【作者】 孙宝昌；

【导师】 邵磊；

【作者基本信息】 北京化工大学 ， 化学工程与技术， 2012， 博士

【摘要】 旋转填充床（即超重力机，RPB）是一种新型的强化相间传质和多相混合的设备，主要由装有填料的转子组成。由于转子的高速旋转，使流经转子填料上的液体受到远大于地球重力的离心力的作用（通常为几十到几百个重力加速度），经过液体和填料间的持续碰撞，液体的湍动效果、表面更新速度都得到了加强，从而大幅度提高了RPB中的微观混合和传质效果。鉴于RPB在强化传质和混合方面具有独特的优势，该设备已经应用于气体吸收、脱硫、纳米材料制备、水处理、精馏等化工过程。多组分气体耦合吸收是一种近年来兴起的吸收处理方法。采用新的技术进行耦合吸收能减少生产工序和大幅降低生产成本，使生产企业的综合效益得到大幅提高。本论文主要进行了超重力机中耦合吸收CO₂和NH₃的机制和规律的研究，探索超重力环境下各工艺条件对耦合吸收NH₃和CO₂过程的影响规律，研究了RPB中盐溶液耦合吸收NH₃和CO₂制备无机微纳米材料，为NH₃、CO₂以及相关盐溶液的资源化利用提供新的解决途径。主要内容如下：1、以RPB为实验装置，对水和盐溶液耦合吸收NH₃和CO₂的过程特征和机制进行研究。通过采用正确的积分路线，衡算得到了精确的RPB设计方程和分区域设计方程，并建立了RPB中耦合吸收NH₃和CO₂时的吸收反应传质模型，经过验证，传质系数的预测值和实验值一致性较好，误差范围在百分之十以内。2、研究了水单独或耦合吸收NH₃和CO₂时，各工艺参数如氨碳比、气体和液体体积流量、超重力机转速、体系温度等对NH₃和CO₂吸收传质效果的影响规律。获得本实验的最适宜操作条件：转速为1000rpm，液体流量为200L h^-1，气体流量为2400L h^-1，氨碳比为2，温度为293K。在最适宜条件下NH₃的吸收率可以达到99.2%，传质系数为1.8×10^-4mol Pa^-1 m-3s^-1；CO₂的吸收率可以达到50.6%，传质系数为2.6×10^-5mol Pa^-1 m-3s^-1。3、研究了超重力机中饱和氯化钠溶液耦合吸收NH₃和CO₂时，各操作参数如气体和液体体积流量、超重力机转速、氨碳比、体系温度等对NH₃和CO₂传质系数的影响规律。确定了实验条件下饱和氯化钠溶液耦合吸收NH₃和CO₂的最适宜工艺参数：转速为800rpm，液体流量为25L h^-1，气体流量为1100L h^-1，氨碳比为2，温度取室温293K，在该条件下，NH₃的吸收率可以达到99.04%，传质系数为7.4×10^-5mol Pa^-1 m-3s^-1，CO₂的吸收率可以达到42.2%，传质系数为8.1×10^-5mol Pa^-1 m-3s^-1。4、进行了超重力机中CaCl₂溶液耦合吸收NH₃和CO₂制备纳米CaCO₃的研究。探索体系温度、超重力机转速、液体循环量、原料液浓度、气体流量等操作参数对CaCO₃颗粒物性的影响，获得了本实验中的最适宜工艺参数：温度为293K、转速为1000rpm、气体体积流量是2400L·h^-1、液体体积流量是200L·h^-1、初始CaCl₂浓度为0.2mol·L^-1、CO₂和NH₃的初始浓度分别为7%和14%。在最佳实验参数下，制备出的纳米CaCO₃产品的颗粒度大约为50nm，粒度分布为10-80nm。该方法为CaCl2废液以及NH₃和CO₂气体的资源化利用提供了一条有效途径。5、进行了RPB中氯化镁溶液耦合吸收NH₃和CO₂制备碱式碳酸镁的研究。通过实验对产物的XRD，SEM分析，考察了RPB转速、气体流量、液体流量及氯化镁溶液的初始浓度、反应温度等各操作条件对产物形貌、结构以及尺寸的影响规律。获得了在本实验参数范围内的最适宜操作参数：转速1100rpm，液体流量300L h^-1，气体流量1000L h^-1，氯化镁溶液的初始浓度为0.3mol·L^-1，CO₂和NH₃的初始浓度分别为6%和12%，反应温度为343K。在该条件下，得到了碱式碳酸镁的平均粒径为5.3μm，纳米片厚度为25nm，粒度分布2.8-7μm的碱式碳酸镁。随着对该方法的进一步深入研究，可望为卤水以及含NH₃和CO₂气体的资源化利用提供了一条新的解决途径。更多还原

