JP5100318B2 - Low flash point fuel storage system - Google Patents

Description

  The present invention relates to a low flash point fuel storage system for storing a low flash point fuel such as a waste solvent, and more particularly to supplying an inert gas to the tank in order to prevent an explosion of the tank storing the low flash point fuel. It relates to a storage system.

  Conventionally, various wastes such as waste plastics are used as a substitute for fuel in a cement manufacturing process to contribute to waste processing and to reduce the basic unit of expensive fossil fuel in cement manufacturing. In recent years, waste solvents containing acetone, gasoline, alcohols, kerosene, light oil, etc. have also been tried to be used as an alternative to fuel, further reducing fuel costs and waste disposal. It is expected as a method to realize the promotion.

  When using waste solvent as fuel, it is necessary to temporarily store the waste solvent that has been brought in, but low flash point liquids such as waste solvent are highly volatile and flammable, causing large-scale explosion accidents. Therefore, when handling it, it is necessary to pay sufficient attention, for example, to take measures against explosions. For example, Patent Document 1 discloses an explosion-proof method that monitors the oxygen concentration in a facility that uses a low flash point liquid and supplies nitrogen gas as an inert gas into the facility when the concentration exceeds a certain level. In this method, the oxygen concentration is reduced by replacing the air in the facility with nitrogen gas, thereby avoiding the risk of explosion.

Japanese Patent Application Laid-Open No. 5-245542

  According to the above explosion-proof method, since the oxygen concentration in the facility can be kept at a safe concentration, it is effective as an explosion-proof measure. However, for example, every time oxygen flows into the facility due to a leak or the like, the oxygen concentration Since it is necessary to supply a large amount of inert gas to lower the concentration, there is a problem that the consumption of the inert gas increases and the maintenance cost increases.

  Therefore, the present invention provides a low flash point fuel storage system capable of reliably avoiding the risk of explosion when storing low flash point fuel and reducing the consumption of inert gas. The purpose is to provide.

In order to achieve the above object, the present invention is a low flash point fuel storage system, a tank for storing low flash point fuel, a receiving pipe for receiving and throwing in low flash point fuel, An extraction line for extracting the low flash point fuel stored in the tank, an inert gas supply line for supplying an inert gas to the tank, and an internal pressure of the tank disposed on the inert gas supply line When the gas pressure became equal to or higher than the first set value, the inert gas supply line was closed, and the internal pressure of the tank became lower than the second set value, which was smaller than the first set value and larger than the atmospheric pressure. A supply control valve for opening the inert gas supply line and an oxygen concentration measuring means for measuring the oxygen concentration in the tank, wherein the concentration value measured by the oxygen concentration measuring means is not less than a predetermined value. When an alarm is issued, an alarm is issued and Stop receiving the fire point fuel, and characterized by performing one or more selected from low flash point extraction of stop of the fuel from the tank.

And according to the present invention, instead of adjusting the supply amount of the inert gas according to the oxygen concentration in the tank, the inert pressure is used to keep the internal pressure of the tank at a certain value greater than the atmospheric pressure. In addition to preventing oxygen from being mixed due to leakage, volatilization of the low flash point fuel can be suppressed, and the consumption of inert gas can be reduced. In addition, the supply control valve opens and closes the inert gas supply line using the first and second set values, so that the internal pressure of the tank fluctuates when a low flash point fuel is received or withdrawn. Even if it is easy to perform, it is possible to prevent frequent switching of the inert gas supply line, so that the internal pressure of the tank is reduced to a predetermined pressure value while suppressing wasteful consumption of the inert gas. Therefore, it is possible to reduce the consumption of the inert gas while preventing the danger of explosion by preventing the air from entering the tank. In addition, it is possible to alert the facility manager or the like and to stop the operation of the facility before an accident occurs, thereby further ensuring safety.

