DEVELOPMENT OF ANEW FLUID-BED CATALYTIC REACTOR TO PRODUCE LIQUID FUELS FOR THE NEXT GENERATION

以氢气和一氧化碳为原料，采用气相流态化技术合成轻烃燃料。这是因为反应热很容易被带走，反应温度可以在反应器中保持恒温。然而，由于反应涉及到床内气体体积的减少，流态化质量急剧下降。当气体体积减小程度较大时，气泡提供的气体不能补偿乳化相的体积减小。因此，乳状液相的空隙率减小，乳状液相流动性的降低会干扰气泡的上升。最后，床内发生脱流作用。在这种情况下，反应堆不能安全运行。本研究对保持良好流态化质量的反应条件进行了研究。在实验中，以氢和二氧化碳为模型反应，在镍催化剂上进行了甲烷合成反应。根据气体体积减少率和气体体积比，得到了稳定运行的判据。结果表明，当L/S的体积缩小率大于0.01时，最大体积比小于0.9时，不能建立稳定运行。此外，还研究了内件对提高流态化质量的影响。筛子的开孔面积分数为0.70。当使用一块网板时，通过打破产生的脱流部分而不是通过打破产生的脱流部分，可以有效地防止脱流部分的产生。因此，当金属网安装在布料器上方10~20 cm处，网间距为10~20 cm时，可获得良好的流态化效果。

Gas phase fluidized beds have been used for the synthesis of light hydrocarbon fuels from hydrogen and carbon monoxide. This is because that reaction heat can be easily removed and reaction temperature can be kept at a constant temperature in the reactor. However, the fluidization quality drastically decreased for the reaction involving a decrease in gas volume in the fluid bed. When the degree of the gas volume decrease is large, the gas supply from bubbles cannot compensate the volume decrease in the emulsion phase. Consequently, the voidage of the emulsion phase reduces and the decrease in the fluidity of the emulsion phase disturbs bubbles to rise. Finally, defluidization in the bed occurs. The reactor cannot be operated safely at these conditions. In the present study, the reaction conditions to keep the good fluidization quality were investigated. In the experiments, methane synthesis from hydrogen and carbon dioxide as a model reaction was carried out over Ni catalysts. The criterion for the stable operation was obtained based on the gas volume reduction rate and the ratio of gas volume. It was shown that the stable operation could not be established when the volume reduction rate was over 0.01 l/s and maximum volume ratio was below 0.9. In addition, the effects of internals were studied to improve the fluidization quality. The fractional open area of the sieve was 0.70. When one mesh plate was used, it is effective to prevent the generation of the defluidized part by breaking the generating defluidized part rather than by breaking the generated defluidized part. Therefore, the good fluidization could be established when the metal meshes were installed at 10-20 cm above the distributor and the intervals between the meshes were 10-20 cm.