RU2225731C2 - Method of conflagrant petroleum volumetric extinguishing inside a furnace of petroleum heating and installation for its realization - Google Patents

Abstract

FIELD: fire extinguishing. SUBSTANCE: the invention presents a method of conflagrant petroleum volumetric extinguishing inside a furnace for its heating and an installation for its realization. The invention is dealt with the fire extinguishing engineering and may be used for the conflagrant petroleum extinguishing inside the furnace for its heating. The method of the conflagrant petroleum volumetric extinguishing inside the furnace for its heating provides for to use in the capacity of the fire extinguishing substance a fluid carbon dioxide, feeding of which into the furnace for petroleum heating is exercised stepwise: in the beginning - up to the extinguishment of the petroleum fire, then with a time-delay the second batch of a fluid carbon dioxide is fed till the temperature in the furnace for heating drops below the temperature of the petroleum inflammation. The installation for conflagrant petroleum volumetric extinguishing inside the furnace for petroleum heating has: a container with a fire extinguishing substance, that is linked by pipe lines with the furnace for petroleum heating; refrigerating units linked with the container, in which the heating elements are installed, that are connected with the control cabinet, that has a weighting terminal and is connected through a shut-off device with the container and with atomizers mounted in the furnace for heating petroleum. At that the control cabinet is also connected to the acceptance - control and fire prevention console, that is in turn connected to the dispatcher control panel and the console of remote start-up. The chimney flues of the furnace for petroleum heating have the pipes blanking devices installed in them and containing the pneumatic valves connected through the pulse pipelines with a starting gas bottle connected to the acceptance - control and fire prevention console, that in turn is connected with the pipeline shut-off valves of the device for blanking pipes and with the manual fire alarm announcer installed in a safe zone near the petroleum heating furnace. The technical result from use of the invention is decrease of a risk of explosion in case of an emergency petroleum spill out inside the furnace for petroleum heating, increase of reliability of fire-extinguishing and decrease of its cost. EFFECT: decreased risk of explosion of an emergency petroleum spill out inside the furnace for petroleum heating, increased reliability of fire- extinguishing and decreased its cost. 2 cl, 1 dwg _

Description

The invention relates to fire fighting equipment and can be used to extinguish burning oil inside a furnace for heating it.

Crude oil is heated to a temperature of 200-250 ° C in heating furnaces before being launched into a distillation distillation column (Technological regulations and operating instructions PB-20.00.00.000.TO).

By design, furnaces of this type are narrow-chamber furnaces with an upper flue gas outlet, a central horizontal screen and radiating walls from flameless panel burners. Oil enters the upper pipes of the heat exchanger of the convection chamber and, leaving the lower pipes of this chamber, enters the radiation chamber. Fuel gas enters the panel burners, assembled in two walls, located opposite each other, which provides two-sided irradiation of the heat exchanger.

Under operating conditions, leaked oil may leak inside the furnace due to burnout and the formation of cracks or fistulas on the surface of the heat exchanger tubes. The most dangerous accident may be a complete depressurization of the heat exchanger tubes, as a result of which a significant amount of oil can enter the interior of the furnace. The danger of explosion, cotton, and depressurization of the pipeline and oil spill is associated with the presence inside the furnace of the surface of the heat exchanger tubes and internal surfaces of the furnace structure heated above the temperature of auto-ignition of oil vapor. The lowest value of the auto-ignition temperature of vapors for mineral oil, which is part of the oil, is 230-235 ° C. Handbook "Fire hazard of substances and materials" .- M.: Chemistry. T.1, 2. 1991.

A known method of extinguishing a fire of flammable liquids, including the supply and spraying of liquid freon (Baratov AN, etc. Fire extinguishing at enterprises of the chemical, petrochemical and oil refining industries. - M .: Chemistry, 1971, p.363).

The disadvantage of this method is that at high temperatures freons are able to decompose with the release of toxic substances.

A known method of extinguishing a fire using carbon dioxide (AS USSR No. 1806795, class A 62 3/06, publ. 07.04.93). However, when using the known method for burning oil inside the furnace, a large building is needed to store carbon dioxide cylinders for heating it. The disadvantage is the complexity of equipment maintenance.

