RU2548076C2 - Cleaning method for tanks intended for oil and oil products storage and transportation - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention is related to oil industry, in particular, to processes of collection, accumulation, storage and transportation of oil and oil products in tanks of different purpose and design. Cleaning of tanks includes delivery of washing out agent, dilution and stirring of bottom sediments, discharge and transportation of diluted bottom sediments to the processing stage. At that washing out, dilution and stirring of bottom sediments is made with use of remote-controlled robot-aided guns equipped with video surveillance and lighting system placed inside the tank through the lower process hatches. Discharge of diluted bottom sediments is made by pumps installed at remote-controlled mobile units, which are also placed inside the tank through the lower process hatches while washing out and transportation are made by the washing out agent at temperature that depends on ambient air temperature up to 310°C under pressure of 1.0-10.0 MPa. Washing of the tank head, walls and bottom is made by orbital washing heads placed in the tank head hatches to which delivery of the washing out agent is switched. When the low explosive limit is exceeded inert gas is delivered to the tank automatically.

EFFECT: development of safe and effective cleaning of oil tanks from sediments and further processing of the above sediments.

2 dwg, 1 tbl

Description

The invention relates to the oil industry, oil production and oil refining industry, in particular to technological processes for the collection, accumulation, storage and transportation of oil and oil products in tanks for various purposes and design.

The invention can be used to clean oil tanks from deposits (mechanical impurities bonded with paraffins and resinous substances) that are formed on the bottom, walls and roof, i.e. on the inside of the tank.

A tank for oil and oil products (hereinafter referred to as the tank) is a technical tool intended for the reception, storage, transportation, dispensing and metering of oil and oil products.

To ensure the operational reliability of tanks, it is necessary to comply with the rules of their technical operation, control, detection and elimination of defects. A prerequisite for the implementation of these works is the timely repair of tanks with preliminary cleaning of oil product residues and their deposits.

Cleaning the inner surfaces of reservoirs from oil product residues is an integral part of the oil product supply process.

Currently, work on cleaning tanks from deposits is carried out both manually and mechanically.

With the manual method, cleaning is carried out by several workers (from six to 20 people) using improvised means - scrapers, shovels, water hoses, etc. Workers perform this work in special personal protective equipment (respiratory protection, eyes, hands, skin and feet) using intrinsically safe tools.

Thus, when performing work, there is a significant risk of emergencies, injury to health, acute poisoning by vapors of harmful substances, injuries (as part of the work is carried out at height), fire and explosive situations due to the accumulation of vapors of volatile, flammable substances, environmental pollution. The cleaning time with this method is about one month, the cleaning quality is satisfactory.

With a mechanized method, cleaning is usually carried out using a controlled manual water gun, which is placed inside the tank. When performing cleaning in this way, the time required to complete the work is significantly increased, since it is periodically necessary to stop the process, enter the worker inside the tank, move the water gun, change the direction, the angle of the water gun and the movement of the water jet.

Moving the gun, changing the direction and angle of the gun’s water jet inside the tank is carried out manually, which, in turn, also poses a significant risk of emergencies, personal injury, acute poisoning by vapors of harmful substances, the occurrence of fire and explosive situations due to accumulation vapors of volatile, flammable substances, environmental pollution. The cleaning time with this method is 2-3 weeks, the quality of cleaning is satisfactory.

A known method of cleaning an oil tank containing a layer of oil residues, in which the residual oil is diluted to obtain a liquid oil-containing product (see US patent No. 5078799, publ. 07.01.1992).

The product is removed from the tank and subjected to purification to form a refined oil product. The remaining crude part is recycled in the tank and distributed inside the tank in the area located above the surface of the layer of oil residues.

The disadvantage of this method is the inefficiency of the dilution of oil residues, high energy consumption and long periods.

A known method of cleaning the tank from deposits according to the patent of the Russian Federation No. 2196062, publ. 01/10/2003. The specified method includes the flow of erosion fluid through a controlled barrel with a nozzle to the surface of sediments, erosion of sediments by a stream of erosion fluid from a controlled barrel with a nozzle and the removal of eroded suspended sediments simultaneously with the erosion process. The erosion is carried out by separating the sediments into separate sections with a jet of erosive fluid, and the barrel with the nozzle is controlled depending on the state of the sediments over the area of the tank bottom. During cleaning, the composition of the mixture of sediments with erosive fluid is monitored and the erosion zone is expanded while the suspension of sediments is reduced.

