Simulation and optimization of the thermally coupled reactive distillation column for producing toluene diisocynate

Toluene diisocyanate is an important chemical intermediate prepared by phosgenation reaction with two steps named cold and thermal phosgenation, respectively. The thermal phosgenation reaction is a complex reactive distillation process with high energy consumption and multiple targets of reaction and separation, so it is of great significance to optimize the step. The reactive distillation model of the thermal phosgenation was established for an industrial installation by aspen plus, and the effects of the different parameters of temperatures, residence times, etc., were investigated firstly; then a thermally coupled reactive distillation column was presented to perform the thermal phosgenation process, and the optimal operation and configuration parameters were obtained by simulation. The results showed that the proposed process can save the heat and cold energy with 7.29% and 32.78%, respectively, and reduce the total annual cost by about 17.11%.     

内部热耦合空分塔的节能优化分析

内部热耦合精馏是迄今为止所提出的节能效果最好,而唯一没有商业化的节能技术。将内部热耦合技术用于空分塔,可以带来良好的节能效果。根据低温空气分离过程以及三组分精馏的特点,提出了一种新的内部热耦合空分精馏塔优化模型。在优化模型基础上,对热耦合塔进行了深入的节能优化与分析,并且与常规空分仿真结果进行了比较分析,压缩机能耗下降20.75%,产值增加17.46%,单位产值能耗下降32.53%。内部热耦合空分塔的提取率以及能耗均优于常规热耦合空分塔,节能效果显著。     

Nonlinear wave modeling and dynamic analysis of internal thermally coupled distillation columns

Internal thermally coupled distillation column (ITCDIC) is a frontier in the energy saving distillation research. It is well known for the complex dynamics, which challenge the establishment of an excellent reduced model for further control strategy design greatly. In this article, a physical approach of the ITCDIC process based on nonlinear wave theory is explored, where it is first discovered that traditional wave theory in conventional distillation columns (CDIC) could not be directly applied in ITCDIC, due to: First, the internal thermal coupling results in mole flow rates varying evidently over each stage, which not only makes the wave modeling of the wave phenomenon in ITCDIC more difficult but also makes wave dynamics greatly different between ITCDIC and CDIC; Second, an interesting wave phenomenon of ITCDIC is discovered that waves located in the rectifying section and stripping section travel under opposite tendencies when the steady state is disturbed by the step change of thermal condition q, one sharpens and the other is likely to spread synchronously, it means the movement of wave profiles in ITCDIC could not be simply described by shock wave velocity, which is usually used in wave modeling of CDIC; more seriously, shapes of the self‐sharpening wave profiles in ITCDIC change obviously during the traveling processes, which further reveals that shape influence on wave velocity has to be considered in the wave modeling of ITCDIC. A rigorous wave velocity and a natural wave velocity are derived, respectively, based on which, the detailed analyses of traveling wave characteristics are carried out. A novel wave velocity, based on the profile trial function which has been well developed by Marquardt, is further derived to consider the obvious change of profile shape. And a completed nonlinear wave model of ITCDIC is thereby established by combining the proposed wave velocity with thermal coupling relations and material balance relations. The benzene‐toluene system is illustrated as an example, where component concentration prediction and distinct dynamic characteristics are carried out in detail based on the proposed nonlinear wave models. The research results reveal the accuracy and validity of the proposed nonlinear wave model of ITCDIC. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

多能互补协同蓄能系统热力学分析与运行优化

提出了一种多能互补协同蓄能建筑供能系统,该系统将空气源热泵、水源热泵、太阳能热电联产组件以及蓄能技术（蓄冷、蓄热）有效结合,实现了可再生能源的高效利用与建筑的经济供能,利用热力学分析方法对该供能系统进行性能分析与运行优化研究。首先,通过能源监控平台收集该供能系统的实际运行数据建立了系统分析模型,并对冬季典型日工况进行了系统性能分析,结果表明系统运行稳定,其夜间蓄能平均COP和效率分别为2和32.24%,均高于常规系统。接着,通过分析系统冬季实际运行数据,总结出了各蓄能工况的运行规律,并制定了系统优化运行策略。最后,对该多能互补系统进行了热经济学评价,本系统单位面积供热费用仅为12.5 CNY/m²,年单位成本为2.16 CNY/kWh,且相较于常规空气源热泵直供系统和燃气热水锅炉供暖系统,本系统的动态回收期分别为3.66年和2.47年,经济效益优势明显,是值得推广的供能系统形式。     

完全能量耦合精馏塔的设计、模拟与优化

本文针对完全能量耦合精馏塔,基于Fenske-Underwood-Gilliland方程建立了完整的简捷设计方法,得到了各塔的实际理论板数、适宜的进料和侧线液相采出位置以及各塔回流比等参数。并在此基础上通过严格模拟,对完全热耦合精馏塔的中间组分分配比β、气相分割比R_v和液相分割比R_l等参数进行了优化,得出了它们对再沸器热负荷的影响规律。     

Energy savings bottleneck diagnosis of cooling system based on integrated correlation analysis

