GB 16543-1996 Safety regulations for explosion prevention of bituminous coal injection system in blast furnace
Some standard content:
3165431996
Blast furnace bituminous coal injection is one of the important technical measures for modern blast furnace ironmaking. However, bituminous coal is explosive, and spontaneous combustion, fire and explosion accidents have occurred in blast furnace bituminous coal injection systems at home and abroad. This standard is formulated to ensure the safe production of blast furnaces. This standard absorbs the reasonable contents of relevant foreign standards and regulations. Ironmaking plants can formulate implementation details based on this standard and the actual situation of their own plants.
This standard is proposed and managed by the Ministry of Labor.
The responsible drafting unit of this standard: Safety and Environmental Protection Research Institute of the Ministry of Metallurgical Industry. Participating drafting units of this standard: Beijing Iron and Steel Design and Research Institute of the Ministry of Metallurgical Industry, Ma'anshan Iron and Steel Design and Research Institute of the Ministry of Metallurgical Industry, Anshan Iron and Steel Company, Wuhan Iron and Steel Company.
The main drafters of this standard: Xu Tianrui, Wang Jun, Tang Wenquan, Ren Zhenhua, Tang Qinghua, Kang Wenjin, Zhang Zhongqi, Fan Xisheng, Zhou Hao. 662
1 Scope
National Standard of the People's Republic of China
Safety regulations for the explosion precautionsof bituminous coal injection into blast furnaceGB 16543—1996
This standard specifies the basic requirements for the prevention and protection of coal powder explosion in the bituminous coal injection system of the blast furnace of the ironmaking plant. This standard is applicable to the design, construction and acceptance, as well as the operation, maintenance, overhaul and management of the new construction, expansion and renovation projects of the bituminous coal injection system and the mixed bituminous coal and anthracite injection system of the blast furnace of the ironmaking plant. The anthracite injection system can be implemented by reference. 2 Referenced standards
The provisions contained in the following standards become the provisions of this standard through reference. When this standard is published, the versions shown are valid. All standards are subject to revision, and the parties using this standard should explore the possibility of using the latest version of the following standards. GB15577—1995 Safety regulations for dust explosion prevention GB/T15604--1995 Terminology for dust explosion prevention
GB/T15605—1995 Guidelines for pressure relief of dust explosion GBJ16—87 Code for fire protection of building design
GB50058-92 Code for design of power plants for fire and explosion hazardous environments Regulations for safety and technical supervision of pressure vessels of the Ministry of Labor 3 Definitions
This standard adopts the following definitions.
3.1 Pulverized bituminous coal Pulverized bituminous coal is a collection of coal particles with a dry ash-free volatile matter content of more than 10% that can be suspended in the air flow (referred to as pulverized coal). 3.2 The system of bituminous coal injection into blast furnace is a system from the raw coal and drying medium entering the coal mill in the raw coal bunker to the pulverized coal and the carrier medium being injected into the blast furnace. 3.3 The system of pulverized coal preparation The system of drying and grinding raw coal into pulverized coal and collecting and storing it from the raw coal bunker, heating furnace and its gas supply system to the pulverized coal bunker (referred to as the pulverizing system).
3. 4 The system of pulverized coal conveying The system of pulverized coal conveying The system of starting from the bunker pump after the pulverized coal bunker of the pulverizing system to the bag collector before the injection system (referred to as the pulverizing system). 3.5 The system of pulverized coal injection The system of injecting pulverized coal into the blast furnace with the carrier medium from the pulverized coal bunker of the injection system to the injection gun (referred to as the injection system). 3.6 Drying medium Dryer
The gas used for both drying and carrying pulverized coal in the pulverizing system. 3.7 Carrier
Approved by the State Administration of Technical Supervision on September 25, 1996, and implemented on March 1, 1997
GB16543--1996
Gas used to carry pulverized coal in pulverizing and injection systems. 3.8 Pulverized coal collection tank A container used to temporarily store pulverized coal at normal pressure. 3.9 Pulverized coal storing tank A pressure vessel used to receive a fixed amount of pulverized coal from a pulverized coal collection tank at normal pressure and place it into an injection tank under pressurized conditions in an injection system.
3.10 Coal injection tank A pressure vessel used for pulverized coal injection with a working pressure higher than normal pressure. 3.11 Mixer
A device used to mix gas and pulverized coal.
3.12 Fluidizer
A device used to fluidize pulverized coal in a container.
