Could someone explain the steps and methods for emptying a tank?

1. Pour the remaining oil in the tank into a similar tank or another tank. 2. Open the light-transmitting holes, manholes, and drain holes. 3. Notify the relevant departments to conduct a gas analysis; entry into the tank is permitted only if the hydrocarbon content is below 1% and the oxygen content is above 20%. 4. Introduce steam into the tank as required; be careful to avoid injury from the steam, and use a high-pressure water gun to flush the emulsion into the drainage system after it is introduced into the tank. 5. Check the sealed state of the tank and keep records

Tank cleaning: 1. Cleaning is divided into two types: regular cleaning and irregular cleaning. (1) The purpose of regular cleaning is to ensure product quality, to conduct periodic inspections and maintenance of the internal facilities of the tank, and to create the conditions necessary for re-establishing the volume measurement charts for the tank. (2) Purpose of irregular cleaning: For the renewal or renovation of oil tanks, or for emergency repairs that require the use of fire. 2. Cleaning cycle: Generally, the cleaning cycle for oil tanks is determined primarily by the properties of the oil, the size of the tank, and how frequently the tank is used. Light oil tanks: cleaned once a year. Heavy oil tanks: cleaned once every two years. Crude oil tanks: cleaned once a year. LPG tanks: cleaned once every five years. Lubricant oil tanks: cleaned once every three years. 3. Cleaning methods and steps: (1) First, transfer the remaining oil in the tank to other similar tanks in order to reduce losses due to oil removal from the tank. (2) The inlet and outlet valves as well as the heating valve of the oil tank should be closed tightly, and the handwheels should be tied up with wire; if the valves are not airtight, blind flanges should be installed. (3) After approval, open the sewage discharge hole. At the entrance to this hole (where people are not allowed to enter the tank), use a high-pressure water gun to flush the emulsions and impurities inside the tank into the sewer. The sewer should be equipped with metal screens to prevent rust and other debris from clogging it. Meanwhile, contact the wastewater treatment facility to ensure proper adjustment of the water level and dosage of chemicals used. (4) Heavy oil tanks can be cleaned with high-pressure hot water or by manual excavation; iron tools must not be used to avoid sparking from collisions. (5) When steaming the tank, steam is introduced from the manhole at the lower part of the oil tank or from other locations; the manhole must be tightly sealed with materials such as straw*, and the light inlet at the top should be opened. Steaming time: 48 hours for gasoline and crude oil; 24–36 hours for diesel and kerosene; 24 hours for heavy oil; 24–36 hours for lubricating oil. (6) After steaming, the tank must be inspected by a safety officer, samples taken for analysis, and it must be confirmed that the concentration of oil and gas inside the tank is below the specified limits and harmless to human health before cleaning and wiping the tank can proceed. Ventilation with a fan can be used if necessary during operations inside the tank. (7) After cleaning, it should be inspected and approved by the quality control department; once approved, the containers should be sealed promptly. (8) After sealing the tank, remove the wire from the handwheel as well as the valve blind plate, reconnect the pipelines that were temporarily disconnected, cover the light access holes, close the water cut-off valve, and get ready for oil collection. (9) Organize the tools, clean up debris and maintain hygiene at the site; rust should be buried 0.5 meters underground to prevent it from catching fire due to exposure to sunlight.

First, transfer the remaining oil in the tank to other similar oil tanks in order to reduce losses resulting from emptying the tank. During the maintenance of the oil tank, an oil extraction pipeline can be added to remove all the oil completely.

Other solvent and similar storage tanks can also be cleaned in this way, right! ! !

