A Preliminary Exploration of Safety Technology Management Approaches for Flammable and Explosive Tank Areas

Thread Content

As the petrochemical industry moves toward internationalization and intensification, to meet normal production demands, the total capacity of tank groups in flammable and explosive storage areas, as well as the capacity of individual tanks, is increasing. The materials stored there are diverse and include those that are flammable, explosive, toxic, and harmful; in the event of a fire or explosion, this can lead to catastrophic consequences. In response to this, we conducted a preliminary exploration of the safety and technical management for the raw material storage area. I. Regulatory, standard, and institutional requirements: During the daily operations, maintenance, as well as expansion and renovation of the raw material storage areas, it is necessary to strictly comply with the relevant safety specifications, standards, regulations, and requirements set by **, the group company, the company itself, and the product department. These include: 1. **Regulations**: “Code for Fire Protection Design of Petrochemical Enterprises” (GB50160-92), “Regulations on Static Electricity Safety for Liquid Petroleum Products” (GB13348-92) ； 2. The Petrochemical Group Company has issued the following regulations: «Provisions on the Safety Technology Management of Tank Areas in Petrochemical Enterprises (Trial)», «Interim Provisions on the Safety Technology Management of Liquefied Petroleum Gas Tank Areas», «Provisions on Safety Management during Production and Construction», and «Provisions on Safety Management of Key Equipment and Critical Areas» ； 3. Safety regulations for ten key direct operational tasks in the petrochemical industry, such as hot work and working inside equipment ； 4. Safety specification requirements for petrochemical storage and transportation systems. II. Safety Technical Standards 1. Layout 1) In areas with flammable and explosive tanks, it is necessary to ensure that fire dikes and accident containment basins are airtight, sturdy, and reliable, with volumes that meet the specified requirements ； 2) If the spacing between tanks in the tank farm is insufficient, there are not enough tanks in relation to the process equipment, or different types of flammable liquids are stored within the same tank group, etc., and such conditions violate ** as well as the group company’s current safety regulations, standards, and requirements, remedial actions must be taken. 2. Fire dike: 1) The brick-built fire dike shall have its inner surface and top covered with concrete, and it must be able to withstand hydrostatic pressure without leaking ； 2) The areas where pipelines pass through the embankment should be tightly sealed using non-combustible materials ； 3) The outlet for draining water accumulated inside the fire dike should be located outside the dike, and it should be equipped with an easily operable non-standard stop valve; its open or closed state must be clearly visible from a distance ； 4) The water seal well in the tank area cannot replace the drainage switch valve. 3. Fire protection facilities 1) The semi-fixed foam pipeline connections in the tank area should be led outside the fire dike, and ensured to be in good working condition ； 2) The spraying facilities for storage tanks containing flammable liquid materials must be operational during hot seasons ； 3) A certain number of portable and cart-mounted small fire extinguishing devices should be available within the tank area ； 4) Greening is strictly prohibited within the fire dike of the tank area; gravel or a concrete floor should be laid instead ； 5) Trees that could hinder firefighting operations are strictly prohibited from being planted on the side of the tank farm where the firefighting roads are located ； 6) The circular fire roads in the tank area must be unobstructed to ensure the passage of fire trucks in emergency situations. 4. Storage tanks and tank accessories 1) Storage tanks for flammable liquid materials must all be floating-roof tanks; fixed-roof tanks should be equipped with breather valves and modern corrugated plate-type flame arresters ； 2) When a secondary dehydration device is used for the storage tank, the valve at the base of the tank cannot remain open, and the dehydration system must be equipped with a heat tracing line. 5. Instrumentation in the tank area: 1) Flammable liquid storage tanks should be equipped with level gauges and high/low level alarm systems ； 2) Liquid hydrocarbon spheres and liquid ammonia spheres shall be equipped with level gauges, pressure gauges, safety valves, and high-level alarms ； 3) Flammable gas detection and alarm devices shall be installed in the combustible liquid storage areas, liquid hydrocarbon storage areas, and unloading pump rooms. 