工业固定床Fe-Cu-K催化剂浆态床F-T合成适应性研究

Investigation on the adaptability of an industrial fixed-bed Fe-Cu-K catalyst to slurry reactor

采用连续搅拌釜式反应器,在接近F-T合成实际工况下考察了工业固定床Fe-Cu-K催化剂浆态床F-T合成反应性能,研究反应温度、压力、原料气空速和氢碳摩尔比等操作参数对催化剂反应活性、产物选择性和稳定性的影响,实验总运转时间达2 500h;同时采用扫描电镜技术(SEM)对催化剂的抗磨损性能进行了研究,结果表明,操作参数对催化剂的活性、选择性和目标产物产率有较大的影响,工业固定床Fe-Cu-K催化剂具有一定的抗磨损性能,F-T合成烃产物分布合理;催化剂具有较高的稳定性,在589h的稳定条件运行内,催化剂的失活速率为0. 23% /d(以CO转化率的降低计);在整个运行期间CH4 选择性维持在较低的水平。

Fundamental study of the reaction performance and stability of an industrial fixed-bed Fe-Cu-K catalyst was carried out by using a continuous stirred tank reactor (CSTR) equipped with a wax removal system under industrial relevant conditions: 255°C - 290°C, 1.5 MPa - 3.1 MPa total pressure, H2/CO (mol ratio) = 0.50 - 1.52 and a space velocity of 1.0 L/gcat·h-1 - 2.5 L/gcat·h-1 (unreduced catalyst base). The effects of reaction conditions on the catalyst activity, product selectivity and stability were investigated. The Scanning electron microscope (SEM) was used to investigate the catalyst attrition resistance. A 2500 h slurry phase reaction result indicated that the changes of the process conditions (temperature, pressure, H2/CO feed ration and space velocity) had strong effects on the productivity and product selectivity. The effects of the adjustment of reaction pressure on the catalyst stability were particular obvious. The deactivation rates of the catalyst decreased with the changes of conditions in the following order: reaction pressure > space velocity > H2/CO feed ratios. The catalyst activity could be enhanced with the reaction temperature increasing, but the selectivity to heavy hydrocarbons was decreased. The increase of the reaction pressure could promote the conversion, and improve the heavy hydrocarbons selectivity and the hydrocarbon productivity. Increasing space velocity in feed gas could increase hydrocarbon productivity, and evidently decline the CO conversion and the selectivity of the heavy hydrocarbons. The increase of the H2/CO feed ratio could raise CO conversion and improve the selectivity of heavy hydrocarbons. The appropriate choice of the F-T reaction parameters in slurry phase could obtain the balance among catalyst activity, hydrocarbon distribution and productivity. The SEM results indicated that the catalyst exhibited robust attrition resistance.