There are 4 methods for cleaning oil tanks in oil depots, namely dry cleaning, wet cleaning, steam cleaning, and chemical cleaning. 2.1 Safety requirements and procedures for dry cleaning method 2.1.1 Remove oil from the tank, 2.1.2 Ventilate the tank to remove oil vapors and measure their concentration to ensure it remains within safe limits ； 2.1.3 Personnel enter the tank to clean oil, water, and other sediments ； 2.1.4 Dry clean the sawdust. 2.1.5 Remove the sawdust and use copper tools to eliminate local rust. 2.1.6 Thoroughly wipe clean with a mop. 2.1.7 Conduct quality inspection and acceptance for dry cleaning. 2.2 Safety requirements and procedures for the wet washing method 2.2.1 Removing oil from the tank ； 2.2.2 Ventilate to remove oil and gas from the tank, and measure the oil and gas concentration to ensure it is within a safe range ； 2.2.3 Personnel enter the tank to clean oil, water, and other deposits; 2.2.4 Use high-pressure water at 290–490 kPa to wash away oil and scale inside the tank; 2.2.5 Remove the wastewater resulting from washing as soon as possible and wipe the area clean with a mop; 2.2.6 Blow in dry air to remove moisture; 2.2.7 Use copper tools to eliminate localized rust; 2.2.8 Conduct a quality inspection after wet cleaning. 2.3 Safety requirements and procedures for steam cleaning 2.3.1 Draining the oil in the tank ； 2.3.2 Ventilate the tank to remove oil and gas, and determine that the concentration is within a safe range; 2.3.3 Allow personnel to enter the tank to clean away oil, water, and other sediments; 2.3.4 Clean using steam, a method primarily used for cleaning tanks containing viscous oil ； 2.3.5 Flush oil stains with high-pressure water, 2.3.6 Drain the wastewater ； 2.3.7 Dry cleaning with sawdust ； 2.3.8 Remove sawdust and use copper tools to eliminate local rust; 2.3.9 Thoroughly clean off dirt with a mop ； 2.3.10 Check and accept the quality of tank cleaning. 2.4 Safety requirements and procedures for chemical cleaning 2.4.1 Removing oil from the tank ； 2.4.2 Ventilate to remove oil and gas from the tank, and measure their concentration to ensure it is within safe limits ； 2.4.3 Personnel enter the tank to clean oil, water, and other sediments; 2.4.4 Use a tank cleaner to rinse the system and equipment; 2.4.5 Perform acid cleaning for rust removal for 90–120 minutes; 2.4.6 Drain the acid, then rinse with clean water for about 20 minutes, until the rinse water is neutral ； 2.4.7 Drain the wastewater and perform 2 passivation treatments. The first treatment takes about 3 minutes, and the second one takes about 8 minutes ； 2..4.8 5–10 minutes after passivation, rinse again with water at a pressure of 290 kPa for 8–12 minutes ； 2.4.9 Remove the rinse water and wipe clean with a mop ； 2.4.10 Ventilation and Drying ； 2.4.11 Inspect and accept the quality of chemical tank cleaning. 3 Safety Precautions Oil tank cleaning is a relatively dangerous task carried out inside tanks, as oil vapors are not only flammable and explosive but also toxic. Therefore, when washing the tank, the following safety regulations must be strictly followed. 3.1 Open the manhole and inspect the quality of the oil at the bottom of the tank layer by layer to determine the plan for removing and handling the stored oil. 3.2 Personnel entering the tank must wear work clothes, work shoes, work gloves, and a gas mask. Signal ropes and safety belts must also be brought along; a dedicated person should monitor outside the tank. The time spent inside the tank should not be too long – 15 to 20 minutes is generally appropriate – and shifts should be used for work. Additionally, medical staff should be on duty on site. 3.3 For cleaning residual oil and wastewater, brooms or wooden tools should be used; the use of iron or steel tools is strictly prohibited. 3.4 Effective ventilation must be employed. 3.5 Steam method — First, seal all the lids in the tank; once the temperature reaches 60–70°C, open the lids and continue steaming to dissolve all the residual oil in the tank. In short, the use of oil tanks is becoming increasingly common, and accordingly, there are more and more safety issues associated with them. As long as we follow the procedural requirements and adhere to strict operating procedures, we can minimize the risks associated with cleaning the oil tanks and carrying out related operations, thereby enabling oil to serve human production and daily life more effectively.

