Operation flexibility and energy efficiency co-optimization on a combined heat and power plant cogenerating power and multiple heat loads

Combined heat and power is an effective way to efficiently utilize fossil fuel and meet the diversified energy needs of industrial and municipal users. However, the operational flexibility of CHP units is restricted by the heat dominated operation mode. The double-extraction CHP unit can provide two types of heat loads, and its characteristics and constraints are more complex. Operation scheduling of multiple CHP units can effectively improve operational flexibility and reduce energy consumption of the CHP plant, and the collaborative optimization with flexibility and coal consumption as optimization objectives can obtain a comprehensive operation optimization. In this study, the 300 MW CHP unit were analyzed, and rated power load is reduced to about 157 MW due to supplying heat loads, and the energy efficiency and exergy efficiency can reach up to 90.57 % and 55.59 %. Then, an improved particle swarm optimization algorithm with Levy flight and hybridization calculation was derived and used to optimize the operation of three CHP units. According to the heat load of a typical day, the flexibility optimization can predict the power regulating range of the CHP plant, and the coal consumption be reduced by 0.19–23.74 t/d considering coal consumption optimization to achieve co-optimization can further.