What is a storage tank
What is a storage tank?
Storage tank is used to store liquid or gas steel sealed container that is steel storage tanks, steel storage tank project is petroleum, chemical, grain and oil, food, fire, transportation, metallurgy, national defense and other industries essential, important infrastructure, our economic life is always inseparable from the large and small steel storage tanks, steel storage tanks in the national economic development plays an important role is irreplaceable. With the continuous development of the storage tank industry in front of us, more and more industries and enterprises use storage tanks, more and more enterprises into the storage tank industry, steel storage tanks is the storage of various liquid (or gas) raw materials and finished products of special equipment, for many enterprises without storage tanks can not be normal production, especially the national strategic material reserves are inseparable from the various capacities and types of storage tanks. China’s oil storage facilities are mostly above-ground storage tanks, and the majority of metal structures.
Materials for storage tanks
Tank engineering materials required are divided into tank materials and ancillary facilities materials.
Tank materials can be divided into low tensile yield strength or tensile standard strength steel and high strength steel, stainess steel, high strength steel used for more than 5000m³ tanks; ancillary facilities (including wind-resistant ring beam, locking mouth, pan ladder, guardrail, etc.) are lower strength of ordinary carbon structural steel, the rest of the fittings, accessories are used according to different uses of other materials. Commonly used domestic steel for manufacturing tanks are 20, 20R, 16Mn, 16MnR and Q235 series.
The use of storage tanks
Storage tank is the storage container for long-distance oil and gas pipeline transmission medium. The storage tank at the first station of the pipeline is used for collecting and storing oil and ensuring the stability of the pipeline transmission volume, while the storage tank at the last station is used for receiving and reserving incoming oil and providing it to the oil-using units. The storage tanks at the end gate stations of gas transmission pipelines are mainly used for peaking of city gas and are gradually being replaced by underground gas storage and pipeline gas storage.
Standards of storage tanks
Common storage tank standards
- 1. American Petroleum Institute standard: API650.2;
- 2. British Standard: BS2654.3;
- 3. Japanese standard: JISB8501.4;
- 4. German Standard: DIN4119.5;
- 5. Petroleum industry standard: SYJ1016.6;
- 6. Petrochemical industry standard: SH3046.
The process of storage tank
Production of storage tanks
Suitable for molding large and very large parts
Most of the plastic molding process, in the molding process, the plastic and mold are under a fairly high pressure (pressure), such as injection molding, compression molding, extrusion. Spitting, etc., so the application of these molding processes to produce large plastic parts, not only must use the mold can withstand a lot of pressure, so that the mold becomes bulky and complex, and plastic molding equipment must also be designed and manufactured very strong, the processing and manufacturing difficulties of the mold correspondingly increased, the cost increases. In contrast, anti-corrosion storage tanks due to rotomolding process only requires the strength of the frame is sufficient to support the material, mold and the weight of the frame itself, as well as to prevent material leakage of the closed mold force, so even if rotomolding large and very large plastic parts, anti-corrosion storage tanks, etc. also do not need to use very bulky equipment and molds, the processing and manufacturing of the mold is very convenient, short manufacturing cycle, low cost. Theoretically speaking, with rotomolding Theoretically, there is almost no upper limit on the size of the molded parts. But it is easily limited by production conditions and road transportation. And the production of such large plastic containers, such as the use of spit molding, without very expensive and large blow molding equipment is not possible.
Anti-corrosion storage tanks and other suitable for multi-species
Small batch production of plastic products. Because rotomolding with mold is not subject to external forces, so the mold is simple, inexpensive, easy to manufacture. In addition, rotomolding equipment also has greater mobility, a rotomolding machine, you can install a large mold, can also arrange a number of small chess set; it can not only mold different sizes of parts, but also at the same time molding size and shape are extremely different products, as long as the same raw materials used in rotomolding products, the thickness of the product is equivalent, can be simultaneously rotomolded, so the anti-corrosion storage tank rotomolding process compared to other Therefore, the rotomolding process of anti-corrosion storage tanks has greater flexibility than other molding methods.
Rotomolding is very easy to change the color of the product
Rotational molding each time the material directly into the mold, which makes all the material into the product products from the mold after the product is removed and then add the next molding materials needed, so when we need to change the color of the product, neither waste a drop of raw materials nor time to clean the machine and mold anti-corrosion storage tanks. When we use multiple molds to rotomold the same plastic products, we can also add different colors of materials in different molds and rotomold different colors of plastic products at the same time.
Processing of storage tanks
(1) Processing of polyethylene storage tanks.
Polyethylene (PE) horizontal storage tanks to pure polyethylene (linear low density polyethylene LLDPE, high density polyethylene HDPE) as raw materials, using rotomolding process as a whole once formed.
(2) steel-lined plastic storage tank processing technology.
Steel lined plastic vertical storage tank is also known as turtle lining storage tank (turtle lining – steel, mesh, plastic three in one) is the essence of steel-plastic composite series products. It uses a special rotomolding process. It is the steel mesh (turtle nail) welded to the surface of the steel body, pure polyethylene (linear low density polyethylene LLDPE, high density polyethylene HDPE) as raw materials, the use of rotomolding process will be steel, steel mesh (turtle nail) and polyethylene organic combination into one. The polyethylene is firmly dipped into the surface of the steel body. The product has the advantages of no welded seam, no leakage, no toxicity, anti-aging, impact resistance, corrosion resistance, long life, in line with health standards, etc. It makes up for the poor rigidity and strength of all-plastic rotomolded storage tanks, not pressure-resistant, poor temperature resistance shortcomings.
Features of storage tank
Classification of storage tanks
Due to the different storage media, the form of storage tanks is also varied.
- Classification by location: can be divided into above-ground storage tanks, underground storage tanks, semi-underground storage tanks, offshore storage tanks, submarine storage tanks, etc.
- According to the classification of oil products: can be divided into crude oil storage tanks, fuel oil storage tanks, lubricating oil tanks, edible oil tanks, fire water tanks, etc.
- According to the classification of use: can be divided into production oil tanks, storage oil tanks, etc.
- Classification by form: can be divided into vertical storage tanks, horizontal storage tanks, etc.
- According to the classification of structure: can be divided into fixed-top tanks, floating-top tanks, spherical tanks, etc.
- Classification by size: above 50m3 for large storage tanks, mostly vertical tanks; below 50m3 for small storage tanks, mostly horizontal tanks.
- According to the material of the storage tank: the material required for the tank project is divided into tank materials and ancillary facilities materials. Tank 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 used for more than 5000m3 tanks; ancillary facilities (including wind-resistant ring beam, locking mouth, pan ladder, guardrail, etc.) are lower strength ordinary carbon structural steel, the rest of the fittings, accessories are used according to different uses of other materials, manufacturing tanks commonly used domestic steel 20, 20R, 16Mn, 16MnR, and Q235. 16MnR, and Q235 series, etc.
