Storage Tanks:

　　Our company possesses the qualifications and capabilities to design and manufacture Class I, II, and III pressure vessel storage tanks. These are widely used in the petrochemical, refining, fertilizer, pharmaceutical, and cement industries. We can also design and manufacture various non-standard storage tanks according to customer's specific needs.

　　When you need them, Gongshen Group will quickly design and manufacture high-quality products.

　　Storage Tanks

　　1. Suitable for molding large and extra-large parts

　　In most plastic molding processes, both the plastic and the mold are under considerable pressure during the molding process. For example, in widely used injection molding, compression molding, extrusion, and blow molding, etc. Therefore, when using these molding processes to produce large plastic parts, not only must molds capable of withstanding high pressure be used, making the molds heavy and complex, but the plastic molding equipment must also be designed and manufactured to be very strong. The difficulty of processing and manufacturing the machine and mold increases accordingly, and the cost increases. In contrast, because the rotomolding process only requires the frame strength to support the weight of the material, mold, and frame itself, and the closing force to prevent material leakage, even for large and extra-large plastic parts such as corrosion-resistant storage tanks, it is not necessary to use very heavy equipment and molds. The processing and manufacturing of the machine and mold is very convenient, the manufacturing cycle is short, and the cost is low. 1. Theoretically, there is almost no upper limit on the size of parts formed using the rotomolding process. However, to produce such large plastic containers, using blow molding would require extremely expensive and large blow molding equipment.

　　2. Corrosion-resistant storage tanks, etc., are suitable for multiple varieties

　　Small-batch plastic product production. Because the rotomolding mold is not subjected to external forces, the mold is simple, inexpensive, and easy to manufacture. In addition, rotomolding equipment also has greater mobility. A single rotomolding machine can be equipped with a large mold or multiple small molds; it can not only mold parts of different sizes but can also simultaneously mold parts of very different sizes and shapes. As long as the raw materials used for the rotomolded products are the same and the product thickness is similar, they can all be rotomolded simultaneously. Therefore, the rotomolding process for corrosion-resistant storage tanks has greater flexibility than other molding methods. 3. Rotomolding is very easy to change the color of the product. In rotomolding, the material is added directly to the mold each time, so all the material enters the product. After the product is taken out of the mold, the material for the next molding is added. Therefore, when we need to change the color of the product, it will not waste any raw materials, nor will it take time to clean the machine and mold for corrosion-resistant storage tanks. When we use multiple molds to rotomold the same type of plastic product, we can also add materials of different colors to different molds and simultaneously rotomold plastic products of different colors.

　　Processing Technology

　　(1) Processing technology of polyethylene storage tanks:

　　Polyethylene (PE) horizontal storage tanks use pure polyethylene (linear low-density polyethylene LLDPE, high-density polyethylene HDPE) as raw materials and are integrally molded using the rotomolding process.

　　(2) Processing technology of steel-lined plastic storage tanks:

　　Steel-lined plastic vertical storage tanks, also known as tortoise-shell lined tanks (tortoise-shell lining—a combination of steel, mesh, and plastic), are the essence of steel-plastic composite products. They use a special rotomolding process. It involves welding a steel mesh (tortoise shell) to the surface of the steel body, using pure polyethylene (linear low-density polyethylene LLDPE, high-density polyethylene HDPE) as the raw material, and using the rotomolding process to organically combine the steel plate, steel mesh (tortoise shell), and polyethylene into one. The polyethylene adheres firmly to the surface of the steel body. The product has the advantages of no welding seams, no leakage, non-toxicity, anti-aging, impact resistance, corrosion resistance, long life, and compliance with hygiene standards. It compensates for the shortcomings of all-plastic rotomolded tanks, such as poor rigidity, low pressure resistance, and poor temperature resistance.

　　Classification Characteristics

　　Due to the different storage media, the forms of storage tanks are also diverse.

　　Classification by location: They can be divided into aboveground storage tanks, underground storage tanks, semi-underground storage tanks, offshore storage tanks, and underwater storage tanks.

　　Classification by oil type: They can be divided into crude oil storage tanks, fuel oil storage tanks, lubricating oil tanks, edible oil tanks, and fire water tanks.

　　Classification by use: They can be divided into production oil tanks and storage oil tanks.

　　Classification by form: They can be divided into vertical storage tanks and horizontal storage tanks.

　　Classification by structure: They can be divided into fixed-roof storage tanks, floating-roof storage tanks, and spherical storage tanks.

　　Classification by size: Tanks above 100m3 are large storage tanks, mostly vertical storage tanks; those below 100m3 are small storage tanks, mostly horizontal storage tanks.

　　According to the material of the storage tank: The materials required for storage tank projects are divided into tank body materials and auxiliary facility materials. Tank body materials can be divided into low-strength steel and high-strength steel according to tensile yield strength or tensile standard strength. High-strength steel is mostly used for storage tanks above 5000m3; auxiliary facilities (including wind bracing beams, locks, platforms, railings, etc.) all use ordinary carbon structural steel with lower strength. Other parts and accessories use other materials according to different uses. Commonly used domestic steel materials for manufacturing tank bodies include 20, 20R, 16Mn, 16MnR, and Q235 series, etc.

