Optimum scheme of ultra-supercritical secondary reheating unit

Abstract

The invention discloses an optimum scheme of an ultra-supercritical secondary reheating unit, and refers to a secondary reheating unit of a coal-fired power plant after optimization of a back heating system, parameter optimization of main steam, primary reheating steam, and secondary reheating steam, and structural optimization of a turbine body. The optimum scheme of the ultra-supercritical secondary reheating unit can obviously reduce the heat loss of the secondary reheating unit, and significantly decrease greenhouse gas emission and decreases cost of the ultra-supercritical secondary reheating unit obviously. By taking a 1200 MW grade unit as an example, four mono-axial cylinders are used for gas exhausting, the ultra-supercritical secondary reheating unit is composed of a single-flow ultra-high pressure cylinder capable of completely supplying water, back-heating and pumping gas, a dual-flow high and medium pressure cylinder, and two dual-flow middle and low pressure cylinders; there is no middle pressure cylinder and a middle low pressure linking pipe; no gas pumping opening is arranged on the high middle pressure cylinder and the middle low pressure cylinder; the water supply and back heating are provided by a first pump, a new second pump, a new third pump, and a new fourth pump; a ultra-low temperature coal economizer, and a heat primary wind condensing water heater replace a seventh pump, an eighth pump, a ninth pump, and a tenth pump to heat the condensed water; all low-pressure heaters are canceled.

Description

(1) Technical field: [0001] The optimization scheme of an ultra-supercritical double reheating unit of the present invention relates to a coal-fired power plant secondary heat generating unit optimized through recovery system optimization, parameter optimization of main steam, primary reheat steam, and secondary reheat steam, and optimization of steam turbine body structure. The reheat unit can significantly reduce the heat consumption of the double reheat unit, significantly reduce greenhouse gas emissions and significantly reduce the cost of the ultra-supercritical double reheat unit. (two) background technology: [0002] The design values ​​of the main steam temperature / primary reheat steam temperature / secondary reheat steam temperature of the typical turbine-side main steam temperature / primary reheat steam temperature of the existing double reheat steam turbine generator set are 600°C / 620°C / 620°C; the main steam pressure / The design value of primary reheat steam pressure...

AI Technical Summary

Problems solved by technology

[0017] When the secondary reheat temperature is constant, the exhaust humidity of the final blade of the low-pressure cylinder is related to the level of the secondary reheat pressure. Reheat pressure, that is, the secondary reheat pressure is determined by the exhaust steam humidity of the last stage blade of the low-pressure cylinder. In this way, the effective enthalpy drop of the high-pressure cylinder is often significantly compressed, and the heat absorption of the secondary reheat system is also limited.

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