二元复合溶液脱除烟气中CO2的过程模拟与评价

为探究吸收容量大、再生能力较强的吸收剂复合吸收燃烧烟气中CO₂的性能,采用N-甲基二乙醇胺-哌嗪（MDEA-PZ）、碳酸钾-哌嗪（K₂CO₃-PZ）以及氨水-哌嗪（NH₃-PZ）3种二元复合溶液,基于Rate-based模型对其进行脱碳性能过程模拟。以吸收剂的摩尔流量、温度以及摩尔分数配比（X∶PZ）3个因素进行单因素研究,并在此基础上采用正交试验的方法得出最佳工艺方案。结果表明,随着吸收剂的摩尔流量上升、温度下降以及吸收剂中PZ摩尔分数上升,CO₂吸收效率呈上升趋势。在最佳工艺方案中,K₂CO₃-PZ二元复合溶液最佳吸收温度为40℃,MDEA-PZ和NH₃-PZ两种二元复合溶液最佳吸收温度为30℃;3种二元复合溶液最佳摩尔流量为3.5×10⁵kmol/h,最佳摩尔分数配比为60%∶40%。在各自最佳工艺以及其他条件相同的情况下,吸收CO₂性能的优劣依次为MDEA-PZ、NH₃-PZ以及K₂CO₃-PZ。     

相变吸收捕集烟气中CO2技术的发展现状

化学吸收法作为目前最有效的CO₂捕集技术,吸收剂常用有机胺,但过高的再生能耗和成本限制了其在工业中的应用。基于传统有机胺溶剂开发出来的相变吸收剂被认为可以大幅减少解吸能耗,成为近几年研究的热点。本文详细介绍了相变吸收剂的常见类型、分相机理,并根据其具体组成进行了种类划分,对比分析了常用相变吸收剂和传统乙醇胺（MEA）吸收液的再生能耗,并指出温度、CO₂负荷以及相分离等因素对相变吸收剂的工艺流程长期运行稳定性的影响。在制备相变吸收剂的过程中,可加入活化剂来降低CO₂富液黏度,加入助溶剂来提高传质特性。本文阐述了现有相变吸收剂的挥发、降解和腐蚀等特性的研究现状。最后,结合研究现状和烟气捕集需求对相变吸收剂今后的研究方向给出了建议。     

燃煤烟气中SO2对氨法脱碳的影响

利用湿壁塔实验台对燃煤烟气中SO₂对氨水溶液［1%～7%(质量）］吸收CO₂的影响进行了实验研究,具体分析了不同反应温度（20～80℃）和CO₂体积分数（5%～20%）条件下,CO₂传质通量及传质系数随SO₂浓度和SO₂负载量的变化规律。结果表明, SO₂浓度由0增至11428 mg·m^-3,CO₂传质通量及传质系数均有一半左右降幅,而SO₂负载量［0.1～0.4 mol SO₂·（mol NH₃）^-1］的增加,同样导致CO₂传质通量及传质系数明显减小。氨水浓度及反应温度增加可有效提高CO₂传质通量和传质系数,相对降低SO₂对CO₂传质的影响。CO₂浓度的增加可明显提高其传质通量,但是CO₂的传质系数有所降低。     

聚乙烯胺/埃洛石纳米管混合基质膜的制备及其CO2/N2分离

制备高性能的气体分离膜,是实现CO₂高效回收的关键。为了提高CO₂分离膜的性能,将中空管状结构的埃洛石纳米管（HNTs）添加到聚乙烯胺（PVAm）中配制涂膜液,并将PVAm-HNTs涂膜液涂覆到聚砜（PSf）超滤膜上制备PVAm-HNTs/PSf混合基质膜。其中PSf超滤膜作为支撑层,PVAm-HNTs致密涂层作为功能层,功能层结构与形态对CO₂分离具有关键作用。采用XRD、SEM对HNTs的结构与形态进行表征,并借助FTIR和SEM对膜的形态与结构进行分析。在进料气为纯气条件下,系统地研究了HNTs添加量、进料压力、PVAm-HNTs涂层厚度对PVAm-HNTs/PSf膜的CO₂分离性能影响,并考察了混合基质膜的CO₂/N₂混合气分离性能。结果显示：在水溶液中显示正电性的PVAm与负电性的HNTs具有较好的界面相容性。HNTs添加量为1%（质量）、PVAm-HNTs湿涂层厚度为50 μm的混合基质膜,表现出最优的CO₂分离性能。在进料气压力为0.1 MPa、测试温度为25℃、CO₂/N₂（15/85,体积比）混合气进料的条件下,膜的CO₂渗透速率为178 GPU,CO₂/N₂选择性为83;该膜具有较好的稳定性,经过120 h运行后,渗透性和选择性仍能保持稳定。     

