Designing and Evaluating Biochar Pyrolysis Kiln

Abstract

Enhanced biochars pyrolysis Kiln was developed and used to produce biochars from rice straw and date palm fronds biomass. The pyrolysis kiln was an internal rectangular chamber with a total volume of 0.30 m3. the pyrolysis temperature either to reach 250 °C, 450 °C or 650 °C with heating rate of 5 °C min−1. Three residence times (2, 4, 5 h) were examined to study the impact of temperature on the quality of biochars. Study measurements included the chemical properties, elemental analysis, scanning electron microscopy (SEM) images and elemental compositions on the surfaces of produced biochars. Rice straw and date palm fronds biochars yield decreased with increasing pyrolysis temperature from 250 °c to 650 °c. Also volatile matter yield decreased with increasing pyrolysis temperatures. Ash content and fixed C in rice straw biochars increased with increasing pyrolysis temperatures. Where, minimum recorded ash content was 23.5 % at 250 °c temperature for 2 h residence time, and maximum recorded value was 32.5 % at temperature degree of 650 °c for 5 h residence time, with similar data trend for date palm fronds biochars but with lower ash content values. Both H and O decreased in rice straw biochars with increasing pyrolysis temperature, while C content increased. N content had no constant change behaviour as it increased until temperature of 450 °c, but decreased afterwards at 650 °c. In date palm fronds biochars pH increased with the applied pyrolysis temperatures and there was decrease in CEC with increasing temperature.