RU2775217C1 - Fire extinguishing installation in tanks using internal ring foam lines and thermal fire detectors - Google Patents

Abstract

FIELD: fire protection.

SUBSTANCE: invention relates to means of fire extinguishing in petroleum products and can be used in the oil industry to extinguish fires of petroleum products in vertical steel tanks of large capacity. The fire extinguishing installation in tanks using internal annular foam lines and thermal fire detectors contains the main foam line, the upper inner annular foam line, the outer annular foam line, sections of foam line, foam nozzles, foam generator, check and solenoid valves, starting device. The tank is additionally equipped with lower and middle inner annular foam lines with four foam nozzles on each, respectively, while the main foam line is connected to the lower inner annular foam line, and the lower inner annular foam line is connected to the middle inner annular foam line with the help of a section of foam line, foam nozzles are placed evenly on the sections of the lower and middle inner annular foam lines with a turn in the vertical projections at 45 degrees relative to each other, and two additional technological hatches with thermal fire detectors are installed on the roof of the tank, while the fire detectors are connected by communication lines to relays, video and audio signals.

EFFECT: simultaneously feeding foam into the tank through the lower, middle and upper annular foam lines using foam nozzles and foam chambers, as well as through an external annular foam line using foam chambers for tank bunding, while significantly reducing the time of foam lifting into the burning layer of petroleum product and reducing the time for extinguishing, as well as by using thermal fire detectors, relays, video and audio signals the time to determine the start of a fire is minimized.

1 cl, 3 dwg

Description

SUBSTANCE: proposed invention relates to means for extinguishing oil products, and can be applied in the oil industry to extinguish fires of oil products in vertical steel tanks (RVS) of large capacity from 5000 to 50000 m ³ .

The present invention is most applicable in extinguishing fires of petroleum products at oil depots and fuel depots in tanks for long-term storage of petroleum products. Long-term storage tanks are filled according to the level of maximum capacity.

In accordance with the requirements, ground tanks for storing oil and oil products with a volume of 5000 m ³ or more are equipped with fire extinguishing systems. In warehouses of the third category, if there are no more than two ground tanks with a volume of 5000 m ^3, it is allowed to extinguish these tanks with mobile fire equipment. Provided that the tanks are equipped with permanently installed foam generators (foam chambers, foam nozzles) and special pipelines brought out beyond the embankment [Guidelines for extinguishing oil and oil products in tanks and tank farms. - M. GUGPS, 1999]. Extinguishing fires in tanks can be done in two ways:

1. Supply of medium and low expansion foam from the top of the tank to the layer of burning oil product.

2. Supply of low expansion foam under the oil product layer.

There are cases of fire inside the embankment. This fire can lead to the following types of emergencies:

1. Heating of oil and oil products with subsequent explosion of fuel in the tank.

2. Heating of oil and oil products with subsequent combustion of fuel in the tank.

3. Volumetric explosion of a vapor-air cloud that emerged from the reservoir in the atmosphere.

4. Downwind drift of a vapor cloud from a reservoir in the atmosphere with or without a possible subsequent explosion.

Installations for extinguishing fires with medium and low expansion foam on top of the tank on the oil product layer in most cases do not provide fire extinguishing at the initial stage due to damage to the foam injection units from the primary explosion.

Known vertical steel tank for oil and oil products with a volume of 5000 m ³ equipped with subsurface quenching [Sharovarnikov A.F. and others. Putting out fires of oil and oil products: second edition, Fire science 2007]. Installation of subsurface extinguishing of tanks contains a foam line with wiring, valves, a foam generator, a safety membrane, a check valve. The foam jet, getting into the oil product, floats to the burning surface due to its lower density. In this case, the time of foam rise depends on the height of the level of oil and oil products. The height of the tank with a capacity of 5000 m ³ , depending on the diameter, is from 12 to 15 meters. The disadvantages of installing under-layer quenching of oil products in tanks are:

1. Deterioration of the quality of petroleum products when passing through their layer of foam jet.

2. The presence of a certain time period of foam rising to the surface of the oil product, which leads to an increase in the fire area and an increase in material damage.

3. Inability to extinguish oil and oil products in case of fire inside the tank bund.

Also known installation for layer-by-layer extinguishing of oil and oil products in tanks containing water [Matveev Yu.A. etc. Utility model patent No. 84544 dated 10.07. 2009].

The installation includes a foam line equipped with valves, a check valve, a safety membrane and a foam generator.

