Study On The Characteristics Of Continuous Baking And Molding Of Several Typical Agricultural And Forestry Biomass

Biomass is the fourth largest energy followed oil,coal and natural gas.Biomass is cheap,easy to get,environmentally friendly and renewable.C hina is a country with energy shortage,however it is country has a large amount of biomass resources.The importance of biomass energy is well known,but biomass has low energy density,and hydrophilic ability,which result in poor transportation and storage properties.At the same time,it’s heat value is low,it is only about 1/2 of the coal,1/3 of the oil.This paper focuses on biomass baking and molding application research to improve the heat value of biomass and other properties,so the pre-treated biomass can be easy to transport and store.The main research contents and results as followed:This paper selected representative agricultural and forestry waste as the research objects,it includes biomass rice husk,corn stalks and eucalyptus chips.Element analysis and industrial analysis were used in the three kinds of biomass raw materials to compare the different between the materials.The thermogravimetric analysis of three kinds of biomass materials was carried out at different heating rates(5 ℃/min,7.5 ℃/min,10 ℃/min)and the results found that the 45℃ ~ 95℃ was favorable for biomass drying,while 200 ℃ ~ 300 ℃ was proper for biomass baking.With the temperature range of 150 ℃ ~ 350 ℃ and baking time 30 min,a fixed bed pyrolysis device was used to carry the baking experiment.When the baking temperature is 225 ℃ ~ 250 ℃,the mass of raw material is reduced by 1/3,while the energy keep more than 80%.The solid phase product baking at the temperature ≤ 265 ℃can be molding well without adding any adhesive.At the temperature of 200 ℃,220 ℃,240 ℃ and 260 ℃,continuous baking experimental were carried on the device,the results showed that comparing with the fixed bed roasting,continuous baking has a better baking effect which produced uniform color and luster product in one batch baking experiment,due to the material in the process of could be turning up and down,and having a balance heating.As the increasing of baking temperature,the heat value of product and quality gradually increase,mass and energy retention rate gradually reduced.At the baking temperature of 240 ℃,bake time 35 min,the mass of the baking material product is about 65%,energy retention rate over 86%,which fit the requirement of baking.Molding experimental results show that at baking temperature of 220 ℃ ~ 240 ℃ and the pressure of 6k N or 7 k N,the molding columnar particles have a certain ability to resist damage.At the same pressure,different baking products have a different level of lower in grain density.With the increasing of the baking temperature,the density is lower.The same materials show the same compression ratio(the ratio of the pellet formation density and bulk density)after baking,while different materials show a different compression ratio.Corn stalks has the largest compression ratio,about eight times,and the second is the eucalyptus wood chips,about 5 times,the minimum is rice husk,about 3 times.After baking,the biomass is convenient transportation,has lower ignition and high heat value,could be combust quickly.Therefore baking is one of the methods on conversion o f biomass,it provide a effective method on pre-treat of biomass.