Diethyl carbonate is an important green solvent,and widely used in the lithium battery industry.The way to produce diethyl carbonate from the transesterification reaction of dimethyl carbonate and ethanol using reactive distillation is the mainstream method at present. The reaction is divided into two steps,therefore process parameters' control to improve reactant conversion and product yield becomes an important problem.In this paper,the reactive distillation column with kinetic equation by experiment and UNIQUAC thermodynamic model was simulated by Aspen Plus.The effects of feeding position,reflux ratio,and the feeding molar ratio,on the performance of the reactive distillation column were studied in detail by using Aspen Plus.The results showed that the reactive distillation column's best conditions were reflux ratio 4.5～5.5,mix feed position 20~(th),feeding molar ratio 2.5:1,reactive zone 2～31,and the space velocity was less than 0.18 hr~(-1).The simulation results had some reference worthiness to the technological design and optimization for producing diethyl carbonate.

To improve the extraction of gold from electronic waste,statistical methods were used to analyze the impact of different factors affecting the extraction of Ao (III) using methyl isobutyl ketone (MIBK) as solvent.The Plackett-Burman experimental design was used to determine the main influencing factors which are phase ratio,extraction time and extraction temperature.Using these three factors as variables,the extraction operation conditions were optimized by Response Surface Methodology (RSM).The optimum phase ratio was 0.59 (water to MIBK) ,extraction time 9.0 rain and extraction temperature 20℃.Under this optimized condition,the extraction rate of Au(III) was 98.36% which was much higher than that under other conditions.The MIBK-Au(III) was regenerated with a 5 solution of oxalic acid,and the recovery of stripped gold was 96.2%.

As a fuel oxidizing agent,methyl tert-butyl ether (MTBE) is added to gasoline in replacement of tetraethyl lead to enhance octane number. The addition of MTBE also improves the combustion efficiency and therefore decreases the emission of pollutants like CO and O3. On the other hand,because of gasoline spills,mainly due to leaking underground storage tanks,MTBE has become a prevalent contaminant in groundwater. The reason for such widespread contamination is that MTBE is highly soluble in water and recalcitrant to biodegradation. The chemical characteristics of MTBE make it a challenge to treatment in the natural environment. Biological treatment of soil and groundwater is expected to be a cost-effective technique. It was reported that MTBE was able to degrade through co-oxidation or could be used as a carbon and energy source by many microorganisms. In China,the studies on MTBE removal by bioremediation techniques are still at their infancy for both fundamental research and on-site application. Based on previous studies,the reported microorganisms able to degrade MTBE were summarized,and then emphasis was put on the key catabolic enzymes involved in MTBE degradation.

对负压蒸氨节能新工艺进行了模拟研究,考察了操作压力对氨水相对挥发度、节能效果以及设备操作温度的影响,新工艺可降低能耗50%左右,同时节省设备投资,具有良好的推广前景.

计算流体力学(CFD)是研究精馏塔内气液两相流动和传质的重要工具.本文介绍了板式塔和填料塔内气液流动状况,塔板上和填料层的流体力学模型,论述了国内外CFD技术在精馏塔流场模拟方面的应用,指出了CFD技术在精馏领域的发展方向,对于板式塔,应充分考虑气液两相间的相互作用,对于填料塔,应根据填料的具体形状建立每个孔道的流体力学方程,进行更接近实际的三维两相流模拟.