The circulation cooling system is an important auxiliary system in industry and has great potential for saving energy. However, a holistic energy savings retrofit of the system can cause high costs and a low input–output ratio. To address this problem, this paper integrates grey correlation analysis and partial correlation analysis to propose a new energy savings bottleneck diagnosis method for the circulating cooling system. This method deeply analyzes the operation mechanism of the industrial circulating cooling system and summarizes the main energy-savings factor. Through the energy savings bottleneck diagnosis method based on grey correlation analysis and partial correlation analysis, the energy savings correlation coefficient and energy savings difference coefficient are calculated, and the relationship between each energy savings factor and the specific energy consumption is accurately described and quantified. Furthermore, the system energy savings bottleneck diagnosis is performed and the quantified energy savings priority of each system link is obtained. It can effectively guide the implementation of system energy savings optimization and retrofit. Finally, the effectiveness of the diagnosis method is demonstrated by simulation verification with actual network data.     

合同能源管理方法与建筑节能关系探讨

分析了我国能源利用情况,说明我国建筑行业存在着巨大的节能潜力。节能服务公司的出现和发展,为我国建筑节能提供了新的发展思路。介绍了节能服务公司广泛采用的合同能源管理模式及其优点。节能服务公司为需要节能的单位提供全方位的服务,从能源审计到最后的效益分享,都体现了现代化的服务理念和模式。但是节能服务公司的发展还不是很完善,需要政府部门、相关企业共同合作,从而为我国的节能事业做出贡献。     

电热水器内部结构优化及储能特性研究

将相变储能技术应用于电热水器,并通过添加石墨纳米颗粒改善相变材料的导热特性,对其储能过程进行调节,可以起到"移峰填谷"的作用.建立了四种不同结构的电热水器三维模型,模拟了电热水器内部速度场与温度场分布特性.考察了进出口水管结构、电加热管布置方式、保温层结构等因素对热水器内部流场及传热特性的影响,研究了不同储能层厚度对电...     

三组元全热耦合精馏过程的模拟计算

本文利用Aspen软件对三组分进料全热耦合精馏的分离流程进行设计和模拟,建立了相应的具体计算步骤。首先利用三塔模型把热耦合精馏过程简化为3个单独的简单清晰分割塔,通过简捷法设计和模拟得到塔板数和回流比等初值后进行严格法模拟,得到热耦合精馏的数据和操作条件。然后采用Aspen软件中的RadFrac模型,将三塔模型的模拟初值代入全热耦合模块进行严格模拟。结果表明,采用全热耦合精馏分离C4三组分比传统精馏的直接序列和间接序列节能约为20%。     

TCS-S热偶精馏过程的优化设计

建立了TCS－S热偶精馏过程优化设计的数学模型，给出非精晰分割精馏塔最小回流比的求解方法，并给出简捷计算和严格计算的求解过程，编制了计算机程序。用苯－甲苯－乙苯物系为例进行考核计算，与普通塔的两个分离序列进行比较，节能效果十分显著。     

面向热集成耦合的精馏过程集成控制与优化

针对具有塔底产品和进料换热热集成的精馏过程,通过机理分析和基于流程模拟软件的仿真分析,说明了再沸热负荷与塔底液位、进料温度等变量的耦合关系,提出了一种面向热集成耦合的集成控制和优化策略,使用再沸热负荷对原料的焓值变化进行补偿,并兼顾塔底液位,保证产品质量合格。集成策略在实际装置上进行了应用研究,解决了塔底产品流量与再沸热负荷之间的协调控制问题。     

Synthesis of complex thermally coupled distillation systems including divided wall columns

The design of thermally coupled distillation sequences explicitly including the possibility of divided wall columns (DWC) is described. A DWC with a single wall can be considered thermodynamically equivalent to a fully thermally coupled (FTC) subsystem formed by three separation tasks (a Petlyuk configuration in the case of three‐component mixtures). It is shown how to systematically identify all the sequences of separation tasks that can produce configurations that include at least a DWC. Feasible sequences that explicitly include DWCs are enforced through a set of logical relationships in terms of Boolean variables. These logical relationships include as feasible alternatives from conventional columns (each column must have a condenser and a reboiler) to FTC systems (only one reboiler and one condenser in the entire system). A comprehensive disjunctive programming formulation for finding the optimal solution is presented. The model is based on the Fenske, Underwood Gilliland equations. However, the disjunctive formulation allows easily the use of any other shortcut, aggregated or even rigorous model without modifying much the structure of the model. Two illustrative examples illustrate the procedure. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1139–1159, 2013     

内部热耦合反应精馏塔塔构型的研究

以乙酸甲酯水解为例,利用模拟软件Aspen Plus建立了内部热耦合反应精馏塔模型,研究了内部热耦合反应精馏塔各种可能塔构型的节能效果,并且在相同的产品要求和最小传热温差下对内部热耦合反应精馏塔各构型的能耗进行了对比。结果表明,塔构型对乙酸甲酯水解的内部热耦合反应精馏流程的操作性能有重要的影响,并且存在最佳构型。其最佳构型的特征为,反应段全部在内部热耦合反应精馏塔的精馏塔内且精馏塔与提馏塔中理论板均参与传热的塔构型。     

