共查询到19条相似文献,搜索用时 81 毫秒
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对间歇萃取精馏分离技术和进展进行了评述,主要从萃取精馏溶剂选择,操作方式,新型塔设备的研究,操作优化及过程模拟等几个方面,介绍了国内外关于间歇萃取精馏新兴分离技术的最新研究动态,最后指出了萃取精馏技术目前存在的问题和今后发展的方向。 相似文献
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提出了带塔底储罐的间歇萃取精馏操作方式.新操作方式使精馏过程中加入的溶剂及塔内回流液直接流入塔底储罐,不再返回塔釜.以乙二醇为溶剂分离乙醇–水共沸物的实验研究表明,新操作方式克服了普通间歇萃取精馏塔釜体积庞大的缺陷,同时具有塔釜温度稳定、加热容易控制、收率提高等优点. 相似文献
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1引言
间歇精馏以其操作灵活、投资少并适合分离热敏性物料等特点而被广泛应用于现代化工生产。萃取精馏是一种常用的特殊精馏方法,通过加入高沸点的第三组分(萃取剂)来改变原混合物的相对挥发度而使共沸物或近沸点物系分离。20世纪80年代Berg提出了间歇萃取精馏操作方式,它同时具备了间歇精馏的灵活性、经济性与萃取精馏的实用性,特别适用于化工、制药、石油深加工等行业中普通精馏无法完成的相对挥发度小的物系的分离,兼有学术研究和实际应用价值。 相似文献
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提出了伴有简单蒸馏的间歇萃取精馏操作方式。在新操作方式中,混有溶剂的塔内液相不流回塔釜,而是流入塔底简单蒸馏釜,再经简单蒸馏的汽相返回塔釜,而富含溶剂的液相留在简单蒸馏釜中。以乙二醇作溶剂分离乙醇-水物系统为例的实验研究表明:新的操作方式具有塔釜温度稳定、溶剂回收简便、操作时间短和操作弹性大等优点。 相似文献
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Batch extractive distillation (BED) is a special method used in the distillation process by adding a solvent into the batch distillation column to alter the relative volatility of the components and improve the separation. A comprehensive design and simulation method is required due to the complexity of BED. In this study, a quasi-steady-state model for BED is proposed, the derivation and solution of the model are presented. This shortcut model can be used to simulate the composition and temperature of the reboiler, the top and other plates of the column in a batch extractive distillation operation. The calculated values are in good agreement with the experi-mental data. The results show that the quasi-steady-state model is a practical method because of some advantages such as high precision and fast calculation. 相似文献
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Extractive distillation(ED) is one of the most promising approaches for the separation of the azeotropic or closeboiling mixtures in the chemical industry. The purpose of this paper is to provide a broad overview of the recent development of key aspects in the ED process involving conceptual design, solvent selection, and separation strategies. To obtain the minimum entrainer feed flow rate and reflux ratio for the ED process, the conceptual design of azeotropic mixture separation based on a topological analysis via thermodynamic feasibility insights involving residue curve maps, univolatility lines, and unidistribution curves is presented. The method is applicable to arbitrary multicomponent mixtures and allows direct screening of design alternatives. The determination of a suitable solvent is one of the key steps to ensure an effective and economical ED process. Candidate entrainers can be obtained from heuristics or literature studies while computer aided molecular design(CAMD) has superiority in efficiency and reliability. To achieve optimized extractive distillation systems, a brief review of evaluation method for both entrainer design and selection through CAMD is presented. Extractive distillation can be operated either in continuous extractive distillation(CED) or batch extractive distillation(BED), and both modes have been well-studied depending on the advantages in flexibility and low capital costs. To improve the energy efficiency, several configurations and technological alternatives can be used for both CED and BED depending on strategies and main azeotropic feeds. The challenge and chance of the further ED development involving screening the best potential solvents and exploring the energy-intensive separation strategies are discussed aiming at promoting the industrial application of this environmentally friendly separation technique. 相似文献
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Diester manufacturing plants produce large quantities of glycerol solutions. Their economic development requiressodium sulfate elimination to obtain glycerol rates over 80% of the initial content. Conventional electrodialysis (ED) and bipolar electrodialysis (BED) were investigated for their performances in the demineralisation of effluents. Results indicate that both ED and BED achieve the demineralisation objective with a global loss below 2.5% of the initial glycerol. Salt fluxes are twice as high with a bipolar membrane, bipolar membranes having however a lower efficiency. Hence energetic consumption is higher for BED. This technique also leads to the production of alkali and acid solutions which are useful to the diester process. The glycerol content of the solutions acts, via its viscosity, on the energetic cost of fluid pumping and on energetic efficiency. Therefore, ED or BED has to be used before the preconcentration of the solution. 相似文献
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William L. Luyben 《化学工程与技术》2017,40(10):1895-1906
The binary mixture of n‐heptane and isobutanol forms an azeotrope at atmospheric pressure, with a composition of 66.9 mol % n‐heptane and a temperature of 364 K. Several methods of separation are possible. This study compares the steady‐state economics and the dynamic controllability of three alternative separation techniques: a two‐column extractive distillation process, a two‐column pressure‐swing distillation process, and a single column with a refrigerated condenser. 相似文献
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Continuous homogenous azeotropic distillation (CHAD) and pressure-swing distillation (PSD) are explored to separate a minimum-boiling azeotropic system of ethyl acetate and n-hexane. The CHAD process with acetone as the entrainer and the PSD process with the pressures of 0.1 MPa and 0.6 MPa in two columns are designed and simulated by Aspen Plus. The operating conditions of the two processes are optimized via a sequential modular approach to obtain the minimum total annual cost (TAC). The computational results show that the partially heat integrated pressure-swing distillation (HIPSD) has reduced in the energy cost and TAC by 40.79% and 35.94%, respectively, than the conventional PSD, and has more greatly reduced the energy cost and TAC by 62.61% and 49.26% respectively compared with the CHAD process. The comparison of CHAD process and partially HIPSD process illustrates that the partially HIPSD has more advantages in averting the product pollution, energy saving, and economy. 相似文献
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San-Jang Wang Hsiao-Ping Huang 《Chemical Engineering and Processing: Process Intensification》2011,50(7):709-717
An innovative entrainer-enhanced reactive distillation (RD) process is presented, which aims to the production of high-purity butyl cellosolve acetate from butyl cellosolve and acetic acid via an esterification reaction. This entrainer-enhanced RD process can procure technical advantages from both heterogeneous azeotropic distillation and RD. Solvents such as cyclohexane, ethylene dichloride, toluene, and octane are considered as candidates in this esterification RD process. The function of entrainers is to simplify the separation between water and acetic acid. For this purpose, the proper entrainer to use is thus evaluated based on its mutual solubility with water in two liquid phases. Simulation results reveal that total annual cost can be substantially reduced when cyclohexane, toluene, and octane are used as entrainers in the RD column. The octane-enhanced RD provides the most economical design in this studied case. 相似文献