面向氢气/甲烷分离分子筛膜微结构调控的研究进展

氢能具有燃烧值高、零碳排放等优势,发展氢能技术是实现“碳达峰、碳中和”战略的重要举措。当前,基于天然气和石油路线的制氢均存在将氢气从甲烷等烃分子中分离的过程。氢气/甲烷分离主要有变压吸附法、深冷精馏法以及膜分离法。分子筛膜具有精准分子筛分、高分离性能和稳定性好等优势,是低能耗分离氢气/甲烷最具发展潜力的膜材料。面向氢气/甲烷分离的应用需求,阐述了沸石分子筛膜和MOFs分子筛膜微结构调控策略、氢气/甲烷分离性能和构效关系的研究现状,分析了分子筛膜材料在氢气/甲烷分离领域的机遇和挑战。绘制了可与2008年聚合物膜Robeson上限图相比的分子筛膜性能数据图,并预测了分子筛膜在制氢分离领域经济可行的分离性能目标区域。     

碳中和背景下工业副产气制氢技术研究与应用

我国工业副产气排放量大,在对环境造成污染的同时,副产气中H₂、CO等有效成分随排放而浪费。氢气既是重要的化工原料,也是无碳、高效的能源,用工业副产气制备或分离提纯氢气既减少资源浪费,又可减少CO₂排放。本文介绍了我国含氢工业副产气排放情况,详述了焦炉煤气制氢、炼厂副产气制氢、氯碱尾气制氢等三种典型工业副产气制氢工艺,对煤制氢、天然气制氢、甲醇制氢及三种典型工业副产气制氢工艺的成本和CO₂排放进行了计算和整理分析。文章指出,考虑二氧化碳排放和碳交易成本等因素,与煤制氢、天然气制氢、甲醇制氢和电解水制氢相比,现阶段下工业副产气制氢的综合成本优势更加明显。在碳中和背景下,工业副产气制氢是获取低碳氢气的有效和经济的途径,研究和开发工业副产气制氢技术,将为碳减排提供一条高效路径。     

用于甲烷-氮气体系分离的膜技术研究进展

天然气作为一种高效、清洁的化石能源,在我国能源转型中扮演着重要角色。部分常规和非常规天然气含有较高浓度的氮气,会降低天然气的热值,无法满足管道输送的要求[氮气含量小于4%(体积分数)]。因此,天然气脱氮对实现化石能源的高效利用具有重要意义。相比于传统的气体分离技术,膜分离技术具有操作弹性大、投资少、能耗低等优点,在能源和环境领域均展现出广阔的应用前景。介绍了甲烷-氮气分离膜的传递机理,从甲烷优先渗透膜、氮气优先渗透膜两方面综述了甲烷-氮气膜分离技术的研究进展,同时针对不同的应用场合(常规天然气、页岩气和煤层气)进行了膜过程模拟研究,结合应用实例展望了膜技术在甲烷-氮气分离领域的发展及应用前景。     

一步法制备含氨基化合物的非对称CO2分离膜

采用一步相分离法,制备以聚醚砜（PES）为主体材料,二乙醇胺（DEA）为添加剂和氨基载体的膜,用于CO₂分离。考察了PES浓度、DEA浓度、膜厚度对CO₂/N₂分离性能的影响,同时考察了膜性能的长时间稳定性。当涂膜液中DEA/PES的质量比为12/26、刮刀与无纺布的距离为300 μm、进料气压力为0.11 MPa（表压）时,膜的CO₂渗透速率可达274 GPU,CO₂/N₂分离因子可达50。测试温度低于40℃时,DEA/PES膜的CO₂渗透速率和CO₂/N₂分离因子保持稳定。另外,对CO₂/N₂分离性能较好的DEA/PES膜（质量比为12/27）进行CO₂/CH₄分离性能测试,在1 MPa（表压）下性能优于商品膜。上述结果表明,本文研制的DEA/PES膜制备步骤简单,易于规模化制备,性能较优,在CO₂分离领域具有良好的应用前景。     

Promotion of hydrogen permeation on metal-dispersed alumina membranes and its application to a membrane reactor for methane steam reforming