　　Structural Characteristics

　　Currently, the dome-roof storage tanks, floating-roof storage tanks, and horizontal storage tanks are widely used and have mature manufacturing and installation technologies in China.

　　Dome-roof type

　　A dome-roof storage tank is a steel container with a spherical crown-shaped top and a cylindrical body. Dome-roof storage tanks are simple to manufacture and inexpensive, so they are widely used in many industries at home and abroad. The commonly used volume is 1000-10000m3, and the large volume of dome-roof storage tanks in China has reached 30000m3.

　　Tank bottom: The tank bottom is assembled from steel plates. The steel plate in the center of the tank bottom is the central plate, and the steel plates around the periphery are the edge plates. The edge plates can be strip plates or arc plates. Generally, when the inner diameter of the storage tank is <16.5m, strip edge plates should be used; when the inner diameter of the storage tank is ≥16.5m, arc edge plates should be used.

　　Tank wall: The tank wall is made of multiple steel plates welded together, and is divided into sleeve type and straight type.

　　The circumferential welds of the sleeve-type tank wall plates are lap-jointed, and the longitudinal welds are butt-jointed. This type is mostly used for dome-roof tanks, and its advantage is that it is easy to assemble the plates of each circle, and the inverted installation method is safer.

　　The circumferential welds of the straight-type tank wall plates are butt-jointed. The advantage is that the overall tank wall has the same diameter from top to bottom, which is especially suitable for internal floating-roof tanks, but the assembly and installation requirements are higher and the difficulty is also greater.

　　Tank top: The tank top is made of several sector plates welded together into a spherical crown shape. The inside of the tank top is reinforced with flat steel, and the sector plates are lap-welded together. The entire tank top is welded to the angle steel ring (or lock) at the top of the tank wall as one piece.

　　Floating roof type

　　A floating roof tank consists of a floating roof floating on the surface of the medium and a vertical cylindrical tank wall. The floating roof rises and falls with the increase or decrease of the medium storage in the tank. There is an annular sealing device between the outer edge of the floating roof and the tank wall, and the medium in the tank is always directly covered by the internal floating roof, reducing the volatilization of the medium.

　　Tank bottom: The volume of floating roof tanks is generally large, and their bottom plates are all made of arched edge plates.

　　Tank wall: A straight-type tank wall is used, and the butt welds should be ground smooth to ensure a smooth inner surface. The upper part of the floating roof tank is open. To increase the stiffness of the wall plates, a wind-resistant ring beam and reinforcing ring should be set at the top of the tank wall according to the wind load in the area.

　　Floating roof: Floating roofs are divided into single-deck floating roofs, double-deck floating roofs, and pontoon-type floating roofs.

　　Single-deck floating roof: It consists of several independent compartments to form an annular pontoon, and its annular inner side is a single-deck top plate. The bottom of the single-deck top plate is reinforced with multiple annular steel rings. Its advantages are low cost and easy maintenance.

　　Double-deck floating roof: It consists of an upper deck plate, a lower deck plate, and a pontoon edge plate, and is divided into several independent annular compartments by radial and circumferential baffles. Its advantages are large buoyancy and good drainage effect.

　　Internal floating roof type

　　An internal floating roof tank is formed by adding a floating roof inside a dome-roof tank. Adding a floating roof inside the tank can reduce the volatilization loss of the medium, and the external dome can prevent rainwater, snow, and dust from entering the tank, ensuring the cleanliness of the medium in the tank. This type of tank is mainly used for storing light oils, such as gasoline and aviation kerosene. Internal floating roof tanks use straight-type tank walls, with the wall plates butt-welded, and the dome is made according to the requirements of dome-roof tanks. Currently, there are two types of internal floating roofs in China: one is a steel floating roof similar to that of a floating roof tank; the other is a prefabricated aluminum alloy floating roof.

　　Horizontal type

　　The volume of horizontal tanks is generally less than 100m3, and is usually used in production processes or gas stations. The circumferential welds of horizontal tanks are lap-jointed, and the longitudinal welds are butt-jointed. The ring plates are arranged alternately, taking an odd number, so that the diameters of the end caps are the same. The end caps of horizontal tanks are divided into flat end caps and dished end caps. Horizontal tanks with flat end caps can withstand 40kPa internal pressure, and horizontal tanks with dished end caps can withstand 0.2Mpa internal pressure. Underground horizontal tanks must be equipped with reinforcing rings, and the reinforcing rings are made of bent angle steel.

　　Design

　　1. Hazard analysis of large crude oil tank projects

　　1.1 Crude oil hazard analysis

　　Crude oil is a Class B flammable liquid, which is flammable; the explosive limit range is narrow, but the value is low, and it has a certain explosion hazard. At the same time, the easy boiling and overflowing property of crude oil should be paid special attention to during fire fighting.