Safety Technical Regulations for Tank Cleaning (Trial) Chapter 1 General Provisions Article 1 These regulations are formulated in accordance with the principle of \"prevention first\" in order to ensure the proper conduct of tank cleaning tasks, safeguard the safety and health of those who carry out these tasks, improve the technical standards for tank cleaning, and prevent various types of accidents. Article 2 Oil tanks are cleaned under the following circumstances: — The cleaning cycle for oil tanks is generally three to five years. Second, the oil tank should be cleaned when it is converted to store another type of oil product. Third, when the oil tank leaks or is otherwise damaged and requires emptying for inspection or repair involving open flames. Article 3 These regulations apply to the cleaning of oil tanks in petroleum depots at all levels. Gas stations and other petroleum businesses can also follow this practice. Article 4: Take adequate safety measures and ensure the proper inspection and preparation of materials, tools, and equipment. Chapter 2 General Safety Provisions Article 5 The tank cleaning department shall formulate specific and practical tank cleaning plans and safety measures based on the different conditions at the work site. Article 6: The tank cleaning supervisor must be present at the site during the tank cleaning operation to promptly address and resolve any issues that arise. Article 7: The plan for tank cleaning and the safety measures shall be implemented after discussion and approval by the managing manager. Article 8: Before carrying out tank cleaning operations, relevant personnel shall receive pre-job training on safety and related operational techniques in accordance with the assigned roles, and only after passing the assessment may they be allowed to take up their duties. Article 9: Whenever workers enter the tank for inspection or work, a dedicated supervisor must be assigned outside the tank’s manhole, and one supervisor shall not supervise two work sites at the same time. Article 10: Safety (supervision) officers shall strengthen safety inspections at the site, and have the authority to stop any illegal instructions or operations, as well as to report such incidents to the relevant supervisors promptly. Article 11: The team (group) leader and the safety (supervision) officer shall carry out tasks such as on-site safety inspections during shift handovers, as well as counting the personnel and their tools and equipment. Article 12: The workplace shall establish safe distances, set up safety markers or fences, and assign dedicated personnel to oversee these safety markers or fences. Article 13: To ensure safety, a permit system for entering the tank must be implemented for tank entry operations. Article 14: To prevent poisoning of personnel carrying out tank cleaning operations, the following must be ensured: — When the concentration of oil and gas is between 4% and 40% of the explosive lower limit for that type of oil, personnel entering the tank must wear isolated gas masks. II. When the oil and gas concentration exceeds 1% of the lower explosive limit of that oil product and is below 4%, it is permitted for operators to enter the tank for short periods of time without wearing respiratory equipment, provided that they wear gas masks and that each session of work does not exceed 15 minutes ； At the same time, work may be repeated up to four times per working day, with an interval of no less than 1 hour between repetitions. At this concentration, filter-type breathing apparatus (such as gas-filtering masks) can also be used, but the oxygen content in the gas space should not be lower than 18%. III. When the oil and gas concentration is below 1% of the explosive lower limit of that oil, operation for eight hours without protective measures is permitted. Article 15: The air supply for isolated breathing apparatus can be achieved through various methods depending on the conditions, such as self-priming air intake, manual air supply, electric fan-driven air supply, compressor-driven air supply, or use of air compressed internally. Article 16: Depending on the location, the specifications and dimensions of the gas protection equipment and protective gear chosen must ensure proper fitting and good performance; it is essential to strictly follow all the instructions outlined in the \"product manual\" when using them. The inner and outer surfaces of the breathing hose should not be contaminated by oils or similar substances. Article 17: Gas protection equipment, protective gear, and tank cleaning tools must be thoroughly cleaned after each use. Gas protection equipment and protective gear should be carefully tested and inspected before use to ensure they are in good condition and functional. Article 18: Eating or drinking is strictly prohibited in the workplace. Workers should take a bath at the designated location every day before meals and after work, change into their casual clothes, wash their face and hands with soap, and brush their teeth and rinse their mouth. Article 19: The workplace shall be equipped with first-aid kits for rescuing personnel, and there shall be a dedicated person on duty. Article 20: When the concentration of oil and gas inside the tank exceeds the allowable level due to the effects of the operations, the personnel carrying out those operations must evacuate the site immediately. Re-ventilate until the oil and gas concentration drops to the specified level before continuing work. Article 21: When the concentration of oil and gas in the oil tank and its operating area exceeds 20% of the explosive lower limit of that oil, the area within 35 meters of it (this distance can be reduced by 50% for horizontal oil tanks) is considered a zone at risk of fire and explosion. When entering