The structure of the storage tank
China’s most widely used, the most mature production and installation technology is the vaulted storage tanks, floating roof tanks and horizontal storage tanks.
Vaulted storage tank
Vaulted storage tank is a steel container with a dome roof and a cylindrical tank body. Vaulted tanks are simple to manufacture and inexpensive, so they are most widely used in many industries at home and abroad, the most commonly used volume of 1000-10000m3, the maximum volume of domestic vaulted tanks has reached 30000m3.
The bottom of the tank: the bottom of the tank is assembled from steel plates, the steel plate in the middle of the bottom is the middle width plate, the surrounding steel plate is the edge plate. Edge plate can be used strip plate, can also be used bow-shaped plate. In general, the internal diameter of the tank <16.5m, it is appropriate to use strip edge plate, the internal diameter of the tank ≥ 16.5m, it is appropriate to use bow edge plate.
Tank wall: the tank wall is welded by multiple circles of steel plate pairs, divided into sleeve type and linear type.
Sleeve type tank wall plate ring weld using lap joints, longitudinal weld for butt. Vaulted storage tank using the form, the advantage is to facilitate the grouping of each circle wall plate, using the inversion method of construction is safer.
Straight tank wall plate ring weld for butt. The advantage is that the wall as a whole from top to bottom of the same diameter, especially for internal floating roof storage tanks, but the group of installation requirements are higher and more difficult.
Tank top: the top of the tank has a number of sector plate group welded into a dome shape, the inside of the tank top using flat steel made of reinforcement, each sector plate between the lap weld, the entire tank top and the upper part of the wall plate angle ring (or locking mouth) welded into one.
Floating-top storage tank
Floating roof storage tank is composed of floating roof and vertical cylindrical tank wall floating on the surface of the medium. The floating roof rises and falls with the increase or decrease of medium storage in the tank, and there is an annular sealing device between the outer edge of the floating roof and the tank wall, and the medium inside the tank is always directly covered by the inner floating roof to reduce medium volatilization.
The bottom of the tank: the volume of the floating roof tank is generally large, its bottom plate are used bow edge plate.
Tank wall: the use of linear tank wall, butt welding seams should be polished smooth to ensure that the inner surface is smooth. The upper part of the floating roof tank is open, in order to increase the rigidity of the wall plate, according to the size of the wind load in the region, the top of the tank wall needs to be set up to resist wind ring beam and strengthen the ring.
Floating roof: floating roof is divided into single-disk floating roof, double-disk floating roof and float floating roof and other forms.
Single-disk floating roof: a number of independent compartments form a ring-shaped floating vessel, the inner side of its ring is a single-disk top plate. The bottom of the single-disc top plate is reinforced with multiple ring-shaped steel rings. Its advantage is low cost and good maintenance.
Double-disc floating roof: It is composed of upper disc plate, lower disc plate and cabin edge plate, separated by radial partition plate and circular partition plate into several independent annular chambers. Its advantage is that the buoyancy, drainage effect is good.
Internal floating roof storage tank
Inside the floating roof storage tank is in the vaulted tank inside the additional floating roof, the tank can reduce the volatile loss of media, the external vault can prevent rain, snow and dust into the tank, to ensure that the medium inside the tank clean. This kind of storage tank is mainly used for storing light oil, such as gasoline, aviation kerosene, etc. The internal floating roof tank adopts linear wall, butt-welded wall plate, and the vault is made according to the requirements of the vault storage tank. Domestic internal floating roof has two structures: one is the same steel floating roof as the floating roof tank; the other is the aluminum alloy floating roof assembled and formed.
Horizontal storage tank
Horizontal storage tank volume is generally less than 100m3, usually used for production links or gas stations. Horizontal storage tank ring weld using lap joints, longitudinal weld using butt joints. The lap plates are arranged interactively, taking an odd number, so that the end caps have the same diameter. Horizontal storage tank end caps are divided into flat end caps and disc end caps, flat end caps horizontal storage tanks can withstand 40kPa internal pressure, disc end caps horizontal storage tanks can withstand 0.2Mpa internal pressure. Underground horizontal storage tanks must be set up to strengthen the ring, strengthen also made of angle steel simmering.
Design of storage tanks
Hazard analysis of large crude oil storage tank project
Crude oil hazard analysis
Crude oil is a B class flammable liquid with flammability; the explosion limit range is narrow, but the value is low and has a certain explosion risk, while the easy boiling over of crude oil should be given special attention when fighting fire.
Analysis of the causes of fire and explosion accidents
The characteristics of crude oil determine that the fire and explosion hazard is the main and most important risk factor for large crude oil storage tanks. The three necessary conditions for a fire accident to occur are: ignition source, combustible material and air.
The problem of ignition source is mainly solved by strengthening management, while the problem of combustible leaks must be prevented and controlled during the tank design process.
Leaking crude oil is exposed to air, which constitutes combustibles. Crude oil leaks, which occur more frequently in storage and transportation, mainly include runaway oil from bubbling tanks, runaway oil from dewatering, runaway oil from damaged equipment, pipelines and valves, and volatile oil and gas caused by poor sealing, in addition to the possibility of mega-leakage accidents such as open-weld rupture of tank bottoms and sinking of floating pans.
Corrosion is one of the important factors in the occurrence of leaks. At home and abroad, there have been a number of oil leakage accidents caused by the corrosion of the tank bottom. The results of the preliminary investigation of the corrosion of crude oil storage tanks show that the corrosion of the bottom of the tank is serious, mostly ulcer-like pit corrosion, mainly in the welding heat-affected zone, depressions and deformation, the top of the tank corrosion second, accompanied by pore corrosion of the uneven overall corrosion, the tank wall corrosion is lighter, for uniform pitting, mainly at the oil-water interface, oil and air interface. Relatively speaking, the bottom of the tank is more serious external corrosion, mainly occurs on the edge of the plate and ring beam base contact side.
Floating plate sinking accident is one of the serious malignant equipment accidents that are very taboo in the production operation of floating roof tanks. The occurrence of such accidents, on the one hand, reflects the design, construction, management and other aspects of the serious defects, on the other hand, will cause a large number of crude oil leakage, seriously affect the production, pollution of the environment and constitute a fire hazard.
The main safety problems in the design of large crude oil storage tanks and their countermeasures
Storage tank foundation and foundation
Tank engineering foundation survey and tank foundation design is the most fundamental guarantee to ensure the safe operation of large storage tanks. According to the petrochemical industry standards, engineering geological survey must be carried out in the process of site selection, for general foundations, soft ground, mountainous ground and special ground, respectively, to explore the situation, the corresponding foundation treatment methods, and should also be made to evaluate the seismic effects of the site and foundation, to avoid building on soft and hard foundations or active geological fracture zones within the influence of the range.
