Physical properties of briquettes from waste paper and wheat straw mixtures

Briquetting may be considered as a good idea to utilise low grade combustible materials obtained from biomass sources. Studies demonstrated that waste paper and wheat straw or their mixtures can be compressed to a relative density greater than unity and stabilised at that density without binder material. A reduction in the volume of the material also provides its technological benefit, i.e., the material could be transported and stored more economically than is possible at present. The effects of the briquetting pressure on the density, moisture content and compressive strength of the briquettes were examined at six different pressures (300, 400, 500, 600, 700 and 800 MPa). The optimum moisture contents and briquetting pressures were found to be, respectively, 18% and 780 MPa for waste paper, 22% and 710 MPa for wheat straw and 18% and 750 MPa for a 20%(w) waste paper–straw mixture. The effect of the temperature on the briquette density of wheat straw was determined. The best wheat straw briquettes were obtained at 385 K.