焦炉煤气变压吸附制氢装置五塔与六塔工艺方案的比较

以氢气产能1 000 m3/h的焦炉煤气变压吸附制氢装置为例,介绍了常用的五塔和六塔流程2种工艺技术方案,分析比较了其工艺配置、运行程序切换方式和建造成本的差异,并说明其各自的适用场合与优劣。     

Application of high‐pressure swing adsorption process for improvement of CO2 recovery system from flue gas

Although the super cold separator applied to the system for CO₂ recovery from flue gas can produce pure CO₂ liquid, the CO₂ recovery efficiency is low. Therefore, the addition of a PSA plant was considered for the secondary CO₂ recovery from the noncon‐densing gas to improve the efficiency. The PSA plant was operated for adsorption at the same pressure as that of the super cold separator and for desorption at the atmospheric pressure. From both the simulation and the experimental data, it was confirmed that CO₂ could be concentrated from 50% in the noncondensing gas to 70% in the recovery gas by the PSA plant and the CO₂ recovery efficiency of the plant was about 90%.     

黄磷尾气变温、变压吸附净化技术的新进展

由于黄磷尾气净化分离难度大,阻碍了黄磷中CO的有效利用。介绍达科特能源科技公司开发的黄磷尾气净化分离新技术。其特点是:1)用焦炭过滤除尘和脱磷泥,再用变温吸附法脱磷、硫和砷的氢化物;2)用湿式氧化法脱硫,回收单质硫;3)用真空变压吸附法脱碳。该新工艺成功应用于合成甲酸钠的工业装置。     

变压吸附氯乙烯精馏尾气工艺改进

介绍了变压吸附氯乙烯精馏尾气的工艺改进情况,改进后的工艺采用分路回收方法,实现了氯乙烯、乙炔和氢气的分别回收,该工艺运行平稳,可降低转化系统负荷,且氯乙烯和乙炔均达到了零排放,具有一定的经济效益和环境效益。     

Comparative simulation study of PSA,VSA, and TSA processes for purification of methane from CO2 via SAPO-34 core-shell adsorbent

Cyclic adsorption processes of PSA, VSA, and TSA were modeled and numerically simulated using SAPO-34 core-shell adsorbent. The results were compared with ordinary SAPO-34 to achieve a more efficient process for CO₂–CH₄ separation. OCM coupled with method of lines was used for numerical solution of the mechanistic model. The simulation results revealed higher efficiency of core-shell adsorbent with less usage of SAPO rather than the ordinary adsorbent to achieve the same degree of purification and recovery. VSA and TSA processes against PSA resulted in CH₄ purification capability more than 99% with more than 73% recovery. However, VSA process has revealed higher productivity rather than TSA.     

Separation of He/N2/CH4 ternary mixtures by a triple-reflux pressure swing adsorption process

Conventional pressure swing adsorption (PSA) processes can only produce one high purity product in a single stage, whereas the state-of-art dual-reflux PSA (DR-PSA) can produce two high purity products simultaneously. However, multicomponent gas separation is often required in the industry, targeting at recovering several valued products at the same time. In this study, we propose a novel adsorption process, namely triple-reflux PSA (TR-PSA), to separate three components simultaneously. A middle product outlet and a middle reflux stream were introduced to the adsorption columns of a conventional DR-PSA process to separate ternary mixtures of nitrogen, methane, and helium. Nonisothermal dynamic models were built to investigate the impacts of operating parameters particularly the location of the middle reflux/product stream and the middle reflux flow rates. Results showed that the TR-PSA process successfully separated ternary mixtures obtaining three enriched products simultaneously in a single stage, yielding a separation performance comparable to that of the double-stage DR-PSA with significantly lower capital and energy cost.     