Common forms of tank foundations are ring wall (beam) type, outer ring wall (beam) type and berm type. Selection should be made according to geological conditions. Tank foundation must have sufficient overall stability, uniformity and sufficient plane bending stiffness, the tank wall directly below the foundation structure stiffness should be strengthened to support the base plate bed should be rich in flexibility to absorb welding deformation, it is appropriate to set up a waterproof oil barrier and oil leakage signal pipe, the distance between the water table and the top surface of the foundation shall not be less than the height of capillary water can reach (generally 2m).
Heating technology of storage tanks
The traditional way of tank heating is this: the use of the tank is installed in the column or coil heater, so that the tank viscous liquid through the exchange of hot media (generally saturated steam as the hot media) to achieve the heating of viscous liquids, reduce the viscosity of the liquid, improve its liquidity, in order to facilitate the pumping.
Traditional storage tank heating method used for many years, can not help but increasingly reveal its drawbacks:.
- 1. Low heat transfer efficiency, high steam consumption. Traditional tank heaters for viscous liquid heating is a static natural convection heat transfer, its exothermic coefficient is extremely low. Due to the low heat transfer efficiency, the high temperature of the condensate, often with a large amount of steam excluded. At the same time, due to the high temperature of the viscous liquid on the surface of the heating tube, the high temperature surface of the heat exchanger tube stays for a long time, it is very easy to produce decomposition, coking on the surface of the heat exchanger tube, easy to coke, seriously impede the transfer of heat, but also affect the efficiency of heat transfer.
- 2. Heating process is not economic. When only a small amount of viscous liquid needs to be poured out, but also to the entire tank of viscous liquid all the heating, heating the number of several times the amount used, so that a large amount of steam to do useless work.
- 3. The temperature of the viscous liquid in each part of the tank is not balanced. The temperature of the viscous liquid near the heater is higher, the temperature of the viscous liquid far from the heater is lower, and the temperature of the extracted viscous liquid is even lower, which seriously affects the liquidity of the oil.
- 4. Affect the quality of viscous liquid. Repeatedly heating the viscous liquid in the tank, the heating process produces a large number of fine decomposition materials, which has a certain impact on the quality of viscous liquid and increases the cost of post-processing.
- In view of the drawbacks of the traditional tank heating method, a new local fast heater technology is generated.
New local fast heater
- 1. The “vortex hot film heat exchanger” along the tank radially into the bottom of the tank, the thermal medium (steam) to take the tube process, viscous liquids from the shell process flow between the de tube, the shell suction port directly connected to the tank medium.
- 2. In the heat exchanger steam inlet set temperature control valve, through the temperature probe to detect the temperature of the viscous liquid outlet to control the steam inlet steam into the heat exchanger, so as to ensure that the viscous liquid temperature is constant.
The heat exchanger adopts high-efficiency heat transfer element – vortex hot film tube, which keeps the viscous liquid flowing reasonably between the tubes, and the thermal efficiency is 3-5 times of the ordinary heat exchanger, and its enhanced heat transfer mechanism is: the viscous liquid fluid is designed to flow turbulently on the inner and outer surfaces, producing strong shock and scouring effect, and the direction of flow is constantly changing, which is close to the The high temperature viscous liquid fluid on the surface of the pipe wall is constantly replaced, the heat insulation layer becomes thinner and even destroyed, the heat transfer from the metal surface is accelerated, the fluid microscopic vortex is strengthened, and the heat diffusion inside the viscous liquid fluid is strengthened. Will not make the fluid close to the surface of the tube wall to produce local high temperature superheat, so the viscous liquid can be both appropriate, full heating and no coking decomposition may. Both good heat transfer, but not a lot of resistance.
- 1. Fast heating speed, high heat transfer efficiency, not easy to scaling.
- 2. It can be heated quantitatively for viscous liquid, how much heating is needed.
- 3. Viscous liquid will not appear local high temperature, charring, to ensure the quality of viscous liquid and heater heat transfer efficiency.
- 4. The highest temperature of the oil outlet in the storage tank ensures the liquidity of the viscous liquid poured out.
- 5. It avoids repeated heating of the viscous liquid in the tank, ensures the color of the viscous liquid and reduces the cost of viscous liquid treatment.
- 6. Long service life, corrosion resistance, high temperature resistance, high pressure resistance, anti-scaling function, greatly improving the overall performance of the heat exchanger.
- 7. Advanced design of the process structure, to ensure the smooth flow of viscous liquid and a better “pumping tank bottom” role.
- 8. Automation control can be realized, according to the inlet and outlet temperature of viscous liquid and pouring oil flow control steam feed amount.
- 9. Compact structure, easy installation and maintenance, will not affect the safety of the tank because of the installation of the heater. Compared with the U-tube heat exchanger, in the same heat transfer area: vortex heat film heat exchanger size, only about one-half the size of the U-tube heat exchanger.
- 10. Compared to the electric heating method, safer, more gentle heating, the impact of viscous liquid quality is smaller.
In the lubricating oil storage tank heating, the local fast heater and the traditional column tube type heating comparison.
The quantity of oil
The steam consumption of
Tubular heat exchanger
0.8Mpa saturated steam
30 ℃ to 60 ℃
14 hours and 30 minutes
Tank local quick heater
0.8Mpa saturated steam
30 ℃ to 60 ℃
One hour and 30 minutes
Note: Data from Sinopec lubricant actual measurement comparison table.
Safe operation of storage tanks
- 1. The operation of this equipment must be strictly and systematically trained and qualified by the examination (written and actual operation) and obtain the equipment operator’s certificate to operate the equipment, any person without training is strictly prohibited to operate the equipment.
- 2. Not familiar with the performance of the equipment is strictly prohibited to operate the equipment, safety protection equipment is not fully worn is strictly prohibited to operate the equipment, not all familiar with and master the equipment operating procedures are strictly prohibited to operate the equipment.
- 3. On-site professional and technical personnel have the right to prevent and correct others from operating in violation of rules and regulations, risky and unsafe behavior; they have the right to refuse the command, dispatch and order that do not meet the safety requirements or violate the rules and regulations.
- 4. All personnel entering the unloading area are forbidden to enter with communication tools! Must be in the electrostatic discharge point for the body electrostatic discharge operation!
- 5. Must check whether the insulating rubber mat in front of each control cabinet is complete and dry before starting work. The equipment must be checked for leakage with an electrometer pen before the equipment is started.
- 6. Equipment in case of emergency should press the red emergency stop switch, and turn off the total power supply of the equipment, immediately notify the equipment maintenance workers to deal with, and notify the relevant management personnel and equipment department personnel, unauthorized handling is strictly prohibited.
- 7. Equipment safety protection device in any case is strictly prohibited for any reason to disassemble, destroy, short or diverted for other uses, so that the safety protection facilities fail.