From the advertising brochure of the company "MegaMAX", publ. 08/31/2007 on the Internet on the website http://www.kmtinternational.com/russian/pdf/MegaMacs_presentation_ marketing_broshure.pdf, a method of cleaning tanks intended for storage and transportation of oil and oil products, including supply erosion agent, liquefying and mixing sediments, removal and transportation of liquefied sediments to the processing stage, while washing, liquefying and mixing sediments is carried out using remotely controlled robotic guns, placed water inside the tank through the lower technological hatches, the removal of liquefied sediments is carried out by pumps, also placed inside the tank through the lower technological hatches, washing and mixing is carried out with a hot washing agent under a pressure of 20 bar, after which the roof, walls, bottom of the tank are washed with orbital washing heads, to which the supply of the erosion agent is switched, and when the lower level of the explosive limit is exceeded, the inert gas is automatically supplied to the tank.

The disadvantages of the above methods are:

- the duration of the process and additional labor costs due to the need for stops and, as a result, the restart of the cleaning process to control the quality of the wash (with poor visibility when entering the tank), the composition of the mixture of deposits and erosive fluid;

- the presence of maintenance personnel in the hazardous area (gassed environment) associated with the need to manually move the pump out of the pump inside the tank, where exposure to harmful vapors occurs.

The objective of the claimed invention is the creation of a safe, continuous, fast and efficient way to carry out work on cleaning oil tanks from deposits with their subsequent processing (separation into oil, water and solid phase (cake)).

The object of the invention is a method for cleaning tanks intended for storing and transporting oil and oil products, including supplying a scouring agent, diluting and mixing sediments, discharging and transporting diluted sediments to the processing stage, while washing out, diluting and mixing sediments is carried out using a remotely controlled robotic gun permanently installed inside the tank through the lower technological hatches, the removal of liquefied deposits is carried out by pumps, also placed inside the tank through the lower access hatches, washing and mixing is carried out with a hot washing agent under a given pressure, after which the roof, walls, bottom of the tank are washed by means of orbital washing heads, to which the flow of the washing agent is switched, and when the lower explosive limit is exceeded automatic supply of inert gas to the tank, it is decided that the erosion, dilution and mixing of the deposits is carried out after sealing the lower technologies hatches and hatches of the roof of the tank using one or more remotely controlled robotic guns with a video surveillance system and lighting, remotely controlling the quality of erosion through a video surveillance system, pumps performing the removal of liquefied deposits, the quality of which is also remotely controlled by a video surveillance system, is installed on those manufactured in explosion-proof execution with the hydraulic drive of self-moving installations with remote control, placed in the morning of the tank through the lower technological hatches and made with the possibility of placing on them robotic guns with a video surveillance system and lighting, orbital washing heads, the body of which is made of stainless steel and by which they wash the roof, walls and bottom of the tank, are placed in the roof hatches of the tank, Moreover, robotic guns with a video surveillance system and lighting are also installed in the lower technological hatch and / or on a self-moving installation with remote control, eraturu scouring agent selected in the range up to 310 ° C, depending on the ambient temperature, and its pressure is from 1.0 to 2.0 MPa.

The claimed invention is illustrated by graphic materials, where in FIG. 1 (top view) and FIG. 2 (side view) is a schematic flow diagram of cleaning the tank from deposits, on which:

1 - reservoir;

2 - lower technological hatch;

3 - debris (square) of the tank 1, excluding in case of depressurization of the tank 1 spill of oil on the surface;

4 - a pump mounted on a self-propelled installation with remote control, configured to install a robotic gun with a video surveillance system and lighting 5. This installation is designed to remove (and wash out, if a robotic gun with a video surveillance system and lighting 5 is installed on it) from deposits from the tank 1. Installation is made in explosion-proof execution with a hydraulic drive. The pump has a capacity of 10 m ³ / h or more and creates a pressure of 0.1 to 2.0 MPa;

5 - a robotic gun with a video surveillance system and lighting, designed for erosion of deposits by a stream of erosion agent under pressure from 1.0 MPa and a selected temperature. The angle of inclination and rotation is controlled remotely, and the built-in video surveillance system allows you to control the process and control the quality of erosion and removal of deposits. It is allowed to use one or more robotic guns with a video surveillance system and lighting.

