Marine Diesel Engine SCR Denitration System Technology Research And Numerical Simulation

The denitrification performance of Marine diesel engine exhaust in real smoke environment is very different.According to the different flue structure of the diesel engine SCR system,Fluent software is used to simulate the fluidity of each guide plate layout scheme.The spray atomization process of the simulated nozzles,the injector is compared with the two,and the correctness of the test scheme is verified.Studies are carried out through the following aspects:In order to study the flow changes of SCR catalytic converters in flue,the SCR system structure was simplified.The design of the structure of the second corner of the flue and the layout of the guide plate are designed,and the layout and quantity of the six guide plates are designed respectively.From the velocity field,the pressure loss,and the experimental comparison,the diversion function of the guide plate is simulated,in order to determine the best scheme of the guide plate layout in the flue.After that,use the different size of the guide plate to continue the simulation.The experiment and simulation prove that the drainage effect is the best when the five pieces of the same guide plate are arranged in the inclined flue.Similarly,in the arc type flue,it is the best to place three variable arc length deflectors on the gas drainage and reduce the pressure loss.This shows that in the flue,the guide plate can not only guide the flow of mixed gas,reduce the high speed zone and low speed zone,but also reduce the pressure loss of the system.Under the simulation of different gas volume,the flow of the scheme of each guide plate is arranged,and the optimal scheme of the corresponding guide plate structure is obtained,and the test and verification are carried out.Simulation and experimental results show that the smoke volume is 43490 kg/h,the inclined guide plate type flue four variable arc length respectively layout scheme and circular arc flue four arc length guide plate column layout plan drainage effect is best;When the smoke volume is 61570kg/h,it is the best to arrange the layout of the five variable arc length guide plates in the inclined flue and the four variable arc length guide plates in the curved flue.When the smoke volume is 102733kg/h,the scheme of the three-piece variable arc length guide plate in the inclined type flue and the five-block variable arc length guide plate in the arc type flue are the best.The influence of spray atomization process,gas mixture uniformity and other factors on the spray atomization result was simulated by the establishment of a suitable geometrical model of nozzle and injector.The results show that the spray is better in atomization and the experiment is carried out.The denitration rate of the SCR system is calculated,and the four diesel engine flue gas flow schemes can meet the emission requirements.