节能减排,永恒的主题——《现代蒸馏技术》读后感

《现代蒸馏技术》一书,已于2009年3月由化学工业出版社出版,该书由天津大学教授兼精馏技术国家研究中心主任李鑫钢主编。天津大学精馏技术国家工程研究中心久负盛名,有多年的研究成果和设计经验。他们经过总结归纳,精心组织编著了此书。该书条理清晰,内容系统、全面,资料翔实,偏重于工程化技术、节能与强化技术和塔器大型化技术,并有蒸馏过程常见问题诊断与设计实例,涵盖了国内外蒸馏技术的发展历史和最新研究动态,既有系统的理论分析,又有实际的工程应用,是化学工程领域关于蒸馏技术的一部较系统的专著。     

精馏技术研究进展与工业应用

精馏是化学工业中应用最广泛的关键共性技术,广泛应用于石油、化工、化肥、制药、环境保护等行业。精馏具有应用广泛、技术成熟等优点,但存在设备投资大、分离能耗高等问题,因此研究开发新型高效传质元件、开发新型节能精馏技术,具有重要的社会意义和经济价值。本文从精馏塔类型、流体力学性能、传质性能、塔器大型化、过程节能、过程强化等方面,介绍了精馏技术的研究进展与工业应用。对于板式塔,从气液两相流动状态、压降、漏液和雾沫夹带方面研究了塔板的流体力学性能;对于填料塔,从压降、液泛和持液量方面研究了填料塔的流体力学性能,但目前的研究仍以经验关联式为主,缺乏严谨的的理论模型。对于气液两相的传质性能研究,简述了气液两相传质理论,但科学、精准的传质模型尚未提出。对于塔器大型化的应用研究,介绍了塔板、气液分布器和支撑装置等大型化关键技术的工业应用。从精馏过程典型节能技术、耦合节能技术、流程节能技术、低温余热回收和特殊精馏等方面,介绍了精馏过程节能与强化的应用进展。文章最后对精馏过程的传质、强化和集成进行了展望。     

精馏过程大型化集成技术

精馏是重要的化工分离单元操作过程。现代精馏技术要求通过关键设备的大型化实现规模效应。本文介绍了天津大学针对塔器大型化存在的液面梯度、流体分布、大型内构件的变形和长周期运行等问题,采用计算流体力学、力学分析和过程模拟与分析技术,进行了塔器大型化方面的理论和技术研究,形成多项大型化关键技术,并在千万吨级炼油和百万吨级乙烯等项目上成功应用,取得了良好经济和社会效益。本文还结合工业实例,介绍了塔器大型化关键技术及其应用。     

焦炉煤气精制工艺大型化的挑战和方向

煤气精制大型化是配套焦炉大型化的必然趋势,也是完成国家节能减排目标的必然要求。结合某大型钢铁联合企业正在规划的炼焦项目,精制工艺采用磷酸吸收无水氨和真空碳酸盐工艺为例,从煤气精制大型化优势、大型化关键技术和技术可行性等几个方面对目前国内煤气精制工艺大型化的思路和方向进行了系统分析。     

差压热耦合蒸馏节能技术

开发了一种广泛适用于蒸馏分离过程的新型差压热耦合蒸馏技术,该技术将精馏塔分割为两个压力不同的塔,利用高压塔顶蒸汽作为低压塔底的热源,实现热能的耦合匹配,达到蒸馏过程大幅度节能的目的。利用计算机模拟方法对该技术应用在丙烯-丙烷分离和混合C4分离过程中的节能效果进行了计算和分析,结果表明与现有常规蒸馏过程相比,差压热耦合低能耗蒸馏过程能耗可以分别降低92.3%和87.1%,节能效果显著。     

蒸馏过程强化技术研究进展

蒸馏过程强化技术作为我国现代化学工业发展的重要研究领域,是过程强化概念在化学工业成功应用的典范之一。随着近些年的发展,蒸馏过程强化技术的研究已形成了一套较完整的体系,但也出现了一系列新的难题与挑战。为此,本文针对混合物相对挥发度与气液传质两个蒸馏过程强化的基础理论本质问题,以基础理论创新、关键技术突破和关键装备研究进展为主线,从强化原理、研究进展、工业应用及发展3方面系统介绍共沸蒸馏、萃取蒸馏、反应蒸馏这3类典型的引入质量分离剂强化的蒸馏过程及其耦合技术;微波、超重力场等典型外场作用下的引入能量分离剂强化的蒸馏过程,并系统介绍以新型塔内件及新型塔结构为切入点的基于先进设备强化的蒸馏过程,为迎接这一领域新的难题和挑战提供新思路。     

