基于双回流变压吸附工艺的空气分离模拟及分析

双回流变压吸附是一种在吸附塔中间位置进料,塔顶和塔底分别采用轻、重组分回流的变压吸附过程,能够同时生产两种高纯度、高回收率的产品气。以实验室自主合成的LiLSX分子筛为吸附剂,利用Aspen Adsorption模拟软件,对进料组成为78%N₂/21%O₂/1%Ar的实际空气进行了两塔双回流变压吸附的模拟研究。模拟结果表明：当原料气为78%N₂/21%O₂/1%Ar,吸附压力为2 bar(1 bar=10⁵ Pa),解吸压力为0.3 bar,进料量为0.4 m³/h,轻组分回流流量为0.095 L/min,重组分回流流量为5.22 L/min时,能够得到体积分数为95.67%的O₂和体积分数为98.25%的N₂,回收率分别为94.60%和99.91%。并且进一步探究了进料位置、吸附时间、轻组分回流流量、重组分产品气流量等因素对O₂和N₂两种产品气纯度和回收率的影响。     

变压吸附空分制氧非等温过程模拟

就变压吸附空气分离制氧过程,对接近真实情况的非线性、非等温模型构成的偏微分方程组,采用正交配置进行空间离散化和三阶半隐式龙格 库塔法的数值计算方法,研究了变压吸附过程中床层内温度和浓度的动态行为,考察了清洗比、吸附压力、进气流量、吸附时间等操作参数对过程性能的影响,为过程优化设计建立基础。     

变压吸附分离技术推广应用研究

概述了变压吸附分离技术的推广应用情况，介绍了具体的成果推广方式，对变压吸附技术创造的经济效益和社会效益做了分析     

真空变压吸附沼气净化过程的仿真研究

真空变压吸附(VPSA)是一种气体分离技术,该技术运用在沼气净化过程还存在较多的问题,针对该过程吸附塔出口浓度出现的浓度峰问题,运用线性推动力模型(LDF)与Langmuir等温方程对其建立了数学模型,模拟分析了缓冲罐中杂质浓度对吸附步骤出口浓度的影响。结果表明:相同吸附时间下,随着吸附压的降低,二均降结束时会有更多的杂质进入缓冲罐,而缓冲罐中的杂质又会通过一均升步骤进入吸附塔,最终使得吸附步骤出口浓度曲线出现波峰,从而影响了吸附塔出口CH₄含量。通过模型的分析,吸附时间随着吸附压不断降低而缩短,可以有效控制杂质进入缓冲罐,从而使吸附塔出口CH₄含量提高。     

变压吸附技术净化分离有机蒸气的研究进展

从变压吸附分离回收低沸点和中高沸点有机蒸气、变压吸附用吸附剂以及变压吸附分离回收有机蒸气工艺及其过程的计算机模拟等方面,评述了变压吸附技术在净化分离有机蒸气方面的研究进展。指出今后的研究方向为:新型变压吸附用吸附剂;多种分离过程的集成技术;过程优化设计;智能型控制系统;多成分有机气体的变压吸附分离;利用计算机进行变压吸附过程模拟的基础研究;吸附和脱附的传质、传热基础理论等。     

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。     

Anatomy of a rapid pressure swing adsorption process performance

A detailed numerical study of the individual and cumulative effects of various mass, heat, and momentum transfer resistances, which are generally present inside a practical adiabatic adsorber, on the overall separation performance of a rapid pressure swing adsorption (RPSA) process is performed for production of nearly pure helium gas from an equimolar binary (N₂ +He) gas mixture using 5 A zeolite. Column bed size factor (BSF) and helium recovery (R) from the feed gas are used to characterize the separation performances. All practical impediments like column pressure drop, finite gas‐solid mass and heat transfer resistances, mass and heat axial dispersions in the gas phase, and heats of ad(de)sorption causing nonisothermal operation have detrimental impacts on the overall process performance, which are significantly accentuated when the total cycle time of a RPSA process is small and the product gas helium purity is high. These impediments also prohibit indefinite lowering of BSF (desired performance) by decreasing process cycle time alone. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2008–2015, 2015     