- 8. It is strictly forbidden to operate the equipment by consuming or drinking drugs or drinks that reduce concentration or trance.
- 9. It is strictly forbidden for the intern to operate the equipment alone without the supervision of the shift manager or master!
- 10. It is strictly forbidden to intervene inside the equipment when the process is immature, unreasonable, or when all or part of the body needs to be in automatic operation of the equipment during operation.
- 11. Plant leaks or water around the equipment is strictly prohibited to work on the machine.
- 12. All kinds of lubricants and liquid media such as spills, must be promptly cleaned and wiped, strictly prohibited in the slippery environment operation.
- 13. It is strictly forbidden to put items into the operating cabinet and operating table to avoid causing short-circuit injury and damage to the equipment.
- 14. The operator must turn off the power supply of the equipment when repairing or cleaning the equipment, and hang the safety warning sign of “Forbidden to close the gate, someone is working”, and must be supervised by a person, forbidden to operate alone! It is strictly forbidden to use chemical fiber materials to wipe and clean the equipment!
- 15. JIT procurement and distribution department procurement manager will issue the notice of incoming materials and unloading in written form one day in advance, HR department will arrange to guard the unloading area, production company will be ready to unload materials, tanker must be equipped with flame arrestor, and it is strictly prohibited to explode in the hot sun! It is strictly forbidden to unload materials in thunderstorm! It is strictly forbidden for the tanker truck to stay at the company gate for more than 60 minutes.
- 16. You should wear anti-static clothing and protective equipment to enter the cyclopentane area, it is strictly forbidden to wear chemical fiber clothing to enter, it is strictly forbidden to take off and change clothes in the cyclopentane area, and it is strictly forbidden to wear shoes with nails.
- 17. It is strictly forbidden to bring beeper, cell phone, flammable and explosive items into the unloading area, and it is strictly forbidden to knock with iron in the cyclopentane area.
- 18. found leakage should immediately clear the surrounding fire sources, as soon as possible to organize the recovery to the container such as fire can be sprayed with water to cool the container, if possible to move the container from the fire to the open, in the fire in the container has been discolored or from the safety relief device to produce sound, must immediately evacuate, fire extinguishing agent can be used sand, dry powder or carbon dioxide, water is not effective.
- 19. Cyclopentane if contaminated clothing, soapy water and water should be used to thoroughly wash the skin.
- If cyclopentane is splashed into the eyes, lift the eyelids, flush with running water or saline, and seek medical attention.
- 21. If you inhale cyclopentane, you should immediately leave the scene to fresh air, keep the airway open, if you have difficulty breathing, you should immediately infuse oxygen, if you stop breathing, you should immediately perform artificial respiration and seek medical attention.
- 22. If you swallow cyclopentane, drink enough warm water, induce vomiting and seek medical attention.
- 23. During holidays and specific periods, there must be someone on duty to prevent accidents.
- 1. Security guards and unloading operators arrive at the site 15 minutes in advance, and security guards are ready to be on guard! The guarded area is 60 meters from the unloading point! Set up special guards at the entrance of each channel, and forbid all vehicles and personnel to pass, and forbid all open fire operations. Operators first record the level data of the tank level indicator! Do all the preparation work before unloading, such as tank pressure discharge, nitrogen preparation, cotton yarn preparation, copper wrench preparation, etc.!
- 2. After receiving the notice of readiness from the unloading operator, the alert security guard will pass the information to the front gate, and the front gate security guard will notify the tanker to enter the park directly to the unloading point.
- 3. The filling work is in charge of professional and technical personnel and unified command, carried out by professionally trained maintenance personnel and operators paired, all staff entering the site tanker drivers and security personnel outside the site, etc. should absolutely obey the command of professional and technical personnel.
- 4. Security command tanker into the unloading platform, parking, flameout!
- 5. Equipped with 6 35KG dry powder fire extinguishers and enough towels. Make good emergency measures for leakage: protective sand, cotton yarn and other materials are prepared.
- 6. Check by professionals that each fire extinguisher is well sealed and the certificate is within the validity period, check that no fires and cigarettes are brought to the filling staff, and that all participants in the filling must wear anti-static clothing and anti-static shoes.
- 7. Before starting the work, the professional technician will tell all the staff participating in the filling about the whole filling workflow and precautions, and make a good division of work. The drainage operator will use a copper wrench to dismantle the feeding seal, and dock the tanker discharge pipe with the tank feeding port firmly to ensure no leakage.
- 8. Connect the grounding wire of the tank area with the grounding device of the tanker correctly and firmly intact! Lead the site with nitrogen hose to the discharge area for backup.
- 9. In case of lightning and other bad weather, discharging is prohibited.
- 1. When instructed, open the tanker valve and start unloading. Prepare portable hand-measured cyclopentane alarm to test and detect leaks throughout the filling process and have a dedicated supervisor to detect leaks and be ready to close the valve and carry out maintenance.
- 2. In the unloading, the leakage operator must not leave the unloading valve and be ready for emergencies, if leakage occurs immediately close the tanker discharge valve!
- 3. Security immediately deal with leaking cyclopentane raw materials, a small amount of leakage: nitrogen gas blowing goods with cotton gauze to absorb dry cake placed in the receiving tray to put the guide ventilation evaporation. A large number of leaks: use special containers to transfer to the prepared empty barrels, and quickly transferred to the designated storage area!
- 4. After 50 minutes of unloading time, the drainage operator keeps an eye on the pressure change of the tanker.
- 5. Close the valve on the tanker when the unloading in the tanker is confirmed to be complete.
- 6. Pay attention to whether the 90% alarm of super high material level in the control cabinet, such as alarm immediately stop unloading.
After the tank material
- 1. When the relative pressure in the tanker drops to zero, keep the air pressure balance and finish unloading. And at the same time record the data of the tank level indicator!
- 2. Dismantle the linkage pipeline between tanker and tank area, and lift the tank area pipeline high, so that the residual cyclopentane in the hose flows into the storage tank, flush the hose and surrounding gas with nitrogen, and close the feeding valve and feeding port on the storage tank.
- 3. Put the discharge pipe and exhaust pipe of the tank back on the bracket and close the valve of the pipe port.
- 4. After flushing the discharge area with nitrogen for several minutes, reset the fire extinguisher and lift the martial law channel in the operation area.
- 1. Smoking, bringing in fire, turning off cell phone, using tools such as copper explosion-proof tools are strictly prohibited in the unloading area during unloading operation.
- 2. In case of thunderstorm, it is forbidden to unload cyclopentane or to operate with exposed cyclopentane.
- 3. When the tanker transporting cyclopentane arrives at the front door, the security guard at the front door will immediately notify the safety manager.
- 1. Check the ruler on time, fix the inspection, and record carefully.
- 2. Oil dehydration, should not leave people to avoid running oil.
- 3. Receive and pay oil, approve the process, prevent the risk of string.