6. Lightning and static electricity protection in the tank area: 1) The tank area and unloading platforms must be equipped with lightning and static electricity protection grounding systems; there should be no less than 2 grounding points for the storage tanks, and the grounding wires should allow for easy connection and disconnection. The grounding resistance should not exceed 10Ω ； 2) The independent lightning rods in the tank area and platforms must meet the specification requirements ； 3) Storage tanks and pipelines for storing and transporting flammable liquids must have reliable anti-static grounding, with a grounding resistance not exceeding 100Ω. III. Safety Technical Requirements 1. The tank area should be under semi-enclosed management; gateposts should be installed at the tank area and at the railway entrance. The ammonium sulfate storage area should be separated from the tank area, and unauthorized personnel and vehicles are strictly prohibited from entering the tank area and platforms. Strict fire control measures must be implemented ； 2. Vehicles permitted to enter the platform area to unload raw materials such as liquid ammonia and liquid caustic soda must strictly comply with the original safety regulations for unloading hazardous materials from tank trucks issued by Yingshan Petrochemical Plant. Personnel stationed at the platform should carry out thorough inspections and supervision during the unloading process, and it is strictly prohibited for outsiders to use the pipelines, valves, instruments, etc. located in the tank area ； 3. Construction activities for the expansion and renovation of tank areas must strictly comply with the \"Safety Management Regulations for Construction while Production is Ongoing.\" Safety measures should be established, and necessary safety isolation procedures should be implemented. Strict supervision of safety in ten key operational tasks such as hot work and work inside equipment, as well as proper management of safety operation permits, are required. The safety responsibilities of the construction management department, the utility engineering department, and the construction contractors must also be fulfilled ； 4. Improve the \"one-post, one-responsibility\" system for safe production in all positions within the tank area; promptly revise the \"Safety Technical Regulations\", \"Operational Procedures\", and \"Emergency Plans\" and ensure their strict implementation. In particular, it is necessary to take proper measures to prevent fires, explosions, overheating, overpressure, and excessive storage during hot seasons, as well as to address issues related to freezing, condensation, and slippage in winter, in order to avoid serious and catastrophic accidents ； 5. The tanks shall be marked with their identification numbers and the names of the materials stored in them, while the pipelines should be labeled with their pipeline identification numbers, the names of the materials, and their direction of flow ； 6. Establish specific inspection requirements, strictly implement the post inspection system, and standardize the inspection items ； 7. Kanban management should be implemented for the key operations related to materials entering and leaving the tank area; the status of valves on-site must be clearly indicated or displayed in the control room to prevent misoperations, and safety measures should be in place to avoid such misoperations as well as overfilling and spills ； 8. When an alarm for high or low liquid level occurs in the storage tank, or when a combustible gas alarm goes off, it is necessary to go to the site for inspection and confirmation, and take appropriate measures; it is strictly prohibited to ignore such alarms arbitrarily. 9. Water accumulated inside the flood control dike during the rainy season should be drained promptly, and the outlet should be closed immediately after drainage ； 10. The instruments and safety facilities in the tank area must be maintained promptly to ensure they are in good condition. IV. Requirements for Safe Operation 1. Requirements for unloading materials from trucks 1) Once the truck or tank vehicle arrives at the site, it must follow the instructions of the personnel responsible for unloading at the platform. The truck escort is only tasked with connecting the hoses on the vehicle; they are not allowed to operate the equipment, valves, or other components at the unloading platform. The personnel assigned to unloading in the tank area are responsible for connecting the pipelines and operating the valves ； 2) The discharge conduit must be properly supported and fixed; the connection between the discharge conduit and the valve should be secure. The valve should be opened gradually, and if there is any leakage, it must be resolved before discharge can resume ； 3) The unloading speed of flammable and explosive materials must not be too fast, and static electricity discharge facilities must be available ； Once the liquid level in the storage tank reaches the safe level, forced discharge into the tank is prohibited ； 4) Throughout the unloading process, the driver and the escort are not allowed to leave their posts without permission; they are also prohibited from smoking, drinking, sleeping, or chatting in the cab. The escort must remain on site throughout to ensure safety supervision ； 5) Stop the unloading of flammable and explosive materials in the event of lightning strikes, storms, or fires in the vicinity ； 6) The material inside the tank truck must be completely unloaded, after which the valves should be closed, and the unloading ducts and support frames should be stored away ； 7) It is strictly prohibited to clean and handle residual hazardous materials in the production facility area or at the unloading platforms; it is also not allowed to use the fire-fighting water or production water available in those areas to wash vehicles ； 8) After unloading is complete, the tank truck should immediately leave the unloading platform. 