A mesoporous membrane for selective separation of hydrogen was prepared usingthe sol-gel method. Some metal salts such as RuCl₃, Pd(NH₃)₄Cl₂, RhCl₃,, and H ₂PtCl₆, were added to the boehmite sol and coated on a porous alumina substrate before firing at 500°C. It was foundthat the permeability of hydrogen and the separation factor for a hydrogen-nitrogen gaseous mixture of these metaldispersed membranes exceeded the limitations of the Knudsen diffusion mechanism. Although the gas permeation through a neat alumina membrane is governed by the Knudsen diffusion, the metals dispersed in alumina membranes were effective in promoting hydrogen permeation. These metaldispersed alumina membranes were also used in a membrane reactor for methane steam reforming at low temperature. In the temperature range of 300 to 500°C, the membrane reactor attained a methane conversion twice as high as the equilibrium value of the packed bed catalytic reactor system as a result of the selective removal of hydrogen from the reaction system.     

用于生物气提纯的促进传递膜

由生物气提纯获得的生物甲烷具有高热值,可作为天然气的替代品。生物气中除主要成分甲烷以外还含有大量的CO₂和少量的水、H₂S以及其他痕量杂质组分,需经过净化提纯方可获得高纯度的生物甲烷。膜分离技术用于生物气提纯具有绿色、高效、能耗低等特点,特别地,促进传递膜因其特殊的传质机制,对于生物甲烷系统提纯具有显著优势。综述了促进传递膜材料及其制备技术,讨论了生物气中水、H₂S杂质对膜过程的影响,同时尝试对膜法生物气提纯的经济性和发展前景进行了分析。     

Nickel(II) ion-intercalated MXene membranes for enhanced H2/CO2 separation

Hydrogen fuel has been embraced as a potential long-term solution to the growing demand for clean energy. A membrane-assisted separation is promising in producing high-purity H₂. Molecular sieving membranes (MSMs) are endowed with high gas selectivity and permeability because their well-defined micropores can facilitate molecular exclusion, diffusion, and adsorption. In this work, MXene nanosheets intercalated with Ni²⁺ were assembled to form an MSM supported on Al₂O₃ hollow fiber via a vacuum-assisted filtration and drying process. The prepared membranes showed excellent H₂/CO₂ mixture separation performance at room temperature. Separation factor reached 615 with a hydrogen permeance of 8.35 × 10⁻⁸ mol·m⁻²·s⁻¹·Pa⁻¹. Compared with the original Ti₃C₂T_x/Al₂O₃ hollow fiber membranes, the permeation of hydrogen through the Ni²⁺-Ti₃C₂T_x/Al₂O₃ membrane was considerably increased, stemming from the strong interaction between the negatively charged MXene nanosheets and Ni²⁺. The interlayer spacing of MSMs was tuned by Ni²⁺. During 200-hour testing, the resultant membrane maintained an excellent gas separation without any substantial performance decline. Our results indicate that the Ni²⁺ tailored Ti₃C₂T_x/Al₂O₃ hollow fiber membranes can inspire promising industrial applications.     

分子筛基CH4-N2分离材料的研究进展

实现CH₄-N₂高效分离能够极大地推动常规天然气和非常规天然气这一类绿色低碳能源的利用,分子筛基吸附剂和膜材料具有优良的气体分离特性,而且对CH₄-N₂的分离颇具应用潜力。本文从对N₂具有优先选择性吸附的N₂/CH₄分离（高浓度CH₄纯化脱氮）和对CH₄具有优先选择性吸附的CH₄/N₂分离（低浓度CH₄富集脱氮）两方面综述了国内外分子筛吸附剂及分子筛膜的研究进展。详细地分析了分子筛骨架和平衡阳离子与其CH₄-N₂吸附分离性能之间的构效关系,并结合本文作者课题组的工作,提出了电中性（近中性）骨架分子筛对CH₄-N₂分离具有较好的分离效果。最后总结和展望了CH₄-N₂分离用分子筛吸附剂及分子筛膜的未来发展趋势。     

An effective strategy to boost hydrogen separation performance through stable mixed proton-electron conducting membrane

Hydrogen separation and purification are key to widespread application of hydrogen energy. Hydrogen permeable membranes based on lanthanum tungstate (LWO) attract attention due to favorable mechanical strength and chemical stability. However, industrial application of LWO-based membranes has remained challenging because of modest hydrogen permeances. Here we report a novel graded porous supported symmetric (GPSS) LWO-based membrane with improved transport properties, gas exchange dynamics, and operational stability, boosting stable hydrogen flux by several times over previously reported state-of-the-art membranes.     

