氢同位素的低温精馏分离及模拟技术

低温精馏分离氢同位素的技术,是可使聚变反应器燃料循环使用的有效方法。在研究低温精馏氢同位素的过程中,必须考虑到物系的特殊性,如氚具有衰变热、氢溶液的非理想性,以及严格的分离要求等。文章从理论及实际出发综述了氢同位素低温精馏体系的发展过程,并比较和讨论了各种流程的构造及特点,总结了氢同位素低温精馏模拟研究的发展历程和目前状况。提出进一步研究低温精馏分离氢同位素的必要性。     

A Novel Procedure of Hydrogen Isotope Separation Based on Chemical Exchange and a Selective Permeable Membrane

Abstract

It is shown theoretically that a novel process of hydrogen isotope separation can be obtained by combining bithermal isotopic exchange with transport through a selective permeable membrane. The theory of the process predicts that a small column with high separation and very small inventory can be realized. The method is attractive especially for small and medium scale processes, such as tritium enrichment, heavy water upgrading, and final deuterium concentration.     

焦化蒸氨废水余热回收利用新技术开发与应用

针对传统焦化蒸氨废水工艺余热未全面回收利用的问题,设计开发了蒸氨废水余热回收利用新技术。通过蒸汽、热水两用型制冷、采暖双工况吸收式热泵机组,可夏季回收蒸氨废水余热制取热水,作为制冷机驱动热源制取工艺冷却水,满足煤气净化回收系统冷却需要,冬季回收蒸氨废水余热并辅以蒸汽为热源生产取暖水,实现了蒸氨废水余热的综合利用,降低了工序能耗,具有较好的经济效益和社会效益。     

同位素水精馏非稳态过程制备低氘水的研究与应用

根据水精馏过程中氢、氧稳定同位素的分离特性,以及同位素精馏的稳态和非稳态级联过程的理论分析和研究,应用于水精馏法生产重氧(18O)水的分离过程,在连续生产重氧(18O)水的同时,间歇副产低氘水,使一套同位素分离装置能同时制备二种同位素产品,开发了同位素水的综合制备的技术,提高了分离装置的有效利用率.     

A recycle reactor for measuring hydrogen isotope exchange kinetics under vapour phase and trickle bed conditions

A recycle reactor system has been developed to measure the activities of catalysts for isotope exchange between hydrogen gas and water vapour. To allow testing of reasonably large quantities of catalysts, the reactor was operated with a high recirculating flow of hydrogen gas passing through a saturator to provide the water vapour required for the reaction. In this mode of operation, only a small spiking gas flow was required as feed compared to the very high feed flow that would be required for once-through operation. The reactor was also operated as a trickle bed by recirculating the saturator water. By testing catalysts under both vapour and trickle bed modes, it was possible to investigate the effect of trickling water over the catalyst on the catalytic activity. Kinetic exchange rates under vapour phase operation were calculated from both plug flow and well-mixed reactor models. The former model was found to be the appropriate one for the ranges of operating conditions investigated. However, for trickle bed operation, the well-mixed reactor model was found to be the suitable one. Vapour phase and trickle bed tests done with random bed and structured bed catalysts indicated that the gas phase isotope exchange reaction was not impaired by the presence of liquid water in the reactor.     

Recovery and Recycling of Isopropyl Alcohol Used in Biodiesel Production From Yellow Mustard Oil

The recovery of solvents used during biodiesel synthesis is an important factor in the economic feasibility and sustainability of the entire process. In this study, we looked at the use of isopropyl alcohol (IPA) for oil extraction and biodiesel production, as well as its potential for recovery and recycling. We found that multistage extraction improved oil recovery, with up to 86% oil yield using four stages of extraction at an IPA:mustard flour (volume:weight) ratio of 1.5:1 at room temperature. Using acid–base‐catalyzed transesterification, 99% of the mustard oil was converted to biodiesel. At the end of this process, IPA was recovered from the azeotrope by salting out using potassium carbonate or sodium carbonate. The solubility behavior of the components was evaluated by means of ternary‐phase diagrams of IPA/water/sodium carbonate and IPA/water/potassium carbonate, which determined their liquid–liquid–solid equilibrium constants at ambient pressure and at room temperature. Using 20% (w:w) potassium carbonate, 95% of the IPA was recovered at 99% purity from a starting mixture of IPA containing 13% water. Azeotropic distillation of the IPA–water azeotrope with 10% potassium carbonate resulted in the recovery of 99% of the IPA at 94% purity. These results suggest that IPA is not only a suitable solvent for mustard‐oil extraction but also for salt‐enhanced azeotropic distillation resulting in near‐complete recovery from aqueous solutions.     

