Research On Ash Deposition Laws And Slagging Prevention Methods In Biomass Power Plant Boilers

China is a large agricultural country with a wide variety of biomass resources,wide distribution and large output.The theoretical biomass resources are about 5 billion tons.Because biomass contains a large amount of alkali metals,the furnace and heat exchanger surfaces are prone to slagging during combustion and utilization.By analyzing the mineral change process and the slagging mechanism on the surface of the heat exchanger during the biomass combustion process,the problem of slagging can be solved,which is of great significance for realizing the efficient and clean utilization of biomass.The samples taken in this article are from Guoxin Rudong Biomass Power Plant,including biomass raw materials,screen superheater slag,high temperature superheater slag,medium temperature superheater slag,low temperature superheater slag,economizer slag,and air preheater slag,cyclone fly ash,bag filter fly ash and slag.Perform XRD,XRF analysis and Fact Sage simulation calculations on biomass ash,cyclone fly ash,bag filter fly ash and slag prepared at different temperatures to explore the conversion process of minerals in biomass;for six kinds of heat exchange XRD and XRF analysis of the slag sample on the surface of the heat exchanger are carried out to explore the slagging mechanism on the surface of the heat exchanger;combined with the previous slagging mechanism,through the simulated mineral adhesion experiment,the mineral adhesion law is obtained and the reduction of power plant boiler heat exchanger is proposed.The method of surface slagging.The study found that: during the combustion of biomass,feldspar and potassium feldspar are converted into mayemite and forsterite at high temperature.Elements such as chlorine and sulfur are precipitated at high temperature,and it is easy to generate chlorine with alkali metal elements such as potassium and sodium.Chemical salts and sulfates.The presence of alkali metal chlorides and sulfates is the main cause of slagging on the heat exchanger surface.The analysis of six heat exchangers revealed that the surface slagging of the screen superheater,high temperature superheater,medium temperature superheater,and low temperature superheater is caused by the alkali metal salt forming steam at high temperature.The material particles stick together to form a low-temperature eutectic(potassium alum and glauberite);since the temperature near the economizer and air preheater is lower than the dew point temperature of acid gases such as sulfuric acid and hydrochloric acid,the acid gas is in the economizer and air Condensation on the surface of the preheater wets the fly ash particles on the surface,and the accumulation of fly ash particles causes slagging on the surface of the heat exchanger.The results of adhesion experiments show that calcium sulfate can effectively reduce the melting point of the entire system,and the adhesion of quartz,albite and alkali metal salts is good.Using albite and quartz as raw materials,the use of mineral injection can effectively reduce heat transfer in the boiler.Slagging on the surface of the device.