2. Requirements for unloading trains from tank cars: 1) A dedicated railway line is required; the rail insulation joints at the entrance to this dedicated line must be in good condition to prevent stray currents from entering the working area ； The grounding device of the dedicated line must be in good condition, with a grounding resistance not exceeding 30Ω ； After the tank truck is disassembled and aligned, fixing and anti-slip equipment must be in place. 2) Unloading trestle and unloading control panel: The flexible hoses are lightweight and can be balanced as needed ； Valves, flange connections, rotary joints, sleeves or bellows compensators, hose fittings, etc., should all be airtight and leak-free ； The lighting fixtures, wires, and signal communication devices on the pier should be in good condition, without any breaks, damage, or short circuits ； The walkways, ladders, or extendable ladders on the pier should be sturdy; they need to be inspected once a month, and any damage or breaks should be repaired promptly ； The cross-wiring and grounding of the aggregate pipe sets must be in good condition; the grounding resistance should be less than 30Ω, and there should be no fewer than two sets. 3) Requirements for unloading and feeding operations: Operators should wear anti-static work clothing, avoid using tools that generate sparks, and use explosion-proof flashlights for lighting ； The initial unloading speed for materials that are prone to generating static electricity should be less than 1 m/s, and thereafter it should be less than 4 m/s ； Close the valves promptly when unloading is nearly complete, to avoid excessive residual material as well as prevent the intake of gases ； When the temperature is too high, approaching or exceeding the flash point of the material, cooling measures should be taken, and the access holes should be covered with asbestos blankets soaked in water ； Unloading of flammable materials is prohibited during thunderstorms ； During the unloading process, it is necessary to regularly check whether there are any leaks in the unloading pipes, valves, and other related systems. If material leakage occurs, appropriate protective equipment and gas protection gear must be worn to carry out repairs; if necessary, unloading should be stopped to address the issue ； Before unloading and feeding the material, carefully check the unloading process repeatedly to prevent mixing of materials ； Once the work is completed, return all the equipment used for unloading to their proper places and dismantle the work line trestle. V. Safety Management Requirements 1. Floor surfaces 1) The cement floor surfaces within the fire dikes of the tank area must be free of cracks and pits; settlement joints should be filled and smoothed with asbestos and cement to prevent water or material seepage as well as the accumulation of materials ； 2) The area outside the fire dike of the tank farm should have weeds removed regularly, and dead grass and leaves cleared promptly ； 3) Flammable materials are not allowed to be piled up within the tank area. 2. Water seal wells and drainage gates 1) Water seal wells are located outside the fire dike; they are used to collect any material that leaks from storage tanks, thereby preventing the spread of fire from such materials ； 2) The water seal well should be leak-proof, with a water seal layer thickness of not less than 0.25 m; the sedimentation layer should also have a thickness of not less than 0.25 m. Regularly check the liquid level in the water seal well; if floating materials are detected, identify the cause and remove them promptly ； 3) The drainage gates must be in good condition and reliable; a designated person should be responsible for operating them, opening them during rain and closing them when necessary, and this task should be included in the shift handover procedures. 3. Fire dike: 1) Inspect it once a month; any cracks, collapses, or dry grass should be repaired or removed promptly ； 2) The reserved holes for pipes passing through the embankment should be sealed with non-combustible materials, and their sealing condition should be checked regularly ； 3) Ensure that the drainage holes are unobstructed and that they do not leak when closed; any bricks that have fallen out or cracks that have appeared must be repaired promptly. 4. Storage tank foundation: 1) Conduct regular inspections once a year to check for uniform settlement, uneven settlement, total settlement amount, and the slope of the conical surface of the storage tank foundation; any issues found must be addressed promptly ； 2) When the slope protection stones become loose or develop cracks, they should be fixed and grouted promptly ； 3) Regularly check the seepage pipes under the sand cushion to ensure that no material is leaking out; once any leakage is detected, immediate action should be taken to clean the tank and carry out repairs. 