【Abstract】 A rotating packed bed （RPB, also called Higee device） is a novelequipment for the intensification of mass transfer and multiphase mixing.It consists mainly of a packed rotor. Due to the high-speed rotation of therotor, liquid is submitted to the action of a strong centrifugal force,usually dozens to thousands times larger than the gravitationalacceleration on the earth, when flowing through the packed rotor.Because of the continuous collision between liquid and packing, theturbulence and surface renewal rate of the liquid is enhanced, leading to asignificant increase of the mass transfer and micromixing efficiency inthe RPB. In view of the unique properties of RPB in mass transfer andmixing, it has been widely used in chemical processes such as absorption,desulfurization, nanomaterials preparation, water treatment, distillationand so on.Simultaneous absorption of multicomponent gases is an emergingabsorption process in recent years. The production processes and cost canbe reduced by using the simultaneous absorption processes, resulting in the increase of comprehensive benefits of enterprises. This dissertationinvestigated the mechanism and rule of the simultaneous absorption ofCO₂and NH₃into water in an RPB. The effects of different operationconditions on the absorption process of CO₂and NH₃into water in theRPB were studied. In order to develop a feasible methodology for theutilization of NH₃, CO₂and certain salt solution, the preparation ofinorganic micro/nano-materials by simultaneous absorption of NH₃andCO₂in salt solution in an RPB was also studied. The main researchcontents are as follows:1. Investigated the mechanism and characteristics during thesimultaneous absorption of CO₂and NH₃into water, NaCl solution,CaCl2solution, and MgCl₂solution in an RPB. The precise designequation and part design equation of an RPB were deduced by adoptingthe practical boundary conditions. A reaction mass-transfer model wasestablished and used for the prediction of the mass-transfer coefficient（KGa） of the simultaneous absorption of CO₂and NH₃into water in anRPB. By the comparison of the predicted value and experimental value,we found that the deviation is within10%, and the model exhibits goodprediction ability for KGa value in the RPB.2. Investigated the effects of different operating conditions,including NH₃/CO₂molar ratio, rotation speed, liquid volumetric flowrate, gas volumetric flow rate and temperature, on the mass-transfer coefficient of NH₃and CO₂during the simultaneous or separateabsorption of CO₂and NH₃into water in an RPB. And the optimaloperating conditions of a rotation speed of1000rpm, a liquid volumetricflow rate of200L h^-1, a gas volumetric flow rate of2400L h^-1, aNH₃/CO₂molar ratio of2and a temperature of293K were obtained inthis simultaneous absorption process. A NH₃absorption rate of99.2%, aNH₃mass-transfer coefficient of1.8×10^-4mol Pa^-1 m-3s^-1, a CO₂absorption rate of50.6%and a CO₂mass-transfer coefficient of2.6×10^-5mol Pa^-1 m-3s^-1can be achieved under the optimal operating conditions.3. Investigated the effects of different operating conditions,including rotation speed, liquid volumetric flow rate, gas volumetric flowrate, NH₃/CO₂molar ratio and temperature, on the mass-transfercoefficient of NH₃and CO₂during the simultaneous or separateabsorption of CO₂and NH₃into saturated NaCl solution in an RPB. Andthe optimal operating conditions of a rotation speed of800rpm, a liquidvolumetric flow rate of25L h^-1, a gas volumetric flow rate of1100L h^-1,a NH₃/CO₂molar ratio of2and a temperature of293K were obtained inthis simultaneous absorption process. A NH₃absorption rate of99.04%, aNH₃mass-transfer coefficient of7.4×10^-5mol Pa^-1 m-3s^-1, a CO₂absorption rate of42.2%, a CO₂mass-transfer coefficient of8.1×10^-6mol Pa^-1 m-3s^-1can be achieved under the optimal operating conditions.4. Investigated the preparation of nano-CaCO₃by simultaneous absorption of NH₃and CO₂into CaCl2solution in an RPB, andinvestigated the effects of different operating conditions, includingreaction temperature, rotation speed, liquid volumetric flow rate, gasvolumetric flow rate and initial concentration of CaCl₂solution, on thecharacteristic of nano-CaCO₃. And the optimal operating conditions of arotation speed of1000rpm, a liquid volumetric flow rate of200L h^-1, agas volumetric flow rate of2400L h^-1, a NH₃/CO₂molar ratio of2, atemperature of293K, a NH₃concentration of14%and a CO₂concentration of7%were obtained in this process. The nano-CaCO3witha mean size of50nm, a particle size distribution of10-80nm wasprepared under the optimal operating conditions. The process provides apromising pathway for the utilization of CaCl₂wastewater and NH₃-andCO₂-containing exhausts as resources.5. Investigated the preparation of basic magnesium carbonate （BMC）by simultaneous absorption of NH₃and CO₂into MgCl2solution in anRPB, and investigated the effects of different operating conditions,including rotation speed, liquid volumetric flow rate, gas volumetric flowrate, reaction temperature and initial concentration of MgCl₂solution, onthe shape, structure and size of BMC. And the optimal operatingconditions of a rotation speed of1100rpm, a liquid volumetric flow rateof300L h^-1, a gas volumetric flow rate of1000L h^-1, a NH₃/CO₂molarratio of2, a temperature of343K, a NH₃concentration of6%and a CO₂ concentration of12%were obtained in this process. The BMC with amean size of5.3μm, a nano-slice microstructure of25nm, a particle sizedistribution of2.8-7μm was prepared under the optimal operatingconditions. This process shows potentials for the utilization of MgCl₂wastewater and NH₃-and CO₂-containing exhausts as resources.更多还原