分子筛对CH_4/空气混合气的变压吸附分离研究

为提高煤层气变压吸附浓缩效果,以一种商品分子筛为对象,研究了该分子筛在小型四塔变压吸附装置上的CH4/空气混合气浓缩分离效果,分析了吸附时间、吸附压力以及原料气浓度对混合气浓缩效果的影响。结果表明,吸附时间过长或吸附压力过高,均不利于获得较好的产品气浓度及回收率。吸附时间180 s,吸附压力300 k Pa时,试验商品分子筛对CH4/N2的浓缩分离效果最佳。其中,10%浓度原料气提浓至30.56%,提高约20%,产品气中CH4回收率达到94.45%,对原料气的处理量达到67.77 m3/(t·h);35%浓度原料气提浓至76.33%,提高约40%,产品气中CH4回收率达到69.68%,对原料气的处理量达到68.99 m3/(t·h);65%原料气提浓至89.18%,提高约25%,产品气中CH4回收率达到87.22%,对原料气的处理量达到83.36 m3/(t·h)。     

热集成变压精馏乙二醇脱水系统的控制方案优化

针对热集成变压精馏乙二醇脱水再生系统存在的操作不稳定等问题,基于Aspen Plus和Aspen Dynamics软件,在全流程稳态模拟的基础上,对其进行了动态模拟及控制方案优化。设计了改进型控制方案CS2,与常规控制方案CS1相比,两个塔的操作压力的控制回路是相互独立的,高压塔的塔釜液位由再沸器的导热油流量控制,低压塔的塔釜温度由塔釜的采出流量控制,再分别对进料流量和进料组成中乙二醇含量的阶跃变动的动态响应特性进行分析。结果表明,控制方案CS1基本能够抵抗进料流量和进料组成扰动对系统的影响,但相关控制响应会出现一定的滞后性,难以保证产品满足要求。改进的控制方案CS2对相同的进料流量和进料组成扰动有更好的抵抗能力,控制性能显著提高,保证乙二醇的质量分数不低88%,趋于稳定时产品质量变化幅度小于2%,且该方案在实际应用中涉及到的操作相对简单。本文为相关双塔耦合过程的稳定控制提供了一种新思路,对于双塔耦合在其他体系的工程应用也有借鉴作用。     

规整复合吸附剂真空变压吸附分离CH4/N2工艺模拟与分析

为减少甲烷排放,实现低浓度煤层气有效资源化利用,探究了使用规整复合吸附剂真空变压吸附富集低浓度煤层气的工艺。采用静态容积法测定了甲烷、氮气在规整复合吸附剂上的吸附等温线,同时建立了包括质量、热量和动量守恒在内的严格吸附床数学模型,设计了三塔连续进料的真空变压吸附工艺并进行模拟。分析了工艺达到循环稳态后吸附床层轴向温度分布和压力变化,并且探究了进料量、解吸压力、原料气中甲烷浓度和吸附压力对纯度、回收率、工艺能耗和吸附剂产率等工艺性能的影响。模拟结果表明,在进料量为100 L·min^-1,解吸压力为0.1 bar（1 bar=0.1 MPa）,原料气甲烷浓度为30%,吸附压力为3 bar时可以生产纯度为59.07%,回收率为93.64%的富CH₄产品气,同时单位能耗为18.70 kJ·mol^-1,吸附剂产率为4.56 mol·h^-1·kg^-1。表明规整吸附剂对CH₄/N₂具有良好的吸附分离效果,能够实现低浓度煤层气中甲烷高效富集。     