There is a method of extinguishing flammable liquids in a tank, which consists in feeding liquid carbon dioxide under a liquid layer (AS USSR No. 1299599, class A 62 C 3/12, publ. 30.03.87). However, for extinguishing burning oil inside the furnace for heating it, the method is ineffective due to the insignificant height of the layer of spilled oil and its ingress on the surface of the enclosing structures of the furnace and heat exchangers.

The closest to the claimed technical essence and the achieved result, selected as a prototype, is a method of extinguishing burning oil inside a furnace for heating it, in which steam is used as a fire extinguishing composition (Instruction for designing steam protection of technological furnaces at oil refining and petrochemical enterprises. Approved by the Ministry of the oil refining and petrochemical industry and agreed with the Main Directorate of the State Fire Service of the USSR Ministry of Internal Affairs, 1976).

Installation for implementing this method includes a boiler room or a heat point, steam pipelines (direct and reverse), valves.

The disadvantage of this method and installation is the lack of efficiency and the high cost of fire extinguishing, since during the non-heating season for the needs of fire fighting it is necessary to keep the boiler room in operation.

The problem solved by the invention is the creation of an effective, economical method and installation for extinguishing oil burning inside the furnace.

The technical result from the use of the invention is to reduce the risk of explosion during an emergency spill of oil inside the furnace for heating, increasing the reliability of fire fighting and reducing its cost.

This result is achieved by the fact that in the method of volume quenching of burning oil inside the furnace to heat it with a fire extinguishing agent, liquid carbon dioxide is used as a fire extinguishing agent, which is supplied in stages to the oil heating furnace, first, before the oil is stopped burning, then with a time delay serves a second portion of liquid carbon dioxide to lower the temperature in the furnace to heat below the flash point of the oil.

The indicated result is also achieved by the fact that the installation for volumetric extinguishing of burning oil inside the furnace for heating it, containing a reservoir with a fire extinguishing agent, connected by pipelines to the furnace for heating oil, is equipped with refrigeration units connected to a tank in which heating elements are connected to the cabinet control, containing a weighing terminal and connected through a locking-starting device with a tank and with sprayers installed in the furnace for heating oil, while the control cabinet The unit is also connected to a control panel for a fire and security start-up, connected to a dispatcher and a remote start, in the chimneys of an oil heating furnace, devices for blocking pipes are installed, containing pneumatic valves connected via pulse pipelines to a starting gas cylinder connected to the panel security control and fire starting, which in turn is connected to the limit switches included in the device for blocking pipes, and with a manual fire detector installed in safe area near the oil heating furnace.

Liquid carbon dioxide is a colorless, odorless liquid, non-toxic. non-explosive. When released from the storage tank, it turns into gas and snow with a temperature of -78.5 ° C

The method can be implemented using the installation shown in the drawing.

 The volumetric extinguishing apparatus for burning oil inside the furnace for heating it contains an isothermal tank 1 for liquid carbon dioxide with heating elements 2 installed in it, one of which is reserve, connected to the control cabinet 3. Two refrigeration units 4 are connected to the tank 1, one of which spare. The control cabinet 3 is connected to the tank 1 through a locking and starting device 5, which is connected by main pipelines to the atomizers b installed in the oil heating furnace 7. The control cabinet 3 is connected to the remote control 8 by a security and fire start-up control panel installed in a heated container 9 and connected to the dispatcher's control panel 10 and to the remote control remote control 11. In the furnace 7 for heating oil in chimneys 12, devices 13 are installed for blocking the pipes, containing pneumatic valves 14 connected via pulse pipelines 15 to the starting gas cylinder 16, which is connected to the control panel 8 by the security and fire-starting. The remote control 8 is also connected to the limit switches 17, and with a manual detector 18 installed in a safe area near the oil heating furnace.

Installation works as follows. The furnace operator determines the ignition of oil in the heating furnace visually by the appearance of black smoke from the chimneys 12. By means of a manual detector 18 through the remote control 8, the security control and fire launcher, he sends a fire signal to the remote control 10 to the dispatcher, who decides to extinguish the fire. First, he turns off the supply of oil and gas to the furnace for heating oil. The signal from the remote control 10 of the dispatcher is received through the remote control 8 from the security control and fire launcher to the starting gas cylinder 16. The working gas in the cylinder 16 is nitrogen, which is at a pressure of 8.0 MPa. Nitrogen through impulse tubes enters the pneumatic valves 14, which actuate the device 13 for blocking the pipes. After the chimneys overlap, the signal from the start switch 17 enters the remote control 8, which generates a signal to start the fire extinguishing system through the control cabinet 3. A start signal lasting 10 seconds is issued with a delayed start from 10 to 99 seconds. From the control cabinet 3, a signal is generated to the locking and starting device 5, which opens the access of liquid carbon dioxide from the tank 1 through the main and distribution pipelines to the atomizers 6, and then to the furnace 7 for heating oil to extinguish the fire.