  In the low flash point fuel storage system, an atmosphere open pipe for releasing the gas in the tank to the atmosphere, a deodorizing means for deodorizing the gas flowing in the atmosphere open pipe, and the atmosphere open pipe are disposed on the atmosphere open pipe. And an air release valve that opens the air release pipe when the internal pressure of the tank is smaller than the pressure resistance of the tank and greater than or equal to a third set value that is greater than the first set value. According to this configuration, since the frequency of use of the deodorizing means can be reduced, it is possible to prolong the life of the deodorizing means and to reduce the labor and maintenance cost of replacement work.

  The low flash point fuel storage system may further include a return line for returning a part of the gas in the tank to a carrying-in means for carrying in the low flash point fuel when the low flash point fuel is received. According to this configuration, it is possible to avoid a sudden increase in the internal pressure of the tank, and it is possible to further improve safety.

  In the low flash point fuel storage system, the carrying-in means may be a tank truck.

  In the low flash point fuel storage system, the extraction conduit is connected to a cement firing facility, and the low flash point fuel stored in the tank can be supplied as cement firing fuel. It can be used as an alternative to fossil fuels in cement production.

  As described above, according to the present invention, when storing low flash point fuel, it is possible to reliably avoid the risk of explosion and to reduce the consumption of inert gas.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows an embodiment of a low flash point fuel storage system according to the present invention. This storage system 1 is roughly divided into a tank for storing low flash point fuel such as waste solvent including acetone, gasoline and the like. 2, a receiving pipe 3 that receives waste solvent from a tank truck (hereinafter referred to as “lorry car”) 11, a fuel supply pipe 4 that supplies the waste solvent in the tank 2 to the cement kiln burner 25, and an inert gas A nitrogen supply line 5 for supplying nitrogen to the tank 2, an open air line 6 for releasing the gas in the tank 2 to the atmosphere, and a gas return line for returning the gas in the tank 2 to the lorry vehicle 11. 7.

  The tank 2 is a sealed container having a pressure resistance of 20 kPa, for example, and is provided for temporarily storing low flash point fuel. Here, the low flash point fuel contains a substance having a flash point of less than 70 ° C., and contains a flammable liquid classified as a first petroleum defined by the Fire Service Law with a flash point of less than 21 ° C. Including things. In addition, the low flash point fuel is not limited to a liquid waste solvent or the like, but includes those in the state of an emulsion, a slurry, or the like. In the following description, the waste solvent is stored as a low flash point fuel.

  An oxygen concentration meter 8 that measures the oxygen concentration of the gas in the tank 2 and an alarm are generated when the concentration value of the oxygen concentration meter 8 exceeds a predetermined value (for example, 5%). An alarm device (not shown) is connected. In addition, a circulation line 9 for circulating and stirring the waste solvent and a stirring pump 10 are connected to the lower part of the tank 2 in order to prevent the waste solvent in the tank 2 from being difficult to handle due to precipitation and solidification.

  The receiving conduit 3 is a conduit for introducing the waste solvent brought from outside through the lorry vehicle 11 into the tank 2, and the waste solvent from the lorry vehicle 11 is supplied to the tank 2 on the receiving conduit 3. A receiving pump 12 that performs the above operation and a strainer 13 that removes foreign substances contained in the waste solvent are disposed.

  The fuel supply line 4 is a line for supplying the waste solvent extracted from the bottom of the tank 2 to the cement kiln burner 25 as a part of the fuel. On the fuel supply line 4, the fuel supply line 4 A valve 14 that opens and closes 4, a blow pump 15 that blows waste solvent from the tank 2 into the cement kiln burner 25, a flow meter 16 that measures the flow rate of the waste solvent that flows through the fuel supply line 4, The rotational speed control unit 17 that controls the rotational speed of the blow pump 15 according to the flow rate value, the valve 19 that opens and closes the flow path 18 between the blow pump 15 and the cement kiln burner 25, and the internal pressure of the flow path 18 are measured. And a pressure gauge 20 is disposed. Further, the fuel supply line 4 is supplied with a fuel return line 26 for returning a part of the waste solvent discharged from the blow pump 15 to the tank 2 and steam for cleaning the inside of the fuel supply line 4. A steam supply line 27 is provided in series.