新型超临界水中煤气化制氢产物的CO2分离过程

目前CO₂的分离方式主要局限在常压条件下,在高压条件下分离CO₂的研究鲜有报道。本文为了解决这一问题,针对煤在超临界水中气化过程压力高的特点,构建了高压水吸收法分离CO₂系统,建立了高压多组分气液相平衡的能量分析模型和 分析模型;并对CO₂的分离过程进行分析,获得了高压吸收器中压力对各种气体产物摩尔分数和液相中气体吸收率的影响规律;针对高压水吸收法分离CO₂的流程,建立了CO₂分离过程中的能量分析模型和 分析模型,得到了高压吸收器中压力发生变化时,CO₂分离过程的能量效率、 效率以及CO₂分离能耗的变化规律,为超临界水中煤气化制氢新技术中分离器的设计提供了依据。     

石墨烯基材料在CO2分离膜领域的研究进展

节能高效的CO₂分离技术的开发具有重要的现实及长远意义,膜法CO₂分离在该领域备受关注,具有优异传质特性的新型分离膜材料对膜分离过程有决定性的影响。近年来,石墨烯及其衍生材料因独特的单原子层厚度、亚纳米级别的孔道结构以及优异的机械、化学和热稳定性,成为气体分离膜领域的研究热点,膜的加工难度、技术成本、大面积制备、工作稳定性等问题是限制其实际应用的关键因素。石墨烯基CO₂分离膜主要有三种形式：纳米孔石墨烯膜、层状结构氧化石墨烯膜、基于石墨烯及其衍生材料的混合基质膜。本文综述了石墨烯基CO₂分离膜领域的突破性研究进展,重点介绍了气体的跨膜传质机理和膜的构性关系,总结了膜性能的优化思路和原理,梳理了石墨烯基CO₂分离膜发展面临的挑战,提出了潜在的研究方向。分析表明,进行系统的理论研究,采用先进的表征手段,以建立膜构性关系的理论模型,指导膜结构设计是未来研究的重点。此外,进一步降低膜加工成本,充分研究膜在实际工作环境中的稳定性也至关重要。     

煤层气回收及CH4/N2分离PSA材料的研究进展

我国煤层气蕴藏丰富,在面临能源危机时代煤层气可作为天然气能源的有效补充。本文介绍了低浓煤层气回收即CH₄/N₂分离几种常见技术：低温技术、水合物技术、溶解技术、膜分离和变压吸附技术（PSA）的分离原理、技术开发和研究的现状,并分析了各项技术目前存在的问题。讨论了多孔材料,如活性炭、碳分子筛、沸石分子筛和新型金属有机骨架材料（MOFs）等对CH₄/N₂吸附分离效果的研究进展,由于MOFs材料的吸附性能随温度或压力的改变出现飞跃,预示了其在PSA领域广阔的应用前景。     

储氢提纯和氢网络的耦合优化

基于氢网络的集成以及AB₅型储氢材料LaNi_4.75Fe_0.25及LaNi_4.85Al_0.15的特性,对储氢提纯在氢网络中的应用进行研究。综合考虑LaNi_4.75Fe_0.25及LaNi_4.85Al_0.15储氢/放氢动力学,建立了储氢提纯氢网络的优化方法,根据单位质量储氢材料提纯的节氢能力和公用工程节省量与提纯参数的关系,确定最优提纯氢源浓度、最大公用工程节省量、储氢材料量和吸氢时间。用该方法对某炼厂氢网络和储氢提纯单元进行优化,结果表明,最优提纯氢源浓度为70%,提纯后公用工程可节省23.72%; LaNi_4.85Al_0.15作为储氢提纯材料优于LaNi_4.75Fe_0.25,其消耗量为991.26 kg。     

Comparative study on pressure swing adsorption system for industrial hydrogen and fuel cell hydrogen