3.13 Injection using single pipe The outlet of the injection tank is equipped with only one (or two) injection pipes, and the end of the injection pipe is equipped with a multi-head distributor. 3.14 The safe position of value The opening of each valve is placed in a position that can prevent the system from heating up, pressurizing, increasing oxygen, accumulating powder, and backflow of hot air. 4 General provisions
4.1 The first person in charge of the design, construction and production of the blast furnace coal injection system should be familiar with the functional requirements and fire and explosion hazards of the system. 4.2 The blast furnace coal injection system should have the following functions: a) The scale and layout should meet the requirements of the blast furnace or blast furnace group it serves. b) It can process raw coal into pulverized coal, and can continuously transport pulverized coal to the pulverized coal bin, injection tank, and blast furnace under dilute or dense phase conditions according to the designed flow rate.
c) It can operate normally for a long time and reduce unexpected emergency shutdowns to a minimum. d) Equipped with monitoring means, control equipment and devices that meet safety requirements to ensure that the system can operate normally and can be safely started or stopped repeatedly.
4.3 During the design and production process, measures should be taken to control the following dangerous factors: a) Spontaneous combustion of raw coal in the raw coal bunker, and the input of burned raw coal to the coal mill. b) Poor or interrupted feeding of raw coal leads to a sudden rise in temperature in the system. Spontaneous combustion of coal powder in the system:
Dead corners exist in the coal powder container and pipeline;
The coal mill with load trips;
The air supply temperature of the heating furnace is too high;
Air leaks into the equipment or pipeline filled with inert gas, and hot air or combustible gas flows back into the raw coal bunker. d) Some raw coal releases combustible gas when it is ground, forming a more explosive mixture in the equipment and pipeline. The free radicals formed by some combustible gases can promote the spontaneous combustion of coal powder.
e) The type of coal used for production is significantly different from the type of coal designed. Fire in the pulverized coal handling system may cause explosion or explosion may induce fire. f) Personnel entering the pipeline and equipment with inert gas may cause accidents. Personnel are not trained or the training is not up to standard, which leads to poor maintenance or improper operation of equipment. h) The explosion force in air-pressurized pulverized coal equipment is stronger and the period of spontaneous combustion is shorter. j) The oxygen-coal gun supply system does not have a reliable safety interlock. 664
GB16543-1996
k) There are oil stains and impurities in the oxygen pipe network and oxygen-coal gun for oxygen-coal injection. 1) The injection oxygen pressure is lower than the hot air pressure of the blast furnace. m) Static charge accumulation produces discharge sparks.
4.4 The person in charge of the design of the blast furnace coal injection system shall be technically responsible for the system's functions, fire and explosion prevention measures and their configuration. 4.5 The person in charge of the construction of the blast furnace coal injection system shall organize the construction according to the design and be responsible for the consequences of construction changes made without the consent of the design unit.
4.6 The director of the iron and steel plant shall be responsible for the training of operators in fire prevention and explosion prevention technology and the establishment and improvement of the fire prevention and explosion prevention responsibility system. 4.7 The design of the blast furnace coal injection system shall be approved by the relevant departments, and the approver shall be responsible for the approval of the fire prevention and explosion safety of the system. 4.8 The design unit shall obtain the blast furnace bituminous coal injection system design license issued by the Ministry of Metallurgy before engaging in design work. 4.9 The three parties involved in the design, construction and production operation of the blast furnace coal injection system shall comply with this regulation to coordinate on fire prevention and explosion prevention. 4.10 All operators of the blast furnace coal injection system shall implement the production operation and fire prevention and explosion prevention training, assessment, certification, certification and annual review system for fault records.
5 Design
5.1 General provisions
5.1.1 The powder making system should adopt a full negative pressure powder pressing process with only a typhoon fan and a first-level bag powder collector. The injection system should adopt a single-pipeline injection process. It is advisable to adopt a system that directly connects pulverizing and injection, and it is not advisable to set up a pulverizing system in between. 5.1.2 It is advisable to use a medium-speed coal mill with low air leakage rate, a coal feeder with good air tightness, and efficient pulverizing equipment and accessories. 5.1.3 The inner walls of the coal pulverizer silo, silo pump, coal storage tank, injection tank, etc., as well as the hopper wall of the powder collecting equipment, the powder dropping pipeline, etc. should be smooth, and the angle between the discharge cone wall and the horizontal plane should not be less than 70° or a gas fluidizer should be used. 5.1.4 The design, manufacture and installation of pressure vessels such as silo pumps, coal storage tanks, injection tanks, and air distributors should comply with the "Regulations on Safety Technical Supervision of Pressure Vessels" promulgated by the Ministry of Labor.
