Method and system for start-up and commissioning of newly built supercritical unit by using external steam

Abstract

The invention discloses a method and a system utilizing external steam for start debugging of a new-built supercritical unit. The method comprises steps as follows: a first isolation gate is additionally mounted between a high-pressure bypass valve I and a reheat cooling section I of a production unit, a communication pipeline is additionally mounted at an isolation section between the high-pressure bypass valve I and the reheat cooling section I of the production unit, a communication gate is arranged on the communication pipeline, and a second isolation gate is additionally mounted between a high-pressure bypass valve II and a reheat cooling section II of the new-built supercritical unit; the first isolation gate is closed, the communication gate is opened, and external steam after temperature and pressure reduction is supplied to the new-built supercritical unit by the high-pressure bypass valve I of production unit; a superheater and a connecting pipeline are purged under the reduced pressure by means of the external steam, and a reheater and a connecting pipeline are purged under stable pressure and reduced pressure by means of the external steam; overall start debugging of a turbine of the new-built supercritical unit is performed. Under the condition that a boiler of the new-built unit is not ignited, steam purging of the units and overall start debugging work of the no-load test operation stage are completed by the aid of the external steam provided by the production unit, so that the ignition times of the boiler in the supercritical unit and time of operation in a non-economic area are reduced.

Description

technical field [0001] The invention relates to the field of thermal coal-fired power generation units, in particular to a method and system for starting and debugging a newly built supercritical unit by using external steam. Background technique [0002] During the blowpipe and no-load trial operation stage of the new supercritical unit, a large number of equipment needs to be started and stopped repeatedly, and the steam-water system needs to be washed repeatedly. Cost and environmental protection caused great pressure. [0003] The existing start-up and commissioning methods for newly-built units are as follows: 1. The start-up and commissioning of most supercritical units is based on the idea of ​​a unit unit, igniting the boiler to self-produce steam, and sequentially completing hot flushing, steam blowing, steam turbine running, electrical External steam is only used as an auxiliary steam source for start-up and commissioning projects such as test and generator grid c...

AI Technical Summary

Problems solved by technology

[0002] During the blowpipe and no-load trial operation stage of the newly-built supercritical unit, a large number of equipment needs to be started and stopped repeatedly, and the steam-water system needs to be washed repeatedly. Great pressure on cost and environmental protection

[0003] The existing start-up and commissioning methods for newly-built units are as follows: 1. The start-up and commissioning of most supercritical units is based on the idea of ​​a unit unit, igniting the boiler to self-produce steam, and sequentially completing hot flushing, steam blowing, steam turbine running, electrical External steam is only used as an auxiliary steam source for start-up and commissioning projects such as test and generator grid connection with load; 2. A small number of power plants have added a system for extracting cold re-steam from adjacent machines to heat feed water, realizing the completion of supercritical units without igniting the boiler The hot flushing work has good energy saving and environmental protection benefits, but due to the limited amount of cold re-extraction steam, the steam parameters cannot be adjusted flexibly, and cannot meet the needs of more trial operation conditions

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