Thermo-chemical behaviour of maize cob and bean straw briquettes

Abstract

• Pyrolysis of maize cob and bean straw briquettes were studied. • Briquetting conditions had no impact on thermos-chemical behaviour. • Temperature had the dominant effect on yields and properties of pyrolysis products. • Pyrolysis of briquettes was suited to maximise the production of char. • Up to 45% energy content was stored in smokeless char like material. Pre-treatment is essential to reduce logistic costs of agricultural residues. This work examined the interactions between pre-treatment conditions and thermo-chemical behaviour on product yields and properties. The effect of pyrolysis operating and briquetting conditions (i.e., temperature, pressure and bean straw-maize cob blend) on yields and properties of pyrolysis products from maize cob, bean straw and blended briquettes were investigated. It was found that briquetting conditions, heating rate and carrier gas flow rate had negligible effects on yields and properties of pyrolysis products. Temperature was the dominant factor that effected the yield and properties of the pyrolysis products. Increasing pyrolysis temperature increased the gas and reduced the char yield. Up to ∼45% of the energy content of the raw material can be stored in smokeless char like material that can be easily transported and used for energy production e.g., household cooking. Pyrolysis of agricultural residues has the potential to reduce harmful particulate emissions whereas the high-water content bio-oil can be used as a binder in briquette production to reduce the pressure and temperature applied.