Charge Performance And Electric Field Characteristic Studies Of Biomass/coal Co-firing Ash

Fly ash particles charged by the electric precipitator is the premise and the basic process of capture.Volt-ampere characteristics and plate current density distribution are the key parameters to measure the electric field characteristics and wire-plate matching model of electric precipitator.Biomass and coal mixed combustion,because of the differences in the physical and chemical properties of biomass and coal and the combustion characteristics,may make the co-combustion ash in the electric precipitator inside the charge performance and the electric field characteristics of a certain change to affect the capture efficiency.So it is very important to study the characteristics of charge performance,the volt-ampere characteristics and the plate current density distribution of co-combustion ash.In this paper,the common corn stalk biomass fuel,peanut shells,wood chip were mixed with anthracite and bituminous coal in the proportions of 0,5%,10%,15%,20%and 100% of the total calories,respectively,and then made into a series of co-combustion ash.Through the use of self-designed the system of total electric charge measurement and the grading charge-mass ratio measurement system,the total and graded charge-mass ratio of the co-combustion ash was measured under the condition of 5kV DC positive pressure.The experimental results show that the charge-mass ratio of co-combustion ash increases with the increase of biomass ratio,the higher the blending ratio,the stronger the charge characteristics of the co-combustion ash.In addition,the mixing biomass species have a certain influence on charge performance of the co-combustion ash,corn stalks,peanut shells and wood chips,and the charge characteristics of corn stalk were the strongest,followed by peanut shells and wood chips.At the same time,the mixed coal also has a certain influence on the charge characteristics of the co-combustion ash.It is concluded that the charge characteristics of co-combustion ash are related to its chemical composition,micro-morphology,specific resistance and so on.On the level of electric field characteristic,the volt-ampere characteristics of co-combustion ash were determined by simulating the corona discharge of the electrostatic precipitator on a self-designed horizontal electric field volt-ampere measurement device.The results show that the mixing ratio of biomass has a significant effect on the volt-ampere characteristic of co-combustion ash.With the increase of theblending ratio of biomass,the volt-ampere characteristic of co-combustion ash is better.Corn stalks,peanut shells,wood chips,the volt-ampere characteristic superiority of three kinds of co-combustion ash: corn stalks>peanut shells>wood chips of co-combustion,and with the increase of the biomass ratio,the effect of the mixed biomass on the volt-ampere characteristics of the co-combustion ash becomes more and more obvious.The results also show that the volt-ampere characteristics of co-combustion ash of biomass and anthracite are obviously better than those of bituminous coal,then there are differences between the different types of anthracite,but the difference is small.By using the grid type micro current signal in self-designed plate current density distribution measurement device,plate current density distribution of co-combustion ash were investigated,the results show that the biomass ratio and the blended biomass only have an effect on the current density and have no effect on the uniformity of the current density distribution.In addition,the corona line type is an important factor affecting the current density distribution characteristic of the co-combustion ash.Therefore,it is very important to choose the best form of pole-matching for the efficient capture.