Integrated vacuum pressure swing adsorption and Rectisol process for CO_(2) capture from underground coal gasification syngas

An integrated vacuum pressure swing adsorption(VPSA) and Rectisol process is proposed for CO_(2) capture from underground coal gasification(UCG) syngas. A ten-bed VPSA process with silica gel adsorbent is firstly designed to pre-separate and capture 74.57% CO_(2) with a CO_(2) purity of 98.35% from UCG syngas(CH_(4)/CO/CO_(2)/H_(2)/N_(2)= 30.77%/6.15%/44.10%/18.46%/0.52%, mole fraction, from Shaar Lake Mine Field,Xinjiang Province, China) with a feed pressure of 3.5 MPa. Subsequently, the Rectisol process is constructed to furtherly remove and capture the residual CO_(2)remained in light product gas from the VPSA process using cryogenic methanol(233.15 K, 100%(mass)) as absorbent. A final purified gas with CO_(2) concentration lower than 3% and a regenerated CO_(2) product with CO_(2) purity higher than 95% were achieved by using the Rectisol process. Comparisons indicate that the energy consumption is deceased from 2.143 MJ·kg^(-1) of the single Rectisol process to 1.008 MJ·kg^(-1) of the integrated VPSA & Rectisol process, which demonstrated that the deployed VPSA was an energy conservation process for CO_(2) capture from UCG syngas. Additionally, the high-value gas(e.g., CH_(4)) loss can be decreased and the effects of key operating parameters on the process performances were detailed.

Pilot-scale Experiment for Purification of CO from Industrial Tail Gases by Pressure Swing Adsorption

Using pressure swing adsorption （PSA） technology to purify carbon monoxide （CO） discharged from industrial gases is a high-efficiency and economical method. In this article, a four-bed PSA experiment for CO purification was improved and optimized, in which a set of 120 m^3·h^-1 pilot-scale PSA device was developed to purify CO from industrial tail gases, a set of control systems suitable for industry production was developed, and the influences of the operating parameters on CO purification were investigated. The experimental results indicated that the pilot-scale PSA device could produce qualified product gas and get high CO recovery ratio under optimized conditions. The research may provide reliable fundamental data, for industrial scale utilization of CO, from industrial tail gases, and have strong market competitive power and a broad promoted application prospect.

Pressure swing adsorption modeling of acetone and toluene on activated carbon

A five steps pressure swing adsorption process was designed for acetone and toluene mixtures separation and recovery. Dynamic distributions of gas phase content and temperature were investigated. Based on the theory of Soret and Dufour, a non-isothermal mathematical model was developed to simulate the PSA process. Effects of heat and mass transfer coefficients were studied. The coupled Soret and Dufour effects were also evaluated. It is found that the heat transfer coefficient has little effect on mass transfer in adsorption stage. However, it has some impacts in desorption stage. The maximum value of C/C0 increases by about 25% as heat transfer coefficient decreases. The temperature variation is less than 0.05 K with the change of mass transfer coefficient, so that the effect of mass transfer coefficient on heat transfer can be ignored. It is also concluded that the Soret and Dufour coupled effects are not obvious in pressure swing adsorption compared with fixed-bed adsorption.

Nitrogen rejection from low quality natural gas by pressure swing adsorption experiments and simulation using dynamic adsorption isotherms

In order to remove N_(2) from low quality natural gas,a mathematical model has been established by Aspen adsorption,using the CH_(4)-selective sorbent silicalite-1 pellets.The dynamic adsorption isotherm was first simulated by breakthrough simulation of a CH_(4)/N_(2) mixture at different adsorption pressures and feed flow rates based on breakthrough experiments.The resulting simulated CH_(4) dynamic adsorption amounts were very close to the experimental data at three different adsorption pressures(100,200,and 300 kPa).Moreover,a single-bed,three-step pressure swing adsorption(PSA)experiment was performed,and the results were in good agreement with the simulated data,further corroborating the accuracy of the gas dynamic adsorption isotherm obtained by the simulation method.Finally,based on the simulated dynamic adsorption isotherm of CH_(4) and N_(2),a four-bed,eight-step PSA process has been designed,which enriched 75%(vol)CH_(4) and 80%(vol)CH_(4) to 95%(vol)and 99%(vol),and provided 99%(vol)recovery.

