Construction and application scope of oxygen gun for tubular electric furnace

Mechanical device of tube furnace door gun
Oxygen blowing in tube furnace steelmaking is one of the important means to strengthen electric furnace smelting. The most commonly used method is to insert steel pipes into the molten pool and blow oxygen. In order to fully utilize the chemical energy in the furnace, the oxygen consumption per ton of steel has gradually increased in recent years; At the same time, considering the poor working conditions, unsafe conditions, and unstable oxygen blowing efficiency of manual oxygen blowing, a mechanical device for the electric furnace door gun has been developed. For example, the self consuming oxygen lance device developed by BSE Company in Germany and the water-cooled oxygen lance device developed by Fuchs, Berry, and Combustion Company in the United States.
Due to the consumption of a large amount of oxygen blowing pipes by self consuming oxygen guns, newly built tubular electric furnaces have been installed less frequently. The purpose of the furnace door gun device is to blow oxygen for melting aid and refining, and to blow carbon powder into the molten pool to produce foam slag.
The use effect of the comprehensive tube furnace door gun is to improve the oxygen blowing efficiency and shorten the smelting time by 5-15 minutes; Save 80% to 90% of oxygen blowing pipes, reduce costs by 15-30 yuan per ton of steel; Improved labor conditions for workers, replacing manual oxygen blowing by 90%.
Composition of Pipe Furnace Door Gun Device
The furnace door gun is composed of a water-cooled oxygen gun and a furnace door gun; The mechanical system consists of a large arm rotation, gun body rotation, gun body swing, and lifting system; The oxygen gun equipped on the furnace door gun device can assist in melting during the melting period and decarbonize and refine during the oxidation period. The furnace door gun device is equipped with a carbon gun, which is mainly used to make foam slag.
Consumable tube furnace door carbon oxygen gun
At present, the electric furnace door gun is basically designed with water cooling. Because the water-cooled oxygen lance also has some shortcomings, Baden Iron and Steel Company has researched and applied the consumable furnace door lance, which has the function of injecting lime and carbon powder to produce foam slag. Compared with water-cooled oxygen guns, its advantages are a large operating safety factor, a large blowing angle, and the ability to directly cut scrap steel. The disadvantage is that the cost of blowing oxygen is high, and it cannot be continuously blown.
Types of oxygen combustion assisted melting fuels
The fuel used for the burner includes three types: solid, liquid, and gas. Currently, light diesel fuel is preferred among liquid fuels as it is the preferred auxiliary fuel due to its convenience, cleanliness, and easy equipment maintenance. The main gas fuel for box furnaces is natural gas, which is currently limited in resources and rarely used in China; However, gas and other gaseous fuels are not used due to their low calorific value and large exhaust emissions. China has developed coal oxygen technology for solid fuels based on resource conditions, but the thermal efficiency of injection is low and the investment is large. In addition, the preparation, storage, transportation of powdered coal, as well as the removal and separation of sulfur and ash residues in combustion products, are relatively cumbersome.
The heat of chemical reaction accounts for a significant proportion of the energy input of the electric furnace, reaching 20-30%; Especially for tubular furnaces, when molten iron is used in electric furnaces, the proportion of chemical heat reaches 40-50%, which is a characteristic of modern electric arc furnace steelmaking processes; Oxygen technology is a concentrated manifestation of modern high-tech, and the combination of power supply and oxygen supply is an important step in improving production rhythm and energy conservation and consumption reduction for tubular and box electric furnaces.
The theoretical calorific value generated by the oxidation of 1kg of each element in the molten pool under oxygen blowing conditions
Assuming per kW? The electricity price for h is 1.
EBT oxygen gun
In order to achieve slag free tapping in electric arc furnaces, eccentric bottom tapping (EBT) technology is adopted. This not only reduces the amount of slag in the tapping process, but also shortens the smelting cycle and reduces the tapping temperature drop. But at the same time, it also makes the EBT area one of the cold zones of UHP-EAF, resulting in a slower melting rate of scrap steel in this area and significant differences in the composition of the melt pool compared to the central area. To solve the problem of EBT cold zone, an EBT oxygen gun can be installed above the eccentric furnace side to blow oxygen and assist in melting in this zone. The EBT oxygen gun can promote the melting of scrap steel in this area, and after the appearance of a molten pool, the temperature of the molten pool in the EBT area is increased, the composition of the molten pool is uniform, and CO reburning is achieved.