混合气组分对CO在稀土复合吸附剂上吸附的影响

采用吸附柱动态实验装置,分别考察了混合气组分H2O、CO2、CH4对稀土复合吸附剂变压吸附CO的影响。实验结果表明,原料气中微量的H2O的存在对稀土复合吸附剂的吸附性能有较大影响,当水质量浓度仅为250mg/L时,CO的变压吸附量下降约35％;与CO相比,CO2在稀土复合吸附剂上为弱吸附组分,但对CO的吸附性能有一定影响,当CO2体积分数为1％时,CO的变压吸附量可维持在12.5 ml/g左右;而CH4的存在对CO在稀土复合吸附剂上的吸附量影响不大。     

复合床层变压吸附法脱除合成气中微量CO和CO_2

采用分别装载活性炭和NA型吸附剂的复合床层的变压吸附工艺来脱除合成气中微量的CO和CO2,并利用Aspen-Adsim软件对其进行模拟和优化。模拟结果表明,吹扫气量对工艺性能有较大的影响,吹扫气由处在顺放步骤的吸附塔提供,因此在顺放步骤将床层压力降至较低压力,可获得较大的吹扫气量,此时的工艺性能也较优。模拟结果还表明,均压次数对工艺性能也有影响。在相同的顺放压降下,将变压吸附过程中的3次均压变为2次均压,可减少吸附剂用量,吸附剂产率更高,但塔底尾气量要相应增加。     

Numerical analysis of a dual refluxed PSA process during simultaneous removal and concentration of carbon dioxide dilute gas from air

The simultaneous removal and concentration of carbon dioxide present in ambient air were carried out by a dual refluxed Pressure Swing Adsorption (PSA) process with intermediate feed inlet position. The feed inlet position divides each column into rectifying and stripping sections from which enriched and lean gases can be simultaneously produced. A simple isothermal model with negligible axial dispersion and pressure drops through the PSA beds was developed to investigate the effects of various combinations of the operating variables and to analyze semi-quantitatively the effects of the main characteristic parameters such as the dimensionless feed inlet position (Z_R/L_T) and the stripping-reflux ratio (R_r). A good agreement between the model prediction and the experimental results was obtained. Moreover, an optimum feed inlet position was found and it corresponded to a position where the carbon dioxide mole ratio in the feed flux and that in the upstream flux leaving the stripping section were equal. The carbon dioxide mole ratio in the enriched product (Y_E) as well as that in the lean product (Y_L) were strongly dependent on the ratio of feed/enriched product flow rates (Q_F/Q_E) and the ratio of feed/lean product flow rates (Q_F/Q_L). Although the pressure ratio (P_a/P_d) was crucially important for the separation performance, a smaller value of R_r was sufficient to reach a performance which is unattainable in conventional PSA processes.     

Hybrid FSC membrane for CO2 removal from natural gas: Experimental,process simulation,and economic feasibility analysis

The novel fixed‐site‐carrier (FSC) membranes were prepared by coating carbon nanotubes reinforced polyvinylamine/polyvinyl alcohol selective layer on top of ultrafiltration polysulfone support. Small pilot‐scale modules with membrane area of 110–330 cm² were tested with high pressure permeation rig. The prepared hybrid FSC membranes show high CO₂ permeance of 0.084–0.218 m³ (STP)/(m² h bar) with CO₂/CH₄ selectivity of 17.9–34.7 at different feed pressures up to 40 bar for a 10% CO₂ feed gas. Operating parameters of feed pressure, flow rate, and CO₂ concentration were found to significantly influence membrane performance. HYSYS simulation integrated with ChemBrane and cost estimation was conducted to evaluate techno‐economic feasibility of a membrane process for natural gas (NG) sweetening. Simulation results indicated that the developed FSC membranes could be a promising candidate for CO₂ removal from low CO₂ concentration (10%) NGs with a low NG sweetening cost of 5.73E?3 $/Nm³ sweet NG produced. © 2014 American Institute of Chemical Engineers AIChE J 60: 4174–4184, 2014     

