Abstract: Industrial application of slurry bed F-T synthesis technology is limited by separation of fine particles in high solid holdup slurry. An airlift external-loop slurry reactor coupling with membrane separation was created to develop cross-flow microfiltration technology based on special hydrodynamic properties and three phase distribution characteristics. Cross-flow microfiltration performance of nitrogen, diesel and Co catalyst model system in an airlift external-loop slurry reactor was studied, influence of gas superficial velocity u_g, solid holdup r_s and transmembrane pressure difference ΔP were investigated. It was found that when ΔP was 0.45 MPa, u_g was 0.1 m/s and r_s were 10% and 20%, the stable permeate flux were 60 L/(m².h) and 17 L/(m².h) , respectively, and the particle concentration of permeate was less than 5 mg/L, the filter could run stably at least 720 min. The influence on recovering membrane flux of plused backflushing technology and single continuous backflushing technology was compared. The results showed that the former was more suitable to recover membrane flux.

Key words: external-loop slurry reactor, liquid solid separation, cross-flow microfiltration, backwashing