变压吸附制氧吸附剂的发展状况

介绍了变压吸附制氧的原理方法及流程特点,回顾了变压吸附制氧吸附剂的发展状况并重点介绍了LiX分子筛,进一步指出了制氧吸附剂的选择原则,提出了未来制氧吸附剂的研究方向,最后并对变压吸附制氧的发展做了展望。     

会议消息

<正> 变压吸附法分子筛制富氧中试技术鉴定会在临潼开召陕西省石油化学工业局受化工部科技局委托,于一九七九年十二月十六日至十八日在陕西省临潼县主持召开了变压吸附法分子筛制富氧中试技术鉴定会。参加会议的有陕西省科委及有关科研、设计和分子筛生产厂等22个单位,共38名代表。会议听取了化工部化肥研究所关于变压吸附法分子筛制富氧的中试技术总结报告。接着分组进行了认真细致的讨论,一致认为:变压吸附法分子筛制富氧的试验结果证明,采用固定床三塔一次均压流程制取中等     

会议消息

<正> 变压吸附法分子筛制富氧中试技术鉴定会在临潼开召陕西省石油化学工业局受化工部科技局委托,于一九七九年十二月十六日至十八日在陕西省临潼县主持召开了变压吸附法分子筛制富氧中试技术鉴定会。参加会议的有陕西省科委及有关科研、设计和分子筛生产厂等22个单位,共38名代表。会议听取了化工部化肥研究所关于变压吸附法分子筛制富氧的中试技术总结报告。接着分组进行了认真细致的讨论,一致认为:变压吸附法分子筛制富氧的试验结果证明,采用固定床三塔一次均压流程制取中等     

分子筛氮氧分离性能的测定方法

分子筛以其对氮氧具有选择性吸附的特性而成为变压吸附空分制氧领域应用的主体吸附剂。分子筛氮氧分离性能的测定方法对变压吸附用分子筛产品的质量控制具有重要的理论和现实意义。简述了目前常规的分子筛氮氧分离性能测定方法,并介绍了相关测定原理、测定过程,分析了测定过程的优缺点。经比较,容量法更适合作为氮氧分离性能评价的标准方法来进行推广。     

浅论变压吸附制氧的经济性

70年代迅速发展起来的变压吸附制氧技术(PSA)受到各国的关注和重视。国外已进入工业应用阶段。近年来,日本、联邦德国等对分子筛的研制获突破性进展,使变压吸附制氧工艺从二塔式向三塔式、四塔式发展。     

我国变压吸附制氧吸附剂及工艺研究进展

新型吸附剂和变压吸附工艺开发是提高变压吸附装置性能的主要途径。本文综述了我国变压吸附制氧吸附剂改性及变压吸附制氧工艺研究进展,并指出目前存在问题:LiLSX型及Li⁺和其他离子的混合型吸附剂具有良好氧氮分离性能,但仍存在离子交换利用率低、成本高等问题;其他离子改性的吸附剂制备过程相对简单,但也有分离系数低或成本高等缺点;基于循环步骤改进的变压吸附制氧工艺优化研究大多以实验室规模制氧装置为主,未深入研究优化工艺的过程性能,难以有效地指导工业级制氧装置工艺优化;快速和双回流变压吸附制氧新工艺具有广阔发展前景,但相关研究欠深入;而多级和耦合变压吸附制氧工艺具有广阔应用前景,但存在流程复杂、能耗较高等缺点。指出未来制氧吸附剂和制氧工艺研究应进一步研究固相离子交换方法,提高LSX吸附剂Li⁺交换利用率,降低成本;开展优化工艺的过程性能研究,指导工业级制氧装置优化;加强快速变压吸附和双回流变压吸附制氧工艺研究,推动工程化应用。     

读者信箱

<正> 一、问:什么叫变压吸附?答:变压吸附是利用分子筛在不同的压力及温度条件下,对混合气体进行选择性的吸收,并控制压力及温度进行解吸,用以达到分离混合气体的目的。如石油化工、化肥工业以及其它行业中均有应用。如利用分子筛变压吸附分离合成氨厂驰放气中的甲烷及氢;利用分子筛变压吸附分离空气中的氧及氮,利用分子筛变压吸附分离空气中的二氧化碳。这些分子筛有沸石,碳以及 A 型分子筛等。二、问:碳酸氢铵肥料堆放在露天有什么害     