5.1.5 Antistatic filter bags should be used for bag powder collectors. 5.1.6 Electromagnetic iron removers should be installed in front of the raw coal silo. 5.1.7 Various compressed gases supplied to the blast furnace coal injection system should be de-oiled and dehydrated. 5.1.8 For non-open type plants without reliable mechanical ventilation, the electrical safety design shall be carried out according to the 10 zones specified in GB50058; in any of the following cases, the electrical safety design may be carried out according to the 11 zones: one plant is an open type building;bZxz.net
one plant is a semi-open type building with sufficient natural ventilation; one plant is equipped with reliable mechanical ventilation. 5.1.9 The power supply of the system shall be designed as two independent power supplies. 5.1.10 All equipment, containers and pipelines shall be provided with anti-static grounding, and the flanges shall be connected with wire jumpers, and anti-static design verification shall be carried out. 5.1.11 It is advisable to install a mobile or fixed vacuum cleaner unit, and it is strictly forbidden to use compressed air to clean the surface of the plant and equipment. 5.2 Plant
5.2.1 It shall be designed according to the Class B fire hazard building specified in GBJ16. 5.2.2 A fire water pipeline system shall be provided, a fire truck passage shall be provided around the plant, and alarm facilities directly connected to the fire station shall be provided in the main fire hazard places.
5.2.3 The floor and inner wall should be flat and smooth (painted or tiled, etc.), and flushing and drainage facilities should be provided. Sewage must be purified before it can be discharged. Areas where powder may accumulate should be avoided as much as possible. Areas that are difficult to avoid should be easy to clean. 5.3 Pipelines
5.3.1 The number of flange connections in the pulverized coal pipeline should be reduced, and the inner wall should be smooth. 5.3.2 The layout of the pulverizing pipeline should avoid dead corners where pulverized coal accumulates, and the angle with the horizontal plane should not be less than 45°. When horizontal pipelines must be arranged, the design flow rate under rated load conditions should not be less than 25m/s. 665
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5.3.3 The design flow rate under minimum load conditions in the pulverized coal pipeline after the pulverizer outlet should not be less than 15m/s. 5.3.4 The flow rate in the coal transportation and coal injection pipelines should not be less than 1.25 times the sedimentation velocity. 5.4 Inerting
5.4.1 The pulverizing system shall use inerting gas as the drying medium. The designed oxygen content at the end of the negative pressure system shall not be greater than 12%. 5.4.2 When compressed air is used as the carrier medium for powder conveying and injection, it shall be able to be immediately converted to nitrogen in an emergency. 5.4.3 The pulverized coal bunker of the pulverizing system shall be equipped with a nitrogen fluidization device and a nitrogen filling device. 5.4.4 The pressurization and fluidization medium of the bunker pump, coal storage tank, injection tank and other pressure vessels in the pulverizing and injection system must be nitrogen or other inerting gases.
5.4.5 Bunker pumps, coal storage tanks, injection tanks, pulverized coal bunkers and other equipment or devices shall be equipped with flexible joints for emergency connection to compressed air pipelines and valves, and can be interchanged with nitrogen pipelines.
5.4.6 The bag powder collector and the pulverized coal bunker of the injection system shall be equipped with a nitrogen filling device. 5.4.7 The nitrogen tank shall be installed outdoors.
5.5 Explosion venting
5.5.1 Except for pressure vessels, all coal powder containers, pipe ends connected to containers and pipe bends should be equipped with explosion venting holes of sufficient area, and their direction should not endanger personnel and other equipment. When it is necessary to set an explosion venting conduit, its length should not be greater than 3m, and it should not have elbows.