5. Tank body: 1) During regular cleaning of the storage tank, the thickness of the tank bottom should be measured, and defects such as cracks and pores in the bottom should be inspected; if any issues are found, the tank must be cleaned and repaired ； 2) During regular cleaning of the storage tank, the remaining corrosion thickness of the tank wall must be checked; if any issues are found, protective measures must be taken or the tank must be repaired, and if necessary, it must be scrapped ； 3) The weld on the top of the tank is in good condition, with no air leakage. There are no cracks or detachment at the joints of the framework and the \"weak roof\"; the roof slab should not be uneven or deformed, allowing water to accumulate ； 4) The internal floating disk remains balanced at any position, without tilting, rotating, getting stuck, or being compressed. The floating disk shows no leaks, the ring seal is intact, with no folding or detachment. 6. Storage tank accessories: 1) The breather valve should be inspected once a week during cold seasons, and once a month in other seasons; it must be inspected immediately in cases of strong winds, heavy rain, or sudden temperature drops. In the event of blockage or poor functioning, it should be cleared or replaced promptly ； 2) The safety valve should be inspected once per quarter, and calibrated immediately if there is any leakage ； 3) The flame arrester should be inspected at least once per quarter, and at least once per month during cold seasons. The passages between the radiator fins must remain clean and unobstructed, free from dust and decay, and should be cleaned regularly. The gaskets are tightly fitted and securely installed, with no corrosion on the bolts ； 4) The fire foam generator shall be inspected once a month to ensure that the glass is undamaged, it is securely fixed with no leaks, and the gaskets are in good condition without signs of aging or damage ； 5) The sewage pipe should be inspected at least once per quarter; the valves must not leak and should operate smoothly ； 6) When the heating coil is not in use, drain the water and check for any leaks. During winter use, perform a pressure test to check for any cracks or perforations. In conjunction with the inspection or cleaning of the tank, tighten the supports for the heating tubes, and inspect all valves and traps to ensure they operate smoothly without any leaks ； 7) There are no cracks or deformations at the inlet and outlet connection pipes; the valves are airtight, operate smoothly, and the supports are secure ； 8) Ladders, platforms, and railings must be securely installed so as not to wobble; they should have an adequate safety height, and anti-slip measures must be in place during winter ； 9) The tank body is made of flame-retardant materials for corrosion protection and insulation; rainwater, spray water, and surface water must not wet the insulation material. 7. Lightning and static electricity protection grounding: 1) Before the arrival of the thunderstorm season each year, the grounding system should be inspected; any deficiencies found must be corrected, and the grounding wires must not be loose or corroded ； 2) For the down conductor that leads directly to ground from the grounding clip on the tank wall, it is necessary to check whether there is any loosening or rusting on the surfaces of the bolts and connectors; if so, they should be cleaned and tightened promptly ； 3) Check once a year whether the potential connection device between the floating disk and the tank body of external and internal floating roofs is in good condition, and whether the soft copper wires are intact and free from twists ； 4) During construction on the ground or underground, close supervision of the grounding electrodes is required; if it may affect grounding, inspections and measurements should be carried out. 8. Safety monitoring equipment such as high and low liquid level alarms, thermometers, pressure gauges, level gauges, and combustible gas detectors should be regularly inspected and calibrated to ensure they are in good working condition and ready for use. As petrochemical enterprises store increasing amounts of flammable and explosive materials, and as the variety of such materials grows, even the slightest carelessness can lead to fires and explosions, resulting in severe consequences. Therefore, safety precautions should be taken in all aspects such as process design requirements, safety management requirements, safety technical requirements, tank farm management requirements, and loading/unloading operations. It is also necessary to strengthen accident-prevention drills for operators at various positions in order to improve their ability to handle accidents. As long as we master various preventive measures and strictly follow all safety operation procedures and safety management systems, we can prevent or avoid accidents and minimize the impact of such incidents.