**2.6. Briquettes**

Briquetting can be used as one of the solution to handle the jatropha press cake. The seed cake still has energy content of around 25 MJ/kg [18]. Since the briquette produces a lot of smoke, it is better to use the product outdoors. It can be used indoors with proper ventilation [19]. The carbonized process should be maintained at average time 10 minutes per 5 kg in order to prevent cake from complete combustion. Complete combustion will produce ash instead of charcoal briquette. Cassava and corn starch were used as binders for bonding the carbonized cake. Pandey et al. [20] reported that using 10% binder (cassava and corn starch) for pressed cake produced good jatropha charcoal briquette. The briquette from jatropha seed cake has emission of CO and CO2 are lower than briquette from wood. However, briquette from jatropha seed cake has much higher emissions of NO and NO2 than wood pellet. It is because of the presence of residual oil and higher nitrogen content [20].
