Steam secondary reheating system

Abstract

The invention provides a steam secondary heating system. The system comprises a steam turbine and a secondary reheater, wherein the steam turbine comprises a high-pressure cylinder, intermediate-pressure cylinders and a low-pressure cylinder which are connected in sequence; the secondary reheater is arranged on the exterior of a boiler, and is connected with the exhaust port of one intermediate-pressure cylinder of the steam turbine and the air inlet of the other intermediate-pressure cylinder or the low-pressure cylinder of the steam turbine; the secondary reheater produces high-temperature reheated steam, and introduces the high-temperature reheated steam into the other intermediate-pressure cylinder or the low-pressure cylinder. According to the steam secondary reheating system provided by the invention, the investment on the secondary reheating system is greatly reduced while the efficiency is improved, so that the steam secondary reheating system has the advantages of excellent investment income and technique economical efficiency.

Description

technical field [0001] The present invention relates to a kind of electric equipment, especially relates to a kind of novel steam secondary reheating system. Background technique [0002] In conventional thermal power plants, reheat can be used to increase the efficiency of the thermodynamic cycle. Among them, reheating means that the steam that has done part of the work in the steam turbine is led out for reheating, and then led back to the steam turbine to continue to work. Through reasonable reheating, the exhaust humidity can be reduced and the thermal cycle efficiency can be improved. [0003] Generally, more reheating times lead to higher thermal cycle efficiency, but at the same time, the cost is also high. Therefore, most thermal power plants use the boiler primary reheat system, and only a few thermal power plants use the boiler secondary reheat system. [0004] A main factor for the high cost of the secondary reheat system of conventional boilers is the low press...

AI Technical Summary

Problems solved by technology

[0004] A main factor for the high cost of the secondary reheat system of conventional boilers is the low pressure, high temperature, low steam density, and large volume flow of the second-stage reheating of the flue gas-steam heat exchange. Not only the second-stage reheating heating surface of the boiler Large, medium-pressure cylinder for second-stage reheating of the steam turbine has a large flow volume and high equipment cost, and the corresponding requirements for the second-stage reheating pipe are large in size, and the distance from the boiler to the steam turbine is long. The second stage between the steam turbine and the boiler The pipeline for reheating back and forth is long, and the cost of the pipeline is correspondingly high

In addition, the long back and forth pipelines lead to large flow resistance, which affects the thermal cycle efficiency

These factors lead to the poor return on investment of the conventional boiler secondary reheating system, which cannot be promoted

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