WO2022156282A1 - Protective gas supply system of annealing furnace for cold rolling - Google Patents

Abstract

The present invention relates to a protective gas supply system of an annealing furnace for cold rolling. The protective gas supply system may comprise a liquid argon gasifying device and a waste argon recycling device, argon generated by the liquid argon gasifying device is supplied to the annealing furnace for cold rolling through a first pipeline, and argon generated by the waste argon recycling device is supplied to the annealing furnace for cold rolling through a second pipeline. By replacing hydrogen with an inert gas, namely the argon, the occurrence of blast accidents can be avoided, hydrogen production costs are reduced, and solid waste pollutions in the hydrogen production process are avoided; moreover, waste argon is recycled, thereby remarkably reducing the consumption of argon, reducing production costs of strip steel, improving enterprise competitiveness, and achieving important significance for energy conservation and consumption reduction of cold rolling steps of ferrous metallurgy enterprises.

Description

A protective gas supply system for cold rolling annealing furnace technical field

The invention relates to an iron and steel cold-rolling annealing furnace, in particular to a protective gas supply system for the cold-rolling and annealing furnace.

Background technique

Cold rolling annealing furnaces in iron and steel metallurgical enterprises often use high-purity hydrogen as protective gas, and the protective gas after use is discharged as exhaust gas. The production cost of hydrogen is relatively high, and the production environment safety level is required to be higher; the hydrogen content in the exhaust gas after use is as high as 80%, and the direct emission is not only a great waste of energy, but also causes certain pollution to the environment. May bring security risks.

SUMMARY OF THE INVENTION

The present invention aims to provide a protective gas supply system for a cold rolling annealing furnace to solve the above problems. For this reason, the concrete technical scheme that the present invention adopts is as follows:

A protective gas supply system for a cold rolling annealing furnace, which can include a liquid argon gasification device and a waste argon recovery and recycling device, the argon generated by the liquid argon gasification device is supplied to the cold rolling annealing furnace through a first pipeline, The argon generated by the waste argon recovery and recycling device is supplied to the cold rolling annealing furnace through the second pipeline.

Further, the liquid argon gasification device includes a liquid argon storage tank, an air temperature type vaporizer and a pressure regulating valve group, and the liquid outlet pipe of the liquid argon storage tank is connected to the inlet of the air temperature type vaporizer , the outlet of the air-temperature vaporizer is connected to the first pipeline, and the pressure regulating valve group is installed on the first pipeline.

Further, two sets of the liquid argon storage tank, the air-temperature vaporizer and the pressure regulating valve group are arranged in parallel.

Further, the waste argon recovery and recycling device includes a pretreatment tower, a pressurizing fan, a deaerator and a drying tower connected in sequence through corresponding pipelines. The argon discharge pipe is connected for physical adsorption to remove emulsion, moisture and particles in waste argon, the pressurizing fan is used for pressurizing the pretreated argon, and the deaerator is used for argon The argon gas is deoxidized so that the oxygen content in the argon gas is less than 5 ppm, and the drying tower is used to further remove the moisture in the argon gas, so that the dew point of the argon gas is lower than -60°C.

Further, two sets of the pretreatment tower, the pressurized fan and the drying tower are arranged in parallel.

Further, the pretreatment tower is provided with multilayer molecular sieves and/or activated carbon.

Further, the air inlet of the pretreatment tower is located at the bottom, the air outlet is located at the top, and the molecular sieve is arranged below the activated carbon.

Further, the pressurized fan is provided with a backflow adjustment facility to ensure a stable furnace pressure in the annealing furnace.

Further, the deaerator is filled with catalyst and deoxidizer.

Further, the drying tower is filled with multilayer molecular sieves to adsorb residual water and carbon dioxide.

The present invention adopts the above technical scheme, and has the beneficial effects as follows: the use of inert gas argon to replace hydrogen can avoid the occurrence of explosion accidents, reduce the cost of hydrogen production, and avoid the solid waste pollution in the hydrogen production process; The recovery and utilization of argon significantly reduces the consumption of argon gas, reduces the production cost of strip steel, and improves the competitiveness of enterprises.

Description of drawings

To further illustrate the various embodiments, the present invention is provided with the accompanying drawings. These drawings are a part of the disclosure of the present invention, which are mainly used to illustrate the embodiments, and can be used in conjunction with the relevant description of the specification to explain the operation principles of the embodiments. With reference to these contents, one of ordinary skill in the art will understand other possible embodiments and advantages of the present invention. Components in the figures are not drawn to scale, and similar component symbols are often used to represent similar components.

