Rules for the technical operation of tanks: norms and requirements

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

This article describes the basic requirements, norms and rules for the technical operation of tanks intended for the storage of oil and oil products. In addition, the main provisions are given on the use of various methods of non-destructive monitoring of the condition of tanks, the protection of structures made of special steel from corrosion and the harmful effects of the environment, the reduction of oil losses during technological operations, and the prevention of oil spills. Attention is paid to the procedure for carrying out repair work at facilities such as tanks for storing oil and oil products.

Regulatory legal acts and documents

Detailed instructions for the repair and operation of tanks was approved by the State Committee for Oil and Gas of the Soviet Union back in 1986year. Such a country no longer exists, and this document has not lost its significance. Many oil producing and oil refining companies, when developing their own documentation, take these rules for the technical operation of tanks as a basis. The status of this document is invalid. But it has not lost its relevance. Many experts recommend that all interested parties familiarize themselves with the rules for operating Rosneft tanks.

Fundamentals of safe operation of storage tanks for oil and petroleum products

In accordance with the rules for the technical operation of storage tanks for combustible materials, all engineers and technical personnel of the enterprise must have a good knowledge of the design and features of systems for pumping and storing petroleum products. This requirement is well founded and understandable. After all, an ignorant person by his actions can provoke a large-scale man-made disaster., if the assembly was carried out without violations of the regulations.

General requirements for the design and reliability of steel tanks

Capacities for storing oil and oil products are being carried out,as a rule, from special construction grades of steel. However, there is no universal standard for and form. Tanks can be made both in vertical execution, and in vertical. In addition, for certain purposes and under certain circumstances, spheroidal steel containers can be made. In some cases, enterprises give orders for the manufacture of special containers. Such equipment is much more expensive. But some major players in the energy market can afford it (for example, Rosneft). The rules for the technical operation of tanks in this regard may vary. But in general, a set of rules that ensure safe operation is applicable to any enterprise that is engaged in the storage and processing of oil and oil products.

Features of vertical tanks

Vertical tanks can have a variety of useful volume - from 100 to 50,000 cubic meters. They can be built both above ground, on and under it. In addition, such tanks can be used both for storing liquids without pressure and under it. Tanks capable of operating at pressures up to and including 2,000 Pascals are referred to as overpressure tanks. For certain purposes, containers may be required that can operate at high pressures (up to and including 70,000 Pascals). The main customer of such products is Rosneft. The rules for the technical operation of tanks can vary significantly. After all, vesselswhich work under pressure, require more thorough inspection and increased attention from both engineering and operating personnel. This defines the rules for operating vertical tanks.

The roof of such vessels can be either stationary or floating. And this also affects the procedure and rules for the technical operation of oil storage tanks. The stationary roof can be made in the form of a sphere, a cone, etc.

It is not always possible to use a welded joint for the manufacture of tanks. It has its drawbacks, which can become critical (for example, in certain weather conditions). An alternative to welds is riveting. The labor intensity of the production of such tanks is an order of magnitude higher, but the reliability is several times higher than cheaper welding. When welding, sheet material can be butt-jointed, overlapped (or partially overlapped). Rivets can connect sheets with an overlap or butt. In the second case, special overlays will be needed.

Features of horizontal tanks

The capacity of horizontal steel tanks is an order of magnitude smaller than vertical ones (from three to two hundred cubic meters). They can also be mounted both on the ground and below it. Such tanks are by default designed to withstand a pressure of 4000 pascals. The bottom of such tanks can be flat, conical, or spherical.

Each tank car can only be operated with all necessary auxiliary equipment. Storage of oil and oil products in a dismantled tankforbidden. All containers in which gasoline is stored must be coated on the inside with a special protective layer aimed at ensuring static spark safety.

During the manufacture of the tank, its dimensions cannot exceed the tolerances. These indicators are strictly regulated and spelled out in the design documentation.

Tanks of small capacity (up to eight cubic meters inclusive) should have a flat bottom. A flat bottom is also allowed for larger tanks. But this condition must be agreed with the customer.

Procedure for receiving oil and oil products into tanks

The rate of supply of bulk cargo (oil and oil products) to an empty tank should not exceed one meter per hour. This restriction is maintained until the intake-distribution pipe is filled. After that, it is allowed to increase the speed to three and a half meters per hour.

It is very important to organize the supply of a new batch of oil products into the tank in such a way that it is carried out below the level of liquid already in the tank.

To avoid air pockets, tanks must be filled and emptied completely.

No splashing, spraying or rough and violent mixing of petroleum products is allowed. In other words, filling using a free-falling jet of liquid is not allowed. The distance from the end of the loading pipe to the bottom of the tank should not be less than 0.2 meters. In this case, the jet should be directed along the wall. These andsimilar requirements can be found in the rules for the technical operation of tanks and Rosneft, and other oil companies. This norm is also contained in the old requirements developed and approved back in the days of the USSR. However, it should be said that the status of the rules for the technical operation of tanks of 1986 is not valid. Currently, all large companies have the necessary personnel in their staff, who are engaged in monitoring the situation, developing and adjusting their own regulatory and technical base.

In accordance with the rules for the operation of tanks of main oil pipelines, pumping oil products into a tank can only be started if there is a written order from the responsible head of transport operations.

