PPESK中空纤维复合膜对丙烯／丙烷分离性能的研究

以含二氮杂萘联苯结构的聚芳醚砜酮PPESK（Tg263—305℃）为膜材料,以干-湿相转化法制备中空纤维基膜,采用内涂法涂覆聚乙烯基吡咯烷酮（PVP）,并配合Ag＋,制备了促进输送中空纤维复合膜。研究了复合膜聚电解质涂敷时间、2次涂层、不同银盐以及不同过渡金属离子等对复合膜丙烯／丙烷分离性能的影响。实验结果表明．室温下,n（Ag＋）：n（C=O）=1：1,涂敷时间为10min时,复合膜对丙烯／丙烷的分离性最好,PVP／AgNO3体系分离系数为3．98,PVP／AgBF4体系的分离系数为5．69。经过2次涂敷后,PVP／AgNO3体系的分离系数升高至4．20,PVP／Ag-BF4体系的分离系数升高至10．78。由此可见,相同条件下,AgNO3的促进传递效果明显低于AgBF4。     

丙烷脱氢制丙烯低温分离工艺分析

为确立丙烷脱氢制丙烯工艺中低温分离单元的最佳制冷流程,采用PRO/Ⅱ8.2化工流程模拟软件,对低温分离单元进行模拟计算,考察了温度和压力对低温分离效果的影响,分析并确立了最佳分离温度和压力范围;在分离效果相同的前提下,分别比较了丙烯+乙烯级联制冷、丙烯预冷+混合制冷和丙烯预冷+富氢气膨胀制冷3种制冷流程的公用工程消耗以及各自的优缺点。结果表明:产品压缩机出口压力对分离效果影响较小,在确保下游装置能够正常操作的情况下,分离压力应尽可能低;分离温度是影响分离效果的主要因素,较为经济的分离温度为-90—-100℃;相对于其他2种流程,丙烯+乙烯级联制冷流程具有技术成熟、能耗低和操作简单等优点,更适合于丙烷脱氢制丙烯工艺。     

丙烷脱氢制丙烯研究新进展

介绍了丙烷催化转化制丙烯的研究状况,综述了丙烷催化脱氢制丙烯的铬系催化剂、铂系催化剂及其助剂Sn的研究进展;评述了丙烷氧化脱氢反应机理低温和高选择性的催化剂及膜反应器在丙烷脱氢反应上所具有的优越性,认为研发具有高稳定性和高透氢性能的氢分离膜,将有望能大幅度提高丙烯的收率。     

丙烷脱氢制丙烯技术研究

介绍了催化脱氢、氧化脱氢、膜反应器脱氢等几种丙烷脱氢制丙烯技术,综述了丙烷催化脱氢制丙烯催化剂的研究现状,虽然丙烷催化脱氢生产丙烯已实现了工业化,但其催化剂的性能需进一步提高;对丙烷氧化脱氢制丙烯反应催化剂的研究现状及膜反应器在丙烷脱氢反应上所具有的优越性进行了描述,认为研发具有高稳定性和高透氢性能的氢分离膜,将有望能大幅度提高丙烯的收率。     

丙烷脱氢制丙烯技术研究

介绍了几种丙烷脱氢制丙烯技术：催化脱氢、氧化脱氢、膜反应器脱氢。综述了丙烷催化脱氢制丙烯催化剂的研究现状，虽然丙烷催化脱氢生产丙烯虽已实现了工业化，但其催化剂的性能需进一步提高；综述了丙烷氧化脱氢制丙烯反应催化剂的研究现状及膜反应器在丙烷脱氢反应上所具有的优越性，认为研发具有高稳定性和高透氢性能的氢分离膜，将有望能大幅度提高丙烯的收率。     