A set of telescopic retractable pipes of various diameters, fixed on a floating plate, is vertically installed at the end of the foam pipe. The upper pipe of the kit is equipped with wiring and foam nozzles. In order to fix and seal the pipes during extension, the set is equipped with holders and sealing rings, and a check valve is installed on the wiring to prevent oil from entering the pipes. The unit is equipped on a vertical steel tank, including internal sectional heaters.

The installation works as follows. Oil enters the tank through the inlet pipe, pipeline and corresponding valve. With the help of internal heaters, hot steam is supplied to the RVS. A layer of water and a layer of oil are formed in the reservoir. When oil or oil product ignites, the foaming agent solution is fed into the reservoir using a stationary source or a mobile tank truck. At the same time, the valves, the non-return valve of the foam line open, and the membrane is activated under pressure. The foaming agent solution passes through the steam generator and enters the set of retractable pipes and wiring. After that, the check valve opens, and the foam jet through the foam nozzles enters the upper layer of oil (oil product). Then, due to the lower density, the foam jet reaches the surface of the oil product and forms a foam layer. As a result of the formation of a layer of foam and the termination of access to oxygen in the air, the fire stops. The disadvantages of the installation for layer-by-layer extinguishing of oil and oil products in tanks containing water are:

1. A large number of telescopic tubes that can lose mobility during operation.

2. The presence of a safety membrane, which may lose its properties during operation and requires replacement after extinguishing or testing the installation.

3. Possibility of oil (petroleum product) getting into telescopic pipes through sealing rings between pipes.

4. Inability to extinguish oil and oil products in case of fire inside the tank bund.

It is also known to install subsurface quenching for oil and high-viscosity oil products [Matveev Yu.A. and others. Patent for utility model No. 99716 dated 27.11. 2010].

The installation includes a foam pipeline equipped with gate valves, a check valve, an electromagnetic valve with a starting device and a foam generator. At the end of the foam line, a support pipe is installed vertically, led down behind the bottom of the tank, into which a movable pipe is hermetically inserted, fixed on a floating plate and equipped with wiring and foam nozzles. For the purpose of fixation and tightness, when extending the pipes, they are equipped with holders and sealing rings, and to prevent the ingress of oil into the pipes, a check valve is installed on the wiring.

Installation of subsurface quenching for oil and high-viscosity oil products operates as follows. Oil or oil product enters the tank through the inlet pipe, pipeline and the corresponding valve. A layer of oil (petroleum product) is formed in the reservoir. When the fuel and lubricant ignites, the foaming agent solution is fed into the reservoir using a stationary source or a mobile tank truck. At the same time, the valves, the check valve, the foam line solenoid valve open. The foaming agent solution passes through the foam generator and enters the moving pipe and wiring. After that, the check valve opens, and the foam jet through the foam nozzles enters the upper layer of oil (oil product). Then, due to the lower density, the foam jet reaches the surface of the fuel and lubricant and forms a layer of foam on the surface of the burning oil product. As a result of the formation of a layer of foam and the termination of access to oxygen in the air, the fire stops.

In case of high temperature, smoke and the inability of the operator to work near the tank, the solenoid valve is opened by an electric motor. To do this, the operator turns on the starting device. After extinguishing the fire and carrying out preventive maintenance, the foam pipeline will not require repairs associated with the replacement of the membrane.

The disadvantages of the installation of layer-by-layer extinguishing for oil and high-viscosity oil products are:

1. The presence of two retractable pipes, which can lose mobility during operation.

2. The exit of the lower pipe beyond the bottom of the tank, which leads to a change in the design of the bottom and additional welded joints.

3. Inability to extinguish oil and oil products in case of fire inside the tank bund.

4. Absence of a valve of increased productivity for the release of a vapor-air mixture when heating oil and oil products in a tank from a fire in a bunding or in a VST.

It is also known to install under-layer quenching of oil products with a floating plate moving vertically along the support pipe [Matveev Yu.A. and others. Patent for utility model No. 120696 dated 27.09.2012].

This installation consists of a floating plate that moves vertically along the support pipe by changing the fuel level. Piping with foam nozzles is rigidly mounted to the floating plate. Connected to the piping is a metal flexible sleeve, which is connected to a foam line inside the tank. The floating plate is mounted on a stationary support pipe connected to the top and bottom of the tank due to an internal hole. The foam line is equipped with a foam generator, valves and a check valve.

