变压吸附空分制氧的技术进展

介绍了近年来变压吸附空分制氧的技术进展情况,分别从空分制氧的工艺和吸附剂的改进状况进行了详细论述,并简单的描述了空分制氧的发展前景。     

13X-APG沸石真空变压变温耦合工艺吸附捕集烟道气中CO2

采用13X-APG沸石吸附捕集烟道气中CO2,并研发了五步循环真空变压变温(VTSA)耦合吸附捕集工艺. 实验测定了循环吸附/解吸过程中吸附剂再生率、烟道气中CO2回收率、产品气量及产品气中CO2纯度,并与传统的真空变压吸附工艺(VSA)和变温吸附工艺(TSA)比较. 由于VTSA在真空解吸的同时加热吸附剂,减少了真空泵的电耗,可在较温和的真空下(约3′103 Pa)操作,附加的吸附剂再生温度也不高,90~150℃下吸附剂再生率达97%以上,CO2回收率达98%以上. 吸附剂捕集CO2的量可提高到1.8 mol/kg,是VSA工艺产品气量的2倍,且产品气中CO2纯度提高到90%以上.     

变压吸附制氮机组运行总结

变压吸附空分制氮技术以洁净的压缩空气为原料,利用焦炭分子筛吸附其中的氧气成分,从而制得高纯度的氮气。介绍了变压吸附制氮机组的工作原理、影响氮气纯度的因素以及运行状况。     

变压吸附技术在气体分离提纯中的应用

介绍了变压吸附技术的基本原理、发展概况及基本工作过程,并阐述了该技术在氢气的分离与提纯、二氧化碳的分离与提纯、一氧化碳的分离、空气分离制氧、空气分离制氮、碳的脱除等工业过程中的应用,对变压吸附技术今后的发展提出了展望。     

Performance Comparison of Different Separation Systems for H2 Recovery from Catalytic Reforming Unit Off‐Gas Streams

The performance of pressure swing adsorption (PSA), membrane separation, and gas absorption systems for H₂ recovery from refinery off‐gas stream was studied by simulation‐based data. The PSA process was simulated using adsorbents of silica gel and activated carbon for removing heavy and light hydrocarbons. The mole fraction profiles of all components and the relationship between hydrogen purity and recovery as a function of feed pressure were examined. The solution‐diffusion model was applied for modeling and simulation of a one‐stage membrane process. The gas absorption process with a tower tray was simulated at sub‐zero temperature and the correlation between hydrogen purity and recovery as a function of tower pressure and temperature was evaluated at different solvent flow rates.     

Adsorption of H2, CO2, CH4, CO,N2 and H2O in Activated Carbon and Zeolite for Hydrogen Production

Abstract

The design of a layered pressure swing adsorption unit to treat a specified off-gas stream is based on the properties of the adsorbent materials. In this work we provide adsorption equilibrium and kinetics of the pure gases in a SMR off-gas: H₂O, CO₂, CH₄, CO, N₂, and H₂ on two different adsorbents: activated carbon and zeolite. Data were measured gravimetrically at 303–343 K and 0–7 bar. Water adsorption was only measured in the activated carbon at 303 K and kinetics was evaluated by measuring a breakthrough curve with high relative humidity.     

Carbon-based oxygen selective desiccants for use in nitrogen PSA

Techniques for the production of composite oxygen selective adsorbents are disclosed. These adsorbents are comprised of a carbon molecular sieve (CMS) which is kinetically selective for the adsorption of oxygen over nitrogen and an agent for the sorption of water such as LiCl or SiO₂. The adsorption properties of the composite adsorbents and results obtained from pressure swing adsorption (PSA) process testing are presented. The composite adsorbents improve the nitrogen PSA process performance (recovery and productivity) over the use of conventional desiccants which do not exhibit oxygen selectivity. Using a standard nitrogen PSA process cycle, replacement of conventional inorganic desiccants like alumina with the current CMS-based desiccants improved air recovery 2 to 4 percentage points and increased nitrogen productivity 15 to 20% at 70°F and a nitrogen purity of 99.5%.     

