The Development And Research On Influence Factors Of Photocatalytic Pilot-scale Reactor For Purifying VOCs

In order to overcome the problems of the present photocatalytic reactors,such as low efficiency of mass transfer and light distribution,uneven distribution and hard to scale up,a new photocatalytic reactor was designed in this paper.A bench-scale envalution was conducted before the pilot experiment and a photocatalytic reactor of dealing volatile organic compounds(VOCs)was built.The performance of photocatalytic reactor was optimized and tested with toluene as removal object.The research can be mainly included as following:In the bench-scale evaluation of the photocatalytic reactor of purifying VOCs,the impacts of treatment of grid on the loss rate of catalysts,surface appearance adsorbability and photocatalysis activity were evaluated.The results showed that the grid which was pretreated and dried after spraying catalysts was the best.The impacts of initial concentration,relative humidity,pieces of catalysts and the catalyst life time on the removal of toluene were evaluated.On the condition of toluene initial concentration of 5ppm,relative humidity of 75% and 20 pieces of catalysts,the best removal efficiency and mineralization rate were 96.6% and 68.8%,respectively.The removal efficiency and mineralization rate were evaluated after 8hour.A high mass photocatalytic reactor was designed and produced.The change of grid groove angle rotary impact on mass transfer was evaluated.The high mass-transfer photocatalytic reactor can obviously change the flow distribution and improve the efficiency of mass transfer,which provided the theoretical support for the pilot-scale photocatalytic reactor.In the design and production of the photocatalytic reactor of purifying VOCs,the photocatalytic reactor consisted grids,slots,light strips and light strip frame and included 140 light strips and 20 grids for installation,which can be arranged at different angles to improve the mass transfer.16 lamp beads were placed in each lamp.And 10 lamp plates were in the reactor,which fixed 7 double-faced lamps.The light was mutually staggered for light distribution.In the test and optimization of the photocatalytic reactor,a series of control experiments were conducted.And the photocatalytic reactor was optimized with the internal module structure(the number of grids,the total spiral angle and the layout of lamp),the influence of reaction conditions and the catalyst life time.The optimum conditions of the photocatalytic reactor were as follows: 16 grids for installation with the total spiral angle of 180 degrees,all light opened,the humidity of 70%,the initial toluene concentration of 10 ppm.The best removal efficiency and mineralization rate were 21.9% and 10.7%,respectively.And the toluene removalefficiency and mineralization rate were evaluated for 168 h.The removal efficiency and mineralization rate were 7.6% and 4.3%,respectively.After the catalyst regeneration of 8 h,the removal efficiency and mineralization rate were 8% and 5%,respectively.