A daily optimal operational schedule for cogeneration systems in a paper mill

This paper describes the strategy of a daily optimal operational schedule for cogeneration systems operating in a paper mill. The cogeneration systems consist of three generators, the several auxiliary devices which include three auxiliary boilers, two waste boilers and three sludge incinerators. One unit generates the electrical and the thermal energy using a back pressure turbine. The other two units generate both of these types of energy using an extraction condensing turbine. Auxiliary devices operate to supplement insufficient thermal energy to the thermal load with three units. The cogeneration systems have a large capacity which is able to supply enough thermal energy to the thermal load, however the electric power generated is insufficient to satisfy the electrical load. Therefore the insufficient electrical energy is supplemented by electrical energy buying from the utility. Simulation for operational schedule was carried out using Evolutionary Programming (EP). The operational cost shows that efficiency is improved by 10% compared with the past. The result reveals that the proposed modeling and the scheduling strategy can be effectively applied to cogeneration systems of another paper mills.