Investigation the effect of outlet air flow and chamber temperature on some bio-char properties of wheat straw in a fixed-bed oxidative pyrolysis

Abstract

Soil plays an important role in the sustainability of ecosystems. In recent years, the increasing growth in the degradation of soil resources has drawn attention to management strategies for maintaining the soil quality. Researchers have recently studied the impact of using biochar on physical and chemical properties of soil. It has been found that adding biochar improves the soil quality. Some factors such as pyrolysis chamber conditions, pyrolysis peak temperature and air flow rate affect the physical and chemical properties of biochar including the density, pH, ash content, and so on. In this study, the effect of changes in the air flow rate and chamber temperature in the fixed-bed oxidative pyrolysis on the biochar yield, ash content, density and pH were investigated. For this purpose, a fixed-bed biochar production apparatus with varying chamber temperature and flow rate of outlet air was designed and manufactured. The experiments were performed at four air flow rates of 20, 25, 30 and 35 L min^-1 and four temperatures of 350, 400, 450 and 500 °C for wheat straw. The results showed that increasing the temperature and flow rate of the outlet air from the chamber increased the ash content and pH. However, increasing these parameters decreased the biochar bulk density and yield.