6 - orbital washing head, placed in the roof hatch of the tank 13 and intended for washing the roof, walls and bottom of the tank 1 with a washing agent. It is allowed to use one or more orbital washing heads. Washing is achieved by rotation of the specified head, having two nozzles, in horizontal and vertical planes. This allows you to effectively create a “sphere” inside the tank 1. Use the stainless steel housing of the orbital washing head during the full working cycle to use it in an aggressive and explosive environment;

7 is a supply line of the washing agent passing through the roof hatch of the tank 13 from the processing unit 12 to the orbital washing heads 6;

8 - supply line of the washing agent passing through the lower technological hatches 2 from the technological installation 12 to the robotic guns with a video surveillance system and lighting 5;

9 - a line for pumping sediments passing through the lower technological hatches 2 from the pumps 4 and then sequentially to the technological units 12 and 11;

10 - inert gas supply line, for example nitrogen, passing through the lower access hatches 2 inside the tank 1 from the process unit 11, designed to supply inert gas when the lower explosive limit is exceeded inside the tank 1. Inert gas is generated by the station, which is part of the process unit 11, and is fed through the lower technological hatch 2 in automatic mode using a signal from a gas analyzer installed inside the tank 1;

11 - technological installation, including equipment designed to perform the process of phase separation for oil, water and solid phase (cake), control of technological equipment, installation for supplying an inert gas (nitrogen, etc.);

12 - technological installation, which includes a set of equipment designed to perform the process of removing large mechanical impurities (sand, rust, etc.), heating and sludge of recovered sediments and trapping of petroleum products;

13 - the roof hatch of the tank, designed to fix the orbital washing heads 6, for measurements, inspections, access of sunlight into the tank 1 and ventilation during repair and cleaning of the tank 1 from deposits.

Additionally, a mobile system for treating industrial, produced water or process fluids can be included in the technological scheme.

The following liquids are used as a scouring agent for erosion of deposits:

- process water with a temperature of up to 100 ° C;

- produced water with a temperature of minus 20 to 100 ° C;

- saline solution, for example, based on calcium chloride of various concentrations with a temperature of minus 55 to 100 ° C;

- ethylene glycol, an aqueous solution of ethylene glycol of various concentrations with a temperature of minus 60 to 190 ° C;

- solutions based on surface-active substances (surfactants) with a temperature of minus 50 ° C or more;

- solutions based on diesel fuel with a temperature of minus 50 to 180 ° C;

- water vapor with a temperature up to 310 ° C.

The erosion agent may include various additives, such as demulsifiers, corrosion and scale inhibitors, dispersants, depressants.

The technological process by which the claimed method for cleaning tanks intended for storage and transportation of oil and oil products is carried out (implemented) includes the following steps:

1) preparatory work, including preparation of the tank (removal of technological residue, preliminary degassing or phlegmatization), determination of the amount of deposits, preparation of equipment, collection, commissioning, connection of devices, equipment and communications, checking their operability and tightness;

2) the implementation of the cleaning (inclusion, process control, device management, completion);

3) verification of the completeness and quality of cleaning;

4) disposal and processing of cleaning products;

5) delivery of the tank to the customer;

6) shutdown, collection, conservation of equipment, devices and communications, disposal of waste generated.

Preparation of technological equipment, devices and communications is carried out at a safe distance from tank 1. Preparation of the technological process includes unloading of technological equipment, assembly, commissioning, connection, checking the operability and tightness of technological equipment and communications (lines and sleeves).

Inside the tank 1, through the lower technological hatches 2, self-moving installations with remote control are installed, on which the pumps are located 4. It is allowed to use one or more pumps 4, and also additionally install a robotic gun with a video surveillance system and lighting 5 on the self-moving installation with remote control.

After placing the self-moving unit with remote control inside the tank 1, the pump 4 is connected to the sediment evacuation line 9, connected in series with technological units 12 and 11 by flexible hoses (not shown).

Then, in the case of installation on a self-moving installation with remote control of a robotic gun with a video surveillance system and lighting 5, the latter is connected to the supply line of the erosion agent 8 connected to the technological installation 12.

Robotic guns with a video surveillance system and lighting 5 are installed and fixed in the lower technological hatches 2 and connected to the supply line of the erosion agent 8 connected to the technological installation 12.

Robotic guns with a video surveillance system and lighting 5 in addition to installation in the lower technological hatches 2 and on self-moving installations with remote control can also be installed permanently inside the tank 1.

Through the lower technological hatch 2, an inert gas supply line 10 is drawn into the tank 1 and connected to the processing unit 11.

After the installation of all the above lines is completed, the lower technological hatches 2 are sealed.

Orbital washing heads 6 are installed in the hatches of the roof of the tank 13 and connected to the supply line of the washing agent 7 connected to the technological installation 12 by means of technological hoses (not shown), after which the roof hatches of the tank 13 are sealed.

The control lines of technological devices, electrical communications, a video surveillance system, a remote control line are connected to the processing unit 11.

