Performance and Energy Consumption of Membrane‐Distillation Hybrid Systems for Olefin‐Paraffin Separation

Light olefin and paraffin are commonly separated by energy‐intensive cryogenic distillation. Membrane/distillation hybrid systems constitute an economical alternative separation process. Different configurations of this hybrid system are studied for olefin‐paraffin separation with emphasis on C₃ separation. An approach based on the McCabe‐Thiele method is applied to analyze different process configurations. A facilitated transport membrane is considered as membrane type. Both new column design and augmentation of an existing distillation column by a membrane module are considered. Numerical examples are considered for the separation of propane from propylene through different hybridization shapes with facilitated transport membranes. The energy requirement can be halved using hybrid systems.     

Sugaring‐Out Separation of Acetonitrile from Its Aqueous Solution

The separation of acetonitrile (ACN) from an ACN‐water azeotrope is of particular interest to industrial chemists and process engineers. In the work reported in this article, sugaring‐out, a new phase separation method is reported and used to obtain high purity ACN from an ACN‐water mixture. With the addition of a mono‐sugar (glucose, xylose, arabinose or fructose) or a disaccharide (sucrose or maltose) into an ACN‐water mixture, a phase separation is observed if the sugar concentration exceeds a threshold. The upper phase is rich in ACN while the lower phase is rich in water. The ACN concentration in the upper phase increases when more sugar is added into the ACN‐water mixture. When the glucose concentration is > 35 g/L, the ACN concentration in the upper phase is > 40 %. In the Sudan I extraction test with a glucose‐triggered two‐phase system, an extraction rate of > 80 % is achieved when the glucose concentration is greater than 25 g/L.     

丙酮一步法生产MIBK装置的副产物精馏分离研究

针对丙酮一步法生产MIBK装置的副产物（丙酮、异丙醇、水、MIBK混合物）,采用间歇精馏分离得到纯度〉98％的丙酮、纯度〉99％的异丙醇和水恒沸物、纯度〉90％的MIBK。对分离得到的纯度〉99％的异丙醇和水恒沸物用乙二醇作为萃取剂进行萃取精馏分离得到纯度99．5％异丙醇,同时减压精馏回收乙二醇。     

油页岩干馏油气冷凝回收页岩油的研究

采用间冷回收工艺方法对新疆吉木萨尔油页岩热解干馏油气进行了冷凝回收分析研究,考察了冷凝终温等因素对新疆吉木萨尔油页岩热解干馏油气回收页岩油收率的影响,同时对新疆吉木萨尔油页岩、页岩气和页岩油进行了特征分析,对工业生产具有指导意义。     

Separation of isopropanol from aqueous solution by salting‐out extraction

A novel salting‐out extraction process has been developed to separate isopropanol from aqueous solution. Potassium carbonate was experimentally shown to be effective in modifying the liquid–liquid equilibrium (LLE) of an isopropanol/water/hexane system in favour of the solvent extraction of isopropanol from an aqueous solution with hexane, particularly at suitable salt concentrations. Potassium carbonate enlarged the area of the two‐phase region. This effect essentially increased the distribution coefficient of isopropanol between hexane and water and increased the separation factor for isopropanol vs water, which is an important consideration in designing a solvent extraction process. The effects of potassium carbonate concentration, temperature and pH on the LLE were studied. Finally, a ?30 mm × 1200 mm reciprocating plate column (RPC) was tested to separate isopropanol from an aqueous solution. When isopropanol in an aqueous solution with composition of isopropanol/water = 1:0.95 (wt/wt) was extracted by hexane assisted with 30% (wt%) potassium carbonate aqueous solution, the alcohol–water ratio increased to 11:1 in the extract. © 2001 Society of Chemical Industry     

内压缩流程空分的换热与精馏研究

分析和讨论了内压缩空分设备的氧氮两组分、氧氮氩三组分及氧氩两组分和氮氩两组分的相平衡,精馏部分的上塔、下塔、粗氩塔、精氩塔的精馏以及高压主换热器、低压主换热器、过冷器及主冷凝蒸发器等换热设备。希望能促进空气分离设备在理论方面的发展。     

Separation of ethyl tert-butyl ether-ethanol by combined pervaporation and distillation

A cellulose derivative membrane (30 wt.% cellulose acetate butyrate (CAB) combined with 70 wt.% cellulose acetate propionate (CAP)) was prepared, and its properties were evaluated by the pervaporation separation of mixtures of ethyl tert-butyl ether (ETBE) and ethanol. The experimental results showed that the selectivity and permeability of the membrane were dependent on the blend composition, the processed feed and the experimental temperature. With respect to the temperature, the fluxes obeyed the Arrhenius equation. On the basis of these results, a separation process for the production of ETBE was developed by combining pervaporation and distillation. The distillation column was designed with the software ASPEN PLUS, and the liquid-vapour equilibria were predicted by the UNIFAC method. The area of the membrane was calculated according to the production capacity. It may be concluded that the combined process for the separation of mixtures of ETBE and ethanol is simple with high recovery of the ETBE product.     