  The nitrogen supply pipe 5 is a pipe for supplying the nitrogen gas generated by the nitrogen generator 28 to the tank 2, and the nitrogen gas generated by the nitrogen generator 28 is temporarily placed on the nitrogen supply pipe 5. A nitrogen tank 29 for storage, a pressure gauge 30 for measuring the internal pressure of the nitrogen tank 29, a valve 31 for opening and closing between the nitrogen generator 28 and the nitrogen tank 29, and a gas pressure at the upper part of the tank 2 are measured. A pressure gauge 32 and a supply control valve 33 that opens and closes the nitrogen supply pipe 5 are arranged.

  The supply control valve 33 is provided to keep the internal pressure of the tank 2 at a positive pressure, and to prevent oxygen from entering the tank 2 and volatilization of the waste solvent. The supply control valve 33 closes the nitrogen supply line 5 when the internal pressure in the tank 2 is equal to or higher than a first set value TP1 (for example, 18 kPa), and is smaller than the first set value TP1 (18 kPa), The nitrogen supply line 5 is configured to be opened when the second set value TP2 (for example, 13 kPa) or less, which is greater than the atmospheric pressure, is reached.

  The atmosphere open pipe 6 is a pipe for releasing a part of the gas in the tank 2 into the atmosphere. On the atmosphere open pipe 6, the odor component from the gas flowing in the atmosphere open pipe 6 is provided. And a breathing valve (breather valve) 35 that opens and closes the atmosphere opening pipe 6. The breathing valve 35 is provided to prevent the internal pressure of the tank 2 from becoming larger than the withstand pressure of the tank 2, and when the internal pressure of the tank 2 becomes a third set value TP3 (for example, 18 kPa) or higher, The open pipe 6 is configured to be opened. The third set value TP3 (18 kPa) is smaller than the pressure resistance of the tank 2 and is set to a value equal to or greater than the first set value TP1 (18 kPa) of the supply control valve 33.

  The gas return line 7 is a line for returning a part of the gas in the tank 2 to the lorry wheel 11 when the waste solvent is received. The gas return line 7 is provided on the gas return line 7. A pressure gauge 36 for measuring the internal pressure of the gas and a valve 37 for opening and closing the gas feedback line 7 are arranged. In FIG. 1, the gas return line 7 is connected to the atmosphere open line 6, but the gas return line 7 may be directly connected to the upper part of the tank 2.

  Next, operation | movement of the storage system 1 which has the said structure is demonstrated, referring FIG.

  When the waste solvent is brought in by the lorry wheel 11, the receiving pipe 3 and the gas return line 7 are connected to the lorry wheel 11, and the receiving pump 12 is driven to start charging the waste solvent into the tank 2. At this time, if the internal pressure of the tank 2 is equal to or lower than the second set value TP2 (13 kPa), the supply control valve 33 is driven to open, the nitrogen supply pipe 5 is opened, and nitrogen gas is supplied to the tank 2 to supply the tank. 2 is pressurized.

  At the same time, the valve 37 is driven to open and a part of the gas in the tank 2 is returned to the lorry wheel 11 through the gas return line 7 to avoid the internal pressure of the tank 2 from rapidly rising. However, when the internal pressure of the lorry wheel 11 rises to near the pressure resistance of the lorry wheel 11, the valve 37 is driven to close and the gas return line 7 is closed to avoid damage to the lorry wheel 11. When returning the gas in the tank 2, nitrogen gas is supplied to the tank 2 through the nitrogen supply pipe 5, so that the main component of the return gas to the lorry wheel 11 is nitrogen. For this reason, it is possible to avoid an increase in the oxygen concentration in the lorry wheel 11 and to ensure safety.

  Thereafter, as the storage amount of the waste solvent increases, the internal pressure of the tank 2 rises, and when it reaches or exceeds the first set value TP1 (18 kPa), the supply control valve 33 is driven to close and the nitrogen supply line 5 is connected. Close and stop supplying nitrogen gas. Note that, once the supply control valve 33 is driven to close, the supply control valve 33 maintains that state until the internal pressure of the tank 2 becomes equal to or lower than the second set value TP2 (13 kPa).

