| 摘要 |
A power plant includes a steam boiler that delivers a rated amount of high-pressure steam at rated temperature and pressure to a steam turbine having a high-pressure stage and at least one low-pressure stage driven by low-grade steam exhausted from the high-pressure stage. A main generator, driven by the steam turbine, furnishes electricity to a variable load. When the load decreases below rated value, the boiler operation is maintained, but low-grade steam exhausted from the high-pressure stage of the turbine is diverted from the low-pressure stage to a heat store large enough to accumulate heat during the time that the power plant operates at less than rated load. A waste heat converter, having its own generator, is responsive to the low-grade heat stored in the heat store, and can be operated selectively to furnish electricity to the load to supplement the output of the power plant. The output of the waste heat converter can be used for peak-power purposes, thereby reducing the size of the main power plant, as well as for furnishing low-level power during shutdown of the main power plant. Moreover, when in operation, the boiler and the high-pressure stage of the turbine operate at peak efficiency, which results in reducing the fuel cost of the power plant. |
