Design And Performance Research Of SCR System For Diesel Generator

Diesel generator sets are increasingly used as backup power sources in various locations,but the content of nitrogen oxides in the exhaust gas far exceeds the national emission standard limits.SCR(selective catalytic reduction)after-treatment technology is the main technical route to reduce nitrogen oxides in the exhaust of diesel generator sets.This article takes Cummins C1400D5 diesel generator sets as the object to reduce the emissions of diesel generator sets which match SCR system.This article analyzes the principle of the SCR system of the diesel generator set.In the urea injection system,SCR carrier,and SCR catalyst,this paper takes the overall design of the SCR system for the Cummins C1400D5 diesel generator set,and the performance evaluation index of the SCR system was expounded.The SCR catalytic converter is a key component of the SCR system of the diesel generator set.This article initially designs its specific structure based on the displacement characteristics of the C1400D5 diesel generator set.The three-dimensional model of the SCR catalytic converter was established on the ANSYS workbench platform and meshed.The computational fluid dynamics software Fluent was used to simulate the internal flow field of the SCR catalytic converter to simulate the distribution of its internal velocity field and pressure field.This paper established the calculation model of the SCR catalytic converter under different structural parameters on the workbench platform of ANSYS,and using Fluent software simulated the models,to research the structural parameters(expansion tube angle,contraction tube angle,carrier length,carrier gap,whether to install The deflector)affects the gas flow law inside the catalytic converter.Based on the Nelder-Mead algorithm,the structure of the SCR catalytic converter is optimized from the four factors such as the expansion tube angle,the contraction tube angle,the carrier length,and the gap between the carriers,and a set of optimal structural parameters for the SCR catalytic conversion is obtained.The gas flow uniformity index of the front end of the device and the carrier respectively exceeded 88%.This paper test the SCR system emission reduction which matches the Cummins C1400D5 diesel generator set.Combined with the installation characteristics of the SCR system of the diesel generator set,it was studied to install thermal insulation cotton on the exhaust tail pipe of the diesel generator set,install the deflector at the front bend of the SCR system,shorten the length of the urea injection pipe,and change the layout of the SCR catalytic converter The impact of these four test schemes on conversion efficiency.The results show that four programs are all it is beneficial to improve the conversion efficiency of the SCR system of the diesel generating set.The test results show that after the diesel generator set is equipped with an SCR system,the NOx of the diesel generator set drops significantly under various operating conditions,which can meet the national emission standards.