A weight terminal (not shown in the drawing), installed in the control cabinet 3, controls the weight of the liquid carbon dioxide discharged and, when it is determined in a calculation way sufficient to stop burning, its flow is stopped by a signal from the control cabinet 3 to the locking and starting device 5 After 10-15 minutes of exposure, the signal from the control cabinet 3 is again fed to the locking and starting device 5 and from the tank 1, the second portion of liquid carbon dioxide is fed through the main and distribution pipelines to the atomizers 6 and gave e in the oven 7 for heating oil. The amount of incoming liquid carbon dioxide is regulated by the weight terminal in the control cabinet 3, and when its quantity is equal to the number of the first portion of liquid carbon dioxide released, sufficient to lower the temperature in the furnace 7 to heat the oil below the flash point of oil (86 ° C), its flow stops by a signal from the control cabinet 3 to the locking and starting device 5. The system of trunk and distribution pipelines is made of cold-deformed seamless steel pipes in accordance with GOST 8734-75.

The isothermal tank for liquid carbon dioxide is a horizontal double-walled cylindrical apparatus consisting of an internal vessel, thermal insulation and a casing. The vessel, inside which there is liquid carbon dioxide, is made of austenitic stainless steel grade 12X18H10T and has the following nozzles (see drawing): outlet - for the delivery of liquid carbon dioxide from the tank through the starting and starting device; liquid - for filling the tank with liquid carbon dioxide; gas - to equalize the pressure in the tank and the transport tank when filling the tank with liquid carbon dioxide and depressurizing the tank; branch pipe for installation of a rod with an electric heater, safety valves, measuring pipelines; branch pipes for connecting refrigeration units to the tank.

The nozzles are made of stainless steel grade 12X18H10T. The space between the casing and the vessel, called the heat-insulating cavity, is evacuated and filled with perlite. To maintain the temperature of liquid carbon dioxide at an ambient temperature below minus 20 ° C, two heaters are installed in the inner vessel, one of which is a backup. The electric heater is a heating section CHO-1, mounted on a pipe. Power is supplied through an electrical connector mounted in the pipe flange.

The locking and starting device consists of a flexible metal hose, a ball valve with a manual drive, a ball valve with an electric pneumatic actuator, a cylinder with a capacity of 40 l with a locking device of an electrocontact pressure gauge, a local start device and a support rack. The locking and starting device is mounted on a support stand, not rigidly connected to the tank. The metal hose is designed to minimize the error of the weighing terminal when moving the tank relative to the locking and starting device stationary on the support post caused by ambient temperature, when filling or leaving liquid carbon dioxide from the tank.

Spherical cranes are intended for storage and release of liquid carbon dioxide by means of electro-pneumatic and manual start-up. During operation of the module, the hand-operated ball valve is in the open position and closes the pipeline only during routine maintenance. The ball valve with electropneumatic actuator is in the closed position and opens only when it is necessary to supply liquid carbon dioxide to the furnace for heating oil.

To open and close the ball valve with electropneumatic actuator from an electric or mechanical impulse, there is a cylinder with a capacity of 40 l, which stores nitrogen under pressure from 5.0 to 8.0 MPa. Two refrigeration units, one of which is reserve, with the necessary equipment is designed to maintain pressure in the tank with liquid carbon dioxide. In the event of a failure of the main refrigeration unit, a standby unit is switched on. The control cabinet is a wall-mounted frame construction with a front door. Inside the cabinet there is switching and protective equipment, on the door there is a TV-003/05 D weight terminal, light indicators and switches for controlling the operation of refrigeration units and electric heaters. As distributors can be used, for example, type RU-A-80, a control panel for a security and fire start-up launcher, a remote control dispatcher, a remote start-up device kit “Poca-2SL”. A device for blocking pipes can be performed, for example, with a shield shutter with electric air start, a manual fire detector-IPR-3C. The equipment is placed in an insulated container, for example, metal.