真空变压吸附分离含氧煤层气的工艺参数实验研究

针对真空变压吸附富集低浓度含氧煤层气,对工艺参数和吸附塔结构进行了优化试验研究。实验结果标明,在一定的时间范围内,随着吸附时间的延长,解吸气和排放气中甲烷体积分数逐渐增大,而排放气中的氧气体积分数则小幅度降低;反吹步骤可以降低排放气中甲烷和氧气的体积分数,但反吹步骤也会降低解吸气中甲烷的体积分数;保持吸附剂不变,吸附塔高径比由3.7增大到13.3,解吸气中甲烷体积分数增大了2.1%,排放气中甲烷体积分数降低了1%。可以为低浓度含氧煤层气富集的实际应用提供参考。     

Performance of a medical oxygen concentrator using rapid pressure swing adsorption process: Effect of feed air pressure

The effects of feed air pressure on the steady‐state performance of a medical oxygen concentrator (MOC) were experimentally evaluated using a novel design of a MOC unit which produced a continuous stream of ～90% O₂ employing a rapid pressure swing adsorption (RPSA) process scheme. Dry, CO₂ free air containing ～1% Ar at different feed gas pressures was used in the tests in conjunction with a commercial sample of LiLSX zeolite as the N₂ selective adsorbent in the process. The bed size factor (BSF) can be systematically reduced by increasing the feed air pressure for any given total cycle time. The effect of feed air pressure on the oxygen recovery (R) is, however, more complex; it increases with increasing feed pressure only at longer cycle times while the effect is marginal at shorter cycle times. The BSF cannot be indefinitely reduced by lowering total process cycle time at any pressure—a minimum is exhibited in the BSF‐cycle time plot. The minimum value of the BSF decreases as the feed pressure is increased. The cycle time for the minimum BSF is, however, not significantly altered by the feed pressure in the data range of this work. © 2015 American Institute of Chemical Engineers AIChE J, 62: 1212–1215, 2016     

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%。     

Separation of methane and nitrogen using ionic liquidic zeolites by pressure vacuum swing adsorption

The separation of methane (CH₄) and nitrogen (N₂) is a significant challenge to the enrichment and utilization of low concentration CH₄ due to the similarity in the physical and chemical properties of the two molecules. In this work, we investigated the separation of CH₄ from N₂ using 100 kg of a new ionic liquidic zeolite (ILZ) material in a 6-bed pilot-scale pressure swing adsorption process. Feed gases with CH₄ concentrations of 5.0% and 16.1% were upgraded to 11.5% and 34.6%, respectively, with CH₄ recoveries higher than 80%. The pilot test results were used to anchor a numerical model that then allowed the efficient investigation of multiple operational parameters including desorption pressure and feed gas flow rates. The numerical model produced CH₄ concentrations for both product streams consistent with those measured in the pilot experiments, with root mean square deviations below 2%. The modeling results revealed that sufficiently low desorption pressures can unexpectedly lead to lower heavy product purities under limited feed gas flow conditions. Furthermore, the optimum feed gas flow rate under which maximum heavy product purity is achieved increases with lower desorption pressure. The maximum CH₄ concentrations increased from 31.8% to 41.5%, as desorption pressures decreased from 22.8 to 12.2 kPa for optimum feed flow rates between 78.2 and 105.5 mol/h. We also demonstrate a method of process optimization based on the bed capacity ratio, ℂ, which provides a scale-independent measure of the degree to which the column is being used effectively. By varying feed flow rate and/or desorption pressure, ℂ values between 0.2 and 0.8 were explored, with maxima in the combined separation performance metric (methane recovery) × (methane purity) occurring for values of ℂ in the range 0.29–0.36. This separation performance optimization by adjusting ℂ provides an effective strategy for integrating and understanding the impact of multiple operating parameters.     

工业尾气变压吸附提纯一氧化碳中试

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.     

