摘要
针对供热空冷机组(尤其是进行过供热改造的凝汽式空冷机组)普遍存在供热抽汽压力过高的状况,提出了在供热期内将供热抽汽流引进背压汽轮机,先驱动给水泵再进行供热运行模式,并以山西某电厂实际机组为例,编写计算程序分别进行额定工况和变工况下排汽压力和供热抽汽量的校核计算。结果表明:以热网加热器作为驱动给水泵背压机的冷源,背压机功率输出稳定,能够满足给水泵的功率需求且不影响供热过程。与电动泵运行模式进行经济性对比,汽动泵运行具有良好的经济效果,在额定主蒸汽量下,机组净热耗降低约182 kJ/kWh,投资回收期计算显示,采用所述模型运行,约3年即可回收全部的改造费用和设备投资。
In the light of the situation that the heat supply and extraction pressures of heat supply air-cooled steam turbines are excessively high in most cases,especially those of the condensing type ones which had been modified for heat supply,proposed was a mode for the operation of steam-driven pumps during which the steam extracted from the aircooled steam turbines was first introduced into back pressure type steam turbines to do work and drive the feedwater pumps and then to provide heat. With a real unit in a power plant in Shanxi province serving as an example,a calculation program was prepared to conduct a check calculation of the exhaust steam pressure and the steam flow rate extracted for heat supply under the rated load operating condition and the off-design operating conditions respectively. It has been found that with the heaters in the heating network serving as the heat sink for the back pressure type steam turbines to drive the feedwater pumps,the output power of the back pressure type steam turbines can be stabilized,capable of meeting the power demanded by the feedwater pumps and not influencing the heat supply process.Compared with the cost-effectiveness of the operating mode in which motorized pumps are adopted,that of the mode in which steam-driven pumps are employed is better. At the rated main steam flow rate,the net heat rate of the unit will drop by about 182 kJ / kW. h. The calculation result of the investment repayment period shows that if the abovementioned operating mode is adopted,all the modification cost and investment in the equipment items can be paid back in around three years.
出处
《热能动力工程》
CAS
CSCD
北大核心
2014年第1期46-52,107,共7页
Journal of Engineering for Thermal Energy and Power
基金
国家重点基础研究发展计划(973计划)基金资助项目(2009CB219801)
关键词
空冷机组
供热
汽动给水泵
变工况
可行性研究
air-cooled unit,heat supply,steam-driven feedwater pump,off-design operating condition,energy saving
