变压吸附提纯一氧化碳工艺系统的优化运行

介绍醋酐装置水煤气变压吸附提纯一氧化碳工艺系统,分析系统运行中出现的问题,提出具体的优化改造措施,改造后使整个系统实现了安全、稳定、长周期效益运行。     

Cycle synthesis and optimization of a VSA process for postcombustion CO2 capture

A systematic analysis of several vacuum swing adsorption (VSA) cycles with Zeochem zeolite 13X as the adsorbent to capture CO₂ from dry, flue gas containing 15% CO₂ in N₂ is reported. Full optimization of the analyzed VSA cycles using genetic algorithm has been performed to obtain purity‐recovery and energy‐productivity Pareto fronts. These cycles are assessed for their ability to produce high‐purity CO₂ at high recovery. Configurations satisfying 90% purity‐recovery constraints are ranked according to their energy‐productivity Pareto fronts. It is shown that a 4‐step VSA cycle with light product pressurization gives the minimum energy penalty of 131 kWh/tonne CO₂ captured at a productivity of 0.57 mol CO₂/m³ adsorbent/s. The minimum energy consumption required to achieve 95 and 97% purities, both at 90% recoveries, are 154 and 186 kWh/tonne CO₂ captured, respectively. For the proposed cycle, it is shown that significant increase in productivity can be achieved with a marginal increase in energy consumption. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4735–4748, 2013     

Large‐scale optimization strategies for pressure swing adsorption cycle synthesis

Pressure swing adsorption (PSA) is an efficient method for gas separation and is a potential candidate for carbon dioxide (CO₂) capture from power plants. However, few PSA cycles have been designed for this purpose; the optimal design and operation of PSA cycles for CO₂ capture, as well as other systems, remains a very challenging task. In this study, we present a systematic optimization‐based formulation for the synthesis and design of novel PSA cycles for CO₂ capture in IGCC power plants, which can simultaneously produce hydrogen (H₂) and CO₂ at high purity and high recovery. Here, we apply a superstructure‐based approach to simultaneously determine optimal cycle configurations and design parameters for PSA units. This approach combines automatic differentiation, efficient ODE solvers for the state and sensitivity equations of the PSA model, and state of the art nonlinear programming solvers. Three optimization models are proposed, and two PSA case studies are considered. The first case study considers a binary separation of H₂ and CO₂ at high purity, where specific energy is minimized, whereas the second case study considers a larger five component separation. © 2012 American Institute of Chemical Engineers AIChE J, 58: 3777–3791, 2012     

Optimization and Control of Pressure Swing Adsorption Processes Under Uncertainty

The real‐time periodic performance of a pressure swing adsorption (PSA) system strongly depends on the choice of key decision variables and operational considerations such as processing steps and column pressure temporal profiles, making its design and operation a challenging task. This work presents a detailed optimization‐based approach for simultaneously incorporating PSA design, operational, and control aspects under the effect of time variant and invariant disturbances. It is applied to a two‐bed, six‐step PSA system represented by a rigorous mathematical model, where the key optimization objective is to maximize the expected H₂ recovery while achieving a closed loop product H₂ purity of 99.99%, for separating 70% H₂, 30% CH₄ feed. The benefits over sequential design and control approach are shown in terms of closed‐loop recovery improvement of more than 3%, while the incorporation of explicit/multiparametric model predictive controllers improves the closed loop performance. © 2012 American Institute of Chemical Engineers AIChE J, 59: 120–131, 2013     

吸咐分离联合工艺

通过典型应用实例介绍了各种吸附分离的联合工艺及其应用前景。     

变压吸附数值模拟的研究

从变压吸附的控制方程入手,分析了瞬时平衡模型、线性推动力模型以及孔扩散模型,并对软件化模拟变压吸附系统进行了论述。利用三维流体力学模拟软件,可以模拟并优化吸附塔的气体分布器及其他塔内件,优化程控阀的流体力学性能;利用一维流体力学模拟软件,可以对变压吸附系统管网仿真与优化。利用大型商用软件对变压吸附系统进行从微观的流动细节模拟到宏观的运行状态模拟,是变压吸附数值模拟和系统优化的发展方向。     

快速变压吸附制氧动态传质系数模拟分析

研究快速变压吸附制氧过程中的传质过程,结合实验数据对全局动态传质系数与常数传质系数进行对比模拟分析,并考察各传质阻力对传质效果的影响。结果表明：基于轴向、膜扩散和孔扩散估算的动态传质系数是有效的。膜阻力是主要阻力,其次是轴向扩散阻力,大孔扩散阻力较小,微孔扩散阻力可忽略。在快速变压吸附中,由于气速和温度变化较快,传质系数也会有较大变化,总体趋势是传质系数随着温度和气速的升高而升高。采用恒定传质系数无法准确描述吸附塔内各个时间点、空间点上的传质行为,根据各节点状态计算出的动态估算传质系数能够与吸附塔内的行为有较好的吻合度,模型具有较高的可信性。     

