糠醇单体制备支撑炭分子筛膜

使用糠醇单体在多孔氧化铝管的内表面成功制备了炭分子筛膜。其制备采用了3种方法:(Ⅰ)将酸性催化剂加入到糠醇中使糠醇聚合,然后采用浸渍法涂膜;(Ⅱ)先将催化剂浸渍在支撑体上,然后将支撑体浸入到糠醇溶液中制膜;(Ⅲ)先将催化剂浸渍在支撑体上,然后将支撑体置于糠醇蒸汽中制膜。方法Ⅱ制备的炭膜质量最大。方法Ⅲ制备的炭膜质量次之,方法Ⅰ制备的炭膜质量最小。方法Ⅲ制得的炭膜具有最好的气体选择性,CO2/N2的理想选择性为79.3,O2/N2的理想选择性为10.6,方法Ⅰ、Ⅱ制得的炭膜的气体分离性能相近,CO2/N2的理想选择性为20,O2/N2的理想选择性为6。     

聚糠醇薄膜的热解动力学研究

采用热重法分析了聚糠醇薄膜在氮气氛围下的热解过程。结果表明,聚糠醇薄膜热解过程分为三个阶段,其中第二个阶段（160℃～480℃）为主要热分解阶段,同时也对聚糠醇薄膜在主要热解区间的热解反应动力学进行研究,显示聚糠醇薄膜在主要热解区间内的热解反应是分段进行的,均为一级反应,在不同热解阶段发生的热解反应分别具有不同的活化能和频率因子。     

聚糠醇自支撑膜界面法合成条件的探讨

采用界面自组装聚合法,首次成功地制备出聚糠醇自支撑膜。利用SEM、TEM、FT-IR及TG-DTA技术对其形貌、结构等进行了表征,并考查了催化剂种类以及表面活性剂用量对其形貌的影响。结果表明,由该法可以合成聚糠醇自支撑膜,并且通过改变催化剂的种类及表面活性剂的用量可以得到不同形貌的材料。该法具有合成条件温和、易于控制、纯化简单、省去了使用模板、消除模板的过程,能够一步合成出大量聚糠醇自支撑膜等众多优点。     

气体分离用管状炭分子筛膜

以无机陶瓷管为支撑体、热塑性酚醛树脂为原料,经高温炭化制备了炭分子筛膜。用低温N2吸附的方法测定了炭分子筛膜的比表面积,用扫描电子显微镜对膜的形貌和厚度进行了表征。考察了膜的气体透过率以及气体的理想选择性随温度的变化关系:H2、CO2、O2、N2和CH4的透过率随温度的升高而增大;理想选择性α(H2/N2)、α(CO2/N2)、α(CO2/CH4)随温度的升高而减小,而α(O2/N2)随温度的升高先增大后减小,在90℃左右气体选择性达到最大。最后由阿累尼乌斯公式计算了气体透过炭分子筛膜的活化能,进一步说明气体透过机理为活化扩散。     

炭分子筛膜研究的新进展

炭分子筛膜是一种用于气体分离的高效，节能的新型材料，具有好的气体分离选择性，高的热和化学稳定性，近年来得到国内外广泛的重视和发展，本文从制备炭分子筛膜的原料，制备工艺及其在气体分离应用等方面综合了国内外近年来炭分子筛膜的研究进展，并指出了目前存在的问题。     

炭分子筛膜气体分离传递机理研究的新进展

炭分子筛膜由于其本身具备的独特优势以及其在气体分离方面的应用潜力,已引起了世人的关注.但对炭分子筛膜分离机理特别是传递过程机理研究的不足限制了其发展.本文介绍炭分子筛膜气体分离机理特别是传递过程机理研究的最新进展,包括针对制备方法不同所建立的气体传递机理模型,如Maxwell模型和Bruggeman模型;详细介绍了两种孔结构模型平行阻力模型和阻力串联模型.在此基础上,分析了各模型中存在的问题和不足,认为需要对炭分子筛膜进行进一步的完善并建立合理的传递机理模型,才能推动炭分子筛膜用于气体分离的进程.     

