Bioler Operation Performance And Pollutant Emission Characteristics Analysis Of Biomass Gas Co-firing With Coal

Biomass gas co-firing with coal can utilize efficiently biomass and reduce pollutants emission by replacing part of coal,and it is beneficial to the boiler combustion and operation.The paper takes a 300 MW coal-fired boiler as the research platform to study the pollutant emission characteristics and the boiler's performance of biomass gas co-firing with coal based on a process simulation software Aspen Plus.The main research content and conclusion are as follows:?1?The biomass gasification model is established by Aspen Plus to study the biomass gasification process,and then the best air-fuel ratio is determined.Pine with higher low calorific value is selected as gasification fuel.With the air-fuel ratio increasing,the volume fraction of H2,CH4 and CO₂ are all reduced,CO increases first and then decreases contrary to H2 O,but N2 increases.The gasification gas heating value and gasification efficiency show a trend of decreasing after first increasing with the increase of the air-fuel ratio,and both reach their highest values under a certain ratio,which is the best air-fuel ratio.?2?The model of biomass gas co-firing with coal is established based on Aspen Plus,to simulate the co-firing process.The syngas that pines with 10%,20% and 30% moisture content are gasified at their own best gasification conditions are sent to the boiler to co-fire with coal.The highest combustion temperature drops gradually with the increase of biomass moisture content and co-firing ratio.The flue gas volume and flue gas temperature increase with the increase of moisture content,but the boiler efficiency drops?3?The influences of coal quality and co-firing ratio on the pollutants emission characteristics and boiler operation performance are studied under the conditions of three kinds of different quality bituminous coal respectively co-firing with 20% moisture content pine gasification syngas.The highest combustion temperature under different co-firing conditions drops with the decrease of coal quality and the increase of co-firing ratio.With the decrease of coal quality,the pollutant NO_x reduces and SO₂ increases,but both reduce with the increase of co-firing ratio.The flue gas volume of high quality coal co-firing is the maximum,the flue gas temperature is the highest,the boiler efficiency is lowest,but the boiler efficiency after inferior coal co-firing is highest.?4?The CO₂ emission reduction,the NO_x ?SO₂ emission concentration and emission reduction rate of pure coal combustion and co-firing are calculated and analyzed,to verify the conclusion that biomass energy is a kind of clean energy,and the co-firing of biomass gas andcoal can save coal consumption and reduce the pollutant emission.