Energy Consumption in Processing of Black Tea in Tea Factories

This study was carried out to determine energy consumption in various stages of processing of black tea in tea factories at Guilan province in Iran. Direct energy (thermal energy and electric energy) and indirect energy (man power, depreciation, and lubricants) were measured and evaluated in 9 tea factories; four factories using diesel fuel and the remaining five used natural gas. The results showed that approximately 70 percent of the energy consumed in tea processing is thermal energy of which 31 percent used in withering and remaining 69 percent used in drying stage. The amount of thermal energy consumed in tea factories with natural gas fuel is about 5 percent less than that in factories used diesel fuel. Electric energy has contributed 28 percent of total energy consumed in production of black tea. Withering, rolling and air heaters used 58.16, 16.58 and 11.39 percent of energy consumption in tea factories, respectively. Man power has contributed the lowest percentage of energy consumption in tea processing. Inappropriate designing, burnout ovens, lack of proper insulation, and improper structures of mechanical parts are responsible for significant energy losses at tea factories. The following steps could help reducing energy consumption in tea processing: installation of new designed furnaces, insulation the present furnaces and drying machines, and improving power supplying systems.