Experimental study and numerical simulation on flow field of venturi scrubber purifying biomass gas

In order to settle the problem of tar droplets from biomass gasification gas by venturi scrubber, CFD software Fluent was employed to simulate the internal flow field in venturi tube. The static pressure field and axial velocity field inside venturi tube were obtained, and the variation of internal flow field was analyzed from the perspective of energy conversion. The results indicated that the pressure of throat pipe dropped significantly, and the static pressure energy was converted into kinetic energy so as to create larger turbulence, which improved purification efficiency. The total pressure drop and purification decoking efficiency of venturi scrubber were experimentally studied. The test results of total pressure drop of venturi scrubber were compared with simulated data, which showed that the test results matched well with simulation results when throat flow speed was between 70 and 120 m/s. The decoking efficiency could be effectively estimated using empirical formula based on the actual total pressure drop of venturi scrubber. Besides, the test data showed that decoking efficiency could reach to above 90% when throat speed was over 90 m/s and liquid-gas ratio was over 2 L/m3. The research laid a foundation for the application and expansion of venturi scrubber purifying biomass gas.