In order to improve the design of PSA system for fuel cell hydrogen production, a non-isothermal model of eight-bed PSA hydrogen process with five-component (H₂/N₂/CH₄/CO/CO₂=74.59%/0.01%/4.2%/2.5%/18.7% (vol)) four-stage pressure equalization was developed in this article. The model adopts a composite adsorption bed of activated carbon and zeolite 5A. In this article, pressure variation, temperature field and separation performance are stimulated, and also effect of providing purge (PP) differential pressure and the ratio of activated carbon to zeolite 5A on separation performance in the process of producing industrial hydrogen (CO content in hydrogen is 10 μl·L^-1) and fuel cell hydrogen (CO content is 0.2 μl·L^-1) are compared. The results show that Run 3, when the CO content in hydrogen is 10 μl·L^-1, the hydrogen recovery is 89.8%, and the average flow rate of feed gas is 0.529 mol·s^-1; When the CO content in hydrogen is 0.2 μl·L^-1, the hydrogen recovery is 85.2%, and the average flow rate of feed gas is 0.43 mol·s^-1. With the increase of PP differential pressure, hydrogen recovery first increases and then decreases, reaching the maximum when PP differential pressure is 0.263 MPa; With the decrease of the ratio of activated carbon to zeolite 5A, the hydrogen recovery increases gradually. When the CO content in hydrogen is 0.2 μl·L^-1 the hydrogen recovery increases more obviously, from 83.96% to 86.37%, until the ratio of activated carbon to zeolite 5A decreases to 1. At the end of PP step, no large amount of CO₂ in gas or solid phase enters the zeolite 5A adsorption bed, while when the CO content in hydrogen is 10 μl·L^-1, and the ratio of carbon to zeolite 5A is less than 1.4, more CO₂ will enter the zeolite 5A bed.     

High-performance SSZ-13 membranes prepared using ball-milled nanosized seeds for carbon dioxide and nitrogen separations from methane

SSZ-13 membranes with high separation performances were prepared using ball-milled nanosized seeds by once hydrothermal synthesis. Separation performances of SSZ-13 membranes in CO_2/CH_4 and N_2/CH_4 mixtures were enhanced after synthesis modification. Single-gas permeances of CO_2, N_2 and CH_4 and ideal selectivities were recorded through SSZ-13 membranes. The effects of temperature, pressure, feed flow rate and humidity on separation performance of the membranes were discussed. Three membranes prepared after synthesis modifications had an average CO_2 permeance of 1.16 × 10~(-6) mol·(m~2· s·Pa)~(-1)(equal to 3554 GPU) with an average CO_2/CH_4 selectivity of 213 in a 50 vol%/50 vol% CO_2/CH_4 mixture. It suggests that membrane synthesis has a good reproducible. The membrane also displayed a N_2 permeance of 1.07 × 10~(-7) mol·(m~2·s·Pa)~(-1)(equal to 320 GPU) with a N_2/CH_4 selectivity of 13 for a 50 vol%/50 vol% N_2/CH_4 mixture. SSZ-13 membrane displayed stable and good separation performance in the wet CO_2/CH_4 mixture for a long test period over 100 h at 348 K. The current SSZ-13 membranes show great potentials for the simultaneous removals of CO_2 and N_2 in natural gas purification as a facile process suitable for industrial application.     

界面聚合法制备用于脱氮提纯CH4的N2优先渗透ZIF-90/聚酰胺混合基质膜

作为一种高效的分离方法,膜法分离非常规天然气具有较理想的应用前景。相较CH₄优先渗透膜,N₂优先渗透膜优势在于分离N₂/CH₄混合气后CH₄处于高压侧,利于后续处理。以均苯三甲酰氯为油相单体,间苯二胺为水相单体,采用界面聚合法在聚砜基膜上制备致密超薄聚酰胺分离层,并通过向其中引入孔径可允许N₂分子通过而不允许CH₄分子通过的纳米颗粒ZIF-90,在膜内形成固定的N₂传递通道,成功制备了用于脱氮提纯CH₄的N₂优先渗透混合基质膜。膜渗透选择性能测试结果显示当混合基质膜中纳米颗粒掺杂量为0.30 g·L^-1时,2 bar（1 bar=0.1 MPa）进料压力下,N₂渗透速率达1.16×10^-9 mol·m^-2·s^-1·Pa^-1,N₂/CH₄分离因子达16.6,分离因子比未掺杂ZIF-90的聚酰胺膜提高46.5%,具有一定的处理非常规天然气脱氮提纯甲烷的应用潜力。     

