Numerical simulation of influence of SCR denitration reactor on furnace implosion

Numerical simulation of 300 MW pulverized coal boiler, including furnace, super-heater, economizer, SCR denitration reactor air pre-heater and EPS, was conducted. Exchanger model was used as heat exchanging process in the flue duct, and heat-exchanging efficiency was defined by NTU methods. ID fan was regarded as a thin wall with its operation characteristics defined by a simplified function. The simulation result agrees well with the designed value. Then dynamic simulation was conducted on systems with and without SCR denitration reactor, respectively. Based on the results, it is pointed out that implosion results from the combined factors, among which are increasing of ID fan head, decreasing of flue gas mass flow rate, disappearing of inlet air and diminishing of gas formation. Implosion pressure increases by only about 1 kPa after installation of SCR denitration reactor, since ID fan only accounts partly for furnace low pressure. Such results can remove the uncertainly about whether SCR denitration reactor will lead to increased furnace implosion.