Abstract
The consumption of direct energy in the semi modern and modern Sri Lankan rice mills were studied to determine the energy consumption pattern, in order to enhance the energy conservation opportunities. In this paper, energy audit surveys of six-rice mills are presented from major rice processing districts of Polonnaruwa and Anuradhapura, which are geographically located in the North Western Province of Sri Lanka. Electrical and thermal energy, daily electrical consumption, husk utilization and boiler evaporation data were recorded and annual production and energy data were also collected. These data were evaluated in terms of the electrical and thermal specific energy, daily electrical and thermal energy consumption patterns, thermal and electrical sharing percentage and boiler efficiency. On an average basis, specific energy required to produce one ton of rice in semi modern and modern rice mills are as follows: electrical energy requirement is 42.84 kWh/ton and 41.10 kWh/ton respectively; thermal energy requirement for both drying and parboiling is 917 MJ/ton and 1092 MJ/ton respectively. During this process, boiler efficiency was about 30 % while utilizing 95% of husk produced in the rice mills.