蒸馏节能技术进展

从提高蒸馏塔能效,建立蒸馏复合系统,开发新的替代技术等方面介绍了工业蒸馏过程中节能技术进展。     

离心分离设备技术现状与发展趋势

简要回顾了离心分离设备发展简况和行业现状,重点围绕离心分离系统、特殊专用机型研发、分离过程强化、结构优化和驱动与节能等方面论述了国外离心分离设备的技术现状,最后指出离心分离设备技术发展趋势是高效、节能、专机、大型化。     

加压蒸馏用于乙醛生产节能

将加压蒸馏技术应用于乙醛生产，节能效果显著。本文简要介绍了加压操作对乙醛蒸馏过程的影响及其产生的节能效果和适宜操作条件的选择。     

天津大学传质理论与蒸馏技术研究

介绍了天津大学在蒸馏传质理论方面取得的研究成果,总结蒸馏过程模拟计算的三种混合模型--平衡级全混合模型、非平衡级全混合模型、非平衡级部分混合模型.论述了蒸馏过程的传质动力学,提出分形理论在界面传递扩散研究方面可能会取得较大进展,非平衡热力学、耗散结构理论和协同论对描述系统动力学演化和非线性传递过程规律可能起到较大的推动作用.概括了板式塔和填料塔的特点,列举了一些天津大学推广新型填料塔技术的成功范例.总结了当前新蒸馏技术添加物精馏、反应精馏、催化精馏、吸附蒸馏、膜蒸馏、分子蒸馏和动态精馏新型蒸馏技术的基本原理、特点以及天津大学在这些方面的最新进展.最后展望了蒸馏工程学科的发展方向蒸馏学科正由传统的依靠经验、半经验过渡到凭半理论以至理论,蒸馏过程正由传统的单一分离过程过渡到耦合和复杂的优化分离过程以提高分离效率和节能,蒸馏设备正以高效、节能的新一代更新、淘汰传统的一代.     

基于自适应并行禁忌搜索的精馏分离序列优化综合

由于精馏分离序列与二叉树之间具有同构性,在数据结构上精馏分离序列可以抽象为二叉树.采用图论方法建立了二叉树相邻切分点变换机制,进而形成有效的邻域结构.将自适应机制和并行技术引入禁忌搜索算法中,根据记忆频率信息自适应调整禁忌长度与候选集规模,通过搜索任务分配安排形成多任务并行处理.数值实验表明自适应并行禁忌搜索算法能够成功解算大规模精馏分离序列优化综合问题.     

国内三氯氢硅精馏节能技术应用进展

综述了系统耦合节能技术在国内三氯氢硅精馏工艺中的应用现状。介绍和分析了多效精馏、热泵精馏、热耦合精馏、差压耦合精馏及其有机结合在三氯氢硅精馏节能降耗方面的应用现状。讨论了三氯氢硅精馏节能技术的发展趋势,并指出系统耦合节能技术的大力实施是我国多晶硅行业追赶国际先进水平的有效途径。     

Conceptual process design of extractive distillation processes for ethylbenzene/styrene separation

In the current styrene production process the distillation of the close-boiling ethylbenzene/styrene mixture to obtain an ethylbenzene impurity level of 100 ppm in styrene accounts for 75–80% of the energy requirements. The future target is to reach a level of 1–10 ppm, which will increase the energy requirements for the distillation even further. Extractive distillation is a well-known technology to separate close-boiling mixtures up to high purities. The objective of this study was to investigate whether extractive distillation using ionic liquids (ILs) is a promising alternative to obtain high purity styrene. Three ILs were studied: [3-mebupy][B(CN)₄], [4-mebupy][BF₄], and [EMIM][SCN]. Extractive distillation with sulfolane and the current conventional distillation process were used as benchmark processes. The IL [4-mebupy][BF₄] is expected to outperform the other two ILs with up to 11.5% lower energy requirements. The operational expenditures of the [4-mebupy][BF₄] process are found to be 43.2% lower than the current distillation process and 5% lower than extractive distillation with sulfolane extractive distillations. However, the capital expenditures for the sulfolane process will be about 23% lower than those for the [4-mebupy][BF₄] process. Finally, the conclusion can be drawn from the total annual costs that all studied extractive distillation processes outperform the current distillation process to obtain high purity styrene, but that the ILs evaluated will not perform better than sulfolane.     