丙烯/丙烷分离的ZIF-8膜研究进展

同碳数烯烃/烷烃的分离是目前石油化工行业中最耗能的过程之一,开发新型的、低能耗的丙烯/丙烷分离过程被认为是改变世界的七项化工分离技术之一。气体膜分离技术因其高效、节能和环境友好等优点被认为是一种可取代传统低温精馏分离丙烯/丙烷混合气体的新型技术。金属有机骨架材料ZIF-8的有效孔径介于丙烯和丙烷的分子动力学直径之间,可对丙烯/丙烷实现高效分离,是目前分离丙烯/丙烷性能最好的膜材料。本文系统总结了ZIF-8膜的制备方法及用于丙烯/丙烷高效分离的发展历程;探讨了ZIF-8膜微结构的调控,尤其是膜缺陷的修复及ZIF-8骨架柔性的控制;总结了ZIF-8膜在分离丙烯/丙烷时,过程参数对于分离性能的影响规律;并提出ZIF-8膜规模化制备及潜在工业分离丙烯/丙烷研究中存在的问题和未来发展方向。     

芳烃官能化有机硅膜的制备及丙烯/丙烷分离性能

利用具有单苯和联苯桥联结构的有机硅前体1,4-二(三乙氧基硅基)苯(BTESB)和4,4’-二(三乙氧基硅基)联苯(BTESBPh),通过溶胶-凝胶法制备成有机硅膜并应用于丙烯/丙烷分离。在25℃时,BTESB膜的C₃H₆渗透速率为3.4×10^-9mol/(m²·s·Pa),C₃H₆/C₃H₈选择性为9.6;BTESBPh膜的C₃H₆渗透速率为1.7×10^-8mol/(m²·s·Pa),C₃H₆/C₃H₈选择性为10.5。具有联苯桥联结构的BTESBPh膜网络结构更为疏松,可获得更高的气体渗透速率。苯环中大π键与待分离组分C₃H₆中的碳碳双键产生π-π相互作用,有利于C₃H<...     

多级孔ZSM-5分子筛的制备及其丙烷脱氢制丙烯的催化性能

采用不同浓度的四乙基氢氧化铵(TEAOH)溶液处理HZSM-5分子筛,并通过XRD、XRF、H2化学吸附、吡啶红外吸附(FT-IR)和N2低温物理吸附对样品进行表征分析,考察有机碱溶液对载体和催化剂物化性能的影响。表征结果显示,低浓度的TEAOH溶液处理HZSM-5后形成介孔-微孔多级孔道结构,介孔容积和外比表面积明显增加,进而提高催化剂表面Pt金属裸露度;高浓度有机碱处理则能够明显增加分子筛表面酸性,同时引起催化剂表面Pt分散度下降。采用有机碱处理后的载体上制备了Pt-Sn-Na/HZSM-5催化剂,并在固定床反应器上考察了丙烷脱氢制丙烯的催化活性。结果表明,随着有机碱溶液的增加,丙烷初始转化率逐渐增加,丙烯选择性则逐渐下降,稳定性呈现出先增加后减少的趋势。以20 mol·L-1有机碱溶液处理HZSM-5分子筛为载体制备的催化剂用于丙烷脱氢活性评价显示,反应120 h后丙烷化率为34.93%,丙烯选择为98.67%,该催化剂脱氢活性和稳定性较佳。     

大型丙烷脱氢装置丙烯压缩机的工艺方案研究

丙烷脱氢制丙烯因其原料易得、廉价和工艺流程短,已成为重要的丙烯生产技术。丙烯制冷压缩机是丙烷脱氢的重要设备之一,它的优化设计对降低丙烷脱氢的能耗具有重要意义。本文采用Aspen Plus模拟软件,对600 kt/a丙烷脱氢装置配套丙烯压缩机的8种可能工艺流程进行研究,最终提出了优化的节能设计方案。本研究为今后丙烯压缩机工艺流程的优化设计提供了重要的依据。     

丙烷丙烯分离塔操作优化研究

介绍了丙烯的生产工艺方法,利用化工软件的模拟计算结合实际生产标定探索丙烷丙烯分离塔的操作优化,并分析了丙烷丙烯分离塔生产波动的原因,提出了操作优化方案。     

Effects of coating solvent and thermal treatment on transport and morphological characteristics of PDMS/Torlon composite hollow fiber membrane