Hydrogen Isotope Effects in the Radiolysis of Water

The tritium fractionation between water and radicals formed in the radiolysis of dilute solutions of monomerous methyl methacrylate in H₂O-HTO and D₂O-DTO mixutres was studied. A parallel determination of the tritium content in molecular hydrogen was performed. Also, the isotopic composition of the initial molecular hydrogen was measured in the concentration range 10 to 90 Mol% D₂O of H₂O-HDO-D₂O mixtures. Hydrogen atoms, hydroxyl radicals and molecular hydrogen produced in the radiolysis of these solvents were found to be depleted in heavier hydrogen isotopes. The isotope effects on the composition of hydrogen atoms are discussed in terms of the rate isotope effects in proton transfer. The isotope effects on the composition of hydroxyl radicals are close to those on molecular hydrogen and their extent suggests ionic dissociation of water as a rate-determining step in the process of formation of both products.     

Pyrolysis mechanism of pitch for carbon fiber using tritium tracer method

Tritium has been introduced into three coal tar pitches and a naphthalene pitch by two methods, one by isotope exchange with tritiated water using Pt/Al₂O₃ catalyst, and the other by hydrogenation with tritiated gaseous hydrogen using Ni-Mo/Al₂O₃ catalyst. The tritium-labelled pitches were carbonized up to 1000°C under nitrogen atmosphere. The release behaviors of hydrogen and tritium during the carbonization of tritiated pitches were investigated by comparing the rates of dehydrogenation and detritiation. The results indicate that the hydrogen introduced into the pitch by the isotope exchange is released more rapidly than the original hydrogen in the pitch while the hydrogen introduced into the pitch by the isotope addition is slightly more difficult to release relative to the original hydrogen in the pitch during the pyrolysis of the pitch. Moreover, it was clarified that the extent of development of optically anisotropic texture of the pitch is related not to the hydrogen exchange ratio but to the rate of hydrogen release during pyrolysis.     

应用Aspen Plus筛选DMF废水回收萃取剂

合成革生产过程中产生大量的DMF废水,传统的方法是采用普通精馏回收DMF,但其能耗较高,为了节约能源改用革取结合精馏的新工艺,而其中适宜萃取剂的选择对节能降耗十分重要.因此,利用Aspen Plus对萃取过程进行模拟,确定了适宜的萃取剂为三氯甲烷,当DMF废水浓度为20%时,选择性系数为46.86,单级萃取回收率为33.9%,五级逆流草取回收率为95.1%,具有显著的节能效果.     

Separation of a Biofuel: Recovery of Biobutanol by Salting‐Out and Distillation

The second generation biofuel butanol can be produced by acetone‐butanol‐ethanol (ABE) fermentation, but the separation from the broth is still challenging. Therefore, dipotassium hydrogen phosphate was investigated as salting‐out agent. The ABE fermentation broth was enriched by a prefractionator after being preheated. The enriched ABE solution was salted out by K₂HPO₄ solutions at different temperatures. The water in the supplemented ABE solution was largely removed by the salting‐out method. The energy requirements for the prefractionator and the butanol column were significantly reduced. The total energy demand for the recovery of acetone, butanol, and ethanol by salting‐out and subsequent distillation was optimized. With the salting‐out process, the entire salting‐out and distillation method turned out to be more energy‐saving than the conventional one.     