炭膜气体分离性能研究

以酚醛树脂为原料制备了炭支撑膜和炭－炭复合膜，研究了其气体分离性能。结果表明：炭支撑膜分离气体和机理包括努森扩散和粘性流；采用浸涂－干燥－炭化的工艺制备的炭－炭复合膜对Ｈ２／ＣＯ２具有较好的分离性能，Ｈ２／ＣＯ２分离系数达５．６，大于理想努森扩散的分离系数３．７。但在高压差时复合膜上ＣＯ２的表面扩散增强，使Ｈ２／ＣＯ２分离系数下降。     

炭膜研究的新进展

介绍了近年来炭膜研究的新进展，并对支撑炭膜的制备方法，分离机理，性能及应用前景等进行了综述。     

粘结剂对核桃壳基炭分子筛空分性能的影响

考察了三种粘结剂对产品炭分子筛空分性能的影响，表明在煤焦油粘结剂中添加少量造纸浆废液或聚乙烯醇有助于改善炭分子筛空分性能，并能减少其颗粒表面含尘量。     

炭分子筛膜的制备与改性

炭分子筛膜足近年来发展起来的高效、新型气体分离膜,具有良好的气体分离选择性,高的热和化学稳定性,但其气体分离选择性与气体渗透通量却不能同时达到很高的要求.综述了炭分子筛膜的制备材料,重点讨论了化学方法和物理方法对制备炭膜的前驱体进行改性,展望了炭分子筛膜的未来发展方向.     

离子液膜分离CO_2、H_2混合气体研究

选用离子液体[BMIM]Cl与NaBF_4在甲醇中反应制得[BMIM]BF_4,离子液体[BMIM]Cl经OH型阴离子交换树脂交换后再与甲酸进行中和制得[BMIM]HCOO。分别选用3种聚合物薄膜PVDF、PAN和PS,使其与4种离子液体[BMIM]BF_4、[BMIM]HCOO、[BMIM]PF_6和[BMIM]CH_3COO共制成12种支撑液膜。在30℃、40℃和50℃时分别进行12种液膜的CO_2、H_2单一气体渗透性测试。结果显示,[BMIM]BF_4型聚砜膜在30℃时对CO_2与H_2分离性能较好,分离系数达14以上;[BMIM]PF_6型聚丙烯睛膜在30℃时分离系数达12以上;[BMIM]PF_6型聚偏氟乙烯膜在30℃时分离系数达到5以上。因此这3种离子液膜在30℃时可对CO_2、H_2混合气体进行一定程度的分离。     

离子液膜法分离H_2、N_2混合气体研究

选取2种市售离子液体1-丁基-3-甲基咪唑四氟硼酸盐([BMIM]BF4)与1-丁基-3-甲基咪唑六氟磷酸盐([BMIM]PF6),另采用离子交换法合成出2种离子液体1-丁基-3-甲基咪唑甲酸盐([BMIM]HCOO)与1-丁基-3-甲基咪唑乙酸盐([BMIM]CH3COO)。将离子液体与膜分离法优点相结合,选取聚偏氟乙烯膜、聚砜膜和聚丙烯腈膜并用浸渍法制备离子液体支撑液膜。比较不同温度下不同类型离子液膜对H2/N2的分离系数发现,[BMIM]HCOO型聚砜膜和聚丙烯腈膜对H2/N2分离系数较大。温度条件显著影响分离效果:30℃时[BMIM]BF4型聚偏氟乙烯膜、[BMIM]HCOO型聚砜膜分离H2/N2能力较强,可分离掉N2获得H2;30℃时[BMIM]BF4型聚砜膜分离N2/H2能力较强,可分离掉H2获得N2。     

膜技术在含烃类气体分离中的研究及前景

气体膜分离技术在膜分离中占有相当的比重。简要介绍了气体膜分离技术的基本原理,并对天然气、沼气、炼厂气等含烃类气体的膜法处理技术与传统加工技术进行对比,突出了膜法的技术及经济优势。着重介绍了用于含烃气体处理的各种材质膜的研究以及应用现状,并对气体分离膜、膜组件的发展及应用前景进行的简单的阐述。     

Gas Separation by a Continuous Membrane Column

Abstract

The continuous membrane column provides a revolutionary new separation technique. In gaseous diffusion the continuous membrane column is used to separate as highly concentrated products both the most permeable and least permeable gases from a feed mixture of any composition. The main features of the column are countercurrent enrichment, high reflux and minimal backmixing. The new method eliminates the need for numerous interstage compressors and extensive product stream recycling found in conventional gaseous diffusion cascades.

Experiments are carried out for systems of C0₂-O₂, O₂2-N₂ (air), and CO₂-N₂ mixtures using continuous membrane columns made out of silicone rubber membrane. Also, a theoretical model is developed to interpret the experimental data. The agreement between theory and experiment is excellent. The maximum degree of separation can be achieved at total reflux. It is experimentally verified that the maximum degree of enrichment attainable by a conventional method can easily be exceeded without limit when a continuous membrane column is employed.