Metal-organic framework-based CO2 capture: from precise material design to high-efficiency membranes

A low-carbon economy calls for CO₂ capture technologies. Membrane separations represent an energy-efficient and environment-friendly process compared with distillations and solvent absorptions. Metal-organic frameworks (MOFs), as a novel type of porous materials, are being generated at a rapid and growing pace, which provide more opportunities for high-efficiency CO₂ capture. In this review, we illustrate a conceptional framework from material design and membrane separation application for CO₂ capture, and emphasize two importance themes, namely (i) design and modification of CO₂-philic MOF materials that targets secondary building units, pore structure, topology and hybridization and (ii) construction of crack-free membranes through chemical epitaxy growth of active building blocks, interfacial assembly, ultrathin two-dimensional nanosheet assembly and mixed-matrix integration strategies, which would give rise to the most promising membrane performances for CO₂ capture, and be expected to overcome the bottleneck of permeability-selectivity limitations.     

Polyurethane-based poly (ionic liquid)s for CO2 removal from natural gas

Carbon dioxide separation from CH₄ is important to the environment and natural gas processing. Poly (ionic liquid)s (PILs) based on polyurethane structures are considered as potential materials for CO₂ capture. Thus, a series of anionic PILs based on polyurethane were synthesized. The effects of polyol chemical structure and counter-cations (imidazolium, phosphonium, ammonium, and pyridinium) in CO₂ sorption capacity and CO₂/CH₄ separation performance were evaluated. The synthesized PILs were characterized by NMR, DSC, TGA, dinamical mechanical thermo analysis (DMTA), SEM, and AFM. CO₂ sorption, reusability, and CO₂/CH₄ selectivity were assessed by the pressure-decay technique. The counter-cation and polyol chemical structure play an important role in CO₂ sorption and CO₂/CH₄ selectivity. PILs exhibited competitive thermal mechanical properties. Results showed that PILPC-TBP was the best poly (ionic liquid) for CO₂/CH₄ separation. Moreover, poly (liquid ionic) base polyol (polycarbonate) with phosphonium (PILPC-TBP) demonstrated higher CO₂ sorption capacity (21.4 mgCO₂/g at 303.15 K and 0.08 MPa) as compared to other reported poly (ionic liquids). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47536.     

超枝化固体胺吸附分离烟气中二氧化碳

采用浸渍方法将四乙烯五胺（TEPA）负载到KIT-6介孔硅材料孔道表面上合成超枝化固体胺KIT-6(TEPA),并对其吸附CO₂性能进行研究。结果表明,随着温度的升高,KIT-6(TEPA)的CO₂吸附量呈增长趋势,343 K时获得最大吸附量（3.1 mmol·g^-1）。继续升高温度吸附量则呈下降趋势。KIT-6(TEPA)吸附CO₂过程以化学吸附为主,化学吸附量占总吸附量的97.2%以上（323相似文献   

含有MCM-41分子筛的混合基质复合膜用于CO2分离

为了提高CO₂分离膜的性能,将接枝了氨基的MCM-41分子筛(MCM-NH₂)添加到聚乙烯基胺(PVAm)水溶液中配制涂膜液,并将PVAm-MCM-NH₂涂膜液涂覆到聚砜(PSf)超滤膜上制备PVAm-MCM-NH₂/PSf混合基质复合膜。复合膜分离层较薄,有利于CO₂渗透速率的提高。接枝的胺基提高了分子筛与聚合物的相容性和膜内胺基含量,有利于膜渗透选择性能的提高。使用CO₂/N₂混合气(15% CO₂ + 85% N₂,体积分数)考察了不同MCM-NH₂添加量的PVAm-MCM-NH₂/PSf膜的渗透选择性能。当涂膜液中m_MCM-NH2/m_PVAm为0.2、湿涂层厚度为50 μm,测试温度为22℃ 、进料气压力为0.11 MPa时,膜的CO₂渗透速率可达4.66×10^-7 mol·m^-2·s^-1·Pa^-1,CO₂/N₂分离因子可达150。较高的CO₂/N₂分离性能表明PVAm-MCM-NH₂/PSf膜在烟道气碳捕集领域具有良好的应用前景。此外,考察了湿涂层厚度、热处理、添加小分子胺等条件对膜渗透选择性能的影响。     