愈创木酚水汽蒸馏废水的综合利用

介绍了一种由邻氨基苯甲醚经重氮、水解过程生产愈创木酚过程中产生的水汽蒸馏废水的综合利用方法.将愈创木酚水汽蒸馏所得水相直接应用于香兰素的合成,大大减少了香兰素缩合反应所需的投料工艺水,同时省略了愈创木酚水汽蒸馏水相的萃取与废水处理过程,达到节能与循环利用的目的.按公司的生产规模,年可减少约20万t废水,使香兰素绿色生产工艺上了一个新台阶.     

四氢呋喃-甲醇-乙酸甲酯-水热集成双溶剂萃取精馏工艺

针对四氢呋喃-甲醇-乙酸甲酯-水四元物系中存在多个二元共沸物的特点,本工作提出了常规双溶剂萃取和热集成双溶剂萃取两种精馏工艺。基于WILSON方程计算得到热力学数据,并对萃取剂进行了筛选。结果表明,对于四氢呋喃-甲醇和乙酸甲酯-甲醇共沸物系,选用水作为萃取剂最为合适;而对于四氢呋喃-水和乙酸甲酯-水共沸物系,则选用乙二醇作为萃取剂最为合适,且总溶剂比为0.65,乙二醇和水的比例为1.3。在此基础上,以能耗和年总费用(TAC)作为精馏工艺的评价指标,对提出的常规双溶剂萃取和热集成双溶剂萃取精馏工艺进行了模拟,并利用夹点分析技术对双溶剂萃取精馏系统的换热网络进行了优化。研究结果表明,优化后的换热网络其冷公用工程消耗降低44.12%,热公用工程消耗节约42.49%。与常规双溶剂萃取精馏工艺相比,热集成双溶剂萃取精馏工艺其能耗降低约43.29%,节省TAC约26.89%,热力学效率提高了3.25%。可见,热集成双溶剂萃取精馏工艺用于分离以上四元共沸物系,具有较好的技术经济优势。     

Evaluation of a simple batch distillation process for treating wastes from metalworking industries

A simple batch distillation process for the treatment of two types of industrial waste generated in a metalworking factory has been evaluated. Both types of waste are oil‐in‐water emulsions composed of numerous compounds and each type has a high content of water‐soluble species. The water‐soluble nature of the wastes precludes the use of conventional treatment technologies, such as ultrafiltration or chemical emulsion breaking, since they need to be complemented with additional treatment processes that would probably increase the cost considerably. A simple characterization of the liquid–vapour equilibrium and a scale‐up study has demonstrated the applicability of this technology. The process allows 90% of the waste to be recovered as water, thus achieving the required quality limits for discharge into a municipal wastewater treatment plant. An approximate estimation of capital investment and operating costs for an existing case has shown the economic viability of this process. Copyright © 2004 Society of Chemical Industry     

分子筛膜-精馏耦合用于费托合成水相副产物混合醇回收的工艺流程模拟

费托合成油水相副产物混合醇的回收多采用萃取精馏的分离方法,此方法需要配置7个精馏塔和5路循环回路。通过分析发现,流程冗长的关键因素在于混合醇中除甲醇外各个组分均与水产生共沸,而分子筛膜渗透汽化技术不受汽液平衡的限制,因此可以利用分子筛膜渗透汽化技术将混合醇中的水分先脱除,然后再利用精馏技术对混合醇各组分进行分离。本文完成了精馏-膜分离耦合工艺分离混合醇的全流程模拟,并与传统的萃取精馏工艺流程进行对比。精馏-膜分离耦合工艺大幅简化了原有萃取精馏工艺流程,整体能耗降低30%。并根据此流程在陕西延长石油（集团）有限公司建成了国内第一套膜分离-精馏耦合工艺的1000t/a低碳混合醇回收和分离的工业示范装置。     

非均相恒沸精馏分离回收正丁醇的模拟与优化

针对青岛某染料厂现有中性染料母液正丁醇回收率低、废水排放量大和不达标等问题,提出了改进的工艺,以原料水为自夹带剂的非均相恒沸精馏回收正丁醇,用 PRO/II模拟软件考察了各操作参数对冷却水和蒸汽用量的影响,确定了适宜的工艺条件,使回收率由95%提高至98%,废水达标排放,模拟结果与试验值吻合,可用于指导工业生产与设计。     

Manufacturing process of self-luminous glass tube (SLGT) utilizing tritium gas: Design of tritium handling facilities