Progress in Pressure Swing Adsorption Models During the Recent 30 Years

The pressure swing adsorption (PSA) models discussed here are divided into three categories: partialdifferential equation model, electrical analogue model and neural network model. The partial differential equationmodel, including equilibrium and kinetic models, has provided an elementary viewpoint for PSA processes. Usingthe simplest equilibrium models, some influential factors, such as pressurization with product, incomplete purge,beds with dead volume and heat effects, are discussed respectively. With several approximate assumptions i.e.,concentration profile in adsorbent, 'frozen' column, symmetry and heat effects of bed wall, the more complexkinetic models can be simplified to a certain degree at the expense of a limited application. It has also been foundthat the electrical analogue model has great flexibility to handle more realistic PSA processes without any additionalhypothesis.

Comparative study on pressure swing adsorption system for industrial hydrogen and fuel cell hydrogen

In order to improve the design of PSA system for fuel cell hydrogen production,a non-isothermal model of eight-bed PSA hydrogen process with five-component(H_(2)/N_(2)/CH_(4)/CO/CO_(2)=74.59%/0.01%/4.2%/2.5%/18.7%(vol))four-stage pressure equalization was developed in this article.The model adopts a composite adsorption bed of activated carbon and zeolite 5 A.In this article,pressure variation,temperature field and separation performance are stimulated,and also effect of providing purge(PP)differential pressure and the ratio of activated carbon to zeolite 5 A on separation performance in the process of producing industrial hydrogen(CO content in hydrogen is 10μl·L^(-1))and fuel cell hydrogen(CO content is 0.2μl·L^(-1))are compared.The results show that Run 3,when the CO content in hydrogen is 10μl·L^(-1),the hydrogen recovery is 89.8%,and the average flow rate of feed gas is 0.529 mol·s^(-1);When the CO content in hydrogen is 0.2μl·L^(-1),the hydrogen recovery is 85.2%,and the average flow rate of feed gas is 0.43 mol·s^(-1).With the increase of PP differential pressure,hydrogen recovery first increases and then decreases,reaching the maximum when PP differential pressure is 0.263 MPa;With the decrease of the ratio of activated carbon to zeolite 5 A,the hydrogen recovery increases gradually.When the CO content in hydrogen is 0.2μl·L^(-1) the hydrogen recovery increases more obviously,from 83.96%to 86.37%,until the ratio of activated carbon to zeolite 5 A decreases to 1.At the end of PP step,no large amount of CO_(2) in gas or solid phase enters the zeolite 5 A adsorption bed,while when the CO content in hydrogen is 10μl·L^(-1),and the ratio of carbon to zeolite 5 A is less than 1.4,more CO_(2) will enter the zeolite 5 A bed.

Hydrogen Purification Performance of Pressure Swing Adsorption Based on Cu-BTC/zeolite 5A Layered Bed

A pressure swing adsorption (PSA) hydrogen purification model for the four-component gas (H_(2)/CO_(2)/CH_(4)/CO=73/16/8/3 mol%) in a layered bed packed with Cu-BTC and zeolite 5A was established to achieve better hydrogen purification performance.By comparing its simulation results with the experimental data,the adsorption isotherm model was validated and could be used to accurately describe the adsorption process of the gas mixture on the two adsorbents.The breakthrough curves of the mixed gas on the layered bed were studied to verify the correctness of the established simulation models.Based on the validated model,the performance of the PSA system based on the layered bed was carried out,including the hydrogen purity and recovery.The simulation results show that the hydrogen purification system based on the layered bed model can achieve hydrogen purity of 95.469% and hydrogen recovery of 83.219%.Moreover,a parametric study was carried out and its results show that reductions in feed flow rate and adsorption time result in an increase in hydrogen purity and a decrease in hydrogen recovery.A longer equalization time between the two adsorption beds can simultaneously increase the hydrogen purity and recovery.

Study on Pressure Swing Adsorption Removing C_(2)^(+) from Natural Gas as Raw Material for Thermal Chlorination

The experimental investigation demonstrates that a satisfactory result can be expected for pressure swing adsorption (PSA) purification of natural gas as raw material for thermal chlorination process. Using hh-4 molecular sieve as adsorbent for removing C+2 components, the suitable adsorption pressure is 0.4-0.45 MPa, desorption vacuum is 0.08-0.09 MPa and circulation time is 20-21 min.