After connecting all the devices, they additionally check the tightness of the lines and communications, as well as the correct connection of the process equipment, lines and communications.

After verification, begin the direct process of cleaning the tank 1, the inclusion of technological equipment. Monitoring, process control is carried out by one operator using the control panel on the process unit 11.

The implementation of the technological process of cleaning

To remove deposits, include the washing agent feed pumps located in the technological unit 12, then, under pressure, the washing agent 8 feeds the washing agent with a temperature from ambient temperature to 310 ° C (depending on the cleaning conditions) to robotic guns with a video surveillance system and lighting 5.

At the same time, pumps 4, located on self-moving units with remote control in the tank 1, are turned on, through these pumps, the liquefied sediments are removed and directed along the pumping line of sediments 9 in series to technological units 12 and 11.

The liquefaction is carried out due to the circulation and the hydro-monitor effect of the erosion agent with a temperature from ambient temperature to 310 ° C.

The cleaning is carried out continuously, sequentially in two stages, first carrying out the initial cleaning using robotic guns with a video surveillance system and lighting 5 and removing sediments using pumps 4, and then after removing the residue from the bottom surface, finishing finishing using orbital washing heads 6.

In this case, it is allowed to carry out erosion of deposits by robotic guns with a video surveillance system and lighting 5 and orbital washing heads 6 at the same time.

Deposits are washed out through robotic guns with a video surveillance system and lighting 5 under pressure from 1.0 to 2.0 MPa at a temperature of the erosion agent depending on the ambient temperature and the composition of the erosion agent, changing the direction of erosion.

The specified pressure range is due to the temperature of the erosion agent, that is, the higher the temperature of the erosion agent, the lower the pressure sufficient to erode deposits.

In parallel, sediment removal is carried out by pumps 4 with a capacity of 10 m ³ / h and more and a pressure of 0.1 to 2.0 MPa.

Remotely, through the video surveillance system, the operator monitors the technological process and the quality of erosion and removal of deposits. The duration of operations depends on the amount of deposits in tank 1.

Pumps 4 divert sediments along the line for pumping sediments 9 to the technological unit 12 and then to the technological unit 11, where the separation of oil sludge into oil, water and solid phase (cake) takes place.

In this case, water and oil are sent back to the customer for recycling, and the solid phase (cake) is sent for disposal.

If the lower explosive limit is determined using a gas analyzer located on a robotic gun with a video surveillance system and lighting 5, the inert gas is automatically supplied to the tank 1 through the inert gas supply line 10 by means of an inert gas supply unit.

After completion of the removal of sediments, either the supply of the erosion agent from the robotic guns with a video surveillance system and lighting 5 to the orbital washing heads 6 is made, or the additional connection of the orbital washing heads 6 and the continuous process of finishing cleaning the roof, walls and bottom of the tank 1 begins.

The duration of the final cleaning of the tank 1 with the use of orbital washing heads 6 is about 4 hours.

After the cleaning of the tank 1 is completed, auxiliary equipment is dismantled, all technological openings are opened, including the lower technological hatches 2 and the roof hatches of the tank 13, and the tank 1 is put to natural drying for 2 hours.

Next, quality control of cleaning the tank 1 from deposits is carried out, including monitoring the functioning of the technological equipment of the tank 1, checking the tightness of lines and communications, monitoring the gas pollution of the air inside and outside the tank 1, visual monitoring the quality of cleaning the tank from deposits and the quality of cleaning the roof, walls and bottom reservoir 1.

The purity of the internal surfaces and the state of the air inside the tank 1 at the end of the processing process is evaluated depending on the purpose of cleaning and subsequent work.

The following are examples of specific performance, the results of which are shown in the table.

Example 1

The cleaning of the reservoir with a volume of 5000 m ³ and a scale of 621 m ^{3 was} carried out at an ambient temperature of 21 ° C.

Deposits were cleaned using two robotic guns with a video surveillance system and lighting 5 installed in the lower technological hatches 2 of tank 1.

As a washing agent used industrial water with a temperature of 80 ° C.

The erosion of deposits was carried out through robotic guns with a video surveillance system and lighting 5 under a pressure of 2.0 MPa.

The removal of liquefied sediments was carried out by means of two pumps 4 mounted on self-moving units with remote control.

The quality of sediment erosion and their subsequent removal was remotely controlled by the operator through a video surveillance system.

Finishing washing was carried out for 4 hours using orbital washing heads 6 located in the hatches of the roof of the tank 13, under a pressure of 2.0 MPa, at a water temperature of 80 ° C.

