| Abstract [eng] |
This paper analyses the efficiency of heat production in a boiler house using biofuel (shredded wood). It is noted that chopped wood usually contains a certain amount of water, since the fuel is usually transported directly from the logging sites. The collected data show the limits within which the amount of water in biofuel varies in different seasons. During combustion, the water contained in biofuel needs to be evaporated, and for this energy is consumed, which is emitted with the smoke. To capture this energy, it is necessary to cool the smoke below the smoke dew point temperature. After cooling the smoke below the dew point, the water in the smoke condenses and thus the evaporation / condensation energy is recovered. The lower the temperature of the smoke, the more energy is removed from the smoke, and the boiler house efficiency is higher. Additional equipment such as a condensing economizer or an absorption heat pump is required to reduce the flue gas temperature. The study presents calculations and results obtained in a real boiler house, how much additional energy can be recovered in the smoke condensation economizer, cooling the smoke with the return water of the heat networks and how much additional energy can be recovered when cooling the smoke by the heat removed in the circuit of the absorption heat pump evaporator. The efficiency of the biofuel boiler house depends on the temperature of the flue gas. The lower the smoke temperature, the more energy is extracted from the same amount of fuel, or in other words, less fuel is used to produce the same amount of energy. |
