Deodorization Ability And Simulation Of The Three-phase Airlift Loop Bioreactor

Odorous waste gas as a main factor for air pollution has drawn great attentions of many countries worldwide and the emission standard has been set up strictly. Biopurification has become a hot spot for deodorization with the advantages of non-secondary pollution and low cost. Toluene is used as the target agent for odorous gas in this thesis and experiments and transient CFD modeling of toluene waste gas biodegradation by Pseudomonas putida WQ-03 in bubble column and airlift loop bioreactor have been carried out.First, toluene emissions are purified by suspended Pseudomonas putida WQ-03 in a gas-liquid two-phase bubble column and the operational conditions are optimized to meet the Chinese toluene emission standard of 40 mg/m3. A three-dimensional (3D) transient computational fluid dynamic (CFD) model is established to simulate the transient performance of the biodegradation, with the MUSIG model to describe the bubble size distribution, and with mass transfer equations and biomass intrinsic kinetics. The simulation results agree well with the experimental data, such as liquid velocities, toluene removal efficiency and the liquid phase oxygen and toluene concentration. The developed model is used to predict the hydrodynamic properties and the concentrations of the components of each phase, as well as the discussion of the rate-limiting step for the biodegradation process.Secondly, toluene waste gas is treated by suspended P. WQ-03 in a two-phase internal airlift loop reactor and a 3D transient CFD model is established to simulate the dynamic performance of the biopurification, with the MUSIG model, mass transfer equations and biomass intrinsic kinetics. The model has been verified by the experimental data of liquid velocities, toluene removal efficiency and the liquid phase toluene concentration. The developed model can be used to predict the hydrodynamic properties and the concentrations of the components of each phase. The rate-limiting step in the biopurification is also discussed.Thirdly, toluene waste gas is purified by immobilized P. WQ-03 in a three-phase bubble column reactor and a 3D transient CFD model is established to simulate the dynamic performance of the biopurification, with the MUSIG model, mass transfer equations and biomass intrinsic kinetics. The model has been verified by the experimental data of liquid velocities, toluene removal efficiency and the liquid phase toluene concentration. The developed model can be used to predict the hydrodynamic properties and the component concentrations of each phase, as well as the rate-limiting step which is the optimized simulation based on.Finally, toluene waste gas is purified by immoblized P. WQ-03 in a three-phase internal airlift loop reactor and a 3D transient CFD model is established to simulate the dynamic performance of the bio-purification, with the MUSIG model, mass transfer equations and biomass intrinsic kinetics. The model has been verified by the experimental data of liquid velocities, toluene removal efficiency and the liquid phase toluene concentration. The developed model can be used to predict the hydrodynamic properties and the component concentrations of each phase. The rate-limiting step is also discussed based on which optimized simulation is carried out.