In Salt Refineries, drying is one of the high energy consuming step. For drying of salt, hot air generated by coal or fossil fuel fired boiler with a heat exchanger is used. The air is heated from ambient to the temperature of around 160 Deg C. This hot air is forced in to a fluidized bed dryer where salt around 4 – 5% moisture is dried to a moisture of 0.2%
In India there are many salt refining factories and all of them use either furnace oil/ diesel or coal/firewood for processing refined salt in the fluidised bed dryer. By using solar pre heated air at 60°C to 95° C (depending upon the solar radiation) the fuel consumption could be reduced. Introduction of solar heating system having a life span of more than fifteen years with proper maintenance will give an added economical sustainability especially during the fuel escalation periods. This will also provide a cleaner environment to the industries and the surroundings.
A 113 m2 area solar air heating system was installed at Sahayamatha Salt Refinery. The hot air obtained is drawn by an electrical blower. The hot air is transmitted by insulated metal pipes to the fresh air inlet point of the heat exchanger to preheat the air.
Sahayamatha Salt Refinery, Tuticorin