The installation works as follows. Through the inlet pipe, pipeline and the corresponding valve, the oil product enters the tank. A layer of oil product is formed in the tank. When a combustible ignites, the foaming agent solution is fed into the reservoir using a stationary source or a mobile tank truck. At the same time, the valves, the check valve, the foam line solenoid valve open. The foaming agent solution passes through the foam generator and enters the metal flexible hose, pipeline and wiring. After that, the check valve opens, and the foam jet through the foam nozzles enters the upper layer of the oil product. Then, due to the lower density, the foam jet reaches the surface of the fuel and forms a layer of foam above the level of the burning oil product. As a result of the formation of a layer of foam and the cessation of access to air oxygen, the fire stops.

The disadvantages of installing under-layer quenching of oil products with a floating plate moving vertically along the support pipe are:

1. Lack of the possibility of extinguishing oil and oil products in case of fire inside the tank bund.

2. Lack of the possibility of extinguishing with the supply of foam from the bottom and top of the tank.

3. Absence of a valve of increased productivity for ejection of the steam-air mixture during heating of oil and oil products in the tank from a fire in the dike or in the adjacent RVS.

4. The absence of a device that allows you to determine the beginning of a fire.

The closest in technical essence of the invention is the installation of extinguishing fires in vertical steel tanks and their bunding with a device to prevent an explosion when the oil product is heated [Matveev Yu.A. and others. Patent for utility model No. 134057 dated November 10, 2013].

The vertical steel tank has a suction pipe and a pipeline, valves, a breathing valve, light and gauge hatches, a ventilation pipe, a manhole, dike.

A foam pipeline is connected to the tank, equipped with valves, a check valve, a solenoid valve, with a manual opening and closing device, as well as a foam generator. The solenoid valve is connected by a communication line to the starting device.

The foam line is rigidly connected by a metal flexible hose to the distribution pipeline with a check valve and foam nozzles. The wiring is connected to a floating plate, which is mounted on a stationary support pipe connected to the roof and bottom of the tank. Check valves are designed to prevent oil from entering the wiring, flexible metal hose and foam line.

The floating plate moves vertically in the upper layer of the oil product through the pipe due to changes in the fuel level in the tank.

In order to strengthen the tank structure, the support pipe is rigidly connected by trusses to the side walls of the tank.

Sections of foam pipelines are connected to the foam pipeline. The first section of the foam line is rigidly connected to the annular inner foam line with upper foam nozzles (foam chambers). This section of the foam line is equipped with a solenoid valve. The second section of the foam line is connected to an annular external foam line with lower foam nozzles (foam chambers). This section of the foam line is also equipped with a solenoid valve. In order to prevent the explosion of fuel in the tank and reduce the pressure of the vapor-air mixture from heating by the fire of the flame in the dike or the adjacent VST, the tank is equipped with an additional breathing valve of increased productivity.

The installation works as follows. Through the inlet pipe, pipeline and the corresponding valve, the oil product enters the tank. A layer of oil product is formed in the tank. When a combustible ignites, the foaming agent solution is fed into the reservoir using a stationary source or a mobile tank truck. At the same time, the valves, the check valve, the foam line solenoid valve open. The foaming agent solution passes through the foam generator and enters the metal flexible hose, pipeline and wiring. After that, the corresponding check valve opens, and the foam stream through the foam nozzles enters the upper layer of the oil product. Then, due to the lower density, the foam jet reaches the surface of the fuel and forms a layer of foam above the level of the burning oil product.

At the same time, through the first section of the foam line, the solenoid valve, the foam is fed into the annular internal foam line and through the upper foam nozzles (foam chambers) enters the tank.

As a result of the formation of a layer of foam and the termination of access to oxygen in the air, the fire stops.

Also, simultaneously through the second section of the foam line, the solenoid valve, the foam is fed into the annular external foam line and through the lower foam nozzles (foam chambers) enters the dike.

In case of high temperature, smoke and the inability of the operator to work near the tank, the solenoid valves open with the help of an electric motor. To do this, the operator turns on the starting device.

In the event of a fire in the bunding or in the adjacent RVS and heating of the fuel in the tank, the pressure of the vapor-air mixture will increase significantly. In this case, the steam-air mixture will exit through the breathing valve and the breathing valve of increased productivity, thereby preventing the explosion of the heated oil product in the tank and the destruction of the RVS.

In case of fire in the embankment, the operator can only open the solenoid valve of the pipeline section connected to the external foam pipeline.

The disadvantages of installing fire extinguishing in vertical steel tanks and their dikes with a device to prevent an explosion when the oil product is heated are:

1. The absence of a device that allows you to determine the beginning of a fire.

2. The probability of failure of the metal flexible hose. The high complexity of repairing a metal flexible hose associated with the release of oil from the tank.