Technico‐economical assessment of MFI‐type zeolite membranes for CO2 capture from postcombustion flue gases

A detailed survey of the effect of moisture on the CO₂/N₂ permeation and separation performance of Mobile Five (MFI) zeolite membranes in view of downstream postcombustion CO₂ capture applications in power plants and incinerators is presented. The membranes, displaying a nanocomposite architecture, have been prepared on α‐alumina tubes by pore‐plugging hydrothermal synthesis at 443 K for 89 h using a precursor clear solution with molar composition 1 SiO₂:0.45 tetrapropylammonium hydroxide:27.8 H₂O. The synthesized membranes present reasonable permeation and CO₂/N₂ separation properties even in the presence of high water concentrations in the gas stream. A critical discussion is also provided on the technico‐economical feasibility (i.e., CO₂ recovery, CO₂ purity in the permeate, module volume, and energy consumption) of a membrane cascade unit for CO₂ capture and liquefaction/supercritical storage from standard flue gases emitted from an incinerator. Our results suggest that the permeate pressure should be kept under primary vacuum to promote the CO₂ driving force within the membrane. © 2011 American Institute of Chemical Engineers AIChE J, 58: 3183–3194, 2012     

Efficient capture of CO2 from flue gas at high temperature by tunable polyamine-based hybrid ionic liquids

For an ideal absorbent for CO₂ capture from flue gas, there are some key features including easy preparation, high stability, low absorption enthalpy, high capacity at high temperature and excellent reversibility. Herein, several polyamine-functionalized ionic liquids (ILs) were easily prepared from cheap polyamines and lithium salts, which exhibited significantly improved stability due to the presence of multisite coordinating interactions. The viscosity was reduced by introducing polyalcohol-based ILs, leading to polyamine-based hybrid ILs. Interestingly, these polyamine-based hybrid ILs exhibited high CO₂ capacity (4.09 mmol/g, 0.1 bar) at high temperature (80°C) and excellent reversibility in the presence of H₂O and O₂, which is superior to many other good absorbents. Moreover, these ILs also showed good performance for CO₂ capture from stimulated air (2.10 mmol/g, 380 ppm). We believe that this method with easy preparation, low cost, high efficiency and excellent reversibility has a great potential in the industrial capture of CO₂ from flue gas.     

光生物反应器对工业锅炉烟道尾气中二氧化碳的利用

比较了工业化光生物反应器培养微藻的3种主要CO2利用方式,阐述了工业锅炉烟道尾气所含多种重金属元素会在藻液中形成重金属离子,微藻在吸收CO2的同时也吸附重金属离子的机理.指出当重金属离子在藻液中积累到一定浓度时会造成光生物反应器的微藻生长系统崩溃,不能直接采用工业锅炉烟道尾气作为工业化封闭式光生物反应器培养微藻系统的碳源供给方式.     

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。     

功能化Zr-MOF强化混合基质膜CO2分离

混合基质膜（MMMs）在气体分离领域具有良好的应用前景,金属有机框架（MOFs）由于具有高孔隙率和有机连接基团,常被用作填料制备MMMs。但由于MOFs与聚合物的界面相容性问题,MMMs的气体分离性能提升受到限制。本文合成了功能化的Zr-MOF（UiO-66-AC）,并利用其与聚醚共聚酰胺（Pebax）共同制备了混合基质膜。填料中引入的羰基和羧基等基团提供了MOFs与聚合物基质之间较强的界面相互作用。与纯Pebax膜相比,UiO-66-AC/Pebax MMMs的气体渗透性能得到了显著提高。当填料质量分数为6%时,膜的CO₂渗透系数为102.4 Barrer,CO₂/N₂和CO₂/CH₄选择性分别为90.6和26.0,CO₂/N₂分离性能突破了Robeson上限(2008),表明该混合基质膜在CO₂的分离应用上具有潜力。     

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.     

Development of silica‐gel‐supported polyethylenimine sorbents for CO2 capture from flue gas

In order to reduce the sorbent preparation cost and improve its volume‐based sorption capacity, the use of an inexpensive and commercially available silica gel was explored as a support to prepare a solid polyethylenimine sorbent (PEI/SG) for CO₂ capture from flue gas. The effects of the pore volume and particle size of the silica gels, molecular weight of polyethylenimine and amount of polyethylenimine loaded, sorption temperature and moisture in the flue gas on the CO₂ sorption capacity of PEI/SG were examined. The sorption performance of the developed PEI/SG was evaluated by using a thermogravimetric analyzer and a fixed‐bed flow sorption system in comparison with the SBA‐15‐supported polyethylenimine sorbent (PEI/SBA‐15). The best PEI/SG sorbent showed a mass‐based CO₂ sorption capacity of 138 mg‐CO₂/g‐sorbent, which is almost the same as that of PEI/SBA‐15. In addition, the PEI/SG gave a high volume‐based sorption capacity of 83 mg‐CO₂/cm³‐sorbent, which is higher than that of PEI/SBA‐15 by a factor of 2.6. © 2011 American Institute of Chemical Engineers AIChE J, 58: 2495–2502, 2012     

