Abstract:

This paper introduces the working principle and thermodynamic performance of “zero output technology of low-pressure cylinder”, the influence of variation of operating back pressure on safety and economy of zero output technology of low-pressure cylinde is analyzed in detail. The results show that: when the unit is running under the condition of zero output of low-pressure cylinder, under the main steam flow of 1961t/h condition, the operating back pressure decreased from 0.0049MPa to 0.0029MPa, the volumetric flow of low-pressure cylinder increased from 3387137m³/h to 5449587m³/h, the heating load increased from 862.4MW to 899.0MW, and the coal consumption of unit decreased from 198.7g/(kW·h) to 186.0g/(kW·h); Under the main steam flow of 1861.3t/h condition, the operating back pressure decreased from 0.0049MPa to 0.0029MPa, the volumetric flow of low-pressure cylinder increased from 3391026m³/h to 5446086m³/h, the heating load increased from 821.9MW to 858.6MW, and the coal consumption of unit decreased from 201.7g/(kW·h) to 187.0g/(kW·h). This shows that when the unit is running under the condition of zero output of low-pressure cylinder, through increasing the volumetric flow of low-pressure cylinder, the safety of operation of the low-pressure cylinder will be enhanced, so it is beneficial to improve the safety of operation of the unit, and it can also decrease coal consumption and increase economic benefit through properly reducing the operating back pressure of the unit.

Key words: low pressure cylinder zero output, thermodynamic performance, operating back pressure, safety, economy, coal consumption

摘要：

介绍了“低压缸零出力技术”的工作原理及热力系统，并针对运行背压变化对低压缸零出力技术安全性及经济性的影响进行了详细分析。结果表明：机组在低压缸零出力工况下运行时，在主蒸汽流量为1961.0t/h情况下，运行背压由0.0049MPa降到0.0029MPa，低压缸容积流量则由3387137m³/h增长到5449587m³/h，供热负荷由862.4MW增长到899.0MW，机组发电煤耗由198.7g/(kW·h)降低到186.0g/(kW·h)；在主蒸汽流量为1861.3t/h情况下，运行背压由0.0049MPa降到0.0029MPa，低压缸容积流量则由3391026m³/h增长到5446086m³/h，供热负荷由821.9MW增长到858.6MW，机组发电煤耗由201.7g/(kW·h)降低到187.0g/(kW·h)。可见机组在低压缸零出力工况下运行时，通过增加低压缸的容积流量，会增强低压缸运行的安全性，因此通过适当降低机组运行背压，有利于改善机组运行的安全性，并且能够降低机组的发电煤耗，提高机组的经济效益。

关键词: 低压缸零出力, 热力系统, 运行背压, 安全性, 经济性, 发电煤耗