Experimental investigation the influence of mixed air and particle flow characteristic on pulverized coal combustion

In order to study the effect of mixed air and particle flow characteristic on pulverized coal combustion,a reverse-jet swirl burner with cone pre-combustion chamber is selected as investigation objection,the 14 MW pulverized coal combustion experimental system is used to research combustion characteristic with reverse-jet and jet flow.On the basic of high temperature thermocouple,flue gas analyzer and high speed camera measurement methods,the dates of temperature,species volume concentration and flame shape scale are obtained.Then,combining with pulverized coal combustion basic theory,the combustion process of different regions are discussed to reveal the difference of reverse-jet and jet flow on pulverized coal combustion characteristic.The experimental results show that the stable and low nitrogen combustion can be achieved in pre-combustion chamber both reverse-jet and jet flow,and high temperature corrosion and slagging are avoided.But the difference of them are combustion fraction in pre-combustion chamber and flame scale beyond pre-combustion chamber outlet.In pre-combustion chamber,the maximum temperature is 1 255 ℃ and O2 decaying rate is 0.139%/mm for reverse jet case,ring reduction atmosphere zone is formed and CO volume concentration more than 50 000×10-6,indicating that the combustion fraction is larger.The maximum temperature is 1 096 ℃ and O2 decaying rates are 0.135%/mm and 0.080%/mm in upstream and downstream respectively for jet case,central reduction atmosphere zone is formed and CO volume concentration more than 50 000×10-6,indicating that the combustion fraction is smaller.Beyond pre-combustion chamber outlet,the flame shape is bright and tubby for reverse-jet case,and flame length is 2 697 mm,diameter and divergence angle is 760 mm and 24.11°,indicating that the combustion process is shorter.The flame shape is slender and slightly low brightness for jet case,and flame length is 5 747 mm,diameter and divergence angle is 536 mm and 7.81°,indicating that the combustion process is longer.