Pyrolysis of Bioenergy Crops (Switchgrass and Miscanthus) Grown on Reclaimed Mining Land in West Virginia

Abstract. Pyrolysis has been identified as one of the thermochemical routes to convert biomass into biochar and bio-oil, usable low-grade fuel. However, biomass characteristics, which dictate pyrolysis product quality, vary with biomass species. The objective of this paper was to characterize the pyrolysis products of two energy crops (Miscanthus and Switchgrass) harvested from a reclaimed mine land in Appalachian region. The biomass samples were pyrolyzed using a fixed bed batch reactor under an inert condition and at a temperature of 500 ⁰C. Ultimate and proximate analyses of the pyrolysis products (i.e bio-oil, biochar and gaseous products) were carried out. The carbon content of the biomass, bio-char and bio-oil were found to be 46.8 – 48.02%, 77.72 – 80.23% and 54.68 – 59.68% respectively. Heating values were found to be between 19.-20 MJ/kg, 28.59 - 29.46 MJ/kg and 23.42 – 26.62 MJ/kg for the biomass, bio-char and bio-oil respectively. The carbon yield for both the bio-oil and biochar were slightly similar while the energy conversion efficiency for the bio-oil were higher than that of the biochars. The percent yield of the bio-oil were between 40.89 – 50.61%, 29.55 - 30.61% for biochars while the gas given off were between 19.48 – 28.50%. Carbon dioxide (CO₂), oxygen (O₂), nitrogen (N₂) and carbon monoxide (CO) were the predominant components of the gas given off during pyrolysis of the biomass samples. The result of this work gives a background information on the potential use of bioenergy crops cultivated on reclaimed mine lands in West Virginia.