  Then, when the internal pressure of the tank 2 further rises and becomes equal to or higher than the third set value TP3 (18 kPa), the breathing valve 35 is driven to open, and the atmosphere opening conduit 6 is opened, and the gas in the tank 2 is discharged. Tank 2 is depressurized. The gas discharged from the tank 2 is deodorized by the deodorizer 34 and then released into the atmosphere.

  Thereafter, the opening and closing of the breathing valve 35 is switched depending on whether or not the internal pressure of the tank 2 becomes equal to or higher than the third set value TP3 (18 kPa), whereby the internal pressure of the tank 2 becomes equal to or higher than a predetermined pressure value. Maintained. Accordingly, it is possible to prevent the atmosphere from flowing into the tank 2 and increase the oxygen concentration in the tank 2 and to prevent the waste solvent from volatilizing and to take an explosion-proof measure for the tank 2.

  In addition, when the concentration value of the oxygen concentration meter 8 becomes a predetermined value (5%) or more while receiving the waste solvent, an alarm is issued to alert the facility manager and the like. At this time, in order to further improve safety, not only the generation of an alarm, but also the operation of the receiving pump 12 may be stopped and the acceptance of the waste solvent into the tank 2 may be interrupted.

  On the other hand, when the waste solvent stored in the tank 2 is supplied to the cement kiln burner 25, first, the valve 14 is opened to open the fuel supply line 4, and the blow pump 15 is driven to The waste solvent is extracted from the lower part and the supply to the cement kiln burner 25 is started.

  After that, when the storage amount of the waste solvent in the tank 2 decreases, the internal pressure of the tank 2 decreases, and when it becomes equal to or lower than the second set value TP2 (13 kPa), the supply control valve 33 is opened to supply nitrogen. The pipe 5 is opened, and nitrogen gas is supplied to the tank 2 to pressurize the tank 2. Thereafter, the supply of nitrogen gas is continued until the internal pressure of the tank 2 becomes equal to or higher than the first set value TP1 (18 kPa), thereby maintaining the internal pressure of the tank 2 at the set value TP2 (13 kPa) or higher. Prevents inflow of water and volatilization of waste solvent.

  Even when the waste solvent is supplied, if the concentration value of the oxygen concentration meter 8 becomes a predetermined value (5%) or more, an alarm is issued to alert the facility manager and the like. Also at this time, in order to further improve safety, not only the issuing of an alarm, but also the operation of the blowing pump 15 may be stopped and the extraction of the waste solvent from the tank 2 may be interrupted.

  As described above, according to the present embodiment, instead of adjusting the supply amount of nitrogen gas according to the oxygen concentration in the tank 2, the internal pressure of the tank 2 is maintained at a certain value or more using nitrogen gas. It becomes possible to reduce the consumption of nitrogen gas.

  In addition, when the internal pressure in the tank 2 is equal to or higher than the first set value TP1 (18 kPa), the nitrogen supply line 5 is closed, and a second value that is smaller than the first set value TP1 (18 kPa) and larger than the atmospheric pressure. Therefore, after the nitrogen supply line 5 is closed, the internal pressure of the tank 2 is increased to the second value. The state is maintained until the set value TP2 (13 kPa) or less, and conversely, even when the nitrogen supply line 5 is opened, the internal pressure of the tank 2 becomes the first set value TP1 (18 kPa) or more. The state is maintained. As a result, even when the internal pressure of the tank 2 is likely to fluctuate, such as when the waste solvent is received or supplied, it is possible to prevent the nitrogen supply conduit 5 from being frequently opened and closed, and nitrogen gas is wasted. The internal pressure of the tank 2 can be kept at a predetermined pressure value or higher while suppressing consumption. Therefore, it is possible to reduce the consumption of nitrogen gas while reliably avoiding the danger of explosion.