Analysis of CO₂Pressure Swing Adsorption Simulation by Considering the Transport Phenomena in the Adsorber

This study focused on CO2 separation technology with adsorption. This paper describes the analysis carried out by a CO2 pressure swing adsorption simulation to scale up the absorber. An unsteady one-dimensional balance model was constructed by considering the material, energy, and momentum. In the CO2 breakthrough test, the beginning time and CO2 concentration at outlet of CO2 breakthrough in the calculation were almost equivalent to that of experiment results. The correlation consistency of the calculation results with the analysis model and the experimental results obtained by a bench scale experiment was evaluated. The transport phenomena in the adsorber were investigated at the adsorption, rinse, and desorption steps according to the calculation results. The starting time of CO2 breakthrough obtained by the analysis is equal to that obtained by the adsorption breakthrough experiment. This confirms that the CO2 adsorption, and the temperature and velocity distribution in the adsorber, change as a function of the adsorption, rinse, and desorption steps, respectively. Additionally, the CO2 concentration of the captured gas and the amount of CO2 quantity were 93.4% per day and 2.9 ton/day, respectively. These values are equal to those obtained by the bench scale experiment.

高压变压吸附(PSA)技术在甲醇驰放气回收氢气中的运用研究

本文致力深入研究和探讨高压变压吸附(PSA)技术在甲醇驰放气回收氢气中的应用潜力与效果。通过理论分析、实验验证及经济成本考量,本文详细阐述了PSA技术如何有效提高氢气回收效率,降低能源消耗,减少环境污染,为相关企业带来显著的经济效益。此外,本文还展望了PSA技术在未来的发展前景和改进方向,旨在为推动清洁能源的发展和应用提供有价值的参考。

基于Aspen Adsorption模拟软件解析二塔六步变压吸附工艺

变压吸附作为一种新型的气体分离技术,在煤化工气体净化过程中受到化工技术人员的广泛关注。《化学工艺学》教材中针对变压吸附技术只做了简单的文字说明,没有分析其工艺流程。本文利用Aspen Adsorption模拟软件,以二塔六步式吸附工艺流程为例,对变压吸附工艺过程进行解析,以便学生深入了解变压吸附工艺的基本原理和过程。

基于Aspen Adsorption的乙醇变压吸附脱水工艺模拟

以84.2%(x)的乙醇蒸气为原料,基于Aspen Adsorption软件,研究了乙醇变压吸附脱水工艺,得到不同时刻吸附剂水吸附量轴向分布,并通过求解吸附塔利用率确定了乙醇变压吸附脱水工艺的操作周期,考察了吸附压力、吸附剂体积对乙醇变压吸附脱水工艺的影响。实验结果表明,乙醇变压吸附脱水的吸附周期与吸附塔在不同时刻水的吸附量有关,确定乙醇变压吸附脱水的操作周期为15 800 s;吸附塔的利用率为1时,吸附塔吸附饱和,出口气组成和原料气组成相同;提高乙醇变压吸附脱水的操作压力可增加吸附塔的气体处理量,但同时增加了原料气预热的能耗;吸附剂体积增大时,扩散对传质系数的影响增大,需减少模拟所用传质系数。

Carbon Dioxide/Methane Separation by Adsorption on Sepiolite

In this work, the use of sepiolite for the removal of carbon dioxide from a carbon dioxide/methane mixture by a pressure swing adsorption （PSA） process has been researched. Adsorption equilibrium and kinetics have been measured in a fixed-bed, and the adsorption equilibrium parameters of carbon dioxide and methane on sepiolite have been obtained. A model based on the LDF approximation has been employed to simulate the fixed-bed kinetics, using the Langmuir equation to describe the adsorption equilibrium isotherm. The functioning of a PSA cycle for separating carbon dioxide/methane mixtures using sepiolite as adsorbent has also been studied. The experimental results were compared with the ones predicted by the model adapted to a PSA system. Methane with purity higher than 97% can be obtained from feeds containing carbon dioxide with concentrations ranging from 34% to 56% with the proposed PSA cycle. These results suggest that sepiolite is an adsorbent with good properties for its employment in a PSA cycle for carbon dioxide removal from landfill gases.

PSA-低温甲醇洗-膜分离耦合的氢气分离系统建立与模拟

氢能作为实现可持续发展的重要载体,对构建清洁低碳高效的能源体系、实现“双碳”目标具有重要意义。通过提出变压吸附(PSA)-低温甲醇洗-膜分离的耦合氢气分离系统,并借助Aspen Plus等软件进行模拟和分析,实现了多种分离技术的优势结合。多项分离工艺集成有效利用了PSA尾气中的氢气,提高了氢气回收率;打破了单一膜分离提纯氢气的纯度瓶颈,获得产品氢气浓度高达99.67%;实现了CO_(2)的富集和CH_(4)的循环回收,减少了制氢原料的损失。整个系统相比于现存的装置运行分离效果和经济性更好,为其他氢气提纯问题提供了新思路和一定的实用价值。