5.5.2 The explosion venting of containers, equipment, pipelines and workshops should be designed in accordance with GB/T15605. 5.6 Explosion isolation, structural explosion suppression and fire extinguishing
5.6.1 The spray tank and spray pipeline must be able to be automatically cut off in an emergency. 5.6.2 The air supply (compressed air or nitrogen) pipelines of the powder conveying and spraying systems should be equipped with check valves. 5.6.3 The design and configuration of process equipment and pipelines should minimize the number of containers, reduce the diameter of the pipeline, reduce the length of the pipeline, reduce the number of elbows, eliminate local powder accumulation, and increase the concentration and speed of coal powder in the system, while ensuring production needs. 5.6.4 The pulverizing system shall be equipped with an emergency nitrogen filling system. 5.6.5 A water mist fire extinguishing system or steam fire extinguishing system shall be installed in the plant building, and the use of water jet fire extinguishing methods is prohibited. Carbon dioxide or phosphate fire extinguishing devices or systems shall be installed in the pulverized coal container. 5.6.6 All electrical rooms shall be equipped with fire extinguishing devices or fire extinguishing systems. 5.7 Monitoring alarm and safety interlock
5.7.1 Upper limit temperature monitoring devices shall be installed at the inlet of the coal mill, the inlet and inside of the bag collector, the pulverized coal bin, the bin pump, the coal storage tank, the injection tank, etc. Key locations such as the pulverizer outlet shall be equipped with upper and lower limit dual temperature monitoring devices. 5.7.2 High and low material level monitoring devices shall be installed in the raw coal bin and the pulverized coal bin, and alarms shall be sounded when the limit value is reached. 5.7.3 The pulverizing system shall be equipped with online monitoring devices for oxygen content and carbon monoxide concentration, which shall alarm and automatically fill nitrogen when the upper limit value is reached. 5.7.4 The difference between the pressure of the injection tank, the outlet pressure of the mixer and the hot air pressure of the blast furnace shall be subject to safety interlock control. 5.7.5
The difference between the pressure of the injection gas and the pressure of the injection tank shall be subject to safety interlock control. 5.7.6 The oxygen supply system of the oxygen-coal gun shall have the function of automatic switching or nitrogen filling protection. The main oxygen supply pipe in front of the furnace shall be equipped with a protection function. 5.7.72
5.7.8 All pneumatic valves of the pulverized coal conveying system and the injection system shall be able to switch to a safe position in the event of an accidental power failure. 6 Construction and trial operation
6.1 Construction
6.1.1 The construction unit shall formulate construction explosion-proof safety regulations based on the design and site conditions. 6.1.2 When the construction site is close to the equipment of the coal-injection system that has been put into production, temporary fire and explosion separation and sufficient fire-fighting equipment shall be set up, and the construction personnel shall have a construction work permit and a fire permit. When it comes to equipment in use, the equipment should be stopped before construction according to the provisions of 7.4.1, 8.6 and 8.7. 6.2 Commissioning
GB16543--1996
6.2.1 The construction, construction and design units should form a commissioning leadership group (or command center) to be responsible for formulating acceptance standards and commissioning explosion-proof safety regulations, checking the performance of production equipment and explosion-proof facilities and leading the commissioning work. 6.2.2 The commissioning should be carried out in sequence, including single-machine commissioning, no-load linkage commissioning and load linkage commissioning. The latter level of commissioning should be carried out after the previous level of commissioning is qualified. Anthracite should be used during the commissioning. 6.2.3 During the load linkage commissioning, the system interlocking and alarm facilities should be sensitive, the explosion relief and explosion suppression facilities should be reliable, the explosion-proof lamps, communication equipment, and fire-fighting equipment should be complete and intact, and there should be emergency facilities. 7 Operation
7.1 The system should meet the following conditions before operation: a) The system's interlocking and alarm facilities are sensitive. b) The blocking, explosion-proof, explosion-suppression and explosion-relief facilities are reliable. Fire-fighting equipment is intact and effective.
d) Blue measuring instruments are intact and accurate.
e) There are no fire sources and flammable materials on site, in equipment and pipelines, and there is no obstruction in rotating parts and transmission parts. f) Anthracite is available in the raw coal bunker.
7.2 Startup
7.2.1 The pulverizing system should be started in reverse order in the following order: bag powder collector ash cleaning device; powder exhaust fan after the powder collector, coal mill. 7.2.2 The outlet temperature of the coal mill should not exceed 70℃. Anthracite is first added, and bituminous coal is added after the pulverizing system is running normally. The oxygen content of the exhaust gas discharged by the system should not exceed 12% during normal startup, and should not exceed 8% when restarting after abnormal shutdown. 7.2.3 The powder conveying pipe should be purged clean before powder can be conveyed. 7.2.4 The coal injection gun should not be inserted into the blast furnace without purging the injection pipe. When inserting the oxygen-coal spray gun, oxygen should be replaced with nitrogen or other inert gas first, and then oxygen should be used after the spraying is normal.
7.3 Operation
7.3.1 The pressure, temperature, carbon monoxide concentration and atmospheric oxygen content of each monitoring point should be adjusted and controlled to prevent a sharp increase and exceeding the specified value. 7.3.2 When the temperature of coal powder rises sharply and exceeds 85C, nitrogen should be used for powder transportation and spraying. 7.3.3 Air leakage, powder leakage and powder accumulation inside pipelines and equipment should be prevented. 7.3.4 The particle size and moisture of coal powder should be measured regularly. When the coal type changes, the volatile matter of coal powder should be analyzed, the ignition temperature of coal powder and the return flame length should be measured.
