共查询到20条相似文献,搜索用时 15 毫秒
1.
《Gas Separation & Purification》1993,7(4):253-257
Pressure swing adsorption (PSA) processes based on carbon molecular sieves have been known for more than twenty years. The most important industrial PSA process, the nitrogen PSA process, has been developed during the last ten years into a highly efficient technique for producing nitrogen on site. Nitrogen is currently produced by PSA with impurities down to the ppm level and at flow rates up to 1500 N m3 h−1. The on-site supply of nitrogen using the PSA process is an alternative to cryogenic nitrogen. An overview of the theoretical background, of industrial units including purification by deoxo systems and of the economy of the nitrogen PSA system is presented. 相似文献
2.
Dr. Andreas Möller Dr. Joachim Guderian Dr. Jens Möllmer Marcus Lange Dr. Jörg Hofmann Prof. Roger Gläser 《化学,工程师,技术》2013,85(11):1680-1685
In recent years, the adsorptive air separation was established as one of the most important thermal separation processes for the generation of nitrogen and oxygen from air. Both the effects of equilibrium and kinetics can be applied for the separation of nitrogen and oxygen. Nitrogen can be enriched by an equilibrium effect in the adsorbed phase of zeolites, whereas oxygen remains in the gas phase. In contrast to zeolites, oxygen can diffuse much faster into the pores of carbon molecular sieves resulting in a gas phase enriched with nitrogen. In order to exploit this kinetic separation effect in industrial applications, the properties of carbon molecular sieves, e.g., pore aperture, overall pore volume, or release of heat of adsorption are important. Furthermore, research activities are focused on theoretical approaches to describe the kinetic behavior. 相似文献
3.
4.
低浓度煤层气提纯的研究现状 总被引:1,自引:1,他引:0
煤矿开采过程中排放出大量低浓度煤层气,提纯利用这部分煤层气对我国能源开发利用和环境保护意义重大,其难点是经济高效地分离CH4和N2.本文从CH4/N2分离技术、变压吸附分离CH4/N2吸附剂和制备新型炭分子筛3个方面逐层对低浓度煤层气提纯进行了综述和展望.介绍了CH4/N2分离技术研究进展,对其在低浓度煤层气提纯中的应用前景进行了对比.概述了常用变压吸附剂分离CH4/N2的研究现状,分析了它们在低浓度煤层气提纯应用中的优缺点,并提出了制取适合低浓度煤层气提纯用的新型炭分子筛的方法. 相似文献
5.
The separation of air for nitrogen production can be carried out by pressure-swing-adsorption over a carbon molecular sieve. The separation is kinetically controlled, since the equilibrium adsorption of both oxygen and nitrogen is very similar, but the adsorption kinetics for oxygen is faster than for nitrogen. Several methods to prepare carbon molecular sieves are reported. In this work, we synthesized a carbon molecular sieve from a commercial activated carbon. After deposition of polyfurfuryl alcohol, these materials were subjected to carbonization at 800°C under an inert atmosphere. All the microporous materials were characterized by analysis of kinetics and equilibrium adsorption data. The molecular sieve performance was assessed by the O2/N2 uptake ratio. The material prepared by two depositions has characteristics similar to those of commercial CMS. 相似文献
6.
7.
8.
Carbon molecular sieves are adsorbents for gas separation processes of increasing importance. A variety of carbonaceous adsorbents, activated carbons and improved carbon molecular sieves, all with different pore size distributions, can be produced, systematically, by using different steps in the manufacturing process. The two types of carbon molecular sieves, CMSN2 and CMSH2, carefully developed by Bergbau-Forschung GmbH, can be distinguished by different separation mechanisms. The procedure of manufacturing the carbon molecular sieves type CMSN2 and type CMSH2 and their application in an air separating process for nitrogen recovery and hydrogen or nobel gas recovery processes, respectively, using different feed gases, is discussed. 相似文献
9.
《Gas Separation & Purification》1993,7(4):259-263
Experimental results are reported on a pressure swing adsorption (PSA) process using carbon molecular sieve (CMS) for the separation of a gas mixture containing carbon dioxide, hydrocarbons (methane, ethane, propane, etc.) and nitrogen. This PSA process has direct applications in carbon dioxide removal or purification from landfill gas, natural gas processing plants and tertiary oil recovery effluent streams. The CMS-based PSA process separates the carbon dioxide in a single stage by using the differences in component diffusivities. This approach, therefore, provides a significant advantage compared to conventional equilibrium adsorption processes which require one separation stage for removing components such as ethane and propane that are more strongly adsorbed than carbon dioxide and another separation stage for removing components such as methane and nitrogen that are less strongly adsorbed than carbon dioxide. The CMS-based PSA process operates between a feed pressure of 20 to 40 bars and a regeneration pressure of 1.5 bars at ambient temperature and produces a 98+% carbon dioxide product. The PSA process can be integrated with a liquid carbon dioxide plant to produce food grade product. 相似文献
10.
11.
粘结剂对不粘煤制炭分子筛的影响 总被引:1,自引:0,他引:1
研究以不粘煤为原料,以煤焦油、R-树脂以及它们的混合物为粘结剂和调孔剂,制备空分用炭分子筛的工艺方法,考察了粘结剂种类和配比对炭分子筛空分性能的影响。结果表明,R-树脂的引入改进了工艺条件和炭分子筛性能。适宜的R-树脂/煤焦油/不粘煤配比为5/20/100。 相似文献
12.
