High coke oven gas mixing air supply device of blast furnace hot blast system

Abstract

The invention relates to a high coke oven gas mixed air supply device of a blast furnace hot blast system. A blast furnace gas transmission main pipe is connected with a mixed gas transmission header pipe by a flow electrical adjustment valve; a bypass pipe is communicated with a blast furnace gas transmission main pipe and the mixed gas transmission header pipe and is formed by connecting a blast gas branch pipe, an ejector and a mixed gas branch pipe; the ejector is connected with the blast gas branch pipe through a first electrical closing valve, is connected with the mixed gas branch pipe through a second electrical closing valve, and is connected with a third electrical closing valve through a coke oven gas flow electrical adjustment valve; and the two flow electrical adjustment valves and the three electrical closing valves are connected with a central controller. The injection ratio is changed by the quantity of the blast furnace gas distributed to a bypass pipe from the blast furnace gas transmission main pipe, so that the pressure fluctuation of mixed gas is minimized; the invention not only improves the pressure lower limit value of the mixed gas, but also enhances the calorific value of the mixed gas, thereby being beneficial to the stable combustion of a hot blast furnace and optimizing the technical and economic index of the blast furnace production.

Description

technical field [0001] The invention relates to a blast furnace hot blast stove system in the field of metallurgy, in particular to a high coke oven gas mixing air supply device for the blast furnace hot blast stove system. Background technique [0002] In the field of smelting, the blast furnace hot blast stove is an important system. Its main working principle is to send the combustible gas into the hot blast stove through the pipeline, and use the combustible gas to burn the checker bricks in the furnace. After the checker bricks are heated, the combustion system is closed. And send in the cold air, use checker bricks to heat the cold air, make the air temperature after the cold air heating reach 1150 ℃ and then send it into the blast furnace. The current combustible gas mainly uses CO as the combustible component, and the calorific value is 3000kJ / m 3 The left and right blast furnace gas, due to the low calorific value of blast furnace gas, causes the average temperatur...

AI Technical Summary

Problems solved by technology

However, the pressure of blast furnace gas and coke oven gas is different. Usually, the pressure of blast furnace gas is 10-12kPa, and the pressure of coke oven gas is 4-6kPa. Blast furnace gas is the main combustible gas of hot blast stove. To the high-pressure blast furnace gas pipeline, it is necessary to solve the problem of preventing the blast furnace gas from flowing backward into the coke oven gas pipeline

At present, there are usually two solutions to prevent the backflow of blast furnace gas into coke oven gas. One is to pressurize the low-pressure coke oven gas, which requires the construction of a pressurization station, which requires a large investment in infrastructure and equipment, and high maintenance costs. The site covers a large area and the number of staff increases, all of which directly lead to an increase in production costs, and this method of pressurization has unstable pressure due to various objective factors, which is not conducive to the stable firing of hot blast stoves, and the coke oven gas The content of various organic substances is high, and using a pressurized fan to pressurize the coke oven gas will accelerate the damage of the pressurized fan, and frequent maintenance and replacement of fan parts will increase the cost of use; the other is through an ejector To mix blast furnace gas and coke oven gas, such as the "gas ejector mixer" whose publication number is CN200986189Y, the high-pressure gas delivery pipe and the low-pressure gas delivery pipe are directly connected with the ejector, and the flow rate increases when the high-pressure gas passes through the ejector The generated negative pressure inhales low-pressure gas to participate in mixing. Although this method can prevent high-pressure gas from flowing backward, the lower limit of mixed gas pressure is low. Usually, the lower limit of mixed gas pressure is only 4.5kPa, which is also not conducive to the firing of hot blast stoves.

There are two main reasons for the analysis. One is that the use of in-line pipeline diversion and backflow leads to increased resistance loss; the other is that the pressure is reduced by changing the flow rate of high-pressure gas by the ejector to approach the pressure of low-pressure gas, which will inevitably lead to the pressure of mixed combustible gas. At the same time, use the pressure at both ends of the injector to control the injection ratio. Since the injection volume is not easy to control, it is easy to cause pressure fluctuations in the mixed gas, which is also not conducive to the stable firing of the hot blast stove.

Images