7.4 Stopping
7.4.1 Normal Stopping
Anthracite should be used for production 2 hours before the coal mill is stopped. The coal powder in the pressure vessels such as silo pumps and coal storage tanks should be emptied and the pressure should be reduced to normal pressure. If the shutdown exceeds 8 hours, the pulverized coal bin and the pulverized coal injection bin should be emptied. If the shutdown exceeds 8 days, the bituminous coal in the raw coal bin should be emptied. Use the inert gas to protect the injection tank and maintain the tank pressure 0.05~0.10MPa. If the machine is parked for more than 2 hours, the coal powder in the spray tank should be emptied.
--When using an oxygen-coal spray gun, the oxygen should be replaced with nitrogen or other inert gas before the gun is removed. The powder conveying pipe and the spray pipe should be purged clean.
--It is advisable to use inert gas to purge the coal powder in the cyclone powder collector, bag powder collector and other equipment and the pulverizing pipeline. --The opening of each valve should be placed in the parking position. 7.4.2 Abnormal parking
--All monitoring instruments and meters should maintain normal operation, and abnormal values should be handled immediately. ---It is advisable to use nitrogen to purge the accumulated powder in various places inside the pulverizing system. Nitrogen should be used as the carrier medium instead. The fire sources in each equipment and pipeline should be checked and removed.
GB16543-1996
--The outlet temperature of the coal mill should not exceed 70℃, and the oxygen content of the exhaust gas discharged by the pulverizing system should not exceed 8%. The oxygen content in the pulverized coal silo, pulverized coal injection silo, silo pumps and coal storage tanks under normal pressure should not exceed 12%. The oxygen content in the injection tank and silo pumps and coal storage tanks under pressurized conditions should not exceed 8%.
The opening of each valve should be placed in a safe position.
7.5 Emergency operation
7.5.1 When the coal mill is out of coal, the temperature of the drying medium should be adjusted so that the outlet temperature does not exceed 85℃, the oxygen content of the exhaust gas discharged by the system does not exceed 8%, and the operation continues. When the outlet temperature exceeds 85C, operate according to 7.4.1. 7.5.2 When the coal mill is full of coal, stop feeding coal, reduce the supply of drying medium, and continue to operate. If the treatment is ineffective, stop the coal mill and purge the residual powder in the coal mill with nitrogen.
7.5.3 In the event of a sudden power outage, the power supply should be cut off and the opening of each valve should be placed in a safe position. 7.5.4 When the bag collector catches fire, the machine should be stopped immediately, the pulverized coal channel leading to the pulverized coal bin should be blocked, nitrogen should be introduced or a fire extinguisher should be used to extinguish the fire. Water jets should not be used to extinguish the fire.
7.5.5 When pulverized coal in the bin pump catches fire, nitrogen or steam should be introduced to extinguish the fire. If the area of the fire is very small, nitrogen can be used as a carrier gas to transport the pulverized coal.
7.5.6 When the explosion-proof membrane is broken, the explosion-proof membrane should be replaced in time. 8 Maintenance and repair
8.1 The surface of the equipment and the workshop should be kept free of accumulated powder and flammable materials. Clear the bin and tank regularly. 8.2 Key monitoring instruments such as oxygen concentration and carbon monoxide concentration should be regularly calibrated according to the requirements of the instrument product manual. 8.3 Pressure and temperature instruments of the powder making and injection systems should be regularly calibrated. 8.4 Incomplete parts and components such as explosion venting and explosion suppression should be handled in time. 8.5 Pressure vessels should be inspected in accordance with the "Regulations on Safety Technical Supervision of Pressure Vessels" issued by the Ministry of Labor. 8.6 Inspection and maintenance should be carried out with the cooperation of the operators. Fire should be carried out with a fire permit and sufficient fire extinguishing equipment. Fire hazards should be removed after the fire is completed.
8.7 Personnel entering the container for inspection and maintenance should be approved by the supervisor, and there should be special personnel outside the container to monitor and take emergency measures. Before entering the container, the residual powder should be removed, the inert gas and high-temperature gas inlets should be cut off, ventilation should be carried out to reduce the temperature inside the container to below 40°C, and the oxygen concentration and carbon monoxide concentration should be measured to confirm that there is no suffocation, poisoning or other dangers.
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