Finally, a comparative study has been conducted for a conventional gas permeator and a continuous membrane column.     

有机废气膜分离处理方法研究

有机废气一般具有易燃,易爆,毒性大,不溶于水,易溶于有机溶剂,难以处理的特点。主要阐述了膜分离法处理有机废气的具体方法。     

Predicting Separation of Lower Hydrocarbon from Natural Gas by a Nano‐Porous Membrane using Capillary Condensation

In the present work, the potential of a nano‐porous membrane for predicting the separation of lower hydrocarbons from natural gas by capillary condensation was explored. While a gas permeates through a capillary at a suitable pressure, the adsorbed layer may attain a thickness enough to fill the entire membrane pore. Poiseuille flow of the condensed phase follows. Our computed results have established that for a passage through a nano‐porous membrane, gas having lower condensation pressure condenses in the pores at a pressure which is about an order of magnitude lower than its vapor pressure at the concerned temperature. In the case of propane/methane and butane/methane binary mixtures, propane and butane are preferentially condensed and permeation rates up to 700 g mol/m² s bar for propane and 600 g mol/m² s bar for butane have been achieved at a temperature lower than the critical temperature of the permeating species and higher than the critical temperature of the non‐permeating species. Since methane has a much lower critical temperature than both propane and butane, it gets physically dissolved in the condensed phase of propane, butane in the case of propane/methane and butane/methane binary mixtures, respectively. An equation of state (EOS) approach has been adopted to calculate the fugacity of methane in the gas, as well as in the condensed phase, in order to estimate its solubility. The Peng‐Robinson equation of state was used. Computation of the separation factor for methane/propane and methane/butane was performed over a wide range of temperature, pressure, and gas composition. The separation factor which is expectedly a function of these variables ranged from 0.3–75 for methane/propane and 0.7–140 for methane/butane binary mixtures. It has been established that an acceptable degree of separation is achievable at moderate pressure and at low temperature for the removal of propane and butane from natural gas. The results have the potential to be used for further refinement and optimization of the process conditions so that this strategy can be exploited for large‐scale removal of lower hydrocarbon from natural gas at a low cost.     

轻烃三一段纯氧转化制甲醇合成气的自然增碳研究

为达到甲醇合成的化学当量比,采用三一段纯氧自热转化工艺,即原料气分3路进行换热蒸汽转化、外热蒸汽转化和直入二段炉的蒸汽转化串纯氧自热转化方法,实现自然增碳的目的。对比了天然气制甲醇一段法与三一段纯氧转化法工艺的基本原理和工艺流程;分析了国外天然气二段转化合成甲醇的主要技术参数;从工艺特征、转化流程、设备组合等方面论述了三一段纯氧转化制甲醇合成气的设计技术、消耗指标、投资及成本。结果表明,按甲醇售价2 500元/t计,投产后约2年即可收回投资。     

Study of Nonsteady-State Continuous Membrane Column for Gas Separation

Abstract

The permeation and transport processes occurring in a continuous membrane column (CMC) are quite complex, and the system will exhibit inverse response behavior in a certain operating regime. To understand the complex interaction of system variables, this work developed a mathematical model for the CMC and solved the model equations. Dynamic responses of a CMC for the separation of N₂-CO₂, CO₂-O₂, and O₂-N₂ gas mixtures with capillary silicone rubber membranes are presented. The effect of the membrane permeabilities on the CMC dynamics is examined. Responses of system variables to various disturbances, together with the start-up transient of the system, are discussed. The knowledge of the unsteady-state behavior of the CMC will enable us to predict the performance of the CMC and to control the CMC in a dynamic environment.     

油田伴生气轻烃回收工艺研究

主要对油田伴生气的轻烃回收工艺进行研究。轻烃回收是油田地面工程中一个重要的步骤。轻烃回收工艺可以有效的降低天然气的露点,防止天然气中的轻烃在输送管道中凝结影响安全输送,并可回收液化石油气和稳定轻油。轻烃回收工艺中增加吸收塔可以获得较高的C3+收率并有利于提高整个流程的冷量的利用效率。在本文所采取的流程和优化后的工艺参数下所得C3+的理论收率为95.95%,干气、液化气和稳定轻油可以达到储存要求。     

碳纤维生产废水DMSO的膜分离浓缩研究

采用某特种膜,对菜碳纤维生产企业排放的含二甲基亚砜废水进行了实验室和现场膜分离浓缩试验研究。结果表明,采用膜分离方法可以实现碳纤维生产企业排放废水的资源回收及废水达标排放或回用,此工艺具有良好的经济效益及社会效益,适于推广应用。