Through statistics, analysis and summary of common faults in the blast furnace ironmaking production process, we find out their influencing factors and formulate corresponding countermeasures to deal with equipment faults in a timely manner, thereby reducing the equipment failure rate and improving production. efficiency to achieve safe and efficient production of blast furnace ironmaking.
Keywords: blast furnace; ironmaking; production; failure analysis; countermeasure research
Our country is the first country in the world to carry out iron smelting. After hundreds of years of development, 95% of the countries in the world are now able to achieve blast furnace iron smelting. However, in the process of blast furnace production, various production equipment failures often occur, sometimes causing serious accidents. Therefore, it is very important to pay attention to the production equipment failures of blast furnace ironmaking, so we analyze the corresponding causes and formulate measures to Reduce the occurrence of failures, ensure smooth operation of blast furnace equipment, and improve production efficiency.
Failure analysis and countermeasures of blast furnace ironmaking feeding equipment
The feeding equipment of the blast furnace mainly includes feeding equipment, belt conveyors, feeders, vibrating screens, weighing trucks, coke bins, and ore storage tanks. An indispensable part of the blast furnace equipment production process is the feeding equipment, which can prepare various ores and coke into certain batches according to a certain quality, and then feed the blast furnace’s loading machine in accordance with the prescribed discharge sequence. During the blast furnace production process, various raw materials and coke are lifted from the ground to the top of the furnace with the help of loading equipment to wait for production and processing.
The main function of the blast furnace top charging equipment is to receive the raw materials and coke transported to the top of the furnace by the loading machine, and then load various materials into the furnace throat according to the requirements, so that the furnace materials can be more reasonably distributed and the The entire blast furnace is sealed. At present, most blast furnace manufacturers use bellless furnace tops, which have good production efficiency.
Failure analysis of feeding equipment
There are currently two most commonly used feeding control systems: the feeder feeding control system and the belt conveyor feeding control system.
Car loading control system
The main fault point of the loading control system of the feeder is the material winch. The main faults are as follows:
1) Damage to major components, such as large gears, bearings, shafts and other major components.
2) The reducer is overheated and causes jitter.
3) Noise and leakage occur.
Belt conveyor feeding control system
The belt machine feeding control system often fails:
1) The surface of the tape is seriously damaged or scratched.
2) Belt deviation.
3) The roller cylinder is severely damaged.
4) The temperature of the roller bearing rises and there is loud noise.
5) The roller is stuck.
6) The roller body is severely damaged.
Countermeasures for feeding equipment failure
For the feeding device system, winch and other mechanical equipment failure points that are prone to occur, we must pay attention to the following management tasks.
1) Carry out inspection and management of mechanical equipment. Find out the time period changes of each mechanical equipment failure point.
2) When performing inspection, confirm whether the sound is different from usual.
3) Check whether the screws are loose or offset.
4) Feel the vibration with your hands for any abnormality to determine and check whether maintenance is needed.
5) For the failure of the feeding system of the belt conveyor, it can be solved by maintenance, cleaning surface impurities, or refueling and replacing rolling bearing rollers.
Failure analysis and countermeasures of blast furnace top charging equipment for ironmaking
Overview and fault analysis of blast furnace ironmaking top charging equipment
The furnace top charging equipment consists of a material tank, a distributor, a swing chute, an airtight box, etc. Its main equipment, the distributor, is responsible for producing uniform cloth in the circumferential direction. Common faults are as follows:
1) The output voltage of the distributor is high during operation.
2) The distributor will make abnormal noise when it is running.
3) The support roller of the distributor is stuck.
4) The distributor vibrates greatly.
5) The noise of the distributor generator is abnormal.
6) The bearing noise of the distributor bevel gearbox is abnormal.
Countermeasures for faults in blast furnace top charging equipment
The blast furnace top charging control system generally uses a bellless top method to charge the blast furnace. The bellless furnace top charging control system uses distributors, swing chutes, air-tight boxes, probes and other equipment. If high-pressure operations are carried out, pressure equalization and pressure relief equipment must be installed, and the sealing between each equipment must be done. Poor sealing will not only expose parts of the equipment to gas impact, reduce the service life, but also cause the bell to fall into the furnace. ACCIDENT. The opening and closing of bellless furnace tops shall comply with safety procedures. Therefore, corresponding interlocks should be set up between relevant devices to avoid man-made failures.