The use of EBT oxygen gun completely solves the problems of scrap steel in the EBT area not yet melting during tapping and the inability to open the tapping hole. At the same time, the error between the temperature and composition of the EBT area during tapping and the temperature and composition of the furnace entrance area is only 0.5% to 1.0%. The impact force of the EBT oxygen gun needs to be considered in its design. Due to the shallow molten pool in the EBT zone, the penetration depth of the oxygen jet in the EBT oxygen gun should not exceed 2/3 of the molten pool depth in the EBT zone, and the steel mouth area should be avoided. Considering the attenuation of oxygen jet, a telescopic drive EBT oxygen gun is adopted, and the position of the gun is adjusted according to the smelting situation.
Factors affecting the efficiency of the burner
A tube furnace produces heat for steelmaking through the arc striking of the electrode. The steel material slowly melts from the center of the electrode to the surrounding area, resulting in high heat loss and longer melting time. The oxygen burner, also known as the oxygen burner, is arranged on the wall of the cold zone of the electric furnace, and relies on the reasonable matching of the burner and the arc power supply to achieve balanced melting of scrap steel. The efficiency of the burner depends on: (1) the temperature and heating area of the scrap steel. If the scrap steel temperature is high in the early melting stage and the heating area is large, the efficiency of the burner can reach 80%; (2) Determine the appropriate oxygen oil ratio at different stages, and reduce the amount of burner oil when the scrap is close to melting. The fuel used for the burner is not only oil, but also natural gas or coal powder. There are also cases where oxygen burners are used to preheat scrap steel at the flue, but attention should be paid to environmental protection.
Tube furnace bundle jet oxygen gun
CoherentJet oxygen gun technology is a new type of oxygen injection technology that can solve the shortcomings of traditional supersonic oxygen guns such as short injection distance, low impact force, and low oxygen utilization rate. It mainly uses the envelope formed by medium combustion to protect the main oxygen flow. The Mach number at the outlet of the cluster jet oxygen gun can reach around 2.0, and the jet distance in the technical state can reach 1.2-2.1 meters. It can be directly installed on the furnace wall to achieve functions such as melting and decarbonization.
The main benefits of applying a cluster jet oxygen gun to electric furnaces are reflected in:
(1) It has multiple functions such as oxygen blowing, combustion, and secondary combustion, and achieves centralized automatic control, thereby reducing the cost of facilities and processes set up separately for each system.
(2) Due to the setting of the combustion function, scrap steel can be preheated and melted in advance, thereby reducing electrical energy consumption (at least 20kW? H per ton of steel).
(3) Due to its strong impact and stirring capabilities, the utilization rate of oxygen and sprayed carbon powder is improved, thereby reducing the consumption of oxygen and carbon powder.
(4) Due to the setting of the secondary combustion function, the combustion of CO in the furnace is fully utilized to increase furnace temperature, thereby reducing energy consumption.
(5) Due to the reduction of splashing and the reduction of iron content in the slag, the metal yield is increased and the maintenance cost of the furnace body is reduced.
The cluster oxygen gun can cut and melt scrap steel more quickly, effectively blowing oxygen into the molten pool, greatly improving the utilization rate of oxygen.
First, open the secondary oxygen system, delay the opening of the compressed air system for a certain time, and then delay the opening of the fuel (or gas) system for a certain time, while supplying the main oxygen. The fuel and primary oxygen should be turned off first, and then the compressed air and secondary oxygen should be sequentially turned off. Automatic alarm processing to prevent serious safety accidents caused by oil pressure exceeding compressed air pressure.

The above content is organized by Superb heater Company, super heater. Mainly professional production: industrial heating elements, temperature measuring elements, production equipment, accessories, and raw materials such as tubular heaters, tubular heaters, belt heaters, ceramic heaters, silicone rubber heaters, thermocouples, etc.

Welcome global industry partners to discuss cooperation!