FIG. 1 is a process flow diagram of the cold rolling annealing furnace shielding gas supply system of the present invention.

Detailed ways

The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

As shown in FIG. 1 , a protective gas supply system for a cold rolling annealing furnace may include a liquid argon gasification device 1 and a waste argon recovery and recycling device 2 . The argon generated by the liquid argon gasification device 1 is supplied to the cold rolling annealing furnace through the first pipeline A, and the argon generated by the waste argon recovery and recycling device 2 is supplied to the cold rolling annealing furnace through the second pipeline B. That is, the purified recycled argon gas and the argon gas vaporized from the liquid argon tank are sent into the annealing furnace in parallel, and the two argon gas can be switched for use.

The liquid argon gasification device 1 may include a liquid argon storage tank 11 , an air temperature gasifier 12 and a pressure regulating valve group 13 which are connected by pipelines in sequence. Specifically, the liquid outlet pipe of the liquid argon storage tank 11 is connected to the inlet of the air temperature type vaporizer 12, the outlet of the air temperature type vaporizer 12 is connected to the first pipeline A, and the pressure regulating valve group 13 is installed in the first pipeline A. on a pipeline A. The liquid argon in the liquid argon storage tank 11 is vaporized into argon gas through the air temperature gasifier, and then directly sent to the cold rolling annealing furnace after passing through the pressure regulating valve group 13 as a protective gas for strip production. Among them, the liquid argon storage tank 11, the air temperature type vaporizer 12 and the pressure regulating valve group 13 are all set in parallel in two sets, which are backup for each other, and can also be used at the same time, ensuring the continuous and stable supply of argon.

A liquid level gauge 111 is installed on the liquid argon storage tank 11, and the liquid argon amount in the liquid argon storage tank 11 can be known through the liquid level gauge 111, so as to facilitate timely replenishment and ensure a continuous and stable supply of argon gas. In a specific embodiment, the volume of the liquid argon storage tanks 11 is 20 cubic meters, and there are two liquid argon storage tanks 11, which can satisfy the supply of protective argon gas of 200Nm3/h for ~6 days. Preferably, the outer wall of the liquid argon storage tank 11 is covered with a thermal insulation layer.

With the continuous progress of the annealing process, the composition, oxygen content, dew point and impurity particle size of the argon gas in the furnace will change accordingly. It will contain a small amount of impurities such as oxygen, nitrogen, water vapor, and emulsion, and its quality cannot be used as a protective gas. . Therefore, it needs to be purified by the waste argon recovery and recycling device 2 .

The waste argon recovery and recycling device 2 includes a pretreatment tower 21, a pressurizing fan 22, a deaerator 23 and a drying tower 24 connected in sequence through corresponding pipelines. Wherein, the air inlet of the pretreatment tower 21 is connected with the waste argon discharge pipe of the cold rolling annealing furnace. The waste argon advanced pretreatment tower 21 from the cold rolling annealing furnace undergoes physical adsorption. The pretreatment tower 21 is provided with adsorbents such as multilayer molecular sieves and/or activated carbon to remove impurities such as emulsion, moisture and particles in waste argon. Specifically, the air inlet of the pretreatment tower 21 is located at the bottom, the air outlet is located at the top, and the molecular sieve layer is arranged below the activated carbon layer. There are two pretreatment towers 21 for switching use during regeneration.

The pressurizing fan 22 is used to pressurize the pretreated argon gas to compensate for the resistance loss required by the argon gas going through the subsequent process. There are two pressurized fans 22, which are used as backup for each other. At the same time, a large reflux adjustment facility 221 is designed to prevent excessive extraction of argon in the furnace and cause pressure fluctuations in the furnace to affect strip production. The power of the pressurizing fan 22 can be adjusted as required.

The deaerator 23 is used for deoxidizing the argon, so that the oxygen content in the argon is less than 5 ppm. Specifically, the deaerator 23 is filled with a catalyst and a deoxidizer. The pressurized argon gas passes through the deaerator, and under the catalytic action of the catalyst, the oxygen in the argon gas reacts with the deoxidizer, thereby achieving the effect of removing oxygen. In a specific embodiment, the deaerator is a vertical storage tank structure with a height of about 2 meters and a diameter of about 0.5 meters. A heater is installed inside to meet the reaction temperature, and a multi-layer nickel-chromium wire mesh is laid to place the deoxidizer for the deoxidation reaction. It can be fully carried out, and at the same time, there are inlet and outlet holes for easy loading and unloading.