this facility to carry out tank cleaning operations, the electrical equipment introduced into the facility and its installation must comply with **the relevant regulations on safe electricity use. In this area, strict precautions must be taken to prevent collisions with iron objects and similar items. Article 22: Cleaning operations inside tanks are prohibited when the oil and gas concentration in the work area exceeds 40% of the lower explosive limit of that oil. Article 23: Ventilation or cleaning operations of oil tanks are prohibited during thunderstormy weather (or low air pressure) or in strong winds with a wind force of level 5 or above. Article 24: When inspecting and testing electrical equipment, it must be carried out in a safe area at a distance of 35 meters from the oil tank where the work is being done (this distance can be reduced by 50% for horizontal oil tanks). Article 25: The inlet pipelines used for filling with water or padding fluid shall not be oil transport pipelines, to prevent oil from entering the tank. Article 26: Before carrying out tank cleaning operations, an appropriate amount of fire-fighting equipment shall be placed upwind of the work site, and the on-site fire duty personnel must be fully prepared to extinguish fires. Article 27: Tank cleaning personnel are strictly prohibited from wearing synthetic fiber clothing. Synthetic fiber ropes and synthetic fiber rags must not be used. Gas detectors must wear anti-static clothing and shoes. Article 28: When the oil and gas concentration exceeds 20% of the lower explosive limit of that oil, the use of compressed air is strictly prohibited during tank cleaning operations. The use of steam jets, as well as high-pressure water guns to wash the tank walls or to spray water from the top of the tank, is also forbidden. Article 29: The metal parts such as nozzles in the air, water, and steam pipelines introduced into the oil tank, as well as the hoses used for discharging oil, shall be electrically connected to the oil tank and properly grounded. For metal piping introduced into the tank, a metal bridge should be installed when the resistance between the flanges is greater than 0.03 ohms. Article 30: Mechanical ventilators shall be electrically connected to the oil tank and grounded. Article 31: Ducts shall be made of materials that do not generate static electricity; the use of plastic pipes is prohibited ； It should also make contact with the bottom of the tank or the ground so that static electricity can dissipate quickly. Article 32: Personnel carrying out tank cleaning operations must wear protective equipment such as work shoes and safety helmets. Article 33 Oil tank cleaning operations should be carried out away from the depths of winter or the height of summer. Article 34 The following persons are strictly prohibited from engaging in tank cleaning operations: — Women who are menstruating, pregnant, or breastfeeding. II. Those with severe physical disabilities such as deafness, muteness, or mental retardation. III. Those with severe myopia, epilepsy, hypertension, allergic tracheitis, asthma, heart disease, and other serious chronic diseases, as well as the elderly and frail who are not suitable for cupping therapy. IV. Those with untreated traumatic wounds. Article 35: It is prohibited for persons unrelated to tank cleaning operations to enter the construction site. Article 36: Professional tank cleaning personnel shall undergo a physical examination once a year and have a health record maintained. Article 37: The wastewater and waste residues generated during tank cleaning must be treated, and can only be discharged after meeting the specified standards. Chapter 3: Removal of Bottom Oil Article 38: The specific method for removing bottom oil using water as a medium is as follows: First, after the oil tank is emptied, the amount of oil (water) remaining at the bottom must be accurately measured and recorded, so as to determine the appropriate level of water and the operating time of the water pump. II. When filling with water, an appropriate opening (such as an oil level gauge port) should be selected, and a rubber hose equipped with an electrostatic discharge wire should be extended to the bottom of the oil tank. The flow rate during water filling should not be too high; generally, the initial flow rate should be kept around 1 meter per second. Once the oil-water interface is formed, it is appropriate to adjust it so that it is located 0.5–1 centimeter along the oil outlet pipeline. III. After the water padding is completed, remove the inlet hose from the tank, and use an oil transfer pipeline or a temporarily installed hose to transfer the bottom oil that has been padded into an empty tank, an oil-water separation tank (pond), or an oil drum. Caving in must be strictly prevented here. At the same time, it is also necessary to check by measurement whether the base oil has been completely drained. Otherwise, water should be continued to be added until it is confirmed that the bottom oil in the tank has been drained. IV. After confirming that the bottom oil has been drained for 30 minutes, the oil and gas concentration inside the tank should be tested and recorded through oil measurement ports and other means. Article 39: The specific method for removing bottom oil using mechanical suction is as follows: 1. Allow the oil to flow out naturally through the drain valve until no more oil comes out. II. Remove the valves on the inlet (outlet) oil pipelines to cut off the connection with other oil transfer pipelines or oil tanks, and seal the flanges of the pipelines that have been disconnected from the oil tanks using blind flanges. III. Insert the rubber hose from the other end of the oil inlet (outlet) pipeline into the bottom of the tank, and use a hand pump