Natural circulating drum boiler with smoke temperature rising system

Abstract

The invention relates to a natural circulating drum boiler with a smoke temperature rising system. The natural circulation drum boiler comprises a boiler body, a steam drum, a coal economizer, an SCR reactor, an air pre-heater and the smoke temperature rising system. A downcomer of the steam drum is connected with a low water drum of the boiler body. The temperature rising system is composed of a water pump, a switch valve and an electric adjusting valve. The low water drum of the boiler body is connected with an inlet pipe of the water pump through the switch valve, and an outlet pipe of the water pump is connected with a water feeding inlet pipe of the coal economizer in parallel through the electric adjusting valve. A check valve is connected between an outlet of the water pump and the electric adjusting valve. The smoke temperature rising system is applicable to subcritical and ultra-high pressure natural circulation drum boilers, the SCR reactor can be made to run normally under the conditions / condition of low loads and / or low atmosphere temperature, and therefore the smoke emission quality of the subcritical and ultrahigh pressure natural circulation drum boilers under the conditions / condition of the low loads and / or the low atmosphere temperature can reach national standards.

Description

technical field [0001] The invention relates to a natural circulation drum boiler for power generation, in particular to a natural circulation drum boiler capable of increasing the inlet smoke temperature of an SCR reactor of the natural circulation drum boiler. Background technique [0002] China's energy structure is dominated by coal, and coal consumption will continue to grow. According to statistics, thermal power installed capacity accounts for more than 74% of China's installed power generation capacity. For a long time to come, nitrogen oxide pollution caused by coal burning will be another important environmental problem after sulfur dioxide pollution. At the same time, the "Emission Standard of Air Pollutants for Thermal Power Plants (GB13223-2011)" implemented in January 2011 has reduced the maximum allowable emission concentration limit of nitrogen oxides from power plant boilers to 100~200mg / m 3 It has become a standard configuration for coal-fired power genera...

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Problems solved by technology

[0009] In order to solve the technical problem that the SCR reactor cannot be put into operation under the condition of low load and / or low atmospheric temperature of the natural circulation drum boiler, the present invention provides a natural circulation drum boiler with a flue gas heating system. The water system of some natural circulation drum boilers is transformed, and the water pump is used to transport the high-temperature saturated water that enters the lower water drum of the boiler from the downcomer of the steam drum to the water side inlet of the boiler economizer to mix with the feed water of the economizer to improve coal saving The temperature of the feed water of the boiler economizer can be increased to increase the flue gas temperature at the outlet of the boiler economizer so that the temperature can reach the applicable temperature for the SCR reactor to be put into operation

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