【作者】 吕树祥；

【导师】 米镇涛；

【作者基本信息】 天津大学 ， 化学工艺， 2004， 博士

【摘要】 过程强化是一种高效、节能、清洁、安全、可持续发展的化工新技术,代表化学工程与技术发展方向。反应与分离技术的集成是过程强化的重要途径,将化学反应与液-液萃取集成在一个设备里进行,是一种典型的反应与分离的集成,反应与萃取两个过程互相促进,可以提高反应的转化率和选择性、产物的分离效率和能量的利用率。气体既是反应物,又是搅拌介质的气-液-液三相反应萃取是一种新型的过程强化技术。本文以空气-水-蒽醌工作液为实验物系,对气-液-液三相反应萃取过程中流体力学、气-液传递、气-液反应和液-液传递规律进行了系统研究。在筛板塔内,研究了气-液-液三相流体力学性质。测定了气含率和分散相滞液率,讨论了气相、分散相和连续相流速对气含率和分散相滞液率的影响; 提出了用于预测气-液-液三相体系的气含率和分散相滞液率的关联式,分散相滞液率关联式的预测值与实验结果的平均相对偏差为7.3%,气含率关联式的预测值与实验结果的平均相对偏差为7.1%。研究了气-液-液三相系统轴向返混特性和传质规律,讨论了气体对分散相和连续相轴向返混的影响; 提出了适用于气-液-液三相体系中,分散相和连续相轴向扩散系数的关联式。在筛板萃取塔内,研究了气-液-液萃取过氧化氢过程。提出了气-液-液三相筛板萃取塔总板效率的关联式,关联式计算结果与实验值的最大偏差为5.6%; 建立了气-液-液三相萃取过程数学模型,模型计算结果与实验数据有较好的吻合,平均相对偏差小于10%; 并用模型对气-液-液三相萃取生产过氧化氢过程进行了预测,达到相同的分离效果,气-液-液三相萃取所需塔板数比普通液-液萃取降低30%~40%。研究了气-液-液三相反应萃取制备过氧化氢过程动力学。通过理论分析和实验验证,确定氢蒽醌氧化反应受氧气传质控制,过氧化氢的萃取速率受反应和过氧化氢传质共同控制。在此基础上,建立了反应萃取动力学模型,求取了模型参数,为气-液-液三相反应萃取过程的数学模拟和设计提供了依据。在筛板萃取塔内,研究了气-液-液三相反应萃取制备过氧化氢过程。考察了各相流速、塔板开孔率等对氢蒽醌氧化反应和过氧化氢萃取的影响; 建立了气-液-液三相反应萃取数学模型,模型计算结果与实验数据有较好的符合,平均相对偏差小于15%; 并在工业小试装置上进行了验证,验证和模型模拟结果均表明,在一个萃取塔内,采用反应萃取技术生产过氧化氢是可行的。更多还原

【Abstract】 Process Intensification presents one of the most important trends in today’s chemical engineering and technology. It is a compact, safe, energy-efficient and environment-friendly sustainable technology. One of the most prominent methods of Process Intensification is the integration of chemical reaction and physical separation in one unit。 The integration of reaction and liquid-liquid extraction often leads to a significant reduction in investment and operating costs. The economic benefit may be caused by a reduction of raw material use, diminution of recycle streams by higher rates of conversion, improvements in selectivity, separation efficiency and energy integration. The gas-liquid-liquid three-phase reactive extraction is one of novel technologies for Process intensification. In the gas-liquid-liquid three-phase reactive extraction system, the gas phase works as one of reagents as well as agitating media. The theories about chemical reaction, mass-transfers of gas-liquid and liquid-liquid have been investigated for the oxygen-water-anthraquinone working solution three-phase reactive extraction system. The hydrodynamic characteristics of air-water-anthraquinone working solution three-phase system in a sieve plate extraction column were investigated. The holdups of gaseous and dispersed phases were measured, respectively. The effects of the superficial velocity of gaseous, dispersed and continuous phases on the holdups of gaseous and dispersed phases were investigated. Correlations for the prediction of holdups of gaseous and dispersed phases in air-water-anthraquinone working solution three-phase system have been proposed. Comparison of the predicted data with correlations and experimental data shows that they are quite satisfactory agreement and the average relative deviations are 7.3% for dispersed phase holdup and 7.1% for gas phase holdup, respectively. The back-mixing characteristics and the mass-transfers of the gas-liquid-liquid three-phase system have been investigated. The effects of superficial velocity of gaseous, dispersed and continuous phases on the diffuse coefficients of continuous and dispersed phases were investigated. Correlations for the prediction of diffuse coefficients of continuous and dispersed phases in air-water-anthraquinone working solution three-phase system have been proposed. Extraction of hydrogen peroxide by means of deionized water from anthraquinone working solution was carried out in a gas-agitated sieve plate extraction column. The effects of the superficial velocity of air, dispersed phase and continuous phase on overall plate extraction efficiency have been investigated. The corrections for the prediction of overall plate extraction efficiency were presented. The correlation proposed to predict the overall plate extraction efficiency in air-water-anthraquinone working solution three-phase system agreed satisfactorily with experimental data with a maximum absolute deviation of 5.6%. A new design method for gas-liquid-liquid three-phase extractors is developed based on the multistage countercurrent extraction model. The calculated data by the model agreed well with experimental data and the average relative deviation was less than 10%. Moreover, the model was used to predict a gas-agitated sieve plate extraction column for industrial production of hydrogen peroxide. The results show that the plate numbers of gas-agitated sieve plate extraction column is 30%~40% less than that of liquid-liquid sieve plate column. Kinetics of the reactive extraction process for preparing hydrogen peroxide in oxygen-water-anthraquinone working system has been investigated. Kinetics runs have been carried out in a semi-batch reactor. The reaction rate is governed by the transport of oxygen through gas-liquid interface. The extraction rate is controlled by the reaction for producing hydrogen peroxide and the transport of hydrogen peroxide from organic phase to water. The kinetics expression is given by analysis and regression of the experimental data. The oxidation reaction of the hydrogenated anthraquinone working solution by oxygen and the extraction of hydrogen peroxide from the working solution with deionized water were carried out simultaneously in a sieve plate column. The effects of free area of the sieve plate, both oxygen and working solution superficial velocities on the conversion of 2-ethylanthrahydroquinone and the extraction efficiency of hydrogen peroxide were investigated, separately. The results showed that the oxidation and the extraction do not hamper each other, on the contrary, the presence of gas in the column can promote the transfer of hydrogen peroxide from the organic phase to the aqueous phase, therefore, the conversion of the hydrogenated anthraquinone oxidation and the extraction efficiency of hydrogen peroxide increased with the increase of gas superficial velocity. In addition, a mathematical model for the simulation of the gas-liquid-liquid reactive extraction process was developed. The predicted values were compared with the experimental data at different conditionsand the agreement was found to be quite satisfactory for the production of hydrogen peroxide in a sieve plate column. This reactive extraction process was also performed in pilot plant, and the results shown that it is feasible to industrially produce hydrogen peroxide by the reactive extraction process.更多还原