气液液三相精馏流体力学性能研究进展

介绍了气液液三相精馏塔板流体力学性能研究的进展情况,讨论了塔板上流动工况、塔板上两液相的混合状况及影响流体力学性能的有关因素。文中提到的许多观点和建议对于优化精馏塔的设计至关重要。     

旋转填料床精馏过程流体力学性能研究

在对旋转填料床精馏特性研究的基础上,以塑料多孔板为填料,乙醇-水为体系,在全回流操作条件下,进一步研究了气相动能因子F、超重力因子β和回流量L对旋转填料床流体力学特性的影响,证明了旋转填料床的低耗能特性。     

Distillation technology – still young and full of breakthrough opportunities

Throughout history, distillation has been the most widespread separation method. However, despite its simplicity and flexibility, distillation still remains very energy inefficient. Novel distillation concepts based on process intensification, can deliver major benefits, not just in terms of significantly lower energy use, but also in reducing capital investment and improving eco‐efficiency. While very likely to remain the separation technology of choice for the next decades, there is no doubt that distillation technology needs to make radical changes in order to meet the demands of the energy‐conscious modern society. This article aims to show that in spite of its long age, distillation technology is still young and full of breakthrough opportunities. Moreover, it provides a broad overview of the recent developments in distillation based on process intensification principles, for example heat pump assisted distillation (e.g. vapor compression or compression–resorption), heat‐integrated distillation column, membrane distillation, HiGee distillation, cyclic distillation, thermally coupled distillation systems (Petlyuk), dividing‐wall column, and reactive distillation. These developments as well as the future perspectives of distillation are discussed in the context of changes towards a more energy efficient and sustainable chemical process industry. Several key examples are also included to illustrate the astonishing potential of these new distillation concepts to significantly reduce the capital and operating cost at industrial scale. © 2013 Society of Chemical Industry     

应用遗传算法实现精馏分离序列优化综合

阐述了采用遗传算法求解具有组合爆炸特征的精馏分离序列综合问题。首先在数据结构上将精馏分离序列抽象为二叉树结构编码,然后应用图论方法建立起有效的交叉和变异算子,最后对10组分精馏分离序列综合问题实例进行求解。结果表明,遗传算法对最优解命中率达80％,平均空间搜索率仅为0．0318。因此遗传算法能够成功解算大规模精馏分离序列优化综合问题。     

大型甲醇精馏装置无废水排放模拟研究

随着国内甲醇装置大型化发展,甲醇生产生的废水量越来越大,给环保带来了更大的压力;目前甲醇精馏废水处理技术还不十分完善。利用PROⅡ化工模拟软件对甲醇精馏进行节能、节水模拟研究,模拟过程中利用常压塔的废水代替加压塔脱盐水补水,精馏过程无废水外排,减少了环境污染、为节水增效提供了一条新的途径。     

Soft-sensing modeling and intelligent optimal control strategy for distillation yield rate of atmospheric distillation oil refining process

It is a challenge to conserve energy for the large-scale petrochemical enterprises due to complex production process and energy diversification. As critical energy consumption equipment of atmospheric distillation oil refining process, the atmospheric distillation column is paid more attention to save energy. In this paper, the optimal problem of energy utilization efficiency of the atmospheric distillation column is solved by defining a new energy efficiency indicator — the distillation yield rate of unit energy consumption from the perspective of material flow and energy flow, and a soft-sensing model for this new energy efficiency indicator with respect to the multiple working conditions and intelligent optimizing control strategy are suggested for both increasing distillation yield and decreasing energy consumption in oil refining process. It is found that the energy utilization efficiency level of the atmospheric distillation column depends closely on the typical working conditions of the oil refining process, which result by changing the outlet temperature, the overhead temperature, and the bottom liquid level of the atmospheric pressure tower. The fuzzy C-means algorithm is used to classify the typical operation conditions of atmospheric distillation in oil refining process. Furthermore, the LSSVM method optimized with the improved particle swarm optimization is used to model the distillation rate of unit energy consumption. Then online optimization of oil refining process is realized by optimizing the outlet temperature, the overhead temperature with IPSO again. Simulation comparative analyses are made by empirical data to verify the effectiveness of the proposed solution.