Predicting Solubility of Military,Homemade, and Green Explosives in Pure and Saline Water using COSMO‐RS

The conductor‐like screening model for real solvents (COSMO‐RS) has previously been shown to give accurate aqueous solubilities for a range of organic compounds using only quantum chemical simulation data. Application of this method for solid organic explosives, however, faces two difficulties; it requires correction for the free energy of fusion (a generally unknown quantity for these compounds) and it shows considerable error for common explosive classes such as nitramines. Herein we introduce a correction factor for COSMO‐RS that is applicable to a wide range of explosives, and requires no data beyond a quantum chemistry calculation. This modification allows COSMO‐RS to be used as a predictive tool for new proposed explosives or for systems lacking experimental data. We use this method to predict the temperature‐dependent solubility of solid explosives in pure and saline water to an average accuracy of approximately 0.25 log units at ambient temperature. Setschenow (salting‐out) coefficients predicted by this method show considerable improvement over previous COSMO‐RS results, but are still slightly overestimated compared to the limited experimental data available. We apply this method to a range of military, homemade, and “green” explosives that lack experimental seawater solubility data, an important property for environmental fate and transport modeling.     

Experimental Investigations of Three‐Phase Distillation in a Packed Column

An experimental study with three different heterogeneous azeotropic mixtures (acetone/toluene/water, 1‐propanol/1‐butanol/water and ethanol/cyclohexane/water) has been carried out with the object to analyze the separation efficiency of three‐phase distillation in a packed column. The experiments were made under total reflux in a 70 mm column packed with Sulzer Optiflow C.36. The results show the influence of the second liquid phase on the mass transfer and with that on the separation efficiency in a packed column.     

合成氨弛放气膜分离氢回收与氨蒸馏的集成应用

合成氨弛放气中含有价值较高的氢气与氨气,传统的处理方法是将弛放气回收氨气后送燃烧系统,造成了氢气的极大浪费.将膜分离氢回收与氨蒸馏集成一个系统,在回收氢气的同时回收氨,使膜分离技术具有更强的兼容性和灵活性,从投资与回报方面分析也能体现出此集成方法的经济性与合理性.     

Offset‐Free Inferential Feedback Control of Distillation Compositions Based on PCR and PLS Models

An offset‐free inferential feedback control strategy for distillation composition control using principal component regression (PCR) and partial least squares (PLS) models is presented in this paper. PCR and PLS model based software sensors are developed from process operational data so that the top and bottom product compositions can be estimated from multiple tray temperature measurements. The PCR and PLS software sensors are then used in the feedback control of the top and bottom product compositions. With this strategy the problem of substantial time delay in composition analyzer based control and of substantial bias in single tray temperature control can be overcome. A practically very important issue in software sensor based feedback control is that static control offsets often exist due to a static estimation bias, especially when the process operating condition changes. A technique for eliminating the static estimation bias and the resulting static control offsets through mean updating of process measurements is proposed in this paper. Applications to a simulated methanol‐water separation column demonstrate the effectiveness of this control strategy.     

Salting‐out of acetone, 1‐butanol,and ethanol from dilute aqueous solutions

The salting‐out phase equilibria for acetone, 1‐butanol, and ethanol (ABE) from dilute aqueous solutions using potassium carbonate (K₂CO₃) and dipotassium hydrogen phosphate trihydrate (K₂HPO₄?3H₂O) as outstanding salting‐out agents were investigated. Increasing the salt concentration strengthened the salting‐out effects and improved the distribution coefficients of all three solvents (ABE) significantly. Temperature had a slight effect on the phase equilibria. The K₂HPO₄ solution (69 wt %) showed a stronger salting‐out effect than the K₂CO₃ solution (56 wt %) on recovering ABE from dilute aqueous solutions. Dilute aqueous solutions containing more solvents increased the recoveries of acetone and 1‐butanol, while the results showed a negligible effect on the solubility of ABE. The solubility of ABE was also correlated well with the molar number of salt per gram of water in the aqueous phase. A new equation demonstrated this satisfactorily. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3470–3478, 2015     

Separation of Tc‐99m by means of radiation‐grafted membranes

The characterization and possibility of the practical use of different polymeric materials for the purpose of radioactive isotope separation from their wastes were studied. The influence of chemical treatment on the chelation or adsorption capacity at 25 °C was investigated. The equilibrium swelling of these polymers in distilled water at room temperature and the effect of solvent composition on the graft yield were also explored. In this study, the mechanical, chemical resistance and other properties for the grafted, untreated, and treated membranes were investigated. The performance of the membranes was studied as a function of time and degree of grafting. The effects of chemical treatment on the initial activity and separation of Tc‐99m have also been examined. The base polymer and degree of grafting have great influence on the Tc uptake. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1207–1215, 2001     

Design and Numerical Simulation Analysis of an Integrative Gas‐Liquid‐Solid Separation Hydrocyclone

Normally, a gas‐liquid‐solid separation includes both degassing and desanding processes, which means a relatively higher facility investment and larger energy consumption. Based on an inner‐cone hydrocyclone developed before, an integrative degassing and desanding hydrocyclone was designed. Its design idea and process are described in detail. By means of a hollow inner cone (IC), the separated liquid enters into the cone through holes on it and then flows to the liquid‐phase outlet. Due to integrative separation and tangential solid outlet, the separator has a more compact size. Simulation analysis of the effect of IC diameter and IC height on separation performance was carried out. Results indicate that with a larger IC diameter the gas content in the solid outlet decreases, while as the IC height rises, the gas content in the liquid outlet increases.     

热敏物料间歇精馏过程

热敏物料是受热会发生化学反应产生杂质的物料,广泛存在于化学工业生产中,其分离提纯比较困难.间歇精馏过程是分离热敏性物料的一种重要方法.本文介绍了热敏物料受热险度和热稳定性指数概念以及热敏物料精馏设备的评价方法.综述了热敏物料间歇精馏工艺及设备的研究进展,如:冷存料循环釜式热敏物料间歇精馏、带有动态侧线出料的热敏物料间歇...