快速变压吸附制氢工艺的模拟与分析

目前工业上主要通过变压吸附技术从蒸汽甲烷重整气中制取氢产品气。然而,能源需求量的快速增加使得传统变压吸附技术在产量方面的不足越发明显。为此,进行了快速变压吸附从蒸汽甲烷重整气中制取氢气的模拟研究。采用活性炭和5A分子筛作为吸附剂,并以测得的原料气中各组分在两种吸附剂上的吸附数据为基础,进行了六塔快速变压吸附工艺的数值模拟与分析。在分析了塔内温度、压力和固相的浓度分布后,探究了进料流量、双层吸附剂高度比以及冲洗进料比三个操作参数对于快速变压吸附工艺性能的影响,结果表明：原料气组成为H₂/CH₄/CO/CO₂=76%/3.5%/0.5%/20%,吸附压力为22 bar（1 bar=10⁵ Pa）,解吸吹扫压力为1.0 bar,处理量为0.8875 mol·s^-1,吸附剂床层高度比为0.5∶0.5,冲洗进料比为22.37%时,可获得H₂纯度99.90%,回收率69.88%,此时H₂产量为0.4713 mol·s^-1。相比之下,氢气纯度为99.90%时,尽管PSA工艺回收率为83.40%,但处理量只有0.39 mol·s^-1,因此H₂产量仅为0.2472 mol·s^-1。     

真空变压吸附空分制氧等温与非等温过程模拟比较

应用动态柱穿透法测定的空气中氮-氧吸附平衡数据模拟两床真空变压吸附(VSA)空分制氧中等温与非等温过程;在VSA过程模拟中探讨了吸附压力、进料流量和冲洗比等过程操作条件以及吸附过程中温度的变化对产品气氧的纯度、收率和产率的影响,为VSA空分制氧过程提供一定的设计依据。     

真空变压吸附分离CH4/N2/O2实验、模拟与安评

针对CH₄/N₂/O₂混合物脱氧效果差以及安全性低等问题,采用实验室自制活性炭为吸附剂,通过数值模拟和实验进行了双塔真空变压吸附（VPSA）分离25% CH₄/59% N₂/16% O₂混合物的工艺研究。通过考察进料流量和置换流量对甲烷产品纯度和回收率的影响,实验验证了数值模型的准确性。在模拟和实验的基础上,对VPSA工艺全流程进行了系统的安全性分析,并针对存在安全隐患的过程,提出一种更为安全的VPSA工艺流程。研究结果表明,通过双塔VPSA可以获得甲烷纯度为51.36%的产品气,甲烷回收率可达85.65%,存在安全隐患的过程主要集中在吸附、均压和终升压步骤,通过原料气的惰化过程,可以实现VPSA工艺的安全操作。     

变压吸附分离工业废气二氧化碳的研究进展

概述了未来人类对过量二氧化碳排放的处理办法,即碳的捕获和存储(CCS).简介了4种二氧化碳的分离工艺及特点和工业中二氧化碳的捕获系统.阐述了变压吸附工艺的基本原理和其在捕获工业废气中二氧化碳上的应用,以及变压吸附分离二氧化碳的工艺在循环结构设计、吸附剂材料和数值模拟等方面的研究进展和国内外的工业化应用.分析了目前该工艺仍存在的问题,指出该技术具有广阔的应用前景.     

变压吸附氢气纯化过程瞬态分析

变压吸附技术是工业上生产高纯氢气最常用的方法之一。然而,在实际生产过程中无法观察到塔内各组分在不同时刻的分布状态,因此借助模拟的手段来研究从投料至系统达到循环稳态期间各组分在塔内的动态变化规律,进而指导工艺改进是很有必要的。采用活性炭和5A分子筛为吸附剂,设计了八塔变压吸附工艺从蒸汽甲烷重整气中纯化氢气,模拟了变压吸附制氢开车过程,分析了开车过程中塔内各组分在吸附、顺放以及冲洗三个阶段以及循环稳态后吸附阶段瞬态吸附行为和塔内温度变化。结果表明,在吸附以及顺放等过程中重组分会随着循环周期向塔顶移动。这一现象是组分间竞争吸附和冲洗再生方式下重组分在床层底部累积两个作用因素共同导致的。这些因素在一定程度上也会造成CO的吸附前沿在吸附阶段就过多进入5A分子筛上,使得CO含量成为限制工艺性能的主要因素。