Tritium, the essential material of self-luminous glass tube (SLGT), is a Β-ray emitting radioactive hydrogen isotope that requires a special handling facility. The design basis of a tritium handling facility is to minimize the operator’s exposure by tritium uptake and the emission of tritium to the environment. To fulfill the requirements, major tritium handling components are located in the secondary containment such as glove boxes (GBs) and/or fume hoods. Besides a tritium recovery system (TRS) and a tritium monitoring system are included in this facilities. To prevent both tritium release out to the room and air in-leakage into the GB, the GB is designed to maintain equal or slightly lower pressure than room atmosphere. TRS is connected to the GB and process loop (PL) to minimize the release of tritium as well as to remove moisture and oxygen in the glove box. TRS is composed of a molecular sieve adsorption bed (MS bed), a nickel catalyst bed, a metal getter, tritium monitors, and a circulation pump. TRS components are regenerated if needed and tritium is recovered for reuse.     

啤酒生产废水资源化研究

在啤酒生产废水常规处理工艺及其出水水质的基础上,采用生物与超滤处理工艺进行深度处理.处理后水质可满足中水回用要求,实现啤酒生产废水资源化利用,如用作啤酒生产冷却水系统与蒸汽锅炉系统的补充水,可节约1/4生产用水,产生123万元的经济效益。     

从工业废水中回收乙酸的方法研究进展

随着我国工业水平的不断提高, 含有乙酸的废水产生量越来越大。乙酸的含量一般在1%～30%(质量分数), 使废水不仅表现为强酸性, 而且化学耗氧量高, 不易直接排放。乙酸与水不易分离也使乙酸废水在工业上难以处理, 研究从废水中回收乙酸的方法具有重要意义。本文简要介绍了近几年国内外从工业废水中回收乙酸的进展, 主要包括膜分离法、吸附法、萃取法、萃取酯化法、精馏法, 并分析了每种方法的优缺点以及当前的研究水平。指出:双极膜电渗析和渗透汽化法适合乙酸质量分数在1%左右的废水处理;吸附法和反应萃取法适用于乙酸含量在10%以下的废水处理, 30%以下的乙酸废水可以借助反应精馏进行分离。最后分析了膜分离法和吸附法处理含乙酸废水的工业应用尚需解决的关键问题。     

萃取-精馏耦合工艺处理环丁砜废水的流程模拟

针对聚芳醚树脂聚合过程产生的环丁砜废水的处理,提出了以二氯甲烷为萃取剂的萃取-精馏耦合新工艺。选用NRTL活度系数模型,采用Aspen plus流程模拟软件对萃取-精馏耦合工艺处理环丁砜废水的过程进行模拟研究,并应用灵敏度分析工具分别对萃取塔和精馏塔进行参数优化。模拟结果表明,当萃取塔的平衡级数为7、萃取相比为1∶1、精馏塔的理论板数为5、进料位置为第3块理论板时,废水中环丁砜的浓度从100g/L降至34mg/L,同时得到质量分数为98.31%的环丁砜,环丁砜的回收率达到99.95%,处理后的水和环丁砜都能够满足在聚芳醚树脂生产过程中循环使用的要求。与现有的四效蒸发工艺相比,萃取-精馏耦合工艺的热负荷降低了约37%,具有非常好的工业应用前景。     

Kinetics of acetic acid esterification over ion exchange catalysts

Computer simulation showed that catalytic distillation is an attractive process for the removal of dilute acetic acid from wastewater. Selection of catalysts and kinetic data have been obtained for the design of the catalytic distillation column. Kinetic measurements were conducted in a batch reactor. Methanol was added to the dilute acetic acid solutions and reacted with the acid in water to form methyl acetate and water. The reaction can be catalyzed by solid acid catalysts. It was found that Amberlyst 15 was an effective catalyst for this reaction. The effects of stirrer speed, reaction temperature, reactant concentration and catalyst loading on reaction rate were investigated. A complete kinetic equation for describing the reaction catalyzed by Amberlyst 15 was developed. This equation can be used in the simulation and design of the catalytic distillation column for removing acetic acid from wastewater.