Hydraulic system equipment failure analysis and countermeasures
As the most important power system component in the blast furnace, the hydraulic system can provide the power required for production and processing for the mud gun and material bell on the top of the blast furnace.
Common faults of hydraulic system equipment
1) The system oil temperature is abnormal. The oil temperature is too high or the oil temperature is too low.
2) The oil level is abnormal. The oil level is high or low, or the oil level fluctuates greatly.
3) The system oil pressure is abnormal.
4) The system operation department is dynamically unstable.
Countermeasures for hydraulic system equipment failure
In order to ensure the stable performance of the hydraulic control system, the equipment must be used, maintained and maintained appropriately; in order to reduce the impact of the harsh working environment, a strict maintenance system must be established. In response to the above failure factors, consumables and accessories, such as hydraulic system oil, filters, air filters, etc., must be inspected daily; tank water pumps, hydraulic system motors, valves, etc. must be inspected weekly; hydraulic Cylinders, oil coolers, accumulators, etc. are inspected monthly; connecting pipes, rubber hoses, plastic pipes, etc. are inspected annually; electrical automation equipment such as detection components and electronic equipment are inspected monthly. If there are any abnormalities, handle them in time to ensure that the equipment is in good operating condition.
Failure analysis and countermeasures of mechanical equipment in the casthouse
Failure analysis of mechanical equipment in the casthouse
The mechanical equipment of the blast furnace tapyard includes tap opening machines, mud cannons, and swing chutes. Tap opening machine, this equipment can open the blast furnace tap hole and promote the smooth flow of molten iron. The mud gun can quickly drive refractory gun mud into the tap hole after the blast furnace completes tapping, so that the tap hole can be perfectly sealed. The function of the swing chute is to make the molten iron swing to flow into the empty tank after a molten iron tank is filled when iron is tapped in front of the furnace.
1) Failure of the tap opening machine. The most common tap opening machines are drilling type and punch drilling type. Drilling failure occurs when the curved rail vehicle reaches a certain section and then gets stuck on the rail, causing difficulty in driving. Drilling failure occurs when the drill rod on the tap opening machine does not rotate, or the vibration meter does not work.
2) Failure of hydraulic mud cannon. The cylinder does not move or the rotational speed changes too late; the dynamics are too late when pumping mud; the mud cylinder is severely sanded; the mud nozzle does not match the iron mouth.
3) Failure of the swing chute. The hydraulic cylinder does not move; the solenoid control valve fails; the chute cannot swing normally.
Countermeasures against mechanical equipment failures in the casthouse
The working environment of the mechanical equipment in the tapyard in front of the furnace is harsh and is mainly affected by high temperatures. It is easy to scorch and damage the hydraulic system cylinders, valves, connecting hoses, etc. In order to ensure the operating performance of the equipment, the vulnerable parts of the equipment in front of the furnace should be checked in time before tapping and after blocking. If problems are found, they should be replaced in time to avoid malfunctions during use and causing major accidents. Secondly, regular equipment inspections and regular equipment maintenance and repair systems must be formulated to ensure the operating performance of the equipment.
Boiler structure and tuyere failure analysis and countermeasures
The air outlet often fails
The road conditions of the blast furnace are not smooth and the air flow in the furnace is unstable, which may easily cause tuyere failure, such as the tuyere burning red, air leakage or burning through; the air intake of the tuyere is small, or the tuyere is completely inactive; the spherical surface of each interface has air leakage; the direct air supply blow pipe burns red ; The air outlet and the small sleeve are burned out, leaking, blasting, and collapse.
Countermeasures for tuyere failure
The blast furnace is of high temperature and high pressure, and no water supply or power outage can occur during the operation. Especially in large and medium-sized blast furnaces, safe and reliable technical measures should be adopted to ensure safe power supply and water supply.
