Production and characterization of briquettes made from rice straw and sawdust under high pressure and high temperature conditions

Abstract

Briquettes offer good value in terms of energy density. Briquetting of sawdust with paddy straw is a ray of hope for paddy straw waste utilization, which has been a burning issue in India for a long time. A commercial briquetting machine was used to make briquettes of sawdust with paddy straw in two different forms—shredded and chopped, in different ratios, separately. The ratio of paddy straw in briquettes was increased until the produced briquettes had an acceptable firmness. The maximum ratio of shredded paddy straw for which briquetting was possible was 40:60 with sawdust, whereas for chopped paddy straw it was 60:40 with sawdust. The briquettes were then analysed for different properties to assess their quality and durability. The shatter index of shredded straw briquettes and chopped straw briquettes varied from 0.10–10.12% and 0.26–4.54%, respectively. The friability index of shredded straw briquettes was in the range of 93.54-99.85%, whereas for chopped straw briquettes it was in the range of 89.89-99.90%. The volatile matter of shredded straw briquettes ranged from 79.60-83.89%, whereas for chopped straw briquettes it ranged from 76.69-86.07 %. The ash content of shredded straw briquettes was in the range of 9.83-13.07%, whereas for chopped straw briquettes, it was in the range of 6.60-16.44%. The fixed carbon content of shredded straw briquettes varied from 0.09 to 0.87%, whereas for chopped straw briquettes it varied from 0.11 to 0.59%. The results suggested that the densification experiments were successful and the briquettes produced were of good quality