Low-pressure cylinder switching and full-load heat supply method and system with built-in injection pressurizing pipe bundle

Abstract

The invention discloses a low-pressure cylinder switching and full-load heat supply method and system with a built-in injection pressurizing pipe bundle, and belongs to the technical field of combinedheat and power generation and centralized heat supply. A low-pressure group injection pipe bundle is arranged in a cavity of a waste steam communicating pipe between a low-pressure cylinder and a condenser of a combined heat and power generation system, a high-pressure driving steam inlet of the low-pressure group injection pipe bundle communicates with a steam exhaust port of a medium-pressure cylinder, a low-pressure inlet is formed in the upper part of the waste steam communicating pipe, medium-pressure exhaust steam is arranged in an area in front of a waste steam inlet of the condenser,a cooling water inlet and a cooling water outlet of the condenser communicate with a heat supply network return water inlet pipe and a heat supply network return water outlet pipe correspondingly andpreheat heat supply network water, and an integrated device composed of the waste steam communicating pipe, the low-pressure group injection pipe bundle in the waste steam communicating pipe, the condenser, a low-pressure bypass system in front of a steam inlet of the low-pressure cylinder and the like can achieve various working modes such as low-pressure cylinder switching, near-full-load powergeneration of the low-pressure cylinder and full-load heat supply through waste steam waste heat through automatic adjustment. According to the low-pressure cylinder switching and full-load heat supply method and system with the built-in injection pressurizing pipe bundle, upgrading and updating are carried out on original low-pressure cylinder switching, rotor replacing, absorption type heat pumpheat supply and the like, and the operation flexibility of thermal power is improved.

Description

technical field [0001] The invention relates to a low-pressure cylinder cut-out and full-load heating method and system with a built-in ejector booster tube bundle, and belongs to the technical field of heat and power cogeneration and waste heat recovery heat supply. Background technique [0002] Due to the inherent characteristics of thermoelectric coupling in the traditional cogeneration system of thermal power plants, it usually adopts the operation mode of setting power by heat or heat by electricity. In view of the fact that the current power supply is much higher than the power demand, the National Energy Administration has issued a number of policies Measures to promote thermoelectric decoupling, deep peak regulation, and flexibility transformation of thermal power generation. Many power plants also take measures to maximize heating capacity and minimize cold end losses. Existing thermoelectric decoupling and measures to increase heating capacity include: heat storag...

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Problems solved by technology

Existing thermoelectric decoupling and measures to increase heating capacity include: heat storage schemes, electric boiler schemes, which occupy a large area and have a large investment scale, and cannot be fully decoupled in depth; zero-effort transformation of low-pressure cylinders, including optical axis schemes, and The scheme of directly reducing or closing the steam intake of the low-pressure cylinder, and introducing a small amount of cooling steam to cool the final stage and the exhaust port has little effect on increasing the heat supply; the scheme of combined steam distribution of high and low bypass, the problem lies in low power generation At the load rate, the inlet steam pressure of the reheater is greatly reduced due to the substantial reduction of the steam intake of the turbine, so that the volume flow rate is greatly increased, and the flow capacity and heat transfer capacity of the reheater are greatly reduced, making it difficult to effectively reduce the smoke temperature of the reheater , leading to overheating and damage to the reheater and subsequent heating surfaces; cylinder drilling and low vacuum circulating water heating cannot effectively reduce the power generation load rate; the low vacuum circulating water heating scheme often used by small steam turbines can be Eliminate cold end loss, but limited by the operation safety of the last stage blades of the steam turbine, the temperature of the inlet and outlet water is strictly limited, and the temperature of the water supply usually does not exceed 55°C; the high back pressure heating solution of large steam turbines needs to replace the rotor, operation and maintenance management The workload has increased significantly, and there are potential security issues, etc.

[0003] Using ejector steam pressure matching technology and ejector heat pump exhaust heat recovery technology, a complete thermoelectric decoupling scheme can be realized, including: ejector steam distribution thermoelectric decoupling method based on axial thrust balance and reheat balance ( Application No. 203110733266), heat supply method and system based on complete thermoelectric decoupling of ejector heat pump exhaust steam recovery (application No. 20311072833, a thermoelectric decoupling system based on multi-stage ejector steam distribution and heat pump exhaust steam recovery (patent No. 20323003781), an injection steam distribution deep thermoelectric decoupling system based on axial thrust balance (patent No. 20323003796), etc., which can realize thermoelectric decoupling at a large scale or even near full load, but in the thermoelectric decoupling link of the low-pressure cylinder , not only to ensure the minimum cooling condition of the low-pressure cylinder, but also to realize the recovery of waste heat from exhausted steam of the low-pressure cylinder and to eliminate the loss of the cold end. The ejector heat pump technology is adopted, but in view of the fact that the exhaust gas of the low-pressure cylinder is often large and its specific volume And the volume flow rate is very large. For the wet cooling unit, it is necessary to use large-diameter pipes to lead the exhaust steam to the place where the low-pressure ejector and heating heater are installed. Because the installation and maintenance space of the steam turbine room is usually compact, it is difficult to have space for piping. Therefore, it is more suitable for air-cooled units rather than wet-cooled units, and the entire ejector heat pump system including ejector and heating heat exchanger occupies a relatively large area and investment

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