- 4. Switching oil tanks, open first and then close, to prevent holding pressure.
- 5. After clearing the tank, check carefully before putting it into use.
- 6. Field handover, strict and serious, to avoid mistakes.
- 7. Breathing valve, regular inspection, to prevent pumping deflation.
- 8. The temperature of heavy oil should not exceed the standard to prevent sudden boiling.
- 9. When the pipeline is finished, deal with it in time to prevent freezing and condensation.
- 10. New tank put into use, acceptance visa, before the oil (material).
Inspection and maintenance
For the storage of dangerous media, we are more strict for the testing and maintenance of FRP tanks, the implementation of the testing and maintenance standards:
- 1. for the storage of flammable gases, flammable liquids storage tanks, should be equipped with the necessary fire-fighting equipment, smoking in the tank is strictly prohibited, open fire lighting, heating, and its ignition sources into the tank area.
- 2. the storage of flammable, explosive, toxic, corrosive and other media storage tanks, should be strictly enforced by the relevant provisions of the management of dangerous goods.
- 3. tank inspection and repair must be cut off before the power supply of electrical equipment related to the tank, you must handle the equipment handover procedures.
- 4. the internal medium of the storage tank exhausted, should be closed in and out of the valve or add a blind isolation with its connected pipelines and equipment, and has a clear sign of isolation.
- 5. for flammable, corrosive, toxic, or asphyxiating media storage tanks, must be replaced, neutralization, disinfection, cleaning and other treatments, and after the treatment of analysis and testing, the analysis results should meet the relevant norms, standards. With flammable media is strictly prohibited with air replacement.
- 6. the tank operation must be for the tank work permit. For a longer interruption to continue operations, should be reapplied to the tank work permit.
- 7. thirty minutes before entering the tank operation to take a sample analysis, its oxygen content in the 18-23% (volume ratio) between.
- 8. into the tank to clean up toxic, corrosive residues, to wear good personal protective equipment.
- 9. the need to build scaffolding and lifting devices, must be solid and reliable, in the operation is strictly prohibited to throw material tools inside and outside, to ensure safe operation.
- 10. the tank lighting should use a voltage of no more than 24 pay explosion-proof lamps and lanterns.
- 11. the tank needs to start a fire, you must apply for a fire permit.
- 12. tank operations must be set up guardians, and have a reliable contact measures.
- 13. the completion of the maintenance staff and guardians together to check the tank inside and outside, after confirming that there is no doubt, the guardian in the tank work certificate signed before closing the manhole.
- 14. when releasing water after pressure test, it must be connected to the atmosphere to prevent pumping vacuum.
Oil storage tanks and storage tank area storage oil, dangerous, prone to fire and explosion accidents, must be in accordance with the relevant provisions, the establishment of fire prevention, explosion-proof system, frequent fire inspections, strict fire safety management to ensure fire safety.
- (1) oil storage tanks, storage tank area fire and explosion prevention should be in accordance with GB50183, GB50074 regulations. Low-powered air foam fire extinguishing system should be in accordance with the provisions of GB50151.
- (2) storage tank area should be kept clean, fire dikes should be free of hay, no oil, no combustible materials.
- (3) storage tank area drainage system should be set up water seal well; drainage pipe outside the firewall should be set up valve; tank drainage, there should be a person to supervise the timely removal of residual oil in the water seal well.
- (4) the storage tank area should not be installed non-explosion-proof electrical equipment and high-voltage overhead lines.
- (5) storage tank area should be set up in accordance with the provisions of the fire dike, fire dike should be kept intact.
- (6) the top of the storage tank should be free of oil, no water. Oil storage tanks in and out of oil pipelines, valves should take insulation measures.
- (7) the oil storage tank top of the light-transmitting holes, check gauge hole cover, gasket should be kept intact, hole cover should be covered tightly. Oil measuring port should be equipped with non-sparking metal gaskets.
- (8) the storage tank on the breathing valve, hydraulic safety valve base should be equipped with a flame arrestor. Flame arrestor at least once a quarterly inspection.
- (9) oil storage tanks in and out of the oil pipeline should be equipped with tough hose compensator.
- (10) steel storage tanks should be set up with lightning protection and anti-static grounding device, its grounding resistance should not be greater than 10Ω. grounding point along the bottom of the tank side every 30m set at least one, single tank grounding should not be less than two.
- (11) every spring should be a comprehensive check of lightning protection and anti-static grounding device, test grounding resistance value should meet the requirements.
- (12) floating roof tank between the floating ship and the tank wall should be two cross-sectional area of not less than 25mm2 soft copper wire connection.
- (13) the oil storage tank should be filled with oil to operate within the safe tank level.
- (14) when the condensate oil level is higher than the heating coil, should first be heated with steam riser, to be melted condensate, then use the steam coil heating.
- (15) should not wear chemical fiber clothing and shoes with iron nails on the tank. In the top of the tank should not turn on and off non-explosion-proof torch.
- (16) oil pipeline fires within the storage tank, tank cleaning operations should be implemented industry regulations.
- (17) oil storage tank fire, should immediately report and stop all operations of the tank on fire. Organize fire fighting and start the emergency plan at the appropriate time.
Maintenance and repair
To ensure the safe production of enterprises, equipment safety operation, improve the service life of equipment and labor productivity, the operation of machinery and equipment must be regularly inspected and maintained to prevent mechanical failure and affect production, or mechanical accidents resulting in casualties, the actual production, safety operating procedures and safety overhaul management system, after studying the development of this tank annual tank maintenance overhaul.
Tank maintenance cycle is generally: 60-120 days for medium and 12 months for major repairs. Medium repair: eliminate running, bubbling, dripping, leaking.
Clean or replace the liquid level meter repair or replace the inlet and outlet and drain valve unclogging and cleaning the cooling water coil. Check and repair the safety valve venting flame arrestor. Repair the anti-corrosion layer and insulation layer. Overhaul: including medium repair project repair tank parts, found to have cracks, serious corrosion and other parts, the corresponding repair or replacement of the cylinder section. Repair can be used to repair polymer composite materials. According to the internal and external inspection requirements, as well as after repair or replacement of the cylinder section, the need for leak testing or hydraulic test. Comprehensive embroidery removal and insulation. Treatment of other problems found in the internal and external inspection of the tank.
Inspection methods and quality standards tank repair, such as openings, welding, replacement of the cylinder section, etc., should be based on the “capacity” and other relevant standards, specifications to develop a specific construction program and approved by the unit responsible for technology. Repair materials used (base material, welding rod, welding wire, flux, etc.) and valves, should have a quality certificate, the use of old materials valves, fasteners, must be inspected and qualified before use. Assembly tank fasteners should be coated with lubricating materials, tight bolts should be tightened diagonally in turn. Non-metallic gaskets shall not be reused in general, and the corrosiveness of the medium shall be considered when choosing gaskets. After repair and inspection of qualified before anti-corrosion insulation work. The repair method and quality standard of in-service storage tank with unqualified defects.