Integrated adsorption and absorption process for post-combustion CO2 capture

This study explored the feasibility of integrating an adsorption and solvent scrubbing process for post-combustion CO₂ capture from a coal-fired power plant. This integrated process has two stages: the first is a vacuum swing adsorption (VSA) process using activated carbon as the adsorbent, and the second stage is a solvent scrubber/stripper system using monoethanolamine (30 wt-%) as the solvent. The results showed that the adsorption process could enrich CO₂ in the flue gas from 12 to 50 mol-% with a CO₂ recovery of >90%, and the concentrated CO₂ stream fed to the solvent scrubber had a significantly lower volumetric flowrate. The increased CO₂ concentration and reduced feed flow to the absorption section resulted in significant reduction in the diameter of the solvent absorber, bringing the size of the absorber from uneconomically large to readily achievable domain. In addition, the VSA process could also remove most of the oxygen initially existed in the feed gas, alleviating the downstream corrosion and degradation problems in the absorption section. The findings in this work will reduce the technical risks associated with the state-of-the art solvent absorption technology for CO₂ capture and thus accelerate the deployment of such technologies to reduce carbon emissions.     

氯乙烯精馏尾气中氢气分离提纯系统运行总结

简要介绍了氯乙烯精馏尾气中氢气吸附分离的原理,详细介绍了氢气分离提纯装置的工艺流程及其在实际操作中的注意事项。     

丙烷脱氢反应气分离提纯丙烯和氢气过程严格模拟与能效评估

丙烷脱氢(PDH)是生产丙烯产品的重要方式之一,丙烷脱氢反应气组分复杂,为获得聚合级丙烯和纯度不小于99.90 mol/mol的氢气产品,在Aspen软件中对丙烷脱氢反应气分离和富氢尾气回收氢气的过程进行建模和模拟,分离过程包括醇胺脱碳、压缩深冷、脱乙烷、丙烯精馏和变压吸附单元。为了合理利用丙烯精馏塔的能量,对丙烯精馏塔进行能量集成,采用变压吸附工艺回收氢气并对分离过程工艺参数进行灵敏度分析及优化工艺参数,以提高经济性和能效。模拟结果可得到符合要求的丙烯和氢气产品,单位产品能耗分别为267.46 kg标准油/t丙烯产品,474.44 kg标准油/t氢气产品。     

双塔微型变压吸附制氧机实验和模拟

设计一种两吸附床小型PSA制氧机，并在低压舱内模拟海拔高度对两吸附床小型PSA制氧机的影响，同时对结构参数以及操作参数的影响进行考察，建立制氧工艺流程数学模型，通过实验对比，微调模型使之与实际相符，验证模型的准确性，并开展数值仿真与模拟研究，以确定相关的内在参数及外部因素对制氧过程及制氧效果等性能指标的影响规律，得到不同海拔不同工况下，较优的设计参数和操作参数，从而提高制氧效率，降低制氧机的制造和运行成本。     

Simple control structure for a compression purification process in an oxy‐combustion power plant

The composition of the stack gas from an oxy‐combustion power plant is about 75 mol % carbon dioxide. The stream must be purified to about 95 mol % by removing light inerts such as nitrogen, oxygen, and argon. The product stream must be compressed to 110 bar for sequestration. This article presents a simple control structure for the double‐flash compression and purification process to achieve these objectives. © 2015 American Institute of Chemical Engineers AIChE J, 61: 1581–1588, 2015     

三种气体分离技术应用于电厂烟气二氧化碳捕集经济性的比较(英文)

Three gas separation technologies,chemical absorption,membrane separation and pressure swing adsorption,are usually applied for CO2 capture from flue gas in coal-fired power plants.In this work,the costs of the three technologies are analyzed and compared.The cost for chemical absorption is mainly from $30 to $60 per ton(based on CO2 avoided),while the minimum value is $10 per ton(based on CO2 avoided).As for membrane separation and pressure swing adsorption,the costs are $50 to $78 and $40 to $63 per ton(based on CO2 avoided),respectively.Measures are proposed to reduce the cost of the three technologies.For CO2 capture and storage process,the CO2 recovery and purity should be greater than 90%.Based on the cost,recovery,and purity,it seems that chemical absorption is currently the most cost-effective technology for CO2 capture from flue gas from power plants.However,membrane gas separation is the most promising alternative approach in the future,provided that membrane performance is further improved.     