  In addition, since the breathing valve 35 that opens the atmosphere opening pipe 6 is provided when the internal pressure of the tank 2 becomes equal to or higher than the third setting value TP3 (18 kPa) that is equal to or higher than the first setting value TP1 (18 kPa), The open pipe 6 is opened only when the internal pressure of the tank 2 is likely to rise significantly, such as when a waste solvent is received. Normally, the deodorizer 34 has a lower deodorizing function as the frequency of use increases. However, according to the present embodiment, the frequency of opening the atmosphere opening pipe line 6 decreases, and therefore the frequency of use of the deodorizer 34 is decreased. be able to. Thereby, the lifetime of the deodorizing machine 34 can be prolonged, and it becomes possible to aim at reduction of the effort and maintenance cost of replacement work.

  In the above embodiment, the case where the fuel supply line 4 is connected to the cement kiln burner 25 and the waste solvent is used as the cement firing fuel is exemplified. However, the present invention uses the waste solvent as the cement firing fuel. The system is not limited to use, and can be widely applied to any system that temporarily stores waste solvent in a tank and then supplies it as a part of fuel.

  In the above embodiment, the pressure resistance of the tank 2 is described as 20 kPa. However, the pressure resistance of the tank 2 is not limited to 20 kPa, and can take various values depending on the pressure resistance of the tank 2. The values of the first to third setting values TP1 to TP3 can be changed as appropriate. Further, the oxygen concentration that is a reference for issuing an alarm is not limited to 5%, and can be changed as appropriate according to the installation location of the storage system 1, the properties of the low flash point fuel, and the risk level. .

It is a flowchart which shows one Embodiment of the storage system of the low flash point fuel concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Low flash point fuel storage system 2 Tank 3 Acceptance line 4 Fuel supply line 5 Nitrogen supply line 6 Atmospheric open line 7 Gas return line 8 Oxygen meter 9 Circulation line 10 Stirring pump 11 Roller vehicle 12 Acceptance Pump 13 Strainer 14 Valve 15 Blow pump 16 Flow meter 17 Speed controller 18 Flow path 19 Valve 20 Pressure gauge 25 Cement kiln burner 26 Fuel return line 27 Steam supply line 28 Nitrogen generator 29 Nitrogen tank 30 Pressure gauge 31 Valve 32 Pressure gauge 33 Supply control valve 34 Deodorizer 35 Breathing valve 36 Pressure gauge 37 Valve

Claims (5)

A tank for storing low flash point fuel;
A receiving conduit for accepting low flash point fuel and charging it into the tank;
An extraction line for extracting the low flash point fuel stored in the tank;
An inert gas supply line for supplying an inert gas to the tank;
The inert gas supply line is disposed on the inert gas supply line, and when the internal pressure of the tank exceeds a first set value, the inert gas supply line is closed, and the internal pressure of the tank is set to the first set value. when it is less smaller atmospheric pressure greater than the second set value, the supply control valve to open the inert gas supply line,
An oxygen concentration measuring means for measuring the oxygen concentration in the tank ,
When the concentration value measured by the oxygen concentration measuring means exceeds a predetermined value, an alarm is issued, the acceptance of the low flash point fuel into the tank is stopped, and the low flash point fuel is extracted from the tank. A low flash point fuel storage system, wherein one or more selected from the stop are performed . An open air conduit for releasing the gas in the tank to the atmosphere;
Deodorizing means for deodorizing the gas flowing in the atmosphere open pipe;
It is arranged on the atmosphere open conduit, and the internal pressure of the tank is smaller than the pressure resistance of the tank and the first
2. The low flash point fuel storage system according to claim 1, further comprising: an air release valve that opens the air release pipe when a value equal to or greater than a third set value that is greater than the set value of 1 is set. . Wherein when receiving a low flash point fuels, wherein a portion of the gas in the tank, to claim 1 or 2, characterized in that it comprises a feedback line for feeding back to the carrying means for carrying the low flash point fuel Low flash point fuel storage system. The low flash point fuel storage system according to claim 3 , wherein the carrying-in means is a tank truck. The extraction pipe is connected to a cement burning facility, low flash according to any one of claims 1 to 4 low flash point fuel stored in the tank, characterized in that it is supplied as a cement burning fuel Spot fuel storage system.

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