Study On DeNO_x Combustion Of Gas Turbine And Simulation On Flue Gas DeNO_x Of HRSG

With the development of the electric power industry,the style of gas-steam combined with cycle power generation which used natural gas as fuel,gas turbine as integral part,has become more and more popular.And gas turbine is developing toward the direction of high parameters,high efficiency and low emission,and the emission of nitrogen and oxygen compounds is always one of the key issues.The policy level is becoming more and more stringent,and the gas steam combined cycle power plant,which uses natural gas as fuel,will face a huge challenge to reduce the emission of nitrogen and oxygen compounds.Because of the increasing stringent emission limits of NOx on gas turbine,combustion fluctuation caused by diversity nature gas,it is necessary to carry out targeted research on the low nitrogen gas pre mixing combustion method and steam boiler flue gas denitration.In this paper,CFD numerical simulation software FLUENT was used to simulate the combustion process of F-type gas turbine combustor in a combined cycle power plant.Based on the comparison with the actual operation data,the combustion characteristics of combustor inlet fuel premixed water vapor were analyzed.And the chemical kinetics of the process was studied by the CHEMKIN software package.We use ASPEN PLUS for process calculation of the gas waste heat boiler with new flue gas denitration reactor of SCR,and analyzed the features related to the gas waste heat boiler with flue gas denitration in whole operating conditions.Finally,we use the analysis way of stacking method in variable condition features of gas turbine to study how the draft resisitance influenced the gas turbine's performance.Results indicate that existing experimental data and running data verifies reasonability of the model on the load rate of 40%?60%?100%.From the axial combustion cylinder,the flue gas temperature is up to 1841 K,gas pressure loss is about 0.22MPa;the concentration of NO keep the same pace of the variation of temperature,and thermal NO is the main NO_x,near the duty nozzle,temperature is up to about 1900K;and near the main combustion nozzle,the temperature is up to about 1200 K,outlet velocity is up to 140m/s;The NOx is main distribute near the duty nozzle,In the transition section of the combustion chamber,the NO concentration on 40%,60%,100% load rate is about 55.88 ppm,42.04 ppm,18.62 ppm.Study on combustion and emission characteristics of the fuel steam pre-mixing with water vapor show that fuel premixed ratio increases,the flue gas velocity decreased,the flue gas temperature decreases,the average concentration of outlet NO decreases.Acroding the calculation of the CHEMKIN,the flame zone is the mian district of producting NO_x,and mainly for thermal NO,pre mixed with steam can greatly reduce the amount of NO generated in the fuel,but also bring the gas velocity affected by the flame length,variable length,combustion efficiency and small adverse results;NO reduced is mainly due to water vapor fuel under high pressure and temperature in the combustion of O,H and OH in the atmosphere of free radical concentration increased significantly,which makes the basic chemical reaction rate of the chain reaction in the NO toward the direction of change to inhibit the production of NO.The study of the SCR of HRSG under full condition in gas-stream combined cycle power,shows that the waste heat boiler of SCR DeNOx reactor can reduce the NO_x emission concentration less than 30mg/Nm~3,which boiler is lack of flue gas heating measures,and the NOx emissions can adapt to the new requirement;Unit is at low load rate,while outlet NO_x of waste heat boiler is high,the exhaust gas temperature and different on-off cycles within the NO_x concentration fluctuations restricted the denitration efficiency.According to the NO_x concentration boundary curve,HRSG can jugde whether more measures is needed to the new external combustion system,such as flue gas heating and other measures.Studying on the 20%,40%,75%,and 100% load rate,increasing new SCR system,flue gas resistance time increases,which makes the power output and the thermal efficiency of the host variable decreased to some extent,to change the characteristics of exhaust gas,and reduce exhaust pressure,compressor and turbine exhaust temperature increased.