　　1.2 Analysis of causes of fire and explosion accidents

　　The characteristics of crude oil determine that the fire and explosion hazard is the main and important hazard factor of large crude oil tanks. The three necessary conditions for a fire accident are: ignition source, combustible material, and air.

　　The problem of ignition source is mainly solved by strengthening management, and the problem of combustible material leakage must be prevented and controlled in the design process of the tank.

　　Leaked crude oil exposed to air constitutes combustible material. Crude oil leakage is relatively frequent during storage and transportation, mainly including oil leakage from the tank, dehydration leakage, equipment, pipeline, and valve damage leakage, and poor sealing causing oil and gas volatilization. In addition, there is also the possibility of large-scale leakage accidents such as tank bottom welding cracking and floating roof sinking.

　　Corrosion is one of the important factors causing leakage. Many oil leakage accidents caused by corrosion at the bottom of oil tanks have occurred at home and abroad. The preliminary investigation results of the internal corrosion of crude oil tanks [1] show that the corrosion of the tank bottom is serious, mostly ulcer-like pitting corrosion, mainly occurring in the heat-affected zone of welding, depressions, and deformations. The corrosion of the tank top is secondary, which is uneven overall corrosion with pitting corrosion. The corrosion of the tank wall is relatively light, which is uniform pitting corrosion, mainly occurring at the oil-water interface and the oil-air interface. Relatively speaking, the external corrosion of the tank bottom is more serious, mainly occurring on the side where the edge plate contacts the ring beam foundation.

　　Floating roof sinking accidents are one of the very taboo serious and malignant equipment accidents during the production operation of floating roof oil tanks. The occurrence of such accidents, on the one hand, reflects the serious defects in design, construction, and management, and on the other hand, will cause a large amount of crude oil leakage, seriously affecting production, polluting the environment, and constituting a fire hazard.

　　2. Main safety issues and countermeasures in the design of large crude oil tanks

　　2.1 Tank foundation and base

　　Tank project foundation investigation and tank foundation design are the fundamental guarantee for ensuring the safe operation of large tanks. According to the standards of the petrochemical industry [2], engineering geological investigation must be carried out during the project site selection process. For general foundations, soft soil foundations, mountain foundations, and special soil foundations, the situation should be investigated separately, and corresponding foundation treatment methods should be proposed. At the same time, seismic effect evaluation of the site and foundation should also be carried out to avoid building on foundations with uneven softness and hardness or within the influence range of active geological faults.

　　Common tank foundation forms include annular wall (beam) type, outer annular wall (beam) type, and slope protection type. The selection should be based on geological conditions. The tank foundation must have sufficient overall stability, uniformity, and sufficient flexural rigidity in the plane. The rigidity of the foundation structure directly below the tank wall should be strengthened. The foundation bed supporting the bottom plate should be flexible enough to absorb welding deformation. It is advisable to set up waterproof and oil-proof layers and oil leakage signal pipes. The distance between the groundwater level and the top surface of the foundation must not be less than the height that capillary water can reach (generally 2m)[3].

　　Safe Operation

　　Safety Precautions

　　1. Operation of this equipment must be performed by operators who have undergone strict and systematic training, passed examinations (written and practical operation), and obtained equipment operation certificates. Any personnel who have not been trained are strictly prohibited from operating the equipment.

　　2. Do not operate the equipment if unfamiliar with its performance; do not operate the equipment if safety protective equipment is not fully worn; do not operate the equipment if you have not fully understood and mastered the equipment operation procedures.

　　3. On-site professional and technical personnel and security personnel have the right to stop and correct unsafe behaviors of others, such as violating regulations and taking risks; they have the right to refuse commands, dispatching, and arrangements that do not meet safety requirements or violate regulations.

　　4. All personnel entering the unloading area are prohibited from bringing communication tools! Static electricity must be discharged at the static electricity discharge point!

　　5. Before starting work, check whether the insulation pads in front of each control cabinet are intact and dry. Before starting the equipment, use a test pen to check whether the equipment has any leakage.

　　6. In case of an emergency, press the red emergency stop switch, turn off the equipment's main power supply, immediately notify the equipment maintenance personnel to handle it, and notify the relevant management personnel and equipment personnel. Do not handle it without authorization.

　　7. Under no circumstances should the equipment's safety protection devices be removed, damaged, short-circuited, or used for other purposes for any reason, rendering the safety protection facilities ineffective.

　　8. Do not operate the equipment after consuming any drugs or beverages that reduce attention or cause mental confusion.

　　9. Trainees are strictly prohibited from operating the equipment alone without the supervision of a team leader or master!

　　10. It is strictly forbidden to intervene inside the equipment during operation when the process is immature, unreasonable, or when all or part of the body needs to be inside the equipment during automatic operation.

　　11. Do not start the machine if there is water leakage in the factory building or water accumulation around the equipment.

　　12. If various lubricating oils and liquid media are spilled, they must be wiped up immediately. Do not operate in a slippery environment.

　　13. Do not place items in the control cabinet or operating table to prevent short circuits, injuries, and equipment damage.

