Gas-liquid mass transfer and reaction characteristics of gas-liquid-solid circulating micro-fluidized bed

Gas-liquid-solid circulating micro-fluidized bed represents a novel subfield within the realm of micro-fluidized beds, but fundamental research in this area remains insufficient. This paper investigated the impact of operating conditions and modes on the volumetric mass transfer coefficient (AK) in a circulating micro-fluidized bed with a riser diameter of 4 mm. Additionally, the adaptability of circulating micro-fluidized bed reactor for the gas-phase oligomerization of isobutylene under atmospheric pressure was assessed. The results show that with the increase of circulation rate of solid particle, the interphase mixing between particles and bubbles in the riser is strengthened, thus reducing the gas-liquid mass transfer resistance. Proper addition of solid particles can increase the mass transfer coefficient by 2 times. Compared with the micro-expanded bed, the advantage of the circulating micro-fluidized bed is that it can handle the gas-liquid mass transfer process under the condition of high superficial gas velocity, and its AK is 1.13 similar to 1.82 times that of the micro-expanded bed. Under 65 degrees C and atmospheric pressure, the oligomerized products of isobutylene in circulating micro-fluidized bed with molecular sieve as catalyst are mainly triisobutylene.