Corrosion protection technology for shutdown and standby of thermal system of gas-steam combined cycle unit

Abstract

The invention discloses a corrosion prevention technology of combustion gas-steam combined cycle unit thermal system standby. The corrosion prevention technology comprises a combustion gas-smoke system dry-air protection technology and an afterheat unit moisture system dry-air combined protection technology; the combustion gas-smoke system dry-air protection technology adopts a low-humidity dry-air aeration-drying scheme; the afterheat unit moisture system dry-air combined protection technology adopts a protection scheme combining chemical corrosion inhibition with dry-air drying; and the afterheat unit moisture system dry-air combined protection technology comprises the following four steps of afterheat drying, corrosion inhibitor protection, aeration drying and humidity maintenance. Thecorrosion prevention technology completely adapts to the characteristics of the structure, the operation mode, frequent standby and uncertain outage time of a combustion gas-steam combined cycle unitthermal system, total-system and total-period corrosion prevention of the thermal system in the outage state can be achieved, equipment corrosion during outage is controlled to the greatest extent, and the corrosion prevention technology has the remarkable advantages such as wide application scope, flexible operation, economy, environmental protection and the like.

Description

technical field [0001] The invention belongs to the technical field of equipment corrosion protection, and relates to the corrosion protection of metal materials of a thermal power generating set, in particular to an anti-corrosion protection process during the standby period of the thermal system of a gas-steam combined cycle generating set. Background technique [0002] When the thermal equipment in the standby state is in contact with the air when the interior is humid, a wide range of oxygen corrosion will occur. Without suitable anti-corrosion measures, the surface of the equipment material will be corroded and damaged, the strength will be reduced, and the equipment will be scaled. , thermal systems that are often out of service or long-term outages, outage corrosion will seriously affect the safety and economy of thermal equipment, equipment corrosion protection in the standby phase has always been an important task for all thermal units. Due to the particularity of t...

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Problems solved by technology

The protective liquid method can only be applied in seasons or areas that do not need antifreeze, and the scope of protection is limited to the sealable boiler body and water supply system pipes, and cannot be used for steam turbines, condenser equipment, and gas-flue gas systems; in addition, this method produces A large amount of waste liquid containing ammonia nitrogen has certain environmental risks

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