大型变压吸附制氧(VPSA)装置在粤钢的应用实践

从技术方案的选择及运行管控等方面介绍了大型VPSA制氧系统在粤钢的实践。并阐述了优化设计及对运行单位电耗进行了分析,该系统的投产大大降低了粤钢的用氧成本,助力高炉生产工序实现增产降本目标。

PSA变压吸附技术在合成氨中的应用分析

在合成氨生产过程中存在着PSA提氢处理能力弱、氢气损耗量大的不足。以8.8万t/a合成氨PSA变压吸附技术为核心,对变压吸附技术方案进行了优化。通过氮气再生+微动力回收方案解决了传统变压吸附过程中气体损坏量大的问题。根据实际应用表明,新的变压吸附技术能够将系统排气口位置的二氧化碳体积分数降低到0.1%以下,氢气的回收率提升到了99.2%,极大地提升了合成氨过程中的气体利用率和经济性。

钢铁行业二氧化碳捕集技术研究及应用进展

钢铁行业碳减排对我国实现双碳目标具有重要意义,也是国家实现碳中和承诺的主战场之一。系统综述了钢铁行业碳捕集技术的研究及应用进展,总结了钢铁行业碳排放特征,其中高炉炼铁工序是钢铁行业碳排放量最高的工序,其CO_(2)直接排放主要来源于高炉热风炉,占比高达30%左右。钢铁行业的碳捕集技术主要包括有机胺吸收技术、氨水吸收技术、变压吸附技术和钢渣矿化技术,但目前应用案例较少且规模普遍偏小。此外,还对新型有机胺吸收剂、改性分子筛材料等碳捕集材料的研究进展进行了系统总结。未来的研究应重点关注高炉煤气以及高炉热风炉烟气中的CO_(2)捕集,加强对相变吸收体系和催化辅助再生体系的研究,以解决吸收剂分相性能和黏度之间的平衡问题及催化剂稳定性问题,促进两者耦合应用;加强CO_(2)捕集利用一体化技术的研究,重点关注烟气-钢渣直接矿化技术和吸收-矿化一体化技术。

氮掺杂的碳基吸附剂高效分离甲烷/氮气

采用变压吸附(PSA)高效分离甲烷和氮气是实现甲烷富集和回收的重要手段之一,其核心是高性能吸附剂的制备。本研究以三聚氰胺(M)为氮源,采用水热法合成了五种不同三聚氰胺和间苯二酚(R)质量比的间苯二酚树脂基吸附材料MRF-AC_(n)。运用容量法测试303K,0~0.7MPa下甲烷和氮气的吸附性能,低温(77 K)氮吸脱附法对材料的孔结构进行表征,分别用Langmuir Freundlich(LF)模型和准二阶动力学(PSO)模型拟合甲烷和氮气的吸附等温线数据和动力学数据。结果表明,氮元素的引入调节了吸附材料的孔结构,不同程度增加了吸附材料的比表面积和微孔孔容,增加了吸附材料的极性,从而改变了甲烷和氮气的吸附量,其中样品MRF-AC_(2)表现出更好的甲烷和氮气吸附和分离性能,吸附量分别为45.20和22.23mL·g^(-1)分离比最高达到10以上。

常温法组合工艺在零散气BOG提氦中的应用研究

针对零散气橇装LNG装置BOG中氦资源回收工艺,在调研国内外常温法提氦工艺技术的基础上,创新性提出了膜分离+变压吸附进行氦气回收的工艺路线。采用模拟计算的方法,对4种工艺的特点和适应性进行了对比分析;建立试验装置,对不同的膜组件进行了不同原料气氦含量、不同进膜压力、不同进膜流量下的试验研究。与传统深冷法提氦工艺相比,常温法提氦的工艺流程缩短、单位产品能耗降低、投资成本明显减少,能较好地适应零散气BOG中氦资源回收的场景。

变压吸附分离技术在催化干气乙烯回收中的应用

介绍了深冷分离技术、吸收分离技术和变压吸附分离技术3种催化干气乙烯回收技术。某石化公司炼油结构调整,催化干气产能由15×10^(4) t/a扩至21×10^(4) t/a,考虑变压吸附分离技术操作简单、无需辅助原料,操作条件变化后装置运行能快速平稳,以及综合能耗低等优势,仍继续采用该技术。根据扩能改造设计原则,将原两段法工艺改为一段法工艺,并将同时处于抽空步骤的塔数由2塔增加为3塔,处于吸附步骤的塔数由4塔增加为5塔。结果表明,产品质量相当时,扩能改造后综合能耗降低约14%,运行指标优于改造前。在减少碳排放的背景下,变压吸附分离技术因综合能耗低于其他技术,更具应用优势。