For the successful practical application of the proposed method, it is necessary to have its reserve stock in an isothermal tank for liquid carbon dioxide in an amount equal to the number of two portions released during fire fighting, and also to maintain its pressure in the tank at least 10 bar, since at a pressure of 4.2 bar carbon dioxide from the liquid phase passes into the solid.

The consumption rate of liquid carbon dioxide (according to NPB 22-96 "Automatic gas fire extinguishing installations. Design norms and rules. - M .: GTsGPS MVD RF, 1977), taking into account the presence of various hydrocarbons in oil, including the fraction corresponding to gasoline, kerosene and of others, it is 0.7 kg / m. In addition, factors (leakage, losses due to leakage of the furnace) equal to 10% of the value of the extinguishing concentration are taken into account.The release time into the protected volume of liquid carbon dioxide is 60 seconds for a single serving. extracts (10-15 min) after the start of the first portion of liquid carbon dioxide is determined by the leakage of the building envelope of the furnace.

An example implementation of the method.

The method of volumetric extinguishing of burning oil inside the furnace for its heating was tested during the acceptance tests of the fire extinguishing system of the PB-20 furnaces for NGDU Jalilneft JSC Tatneft. The estimated mass M _{r of} liquid carbon dioxide, designed to extinguish a fire, was determined by the formula

M _p = K _{1 ·} V _p · ρ ₁ (1 + K ₂ ) ln [100 / (100-С _n )],

Vρ is the estimated volume of the furnace to be protected;

K ₁ - coefficient taking into account the leakage of extinguishing agent from the tank through leaks in valves, according to regulatory documents equal to 1.05;

K ₂ - coefficient taking into account the loss of gas composition through leaks of the enclosing structures of the furnace, equal to 15.85;

ρ ₁ - the density of the gas extinguishing composition, taking into account the height of the protected object relative to sea level, equal to 0.644 kg / m Thus, M _p = 1.05 · 441.0 · 0.644 · (1 + 15.85) ln [100 / (100-39)] = 2484 kg.

The total estimated consumption of liquid carbon dioxide will be 2484 · 3 = 7452 kg, including a working mass for two starts of 4968 kg and a reserve weight for one start of 2484 kg. The nominal mass of liquid carbon dioxide charged into the isothermal module MIZHU-10 / 2.2 is not more than 9780 kg, then the remainder of liquid carbon dioxide in the tank will be 2328 kg.

Tests have shown the high efficiency of the method, its simplicity and profitability.

The installation can be used to extinguish a fire in several furnaces for heating oil. In this case, the installation is supplemented by distribution devices for the number of furnaces installed between the oil heating furnaces and the locking and starting devices.

Thus, the proposed method and installation for volumetric extinguishing of burning oil inside the furnace for heating it allows to reduce the explosion hazard during an emergency oil spill by increasing the time for maintaining an explosion-proof concentration of liquid carbon dioxide, to increase the reliability of fire extinguishing, since filling with a fire extinguishing agent occurs more evenly, and reduce operational costs and fuel and energy resources by eliminating the use of steam.

Claims (2)

1. The method of volumetric extinguishing of burning oil inside the furnace for heating it with a fire extinguishing agent, characterized in that liquid carbon dioxide is used as a fire extinguishing agent, which is supplied in stages to the oil heating furnace, first, before the oil is stopped burning, then it is served with a time delay the second portion of liquid carbon dioxide to lower the temperature in the furnace for heating below the flash point of oil. 2. Installation for volumetric extinguishing of burning oil inside the furnace for heating it, containing a reservoir with a fire extinguishing agent, connected by pipelines to a furnace for heating oil, characterized in that it is equipped with refrigeration units connected to a tank in which heating elements are connected to the cabinet control, containing a weighing terminal and connected through a locking-starting device with a reservoir and with sprayers installed in the furnace for heating oil, while the control cabinet is also connected with a control panel for a fire alarm start-up connected to a control panel of a dispatcher and a remote start panel, chimneys for an oil heating furnace are equipped with devices for blocking pipes containing pneumatic valves connected via pulse pipelines to a gas trigger cylinder connected to a control panel security and fire launcher, connected, in turn, with travel switches included in the device for blocking pipes, and with a manual fire detector installed in a safe area lo oil heating furnace.

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