针对碳分子筛对氮气/甲烷分离体系分离比低的问题,采用浸渍法以市售空分碳分子筛(CMS)为基体,制备了分离氮气/甲烷的铁离子改性碳分子筛。通过静态吸附量、分离比、吸附动力学及热力学性质考察了铁离子负载量对碳分子筛吸附分离氮气/甲烷性能的影响。结果表明:铁(Ⅲ)的负载减小了CMS的比表面积、微孔体积和孔径,使CMS超微孔的孔径分布呈现更集中的趋势。这种集中性以动力学性能下降为代价,明显提高了碳分子筛对氮气/甲烷的吸附分离比。在303 K、0.7 MPa条件下,综合性能优异的0.3%铁改性CMS具有6.03的氮气/甲烷吸附分离比。 相似文献
13.
《Gas Separation & Purification》1990,4(3):141-148
The original pressure swing air separation process, developed almost simultaneously by Exxon and Air Liquide, uses a nitrogen selective zeolite adsorbent to produce a high purity oxygen product. The same basic process is still widely used in small scale units although, for larger scale units, many modifications to the cycle have been introduced in order to reduce power consumption. Although nitrogen can in principle be recovered from the blowdown stream of such systems, if high purity nitrogen is the required product, it is more economic to use an oxygen selective adsorbent. Most adsorbents show either no selectivity or preferential adsorption of nitrogen. However, in small pore carbon molecular sieves or 4A zeolite there is a substantial difference in diffusion rates so that an efficient kinetic separation is possible. Somewhat different cycles are generally used in such processes. Progress in modelling the dynamic behaviour of both types of PSA system is reviewed and comparisons between experimental performance and the model predictions are shown. A simple linear driving force model provides a good overall prediction of the effects of process variables but the computationally more cumbersome diffusion model gives better quantitative agreement with experiment. Comparisons are drawn between the performance achieved (in nitrogen production) with two different kinetically selective adsorbents; RS-10 (a modified 4A zeolite) and Bergbau Forschung carbon molecular sieve. 相似文献
14.
《Gas Separation & Purification》1993,7(4):274-278
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%. 相似文献
15.
J. Sadeghzadeh Ahari S. Pakseresht M. Mahdyarfar S. Shokri Y. Zamani A. Nakhaei pour F. Naderi 《化学工程与技术》2006,29(1):50-58
A general dynamic model is developed for separation of air over a carbon molecular sieve and a zeolite adsorbent for production of nitrogen and oxygen. The proposed model is validated using experimental data from working laboratory scale N2–PSA and laboratory scale O2–PSA systems. Simulations studies are performed to investigate the effect of changing various process variables, such as the duration of PSA steps, bed length and feed inlet velocity. 相似文献
16.
Adsorptive separation of oxygen from nitrogen and argon is carried out during the desorption steps of a pressure swing adsorption (PSA) process which uses carbon molecular sieves developed by Bergbau-Forschung GmbH. The adsorption isotherms of the three main components of air are very similar. On account of the pore size distribution of CMSN2, the diffusion coefficient of oxygen is more than eight times those of nitrogen and argon so that air separation occurs by adsorption kinetics. Experimental results for the individual steps and cyclic operation of the PSA process are presented and compared with the predictions of an isothermal plug-flow model. Adsorption rate is represented by a linear driving force equation. If the diffusion coefficients are adapted separately to every step, a good agreement is observed between the model calculations and experimental results. 相似文献
17.
碳沉积法制富氮用炭分子筛的研究 总被引:1,自引:0,他引:1
本文提出的碳沉积法是用煤焦油馏分油的有机溶液浸渍煤炭化物,然后热解以进行“孔调变”。确定了最佳工艺条件,制得富氮性能良好的炭分子筛。并用D-A方程求取了各种样品的微孔结构参数。 相似文献
18.
19.
Adsorption of carbon dioxide, ethane, and methane on titanosilicate type molecular sieves 总被引:1,自引:0,他引:1
Alejandro Anson Steven M. Kuznicki James A. Sawada 《Chemical engineering science》2009,64(16):3683-3687
The separation of carbon dioxide from light hydrocarbons is a vital step in multiple industrial processes that could be achieved by pressure swing adsorption (PSA), if appropriate adsorbents could be identified. To compare candidate PSA adsorbents, carbon dioxide, methane, and ethane adsorption isotherms were measured for cation exchanged forms of the titanosilicate molecular sieves ETS-10, ETS-4, and RPZ. Mixed cation forms, such as Ba/H-ETS-10, may offer appropriate stability, selectivity, and swing capacity to be utilized as adsorbents in CO2/CH4 PSA processes. Certain cation exchanged forms of ETS-4 were found to partially or completely exclude ethane by size, and equivalent RPZ materials were observed to exclude both methane and ethane, while allowing carbon dioxide to be substantially adsorbed. Adsorbents such as Ca/H-ETS-4 and Ca/H-RPZ are strong candidates for use in PSA separation processes for both CO2/C2H6 and CO2/CH4, potentially replacing current amine scrubber systems. 相似文献
20.
The membranes were prepared by the incorporation of highly hydrophobic silicalite and carbon molecular sieves (CMS) from different precursors into the PDMS casting solutions. The pervaporative removal of VOCs, such as benzene, from aqueous solutions was carried out using the separation factor and permeation flux as the evaluating parameters. The effects of the CMS types and structures, feed concentrations on the pervaporation performance were preliminarily investigated. 相似文献