Research On The Carbonization Pyrolysis Characteristic Of Chestnut Shell And Sawdust

The biomass resources are the fourth energy sources in the world, which is just falling behindpetroleum, coal and the natural gas, Biomass resources are rather abundant in China. Annually, theresidual stalk, grain husk and other agriculture biomass are equal to about 200 to 250 million tonsof coal, and the forest biomass residues are equal to about 20 million tons of coal. In addition, theorganic waste of town, which is equal to 200 million tons of coal, can be exploitured. Biomass canbe used in a variety of ways to provide energy. Pyrolysis technology, which can directly changebiomass to charcoal, liquid and gas, has been concerned greatly.In China, the chestnut is planted widely, and the yield is the most of the world, which accountfor three quarters of the world. When collecting and processing, there are a lot of chestnut shell,which is always deserted. The chestnut shell pyrolysis is studied systematically and compared withthe sawdust pyrolysis. The main contents and conclusions are as following:The pyrolysis process and kinetics of the chestnut shell is studied applying thermogravimetricanalyzer. The pyrolysis experiments are performed up to 1073 K at heating rates of 5, 10, 20, and40 K/min. The chestnut shell pyrolysis contains of five pyrolysis events, and activation energies ofthe tow main pyrolysis events are 176MJ/mol and 255MJ/mol respectively. The chestnut shellpyrolysis mechanism accords with the planar pervasion, n=1/2 of Jander equation.The distribution of charcoal, liquid and gas of biomass pyrolysis at a temperature range from300℃to 750℃is studied in the small tubular reactor. The yields trends of products distribution ofthe two species are the same. As the pyrolysis temperature increases the yield of char decreaseswhile gas products increases, and the liquid yield increases firstly and then decreases. The yields ofchar and gas of chestnut shell pyrolysis is higher than those of sawdust pyrolysis, while the yield ofliquid of chestnut shell pyrolysis is lower than that of sawdust pyrolysis. The major gas products ofchestnut shell are CH₄, H₂, CO and CO₂. Between the temperature 541℃and 622℃, the content ofCH₄ and H₂ reaches up to 24% and 27.5% respectively, and gas heating value is 14.4MJ/m3.The influence of heating rate and reaction temperature on the pyrolysis of chestnut shell in thebatch reactor has been investigated. The heating rate has little influence on the yields of char, liquidand gas products. The influence of reaction temperature on the yields of char, liquid and gasproducts are similar with the small tubular pyrolysis reactor. But compared with the small tubularpyrolysis reactor, the char and liquid yields reduce and the gas yield increases.