System and method for supplying heat by aid of exhaust steam of steam turbines

Abstract

The invention discloses a system and a method for supplying heat by the aid of exhaust steam of steam turbines. The system comprises a heat network primary heater and a heat network secondary heater.The heat network primary heater and the heat network secondary heater are serially connected with each other and are used for heating het network return water, a steam injector is communicated with aheat source inlet of the heat network primary heater via a first pipeline, a steam turbine steam exhaust pipeline is communicated with an inlet in one end of the steam injector via a steam exhaust pipeline, and a steam extraction heat supply pipeline of a thermal power plant unit is communicated with an inlet in the other end of the steam injector via an injection pipeline; an outlet end of the steam extraction heat supply pipeline is further directly communicated with a heat source inlet of the heat network secondary heater via a second pipeline; two drain pipelines are arranged at the bottomof the heat network primary heater and the bottom of the heat network secondary heater and return a thermodynamic system after joining with each other. The system and the method have the advantages that the low-grade exhaust steam of the steam turbines can be injected by high-grade steam, accordingly, the heat supply areas can be enlarged under the condition of identical heat supply steam quantities, system cold-end loss can be reduced, the power generation can be increased, and coal consumption can be lowered.

Description

technical field [0001] The invention relates to the technical field of steam turbine power generation in a thermal power plant, in particular to a system and method for heat supply using exhaust steam from a steam turbine. Background technique [0002] At present, most of the central heating methods in northern my country are cogeneration systems of thermal power plants, which extract part of the steam that has done work in the steam turbine to exchange heat with the return water of the heating pipe network to release the latent heat of vaporization. The temperature of the heating steam in the same type of heating unit is mostly above 250°C, while the water temperature required for the primary water supply of the heating network is generally 110-130°C. From the perspective of heat transfer, although the heat transfer temperature difference is increased, the heat transfer is enhanced. ; However, the large heat transfer temperature difference also leads to a large irreversible...

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Problems solved by technology

[0004] In thermal power units, steam turbine exhaust is a low-grade waste heat, but it contains a large amount of latent heat of vaporization. This part of waste heat is usually difficult to use, but is directly lost to the environment, causing a large loss at the cold end of the system, but If the exhaust steam is heated separately to heat the return water of the heating network, it will have little effect due to its low grade

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