Tea manufacturing industries in India use natural gas, tea drying oil, wood, and coal for process heat. India is the second largest producer of tea [(1,137.07, China 1,761.00) million kilogram] in 2012. About 0.6–1.2 kg of coal is required to produce one kilogram of dried tea with average moisture of 2.5–3 percentage (w.b.). Biomass gasification is an established renewable energy technology for heat and power applications. Biomass gasifier based tea drying using five biomasses namely shisham (Delbergia sissoo), gulmohar (Delonix regia), bamboo (Banbusea Tulda), dimaru (Ficus lepidosa wall), and neem (Melia Azedarach L) were considered as feedstock for an experimental 10 kW thermal downdraft gasifier cum tea dryer. It was observed that bamboo chips producer gas gave the best calorific value (4.85 MJ Nm–3). Shisham gave average calorific value of producer gas 4.83 MJ Nm–3. Therefore, biomass gasification may be recommended for partial conventional energy substitution in tea manufacturing industries in India.
Keywords: gasification, tea drying, renewable energy, calorific value, biomass, fuel, India