为解决供热机组日益严重的热电耦合问题，提出了抽汽凝汽供热、低压缸空载供热以及高低旁路联合供热等热电解耦模式。目前针对不同热电解耦模式电热特性及供热能力的对比研究较少，因此以某300 MW亚临界供热机组为例，利用Aspen Plus V11软件对抽汽凝汽供热（背压14 kPa）、低压缸空载供热（背压3 kPa）、高低旁路联合供热等模式进行建模。采用汽轮机变工况计算方法，从机组电热特性、热力学性能等方面进行对比分析。结果表明：在相同主蒸汽量条件下，低压缸空载供热模式最大供热抽汽量相较抽汽凝汽供热模式提升约185 t/h。高参数膨胀机进汽量和汽轮机进汽量的比值（简称进汽比）对高低旁路联合供热模式的最大热电比影响较大。当主蒸汽流量保持不变时，高低旁路联合供热模式的最大热电比随进汽比升高而增大，相较于抽汽凝汽供热、低压缸空载供热等模式，其最大热电比分别提高了1.981倍和1.227倍。主蒸汽量为额定值时，3种供热模式采用等效电法计算所得的机组发电标准煤耗分别为311.64、262.32、258.22 g/kWh。

In order to solve the increasingly serious thermo-electric coupling problem of heating units, thermo-electrolytic coupling modes such as extraction steam condensing steam heating, low-pressure cylinder no-load heating, and high-low bypass combined heating were proposed. At present, there are few comparative studies on the electric heating characteristics and heating capacity of different thermoelectric coupling modes. Taking a 300 MW subcritical heating unit as an example, the extraction steam condensing steam heating(back pressure 14 kPa), low-pressure cylinder no-load heating(back pressure 3 kPa) and the high-low bypass system combining with heating mode were modeled by using Aspen Plus V11 software. The electric heating characteristics, thermodynamic properties of the unit were compared and analyzed by using the method of variable working condition calculation. The results show that under the condition of the same main steam flow, the maximum heating and steam extraction capacity of low-pressure cylinder no-load heating mode is about 185 t/h higher than that in extraction steam condensing steam heating mode. The ratio of steam intake from the high-parameter expander to the steam turbine intake (abbreviated as steam intake ratio) has a greater impact on the maximum heat-to-electricity ratio of the high-low bypass heating mode. When the main steam flow remains constant, the maximum heat-to-electricity ratio of the high-low bypass heating mode increases with the increase of the inlet steam ratio. Compared with the extraction steam condensing heating mode and the low-pressure cylinder no-load heating mode, the maximum heat-to-electricity ratio increased by 1.981 and 1.227 times respectively. When the main steam flow is the rated value, the standard coal consumption of generating unit calculated by the equivalent electricity method for the three heating modes is 311.64, 262.32 and 258.22 g/kWh respectively.

0 引言

1 供热机组概况

   1.1 机组汽轮机概况

   1.2 工业抽汽需求

2 机组热力系统计算模型

   2.1 物性方法选择

   2.2 机组热力系统模型的建立

   2.3 模型准确性验证

   2.4 热力学性能分析方法

   2.5 发电标准煤耗分析方法

3 热电解耦模式

   3.1 低压缸空载供热（背压3 kPa）模式

   3.2 高低旁路联合供热模式

4 结果与讨论

   4.1 电热特性分析

   4.2 热力学性能分析

   4.3 发电标准煤耗分析

5 结论