or vacuum pump (the motor associated with it should be explosion-proof and placed at a distance of three meters from the opening) to draw out the oil at the bottom, then pour it into an empty tank, an oil-water separation tank (pond), or an oil barrel, etc. Here, through measurement, once it is confirmed that the base oil has been completely drained, the oil and gas concentration inside the tank should be tested and recorded via oil measurement ports, oil discharge ports, etc., thirty minutes later. Article 40: After the bottom oil has been drained, it is advisable to use a hand pump or vacuum pump to extract the water remaining at the bottom of the tank and send it to a waste water tank or similar location; direct discharge into the sewer system is strictly prohibited. Chapter 4: Removal of Oil Vapors Article 41: Before removing oil and gas, a thorough inspection should be carried out to determine whether the bottom oil (water) has been removed as required. II. Have all pipeline systems of the oil tank been properly disconnected (broken or capped)? III. Whether the cathodic protection system of the oil tank has been effectively disconnected, etc. Article 42: To improve the dispersion effect of oil and gas, it should be released as high into the air as possible. Article 43: During operation, mechanical or adequate natural ventilation shall always be provided. Article 44: When mechanical ventilation is used to remove oil and gas, the ventilation volume shall be greater than the rate of emission of residual oil. Mechanical ventilation should employ positive pressure ventilation; negative pressure suction shall not be used. Explosion-proof fans should be installed at the upper air inlet. Article 45 General operating procedures for mechanical ventilation: 1. Open the light holes and oil level measurement holes at the top of the tank, and remove the breather valve, etc. II. Open the manhole at the bottom of the oil tank, and connect the fan to this manhole using an air duct. After verification, start the fan to enable forced mechanical ventilation. III. Countercurrent intermittent ventilation. That is, every four hours of ventilation, with a one-hour interval in between, over a period of twenty-four hours or more; the ventilation rate should be more than ten times the volume of the oil tank. Only after the concentration of oil and gas reaches the specified level can appropriate breathing equipment be worn and necessary protective measures taken before entering the tank to carry out work. IV. For oil tanks with good air circulation, natural ventilation can be used for more than ten days; after testing to ensure that the concentration of oil vapor reaches the specified level, appropriate breathing equipment and protective measures must be worn before entering the tank to carry out work. However, if welding is required, mechanical ventilation must be employed. Article 46 The general operating procedure for flooding to displace oil and gas is: 1. Remove the valves on the inlet and outlet pipelines. II. The end close to the oil tank is connected to a water filling pipeline, with a valve installed there to control the water flow rate; the other end is sealed with a blind flange. III. Shut off or close the expansion oil pipe valve. IV. Install the overflow hose fittings at appropriate openings on the top of the tank; the diameter of the overflow pipeline should be larger than that of the inlet pipeline. V. After verification, start the water pump to fill the tank slowly (the initial flow rate should be controlled at 1 meter/second). Gradually increase the flow rate once the water level exceeds the population height ； When the water level in the tank reaches 3/4 of its capacity, the flow rate should be gradually reduced ； When the water level gradually approaches the upper edge of the tank body, water filling should be paused; the tank should then be left to soak for 24 hours, after which the fan can be started to remove oil and gas. VI. Then restart the water pump to continue filling the tank slowly until it is full, allowing the water and oil gas to flow through the drainage pipes to the sewage tank and other locations. VII. After a certain period of time, water filling can be stopped, and the wastewater can be discharged to sewage tanks or similar locations through sewage pipelines. Direct discharge into the sewer is strictly prohibited. VIII. When the wastewater level drops to its lowest point, the filling pipeline can be removed; the suction pipe of the hand-cranked pump is then inserted through this opening into the bottom of the oil tank, thereby pumping the water accumulated at the bottom of the tank to a waste water tank or similar location. Article 47: For steam pipelines using low-pressure steam to displace oil and gas, the pipe diameter and steaming time are generally as follows: for oil tanks with a capacity of less than 1,000 cubic meters, when the pipe diameter is 50 millimeters, the steaming time is 15 hours or more. For oil tanks with a capacity of over 1000 cubic meters and a pipe diameter of 75 millimeters, the time is over 20 hours. For oil tanks with a capacity of over 3,000 cubic meters and a pipe diameter of 75 millimeters, it is 24 hours or more. For oil tanks with a capacity of over 5,000 cubic meters and a pipe diameter of 75 millimeters, it is 48 hours or more. Article 48: The steam pressure should not be too high; it should generally be controlled at around 0.25 megapascals. Article 49 General practices for using steam to drive off oil and gas: 1. First, pour a small amount of water into the tank. II. Ensure proper grounding of the steam pipes (these pipes are usually arranged in a cross shape, with small holes drilled evenly along them); use bamboo or wooden rods to extend the steam pipes into the oil tank up to