　　14. When repairing or cleaning the equipment, the operator must turn off the equipment's power supply and hang a safety warning sign that says "Do not close the switch, someone is working." Operation must be performed under the supervision of a designated person; do not operate alone! Do not use chemical fiber materials to wipe or clean the equipment!

　　15. The JIT procurement administrator shall issue a written notice of incoming and unloading materials one day in advance. The Human Resources Department shall arrange security for the unloading area. The production company shall prepare for unloading. Tank trucks must be equipped with flame arresters. Do not expose to strong sunlight! Do not unload during thunderstorms! Do not allow material transport trucks to stay at the company gate for more than 60 minutes!

　　16. When entering the cyclopentane area, wear anti-static clothing and protective equipment. Do not wear chemical fiber clothing, change clothes, or wear shoes with nails in the cyclopentane area.

　　17. Do not bring pagers, mobile phones, or flammable and explosive items into the unloading area. Do not use iron objects to strike in the cyclopentane area.

　　18. In case of leakage, immediately remove nearby fire sources, and quickly organize the recovery into containers. If there is a fire, water can be sprayed to cool the container. If possible, move the container from the fire scene to an open area. If the container in the fire scene has changed color or sounds are coming from the safety pressure relief device, evacuate immediately. Extinguishing agents can be sand, dry powder, or carbon dioxide; water is ineffective.

　　19. If cyclopentane contaminates clothing, thoroughly wash the skin with soapy water and clean water.

　　20. If cyclopentane splashes into the eyes, lift the eyelids and rinse with running water or saline, and seek medical attention.

　　21. If cyclopentane is inhaled, immediately leave the scene to a place with fresh air, keep the respiratory tract open, and if breathing is difficult, immediately give oxygen. If breathing stops, immediately perform artificial respiration and seek medical attention.

　　22. If cyclopentane is swallowed, drink plenty of warm water, induce vomiting, and seek medical attention.

　　23. During holidays and specific periods, a designated person must be responsible for duty to prevent accidents.

　　Before Unloading

　　1. Security personnel and unloading operators arrive at the scene 15 minutes in advance. Security personnel prepare for security! Restricted area is 60 meters from the unloading point! Each passageway is guarded by a designated person, and all vehicles and personnel are prohibited from passing through, and all open flames are prohibited. The operator first records the liquid level data of the storage tank level indicator! Prepare all work before unloading, such as storage tank pressure relief, nitrogen preparation, cotton yarn preparation, copper wrench preparation, etc.!

　　2. After receiving the notification that the unloading operator is ready, the security guard will pass the information to the front gate, and the front gate security guard will notify the tank truck to enter the park and go directly to the unloading point.

　　3. The filling work is carried out by professional and technical personnel and is uniformly commanded, and is carried out with the cooperation of professionally trained maintenance personnel and operators. All personnel entering the site, tanker drivers, and security personnel outside the site should absolutely obey the command of professional and technical personnel.

　　4. Security personnel guide the tank truck to the unloading platform, park, and turn off the engine!

　　5. Equipped with 6 35KG dry powder fire extinguishers and sufficient towels. Prepare for leakage emergency measures: protective sand, cotton yarn, etc.

　　6. Professional personnel check that all fire extinguishers are well sealed, and the certificates are valid. Check that the personnel participating in the filling do not carry fire or cigarettes, etc. All personnel participating in the filling must wear anti-static clothing and anti-static shoes.

　　7. Before commencing work, professional technicians will brief all personnel involved in the filling process on the entire procedure and precautions. Work assignments will be made. The material discharge operator will use a copper wrench to remove the feed port seal and securely connect the tank truck outlet valve to the storage tank inlet, ensuring no leaks.

　　8. Correctly and securely connect the tank area grounding wire to the tank truck grounding device! Route the on-site nitrogen hose to the unloading area for standby use.

　　9. Unloading is prohibited in the event of lightning or other severe weather!

　　III. During Unloading

　　1. Upon receiving instructions, open the tank truck valve to begin unloading. Prepare a portable cyclopentane hand-held alarm detector to test for leaks throughout the filling process. A designated person will monitor the process. In case of a leak, immediately close the valve and carry out repairs.

　　2. During unloading, the material discharge operator must not leave the unloading valve and must be prepared for emergencies at all times. In case of a leak, immediately close the tank truck outlet valve!

　　3. Security personnel will immediately handle the leaked cyclopentane raw material. Minor leaks: Use nitrogen to purge and absorb with cotton gauze, place in the drip pan, and allow to evaporate in a ventilated area. Major leaks: Transfer to prepared empty barrels using a dedicated container and quickly move to the designated storage area!

　　4. After 50 minutes of unloading, the material discharge operator should pay attention to the pressure changes in the tank truck.

　　5. When the unloading from the tank truck is confirmed complete, close the tank truck valve.

　　6. Pay attention to whether the control cabinet high-level alarm (90%) is triggered. If so, stop unloading immediately.

　　IV. After Tank Filling

　　1. When the relative pressure in the tank truck drops to zero, maintain pressure balance, and unloading is complete. Simultaneously record the data from the storage tank level indicator!