普通小球藻固定模拟烟气中CO2的实验研究

大气中CO₂浓度增加造成的全球变暖已成为一个严峻的环境问题,利用微藻生物固碳法减排CO₂正成为研究热点.本文以普通小球藻(Chlorella vulgaris,FACHB-1227)为研究对象,采用SE无碳培养基,在沿程曝气型套管式光生物反应器中通入含不同体积分数CO₂(5%、10%、15%和20%)的模拟烟气培养小球藻,培养周期为17天,以细胞密度和平均固碳速率为检测指标,研究模拟烟气下普通小球藻生长情况及固碳能力.实验结果表明:当模拟烟气中CO₂体积分数为10%时,普通小球藻的细胞密度达到最大值8.76×10⁶cells/mL,相比于5%组、15%组和20%组分别提高了54.23%、66.86%和76.97%;其平均固碳速率达最大值30.18mg/(L·d),较5%组、15%组和20%组分别提高了57.27%、70.89%和81.91%.可见,在模拟烟气中CO₂体积分数为10%时,普通小球藻的生长情况和固碳性能最好.     

离子液体二氧化碳分离膜研究进展

离子液体支撑液膜在较大跨膜压差（0.25～0.3MPa）下的稳定性较差,具有较好稳定性的聚离子液体膜和离子液体-聚合物共混膜等逐渐被关注。本文综述了离子液体支撑液膜、聚离子液体膜、离子液体?聚合物共混膜等离子液体膜CO2分离性能、分离机理及稳定性的最新研究进展,介绍了无机颗粒-离子液体-聚合物共混膜的研究现状。指出离子液体膜的高CO2渗透通量与高稳定性之间的矛盾、共混膜结构调控难等问题是其工业化应用的主要障碍,提出开发新的膜材料、改进制膜工艺以减小膜厚、优化膜结构是提高膜的CO2渗透和分离性能,并保持膜稳定性的有效途径。无机颗粒-离子液体-聚合物共混膜兼有较高的CO2分离性能和较好稳定性,具有良好的应用前景,对其制备方法、结构、性能及CO2分离机理的研究将成为这一领域的热点。     

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。     

Membranes for CO2 /CH4 and CO2/N2 Gas Separation

Membrane technology has emerged as a leading tool worldwide for effective CO₂ separation because of its well-known advantages, including high surface area, compact design, ease of maintenance, environmentally friendly nature, and cost-effectiveness. Polymeric and inorganic membranes are generally utilized for the separation of gas mixtures. The mixed-matrix membrane (MMM) utilizes the advantages of both polymeric and inorganic membranes to surpass the trade-off limits. The high permeability and selectivity of MMMs by incorporating different types of fillers exhibit the best performance for CO₂ separation from natural gas and other flue gases. The recent progress made in the field of MMMs having different types of fillers is emphasized. Specifically, CO₂/CH₄ and CO₂/N₂ separation from various types of MMMs are comprehensively reviewed that are closely relevant to natural gas purification and compositional flue gas treatment     

氧化钙-二氧化碳循环系统脱碳的分析研究

采用燃料氧燃烧直接供热的氧化钙-二氧化碳双床循环系统已经被研究开发,用于从电厂尾气中脱碳。本研究基于实验和化学反应工程原理建立了分析模型,用于系统地研究循环特征,氧化钙活性衰减,燃料及其炉内热利用率的影响。基于模型推导获得了重要参数:最小循环热损失和最小热需求量,以及对应的固体循环比。它们都受供热燃料灰分和含硫量的影响,也受脱碳率的影响。显然最佳固体循环比介于二者之间。另一个重要参数是燃料在炉内的热利用率。高的热利用率不仅降低燃料需求量,降低其灰分和含硫的影响,降低氧的需求量及其辅助功,而且提高蒸汽循环的发电效率。一个发现是热需求量在临界固体循环比接近无穷大,这就限制了固体循环比的可操作范围, 以及燃料的灰分和含硫量。建立的分析模型和推导直接提供了这些变量之间的关系和范围。