The Design And Optimization Of Flue Gas Denitrification Process In Atmospheric And Vacuum Distillation Unit

Since the development of the world,air pollution problems have troubled people along,such as greenhouse effect,acid rain and ozone layer destruction.The main factor is nitrogen oxide(NO_X).NO_X mainly exists in the exhaust gas produced by fuel combustion in industrial production.When realizing the great harm that NO_X brings to the earth,the country has formulated increasingly stringent emission standards for refining and chemical companies.How to efficiently reduce nitrogen oxide emissions has become the main research goal of the company.In the 10 million tons/year atmospheric and vacuum distillation unit of a petroleum refining enterprise,the nitrogen oxide in the flue gas produced by the atmospheric and vacuum furnace is about 200-400 mg/m~3.It exceeds the new national standard which is about 100 mg/m~3.This paper designs and optimizes the denitration system of the heating furnace in the atmospheric and vacuum distillation unit.According to the actual working conditions of the atmospheric and vacuum furnace,this paper analyzes the process of flue gas denitration and compares the advantages and disadvantages of various denitration technologies.Finally,it chooses the selective catalytic reduction(SCR)method to denitrify the nitrogen oxide from the flue gas.The honeycomb Ti-W-V catalyst is selected as the denitrification catalyst.In this paper,the SCR denitration kinetic model,transfer model and reactor model are established.And it uses Aspen software to simulate the denitration process.The paper calculate the main process equipment and determined the appropriate equipment structure and operating condition.The results show that this device can meet the national emission requirements for NO_X<100 mg/m~3.This paper also studies the structure of the flue gas denitration reaction system.It uses computational fluid dynamics(CFD)simulation software to optimize the baffle of the reactor part and simulate the flow field before and after the optimization.This paper uses CFD software to model and mesh the SCR reactor and optimizes the design of the baffle.The optimized diversion device is simulated and verified through the distribution of velocity field and concentration field.After optimization,the distribution of flue gas through the flue is more uniform.Most of the flue gas can enter from the center of the reactor.It makes the reaction more sufficient.