NOVEL ENERGY-SAVING METHOD OF RECTIFICATION

The conventional rectification method to separate and purify chemical mixtures has the disadvantage of being an energy-intensive unit operation. The innovative method proposed in this article employs vapor and liquid recycles to the trays that in turn reduce the reflux rate and vapor boil-up rate, resulting in energy reduction without compromising the separations.

These findings were supported with examples of ethanol-water and butane- pentane system separations. With ethanol-water system, the experiments were conducted without overhead liquid recycle and using 16 and 5 vapor recycles. The energy saved was found to be 25-35% for 16 recycles and 20-30% for 5 recycles. Butane-pentane system was chosen as an example of industrial use of the proposed method. A liquid overhead reflux ratio of 0.5 (L/D) was used with vapor recycles, compared to a reflux ratio of 1.25 for the conventional separation without vapor recycles. This resulted in 30-35% saving in energy while giving the same productivity of the column. Butane-pentane separation was also simulated using a commercial process simulator (ASPEN^©PLUS).     

Mechanism analysis of solvent selectivity and energy-saving optimization in vapor recompression-assisted extractive distillation for separation of binary azeotrope

Octane and p-xylene are common components in crude gasoline, so their separation process is very important in petroleum industry. The azeotrope and near azeotrope are often separated by extractive distillation in industry, which can realize the recovery and utilization of resources. In this work, the vapor–liquid equilibrium experiment was used to obtain the vapor–liquid equilibrium properties of the difficult separation system, and on this basis, the solvent extraction mechanism was studied. The mechanism of solvent separation plays a guiding role in selecting suitable solvents for industrial separation. The interaction energy, bond length and charge density distribution of p-xylene with solvent are calculated by quantum chemistry method. The quantum chemistry calculation results and experiment results showed that N-formylmorpholine is the best solvent among the alternative solvents in the work. This work provides an effective and complete solvent screening process from phase equilibrium experiments to quantum chemical calculation. An extractive distillation simulation process with N-formylmorpholine as solvent is designed to separate octane and p-xylene. In addition, the feasibility and effectiveness of the intensified vapor recompression assisted extraction distillation are also discussed. In the extractive distillation process, the vapor recompression-assisted extraction distillation process is globally optimal. Compared with basic process, the total annual cost can be reduced by 43.2%. This study provides theoretical guidance for extractive distillation separation technology and solvent selection.     

醋酸生产精馏装置改造的研究

吉化电石厂的醋酸生产目前仍采用乙醛氧化法制取醋酸的工艺技术,精馏工艺采用的流程为高低高的双塔精馏方式。鉴于此,本研究采用的工艺为单塔精馏,减小物料在精馏过程中的停留时间,以达到节能,省时,减少费用的目的,避免双塔精馏所造成的设备与能源的浪费。     

PREPARATION OF ULTRAPURE PIVALIC ACID BY RECTIFICATION

A rectification method was developed for the purification of pivalic acid (PVA) on an experimental scale. Ultrapure PVA with a purity of 99.993% was prepared at a rate of 250 mL a week by multistep rectifications, a more convenient and much faster method than the traditional zone refining method. Typical operational conditions were: head pressure around 1 kPa, reboiler temperature 85°C, head vapor temperature 55°C, condenser temperature 36.5°C, and reflux ratio of 6:1. A formula was given to determine the purity of PVA based on the relationship of freezing point and purity. The freezing point of ultrapure PVA, which was obtained by measuring solidification temperature curve using an inner sheath method, is 35.912 ± 0.001°C.     

茂名石化乙苯/苯乙烯精馏塔的改造

茂名石化采用新型高效脉冲规整填料成功对原板波纹填料乙苯/苯乙烯精馏塔进行了改造,取得了很好的效果,塔顶苯乙烯质量分数由原来的5%降至1%以下,苯乙烯质量分数达到99.9%以上,乙苯质量分数小于500×10-6。     

COMPUTER EVALUATION OF PARASTILLATION PROCESS

A mathematical model and an iterative method is developed for simulating parastillation processes, where the uprising vapour stream is divided into two equal parts at the bottom of the distillation column and the whole amount of the falling liquid is stage-by-stage alterantively contacted with both parts of the vapour. According to our parametric study and simulated industrial examples this arrangement increases the number of theoretical stages per unit height of column, ensures lower column pressure drop and provides considerable energy savings for the same separation, when compared to a conventional column. The advantages especially at low pressures seem to be promising.     

浅谈整流机组的均流及其检测与调整

分析了对整流机组均流程度进行检测与调整的必要性。介绍了衡量均流程度的均流系数K及其计算方法,提出了简便易行且安全可靠的快熔元件压降检测调整法。     

Investigation on and industrial application of degrading of methanol feed in methanol to propylene process

At present, methanol to propylene (MTP) technology developed by Lurgi Company is adopted for commercial plants and refined methanol with the purity ≥ 99.85 wt% is required as the feed of MTP unit in Lurgi's technology. Therefore, high energy cost for refined methanol production is one of the bottlenecks to improve the economy of MTP technology. Reducing the grade of feed refined methanol may be an effective method to save energy and reduce operation costs in MTP process. In this work, experiments and process simulation were carried out to investigate the influence and feasibility of degrading the methanol feed. Experiments were conducted to investigate the influence of crude methanol feed on conversion and selectivity of MTP reaction as well as the performance of ZSM-5 catalyst. The experimental results showed that degrading the methanol feed had no obvious influence on the conversion and selectivity of MTP reactions and the catalyst deactivation was caused by the carbon accumulation and metals deposition on the active sites. The process simulation results showed that the influence on the conversion and selectivity as well as the stream load of MTP process was negligible if 98mol% methanol was used as feed. Finally, industrial experiments were conducted by adjusting the operation parameters to degrade of feed methanol of the commercial 500 kt·a^-1 MTP unit of Ningmei Group in China. The results of industrial application illustrated that annually 180 kt fuel coal and 150 kt desalted water as well as1770 MW·h^-1 electricity would be saved when the water content increased from 0.01% to 0.4%. This work has identified the feasibility to improve MTP technology by degrading the methanol feed.     

