Method for flexibly controlling air excess coefficient of impulse burner

Abstract

The invention discloses a method for flexibly controlling the air excess coefficient of an impulse burner. The air-fuel ratio of a whole impulse heating furnace is controlled according to manifold air and gas pressure in three modes: 1) a low-temperature mode; 2) a high-temperature non-full load mode; and 3) a high-temperature full load mode. In the low-temperature mode, the furnace temperature is lower than 800 DEG C, the whole furnace is controlled, and the opening time of a gas cut-off valve is as same as that of an air cut-off valve. In the high-temperature non-full load mode, the furnace temperature is higher than or equal to 800 DEG C, the demand on heat load is lower than or equal to 90%, the gas cut-off valve is controlled to delay opening time sequence and time when the air excess coefficient is larger than 1, and the air cut-off valve is controlled to bring opening time sequence and time forward when the air excess coefficient is smaller than 1. In the high-temperature full load mode, the furnace temperature is higher than or equal to 800 DEG C, the demand on the heat load is higher than 90%, the opening time sequence and time of the gas cut-off valve is forcedly controlled when the air excess coefficient is larger than 1, and the opening time sequence and time of the air cut-off valve is forcedly controlled when the air excess coefficient is smaller than 1. The air excess coefficient of each impulse area of the impulse heating furnace can be automatically and stably controlled.

Description

technical field [0001] The invention relates to a steel slab pulse heating furnace combustion technology, in particular to a method for flexibly controlling the air excess coefficient of a pulse burner. Background technique [0002] The air excess coefficient is an important control parameter in the combustion process of the heating furnace. It refers to the ratio of the actual supplied air volume to the theoretically required air volume. important influence. At present, many domestic steel mills are building or renovating pulse heating furnaces, transforming the original traditional combustion technology into pulse combustion technology. Since the combustion system of the pulse heating furnace only has the air and gas pressure regulating valves in the main pipe to adjust the air and gas pressure, and there is no air and gas flow regulating valves in each control section like the traditional heating furnace, at present, it can only be used for the whole furnace. The air-f...

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Problems solved by technology

Since the combustion system of the pulse heating furnace only has the air and gas pressure regulating valves in the main pipe to adjust the air and gas pressure, and there is no air and gas flow regulating valves in each control section like the traditional heating furnace, at present, it can only be used for the whole furnace. The air-fuel ratio (referring to the ratio of the air volume to the gas volume when the theoretical full combustion is ensured) is adjusted, that is, the same air-fuel ratio control is performed on all the pulse burners of the whole furnace through the control of the air and gas pressure regulating valve of the main pipe, so There is no way to accurately control the excess air coefficient of each pulse burner

Although some pulse heating furnaces retain the flow regulating valves of each section of the traditional heating furnace to adjust the air and gas flow, this method is susceptible to pressure fluctuations in the main pipe gas and pulse combustion characteristics. Gas and air pressure fluctuate, and its air-fuel ratio control, especially the control of excess air coefficient, cannot respond quickly and accurately, which affects the demand for excess air at different positions in the furnace for different types of steel, and hinders the control of pulse heating furnaces flexibility

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