- 1. Polishing method to eliminate defects
- 2. Replacement welding or patching
- 3. Replacement of cylinder section
- 4. Digging and patching
- 5. Quick plugging
This kind of problem can not be solved by traditional welding on site and is more dangerous, and the use of replacement media and then welding will cause huge losses in downtime due to long working period and high labor intensity of workers. American Megawatt technology for different equipment, different operating conditions, different forms of corrosion and leakage, using the corresponding technical products, can be fast, simple, effective protection of equipment, especially because of the polymer composite materials have a comprehensive performance of chemical resistance, bonding performance, etc., to avoid the adverse effects of traditional repair welding, so that the life of the repaired equipment even more than the new equipment, from the fundamental solution Corrosion leakage causes, help enterprises to improve equipment management, reduce repair and maintenance costs, and improve the competitiveness of enterprises.
Model of storage tank
FRP storage tank has the following characteristics.
(1) Light weight and high strength, relative density between 1.5-2.0, only 1/4-1/5 of carbon steel, yet tensile strength is close to, or even exceeds, carbon steel, while specific strength can be compared with advanced alloy steel. Therefore, it has excellent performance in aviation, rocket, spacecraft, high-pressure vessels and other applications that need to reduce self-weight. Some epoxy FRPs can reach tensile, flexural and compressive strengths of 400Mpa or more. The density, strength and specific strength of some materials are shown in Table 1-1.
(2) Good corrosion resistance
FRP is a good corrosion resistant material and has good resistance to atmosphere, water and general concentration of acid, alkali, salt and many kinds of oil and solvent. It has been applied to all aspects of chemical corrosion resistance and is replacing carbon steel, stainless steel, wood, non-ferrous metals, etc.
(3) Good electrical properties
Is an excellent insulating material, used to manufacture insulators. Good dielectric properties can still be protected under high frequency. Good microwave permeability, has been widely used in radar radome.
(4) Good thermal performance
FRP thermal conductivity is low, 1.25-1.67kJ/(m-h-K) at room temperature, only 1/100-1/1000 of metal, is an excellent thermal insulation material. In the case of transient ultra-high temperature, it is an ideal material for thermal protection and ablation resistance, and can protect the spacecraft to withstand the high speed airflow above 2000℃.
(5) Good designability
- ① It is possible to design various structural products flexibly to meet the usage requirements according to the needs, and it can make the products have good integrity.
- ② Can fully select the material to meet the performance of the product, such as: can be designed to resist corrosion, instantaneous high temperature, products with special high strength in a certain direction, good dielectric properties, and so on.
(6) Excellent processability
- ① The molding process can be flexibly selected according to the shape, technical requirements, usage and quantity of the product.
- ② The process is simple and can be formed in one time, with outstanding economic effect, especially for products with complex shapes and small quantities that are not easily formed, which highlights its superiority in process.
Polyethylene is abbreviated as PE in foreign language. the highest application temperature is 60℃ for low density polyethylene and 70℃ for high density polyethylene. The lowest application temperature is -70℃. It has the advantages of no welded seam, no leakage, no toxicity, anti-aging, impact resistance, corrosion resistance, long life, and meets sanitary standards. It makes up for the shortcomings of poor rigidity strength of all-plastic rotomolded storage tank, not pressure resistance and poor temperature resistance. The product lining surface is flat, smooth and solid, compared with traditional steel-lined plastic sheet tanks, steel-lined rubber tanks and steel-lined glass fiber reinforced plastic tanks, it has the advantages of better corrosion resistance, no leakage, no peeling, wear resistance, resistance to certain pressure, resistance to higher temperature, longer life, etc. Its price is lower than the traditional tanks of the same specification, and it is an ideal container for storing corrosive liquids. Therefore, it is an extremely excellent corrosion-resistant storage tank. Steel-lined vertical storage tank also has the characteristics of easy installation, small footprint, and can be made into the shape required by the user. Large steel-lined tanks are more prominent in their integrity, which is not achieved by other tank manufacturing processes.
Can store substances
- (1) Inorganic acid: (sulfuric acid, 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, benzodiac acid, phenylacetic acid. (etc.)
- (3) Bases and hydroxides: (sodium hydroxide, potassium hydroxide, ammonia 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 colloids, 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, dilute propanol, butanol, sec-butanol, tert-butanol, n-ethanol, tert-ethanol, formaldehyde, acetaldehyde, butyraldehyde, asphalt. etc.)
- (6) Other elemental compounds, industrial liquids and products, food and vegetable oils, atmosphere, water, soil (soap, detergent, sulfur lime, bleaching solution, ink, latex, starch, gelatin, animal oil, rosin, nicotine, vinegar, yeast, wine, seawater, salt water, high purity water, acidic mineral water, sewage, soil. (etc.)
- (7) Organic compounds containing halogens, amines, phenols, other organic compounds (chloropropanol, chloramine, hexachlorobenzene, Freon, dimethyl formamide, resorcinol, hydroquinone, hydroquinone, sodium phenol, morin, nicotine. etc.)
Among them, polyethylene all-plastic storage tanks (tanks) have vertical (flat bottom, cone bottom), horizontal; transport tanks have car transport tanker, carriage transport tank; mixing tank has a flat cover flat bottom, flat cover cone bottom, reaction tank type, steel-lined plastic storage tanks (tanks) (steel-plastic composite storage tanks (tanks)) have vertical (flat bottom, cone bottom), horizontal and other iterative products, all kinds of tanks can also be customized according to the needs of their own. The general size of all-plastic storage tank is 1 cubic meter to 50 cubic meters. Steel-lined vertical storage tank steel-plastic composite vertical storage tank tortoise-lined storage tank specifications for 1 cubic meters to 150 cubic meters.
Stainless steel type
Stainless steel storage tank.
- 1. According to the form of classification: can be divided into vertical stainless steel tanks, horizontal stainless steel tanks.
- 2. According to the classification of use: can be divided into brewing stainless steel tanks, food stainless steel tanks, pharmaceutical stainless steel tanks, dairy stainless steel tanks, chemical stainless steel tanks, petroleum stainless steel tanks, building materials stainless steel tanks, electric power stainless steel tanks, metallurgical stainless steel tanks.
- 3. According to the classification of health standards: sanitary stainless steel tank, ordinary stainless steel tank.
- 4. According to the pressure requirements classification: stainless steel pressure vessel, non-stainless steel pressure vessel.
Common stainless steel storage tanks
Stainless steel storage tank, stainless steel pressure tank, stainless steel wine tank, stainless steel milk tank, stainless steel reaction tank, stainless steel vacuum tank, stainless steel fermentation tank storage tank structure and performance
The container insulation material adopts high temperature resistant, anti-aging polyurethane foam or pearl cotton.