顺流双效HGL精馏过程模拟与优化设计

针对顺流双效HGL精馏过程进行了具体研究,建立了最优化设计数学模型并编制了通用计算机程序,用实例对所建立的数学模型及优化设计方法和节能效果进行考核。提出了简捷优化法与逐板严格计算优化相结合的方法,克服了以往优化设计计算中仅求得局部最优解的弊端。     

ON THE EXERGY ANALYSIS OF BINARY DISTILLATION COLUMNS WITH HEAT INTEGRATION

The exergy analysis is done for the conventional distillation, the VR (Vapor Recompression) distillation, and the SRV (Secondary Reflux and Vaporization) distillation with the aid of computer simulation. It is shown that the careful use of thermodynamic diagrams helps us for the exergy analysis.     

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。     

喷雾干燥节能技术研究

通过从喷雾干燥所涉及的操作工艺参数和喷雾干燥工艺流程调整等方面进行探索 ,深入研究了影响喷雾干燥能耗的主要因素和相应的结果 ,并提出了针对性的解决喷雾干燥能耗高的方法 ,使得采用喷雾干燥达到理想的效果     

燃气抽屉窑炉的节能分析

本文就燃气抽屉窑炉的各个方面进行了节能降耗分析与探讨，为进一步加强燃气抽屉窑炉的能耗管理提供帮助。     

Designing four-product dividing wall columns for separation of a multicomponent aromatics mixture

Preliminary evaluations using a simple but reliable short-cut method indicated that a 15 component aromatics mixture can be separated very efficiently into four fractions according to the given product specifications employing either a single or a multiple partition wall dividing wall column (DWC). The obtained results have been used to initiate rigorous simulations, to determine the number of stages required in different sections, as well as to obtain internal flows of vapour and liquid necessary for dimensioning and adequate cost estimation for two design alternatives. Based on the comparison of total annualised costs it appears that a multi-partition wall configuration that maximizes energy efficiency is a more attractive option for implementation in aromatics processing plants than more practical single partition wall configuration.     

合同能源管理在陶瓷产业节能减排领域的发展前景

描述了合同能源管理模式的特点,从陶瓷生产耗能排放现状、产业转型升级和可持续发展出发,分析了将合同能源管理运用于陶瓷产业节能减排领域及发展前景。     

EXPERIMENTAL STUDIES ON A NOVEL CHEMICAL HEAT PUMP DRYER USING A GAS-SOLID REACTION

The authors have been studying Chemical Heat Pumps (CHP) from the viewpoints of energy saving and environmental impact. The CHP can store thermal energy in the form of chemical energy by an endothermic reaction, and release it at various temperature levels during heat demand periods by exo/endothermic reactions. The authors have proposed in an earlier study a novel chemical heat pump (CHP) system for environmentally-friendly effective utilization of thermal energy in drying as a chemical heat pump dryer (CHPD). In this exploratory study, we test the effectiveness of operating the proposed CHPDs experimentally. Basic experiments on the CHPDs such as hot dry air production for convective drying are performed on lab-scale CHPD apparatuses using gas-solid reactions in calcium oxide/calcium hydroxide reactant beds. The proposed CHPDs are found to produce hot air by CHP operation for drying. The temperature levels of the produced hot air and the reaction rates/conversions are as good as in the case of hot water supply system using basically same CHP operation. The cold heat for air dehumidification is also found to be generated/recovered by the same CHPD system. The generated heat amounts can be increased by changing the operating conditions although the heat recovery must be enhanced for practical application of CHPDs.     

日用陶瓷的低碳制备技术

全球气候变暖已成为当今世界最为严峻的问题之一,如何有效地防止温室气体的排放也是世界各国必须面临的严峻挑战。对于高能耗、二氧化碳排放量较大的陶瓷行业来说,实现陶瓷的低碳生产,是提高企业竞争力的一条重要途径。     

DISTILLATION COLUMN DESIGN BY METHOD OF McCABE AND THIELE: DISTMAN COMPUTER GRAPHICS PROGRAM

A computer graphics program developed for the IBM PC calculates equilibrium and operating lines and steps off the number of stages on screen using the McCabe-Thiele method. The results are obtained by graphics, not by numerical methods, so that the accuracy depends upon the screen resolution or pixel density. The equilibrium line is drawn from bubble-point temperature calculations using constants from the Wilson and Antoine equations. The operating lines and staircase are constructed by computer graphics according to the prescribed operating parameters. Design variables, which include the reflux ratio, quality of feed, Murphree efficiency, product purities and pressure, may be changed interactively.     

二段炉加过量空气节能方案研究与分析

二段炉加过量空气，一段炉转化负荷相应降低，可节省一段炉燃气用量，提高转化系统的有效能利用率，达到节能的效果，在低负荷下增加二段炉的过量空气，增产节能效果更为明显，加过量空气后工艺参数作适当的调整，生产装置可以稳定运行。     

挖掘玻纤池窑生产中的节能潜力

分析长风厂2005年冷修技改后,在池窑节电工作中所作的探索与实践,通过对中碱玻纤池窑通路电熔部分节电潜力的挖掘,取得了明显的经济和社会效益。与从事玻纤生产的同行进行技术交流,在企业节能方面探索出更好的方法和途径,进一步降低生产成本,提高经济效益。