Thermal power plant combined heat system and thermal power plant

Abstract

The invention discloses a thermal power plant combined heat system and a thermal power plant. The thermal power plant comprises a primary reheat condensing steam unit and a backpressure unit; and the combined heat system comprises a heat system of the primary reheat condensing steam unit and a heat system of the backpressure unit, wherein the heat system of the primary reheat condensing steam unit and the heat system of the backpressure unit share a heat recovery system from a condenser to a deaerator; condensation water of the primary reheat condensing steam unit and the supplement demineralized water of the backpressure unit are divided into two paths through the shared heat recovery system; and one path enters the primary reheat condensing steam unit, and the other path enters the backpressure unit. According to the combined heat system, the requirements of industrial high capacity and high parameter heat supply can be simultaneously met, the thermal cycle efficiency is greatly improved, the fuel consumption is reduced, and the pollutant discharge is reduced; and meanwhile, the power plant investment can be greatly reduced.

Description

technical field [0001] The invention relates to power equipment, in particular to a thermal system in a thermal power plant. Background technique [0002] In the prior art, in power plants that use steam turbines for power generation and heat supply, the intermediate extraction steam of the steam turbine of the primary reheat condensing unit is usually used for external heat supply, or the exhaust steam of the steam turbine of the back pressure unit is used for external heat supply. [0003] For the primary reheat condensing unit that uses steam extraction in the middle of the steam turbine to supply heat to the outside, there are mainly the following two problems: first, the steam volume of the steam extraction in the middle of the steam turbine accounts for a small proportion of the total steam volume of the steam turbine, and the heat supply is small; second, The pressure of the steam supply is required to be stable, but the pressure of steam extraction in the middle of t...

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Problems solved by technology

[0003] For the primary reheat condensing unit that uses steam extraction in the middle of the steam turbine to supply heat to the outside, there are mainly the following two problems: first, the steam volume of the steam extraction in the middle of the steam turbine accounts for a small proportion of the total steam volume of the steam turbine, and the heat supply is small; second, The pressure of the steam supply is required to be stable, but the pressure of steam extraction in the middle of the turbine decreases with the decrease of the group load. In order to ensure that the steam supply pressure requirements are met at low loads, it is necessary to throttle and reduce the pressure of high-pressure extraction steam at high loads. There is a function force loss

Moreover, for high-pressure heating of about 5MPa, in order to meet the low-load pressure requirements, it is necessary to throttle from the main steam (high-load about 25MPa); (High load about 6MPa) throttling, so there is a large throttling loss

[0005] For the back-pressure unit that uses the steam turbine exhaust steam of the back-pressure unit to supply heat to the outside, the main problems are: first, the power generation of the unit changes with the heat supply, and the power generation decreases when the heat supply decreases. The generator set shuts down during heating; secondly, the power generation capacity of the back pressure unit is small, and the largest back pressure unit in China is about 80MW, which is far lower than the conventional once-reheated condensing steam generator set (300~1000MW)

Therefore, the investment is large, and there is a certain degree of waste at the same time

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