330MW高背压供热机组热力特性研究

Thermodynamic Characteristics of a 330MW Unit with High Back-pressure Circulating Water Heating

精确掌握热电联产机组电功率-热负荷-标准煤消耗量的关系特性,可以对机组进行精细化管理,实现运行成本最小化及盈利最大化。基于EBSILON软件建立的评估模型,对采用吸收排汽余热的某330MW亚临界高背压供热机组,计算分析了热网循环水流量、回水温度、汽轮机进汽流量等参数对供热特性的影响规律,研究了高背压供热模式的电功率-热负荷-标准煤消耗量的关系特性。结果表明:高背压供热机组以热定电模式运行,调峰能力较差;不同电负荷下机组总标煤消耗量随供热负荷率增加呈线性增加趋势;与连通管抽汽供热模式最大供热工况相比,给定汽轮机进汽流量,高背压供热模式具有较高的电负荷和热负荷能力;给定供热量下高背压供热模式具有较好的供热经济性:供热负荷率为60%、70%和80%时,标煤消耗量差值分别为11.78t/h、15.69t/h和19.61t/h。建议供热机组以能耗最低或盈利值最高为目标,进行供热机组厂级优化分析,实现智能优化控制。

Accurately acquiring the relationship of power unit,heat load and standard coal consumption of cogeneration unit, is the key of unit delicacy management and implementing minimize operating costs as well as maximize profits. A theoretical model of cascade heating system with high back-pressure for 330MW unit was established on the base of EBSILON commercial software. The influence law of heat net circulating water quantity, inlet circulating water temperature and main-steam flow on thermodynamic performance was studied. The relationship of power unit, heat load and standard coal consumption was analyzed. The results show that the unit power tends a significant strong relation with heat load for cogeneration units with high back-pressure circulating water heating, which owns poor power-regulating capacity. The standard coal consumption tends to increase linearly with heat load rate. Compared with maximum heating condition of heat mode using communicating pipe extraction, high back-pressure heating mode shows better power unit and heat load under fixed main-steam flow, and better thermal economy under fixed heat load:the standard coal consumption of high back-pressure heating mode is 11.78,15.69 and 19.61t/h respectively than that of heat mode using communicating pipe extraction for heating load rate 60%,70% and 80%. It is recommended that operation optimization of the whole coal-fired cogeneration plant should be implemented urgently, using the guidance of the lowest energy consumption or the highest profit value.