Economizer increasing fume temperature at SCR inlet by changing areas and flowing modes

Abstract

The invention discloses an economizer increasing the fume temperature at an SCR inlet by changing areas and flowing modes. A bypass is arranged on a water supply pipe connected with an economizer inlet header and is divided into two branch pipes, the first branch pipe is connected with economizer coiler headers, and the second branch pipe is directly connected with an economizer outlet header. Stop valves and flow regulating valves are sequentially arranged in the two branch pipes in the flowing direction of fluid correspondingly. The heating areas of economizer sets are regulated by regulating the valves of the first branch pipe, so that the heat exchange amount of an economizer system is reduced so as to control the fume temperature at an economizer outlet; and the flowing modes of fume and water are changed by regulating the valves of the second branch pipe, the low-load working condition which does not reach the SCR operation condition originally can meet the temperature requirement of SCR operation, and the continuous operation time of a power plant SCR denitration system is effectively prolonged. The activity of an SCR catalyst is improved due to increase of the fume temperature in the SCR system under the low-load working condition, so that the denitration capacity of the SCR system is improved.

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 ...

AI Technical Summary

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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