| The gas-liquid two-phase flow in the water scrubbing-cooling chamber (WSCC) of gasifier was mainly researched in the thesis. The experimental studies of the structure optimization of compartmentation board and dip tube were carried out. At the same time, a two-dimensional numerical simulation was performed to study falling water film flow field and heat and mass transfer in two different industrial-scale dip tubes of WSCC of OMB entrained-flow gasifier.The characteristic parameters of gas-liquid two-phase flow were measured during experiment by a parallel-wire conductance probe. Based on gas holdup, bubble diameter and surface concentration, the structure of the compartmentation board was optimized. The vibration of dip tube was estimated by a waterproof acceleration sensor of LC0120T type under different conditions. The comparison of vibration energy level and frequency spectrum were discussed in detail. No-branches dip tube was proposed to adopt under higher gas velocities after researching the vibration of dip tube and the characteristic parameters of the gas-liquid two-phase flow in the WSCC.The predicted axial temperature distribution results were in good agreement with the experimental data measured in the bench-scale dip tube, which validated that the numerical models, including VOF method, standardκ-εturbulent model, mass transfer equations and all the other models applied in this paper were reasonable. The simulation results of 4 m dip tube indicated that the thickness of inlet water falling film, the velocity of inlet quenching water and the inlet velocity of syngas had a great influence on the heat and mass transfer and the flow patterns of the water falling film of industrial-scale dip tube. Furthermore, the results of 6.55 m dip tube revealed that the temperature of the syngas achived 659K at outlet of the dip tube. When the length of the dip tube was shortened to 2 m, the corresponding temperature was 942K and the volume of water steam was 49%. |
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