界面聚合法制备用于脱氮提纯CH4的N2优先渗透ZIF-90/聚酰胺混合基质膜

作为一种高效的分离方法,膜法分离非常规天然气具有较理想的应用前景。相较CH₄优先渗透膜,N₂优先渗透膜优势在于分离N₂/CH₄混合气后CH₄处于高压侧,利于后续处理。以均苯三甲酰氯为油相单体,间苯二胺为水相单体,采用界面聚合法在聚砜基膜上制备致密超薄聚酰胺分离层,并通过向其中引入孔径可允许N₂分子通过而不允许CH₄分子通过的纳米颗粒ZIF-90,在膜内形成固定的N₂传递通道,成功制备了用于脱氮提纯CH₄的N₂优先渗透混合基质膜。膜渗透选择性能测试结果显示当混合基质膜中纳米颗粒掺杂量为0.30 g·L^-1时,2 bar（1 bar=0.1 MPa）进料压力下,N₂渗透速率达1.16×10^-9 mol·m^-2·s^-1·Pa^-1,N₂/CH₄分离因子达16.6,分离因子比未掺杂ZIF-90的聚酰胺膜提高46.5%,具有一定的处理非常规天然气脱氮提纯甲烷的应用潜力。     

Fabrication of Thin-Film SrCe0.9Eu0.1O3−δ Hydrogen Separation Membranes on Ni–SrCeO3 Porous Tubular Supports

SrCe_0.9Eu_0.1O_3−δ thin-film (∼30 μm) tubular hydrogen separation membranes were developed in order to obtain high hydrogen fluxes. Fifteen centimeters long, one end closed, NiO–SrCeO₃ tubular supports were fabricated by tape casting, followed by rolling the green tape on a circular rod. SrCe_0.9Eu_0.1O_3−δ powders were prepared by the citrate process and coated on partially sintered NiO–SrCeO₃ tubular supports. Leakage-free hydrogen membrane cells were obtained by adjusting the presintering and final sintering temperatures to reduce the difference of linear shrinkage rates between SrCe_0.9Eu_0.1O_3−δ thin films and NiO–SrCeO₃ supports. A hydrogen flux of 2.2 cm³/min was obtained for the SrCe_0.9Eu_0.1O_3−δ on Ni–SrCeO₃ tubular hydrogen separation membranes at 900°C using 25% H₂ balanced with Ar and 3% H₂O as the feed gas and He as the sweep gas. Thus, a 40% single pass yield of pure H₂ was achieved with this membrane.     

Nano-confined ammonia borane for chemical hydrogen storage

There is a great demand for a sufficient and sustainable energy supply. Hence, the search for applicable hydrogen storage materials is extremely important owing to the diversified merits of hydrogen energy. In this regard, ammonia borane (NH₃BH₃, AB) containing 19.6 wt-% hydrogen has been considered as a promising material for hydrogen storage applications to realize the “hydrogen economy”, but with limits from slow kinetics of hydrogen release and by-product of trace gases such as ammonia and borazine. In this review, we introduce the recent research on AB, regarding to the nanoconfinement effect on improving the kinetics at a relatively low temperature and the prevention/reduction of undesirable gas formation.     

天然气脱碳技术研究进展

天然气是一种高燃烧热值的清洁能源,但开采出来的天然气中含有一定量的酸性气体CO₂,会造成热值降低、管道腐蚀等问题,因此在管道运输和使用前需对其进行脱碳处理。分别对低温精馏、溶剂吸收、吸附和膜分离四种脱碳技术进行了介绍,详析了每一种技术的工艺特点和典型工业应用情况,并从原料气进料条件、脱碳效率、能耗及成本等方面进行了分析比较,为不同实际工况脱碳工艺的选择提供指导,具有重要的工程意义。膜分离技术在装置占地面积、能耗及成本等方面具有一定优势,可灵活调变的级数工艺也使其能够实现高CO₂脱除率和低烃损失,具有良好的发展和应用前景,特别是适用于空间受限的场合,如在海上平台进行天然气脱碳处理。