Since the high-heat furnace body, tuyere, furnace bottom, shell, water slag, etc. all need continuous water supply, if it is interrupted, the cooling water device will be damaged, and even a major accident may cause production shutdown. Therefore, for safe power supply, the following safety measures should be adopted in large and medium-sized blast furnaces:
1) Equip the tap water system with a corresponding number of spare water pumps; each pump station building should be equipped with a second power supply; a water tower for water supply should be provided to ensure timely power supply after the diesel water pump is turned on; and a return water tank should be provided to ensure that the diesel water pump is powered on. Ensure water circulation supply when there is no external supply; install continuous filters on boiler and tuyere water supply pipes; use pipes during supply and exhaust to prevent water bursting.
2) Power supply safety technology. When an unexpected power outage occurs, personal safety and facility safety must be considered, and necessary security personnel must be installed to respond to safety measures.
3) Equipped with a dedicated and self-prepared diesel engine power generation unit. All computers, instrument power supplies, emergency power supply equipment and communication signals are under the unified responsibility of security personnel. Each electrical room and operating hours should be equipped with chromium battery fluorescent lamps for emergency lighting. The blast furnace section should also conduct regular drills for relevant staff on emergencies such as power outages, circuit breaks, air cessation, and furnace burn-through to enhance the staff’s ability to respond to incidents.
Hot blast furnace and dust removal equipment faults and countermeasures
Failure analysis of hot blast furnace and dust removal equipment
The working principle of this equipment is to first use combustion air or gas to ensure full combustion in the combustion chamber. Finally, the high-temperature flue gas generated can smoothly enter the regenerator to heat the checker bricks, and then the combustion will stop. At this time, the cold air sent by the air cooler passes through the regenerator, taking away the heat in the checker bricks. During this process, the cold air takes away the heat and its own temperature also rises, and is sent into the blast furnace through the hot air surround.
In the process of blast furnace production, there is usually a large amount of waste gas, which mainly includes dust with a calorific value of 3300~4200 kJ/m3 and CO with a φ (CO) of 20%~30%. This waste gas can take away 1/3 of the heat in the blast furnace from various fuels such as coke. The main function of dust removal equipment is to remove dust from raw gas. Through dust removal, the dust content in raw coal gas is greatly reduced, and it can become industrial gas for coking plants, power plants, rolling mills and ironmaking plants [7-10]. In addition, the slurry after dust removal can be used as raw material and returned to the sintering plant, or it can be used directly as blast furnace charge.
The maintenance period of hot blast stoves is generally designed to be more than 20 years. Frequent equipment failures and countermeasures are mainly to frequently check whether the fan and parts are damaged, whether the flange joints are leaking, and the various valves connected to them, such as hot blast valves and Check whether the cold air valve, combustion valve, gas valve, etc. are damaged, and ensure the good operation of the equipment through inspection. Among various dust collectors, bag dust collectors have the highest dust removal efficiency.
The main faults of the bag dust collector are: the dust removal resistance is too high; the dust removal resistance is too low; the exhaust gas content exceeds the abnormal limit; the pulsation valve is always open; the pulsation valve is always closed; the pulsation valve is weak or fails to open normally during injection; the electrical control valve does not operate Or air leakage.
Countermeasures for faults in hot blast stoves and dust removal equipment
Blast furnace ironmaking is a continuous production, so any unplanned wind break is a liability accident. Therefore, first of all, regular inspections of electrical equipment should be done, especially to check whether the various valve motors can be opened smoothly, whether the motors are overheated, whether the output axis and operating steering are reversed, and whether the valve stems and rolling bearings are worn. , Whether the valve plate operates flexibly, etc. In addition, regular maintenance and planned inspections should be carried out to eliminate potential faults in a timely manner to minimize the wind break time, so as to ensure the smooth operation of the blast furnace.
Conclusion
By analyzing and studying blast furnace ironmaking production failures, formulating corresponding countermeasures to reduce equipment failure rates and improve production efficiency play a very important role in blast furnace ironmaking production. To reduce the equipment failure rate, extend the long-term stable operation life cycle of the blast furnace, and ensure the safety of the blast furnace, we must strengthen scientific management, pay close attention to equipment failure management, analyze failure factors, and take corresponding measures to solve equipment failure problems and achieve improvement. The purpose of equipment operation efficiency and quality.