The drying tower 24 is used to further remove the moisture in the argon. The air outlet of the drying tower 24 is connected to the second pipeline B. After passing through the drying tower 24, the high-purity argon gas with purity greater than 99.999%, dew point temperature lower than -60°C, and oxygen content less than 5ppm is supplied to the cold rolling annealing furnace through the second pipeline B. Two drying towers 24 are provided for switching use during regeneration. In a specific embodiment, the drying tower is a vertical storage tank structure with a height of about 1 meter and a diameter of about 0.5 meters, and a multi-layer nickel-chromium wire mesh is arranged inside to place molecular sieve packing.

This system can ensure the continuous supply of protective gas in the annealing furnace. When the waste argon recovery and recycling device 2 fails to operate normally, the liquid argon gasification device 1 is put into operation; when the waste argon recovery and recycling device 2 is in normal operation, the liquid argon gasification device 1 can supplement the argon loss during the cycle, At the same time, it takes into account the role of peak regulation and voltage regulation.

The invention has strong practicability. On the one hand, it can greatly reduce the amount of argon used, reduce the operating cost of the annealing furnace, and improve the price competitiveness of the strip; The annealing furnace is required for continuous production.

Although the present invention has been particularly shown and described in connection with preferred embodiments, it will be understood by those skilled in the art that changes in form and detail may be made to the present invention without departing from the spirit and scope of the invention as defined by the appended claims. Various changes are made within the protection scope of the present invention.

Claims (10)

1. A protective gas supply system for a cold rolling annealing furnace is characterized in that it includes a liquid argon gasification device and a waste argon recovery and recycling device, and the argon generated by the liquid argon gasification device is supplied to the cold rolling annealing device through a first pipeline. Furnace, the argon gas generated by the waste argon recovery and recycling device is supplied to the cold rolling annealing furnace through the second pipeline.
2. The protective gas supply system for a cold rolling annealing furnace according to claim 1, wherein the liquid argon gasification device comprises a liquid argon storage tank, an air temperature gasifier and a pressure regulating valve group, and the liquid argon storage tank The liquid outlet pipe of the tank is connected to the inlet of the air temperature type vaporizer, the outlet of the air temperature type vaporizer is connected to the first pipeline, and the pressure regulating valve group is installed on the first pipe on the way.
3. The protective gas supply system for a cold rolling annealing furnace according to claim 2, wherein the liquid argon storage tank, the air temperature gasifier and the pressure regulating valve group are all arranged in parallel.
4. The protective gas supply system for a cold rolling annealing furnace according to claim 1, wherein the waste argon recovery and recycling device comprises a pretreatment tower, a pressurizing fan, a deaerator and a drying tower sequentially connected by corresponding pipelines , the air inlet of the pretreatment tower is connected to the waste argon discharge pipe of the cold rolling annealing furnace for physical adsorption to remove the emulsion, moisture and particles in the waste argon, and the pressurized fan is used for the pretreatment. The treated argon is pressurized, and the deaerator is used to deoxidize the argon, so that the oxygen content in the argon is less than 5ppm, and the drying tower is used to further remove the moisture in the argon, so that the Argon has a dew point below -60°C.
5. The protective gas supply system for a cold rolling annealing furnace according to claim 4, characterized in that, the pretreatment tower, the pressurizing fan and the drying tower are all arranged in parallel in two sets.
6. The protective gas supply system for a cold rolling annealing furnace according to claim 4, wherein the pretreatment tower is provided with multiple layers of molecular sieves and/or activated carbon.
7. The protective gas supply system for a cold rolling annealing furnace according to claim 6, wherein the air inlet of the pretreatment tower is located at the bottom, the air outlet is located at the top, and the molecular sieve is arranged below the activated carbon.
8. The protective gas supply system for a cold rolling annealing furnace according to claim 4, wherein the pressurized fan is provided with a backflow adjustment facility to ensure the stability of the furnace pressure of the annealing furnace.
9. The protective gas supply system for a cold rolling annealing furnace according to claim 4, wherein the deaerator is filled with a catalyst and a deoxidizer.
10. The protective gas supply system for a cold rolling annealing furnace according to claim 4, wherein the drying tower is filled with multiple layers of molecular sieves.

Images