Equilibrium Analysis of Cyclic Adsorption Processes: CO2 Working Capacities with NaY

Abstract

The most common application of adsorption is via pressure swing adsorption. In this type of design, the feed and regeneration temperatures are kept approximately equal, whereas the feed pressure is higher than the regeneration pressure. By exploiting the difference in the amount adsorbed at a higher pressure to the amount adsorbed at a lower pressure, a working capacity is realized. Therefore, by examining the expected (ideal) working capacity of an adsorbent, a performance characteristic can be analyzed for a pressure swing adsorption process (PSA). For this work, feed pressures up to 2.0 atm CO₂ and feed temperatures from 20°C to 200°C were investigated. These limits were chosen due to the nature of the target process: CO₂ removal from flue gas.

Carbon dioxide adsorption isotherms were determined in a constant volume system at 23°C, 45°C, 65°C, 104°C, 146°C, and 198°C, for pressures between 0.001 and 2.5 atm CO₂ with NaY zeolite. These data were fit with the temperature dependent form of the Toth isotherm. Henry's Law constants and the heat of adsorption at the limit of zero coverage were also determined using the concentration pulse method. Comparison of the Henry's Law constants derived from the Toth isotherm, and those obtained with the concentration pulse method provided excellent agreement.

By using the Toth isotherm, expected working capacity contour plots were constructed for PSA (Pressure Swing Adsorption), TSA (Temperature Swing Adsorption), and PTSA (Pressure Temperature Swing Adsorption) cycles. The largest expected working capacities were obtained when the bed was operated under a high‐pressure gradient PSA cycle, or a high thermal and pressure gradient PTSA cycle. The results also showed that certain TSA and PSA cycle conditions would result with higher expected working capacities as the feed temperature increases.     

气源温度与解吸过程对变压吸附制氧效果的影响

研究了气源温度和解吸条件对制氧效果的影响,结果表明：细长解吸管路会导致吸附塔内氧浓度波前沿在吸附周期内极易穿透床层,在产氧期及间歇期都会有低浓度氧流入储氧罐,造成氧浓度和流量下降;较高的气源温度有利于分子筛解吸再生,在15～65 ℃内,平均每升高10 ℃,产氧体积分数可以提高1.2%。     

氯乙烯变温吸附装置的研究

介绍了采用变温吸附技术对氯乙烯进行干燥脱水的工艺流程及运行效果,阐述了变温吸附装置运行过程中出现的问题及相应的解决方法。     

氯乙烯单体脱水工艺的比较

分别介绍了固碱干燥工艺及变温吸附工艺脱除氯乙烯单体中水分的机制和工艺流程,并比较了2种工艺的应用效果。结果表明:变温吸附工艺的脱水效果优于固碱干燥工艺,且生产连续性更好,吸附剂使用周期长,但对原料气的压力和各工序的温度要求较严格。     

吸附制冷用复合吸附剂的吸附性能

固体吸附式制冷因具有环保和节能两大优势,成为国内外竞相开发的热点,尤其是将其用于新型空调系统和太阳能应用产品方面的开发研究备受关注．但从实用化研究成果来看,还远不满足工业化条件,其主要原因之一是受吸附制冷工质对（吸附剂-制冷剂）的性能制约．目前,国内外关于吸附制冷工质对的研究报道比较多,所采用的吸附（工）质仍然以水、甲醇、乙醇和氨为主,对于吸附剂的研究进展比较快,已从当初单一组分吸附剂的选用发展到目前多组分、复合吸附剂的研制．研制性能优良的吸附剂被认为是推动固体吸附式制冷工业化的关键之一．     

吸附分离CH4/N2可行性研究

The separation between methane and nitrogen is an inevitable and important task in the C1 chemical technology and the utilization of methane from coalbed, yet it is considered to be one of the tough tasks in the field of separation. Pressure swing adsorption is a preferable technology if an adsorbent that allowing a large coefficient of separation for the CH4/N2 system is available. The separation coefficients between CH4 and N2 were obtained on analyzing the breakthrough curves measured experimentally with nine adsorbents. A technique of measuring the temperature-pulse was incorporated in the experiments, and the reliability of the result was improved. Superactivated carbon with large surface area and plenty of micropores was shown to have the largest separation coefficient and to be promising for the commercial utilization.     

