【作者】 鲁丰乐；

【导师】 应卫勇；

【作者基本信息】 华东理工大学 ， 化学工艺， 2010， 博士

【摘要】 费托合成制备液体燃料是解决我国能源供应不足和保障能源安全的重要途径之一,费托合成反应动力学的研究和反应器的数学模拟对费托合成反应器设计放大和优化操作具有重要的指导意义。在研究蛋壳型钴基催化剂性能的基础上,建立了CO消耗速率、碳链增长概率因子α的集总动力学模型。应用所建动力学模型,建立了蛋壳型钴基催化剂的扩散—反应模型,研究了反应压力、温度、催化剂颗粒直径对催化剂颗粒内各组分浓度分布和温度分布的影响。建立了管壳型固定床反应器的一维拟均相数学模型,对合成油中试装置工况模拟,讨论合成油中试装置操作条件和反应器装置参数对反应器性能的影响。采用SEM、BET、XRD、TPR等表征方法对催化剂进行表征,结果表明蛋壳型催化剂为中孔结构,表面钴物种是C0304,分散度良好,适宜焙烧温度为450℃,还原程序为不同氢含量的气氛,程序升温,最高还原温度为380℃。在直流流动等温积分反应器中研究蛋壳型钴基催化剂的反应性能,结果表明提高压力、提高温度、增加H2／CO摩尔比和降低气体空速都可提高CO转化率,提高压力、降低温度、减小H2／CO摩尔比和降低气体空速都有利于重质烃生成,提高产物中C5+的选择性和Cs+的收率。并且在压力3.5MPa,温度225℃,H2与CO摩尔比应在2.0,气体空速为1000h-1的反应条件下,费托合成反应运行400h,CO和H2转化率保持在0.72、0.70,产物甲烷、低碳烃、油和蜡的产量保持8.9μg/s、6.7μg/s、25.3μg/s和42.2μg/s, C5+收率保持在171.2g/Nm3,催化剂反应稳定性良好。在反应压力1-5MPa,温度190-240℃,合成气中H2／CO摩尔比为1.40～2.50,空速为500-5000h-1的实验条件下,蛋壳型钴基催化剂的集总动力学模型为：通过统计检验和残差分析,CO消耗速率模型和碳链增长概率因子α模型是适宜的,计算值和实验值符合良好。利用所建集总动力学模型,分析不同反应压力、温度、H2／CO摩尔比和气体体积空速对费托合成反应结果的影响。建立了蛋壳型钴基颗粒催化剂的扩散-反应模型,在反应压力3MPa、温度225℃、H2／CO摩尔比2.0和空速1000h-1的条件下,采用正交配置法模拟计算催化剂颗粒内部CO、H2和CH4、C3H8、C10H22的浓度和浓度变化梯度以及颗粒内温度分布,结果表明在催化剂颗粒内活性部位外层到内层温度呈上升趋势,最大温差为2.15℃,在催化剂颗粒活性部位的内层H2／CO摩尔比增大,在颗粒活性部位的内层不利于重质烃的生成。利用颗粒催化剂的扩散-反应模型,分析反应压力、温度、催化剂颗粒直径对费托合成的反应结果的影响。反应压力提高,催化剂颗粒内CO、H2浓度有所下降,颗粒内H2／CO摩尔比增大,催化剂颗粒内温度略有升高,颗粒内最大温差为2.61℃,产物CH4、C3H8、C1oH22的浓度略有增加；反应温度的提高,催化剂颗粒内温度升高显著,颗粒内最大温差为2.64℃,CO和H2的有效扩散系数增加,颗粒内H2／CO摩尔比增大,催化剂颗粒内CH4、C3H8、C1oH22的浓度都有所增加,CH4的浓度增加尤为显著,表明温度的提高不利于重质烃的生成；催化剂颗粒的直径减小,催化剂催化剂颗粒内温度降低,颗粒内最大温差为1.46℃,颗粒内CO、H2的浓度有所增加,颗粒内H2／CO摩尔减小,可见较小颗粒的催化剂可减少反应物和产物的扩散阻力,有利于重质烃的生成。应用集总动力学模型,建立了管壳型固定床费托合成反应器的一维拟均相模型。在合成油中试试验条件下工况模拟结果为：CO、H2转化率分别为0.320、0.321,反应器出口CH4、C3H8、C10H22、C22H46的流量分别为780.16、251.77、114.14、140.80kg·h-1,产物Cs+的质量分数为80.52%,C5+的时空产率为119.36g·(L催化剂·h)-1,与中试试验值相对误差不超过5%,催化床层温度计算值与模型值绝对误差在0.23-2.30K之间,最大相对误差为1.06%,床层压力降计算值为0.629MPa与试验值0.630MPa接近,表明模型计算值与试验值吻合良好。探讨合成油中试装置操作条件和反应器装置参数对反应器性能的影响。模拟结果显示,提高反应器进口温度,催化床层温度升高,反应器出口温度变化不大,CO转化率提高,产物中C5+的质量分数有所减少,C5+的时空收率上升；提高反应器进口压力,床层温度和热点温度升高,甲烷的质量分数增大,C5+的质量分数有所减小,C5+时空产率略有增加；增大反应器进口气体空速,床层温度和热点温度下降,产物中C5+的质量分数增大,C5+的时空收率有所减少；增大反应器进口气体中H2／CO摩尔比,床层温度和热点温度降低,产物中Cs+的质量分数减低,Cs+的时空收率减小；提高管外沸腾水温度,催化床层温度、热点温度和反应器出口温度升高,产物中C5+的质量百分数明显减小,C5+的时空收率有所增大；增加反应器催化床层高度,催化床层温度降低,产物中C5+的质量分数明显增大,但C5+的时空收率有所降低；增大反应管管径,催化床层的温度和热点温度升高,产物中C5+的质量分数明显减小,C5+的时空收率增大。更多还原