新型变压吸附技术的开发和应用

简要介绍了新型两段法变压吸附高效气体分离技术开发的背景及意义,详细介绍了该技术在脱碳、提氢、提纯CO、制氧领域中的应用。该技术的开发成功,极大地简化了工艺流程,既节省动力设备购置费、运行费和设备维护费,又大幅提高了装置稳定性、安全性和可靠性。     

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。     

变压吸附装置均压压力及管径计算的探讨

本文系统地推导了变压吸附过程中均压压力和管道流速的计算公式,结合均压压力的理论计算值与实际开车数据并进行对比,引入吸附放大系数对管径计算进行修正,为变压吸附管径设计和现场开车数据定量分析提供理论基础。     

变压吸附脱碳装置在氮肥生产中的应用

介绍变压吸附脱碳的基本原理、设计参数、工艺流程及主要设备,系统的运行情况及优化改造措施。     

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。     

Equilibrium Analysis of Cyclic Adsorption Processes: CO2 Working Capacities with NaY

Abstract

The most common application of adsorption is via pressure swing adsorption. In this type of design, the feed and regeneration temperatures are kept approximately equal, whereas the feed pressure is higher than the regeneration pressure. By exploiting the difference in the amount adsorbed at a higher pressure to the amount adsorbed at a lower pressure, a working capacity is realized. Therefore, by examining the expected (ideal) working capacity of an adsorbent, a performance characteristic can be analyzed for a pressure swing adsorption process (PSA). For this work, feed pressures up to 2.0 atm CO₂ and feed temperatures from 20°C to 200°C were investigated. These limits were chosen due to the nature of the target process: CO₂ removal from flue gas.

Carbon dioxide adsorption isotherms were determined in a constant volume system at 23°C, 45°C, 65°C, 104°C, 146°C, and 198°C, for pressures between 0.001 and 2.5 atm CO₂ with NaY zeolite. These data were fit with the temperature dependent form of the Toth isotherm. Henry's Law constants and the heat of adsorption at the limit of zero coverage were also determined using the concentration pulse method. Comparison of the Henry's Law constants derived from the Toth isotherm, and those obtained with the concentration pulse method provided excellent agreement.

By using the Toth isotherm, expected working capacity contour plots were constructed for PSA (Pressure Swing Adsorption), TSA (Temperature Swing Adsorption), and PTSA (Pressure Temperature Swing Adsorption) cycles. The largest expected working capacities were obtained when the bed was operated under a high‐pressure gradient PSA cycle, or a high thermal and pressure gradient PTSA cycle. The results also showed that certain TSA and PSA cycle conditions would result with higher expected working capacities as the feed temperature increases.     

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。     

采用新型吸附剂及变温变压吸附技术脱除氯乙烯单体中的水分

介绍了采用新型吸附剂及变温变压吸附技术脱除氯乙烯单体中水分的原理及工艺流程。该技术用于20万t/a氯乙烯单体装置的深度脱水处理后,氯乙烯单体的含水质量分数由700μg/g下降到20~50μg/g。该技术脱水能力强、效率高,生产过程中无"三废"排放。     

变压吸附过程的数学模拟

变压吸附过程的数学模拟崔群姚虎卿（南京化工大学，南京２１０００９）关键词变压吸附（ＰＳＡ）数学模拟１前言变压吸附过程具有常温操作、易于自控、可获得高纯度产品等特点。广泛用于炼油和石油化工过程尾气的回收等系统，如用于炼油厂放空气和合成氨厂弛放气的Ｈ２...     

New development in flow‐through pressure‐swing frequency response method for mass‐transfer study: Ethane in ZIF‐8

A new pressure‐swing frequency response (PSFR) method has been developed to study mass transfer in adsorption systems as a function of temperature and pressure, from ?70 to 180°C, and up to 7 bar. New in‐phase and out‐of‐phase functions have been derived for the PSFR in a general way to allow information extracted from it independent of whether the system is operated in a batch volume swing or a flow‐through pressure swing mode. A new mathematical model that considers distribution of diffusion rates has been introduced to account for diffusive transport in heterogeneous samples. Numerical simulation results have shown that a single rate diffusion model works well when heterogeneity can be described by a normal distribution, but not for asymmetrically bimodal distributions. As a test reference system, the transport of ethane in ZIF‐8 was investigated at different pressures and temperatures using the new PSFR method. The mass transfer was found to be dominated by micropore diffusion. Diffusivity was found to be weakly dependent on pressure or loading, but quite strongly dependent on temperature. The results agree very well with our independent batch volume frequency response technique experiments. © 2016 American Institute of Chemical Engineers AIChE J, 63: 1077–1090, 2017     

变压吸附制氮机均压方式的研究

简述了变压吸附制氮装置工艺流程、工作过程和均压方式.介绍了对变压吸附制氮装置等势平衡均压、不等势平衡均压、等势不平衡均压、不等势不平衡均压方式的实验结果,着重介绍了等势不平衡均压方式的特点.     

变压吸附法回收氢气

介绍了变压吸附法回收氢气的原理、工艺流程、运行方式等,并分析了运行效果和经济效益。