Approximation of a PSA process based on an equivalent continuous countercurrent flow process: Blow-up and blow-down representation

To design cyclic separation processes by adsorption, such as pressure swing adsorption (PSA) processes, one has to simulate the start-up time in order to determine the cyclic steady state (CSS), which can be very time-consuming. A fast way to estimate the CSS reached by a PSA process is proposed by Suzuki (1985)—assuming equivalency between the PSA system and a continuous countercurrent flow system (CCF). The CCF model is improved in the present paper, taking into account the gaseous phase located in a column when the system switches from a constant pressure step to another step. By performing a parametric study, the limits of the CCF model are tested. It is shown that this model can quantitatively predict the purities and recoveries obtained at CSS for kinetically controlled separation by comparison with a detailed model of PSA. It is also shown that the CCF model can also give a good approximation of the dynamic behavior of the PSA process. Finally, the simulation of dry air separation is proposed.     

低温甲醇脱碳工艺热力学模型和过程模拟研究

为了进行含高压气体和强极性物质的体系的低温甲醇脱碳工艺的模拟研究,建立相应的热力学模型.采用Soave-Redlich-Kwong(SRK)立方型状态方程,结合Huron-Vidal混合规则和非随机双流体Non-Random-Two-Liquid(NRTL)活度系数模型建立的热力学模型,从气体溶解度和气液平衡数据拟合获...     

变压变温吸附法回收精馏尾气中氯乙烯新工艺

介绍了变压变温吸附回收氯乙烯精馏尾气的新工艺,与传统的回收工艺相比,新工艺具有DCS控制自动化程度高,运行稳定,操作方便,安全性能好等优点。实际运行结果表明该工艺氯乙烯的回收率达99.99%以上,放空尾气中氯乙烯体积分数低于65×10-6,回收的产品中氯乙烯体积分数达90%以上,符合设计要求。     

Analysis of energetics and economics of sub-ambient hybrid post-combustion carbon dioxide capture

Adsorption of CO₂ from post-combustion flue gas is one of the leading candidates for globally impactful carbon capture systems. This work focused on understanding the opportunities and limitations of sub-ambient CO₂ capture processes utilizing a multistage separation process. A hybrid process design using a combination of pressure-driven separation of CO₂ from flue gas (e.g., adsorption- or membrane-based separation) followed by CO₂-rich product liquefaction to produce high-purity (>99%) CO₂ at pipeline conditions is considered. The operating pressure of the separation unit is a key cost parameter and also an important process variable that regulates the available heat removal necessary to reach the sub-ambient operating conditions. The economic viability of applying pressure swing adsorption (PSA) processes using fiber sorbent contactors with internal heat management was found to be most influenced by the productivity of the adsorption system, with productivities as high as 0.015 /kg_sorb⁻¹ sec⁻¹ being required to reduce costs of capture below $60/ton CO₂ captured. This analysis was carried out using a simplified two-bed process, and thus there is opportunity for further cost reduction with exploration of more complex cycle designs. Three exemplar fiber sorbents (MIL-101(Cr), UiO-66, and zeolite 13X) were considered for application in the sub-ambient process of PSA unit. Among the considered sorbents, zeolite 13X fiber composites were found to perform better at ambient temperatures as compared to sub-ambient. MIL-101(Cr) and UiO-66 fiber composites had improved purity, recovery, and productivity at colder temperatures reducing costs of capture as low as $61/ton CO₂. Future economic improvement could be achieved by reducing the required operating pressure of the PSA unit and pushing the Pareto frontier closer to the final pipeline requirement via a combination of PSA cycle design and material selection.