制纯氧分子筛

变压吸附(Press Swing Adsorption,PSA)制纯氧具有很好的工业应用前景,但氩气和氧气在制氧分子筛上的吸附选择性接近于1,因而不能分离,不能通过一步PSA制备出纯度高于95%的氧气。氩气和氧气在银离子交换沸石分子筛上的吸附选择性大于1,有可能成为制纯氧分子筛,但目前其选择性还不能满足工业分离的要求。本文介绍了银离子交换沸石分子筛在制纯氧领域的研究进展,并探讨了制纯氧分子筛的研究展望。     

变压吸附制氮技术的发展和应用

综述了变压吸附技术的原理、发展及碳分子筛和沸石分子筛两种吸附剂变压吸附技术制氮的国内外研究进展,提出了变压吸附技术制氮的发展方向。     

分子筛变压吸附法制富氧取得较好结果

吉林省石油化工设计研究院为了配合化肥和冶金工业迅速发展的需要,于1975年开展了分子筛吸附制取富氧的研究。经三结合试验小组的努力,仅用几个月的时间,就胜利地完成了每小时产氧20立升的小试验任务,并且建成了3～4米~3/小时制氧能力的扩大试验装置,并进行了试运转。变压吸附法制富氧,是七十年代世界上才开始得到工业化应用的一项制氧新技术。变压吸附法制富氧大致可分为三大类:一是加压吸附常压解吸;二是常压吸附真空解吸;三是加压吸附真空解吸。其中加压吸附常压解     

Synthesis and ion exchange of zeolites produced from kaolin for separation of oxygen from atmospheric air

Lithium-based zeolites are the most commonly used materials in PSA (pressure swing adsorption) oxygen concentration from atmospheric air. Synthesizing these adsorbents using mineral raw materials adapts to worldwide environmental requests, as only high-purity chemical reactants such as aluminates and silicates are usually used. The present work aims to synthesize and characterize zeolites using kaolin as raw material by studying the influence of the metakaolinization temperature and SiO₂/Al₂O₃ and H₂O/Na₂O molar ratios by experimental design. Ion exchange was used to incorporate lithium into synthesized zeolites. Kaolin was treated thermically and characterized, and zeolites were synthesized by a hydrothermal reaction. After synthesis, ionic exchange of Na⁺ ions by Li⁺ was performed. The results indicated the presence of three main phases, zeolites A, X, and P. Using ANOVA, it was found that the factors that contributed significantly to the formation of zeolite X were the H₂O/Na₂O and SiO₂/Al₂O₃ molar ratios. For zeolite A, the major influence was by the metakaolinization temperature and for zeolite P none of the factors was influential. Zeolites that incorporated higher amounts of lithium showed higher N₂ adsorption potential, indicating that even without pure phases formed, it was possible to obtain similar adsorption efficiency to commercial zeolite.     

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。     

Stable oxygen-selective sorbents for air separation

Commercial sorption-based air separation is usually done using nitrogen selective zeolites in pressure swing adsorption (PSA) systems. Separation of air by adsorption of less abundant oxygen is more desirable. In this study we have developed some stable oxygen selective sorbents with silver and cerium salts. AgCl, AgBr, AgI and CeCl₃ all showed stable adsorption characteristics with pure component selectivity of O₂/N₂∼2.0-3.0 at 1 atm. For these salts heat of adsorption of oxygen was found to be slightly higher than that of nitrogen, which was also predicted by ab initio molecular orbital calculations by Chen and Yang (Ind. Eng. Chem. Res. 35 (1996) 4020). The adsorption capacity of these salts was increased by thermal dispersion on high surface area SiO₂ support. AgBr thermally spread on SiO₂ is the best sorbent obtained in this study. AgBr/SiO₂ (1.0 g/g) showed a pure component oxygen selectivity of ∼3 at 1 atm and ∼5 at 7 atm. PSA simulations were used to show the feasibility of nitrogen production using AgBr/SiO₂.     

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%.     