one-quarter of its depth, starting from the manhole. III. Open the vent holes, etc., to provide the oil tank with a sufficiently large steam discharge pathway. IV. Fix the steam pipeline outside the tank, and then slowly introduce steam. When the temperature inside the tank rises to 65°C–70°C, maintain it for the required time. Article 50: For oil tanks that have been purged with steam, care must be taken to prevent a vacuum from forming when the tanks cool down, as this could damage the equipment. Chapter 5 Gas Detection Article 51 The scope of gas detection shall include the oil and gas concentrations in areas such as storage tanks containing Class A, Class B, and Class C A oils, as well as within a 35-meter radius around these areas where oil vapors may be present. Article 52: At least two explosion-proof combustible gas detectors of the same model and specifications must be used, and they should be operated by trained specialists. If there is a significant difference in the readings from the two detectors, the testing must be repeated. When hot work is required, an explosion-proof combustible gas detector should also be added. Article 53: Gas detection shall be carried out along the circumferential direction of the oil tank, with attention paid to selecting low-lying areas and dead corners where oil and gas tend to accumulate. For floating roof tanks, the oil and gas concentration above the floating deck should also be measured. Article 54: Before each ventilation session (including re-ventilation after intermittent ventilation) and before workers enter the tank, oil and gas concentration tests must be conducted carefully, and detailed records must be kept. Article 55 During operation, oil and gas concentration tests shall be conducted at regular intervals. During normal operation, it should be done no less than twice every eight hours to ensure that the oil and gas concentration remains within the specified range. Article 56: For the testing of oil and gas concentrations in the context of hot work analysis, both combustible gas detectors and explosion detectors shall be used for measurement, and these tests must be conducted within 30 minutes prior to starting the hot work. If the hot work is interrupted for more than 30 minutes, a new hot work analysis must be conducted. All samples should be retained until after the hot work is completed. Article 57: Testing instruments must be within their valid calibration period to be used. Chapter 6: Operations Inside the Tank – Article 58: The inspection personnel shall conduct another measurement of the oil and gas concentration 30 minutes before entering the tank, to ensure that it is within the specified allowable limits, and shall keep a record of this. The tank cleaning operation supervisor, together with the safety inspectors, conducts an on-site inspection. Article 59: Once the safety (supervision) personnel have entered their posts, the workers may proceed with work inside the tank. Article 60: When working inside a tank while wearing isolated breathing apparatus, operators are generally rotated every approximately 30 minutes. Article 61: Workers should wear life-saving signal ropes around their waists, with the ends of the ropes remaining outside the tank so that they can be used to rescue the workers at any time. Article 62: Common practices for removing debris: 1. Manually use special copper (aluminum) shovels or wooden rakes fitted with hard rubber to remove debris and rust from the bottom and walls of the tank. 2. Collect the debris in special covered aluminum barrels, and then transport it out of the tank manually using appropriate methods or by handcart. III. After spreading lime or sawdust at the bottom of the tank, sweep it away using a copper shovel or a bamboo broom. IV. For oil tanks with severely corroded tank walls, when the concentration of oil and gas drops below 20% of the lower explosive limit, high-pressure water can be used for flushing. Article 63: If a oil tank is to undergo non-destructive testing or internal anti-corrosion treatment, rust and scale should be removed further using copper brushes, followed by cleaning with a metal detergent, and the surface should be wiped clean with a cotton mop. Article 64: Oil tanks that are contaminated should be sprayed with water during operations to prevent spontaneous combustion. Chapter 7 Lighting and Communication Article 65 Explosion-proof lighting equipment must be used. Its minimum suspension height should generally not be less than 2.5 meters, and it must be securely fixed. The supply voltage should not exceed 12 volts, and a leakage protector must be installed to ensure that each light has its own switch and protection. Article 66: For lighting during the cleaning of light oil tanks, explosion-proof flashlights should generally be used for local illumination. The voltage of a handheld lantern should not exceed 12 volts. Article 67: During tank cleaning operations, close communication should be maintained, and explosion-proof communication equipment should be used. Chapter 8: Inspection Article 68: Cleaned oil tanks should generally meet the following requirements: For tanks used to store high-grade lubricants or those with significantly different technical requirements, there should be no visible rust, impurities, water, or oil residues. When wiped with a clean cloth, no noticeable dirt, sludge, or traces of iron or calcium should be present. II. For regular cleaning, when no other oils are stored, the sediment and oil deposits on the bottom, walls of the tank, and its attachments should be removed, so that there are no visible deposits or oil residues. III. For oil tanks that need to be cleaned as part of maintenance and internal anti-corrosion work, all oil stains, rust, and deposits must be thoroughly removed. The