【作者】 王焱鹏；

【导师】 董群；

【作者基本信息】 大庆石油学院 ， 化学工艺， 2006， 硕士

【摘要】 由于固体的热容量比气体大,同时Geldart A类颗粒具有良好的流化性能。因此,如果利用循环流化床反应器以固-固换热的形式将催化裂化剩余热量置换出来,作为炼油新工艺的能量来源将拥有广阔的工业应用前景。本文的工作是在自制的循环流化床换热系统上进行的,研究首先从建立稳定循环的流化床实验平台入手。实验以3种催化裂化催化剂为循环物料,对内、外循环系统分别进行考察,摸索藏量、松动风及提升风等因素对循环量的影响规律。冷态实验结果表明,催化剂循环量可由提升风和松动风调节控制,适宜的藏量和松动风量可以提高装置的操作稳定性。最终选定内床表观气速2.4m/s,外床2.5m/s;内床松动风0.22m/s、外床0.19m/s;内床藏量5000g,外床6000g为热态实验条件;内床催化剂循环量最高可达45kg/h,外床35kg/h。在热态实验中,模拟现场工况对装置进行加热,考察换热系统的传热效果。在选择的操作条件下,分别以内床、外床为研究对象,摸索床层密度、表观气速、催化剂循环量、床层温度、催化剂粒径、物料性质等因素对传热系数的影响规律。实验结果表明,随着催化剂循环量增加、床层密度下降,传热系数下降;提高床层温度、降低表观气速,传热系数增加;利用较大热容量和小粒径的固体颗粒可以获得高的传热效果。在模型建立过程中,首先,通对系统传热过程进行合理简化,应用颗粒絮团不稳定传热理论建立物理模型;然后,利用拉普拉斯方法对过程控制方程进行求解、变换,给出传热过程的数学模型;最后,综合实验数据,回归求解模型参数,提出固-固换热系统的传热系数计算式。将传热系数预测值与实验值进行比较,误差在15%以内,能满足工程设计的需要。更多还原

【Abstract】 Because the thermal capacity of solid particles is larger than that of gas and the particles ofGeldart A have good fluid property, energy source of the new petroleum refining process willhave very broadly perspectives of application if the residual heat of FCC can be taken out bysolid-solid heat transfer in circulating fluidized bed,.The study was carried out with heat transfer system of homemade circulating fluidized bed.The inner and the outer circulating systems were studied separately by using three kinds of FCCcatalyst as circulating materials. The influence of catalyst inventories, aeration air quantity andmain air quantity on circulating catalyst rate was studied too. The results of experiments showthat the proper catalyst inventories and the aeration air quantity can enhance the operationstability of equipments. Lastly the conditions which were ascertained are as follows: fluidizationvelocity of inner tube 2.4m/s, fluidization velocity of outer tube 2.5m/s;aeration air quantity ofinner tube 0.22m/s, aeration air quantity of outer tube 0.19m/s;catalyst inventories of inner tube5000g, catalyst inventories of outer tube 5000g;catalyst circulating rate of inner tube 43kg/h ,catalyst circulating rate of outer tube 35kg/h.The efficiency of heat transfer system was studied by simulating the situation of practicalproduction in heat transfer experiments. The influence of suspension density, fluidizationvelocity, beds temperature, diameter of catalyst particles and material properties on heat transfercoefficients was studied with the proper conditions. The results of experiments show that thesuspension density and the heat transfer coefficients decrease with catalyst circulating rateincreasing;the heat transfer coefficients increase with bed temperature increasing, thefluidization velocity and the particles diameter decreasing;the good efficiency of heat transfercan be obtained by using solid particles with the larger thermal capacity.Firstly the heat transfer process of system was simplified, the physical model was built byusing the instability theory of particle floc. Then the equation of process operation was resolvedand the mathematic model of heat transfer process was given by Laplace equation. Lastly theparameter of model was regressed and the equation of heat transfer coefficients of the solid-solidheat transfer system was put forward according to experiment results. The forecast value and theexperiment value of heat transfer coefficients were compared. It is satisfied with the needs ofengineering design that the error is less than 15%.更多还原