A new approach for formation of the polydimethylsiloxane (PDMS) layer on Torlon polyamide‐imide hollow fiber (PAI‐HF) support has been developed by directly after fiber spinning without the need to undergo the final conventional solvent exchange and drying step, thereby saving postspinning processing steps. The produced PDMS/PAI‐HF composite membranes were found to have high CO₂ permeance (i.e., 1100 GPU) and exhibited good CO₂/N₂ selectivities of 8–10 which is close to 90% of that of a PDMS dense film. The effects of coating solution, rewetting and crosslinking temperature on the PAI‐HF morphological features, that is, gas transport, skin thickness, skin integrity, and substructure resistance are investigated. The rewetting and thermal treatment of the PAI‐HF caused the densification of the skin layer and reduced the pore sizes on the top layer. In addition, the potential use of the PAI‐HF support with polymers that are insoluble in hexane is also considered. Effects of water, methanol, and hexane exposure of PAI‐HF to these solvents are considered. This evaluation calls attention to issues that must be addressed in any eventual use of the PAI‐HF with water‐soluble or methanol‐soluble selective layer polymers, rather than simple hexane‐soluble polymers such as PDMS. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45418.     

聚偏氟乙烯中空纤维膜的开发与应用进展

介绍了中空纤维膜的性能,生产的主要技术工艺与最佳的操作条件及有关进展情况。阐述了国内外研究开发的现状与发展趋势,并探讨了扩大应用范围等的前景与市场需求。     

Pervaporative separation of butanol using a composite PDMS/PEI hollow fiber membrane

In the study, the separation and purification of butanol was carried out using the composite hollow fiber membrane having the active layer of polydimethylsiloxane (PDMS) on the macroporous support of polyetherimide (PEI). The pervaporation results with the initial butanol concentration showed a trade-off between flux and separation factor. However, both the flux and the separation factor increased as the operating temperature increased. The pervaporation results showed the butanol flux and the separation factor were higher than those of the reported results. In this study, butanol was concentrated by the pervaporation as a feasibility study for the biofuel applications.     

气体分离用聚砜中空纤维膜的活化涂敷技术

主要探讨了一些表面活性剂对气体分离用聚砜中空纤维膜表面涂敷上的作用。结果表明 ,其中TO 80对提高H2 /N2 分离系数的效果最佳。     

Cu(I)-Based Ionic Liquids as Potential Absorbents to Separate Propylene and Propane

The absorption of propylene and propane in Cu(I)-based ionic liquids, i.e., 1-butyl-3-methylimidazolium chloride/CuCl ([Bmim][Cl]/CuCl), N-Methyl pyrrolidone chloride/CuCl ([HNMP][Cl]/CuCl), and tricaprylmethylammonium thiocyanate/CuSCN ([A336][SCN]/CuSCN), are investigated in this work. It is observed that such Cu(I)-based ionic liquids, especially Bmim-based ionic liquids, present good absorption capability for propylene and good selectivity over propane, e.g., 1.0 kilogram [Bmim][Cl]/CuCl is able to absorb 0.08 mol propylene while only 0.006 mol propane at 25°C and 1.3 bar with the selectivity of 13. The effects of pressure, Cu⁺ concentration, and temperature on the absorption are investigated; in addition, the absorption kinetics of propylene by [Bmim][Cl]/CuCl is obtained. The much higher absorption capability for propylene than propane is ascribed to the π-complexation between propylene and Cu⁺. This work shows that the absorption by Cu(I)-based ionic liquids is an potential alternative method for traditional cryogenic distillation with high energy cost to separate propylene and propane.     

Preparation and Characterization of C60‐Filled Ethyl Cellulose Mixed‐Matrix Membranes for Gas Separation of Propylene/Propane

Mixed‐matrix membranes (MMMs) consisting of ethyl cellulose as continuous matrix and inorganic particle C₆₀ as dispersed phase were prepared for propylene/propane separation. The impact of the C₆₀ content on the separation properties of MMMs without and with ultraviolet cross‐linking was investigated. The increment of decomposition temperature and single glass temperature of ethyl cellulose/C₆₀ MMMs indicates a strong interfacial interaction between polymer and fullerenes. After UV irradiation, the gas permeability coefficient of propylene and ideal separation factor of propylene/propane decreased, and new features appeared in scanning electron microscopy and atomic force microscopy images, testifying the photopolymerization reaction of C₆₀ at a depth near to the surface. C₆₀ could be acted as a possible replaced carrier for the separation of olefin/paraffin using membrane separation technology.