沼气变压吸附剂吸附性能比较

研究了工程上常用的3种吸附剂CO2吸附剂硅胶、13X分子筛和碳分子筛在高压(0.1~1 MPa)下对CO2和CH4的吸附容量、稳定性和选择性,以确定其在沼气变压吸附分离中应用的可行性. 结果表明,硅胶的吸附稳定性非常好,0.1 MPa时吸附选择性系数为8~10,能有效分离CH4?CO2;13X分子筛对CH4和CO2吸附容量最高、吸附选择性最好,重复使用5次CO2的吸附容量略有下降;以CH4的损失率作为评价标准时,13X分子筛吸附CH4的损失率最低. 降压不能使被碳分子筛吸附的CH4完全解吸,吸附位不能充分释放,不适用于CH4与CO2的分离.     

IDA工艺路线草甘膦生产废气中H2的回收提纯与利用

IDA工艺路线草甘膦的脱氢岗位产生的H_2尾气中含有较多的杂质,采用水洗、酸洗、除氧、干燥、变压吸附(简称PSA)等工艺进行H_2提纯,H_2含量达99.8%以上,该工艺具有H_2回收率高、品质好,而且能将尾气中的有害杂质除尽等优点。     

磷酸浸渍法制备生物质活性炭吸附氨气

本文研究了磷酸浸渍棕榈壳制备的活性炭用于吸附NH_3。考察了活化温度、H_3PO_4浓度和浸渍时间对活性炭比表面积的影响。本活性炭的氨吸附量不仅仅取决于吸附剂的比表面积,不同于蒸汽法制备的活性炭。在宽温环境下的吸附和解吸实验证明同时发生了物理吸附和化学吸附。化学吸附所导致的氨吸附量与吸附剂表面的氧含量密切相关,化学吸附是由于氨和活性炭表面的一些含氧官能团通过氢键作用而产生的。在此基础上,探讨了磷酸浸渍和化学吸附过程的机理。     

气体分离用变压吸附剂的研究进展

介绍了在应用变压吸附生产N2、O2和CO2的生产过程中,沸石分子筛和碳分子筛的吸附分离机理及它们的改性研究,并讨论了国内外目前使用的沸石分子筛和碳分子筛的优缺点,评述了现阶段国内外变压吸附剂的研究现状,进而展望了变压吸附剂的研究和发展趋势。     

氧化铁改性活性炭的制备及其吸附脱硫性能

制备了负载型氧化铁改性活性炭吸附剂,并采用比表面积（BET）、扫描电镜（SEM）技术对吸附剂进行了表征。在固定吸附床上考察了制备条件及吸附条件对吸附剂脱除硫化氢性能的影响。研究结果表明,负载氧化铁后吸附剂的比表面积由580.4 m2/g提高到658.6 m2/g,氧化铁改性能有效改善活性炭对硫化氢的吸附脱除能力。氧化铁与活性炭的质量比为1∶1,真空干燥温度为70 ℃,干燥时间为36 h时得到的负载氧化铁吸附剂的吸附效果最好。在吸附温度为60 ℃时,饱和硫容和脱硫率分别达到77.4 mg/g和99.2%。饱和硫容比未经改性的活性炭的提高了60.2 mg/g。     

在惰性气体环境中热泵干燥食品

在传统的食品干燥技术中,干燥介质是空气,干燥能力由变化的温度控制。通常,干燥过程在高温下进行,空气中氧的存在影响食品的营养物质。想要在低温条件下提高干燥能力,可以通过热泵来改善干燥环境。热泵是闭环系统,冷凝器产生的热控制干燥温度,蒸发器除去干燥室的水分,干燥介质在低温低湿下运行。由于整个系统在闭路下操作,为了去除空气中氧对食品的影响,采用氮气、二氧化碳等惰性气体代替空气作为干燥介质。本文主要研究：采用氮气、二氧化碳和空气干燥一些热敏性水果,如番石榴和木瓜,探讨对食品营养物质和颜色的影响,并与冷冻干燥、真空干燥的结果进行对比。     

煤层气在活性炭和炭分子筛上变压吸附分离

变压吸附分离是有效的气体分离提纯方法,采用合适的吸附剂可对煤层气(CH4/N2混合气体)进行高效分离,节约能耗。在单床吸附装置上测量了CH4/N2混合气体在3种活性炭和4种炭分子筛吸附柱上的穿透曲线,并进行实验研究再生条件对吸附剂分离性能的影响。实验结果表明,7种吸附剂均对CH4/N2混合气具有一定程度的分离能力,且高温真空再生后吸附效果更好;但仍需开发出更有效的吸附剂。