变压吸附制氢过程吸附剂性能

研究了Ｈ２ＣＯ２ＣＨ４ＣＯ混合气在活性炭（ＡＣ）和分子筛（ＭＳ）上的变压吸附（ＰＳＡ）过程，各组分在ＡＣ上的吸附能力为：ＣＯ２的大于ＣＨ４的，ＣＨ４的大于ＣＯ的；在ＭＳ上为：ＣＯ的大于ＣＨ４的。并研究了混合气在ＡＣＭＳ复合床层上的ＰＳＡ过程，其中ＡＣ充填于进口端，主要吸附ＣＯ２和ＣＨ４；ＭＳ主要吸附ＣＯ，为复合床层ＰＳＡ过程的模拟计算和设计提供了基础。     

Oxygen Production by Pressure Swing Adsorption

Abstract

The specific oxygen production capacity and the oxygen recovery of a pressure swing adsorption (PSA) process for the production of oxygen from ambient air by selective adsorption of nitrogen can be increased by operating the process at a superambient temperature. The higher temperature operation provides more efficient desorption of nitrogen from the adsorbent which more than off-sets the detrimental effects of the lower selectivity and capacity of adsorption of nitrogen from air at the elevated temperature. The concept is demonstrated by evaluating the performance of an eight-step PSA-oxygen process to produce a 90% oxygen product stream at different temperatures. It is shown that 10% higher oxygen production capacity and 14.5% larger oxygen recovery can be obtained by operating the PSA process at 60°C compared to its performance at 30°C. The PSA process and its performance data from a pilot plant are discussed.     

Production of pure ethanol from azeotropic solution by pressure swing adsorption

Pressure swing adsorption (PSA) is attractive for final separation in the process of water removal especially for fuel ethanol production. Despite many researches on simulation and experimental works on adsorption of water on 3A zeolite in a fixed bed, none have studied a process with the actual PSA system. The purpose of this research was to study the PSA process with two adsorbers and effects of several parameters. The research also included analysis of kinetic and thermodynamic data of ethanol-water adsorption on commercial 3A zeolites in a single fixed bed. A two-level factorial design experiment was used in this research work to preliminarily screen the influence and interaction among the factors. Effects of important parameters such as initial temperature, feed concentration and feed rate were investigated. It was proven that the Langmuir isotherm could best predict the experimental results. In the PSA pilot test, the principal factors, which had effects on the performance, were feed rate, feed concentration, adsorption pressure and the cycle time. Prediction of the process efficiency in terms of ethanol recovery and enrichment was proposed in the form of regression models. The results of the study in a fixed bed adsorber could help designing a pilot-scale PSA unit. The experiments proved to be successful in terms of producing high concentration ethanol with high percentage of ethanol recovery. With further simulation work the process could be scaled up for an industrial use.     

Performance of iron-incorporated A-type zeolites for O2/N2 separation from air by pressure swing adsorption

The performance of various metal ion-exchanged A-type zeolites and metal-incorporated A-type zeolites for O₂ and N₂ adsorption was studied to provide a pressure swing adsorption (PSA) process. Metal-incorporated A-type zeolites adsorbed N₂ in larger quantities than metal ion-exchanged A-type zeolites. Compared with Na-A zeolite, both Cu-incorporated and Ni-incorporated A-type zeolites adsorbed larger quantities of N₂. The incorporation of Cu or Ni enlarged the pore size of the zeolite, while Fe incorporation reduced it. However, the adsorption volume ratio of O₂ to N₂ could be increased to as high as 4.2 on Fe-incorporated A-type zeolite calcined at 750°C, which was the highest value among the samples tested. The amount of adsorption of O₂ was 38.0 ml g⁻¹, which was comparable with ordinary Na-A zeolite. The Fe incorporation markedly improved the performance of ordinary Na-A zeolite in O₂/N₂ separation. Therefore, Fe-incorporated A-type zeolite has a high potential as a good adsorbent for pressure swing adsorption in O₂/N₂ separation from air.     

Separation of Gases by Pressure Swin

Abstract

The recent status of pressure swing adsorption (PSA) as a process for separating multicomponent gas mixtures is reviewed. The applications of a new generation of adsorbents, such as zeolites, carbon molecular sieves, and, more recently, pore engineered molecular sieves, are described in detail. The more important theories of adsorption from gas mixtures as well as those of the PSA process are described briefly. The commercial applications of PSA the process-present and potential-are discussed at length.