It is necessary to tear off valves and special tank valves without sudden movements, without resorting to the use of auxiliary means. If the valves are equipped with an electric drive, then an alarm must be installed that clearly indicates the state of the valve (closed or open). Any transfer is strictly required to be recorded by the senior operator in the service log.

Rules and procedures for stripping oil and petroleum products storage tanks

In accordance with the rules for the technical operation of metal tanks, cleaning of containers must be carried out in compliance with the requirements and rules of fire safety at work.

The frequency of these works is carried out by GOST 1510. Whenstorage of jet fuel, aviation kerosene, as well as oils for use in aviation, cleaning is carried out at least once every six months. When used in the injection system of a filter of forty micrometers, it is allowed to carry out cleaning work at intervals of once a year. In the case of storage of other oils, gasoline for automotive vehicles, diesel fuel, cleaning should also be carried out once a year. The frequency of these types of work for tanks with fuel oil and motor fuel. It is mandatory that the tank car be cleaned before changing the product, before carrying out non-destructive testing by a flaw detection specialist.

In accordance with the rules for the operation of oil tanks, cleaning is preceded by preparatory work: installation of process and auxiliary pipelines (water, steam), preparation and adjustment of equipment for surface cleaning. The sequence of work cannot be broken. It is indicated in the work permit. This document is signed by a responsible official.

Only a competent and experienced engineer who has been trained in the relevant courses and advanced training in the relevant department can manage such work. He must arrange for all workers to be briefed on safety and accident management before starting work.

Rules for the technical operation and repair of tanks strictly regulate the procedure for cleaning the inner surface of the tank. First of all, the container must be completelyfree from any residues of petroleum products. For this, a special suction hose is used. For more complete and thorough cleaning, the tank is filled with water. The density of oil and its derivatives is much less than the density of water. Oil and fuel float to the surface, after which they are eliminated.

Safety for cleaning inside tanks

The rules for the technical operation of oil tanks prohibit the use of general-purpose equipment for cleaning. All devices and devices must be explosion-proof. Wiring must also be special.

In order to avoid accidents, the pumping speed of the mixture of oil and water should not exceed certain limits, taking into account the recommendations for protection against the occurrence of static electricity.

In the event that the remaining flammable products are pumped out, the lower one must ensure that the lower hatches are hermetically closed. This category includes substances whose flash point is below 61 degrees Celsius.

After the complete removal of all residues, all pipelines are disconnected from the tank and special plugs are installed. The installation of plugs is recorded in a special log. This is necessary in order to avoid confusion when putting the tank into operation after cleaning work, as well as for safety reasons.

It is forbidden to carry out work on filling and emptying tanks located at a distance of less than forty meters from the tank being cleaned.

When carrying out work on cleaning the inner surface of the tank, it is necessary to exclude the admission of unauthorized persons to the work area. Workers involved in the work must be provided with all necessary protective equipment (goggles, respirators, gloves, etc.) and degassing equipment.

Degreasing the inner surface of the container is carried out by spraying and applying the active substance (potassium permanganate solution in water) using a nozzle.

When a critical mass of waste oil products accumulates in water (1500 milliliters per liter of liquid), then its further use is excluded. Such a liquid needs to be filtered and cleaned from petroleum products.

Protecting the internal surface of tanks from corrosion

In accordance with the rules for the technical operation of steel tanks, the inner surface of storage tanks for petroleum products can be covered with paints or combined metallization and paints to protect against corrosion. The application of any coating is preceded by careful surface preparation (cleaning) and other preparatory work.

The choice of one or another method of protection depends on many factors. First of all, from the aggressiveness of the impact of oil products and the environment on the elements of metal structures.

It is recommended to start treatment with anti-corrosion coatings from above. The paintwork is applied last to the bottom. However, when painting the inner wallstanks with a floating roof, a different order is allowed: initially a coat of paint is applied to the bottom and roof. Then water is poured into the tank. She raises the roof, and the painting of the inner walls is carried out afloat. The same is done when painting the walls of tanks equipped with pontoons. This procedure is established by the rules for the technical operation of oil trunk pipeline tanks.

Painting of internal surfaces is carried out in accordance with a specially developed project. This document specifies the degree of cleaning of the surface before applying the paint, acceptable and recommended methods of cleaning, the number of coats of coating and other information. The service life of this coating is three years. After its expiration, the paintwork must be completely changed. If this requirement is neglected, then the surface will begin to actively corrode or quickly become unusable. Oil leaks and environmental pollution are not ruled out.

Features of tread protection

Regulations for the technical operation of tanks ("Nedra", Moscow, 1988) approve the features of the organization and device of the protective protection of tanks. When designing it, it is necessary to take into account the alkalinity, mineral composition and chemical composition of groundwater.

As a protector for corrosion protection of carbon steels, materials such as zinc, magnesium and alloys based on them and aluminum are used. Mounting of tread plates on the inner surface of the tank is preceded by their careful preparation. She isconsists in applying an insulating layer to one of the surfaces of the plate.

Protectors can be mounted both on the bottom of the tank and on its walls. The area on which the protector will be attached must be cleaned of dirt and rust. Epoxy resin is ideal for fastening. This substance reliably sticks the protector to the surface and serves as a good insulating material. The contact of the tread with the bottom is carried out by welding a rolled steel of small section.