3. The presence of a certain service life of a metal flexible hose, after which its replacement is required.

4. The probability of failure of the floating plate associated with the loss of movement through the pipe. The probability of a spark occurring when a metal floating plate moves horizontally along a metal pipe. High fire hazard of the installation.

Tank farms of oil depots, fuel depots occupy large areas and are sometimes located at considerable distances from the locations of operators, storekeepers, security guards and other categories of oil depot workers. In the considered technical devices, there are no devices for detecting the start of a fire. Therefore, fires in tank farms are determined mainly visually and with the help of noise signals (explosions). In this case, the time for determining the start of a fire, especially at night, can be from 5 to 40 minutes or more.

The present invention makes it possible to solve the problem of increasing the efficiency of extinguishing fires inside large-capacity vertical steel tanks, as well as in the dike around these tanks. This minimizes the time to determine the start of a fire.

The solution to this problem is achieved by the fact that the tank is equipped with lower and middle inner annular foam pipelines with four foam nozzles on each foam pipeline, respectively, two additional technological hatches with heat fire detectors are installed on the roof of the tank, while fire detectors are connected by communication lines to relays, video and sound signals, as well as the fact that the main foam duct is connected to the lower inner annular foam duct, while the lower inner annular foam duct is connected to the middle inner annular foam duct using a section of the foam duct, it should be noted that the foam nozzles are placed evenly on the sections of the lower and middle inner annular foam ducts with a rotation in vertical projection by 45 degrees relative to each other, as well as the fact that when one thermal fire detector is triggered, the video signal is turned on, and then when the second thermal fire detector is triggered, the audio signal is turned on drove.

These features are essential for solving the problem of the invention, since the efficiency of extinguishing oil products in a large-capacity RVS, as well as in bunding, increases the reliability of the installation, minimizes the time for detecting the onset of a fire, reduces the time for fire extinguishing and the likelihood of a fuel explosion in a tank heated by a fire in a fire. collapse or flames of an adjacent reservoir.

The essence of the utility model is illustrated by drawings (Fig. 1, Fig. 2, Fig. 3), which show: a section of a tank with a dike, a top view of the lower and middle internal annular foam pipes with foam nozzles, as well as sections of technological hatches with thermal fire detectors, which are connected to relays, video and audio signals.

In FIG. 1 shows a tank 1 having an inlet pipe 2 and a pipeline 3, a valve 4, a breathing valve 5, light and measuring hatches 6,7, a ventilation pipe 8, a manhole 9, an embankment 10, a main foam pipeline 11, equipped with a check valve 12, electromagnetic valve 13, membrane 14, communication line 15 and starting device 16, as well as foam generator 17.

The main foam pipeline 11 is rigidly connected to the lower annular foam pipeline 18 and the upper annular foam pipeline 19. The lower annular foam pipeline 18 is equipped with four foam nozzles 20, which are under the oil layer 21. The upper annular foam pipeline 19 is equipped with foam chambers 22. The lower annular foam pipeline is connected using the foam pipeline section 23 with an average annular foam pipeline 24, which is equipped with four foam nozzles 20. In order to release foam throughout the volume of the tank, the foam nozzles are placed evenly on the sections of the lower and middle annular foam pipelines with a rotation in a vertical projection of 45 degrees relative to each other.

A section of the foam line 25 is connected to the main foam line 1 1, which is rigidly connected to the annular external foam line 26 with foam chambers 22. This section of the foam line 25 is equipped with a solenoid valve 13, which is connected by a communication line to a separate starter 27.

Also, the tank 1 is additionally equipped with two technological hatches 28, which are not connected with the vapor space of the tank.

A thermal fire detector 29 is installed in each technological hatch, which is connected by communication lines 15 to relay 30. The relay is connected by communication lines to video signal 31 and sound signal 32. Fire detector 29 is attached to the inside of the technological hatch cover. To ensure explosion safety and tightness, communication lines 15 are placed in the cable channel 33. Installing thermal fire detectors inside the tank can lead to the following problems:

1. Explosion of the vapor-air mixture from a short circuit in the detector.

2. The complexity of repair, replacement and maintenance of detectors.

3. Reducing tightness and increasing volatility in the tank, due to extra extra holes.

The occurrence of a fire of an oil product in a VST is most likely on one of the sections of the liquid surface. Then, due to the linear propagation velocity, the flame is distributed over the entire surface of the oil product. Therefore, heat detectors will not heat up evenly and may operate up to several minutes apart.