【Abstract】 The technology of producing liquid fuel with Fischer-Tropsch Synthesis is an important way to solve China’s energy shortage and guarantee the energy safety. The study on reaction kinetics and mathematical simulation of reactors guides the scale-up design and optimal operation of Fischer-Tropsch Synthesis reactors. In this thesis based on the study on eggshell Co-based catalyst’s performance the lumping kinetics model consisted of CO consumption rate and carbon chain growth factor a model was established. And the diffusion-reaction model in this catalyst particle was proposed and the effects of reaction pressure、temperature and the particle diameter on the components concentration profile and temperature profile in the particle was studied. Furthermore, the homogeneous one-dimensional model of the tube-shell fixed-bed reactor was established and the mode simulation of synthesis oil pilot test prove the model right, and the effects of the operating conditions and the device parameters on the reactor performance were discussed in detail.With the characterization methods of SEM、BET、XRD、TPR and so on, it was summarized that the surface cobalt species was Co3O4 with good dispersion, and fit calcinations temperature was 450℃. The reduction procedure was temperature programmed with different hydrogen content of the atmosphere and the maximum reduction temperature was 380℃. The experiments was conducted in the isothermal integral reactor and the effects of pressure、temperature、H2/CO and sapce velocity on the reaction results was studied. in the reaction conditions of pressure 3.5MPa, temperature 225℃, H2/CO 2.0 and space velocity l000h-1, the steady experiment was carried on for 400 hours. The results showed that CO and H2 conversation kept 0.72、0.70, the produce output of CH4、lower gydrocarbons、oil and wax kept 8.9μg/s、6.7μg/、25.3μg/s and 42.2μg/s, and C5＋yield kept 171.2g/Nm3. These proved that the catalyst’s performance had good stability.The lumping kinetics model was showed as: Through statistical tests and residual analysis, this model was appropriate. With the lumping kinetics model, the effects of different reaction conditions including reaction pressure, temperature, H2/CO and space velocity to the reaction result was analyzed.The diffusion-reaction model in the eggshell Co-based catalyst particle was established. In the condition of pressure 3MPa, temperature 225℃, H2/CO 2.0 and space velocity 1000h"1, the orthogonal collocation method was used to calculate the concentration profile and the temperature profile in the catalyst particle. The simulation results showed that the temperature rised from the outer to inner in the active sites and the maximum temperature difference was 2.15℃and the mole ratio of H2/CO increased. With this diffusion-reaction model, the effects of pressure、temperature and the particle diameter on the reaction result were given. The higher pressure and temperature caused the particle temperature rise and the concentration of CH4、C3Hg、C10H22 small increase. The smaller size catalyst particle engendered the temperature decrese and the maximum temperature difference was 1.46℃. So the small particle would reduce the diffuse resistance and pomote the formation of heavy hydrocarbons.The homogeneous one-dimensional model of the tube-shell fixed-bed reactor was established and the mode simulation of synthesis oil pilot test demonstrated that the outlet flow rate of CH、C3H8、C1oH22、C22H46 was 780.16、251.77、114.14、140.80kg-h-1, C5＋weight pecentage was 80.52% and Cs＋space time yield was 119.36g-(L·h)-1, which was agreement with the pilot test reslusts. The profiles of bed temperature and pressure from the model were consistent to the practical results. The effects of different operating conditions and device parameters to the reactor performance were studied. The increase of inlet temperature、inlet pressure、boiling water temperature and tube diameter would cause the upward migration of catalyst-bed temperature cures, the increase of CO conversion, the decrease of C5＋weight selectivity and increase of C5＋space time yield. The increase of inlet space velocity would cause the downward migration of temperature cures, the increase of C5＋weight selectivity and increase of C5＋space time yield. The increase of H2/CO would cause the downward migration of temperature cures, the decrease of C5＋weight selectivity and C5＋space time yield. The increase of the catalyst-bed height would cause the downward migration of temperature cures, the increase of C5＋weight selectivity and the decrease of C5＋space time yield. The increase of would cause the upward migration of temperature cures, the decrease of C5＋weight selectivity and the increase of C5＋space time yield.更多还原