　　2. Disconnect the tank truck and tank area piping, raise the tank area piping, allow the residual cyclopentane in the hose to flow into the storage tank, purge the hose and surrounding gas with nitrogen, and close the storage tank inlet valve and inlet.

　　3. Return the storage tank unloading pipe and vent pipe to the bracket and close the pipe valve.

　　4. After purging the unloading area with nitrogen for several minutes, reset the fire extinguisher and lift the cordoned-off area.

　　V. Other Precautions

　　1. During unloading operations, smoking, bringing fire sources, and using mobile phones are strictly prohibited in the unloading area. Tools used should be made of copper or other explosion-proof materials.

　　2. Cyclopentane unloading or operations involving exposed cyclopentane are prohibited during thunderstorms.

　　3. When the cyclopentane transport truck arrives at the front gate, the front gate security personnel will immediately notify the safety administrator.

　　Ten Regulations

　　1. Check levels on time, inspect at designated points, and record carefully.

　　2. Dehydration of oil products should be attended to, to prevent oil spills.

　　3. Oil product receipt and payment should follow established procedures to prevent errors.

　　4. When switching oil tanks, open before closing to prevent pressure buildup.

　　5. After cleaning the tank, carefully inspect before putting it into use.

　　6. On-site handover should be strict and careful to avoid errors.

　　7. Regularly inspect the breather valve to prevent collapse.

　　8. Heavy oil heating should not exceed the limit to prevent sudden boiling.

　　9. After use, pipelines should be processed promptly to prevent freezing.

　　10. New tanks should be inspected and signed off before oil (material) can be introduced.

　　Inspection and Maintenance

　　For the storage of hazardous media, we have strict inspection and maintenance procedures for fiberglass reinforced plastic (FRP) storage tanks, following these standards:

　　1. Tanks storing combustible gases and flammable liquids should be equipped with necessary fire-fighting equipment. Smoking, open flames for lighting or heating, and bringing ignition sources into the tank area are strictly prohibited.

　　2. For tanks storing flammable, explosive, toxic, or corrosive media, the relevant regulations for hazardous materials management must be strictly followed.

　　3. Before inspection and repair of storage tanks, the power supply to related electrical equipment must be cut off, and equipment handover procedures must be completed.

　　4. After the internal media of the storage tank is completely drained, the inlet and outlet valves should be closed, or blind plates should be installed to isolate the connected pipelines and equipment. Clear isolation markings should be provided.

　　5. Tanks containing flammable, corrosive, toxic, or asphyxiating media must be treated by displacement, neutralization, disinfection, and cleaning. After treatment, analysis and testing should be conducted, and the analysis results should meet the relevant specifications and standards. Air displacement is strictly prohibited for tanks containing flammable media.

　　6. A permit must be obtained for work inside the tank. If work is interrupted for a longer period, a new permit must be obtained.

　　7. A sample should be analyzed for oxygen content 30 minutes before entering the tank for work; the oxygen content should be between 18-23% (by volume).

　　8. When cleaning toxic and corrosive residues inside the tank, appropriate personal protective equipment must be worn.

　　9. Scaffolds and lifting devices must be sturdy and reliable. Throwing materials and tools inside and outside the tank is strictly prohibited during operation to ensure safe operation.

　　10. Tank lighting should use explosion-proof lamps with a voltage not exceeding 24V.

　　11. If hot work is required inside the tank, a hot work permit must be obtained.

　　12. Tank work must have a supervisor and reliable communication measures.

　　13. Upon completion, the maintenance personnel and supervisor will jointly inspect the inside and outside of the tank. After confirmation, the supervisor will sign the tank entry permit before closing the manholes.

　　14. When draining water after pressure testing, the system must be connected to the atmosphere to prevent vacuum formation.

　　General Precautions

　　Oil storage tanks and tank areas store large quantities of oil, posing significant fire and explosion risks. Fire and explosion prevention systems must be established in accordance with relevant regulations. Regular fire prevention patrols and strict fire safety management are essential to ensure fire safety.

　　(1) Fire and explosion prevention for oil storage tanks and tank areas should comply with GB50183 and GB50074 regulations. Low-expansion air foam fire extinguishing systems should comply with GB50151 regulations.

　　(2) The tank area should be kept clean, with no dry grass, oil stains, or combustibles within the fire dike.

　　(3) The tank area drainage system should have a water seal well; valves should be installed on the drainage pipes outside the fire dike; when draining oil tanks, a designated person should supervise and promptly remove residual oil from the water seal well.

　　(4) Non-explosion-proof electrical equipment and high-voltage overhead lines should not be installed in the tank area.

　　(5) Fire dikes should be installed in the tank area as per regulations, and these dikes should be maintained in good condition.

　　(6) The top of the oil storage tank should be free of oil stains and standing water. Insulation measures should be taken for the oil storage tank's inlet and outlet pipelines and valves.

　　(7) The light transmission holes, gauging hole covers, and gaskets on the top of the oil storage tank should be kept intact, and the covers should be tightly sealed. The oil level gauge should be fitted with a spark-proof metal gasket.

