Abstract: A 500 t/d grate furnace of a domestic waste incineration power plant in Lhasa was taken as the research object， FLIC and ANSYS FLUENT software were respectively used to simulate the bed solid-phase combustion process and furnace gas-phase component combustion process under low pressure conditions. The numerical simulation results were compared with the monitoring data of the power plant， and the simulation results were in good agreement with the test data. After verifying the correctness of the combustion simulation method， the orthogonal test method was adopted to carry out the optimization simulation research on the air distribution of the waste incinerator. Through variance analysis， the operating conditions of the boiler under the optimal working conditions were predicted， and the main and secondary factors affected the boiler operation were determined to be the distribution ratio of primary and secondary air volume， and the distribution of primary air volume and the supply air temperature， respectively. When the furnace temperature did not meet the requirements in low pressure environment， it was provided that the ratio of primary and secondary air volume and the ratio of primary air volume could be preferentially adjusted. On the premise of satisfying the secondary combustion and the disturbance to the flue gas in the combustion chamber， the secondary air volume could be appropriately reduced to improve the flue gas temperature level in the combustion chamber.

Key words: low atmospheric pressure, waste incineration, operation optimization, numerical simulation