1.1 Flue gas cooling system of converter gas dry dust removal equipment
(1) Overview of the flue gas cooling system of converter gas dry dust removal equipment
During the conversion process of the converter, the carbon-oxygen reaction generates a large amount of CO, CO2 gas and traces of other high-temperature gases. It also carries a large amount of iron oxide powder, metallic iron and other fine particles. Brown-red smoke. Because the flue gas has the characteristics of high temperature, large amount of flue gas, high dust content, small dust particles, toxic and flammable explosive properties. If left unattended, it will cause severe air pollution. From the perspective of meeting energy reduction and emission reduction, the unburned method should be adopted for treatment and recovery.
The vaporization cooling and cooling system is used to collect and conduct the flue gas, and at the same time, the flue gas can be cooled and cooled, so that the volume of the flue gas is reduced, and the purification system equipment is easy to handle.
(2) Composition of vaporization cooling system of converter gas dry dust removal equipment
The main function of the converter gasification cooling and cooling system is to collect the flue gas emitted from the furnace mouth to cool down and recover the waste heat at the same time. The system is mainly composed of equipment such as fume hoods and vaporized cooling flues.
(3) Evaporative cooling flue of dry gas dedusting equipment for converter gas
The conveyance of the flue gas is completed by vaporizing and cooling the flue. Its role is to introduce the flue gas into the purification system, cool the flue gas, and recover the waste heat. The high-temperature flue gas has a large volume, such as purification at high temperature, which makes the volume of the purification system equipment very large. In addition, the low dust content per unit volume is not conducive to improving the purification efficiency, so the flue gas should be cooled and cooled by vaporizing the flue before and during purification.
2.1 System Overview
Our company draws on domestic and foreign converter dry dust removal technology, combined with the actual application of converter steel purification technology in domestic iron and steel enterprises, and cooperates with a number of steel design and research institutes to make breakthrough improvements to some of the existing wet dust removal key equipment. , Independently developed a new wet dust removal process-a new Tarvin semi-dry converter gas purification and recovery OG system (referred to as the new Tarvin OG system), which has been applied to nearly 20 converters with a capacity of 500 tons or more. The process flow is smoke After the gas is cooled by the vaporization cooling flue, the temperature is reduced from about 1450 degrees to about 800 degrees, and then passes through the high-temperature non-metal expansion joint into the spray evaporation cooling tower for rough dust removal, and then enters the upward circular seam Venturi tube for fine dust removal. , And then enter the swirling multi-baffle dehydrator for fine dehydration, and then enter the fan through the pipeline to pressurize, recycle or discharge.
2.3 System main equipment
(1) Spray cooling tower (also referred to as "evaporative cooling tower")
(2) Ring slit adjustable venturi (also referred to as "ring slit two")
2.4 System Features
(1) The system has high dust removal efficiency, which can solve the current situation of flue gas overflow from the furnace mouth and poor chimney emission effect;
(2) The system process is simplified and maintenance is simple, which reduces the labor intensity of workers;
(3) The system has a low resistance to operation, which can reduce the huge operation cost of 氐 compared with traditional technology;
(4) The system consumes less water and has lower operating costs;
(5) The system runs stably, the dust removal efficiency is high, and the pollution is reduced.
2.5 System Design Diversification
It can be optimized according to the specific requirements of the user's site to make the system achieve the best dust removal effect.
3.1 System Overview
There are currently three main methods for the purification and recovery of converter gas:-one is the all-wet method, one is the combination of dry and wet methods, and-the other is the all-dry method. At present, the all-wet method is commonly used in China, also known as OG (〇 xygen Converter Gas Recovery) method.
The so-called OG method is to use atomized fine water droplets to capture the tiny smoke and dust in the flue gas, and then condense into larger particles. After passing through a venturi tube series dehydrator, the dust-containing water droplets are separated from the gas, so that the flue gas is separated. After cooling and purification, the purified flue gas is recovered.
Due to the high temperature of the converter flue gas, the large volume of gas, the large dust content, the gas is toxic and explosive, and its release will pollute the environment and other characteristics. Our company has developed a collection of relevant treatment methods based on the different characteristics of the converter flue gas and smoke. Converter gas cooling, dedusting, and recycling functions in one integrated system-OG system.
3.2 System composition of converter gas dry dust removal equipment
The OG system consists of flue gas cooling equipment, flue gas purification equipment, flue gas recovery and release equipment, and automatic control equipment. details as follows:
①OG system flue gas cooling equipment consists of smoke hood and lifting device, vaporized cooling flue and converter oxygen lance lifting system.
② The OG system flue gas purification equipment consists of ―grade Venturi tube (spray tower can also be used), secondary Venturi tube and dehydrator. Among them-Grade Venturi tube: It mainly includes water-cooled jacket, overflow trough, one-piece contraction section, one-piece throat section (divided into adjustable and sizing type), and one-piece diffusion section. Two-stage Venturi tube: It mainly includes Erwen contraction section, Erwen throat section (divided into nitrogen barrel needle type, nozzle splash type) and Erwen diffusion section.
③ OG system smoke recovery and release equipment consists of pneumatic three-way switching valve, pneumatic bypass valve, pneumatic water seal check valve, pneumatic blind plate valve, fan, hydraulic coupling and ignition release device.
④ OG system automatic control equipment mainly includes: furnace mouth differential pressure control, RSW opening degree follow-up control ,: steam drum feed water impulse control and automatic flushing; purge control and movable hood automatic lifting and fan speed control and other equipment.
5Gas dry method (LT method) purification and recovery system
Oxygen converter steelmaking uses oxygen blowing smelting, which will generate a large amount of soot and CO gas. The soot composition of metallic iron accounts for 13%, FeO accounts for 68.4%, and Fe2O3 accounts for 6.8%. When the CO content is about 60%, its calorific value can Up to 8000KJ / Nm, and the amount of smoke is generally 10 ~ 20kg / t steel. It can be seen that in the oxygen converter steelmaking, the CO content in the converter gas is very high, and the iron content in the flue dust is also very high. Therefore, it has a high value for recycling. "Purification and Recycling Technology" is a national key development and promotion technology project.