乙酰丙酸乙酯的反应精馏模型及隔壁塔节能优化设计

乙酰丙酸乙酯是一种潜在的生物质基平台化合物,在工业上具有很高的应用价值。乙酰丙酸乙酯传统的生产方法主要为间歇反应法,效率较低,产物分离困难且工艺流程较长。因此,本文提出了反应精馏工艺生产乙酰丙酸乙酯,在以中试实验结果为依据的基础上,使用Aspen Plus模拟软件建立了工艺流程,并考察了回流比、进料位置、进料摩尔比以及理论塔板数等关键参数,得到了常规单塔反应精馏工艺生产乙酰丙酸乙酯的最优配置。而后,为了得到纯度大于99.9%的乙酰丙酸乙酯,本文进一步提出了反应精馏双塔精制流程以及反应精馏隔壁塔流程,并通过对两种流程所得到的产品纯度以及能耗的对比,验证了反应精馏隔壁塔工艺生产乙酰丙酸乙酯的有效性以及在节能方面较大的优势。     

乙酸乙烯精馏过程的模拟优化与工业应用

利用化工流程模拟软件对乙酸乙烯精馏过程进行模拟优化,通过模型对比得到了适用于计算该物系的物性方法;分析了各工艺参数对分离过程的影响,得到了最佳进料板位置、回流比和采出量。同时在原有塔体不变的情况下,利用高效导向筛板对乙酸乙烯精馏过程进行改造,并得到了工业应用。改造后工厂的运行结果表明,结合计算机优化的高效精馏技术能有效地提高产品纯度,降低原料和能量消耗,从而取得了很好的经济效益。     

A novel stochastic optimization method to efficiently synthesize large-scale nonsharp distillation systems

This study presents a novel stochastic optimization method for the efficient synthesis of large-scale nonsharp distillation systems, where heat integration and thermal coupling can be involved simultaneously. A new binary tree encoding method was developed to represent distillation sequences with no limits on the number of middle components in nonsharp splits to ensure a complete solution space. Thermally coupled structures were defined by 0–1 binary variables. Evolutionary rules were developed to generate neighboring distillation configurations randomly. Finally, an optimization framework was proposed, where simulated annealing (SA) algorithm was used to optimize distillation configurations; for a certain distillation configuration randomly generated by SA, its continuous variables were optimized using particle swarm optimization algorithm. Four cases—including the synthesis of six- and seven-component nonsharp heat integrated and thermally coupled distillation sequences—were studied to demonstrate that the proposed method was efficient and could obtain optimal and valuable suboptimal solutions with high probabilities.     

物系和分离要求对最优三组元精馏结构选择的影响

针对三组分混合物的分离,选取6种不同分离指数的物系,根据多种进料组成和分离要求,对传统的直接分离序列和间接分离序列及其热集成方式、部分热耦合精馏中的侧线精馏和侧线提馏、完全热耦合结构（即隔板塔）进行了模拟与优化设计,并以年度总费用最低为目标选出各种情况下的最优精馏结构。结果表明,分离指数、进料组成及分离要求都对精馏结构的优化选择都有显著影响,热集成精馏、部分热耦合以及完全热耦合精馏结构分别在不同条件下各具有优势。根据分析结果,对影响最优三组元分离精馏结构的因素进行归纳。     

甲醇精馏工艺及其塔器优化设计

对四塔甲醇精馏节能流程提出了四项优化措施,利用PRO/Ⅱ工艺模拟软件,进行了工况研究.结果表明,采用优化后的工艺流程,甲醇回收率可提高约0.3%,预精馏塔能耗降低约7%;并根据工况研究结果和生产数据,提出了各塔合适的理论级数和操作参数,推荐了各塔结构形式、参考塔径、填料高度或塔盘层数.     

质子交换膜燃料电池混合动力系统能量优化的仿真分析

分析了混合动力系统的控制目标及需要考虑的几个关键参数。以PEMFC混合动力系统为对象,分别针对给定负载模式和实时运行模式进行控制策略设计和能量优化仿真。对给定的负载模式,采用遗传算法对多约束组合优化问题进行求解,仿真结果证明了算法的可行性。对于实时运行模式,在原有模糊控制策略的基础上,引入燃料电池电压和电压变化量对模糊输出进行两级修正。仿真结果表明,改进后的模糊控制策略可以有效提高燃料电池运行效率,降低燃料电池功率波动。     

DMTO装置基于IDA与节能潜力框架的能效分析

为全面分析技术和管理水平、负荷、生产结构、耗能工质等因素对装置能效、节能量和节能潜力的影响, 提出采用IDA指标分解的能源绩效分析和节能潜力分析的综合框架分析DMTO装置的能效。提出的分析框架能综合并且真实有效地反映出能源使用的活动水平、能源结构和能源强度等因素的影响, 并能量化装置的技术与结构对节能量的影响, 因而可以直观地揭示提高能效、降低能耗和节能的有效实施途径。DMTO装置的示例分析, 验证了IDA能效分析与节能潜力分析方法的一致性和实用性, 为提出方法广泛用于能效管理与节能的实践奠定了坚实的应用基础。