Research On The Hot-air Drying Characteristics Of Biomass Fuel

With the swift development of global economy and the advanced course of industrialization,the contradictions between large energy demands and shortage of fossil energy become more and more acute.The biomass energy will be the motivity of sustainable development for national economy due to the characteristics,such as rich reserves,renewable and realizable of zero release of CO2:The biomass power generation has become an important industry in the biomass energy field.The influence of water content is so serious that drying biomass becomes extremely essential.The design of biomass power plants often refers to the coal-fired power plants,which results in relatively high temperature flue gas that can be recycled.Using the high exhaust gas to dry the biomass fuel will not only improve energy efficiency,but also realize the cyclic utilization of the high temperature gas.Therefore,this application has great industrial significance.Firstly,this paper simulates the air flow and temperature in the heating systems by Fluent software,which analyses the results of the simulation results in order to put forward suggestions for improvement.The physic and chemical characteristics of different type biomass fuel is researched from the technical and element analysis.Through identifying the drying temperature range by the thermogravimetric experiment,these experiments provide a certain theoretical basis for the drying dynamics of biomass fuel.The results show that the drying temperature should be lower than 150??Secondly,it's analyzed that the influence of drying temperature,initial moisture content,relative humidity and wind speed on the drying time by multiple factors orthogonal method.The results show that the drying time is influenced by the four factors including the temperature,which has the greatest influence.The influence between wind speed and initial moisture content is close and the relative humidity is the least.Overall,on the same drying conditions,the drying rate is shelled plants,straw and wood.We take T=120?,RH=25%,v=1.2m/s as the ideal drying condition.Finally,this paper finishes the analysis of moisture content balance in the boiler combustion system in biomass power plants and the influence of different initial moisture content in biomass fuels to the moisture content.According to the operating parameters of 48t/h biomass power plants,this paper finishes the effect of flue gas waste heat.The two boilers can save the standard coal consumption at about 1687.27 tons and save money at about 1.18 million yuan and dry the biomass at about 67.35 thousand tons each year.Taking wheat straw as an example,the Page model is the optimal model to forecast biomass fuels during the drying process and optimizes the industrialized drying process of biomass fuels.