Low-nitrogen combustion method for radiant tube heating system

Abstract

The invention relates to a low-nitrogen combustion method for a radiant tube heating system, and belongs to the technical field of low-nitrogen combustion, the air inlet end and the air outlet end of a radiant tube burner are connected with an air pipeline system and a smoke exhaust pipeline system respectively, and the smoke exhaust pipeline system is connected back to the air pipeline system through a flow regulating valve with a cut-off function. A NOx detection unit is arranged on the smoke exhaust pipeline system, an oxygen detection unit is arranged on the air pipeline system, a NOx emission target value is set, a combustion-supporting gas oxygen concentration set value is adjusted through a NOx detection value, and the opening degree of a flow adjusting valve with a cut-off function is adjusted through an oxygen detection value. Part of combustion waste gas enters the air pipeline system, the oxygen concentration of combustion-supporting air is reduced, the combustion intensity is reduced, and nitric oxides are reduced; and external flue gas circulation amount is controlled by the NOx detection value in a linkage manner, so that unnecessary increase of external flue gas circulation is avoided, and energy waste is reduced. The method can be widely applied to combustion systems with a high heat value, small combustion space, high heat intensity and high nitrogen oxide control difficulty.

Description

technical field [0001] The invention belongs to the technical field of low-nitrogen combustion, and relates to a low-nitrogen combustion method for a radiant tube heating system. Background technique [0002] In the heat treatment process of the steel production process, many links need to be carried out under a special furnace atmosphere, and radiant tubes must be used for indirect heating. In the radiant tube indirect heating system, the combustion space is severely limited and relatively closed, and the requirements for combustion technology are extremely high. Low-nitrogen combustion technologies such as conventional internal flue gas circulation / air gas staged combustion are difficult to adapt to, and the nitrogen reduction effect is very poor. Obviously; if the overall out-of-stock outside the furnace is used, there will be problems such as high operating costs. [0003] In the existing technology, the external circulation of flue gas is usually mixed with air to part...

AI Technical Summary

Problems solved by technology

In the radiant tube indirect heating system, the combustion space is severely limited and relatively closed, and the requirements for combustion technology are extremely high. Low-nitrogen combustion technologies such as conventional internal flue gas circulation / air gas staged combustion are difficult to adapt to, and the nitrogen reduction effect is very poor. Obviously; if the overall out-of-stock outside the furnace is used, there will be problems such as high operating costs

[0003] In the existing technology, the external circulation of flue gas is usually mixed with air to participate in combustion to achieve low nitrogen emission. However, the amount of external circulation of flue gas is not controlled, and there are technologies such as high exhaust temperature of the system and large exhaust heat loss. question

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