A kind of economizer that changes the area and flow mode to increase the flue gas temperature at the scr inlet

Abstract

The invention discloses an economizer which changes the area and flow mode to increase the smoke temperature at the inlet of the SCR. A bypass is arranged on the water supply pipeline connected to the inlet header of the economizer. The bypass is divided into two branches, the first The branch is connected with the serpentine header of the economizer, and the second branch is directly connected with the outlet header of the economizer. In the two branch pipes, a shut-off valve and a flow regulating valve are respectively arranged in sequence along the direction of fluid flow. . Adopting the present invention is to adjust the heating area of ​​the economizer group by adjusting the first branch valve, thereby reducing the heat exchange of the economizer system to control the flue gas temperature at the outlet of the economizer; adjusting the second branch valve to change The flow mode of flue gas and water, so that the low-load working conditions that could not meet the SCR commissioning conditions can meet the temperature requirements of SCR commissioning, effectively improving the continuous operation time of the SCR denitrification system of the power plant, and the SCR denitrification system under low-load conditions. The increase of the flue gas temperature in the system leads to the increase of the activity of the SCR catalyst, which enhances the denitrification capability of the SCR system.

Description

technical field [0001] The invention relates to the field of flue gas denitrification of power station boilers, in particular to an economizer which improves the flue gas temperature at the SCR inlet by changing the area and flow mode. Background technique [0002] Selective Catalytic Reduction (SCR) denitration technology has a high denitration rate, NH 3 The escape rate is low, the operation is stable, and the maintenance is convenient. It has become a relatively mature mainstream technology for denitration in power plants at home and abroad. NO accounts for about 95% of nitrogen oxides, NO 2 accounts for about 5%, and also contains a small amount of N 2 O, when these gases are discharged into the atmosphere, they will produce acid rain, photochemical smog, ozone layer depletion and other hazards, and are one of the important sources of environmental air pollution. SCR technology is under the action of catalyst to generate harmless N 2 and H 2 O; At the same time, it ...

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Problems solved by technology

However, during the low peak period of electricity consumption, the power plant boiler operates under low load, the reaction temperature of the flue gas in the system is low, and the activity of the catalyst is reduced, resulting in a low denitrification efficiency

The denitrification system will stop running until the inlet flue gas temperature is lower than the lower limit of the system’s operating temperature, but the catalyst is still being washed by the flue gas and will continue to wear, which not only reduces the service life of the catalyst, but also fails to complete the denitrification. The purpose is to make the power station unable to meet the emission standards stipulated by the state

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