Design and construction of a dryer for carbonized briquettes.
MetadataShow full item record
Carbonized briquettes are some of the most used alternative source of energy for heat intensive domestic activities such as cooking and heating thereby creating their demand all year long. However, after manufacture, this type of briquettes still contains both physically and chemically bound water which renders them challenging to store, transport or use. Different carbonized briquettes drying technologies have been developed over time including open air drying, solar dryers and hybrid dryers. Both open air drying and solar drying require energy from the sun to be able to dry carbonized briquettes while hybrid dyers require electricity to be able to dry the briquettes. Thus, a low cost standalone thermal dryer that provides an alternative technique for drying was designed, constructed and tested to provide an alternative for drying carbonized briquettes during the wet season of the year and solve the shortcomings of open air drying, solar drying and hybrid dryers. This dryer uses a charcoal stove powered by briquettes destroyed during their manufacturing process (to minimize wastage) to heat up the air in the drying chamber. The heating system comprised of heat delivery pipe and the heat delivery fingers relay the heat from the stove to the drying chamber directly heating the briquettes and evaporating the moisture from them. Due to the increased temperatures (up to 70oC) in the drying chamber, vapor finally escapes through the chimney to the environment. This dryer is able to dry 36 carbonized briquettes (to up to 7% moisture content) in 6 hours in a 0.5m3 volume drying chamber and has an efficiency of 80.5%. It is easy to operate, simple in design and mechanism, light in weight, requires less labor and incurs a low operational cost. The performance of this dryer can further be improved by reducing heat losses through double walling, use of aluminum foil on the inside of the drying chamber or use of a synthetic foam coating such as Styrofoam, installing of a fan on to the drying chamber to improve air circulation inside the drying chamber and use of an eco-stove to generate more heat so as to reduce on the drying time. It is further recommended to use safety gear such as thermal gloves as operating the dryer involves working with higher temperatures that can cause harm to the human skin.