Study On Design Of Marine SCR System Catalytic Converter Structure

As the NOx emission limits TIER II of MARPOL Convention have come into effect, a highly efficient diesel emission after-treatment technology- Selective Catal-ytic Reduction (SCR)- attracts more and more attention of people. This thesis aims at how the changes of related parameters during the designing of catalytic converter will affect the flow of exhaust in it.on the basis of a deep understanding about SCR system’s working principle and process, the thesis introduced the system comprehensively; designed the catalytic con-verter for a specific type diesel and established its three-dimensional models; simulat-ed the models with the FLUENT software, analyzed the simulation results and provi-ded suggestions on the designing of catalytic converter of SCR system, the key points of this thesis are design and simulation of catalytic converter, including:(1)the design of dimension of catalyst according the running parameters of a spe-cific type diesel;(2)established the three-dimensional models and simulated them at the inlet(out-let) expansion(contraction) tube angle of 90°,75°,60°,45°,30°espectively, analyzed the effect of the inlet(outlet) expansion(contraction) tube angle to the flow field of catalytic converter on velocity distribution, turbulence intensity, vortex intensity and pressure drop between inlet and outlet;(3)when the inlet(outlet) expansion(contraction) tube angle is 30°, established the three-dimensional models and simulated them at the distance between catalyst en-dface and catalyst area shell endface of 0mm,50mm,100mm,150mm,200mm respe-ctively, analyzed the effect of the distance between catalyst endface and catalyst area shell endface to the flow field of catalytic converter on velocity distribution, turbulen-ce intensity, vortex intensity and pressure drop between inlet and outlet;(4)provided the recommended values of design of SCR system catalytic convert-er according to the results of analyses.