In order to prevent an explosion of the oil product in the tank and reduce the pressure of the vapor-air mixture (SVA) 34 from being heated by the fire of the flame in the dike or the adjacent VST, the tank is equipped with an additional high-capacity breathing valve 35.

The invention works as follows. Through the inlet pipe 2, the pipeline 3 and the corresponding valve 4, the oil product enters the tank. A layer of oil product 21 is formed in the tank.

When an oil product ignites, the roof of the tank and technological hatches 28 with thermal fire detectors 29 are heated. When the temperature in the technological hatches reaches 65 ° C and above, fire detectors 29 are activated, which, through the communication lines 15, turn on the relay 30 and the corresponding video signal 31 and the sound signal 32. It should be noted that when one detector 29 is triggered, the video signal 31 is turned on, and then when the second thermal fire detector is triggered, the sound signal 32 is turned on. If only one video signal is triggered, the operator takes measures to visually determine the occurrence of a fire. After establishing the fact of ignition of oil products, the operator turns on the starting device 16.

When an audible signal is sounded when two fire detectors are triggered, the operator turns on the starting device 16 and the foam concentrate solution is fed into tank 1 with the help of a pump. At the same time, the check valve 12, the solenoid valve 13 of the main foam line 11 are opened. The foam concentrate solution passes the foam generator 17, breaks the membrane 14 and enters the lower annular foam pipeline 18, the upper annular foam pipeline 19 and through the section of the foam pipeline 23 into the middle annular foam pipeline. The foam jet through the foam nozzles 18 of the lower and middle annular foam pipelines enters the oil product layer 21. Then, due to the lower density, the foam jet reaches the surface of the oil product and forms a foam layer. The exit of the foam through the foam nozzles of the middle annular foam line 24 makes it possible to reduce the time of foam lifting and reduce the time to extinguish the fire.

At the same time, through the upper annular foam line 19 and the foam chamber 22, the foam enters the upper part of the tank 1.

As a result of the formation of a layer of foam and the termination of access to oxygen in the air, the fire stops.

In the event of a fire, there is a possibility of failure of the foam chambers 22 and the upper annular foam line 19 as a result of an explosion of the vapor-air mixture 34 in the tank. In this case, the fire will be extinguished by supplying foam to the lower and middle annular foam lines.

When a burning oil product enters the embankment 10 of the tank 1 through the section of the foam pipeline 25, the corresponding solenoid valve 13, which is opened using the starting device 27, the foam is fed into the outer annular foam pipeline 26. Then, through the foam chambers 22, the foam enters the embankment.

In the event of a fire directly in the bunding 10 or in the adjacent RVS and heating of the fuel in the tank, the pressure of the vapor-air mixture 34 will increase significantly. In this case, the steam-air mixture will exit through the breather valve 5 and the breather valve of increased productivity 35, thereby preventing the explosion of PVA and heated oil in the tank and the destruction of the RVS. In case of fire in the embankment, the operator can only open the solenoid valve of the foam line section 27 connected to the outer annular foam line 26.

It should be noted that the proposed invention is reliable in operation and allows you to put out the fire in a shorter time, both in the tank and in the bunding, to minimize the likelihood of a fuel explosion in the tank, associated with an increase in the temperature of the oil product from a fire in the bunding or from exposure to thermal the flow of a burning adjacent tank.

At the same time, the invention makes it possible to determine the onset of a fire in the shortest possible time and minimize the loss of an oil product, as well as reduce the time to extinguish a fire.

Claims (2)

1. Installation of fire extinguishing in tanks using internal annular foam pipelines and thermal fire detectors, containing the main foam pipeline, the upper internal annular foam pipeline, the external annular foam pipeline, sections of the foam pipeline, foam nozzles, a foam generator, a check and electromagnetic valves, a starting device, characterized in that the tank is additionally equipped with lower and middle inner annular foam ducts with four foam nozzles each, respectively, while the main foam duct is connected to the lower inner annular foam duct, and the lower inner annular foam duct is connected to the middle inner annular foam duct using a section of the foam duct, foam nozzles are placed evenly on the sections lower and middle internal annular foam pipelines with a rotation in vertical projection by 45 degrees relative to each other, and two additional technological hatches with thermal fire alarms are installed on the roof of the tank at the same time, fire detectors are connected by communication lines to relays, video and sound signals. 2. Installation according to claim 1, characterized in that when one thermal fire detector is triggered, a video signal is turned on, and then when the second thermal fire detector is triggered, an audio signal is turned on.

Images