Interface using the international standard quick-fit chuck type, the inner liner selection of imported 316L or 304, the inner surface mirror polishing Ra ≤ 0.28μm, the outer surface matte, mirror, sandblasted or cold-rolled original color matte.
Pipe port: there are liquid level meter (digital display or glass tube type), air breathing port, thermometer (digital display or dial type), CIP cleaning port, sight glass, explosion-proof sight light, SIP sterilization port, inlet and outlet port and manhole, etc.
The volume includes 500L-30000L, etc., and can also be designed and manufactured according to the actual needs of customers.
Stainless steel storage tank general overview
1. Food and pharmaceutical stainless steel storage tanks.
Stainless steel batching tanks, stainless steel thick with tanks, stainless steel dilute with tanks, stainless steel extraction tanks, stainless steel reaction tanks, stainless steel liquid storage tanks, stainless steel mixing tanks, stainless steel seed storage tanks, stainless steel nitric acid storage tanks, stainless steel glacial acetic acid storage tanks, stainless steel carbon disulfide barrel tanks, stainless steel water tower storage tanks.
2. Stainless steel tanks for brewing and dairy industry.
Stainless steel wine storage tanks, stainless steel white wine storage tanks, stainless steel wine storage tanks, stainless steel milk (milk) tanks, stainless steel beverage storage tanks
3. Chemical stainless steel tanks.
Stainless steel oil storage tanks, stainless steel transport storage tanks, stainless steel cooling storage tanks, stainless steel insulation storage tanks, stainless steel heat exchange storage tanks, stainless steel buffer tanks, stainless steel outdoor storage tanks and stainless steel pressure vessels at all levels of the chemical industry.
Features of stainless steel storage tanks
1. Stainless steel tank has strong corrosion resistance, it is not subject to external air and residual chlorine in water corrosion. Each spherical tank is subjected to superb pressure testing and inspection before leaving the factory, and the service life can be more than 100 years under normal pressure.
2. Stainless steel tank sealing; sealed design completely eliminates harmful substances in airborne dust and mosquitoes invade the tank to ensure that the water is not polluted by the outside world and breeding red insects.
3. The scientific water flow design makes the sediment at the bottom of the tank not turn up due to the water flow, ensuring the natural stratification of water for living and fire fighting, and the turbidity of water for living from the tank is reduced by 48.5%; however, the water pressure increases significantly. It is conducive to improving the performance of domestic water and fire fighting water facilities.
4. Stainless steel tanks do not need frequent cleaning; the precipitated material in the water can be discharged by regularly opening the drain valve at the bottom of the tank. Every 3 years, simple equipment can be used to remove the scale once, greatly reducing the cost of cleaning and completely avoid human bacteria and virus contamination.
PP type vertical storage tank
Equipment use characteristics
I. Working pressure: atmospheric pressure.
The working temperature: PP -10 ℃ – 120 ℃, PVC -40 ℃ – 60 ℃.
2. PP horizontal storage tank: equipment use characteristics.
I. Working pressure: atmospheric pressure.
Working temperature: PP-10℃～120℃, PVC-40℃～60℃.
Accessories for storage tanks
1. Tank attachment is an important part of the tank itself. Its setting can be divided into 4 types according to its role.
- Ensure the completion of oil receiving and sending, storage operations, to facilitate production and operation management.
- To ensure the safety of tank use, to prevent and eliminate all types of tank accidents.
- Beneficial to oil tank cleaning and maintenance.
- Can reduce oil evaporation loss.
2. Pan ladder (or straight ladder): with resting platform, width 650mm, counterclockwise rotation. The top of the tank is equipped with non-slip treads.
The ladder is designed for operators to check the scale on the tank, temperature measurement, sampling, inspection and set up. It has two types of straight and rotating ladders. Generally speaking, small tanks with straight ladders, large tanks with rotary ladders. Guardrail: the height is 800-1000mm.
3. Catwalk: used to connect between tanks, width 650mm.
4. Manhole: there are three common specifications: DN500, DN600 and DN750.
Manhole is for cleaning and maintenance of the tank, the operator to enter and exit the tank and set. General vertical tanks, manholes are installed in the tank wall on the lowermost ring plate, and and the top of the tank above the light hole opposite. The diameter of the manhole is 600 mm, the center of the hole from the bottom of the tank is 750 mm. usually below 3,000 cubic meters of tanks set up a manhole, 3,000 – 5,000 cubic meters set up 1 – 2 manholes, more than 5,000 cubic meters of tanks must be set up two manholes.
5. Light-transmitting hole: common specifications: DN500. Light-transmitting hole, also known as light hole, is for tank cleaning or maintenance of light and ventilation set. It is usually set on the top of the tank above the inlet and outlet pipes, the diameter is generally 500mm, the outer edge from the tank wall 800 – 1000mm, set the number of the same as the manhole.
6. Cleaning hole or drainage hole: drainage hole for light oil, cleaning hole for heavy oil. There are DN50, DN80 and DN100 models.
7. Oil measuring hole: common specification: DN150, which is installed near the top platform of the tank for measuring scale, temperature measurement and sampling. Only one oil measuring hole is installed in each tank, its diameter is 150mm, and the distance from the tank wall is more than 1m.
8. Drainage pipe and automatic water cutter: dewatering pipe is also known as drainage pipe, which is specially designed to remove water and remove oil residue from the bottom of the tank. The release pipe is equipped with a valve on the outside side of the tank, in order to prevent the dewatering valve is not strict or damaged, usually installed two valves. Winter should also do a good job of dehydration valve insulation, to prevent freezing or valve freezing.
9. Inlet and outlet joint pipe.
10. Fire fighting foam room: Fire fighting foam room, also called foam generator, is a fire fighting device fixed on the tank. One end of the foam generator is connected to the foam line, and one end has a flange welded to the uppermost ring plate of the tank wall. The fire extinguishing foam flows through the air suction inlet of the fire fighting foam chamber, draws in a large amount of air to form foam and breaks through the isolation glass into the tank (the thickness of the glass is not more than 2mm), so as to achieve the purpose of coming to the fire.
11. Grounding wire: grounding wire is a device to eliminate static electricity in the tank.
12. Light oil special accessories light oil (including gasoline, kerosene, diesel, etc.) is a small viscosity, light quality, volatile oil, the tank containing such oil, are equipped with their characteristics and meet the production and safety needs of a variety of tank special accessories.
- Tank breathing valve: tank breathing valve is an important equipment to ensure the safe use of oil tanks and reduce oil loss.
- Hydraulic safety valve: hydraulic safety valve is another important equipment to improve the performance of the tank for greater safety use, its working pressure is 5 – 10% higher than the mechanical call valve. Under normal circumstances, it is not moving, when the mechanical breathing valve failure due to valve disc rust or jamming or tank collection and payment operations are abnormal and the tank overpressure or vacuum is too large, it will play the role of tank safety seal and prevent tank damage.