surface should be wiped with a clean cloth until no traces of dirt, sludge, or rust remain, allowing the natural color of the metal to show through; only then can internal anti-corrosion treatment and maintenance be carried out. Article 69: After passing the inspection, the oil tank shall have its manholes, access holes, etc. sealed immediately under supervision, the relevant pipelines shall be connected, and the tank’s original system shall be restored. Generally, the principle of \"who installs it, who removes it\" should be followed to prevent omissions. Chapter 9: Other Provisions Article 70: After the oil tank cleaning is completed, professional technicians and maintenance personnel shall conduct a thorough inspection of the oil tank’s bottom plate, ring plates, and other accessories, and carry out necessary repairs and maintenance. Thickness inspections should be carried out on the bottom plate, bottom ring plate, and top plate, with records kept. Article 71: In conjunction with the cleaning of the oil tank, anti-corrosion treatment of the inner walls of the tank bottom plate and the bottom ring plates below the oil inlet (outlet) pipelines shall be carried out. The coating height should not be too large; otherwise, measures for static discharge should be considered. Chapter 10: Supplementary Provisions Article 72: Relevant enterprises may formulate detailed safety operating procedures for oil tank cleaning in accordance with these regulations and taking into account the specific conditions of their respective units.

1. Pour the remaining oil in the tank into a similar tank or another tank. 2. Open the light-transmitting holes, manholes, and drain holes. 3. Notify the relevant departments to conduct a gas analysis; entry into the tank is permitted only if the hydrocarbon content is below 1% and the oxygen content is above 20%. 4. Introduce steam into the tank as required; be careful to avoid injury from the steam, and use a high-pressure water gun to flush the emulsion into the drainage system after it is introduced into the tank. 5. Check the sealed state of the tank and keep records

Let me answer this question. It generally depends on the type of storage tank; special tanks require special treatment methods. The general steps for cleaning a tank are as follows: 1. Pour out the remaining oil in the tank into another tank of the same type or into other tanks. 2. Open the light-transmitting holes, manholes, and drain holes. 3. Notify the relevant departments to conduct a gas analysis; entry into the tank is only allowed when the hydrocarbon content is below 1% and the oxygen content is above 20%. 4. Introduce steam into the tank as required; be careful to avoid injury from the steam, and use a high-pressure water gun to flush the emulsion into the drainage system after it is introduced into the tank. 5. Check the sealed state of the tank and keep records

Something that is encountered frequently in work:) 1. First, pour the oil in the tank until it reaches a level close to the inlet of the pump. Then open the drain valve and close the tank bottom valve connected to the pump inlet. During routine inspections, the pump operator adjusts the opening degree of the pump outlet valve based on the pressure reading on the outlet pressure gauge, aiming to remove all the oil from the tank until it is empty; usually, the pressure drops below 0.1 M. 2. Organize the construction workers to install a blind flange on the side of the tank bottom valve that is closest to the tank, in order to isolate the oil, secure it with wire, keep records of this action, and ensure that the operators are informed about it. 3. Submit an application in advance to the security department to request the use of fire-fighting water volume and time period. 4. Open the tank top gauge port and light-transmitting port. 5. Contact the tank cleaning company to bring the oil tank to the site and place it at the cleaning hole; lay an oil-proof cloth between the cleaning hole and the oil tank to prevent oil from leaking and contaminating the environment. 6. The tank cleaning party shall go to the equipment department to obtain the work order, risk assessment, and documents permitting vehicles to enter the explosion-proof area. 7. The tank cleaning party shall use explosion-proof tools and wear protective equipment, and shut down all communication facilities. An oil pumping unit shall be brought to the site and connected to an electrostatic grounding system to prevent the generation of static electricity. 8. To open the cleaning hole, first loosen the bolts at the bottom so that the oil can flow out to the oil tank. The oil is then pumped out using a tank truck; once the tank truck is full, the bolts at the bottom should be tightened again. After the tank truck has unloaded its contents, proceed to the next step until all the oil in the tank has been removed. 9. Open the cleaning holes and manholes, connect the fire-fighting water hose at these manholes, and use it to clean the sludge and residual oil inside the tank against its walls and bottom until clean water flows out. Then, use a tank truck to remove the wastewater and dispose of it at the location designated by environmental protection officials. 10. Ensure ventilation for 24 hours, contact laboratory personnel for analysis; once the results are satisfactory, issue a work order to enter the tank for cleaning. A supervisor and fire extinguishers must be available. Personnel working inside the tank should exit after 30–45 minutes to rest or have someone else take over the task. The above are summaries drawn from work experience; they are not necessarily comprehensive. Sometimes, depending on the structure of the tank and the medium involved, certain aspects take priority, so they are not listed here one by one.