　　(8) Flame arresters should be installed at the base of the breather valve and pressure relief valve on the oil storage tank. Flame arresters should be inspected at least once per quarter.

　　(9) Flexible hose compensators should be installed on the oil storage tank's inlet and outlet pipelines.

　　(10) Steel oil storage tanks should be equipped with lightning protection and anti-static grounding devices, with a grounding resistance of no more than 10Ω. Grounding points should be installed at least every 30m along the bottom edge of the tank, with no fewer than two grounding points for a single tank.

　　(11) A comprehensive inspection of the lightning protection and anti-static grounding devices should be conducted annually in the spring, and the measured grounding resistance should meet the requirements.

　　(12) The pontoon of a floating roof tank should be connected to the tank wall with two soft copper wires with a cross-sectional area of no less than 25mm2.

　　(13) The oil storage tank's oil level should operate within the safe tank level.

　　(14) When the condensed oil level is higher than the heating coil, the steam riser pipe should be used for heating first. After the condensed oil melts, the steam coil can then be used for heating.

　　(15) Do not wear synthetic fiber clothing or shoes with iron nails onto the tank. Do not turn on/off non-explosion-proof flashlights on the tank top.

　　(16) Hot work and cleaning operations on oil pipelines in the tank area should follow industry regulations.

　　(17) In case of an oil storage tank fire, immediately report the incident and stop all operations on the burning oil tank. Organize fire extinguishing and activate the emergency plan in a timely manner.

　　Maintenance and Repair

　　To ensure safe production and equipment operation, extend equipment lifespan, and improve labor productivity, regular inspection and maintenance of operating machinery and equipment are necessary to prevent mechanical failures that could affect production or cause accidents resulting in casualties. Based on actual production, safe operating procedures, and safe maintenance management systems, this annual tank maintenance and repair plan has been developed.

　　The general maintenance cycle for tanks is: intermediate repair 60-120 days, major repair 12 months. Intermediate repair: Eliminate leaks, spills, drips, and seepage.

　　Cleaning or replacement of liquid level gauges, repair or replacement of inlet, outlet, and drain valves, cleaning of cooling water coils. Inspection and repair of safety valves and flame arresters. Repair of anti-corrosion and insulation layers. Major repair: Includes intermediate repair items, repair of tank internals, repair or replacement of sections with cracks or severe corrosion. Repair can be done using high-polymer composite materials. After repair or replacement of sections, leak testing or hydraulic testing is required according to internal and external inspection requirements. Comprehensive derusting and insulation. Addressing other issues found during internal and external inspections of the tank.

　　Repair methods and quality standards for tank repairs, such as opening holes, welding, and replacing sections, should be based on relevant standards and regulations, with specific construction plans developed and approved by the unit's technical manager. Materials (base materials, welding rods, welding wires, fluxes, etc.) and valves used in repairs should have quality certificates. When using old materials, valves, and fasteners, they must be inspected and approved before use. Fasteners for assembling tanks should be coated with lubricating materials, and bolts should be tightened diagonally in sequence. Non-metallic gaskets should generally not be reused. When selecting gaskets, the corrosiveness of the medium should be considered. After repair and inspection, anti-corrosion and insulation work can be carried out.

　　1. Grinding method to eliminate defects

　　2. Welding or patching

　　3. Section replacement

　　4. Excavation and repair

　　5. Rapid leak plugging

　　Traditional on-site welding for these issues is not only ineffective but also highly dangerous. Replacing the medium before welding is time-consuming, labor-intensive, and causes significant production losses. American Megahertz Technology uses appropriate technical products for different equipment, operating conditions, and corrosion and leakage forms, allowing for quick, simple, and effective equipment protection. The high-performance composite materials' chemical corrosion resistance and bonding properties avoid the drawbacks of traditional welding repairs, extending the lifespan of repaired equipment beyond that of new equipment. This fundamentally addresses the root causes of corrosion and leakage, helping companies improve equipment management, reduce maintenance costs, and enhance competitiveness.

　　Applications

　　Steel storage tanks are sealed steel containers used to store liquids or gases. Corrosion-resistant tank engineering is an essential and important infrastructure for industries such as petroleum, chemical, grain and oil, food, fire protection, transportation, metallurgy, and national defense. Steel storage tanks of various sizes are indispensable in our economic life, playing an irreplaceable role in the development of the national economy. Steel storage tanks are specialized equipment for storing various liquid (or gaseous) raw materials and finished products. For many enterprises, production is impossible without storage tanks, especially for national strategic material reserves, which rely on storage tanks of various capacities and types, including corrosion-resistant tanks. China's oil storage facilities are mainly above-ground tanks, mostly with metal structures. Therefore, this website will focus on introducing basic knowledge of commonly used dome-roof tanks, internal floating-roof tanks, horizontal tanks, and corrosion-resistant tanks in China.

