| Liquid fuel synthesizing by Fischer-Tropsch synthesis from coal or natural gas has a significant meaning in resolving the problems of the energy shortage and environmental contamination caused by traditional utilization of coal and petroleum. Due to the directive significance for reactor scaling up and optimization, the study on Fischer-Tropsch reaction kinetics, reactor simulation and separation between products and catalyst in slurry bubble column reactor (SBCR) is drawing more and more attentions. On the basis of studying the Co/AC catalyst's reaction performance, the intrinsic CO consumption rate model in an isothermal integral reactor, global CO consumption rate model in a stirred tank reactor and detailed product distribution model were established. Whereafter, the mathematical model of slurry bubble column reactor for Fischer-Tropsch synthesis was achieved and the effects of operation variables on reaction performance of SBCR were discussed in detail.The characterization results of SEM, N2 adsorption-desorption, H2-TPR on Co/AC catalyst indicated that pores on catalyst surface were constituted by meso pores and micro pores, the surface active cobalt species was Co3O4, the activation of Co/AC catalyst could be carried out with a temperature between 350～400℃under pure H2 and atmospheric pressure. The evaluation experiment of Co/AC catalyst reaction performance was conducted in an isothermal integral reactor and the effects of operating conditions on reaction results were discussed. It was indicated from the results that a reaction condition containing high temperature, pressure, value of H2/CO in syngas and low space velocity (Sv) was propitious to increase the reaction activity of catalyst and the conversion of CO. Meanwhile, the increase of pressure and decrease of temperature, Sv and H2/CO would result in the increase of selectivity of hydrocarbons and alcohols with high carbon number. The optimum condition selected was as follows:reaction temperature:230℃, reaction pressure:4.0 MPa, molar ratio of H2 to CO:2, Sv:2000 h-1. Under this condition, the conversion of CO was 19.92%, the selectivity of CH4, C2-4, C5+, C1-5OH, C6+OH was 22.36%,24.34%,32.61%,14.35% and 6.34% respectively.The product distributions of FTS over a Co/AC catalyst under different operation conditions were investigated. A detailed explanation on the distributions with carbon number and operation conditions, taking the re-adsorption of alkenes and the following secondary reaction into consideration, was given. The contents of alcohols, alkenes and alkanes declined with the increasing carbon number, the declining tendency of alkanes was much slighter than that of alkenes and alcohols. It was also found that higher temperature, space velocity, H2/CO in feed gas and lower pressure is preferential for light hydrocarbons and alcohols and is against the chain propagation. The effect of space velocity on the product distributions especially the light products is not obvious. It is noticed that lower temperature, space velocity, H2/CO and higher pressure lead to higher contents of alcohols; higher temperature, H2/CO and lower space velocity lead to higher alkanes, the effect of pressure on the amounts of alkanes is not significant; higher space velocity and lower temperature, pressure, H2/CO are preferential for alkenes.The intrinsic CO consumption rate model in an isothermal integral reactor was achieved under the operating conditions:temperature from 220℃to 250℃, pressure from 2.0 MPa to 4.0 MPa, the molar ratio of H2 to CO from 1.0 to 2.5 and the space velocity from 2000h-1 to 3500 h-1 and it could be expressed as follow:The global CO consumption rate model in a stirred tank reactor under the operating conditions:temperature from 210℃to 225℃, pressure from 2.0 MPa to 4.0 MPa, the molar ratio of H2 to CO from 1.0 to 2.5 and the space velocity from 400 h-1 to 1000 h"1 was obtained and it could be expressed as follow:The content distributions of alkanes, alkenes and alcohols with carbon number could be approximated as two intersected lines respectively according to the experimental results under different operating conditions. Based on the molar fractions of components (Xi) with different carbon number (n) obtained from experiment, the correlation between Xi and n could be achieved by linear regression, coefficients of expression between Xi and n was correlated with operating variables. Whereafter, the expressions of product formation rate (product distribution model) could be described as follow:The results of statistical tests and relative error analysis showed that the intrinsic CO consumption rate model, global CO consumption rate model and detailed product distribution model were appropriate. On the basis of global CO consumption rate model, detailed product distribution model and sedimentation-dispersion model of catalyst, a steady-state one-dimensional mathematical model of slurry bubble column reactor for Fischer-Tropsch synthesis was established. The mathematical simulation of slurry bubble column reactor for Fischer-Tropsch synthesis was carried out under typical industrial operating conditions:temperature 230℃, pressure 3.0 MPa, gas flow 5×105Nm3·h-1, catalyst content in slurry phase 30%, reactor diameter 5.0 m and the composition of feed gas:yH2=0.60,yCO=0.30,yN2=0.10. The results were listed as follows:static bed height:18.72 m, operating bed height:25.55 m, average gas holdup:0.27, superficial space velocity:0.43 m·s-1, mass of paraffin:212.29t, mass of catalyst:90.98 t, gas composition in the outlet:yH2=53.57%, yco=24.60%,yN2=10.88%,yCH4=1.40%, yC3=1.24%, yC8=0.25%, yC23=0.01%,yCH3OH=0.21%,yC3OH=0.18%,yC8OH=0.04%, CO conversion:24.64%, C2～4 selectivity:46.19%, annual yield:80485 t·a-1, liquid hydrocarbons selectivity:24.61%, annual yield:47228 t·a-1, alcohols selectivity:12.85%, annual yield:32715 t·a-1, overall annual yields of products:160429 t·a-1.The influences of operating pressure, temperature and H2/CO in feed gas on reactor's reaction performance were simulated and analyzed. With operating pressure increased, CO conversion and selectivity of alcohols increased significantly. On the contrary, the average gas holdup, superficial gas velocity, static bed height and operating bed height greatly decreased. Meanwhile, the annual yields of C2-4 and alcohols increased slightly while annual yields of liquid hydrocarbons decreased. CO conversion increased significantly with increasing operating temperature, on the contrary, static bed height and operating bed height decreased significantly. Selectivity of C2-4 and alcohols, superficial gas velocity increased slightly while selectivity of liquid hydrocarbon decreased and average gas holdup kept constant. Yields of products increased in varying degrees with increasing temperature. With H2/CO in feed gas increased, CO conversion and selectivity of C2-4 increased significantly, static bed height and operating bed height varied in an opposite way, superficial gas velocity, average gas holdup and selectivity of alcohols almost kept constant while selectivity of liquid hydrocarbons decreased. Yields of products increased with increasing H2/CO.The effects of temperature (100～200℃), pressure drop (0.1～1.4 MPa), filter media pore size (10～30μm) and solid holdup (10%～30%) on filtration rate were investigated. The results showed that the catalyst and liquid products could be separated completely by internal filtration. Affected by pressure drop and filtrate flushing, the decrease of filtration rate gradually slowed down to a stable level while the cake thickness reached dynamic balance with proceeding of filtration process. Meanwhile, the filtration rate increased with increasing temperature, pressure drop, filter media pore size and decreasing solid holdup. Internal filtration rate model was established in a stirred tank reactor based on dimensional analysis, Levenberge-Marquardt algorithm was used for the parameters estimation procedure. Statistical test and relative error analysis revealed that the model was reliable.
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