Rice Husk Briquette:
In household level, rice husk is being used for parboiling of rice or for cooking. The rice husk that is produced in rice mills is a disposal problem for the rice mills because of its large volume. It is difficult to carry. Often the operators resort to burning the rice husk and also much of it ends up being dumped in pit or in river. Rice husk also gets airborne and is strewn about by wind thus causing air pollution too. It is not usually retailed in small amount, but large amount may be retailed to the poultry industries.
The situation has changed a little. Modern rice mills are combined with rice parboiling industries. In most cases most of the rice husk is used for rice parboiling. There remains only a small amount of rice husk left. The available rice husk is being used for producing briquette. Briquette is a modern biomass fuel. It is biomass in condensed form with increased volumetric calorific value. Moreover, the briquette is more user friendly and easy controllable. Different types of biomasses like sawdust, rice husk may be converted to briquette.
Research on briquette production has been carried on in Bangladesh successfully. Khulna University of Engineering and Technology has done much research in collaboration with Asian Institute of Technology (AIT), Thailand. The developed technology has been transferred to private sector. A few private companies have come forward to manufacture and market the briquetting tools. Briquette from rice husk and sawdust is becoming more and more popular all over Bangladesh. It is now available in markets on commercial basis. Fig.12 shows briquette produced from rice husk.
At the moment, there are more than 900 briquette machines operating in Bangladesh. These produce briquette from rice husk. Rice husk briquette is produced almost all over the country and briquette is becoming more and more popular among the users who need large amount of fuel, such as restaurants, hostels. However, some marketing initiatives and / or intervention of the authorities, most of the bulk fuel wood consumers could be opting to use briquettes.
Rice husk based briquette is being produced almost all over the country and briquette is becoming more and more popular among the users who need large amount of fuel, such as restaurants, hotels. However, with some marketing initiatives and/or the intervention of the government authorities, most of the bulk fuel wood consumers could be opting to use briquettes. Figure 13 shows a briquetting machine in operation.
Saw dust based briquette production has not become popular in Bangladesh. It is not known whether there is any sawdust briquette manufacturing plant in Bangladesh. One problem may be the industries related to wood are not concentrated, rather scattered. As such the available saw dust is relative small in amount. Some of the foreseeable activities for producing briquette from saw dust are: sawdust must be collected from various sources around the country; bottlenecks such as the manual sawdust sieving must be alleviated; adequate plant spares need to be stocked; proper operation and maintenance schedules need to be established; the plant complex need to be structured for more efficient operations; and to enhance shelf life of briquettes respectively. Given the dispersed sources of sawdust (sawmills) around the country and the transportation costs associated, it may also be feasible to set up smaller briquette plants in different regions.
While small portions of the sawdust are retailed to interested buyers, the sawmill operators generally have a disposal problem. Often the sawmill operators resort to burning the sawdust and also much of it ends up being dumped. Sawdust also gets airborne and is strewn about by wind thus causing air pollution too. Utilizing the available sawdust for making briquettes will solve the disposal and the environmental pollution problems of sawdust. It will reduce the firewood consumption and reduce pressure on the forests to the extent of its usage.
There are about 25,000 wood based enterprises including small/medium furniture manufacturers, sawmills, and manufacturers of particle boards, plywood, etc. These industries generate a substantial amount of sawdust and other wood wastes that can be used for manufacturing briquettes.