Density Equation of Bio-Coal Briquettes and Quantity of Maize Cob in Phitsanulok, Thailand

One of the most important crops in Phitsanulok, a province in Northern Thailand, is maize. Base on the calculation, the quantity of maize cob produced in this region was approximately 220 kton year-1. The net heating value of maize cob was found to be 14.2 MJ kg-1. Therefore, the total energy over 874 TJ year-1 can be obtained from this agricultural waste. In the experiments, maize cob was utilized as the major ingredient for producing biomass-coal briquettes. The maize cob was treated with sodium hydroxide solution before mixing with coal fine. The ratios of coal:maize were 1:2 and 1:3, respectively. The range of briquetting pressures was from 4-8 MPa. The result showed that the density was strongly affected by both parameters. Finally, the relationship between biomass ratio, briquetting pressures and briquette density was developed and validated by using regression technique.