Pre-treatment of rice husk with acid and base for its effect on pyrolysis products

Abstract

The Pre-treatment of water washing, acid washing and alkali treatment on the biomass pyrolysis was experimentally done in a stainless steel reactor. The present work is to optimize the change in the quantity and quality of the oil fraction obtained from the pyrolysis, upon the different types of pre-treatment for acid washing and alkali solutions of agricultural biomass (rice husk). Different types of pre-treatment processes were used in this work, these are water leaching, acid treatment with dilute HCl and H2SO4, and alkali treatments are base treatment with NaOH and KOH. The EDX analysis results were showed that the metal ions of rice husk removed by treatment with acids and bases. The influence was more remarkable using acid compared to alkali solutions. Pyrolysis was done at optimal temperature 500oC and 5M HCl has been given the highest liquid product distribution, because it has least percentage of ions compared to all leaching processes upon the pre-treatments. The change in char percentage, and calorific values were observed. Ash content of untreated and treated biomass decreased through pre-treatment. Chemical compositions in rice husk such as extractives, hemicellulose, cellulose and lignin were investigated after pre-treatment processes. Thermal stability and decomposition rate of rice husk against acid and alkali treatments were examined by using TGA. Volatiles and moisture content of rice husk was also found using proximate analysis. The functional groups have been presented in the Pyrolysis oil, these are obtained at optimum conditions were analyzed by Fourier Transform-Infrared spectroscopy (FTIR).