Study On Gas Presure Drop Of Rotating Zigzag Bed And Its Flow Field Simulation

Following the appearance of RPB (Rotating Packed Bed), Rotating Zigzag Bed (RZB) appears as a novel kind of highly efficient mass transfer equipment in which gas-liquid mass transfer process was greatly intensified. RZB can be widely used as the equipment of distillation, absorption and mass transfer controlled chemical reaction in the chemical industry, petrochemical industry, pharmacy and light industry. The rotor with the combination of static disc and rotating disc spares the seal which was fixed between rotor and gas outlet, this kind of rotor structure makes it easy to feed in the rotor and plural rotors can be fixed in series on the same shaft in the shell. RZB has the specific zigzag passages which improve the mass transfer efficiency by greatly increasing the interphase area, and it also effectually make the liquid have well initial distribution. These make RZB have a reasonable gas flow space in the rotor.Gas pressure drop is an important property for the performance of the equipment. This paper studied gas pressure drop of RZB with the air-water system and established the model of dry bed gas pressure drop. The relationship between gas pressure drop and the rotor structure of RZB at different operation conditions was investigated, and the model of dry bed gas pressure drop in the RZB was founded. Fluent was used to simulate the flow field of RZB, and the path of gas movement was analyzed. The conclusions as follows,(1) Gas pressure drop of dry bed increases with the increase of gas flow rate, and it decreases with the clearance between the immobile disc and the rotating disc. Gas pressure drop of the rotor decreased with the increases of the clearance between the immobile disc and the rotating disc, total pressure drop changes little when the clearance increases to some magnitude.(2) Gas pressure drop of irrigated bed increases with the increase of gas flow rate, and the influence of gas flow rate on pressure drop become weaker with the increase of clearance between the immobile disc and the rotating disc. Gas pressure drop of irrigated bed is decreasing firstly and then increasing with the increase of gas flow rate.(3) There is an optimal height for the rotor of RZB, the optimal magnitude is 90 mm for RZB used in the experiments.(4) The reasonableness of the equal flow-through area principle which was adopted in the design of RZB for the experiments was proved by the experimental results. Gas pressure drop of the rotor is made up of friction resistance, body resistance and centrifugal resistance. Using the dry gas pressure drop model proposed, the calculated results agree well with the experimental results, and the model proposed lays the foundation for the establishment of the irrigated gas pressure drop model.(5) CFD software Fluent was used to simulate the flow field of dry bed in RZB. RNG k-εturbulent model and SIMPLE arithmetic were used. The simulation results demonstrate the path of gas movement in RZB.(6) The simulation results indicate that gas rapidly fulfills the clearance between the rotor and shell after gas got into the RZB, then gas get into the rotor along radial direction. The path of gas movement in the rotor is mainly influenced by the baffle obstructed the gas progress. Gas form extensively vortex at the outlet of the rotor. The simulation results are better than the model in the chapter two, and they agree well with the experimental results.