Are there specialized cleaning companies that handle this?

This post was last edited by Chuyun Primary School Student on 2009-5-8 00:09. 1. Empty the tank. Pour the remaining oil in the tank into other tanks containing similar oil; when the liquid level is below the material inlet and outlet lines, use the water cut valve along with a diaphragm pump to empty the tank. 2. Open the manholes, light-transmitting holes, and sewage outlets to steam the tank. The steaming time is determined based on the size of the storage tank; it generally takes 48 hours, and longer for tanks storing heavy oil. 3. Then rinse the storage tank with water. Pay attention to the discharge of wastewater. 4. The quality control department checks the oxygen level; if it is within acceptable limits, work can proceed inside the tank. If necessary, a fan can be used to ensure proper ventilation. There must be someone to supervise outside! Note that before opening the tank, the tank under maintenance must be isolated from the system, and blind plates must be installed at all connections! This is very important

First, pour out the oil in the tank. Close the inlet and outlet valves and install blind flanges. Open the light-transmitting holes, steam the tank as required, open the manholes and drain ports, and clean them with high-pressure water. Test the oxygen level; once it meets the requirements, entry into the tank for cleaning is permitted.

The main thing to pay attention to when emptying a tank is safety. First is ventilation; it is best for those entering the tank to carry oxygen ； Second is explosion protection; appropriate tools must be used.

General steps for cleaning storage tanks: a. Remove any remaining material at the bottom of the tank. This can be done using a dedicated pipe for pumping out liquid from the bottom of the tank, or by filling the tank with water and then pressing oil into it from a lower tank, or using a pumping line to remove the oil from the bottom of the tank. Another method is to slowly fill the tank with water and collect the remaining oil through the manhole at the bottom of the tank. Valves such as those for material inlet and outlet in the storage tank, expansion lines, water cut-off lines, and heaters should be tightly closed, secured with wire, or fitted with blind flanges to prevent oil or steam from entering the tank. Open the lighting hatch at the top of the storage tank, and heat the tank using steam via the manhole at the bottom of the tank or a temporary steam connection. The manhole at the bottom should be temporarily sealed. The recommended steaming time is as follows: 48–52 hours for tanks storing benzene-based products, 24–36 hours for kerosene and diesel tanks, and 24 hours for heavy oil tanks. After the steaming process is completed, a safety inspection and sampling analysis are carried out to ensure that the gases inside the tank meet the specified standards; only then is a permit for entering the tank issued, allowing cleaning work to be carried out inside it. A small amount of viscous sediment at the bottom of the storage tank can be washed away into the sewer system using hot water. For solid deposits at the bottom of storage tanks holding heavy oils, high-pressure hot water and manual excavation can be used to completely remove impurities, rust, sludge, etc. from within the tank, which should then be transported to a safe location or buried deep underground ； Finally, clean with sawdust; after rinsing the bottom and walls of the tank with water, wipe them clean with a cloth. After cleaning the containers, they are inspected and approved by the quality management department; once approved, they are handed over for maintenance or use, while also ensuring good environmental hygiene.