Biomass Ten (10 tonnes-per-hour) of wood is burned directly in a boiler to generate saturated steam at 200°C. Boiler feed water enters the boiler at 20°C. The higher heating value (HHV) of the wood is 18 GJ/tonne and the delivered cost is 40 E/tonne. The generated steam is run through a turbine-generator unit to generate electricity. The steam pressure at the steam turbine exit is 100 kPa, which is piped to a low-grade heating system. The boiler efficiency is 75%, the steam turbine isentropic efficiency is 85%, and the generator efficiency is 95%.
Draw a process flow diagram of the power plant and illustrate the cycle on a temperature-entropy (T-s) diagram, identifying all the state points on both sketches.
Calculate the steam cycle heat rate, the amount of steam generated, the electrical power output, the overall electrical efficiency of the power plant, and the heat-to-power ratio. Determine the net hourly revenue if the REFIT (renewable energy feed-in tariff) is 0.11 E/kWh.