Example 2

The cleaning of the tank with a volume of 2000 m ³ and a scale of 312.5 m ^{3 was} carried out at an ambient temperature of 15 ° C.

The deposits were cleaned using two robotic guns with a video surveillance system and lighting 5, one of which was installed in one of the lower technological hatches 2 of tank 1, and the other on a self-moving unit with remote control.

As a washing agent, a salt solution based on calcium chloride with a temperature of 90 ° C was used.

The erosion of deposits was carried out through robotic guns with a video surveillance system and lighting 5 under a pressure of 1.5 MPa.

The removal of liquefied sediments was carried out by means of two pumps 4 mounted on self-moving units with remote control.

The quality of sediment erosion and their subsequent removal was remotely controlled by the operator through a video surveillance system.

Finishing washing was carried out for 4 hours using orbital washing heads 6 located on the roof of the tank 1, under a pressure of 1.5 MPa, at a temperature of saline solution of 90 ° C.

Example 3

The cleaning of the tank with a volume of 20,000 m ³ and a sediment value of 399.2 m ^{3 was} carried out at an ambient temperature of 10 ° C.

The deposits were cleaned using three robotic guns with a video surveillance system and lighting 5, one of which was installed in one of the lower technological hatches 2 of tank 1, the other on a self-propelled unit with remote control, the third on a tripod in the middle of the bottom of tank 1.

A solution based on diesel fuel with a temperature of 120 ° C was used as a washing agent.

The erosion of deposits was carried out through robotic guns with a video surveillance system and lighting 5 under a pressure of 1.0 MPa.

The removal of liquefied sediments was carried out by means of two pumps 4 mounted on self-moving units with remote control.

The quality of sediment erosion and their subsequent removal was remotely controlled by the operator through a video surveillance system.

Finishing washing was carried out for 4 hours using orbital washing heads 6 located on the roof of the tank 1, under a pressure of 1.5 MPa, at a temperature of the erosion agent of 120 ° C.

The application of the claimed cleaning method allows you to:

- carry out work on cleaning tanks from deposits in a continuous mode;

- significantly reduce the cleaning time (because the technological process occurs in a continuous mode: mechanized cleaning of the tanks from deposits, then the process of washing the roof, walls and bottom), reduce energy and material costs for cleaning the tanks;

- reduce the amount of waste generated, reduce the cost of disposal of waste resulting from the cleaning of tanks;

- receive income from the sales of products extracted from sediments by extracting commercial grade oil from sediments;

- eliminate the likelihood of emergency situations (fires, explosions, poisoning of people, environmental pollution) and ensure industrial and environmental safety;

- improve the quality of cleaning the tank, which allows diagnostics, repairs using hot work inside the tank.

The proposed method allows you to work remotely in an automatic mode, without the presence of a person in the tank or near the tank, during the removal of deposits and washing the tank, without the risk of harm to both the equipment used and the maintenance staff, since during the work people are not in the tank .

Claims (1)

The method of cleaning tanks intended for storage and transportation of oil and oil products, including the supply of a scouring agent, liquefaction and mixing of sediments, removal and transportation of liquefied sediments to the processing stage, while washing, liquefying and mixing of sediments is carried out using a remotely controlled robotic gun, permanently installed inside the tank through the lower technological hatches, the removal of liquefied sediments is carried out by pumps, also placed inside l the tank through the lower technological hatches, washing and mixing is carried out with a hot washing agent under a given pressure, after which the roof, walls, bottom of the tank are washed by means of orbital washing heads, to which the washing agent is switched, and if the lower explosive limit is exceeded, they are automatically fed inert gas into the tank, characterized in that the erosion, dilution and mixing of the deposits is carried out after sealing the lower technological hatches and of the roof of the tank using one or more remotely controlled robotic guns with a video surveillance system and lighting, remotely monitoring the erosion quality through a video surveillance system, pumps that discharge liquid deposits, the quality of which is also remotely controlled by a video surveillance system, is installed on explosion-proof hydraulic versions driven self-propelled units with remote control, placed inside the tank Without lower technological hatches and made with the possibility of placing robotic guns on them with a video surveillance system and lighting, orbital washing heads, the body of which is made of stainless steel and by means of which the roof, walls and bottom of the tank are washed, are placed in the tank roof hatches, while the robotic guns with video surveillance system and lighting are also installed in the lower technological hatch and / or on a self-moving unit with remote control, the temperature is eroded th agent selected in the range up to 310 ° C, depending on the ambient temperature, and its pressure is from 1.0 to 2.0 MPa.

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