　　Fiberglass Type

　　Jinghui Fiberglass Storage Tank

　　Jinghui Fiberglass Storage Tank (10 images) Fiberglass storage tanks have the following characteristics:

　　(1)Lightweight and high strength. The relative density is between 1.5 and 2.0, only 1/4 to 1/5 that of carbon steel, but the tensile strength is close to or even exceeds that of carbon steel, and the specific strength is comparable to that of high-grade alloy steel. Therefore, it has excellent effects in aerospace, rockets, spacecraft, high-pressure containers, and other products where weight reduction is required. The tensile, bending, and compressive strength of some epoxy FRP can reach more than 400 MPa. The density, strength, and specific strength of some materials are shown in Table 1-1.

　　(2)Good corrosion resistance

　　FRP is an excellent corrosion-resistant material, with good resistance to atmosphere, water, and common concentrations of acids, alkalis, salts, and various oils and solvents. It has been applied to all aspects of chemical corrosion protection and is replacing carbon steel, stainless steel, wood, and non-ferrous metals.

　　(3)Good electrical properties

　　It is an excellent insulating material used to manufacture insulators. It maintains good dielectric properties even at high frequencies. It has good microwave permeability and is widely used in radar antenna radomes.

　　(4)Good thermal properties

　　FRP has low thermal conductivity, 1.25~1.67 kJ/(m·h·K) at room temperature, only 1/100 to 1/1000 that of metal, making it an excellent heat insulation material. Under conditions of instantaneous ultra-high temperature, it is an ideal heat protection and ablation-resistant material, capable of protecting spacecraft from high-speed airflow erosion at temperatures above 2000℃.

　　(5)Good designability

　　①Various structural products can be flexibly designed according to needs to meet usage requirements, ensuring good product integrity.

　　②Materials can be fully selected to meet product performance, such as designing corrosion-resistant, instantaneous high-temperature resistant, products with particularly high strength in a certain direction, good dielectric properties, etc.

　　(6)Excellent processability

　　①Molding processes can be flexibly selected according to product shape, technical requirements, use, and quantity.

　　②The process is simple, allowing for one-time molding with outstanding economic efficiency. This is particularly advantageous for products with complex shapes, difficult molding, and small quantities.

　　Polyethylene Type

　　Polyethylene is abbreviated as PE. The maximum application temperature is 60℃ for low-density polyethylene and 70℃ for high-density polyethylene. The minimum application temperature is -70℃. It has advantages such as no welding seams, no leakage, non-toxicity, aging resistance, impact resistance, corrosion resistance, long lifespan, and compliance with hygiene standards. It compensates for the shortcomings of all-plastic rotomolding tanks, such as poor rigidity, low pressure resistance, and poor temperature resistance. The inner lining is flat, smooth, and strong. Compared with traditional steel-lined plastic plate tanks, steel-lined rubber tanks, and steel-lined fiberglass tanks, it has better corrosion resistance, no leakage, no peeling, wear resistance, pressure resistance, higher temperature resistance, and longer lifespan. Its price is lower than that of traditional tanks of the same specifications, making it an ideal container for storing corrosive liquids. Therefore, it is an extremely excellent corrosion-resistant storage tank. Steel-lined plastic vertical storage tanks also have the advantages of easy installation, small footprint, and the ability to be made into shapes required by users. The integrity of extra-large steel-lined plastic storage tanks is even more prominent, surpassing other tank manufacturing processes.

　　Substances that can be stored

　　(1)Inorganic acids: (dilute sulfuric acid, dilute nitric acid, hydrochloric acid, phosphoric acid, hydrofluoric acid, hydrobromic acid, hypochlorous acid, silicic acid, nitrous acid, sulfurous acid, carbonic acid, fluorosilicic acid, fluoroboric acid, etc.)

　　(2)Organic acids: (formic acid, acetic acid, propionic acid, butenoic acid, lauric acid, fatty acid, lactic acid, glycolic acid, peracetic acid, oxalic acid, malonic acid, succinic acid, maleic acid, malic acid, tartaric acid, phthalic acid, phenylacetic acid, etc.)

　　(3)Alkalis and hydroxides: (sodium hydroxide, potassium hydroxide, ammonium hydroxide, calcium hydroxide, magnesium hydroxide, barium hydroxide, aluminum hydroxide, iron hydroxide, ammonium sulfate, ammonium nitrate, ammonium carbonate, ammonium nitrate, ammonium phosphate, ammonium persulfate, ammonium chloride, sodium silicate, potassium hypochlorite, aluminum carbonate, aluminum nitrate, aluminum sulfate, potassium acetate, potassium formate, potassium, copper sulfate, copper nitrate, alum, calcium carbonate, etc.)

　　(4)Elements, gases, and other inorganic compounds (sulfur, sulfur colloid, phosphorus, mercury, hydrogen peroxide, ammonia, coal element, carbon monoxide, carbon dioxide, sulfur dioxide, hydrogen chloride, hydrogen bromide, hydrogen sulfide, phosphine, boron fluoride, calcium oxide, zinc oxide)

　　(5) Alcohols, aldehydes, ketones, ethers, esters, hydrocarbons and petroleum products (methanol, ethanol, n-propanol, isopropanol, propanol, butanol, sec-butanol, tert-butanol, ethanol, tert-butanol, formaldehyde, acetaldehyde, butyraldehyde, asphalt, etc.)

