Study On Fuel Utilization Of Waste Auricularia Auricula Bran Biomass

Auricularia auricula bran is the residual solid medium produced by planting Auricularia auricula.It is mainly composed of lignocellulosic materials,and the moisture content is as high as 70%.China produces a large amount of surplus Auricularia auricula bran every year.Due to the lack of large-scale treatment methods,it is randomly discarded in the field,resulting in serious environmental pollution and waste of resources.It is urgent to develop practical and feasible resource utilization methods.Energy utilization is a way to absorb Auricularia auricula bran in large quantities,which can fundamentally solve the ecological and environmental pressure of Auricularia auricula bran.This method not only makes use of a large amount of biomass energy contained in the bran,but also can become a livelihood project to increase the income of bacterial farmers.Increasing calorific value is the key to the utilization of biomass energy,and the most effective way to improve the calorific value of Auricularia auricula bran is to reduce its moisture content.In this paper,Auricularia auricula bran was dehydrated by thermo-compression drying method.Through theoretical and experimental research,the effect of thermo-compression drying process of waste Auricularia auricula bran on the moisture content of Auricularia auricula bran was analyzed;The response surface optimization method was used to obtain the optimal parameters in the thermo-compression drying process of bacterial bran;The effect of heating rate on combustion process was studied by thermogravimetric analysis;The ash formation and slagging of bacterial bran combustion after compression were studied by combustion method.The specific conclusions are as follows:Auricularia auricula bran is a typical biomass with high water,low heat and low pollution.Its developed pore structure and high specific surface area have a high surface tension on the liquid,making it difficult to remove water.Bacterial bran contains hydroxyl,ether,alcohol,ester,phenol and aromatic hydrocarbons,which makes it show hydrophilic properties in macro view.The thermogravimetric process of waste Auricularia auricula bran can be roughly divided into three stages: water analysis,volatile and fixed carbon combustion and burnout.The thermo-compression drying of Auricularia auricula bran mainly goes through three processes: steam modification,press dehydration and thermal dehydration.The saturated steam is introduced into the bacterial bran,which rapidly increases the temperature and humidity of the bacterial bran and softens the medium skeleton of the bacterial bran.At this time,when a certain external force is applied,the bacterial bran is more likely to deform under the same pressure,and the liquid in the pores will seepage,so that the water can be removed in the form of liquid.The medium skeleton of bacterial bran deforms under pressure,and the liquid in the pores generates seepage.Before the pressure load is saturated,the deformation degree of the medium skeleton gradually accumulates with time,and finally tends to be stable.Under the action of heat,the water viscosity in the bacterial bran decreases and the permeability of water increases,creating strong conditions for the removal of water.During the dehydration process,the hot pressing plate provides a temperature higher than that of the water gasification in the bacterial bran.The gas generated by the endothermic gasification of the water near the hot pressing plate in the bacterial bran will affect the internal pore structure of the bacterial bran and produce a "discharge effect" with the discharge of the gas,so that the water in the particles will migrate to the particle surface and be removed.Taking the moisture content of 35% as the target,through the response surface optimization method,it is known that among the influence levels of various factors,saturated steam has the greatest influence on the thermo-compression drying effect.The optimal process parameters are: feeding saturated steam for 10.087 s + pressure of 4.053 mpa +temperature of 121.314 ℃ + holding pressure for 15.22 min.The thermo-compression drying experiment was carried out under this condition.The average moisture content of bacterial bran was 34.8% and the calorific value was 9780 k J/kg in three parallel experiments.It can be seen that the obtained parameters are feasible.When the heating rate is low,the bacterial bran is easy to be ignited and has good performance in the early stage of combustion.The increase of heating rate is helpful to the burnout of bacterial bran.After thermo-compression drying,the ash content and ash melting slagging amount of bacterial bran decreased,and the slagging trend of bacterial bran weakened.When burning at 800℃,the main component of ash is Ca CO3.With the increase of combustion temperature,Ca CO3 decomposes into Cao and exists stably in ash.