INVESTIGATION ON RENEWABLE ENERGY INTEGRATED DRYING SYSTEM FOR PRODUCTION OF SUPERIOR QUALITY SHEET RUBBER

Abstract

The conventional practice of drying sheet rubber is by biomass combustion with firewood as fuel in a smoke house. The heat balance of existing conventional smoke houses was studied and it revealed that, out of 3550 MJ thermal energy supplied as heat input, only 24.2 per cent of energy is utilized for drying the rest being lost through exhaust, walls and doors, moisture in fuel and other unaccountable losses . In order to enhance the drying efficiency, obtain a high quality of NR, reduce pollution, achieve energy substitution through renewable fuel, an attempt was made to develop a  renewable energy integrated drying system. This paper describes field investigation results of an integrated drying system installed at a group processing centre at the Elavampadam Rubber Producers’ Society (EMRPS), Kerala, India. The hot air temperature is maintained at 60°C, the optimum temperature for drying sheets by this system. Hot air from solar air heaters, producer gas and biogas were integrated in the drying chamber for supply during sunshine and  off-sunshine hours. The results revealed that, drying time was reached within 72 hours by using this integrated drying system compared to 144 hours with conventional smoke drying. Similarly, reduction of the desired moisture content from 25 per cent (d.b) to 5.3 per cent (d.b) was obtained during the process. Average thermal efficiency of integrated drying system was found to be 50.8 per cent. A superior quality of sheet rubber was obtained using the renewable energy integrated drying system comparing to RSS 1 to RSS 4 using conventional drying practice. The integrated drying system completely eliminates smoke during the drying process ultimately eliminating health hazards in the rubber processing industry and achieving attractive price for the product.

Keywords:   renewable fuel, integrated drying system, solar air heaters, biomass gasifier,   biogas, drying time, quality