Research On The Capture Efficiency Of Coal/Biomass Co-combustion Ash In Electric Field

With the rapid development of energy consumption and the extensive use of fossil fuels,energy shortages and environmental pollution problems have become increasingly prominent.Biomass and coal co-combustion has become a development trend,and co-combustion of biomass and coal in thermal power plant applications is the general trend.Biomass changes its combustion characteristics through co-combustion,and it will also make the charge and electric field characteristics of the co-combustion ash in the electrostatic precipitator show the difference with the pulverized coal.Therefore,it is necessary to study the capture efficiency of co-combustion ash in the electrostatic precipitator for the co-combustion technology.In this paper,the co-combustion of corn straw and anthracite with 0,5%,10%,15%,20% and 100%?caloric basis?,then the capture efficiency of dust samples are measured by the electrostatic trap system.The ¹⁴ C value of the collected ash samples was measured by Accelerator Mass Spectrometer,and the contents of biomass and anthracite in the co-combustion ash were measured accurately by ¹⁴ C technique.The influence factors of the capture efficiency of coal ash and biomass ash in different electric fields were analyzed by microscopic morphology,composition analysis,specific resistance,density and particle size distribution.The results showed that the best efficiency of the co-combustion ash was 10%,15% and 20%,and the capture efficiency was above 80%,while that of pure anthracite was the lowest.The ash trapping mainly focused on ? and ? electric fields,and the total ash capture efficiency of the added biomass was more than 90%.The capture efficiency of anthracite in the 20% co-combustion ash is 86.51%,10.95% and 2.17% respectively in the electric fields ?,? and ?.The capture efficiencies of 0% co-combustion ash?pure anthracite?were 66.96%,21.98% and 4.77%,respectively.It is indicated that the addition of biomass is beneficial to the capture of co-combustion ash in the electric field and the increase of capture efficiency.Analysts believe that the incorporation of biomass could increase the specific resistance of 20% co-combustion ash and the surface adsorption capacity increased adsorption of more fine particles to form agglomeration to increase its quality easy to capture.In the electric field ?,the capture efficiency of anthracite in 20% co-combustion ash is obviously higher than that of pure anthracite,which makes the capture efficiency of anthracite particles increase obviously.The density of pure corn straw is low and the quality light and easy to form fine particles so difficult to be trapped,and its poor adhesion even deposited in the electrostatic precipitator dust collector pole is also very easy to cause secondary dust,and 20% co-combustion ash as a result of the addition of biomass ash.The total capture efficiency is slightly lower.The results showed that the addition of biomass could improve the capture efficiency of fly ash in the electric field.The use of ESP or electric-bag composite dust collector can effectively remove the co-combustion ash particles.