- Flame arrestor: flame arrestor, also known as tank fire protection, is the fire safety facilities of the tank, it is installed in the mechanical breathing valve or hydraulic safety valve below, the interior is equipped with many copper, aluminum or other high heat capacity metal made of wire mesh or wrinkled plate. When foreign flames or sparks in case through the breathing valve into the fire arrester, metal mesh or wrinkled plate can quickly absorb the heat of burning material, so that the flame or spark extinguished, thus preventing the tank from catching fire.
- Spray cooling device: Spray cooling device is an energy-saving facility installed to reduce the oil temperature in the tank and reduce the size of the tank breathing loss.
Internal floating roof tank special accessories Compared with the general vaulted roof tank, the internal floating roof tank is equipped with various unique special accessories due to its different structure and according to its usage performance requirements.
Ventilation hole: Inner floating roof tank because the inner floating disk covers the oil surface, the oil and gas space is basically eliminated, so evaporation loss is very little, so the top of the tank is not equipped with mechanical breathing valve and safety valve. However, in practice, the floating roof ring gap or other accessories joint part, there is still inevitably oil and gas leakage, in order to prevent the accumulation of oil and gas to a dangerous level, in the tank top and tank wall are opened with ventilation holes.
Electrostatic export device: floating roof tank in the process of oil in and out of the operation, the floating disk has accumulated a large amount of electrostatic charge, due to the floating disk and the tank wall with more insulators for sealing materials, so the floating disk on the accumulation of electrostatic charge is not possible through the tank wall to guide away. In order to guide away this part of the electrostatic charge, between the floating disk and the top of the tank installed electrostatic export line. Generally for 2. Soft copper bare stranded wire, the upper end and light hole connected, the lower end pressed in the floating plate cover pressure bar.
- Anti-rotation steel rope: In order to prevent the deformation of the tank wall, the floating disk rotation affects the smooth lifting, the internal floating roof tank between the top and bottom of the tank vertically tensioned two stainless steel cables, two steel ropes in the floating roof diameter at both ends of the symmetrical arrangement. Floating top in the steel rope restrictions, only vertical lift, thus preventing the floating disk rotation.
- Automatic venting valve: The automatic venting valve is located in the middle of the floating disk, it is to protect the floating disk in the support position, the tank can breathe normally when entering and leaving the oil, and prevent the following part of the floating disk from evacuating or holding pressure.
- Floating plate pillar: floating roof tank after a period of time, the floating roof needs to be serviced, the tank needs to be cleaned, then the floating roof needs to be lowered to a certain height from the bottom of the tank, supported by a number of pillars on the floating plate.
- Diffusion tube: diffusion tube in the tank and the inlet pipe, the diameter of the pipe for the inlet pipe twice, and on both sides evenly drilled with numerous small holes of 2mm diameter. It plays the role of reducing the flow rate and protecting the pillar of the float when the tank receives oil.
Crude oil storage and loading process discharge
Mainly includes: storage tank large and small breathing loss, oil running and dripping and loading loss.
1. large breathing loss of storage tanks Large breathing refers to the breathing of oil when the tank is fed with oil. When the oil tank is fed, as the oil surface gradually rises, the gas space gradually decreases and the pressure inside the tank increases. When the pressure exceeds the control pressure of the breathing valve, the oil vapor of a certain concentration starts to exhale from the breathing valve until the tank stops collecting oil, and the exhaled oil vapor causes the loss of oil evaporation. When the oil tank sends oil outward, the gas space gradually decreases due to the oil surface continuously decreasing, the pressure inside the tank decreases, when the pressure is less than the breathing valve control vacuum, the tank starts to inhale fresh air, as the oil surface above the space oil gas does not reach saturation, prompting the oil evaporation to accelerate, so that it regains saturation, the pressure inside the tank rises again, causing part of the oil vapor to be exhaled from the breathing valve. The main factors affecting the big breathing are.
The nature of oil products. The lower the density of the oil, the more light fractions, the greater the loss.
Receiving and sending oil speed. The faster the speed of incoming and outgoing oil, the greater the loss; 1.3 Tank pressure resistance level. The better the pressure resistance of the oil tank, the smaller the breathing loss. When the tank pressure resistance reaches 5kPa, then the reduction rate is 25.1%. If the pressure resistance is increased to 26kPa, then the small breathing loss can be basically eliminated and the large breathing loss can be reduced to some extent.
Related to the geographical location of the tank, atmospheric temperature, wind direction, wind and management level. Measures taken: The oil stored in this project is crude oil, which is less volatile than gasoline and diesel oil, and the pipelines of each storage tank are interconnected, while the internal floating roof tank is used, so the amount of large breathing loss of crude oil is less. 2.
2. Small breathing loss of storage tanks In the absence of oil receiving and dispensing operations, the temperature of the gas space inside the tank, the evaporation rate of oil products, the concentration of oil and gas and the vapor pressure also change as the external temperature and pressure rise and fall in a day. This discharge of oil vapor and inhalation of air caused by the process of oil and gas loss, called small breathing loss. The main factors affecting the small breathing loss are as follows.
Diurnal temperature change. The greater the temperature difference between day and night, the greater the small respiratory loss.
The tank is located in the area of sunlight intensity. The greater the intensity of insolation, the greater the small respiratory loss.
The larger the tank, the larger the cross-sectional area, the greater the small respiratory loss.
Atmospheric pressure. The lower the atmospheric pressure, the greater the small breathing loss.
The extent to which the tank is filled. The tank is full, the gas space volume is small, the small breathing loss is small. Measures taken: The oil stored in this project is crude oil, and the pipelines of each storage tank are interconnected, while the internal floating roof tank is used, and cooling water will be sprayed regularly in summer to prevent small breathing, so the amount of small breathing loss of crude oil is small.
The loss is caused by the storage tank accessories not being tight. Measures taken: strengthen the maintenance of tank accessories, keep the tightness of the tank, and improve the operation management of the tank as the cheapest and very effective measures to reduce losses and prevent pollution. For fire stopper, liquid seal oil, mechanical breathing valve flap, fire foam glass chamber, oil measuring hole, check thoroughly twice a year to make the gas tightness meet the requirements. Make the oil tank as full as possible to the allowed degree, the lower the degree of filling, the greater the loss.
Crude oil loading loss
The loss of crude oil loading mainly refers to the loss generated by the process of loading crude oil to the car tanker. 50% of the crude oil is transported by pipeline out to the ship and 50% is transported by car. The loading is balance loading with gas return system, so the loss is very small. The loading is submerged loading. Measures taken: Crane tube loading and submerged loading are used.
Source: China Tube Sheet Manufacturer – Yaang Pipe Industry (www.steeljrv.com)
(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)
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