150 ℃. It was found that all the amine@HY have a substantial high selectivity of CO₂ over N₂. The sample 20% ED@HY has the highest CO₂ adsorption capacity of 1.76 mmol·g^-1 at 90 ℃ higher than the capacity on parent NaY zeolite (1.45 mmol·g^-1 only). The amine@HY samples presented superior performance in cyclic thermal stability in the condition of the adsorption temperature of 90 ℃ and the desorption temperature of 150 ℃. These findings will foster the design of better adsorbents for CO₂ capture from flue gas in post-combustion power plants.     

CO2化学吸收法中再生气的陶瓷膜余热回收特性

在CO₂化学吸收法工艺中,采用富液分流工艺,利用在贫富液换热器前分流的冷富CO₂吸收剂溶液回收再生塔顶排出的热再生气（一般为CO₂和水蒸气混合气）的余热,有助于降低CO₂再生热耗。本文在乙醇胺（MEA）基富液分流化学吸收工艺中,以纳米级多孔亲水陶瓷膜作为分流冷富液和热再生气之间的换热介质,利用水的热质耦合传递强化余热的回收性能。以余热回收通量为指标,探讨了分流的MEA富液流量、温度、质量分数、CO₂负荷和热再生气流量及再生气中水蒸气摩尔分数对陶瓷膜热回收性能的影响,并对比了不同分离层孔径陶瓷膜的余热回收性能。结果显示,陶瓷膜的余热回收性能随MEA富液流量的增加而增加,但却随富液温度的升高而大幅下降。同时,随着气体流量和再生气中水蒸气摩尔分数的增大,热回收通量均会增大。由水传质所引发的对流换热对热回收通量具有促进作用,可占总热回收量的10%左右。由于CMHE-10陶瓷膜的分离层孔径与孔隙率均大于CMHE-4陶瓷膜,因而其水传质通量大于CMHE-4陶瓷膜。但CMHE-10陶瓷膜的有效热导率却低于CMHE-4陶瓷膜,因而热回收过程中其水蒸气的冷凝总量要小,导致其热回收性能低于CMHE-4陶瓷膜。     

填料吸收塔内乙醇胺溶液吸收CO2增强因子

醇胺溶液吸收CO₂是沼气提纯领域重要的研究课题。在实验填料吸收塔中,以NaOH水溶液吸收低浓度CO₂的实验结果估算了填料的有效相界面积,建立了乙醇胺（MEA）溶液吸收高浓度CO₂增强因子的数学模型,并从数学模型和实验的角度研究了MEA浓度、进气流率、CO₂浓度等工艺参数对MEA吸收CO₂增强因子的影响。结果表明,增强因子数学模型计算值与实验值能够良好吻合,MEA吸收CO₂化学反应增强因子随进气CO₂浓度增加而降低,随MEA浓度增加而增加,随进气流率增加而减小。     

Experimental study of the mass transfer behavior of carbon dioxide absorption into ternary phase change solution in a packed tower

Phase change absorbents for CO₂ are of great interest because they are expected to greatly reduce the heat energy consumption during the regeneration process. Compared with other phase change absorbents, monoethanolamine (MEA)-sulfolane-water is inexpensive and has a fast absorption rate. It is one of the most promising solvents for large-scale industrial applications. Therefore, this study investigates the mass transfer performance of this phase change system in the process of CO₂ absorption in a packed tower. By comparing the phase change absorbent and the ordinary absorbent, it is concluded that the use of MEA/sulfolane phase change absorbent has significantly improved mass transfer efficiency compared to a single MEA absorbent at the same concentration. In the 4 mol·L^-1 MEA/5 mol·L^-1 sulfolane system, the CO₂ loading of the upper liquid phase after phase separation is almost zero, while the volume of the lower liquid phase sent to the desorption operation is about half of the total volume of the absorbent, which greatly reduces the energy consumption. This study also investigates the influence of operating parameters such as lean CO₂ loading, gas and liquid flow rates, CO₂ partial pressure, and temperature on the volumetric mass transfer coefficient (K_Ga_V). The research shows that K_Ga_V increases with increasing liquid flow rate and decreases with the increase of lean CO₂ loading and CO₂ partial pressure, while the inert gas flow rate and temperature have little effect on K_Ga_V. In addition, based on the principle of phase change absorption, a predictive equation for the K_Ga_V of MEA-sulfolane in the packed tower was established. The K_Ga_V obtained from the experiment is consistent with the model prediction, and the absolute average deviation (AAD) is 7.8%.