| The adsorption tower is the main equipment for gas purification and separation.It is the key to improve the adsorption efficiency of the gas passing through the adsorption tower uniformly.Therefore it is significant to investigate the uniformity problem for gas distribution in the adsorption tower.During the two years of professional master's career,this study mainly aims at the waste and filtration failure problems caused by the existing exhaust gas accumulates through the middle part of the filter during the actual operation process of the adsorption tower device produced by an environmental protection company for the first year.The numerical simulation optimization study of the intake structure of the adsorption tower was carried out in this dissertation.Firstly,three intake structures of the inflow gas with or without the punched baffle are considered in two-dimensional model on condition that the inlet diameter is 0.42 m and the outlet diameter is 0.27 m.That is,the side intake two-way cross flow model without the punched baffle,the low air intake two-way cross flow model without or with the punched baffle.The obtained results can be summarized as follows:(1)In the low air intake two-way cross flow model without punched baffle,the pressure distribution in the inlet chamber is relatively uniform.The pressure difference is 31 pa.The speed distribution becomes relatively uniform when the gas passes through the filler,but the speed of the gas decreases obviously.(2)For the side intake two-way cross flow model without the punched baffle(The air enters into the equipment from two sides and the inlet diameter is0.42 m.The intake air volume is significantly increased and the air output is unchanged),Compared with the low air intake two-way cross flow model without punched baffle,the internal total pressure distribution is obviously higher in the side intake two-way cross flow model without the punched baffle,which is about 28000 pa.The gas has a large vortex at the inlet pipe diameter transition,and the flow velocity distribution is poor.(3)The lower intake air two-way cross flow type is provided with the perforated baffle adsorption tower,the pressure is larger than the same air intake position without the perforated baffle.The overall pressure is about 8000 pa,the intake cavity is about 9000 pa.But the pressure from the lower intake air is smaller than the side air intake without theperforated baffle.The overall pressure is about 20,000 pa,and the intake cavity is about21,000 pa.The pressure distribution in the inlet chamber is smaller on the lower side than that on the upper side and the pressure difference is about 60 pa.In the low air intake two-way cross flow model with punched baffle,the distribution of gas at the filler is relatively uniform with respect to the other two models.Then,the three-dimensional numerical simulation is carried out on the low air intake two-way cross flow model without or with the punched baffle,respectively on condition that the inlet diameter is0.42 m and the outlet diameter is 0.42 m.The main results are given in the following:(1)The overall pressure and the intake chamber pressure in the low air intake two-way cross flow model with the punched baffle are larger than that without the punched baffle(the difference is about 1200 pa and 1300 pa,respectively).(2)Compared with the low air intake two-way cross flow model without the punched baffle,the airflow distribution of the filler is more uniform at the orifice and the fluidity of the gas is enhanced.Finally,the three-dimensional numerical simulation on the low air intake two-way cross flow model with the punched baffle is investigated from three aspects.That is,the height of filler(1.0m and 1.3 m),the porosity(0.35 and 0.4)and the diffusion coefficient(0.00027,0.0003 and 0.00035).The corresponding results are obtained as below:(1)Compared with the model with theheight1.3 m of filler,the gas velocity with the height 1.0 m of filler is slightly larger than 0.2-0.3 m/s and the overall pressure and the intake chamber pressure difference are 1800 pa and 1400 pa,respectively.However,the height of filler has no influence on the uniformity of gas distribution and the overall pressure distribution in the adsorption tower.(2)The size of the porosity and the diffusion coefficient is inversely proportional to the pressure values of various parts in the adsorption tower.These results obtained in this study can assist in the optimization of absorption tower,increasing its recovery efficiency of exhaust gas,reducing the equipment and operation cost. |
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