　　(6) Other elemental compounds, industrial liquids and products, food and vegetable oils, atmosphere, water, soil (soap, detergents, sulfur lime, bleach, ink, latex, starch, gelatin, animal oil, rosin, nicotine, vinegar, yeast, wine, seawater, brine, ultrapure water, acidic mineral water, wastewater, soil, etc.)

　　(7) Halogenated organic compounds, amines, phenols, other organic compounds (chloropropanol, chloramine, hexachlorobenzene, freon, dimethylformamide, resorcinol, hydroquinone, sodium phenolate, morphine, nicotine, etc.)

　　Specifications

　　Polyethylene plastic storage tanks (tanks) include vertical (flat bottom, cone bottom) and horizontal types; transport tanks include road transport tanks and carriage transport tanks; mixing tanks include flat-lid flat-bottom, flat-lid cone-bottom, and reactor-type tanks; steel-lined plastic storage tanks (tanks) (steel-plastic composite storage tanks (tanks)) include vertical (flat bottom, cone bottom) and horizontal types, and a series of other products. Various storage tanks can also be customized as needed. Generally, the capacity of all-plastic storage tanks ranges from 1 cubic meter to 50 cubic meters. Steel-lined vertical storage tanks and steel-plastic composite vertical storage tanks.Tortoise shell lined tanks have a capacity of 1 to 150 cubic meters.

　　Stainless Steel Type

　　Stainless steel tank

　　Classification

　　1. Classification by form: can be divided into vertical stainless steel tanks and horizontal stainless steel tanks.

　　2. Classification by use: can be divided into stainless steel tanks for brewing, food, pharmaceuticals, dairy, chemicals, petroleum, building materials, electricity, and metallurgy.

　　3. Classification by hygiene standards: hygienic stainless steel tanks and ordinary stainless steel tanks.

　　4. Classification by pressure requirements: stainless steel pressure vessels and non-stainless steel pressure vessels.

　　Common Stainless Steel Tanks

　　Stainless steel tanks, stainless steel pressure tanks, stainless steel wine tanks, stainless steel milk tanks, stainless steel reaction tanks, stainless steel vacuum tanks, stainless steel fermentation tanks, tank structure and performance

　　● Container insulation material uses high-temperature resistant, anti-aging polyurethane foam or pearl cotton.

　　● Interfaces use internationally standardized quick-coupling plates; the inner tank uses imported 316L or 304, with an inner surface mirror polish Ra≤0.28μm, and an outer surface matte, mirror, sandblasted, or cold-rolled original color matte finish.

　　● Ports: include liquid level gauges (digital or glass tube type), air breather, thermometer (digital or dial type), CIP cleaning port, sight glass, explosion-proof sight light, SIP sterilization port, inlet and outlet ports, and manholes, etc.

　　● Capacities range from 500L to 30000L, and can also be designed and manufactured according to customer needs.

　　Stainless Steel Tank Overview:

　　1. Food and Pharmaceutical Stainless Steel Tanks:

　　Stainless steel mixing tanks, stainless steel concentrated tanks, stainless steel diluted tanks, stainless steel extraction tanks, stainless steel reaction tanks, stainless steel storage tanks, stainless steel mixing tanks, stainless steel seed tanks, stainless steel nitric acid tanks, stainless steel glacial acetic acid tanks, stainless steel carbon disulfide tanks, stainless steel water tower tanks.

　　2. Brewing and Dairy Stainless Steel Tanks:

　　Stainless steel wine tanks, stainless steel liquor tanks, stainless steel wine tanks, stainless steel milk tanks, stainless steel beverage tanks

　　3. Chemical Stainless Steel Tanks:

　　Stainless steel oil tanks, stainless steel transport tanks, stainless steel cooling tanks, stainless steel insulated tanks, stainless steel heat exchange tanks, stainless steel buffer tanks, stainless steel outdoor tanks, and various levels of stainless steel pressure vessels in the chemical industry.

　　Features of Stainless Steel Tanks:

　　1. Stainless steel tanks have strong corrosion resistance and are not corroded by external air or residual chlorine in water. Each spherical tank undergoes rigorous pressure testing and inspection before leaving the factory, and its service life under normal pressure can exceed 100 years.

　　2. Stainless steel tanks have good sealing; the sealed design completely prevents harmful substances and insects in the air from entering the tank, ensuring that the water quality is not polluted by the outside world and prevents the breeding of red worms.

　　3. The scientific water flow design prevents the sediment at the bottom of the tank from being stirred up by the water flow, ensuring that the domestic water and fire water are naturally stratified, and the turbidity of the domestic water coming out of the tank is reduced by 48.5%; however, the water pressure is significantly increased. This helps improve the performance of domestic water and fire water facilities.

　　4. Stainless steel tanks do not require frequent cleaning; the sediment in the water can be discharged by periodically opening the drain valve at the bottom of the tank. Every 3 years, simple equipment can be used to remove scale once, greatly reducing cleaning costs and completely avoiding contamination by human bacteria and viruses.