Annealing furnace inside atmosphere control method and system

Abstract

The invention discloses an annealing furnace inside atmosphere control method which comprises the following steps of according to the historical production data of an annealing furnace under the stable working condition, analyzing to obtain a relation table of annealing furnace heating section excess air coefficients and preheating section smoke gas oxygen contents; judging whether an annealing furnace heating schedule is changed or not; and if not, monitoring the annealing furnace preheating section smoke gas oxygen content through an oxygen content analyzer, comparing with the relation table, and adjusting the annealing furnace heating section excess air coefficient. According to the annealing furnace inside atmosphere control method provided by the invention, the non-oxidation section furnace inside atmosphere fluctuation caused by the coal gas caloric value change or the coal gas pressure fluctuation is timely and effectively solved, the non-oxidation section furnace inside weaklyreducing atmosphere is ensured to run stably, and meanwhile, the coal gas is sufficiently utilized through the feedforward control on the preheating section air amount, so that the energy is saved.

Description

technical field [0001] The invention relates to the technical field of combustion control of an annealing furnace, in particular to a method and system for controlling the atmosphere in an annealing furnace. Background technique [0002] The hot-dip galvanizing annealing furnace is one of the most important equipment on the hot-dip galvanizing unit, mainly used for annealing the strip steel. The annealing quality of the cold-rolled strip plays a vital role in the properties of the strip after hot-dip galvanizing. The improved Sendzimir hot-dip galvanizing annealing furnace usually consists of a non-oxidizing section, a reducing section, a slow cooling section, and a fast cooling section. After the steel strip undergoes rapid temperature rise in the non-oxidizing section, recrystallization annealing in the reducing section, heat preservation, slow cooling and rapid cooling, it enters the zinc pot for galvanizing through the furnace nose. The front part of the non-oxidation ...

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Problems solved by technology

Domestic research has shown that in order to ensure the quality of galvanizing, the atmosphere in the non-oxidizing section of the furnace should be weakly reducing to eliminate free oxygen in the flue gas, so that the oxidizing gas and reducing gas (such as CO 2 / CO,H 2 O / H 2 ) is within a reasonable range, but in actual production, the calorific value or gas pressure of the gas fluctuates, and the actual air supply cannot be adjusted in real time, which will lead to excessive oxidative components in the furnace. Traditionally used It is manual adjustment, which has great untimelyness and blindness, and the resulting quality defects are also obvious, and it is difficult to meet the requirements of lean production

At present, the solution generally adopted by domestic and foreign production enterprises is to install an off-line furnace composition analyzer in the non-oxidation section, but due to the lagging test results, it cannot be used for real-time automatic control of the burners in the heating section, and the burners can only be adjusted manually by the operator Combustion Air Excess Coefficient

When the gas calorific value changes or the gas pressure fluctuates, the gas calorific value change cannot be known in advance, and the resulting consequences are difficult to monitor directly, resulting in untimely, blind, intermittent manual operations, and poor stability and fluctuations in the atmosphere in the furnace. Large, high energy consumption and uncontrolled quality

Even if an online gas calorific value analyzer is installed, there is still a detection lag, and it also provides a basis for the theoretical air excess coefficient, which does not fully represent the actual combustion situation

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