JP2000146088A - Supply method of high pressure hazardous gas and feeder device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of spontaneous combustion, explosion, etc., by filling a feeder pipe of hazardous gas with high pressure inactive gas, thereafter supplying high pressure hazardous gas at a pressure a little larger than a pressure of the inactive gas to the feeder pipe of hazardous gas. SOLUTION: In the case of processing organic waste water by using high pressure oxygen as an oxidizer, after pressure reducing nitrogen in a nitrogen supply source 2, a part from a pipe 9a to an inflow side of a control valve 4 of a pipe 10 is filled with nitrogen after pressure reduction by opening each valve 3 of the pipes 9a, 10 and closing the control valve 4. Next liquid oxygen in an oxygen supply source 1 is pressure boosted, and evaporated gasified high pressure oxygen is supplied in a pipe 9b by opening the valve 3. A flow amount discharged from the control valve 4 is set to a prescribed value by a flow indicating adjusting meter 7, high pressure nitrogen is released to the outside from the pipe 10 via a reactor 8, on the other hand, the organic waste water is supplied in the reactor 8 from the pipe 11. Then the organic waste water is instantaneously changed in carbon dioxide and water, simultaneously with obtaining a small amount of ash.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for supplying a high-pressure dangerous gas.

[0002]

2. Description of the Related Art A method for oxidizing various substances using high-pressure oxygen, which is a kind of high-pressure dangerous gas, as an oxidizing agent is widely known. For example, the oxidation of organic materials to carbon dioxide and water is a known process and is often used to dispose of waste and / or for heating and power generation. When energy is recovered in the form of steam, the temperature of the steam produced is usually below 300 ° C., typically below 250 ° C. Thus, the recovered heat is of low value and much lower than the temperature required to generate power in modern steam generating plants.

Therefore, it has been proposed to recover thermal energy from a supercritical water fluid in order to obtain high-temperature steam. For example, under the supercritical condition of water, the organic chain bond is broken and the toxic organic material is reformed to make it a harmless low-molecular material.
In order to dispose of the resulting non-toxic materials by ordinary means and obtain useful energy, Japanese Patent Publication No.
No. 32 discloses that "a reaction mixture of an organic substance, water and oxygen is formed, and the mixture is formed at a temperature of 377 ° C. or higher and 220 ° C.
Obtaining useful energy in an oxidation reactor characterized in that the organic substance is oxidized by reacting in a single homogeneous fluid phase at a pressure equal to or higher than atmospheric pressure, thereby raising the temperature of the water and oxidation products; Method for oxidizing organic substances ". The method of oxidizing an organic substance described in this publication will be specifically described. As shown in FIG. 2, a feed of an organic material is passed through a line 12 through a feed slurry tank 1.
3 and the conditioned water also passes through line 14 to tank 13
Supplied to Water and organic material from tank 13 are in line 1
5. Feed pump 16, extractor 18 via line 17
And through line 19, heated to a temperature of 377 ° C. or higher and immediately before oxidation reactor 20. On the other hand, air or oxygen from the source 21 passes through the line 22 and is pressurized to 220 atm or more by the oxidizing agent compressor 23, passes through the line 24, and is mixed with the organic substance and the conditioning water passing through the line 19 to form an oxidation reactor. Form a reaction mixture that goes into 20. After oxidizing the organic material in a supercritical state in the oxidation reactor 20, the effluent from the oxidation reactor 20 reaches the ash separator 26 via the line 25, where ash and inorganic salts are discharged from the bottom, and the effluent is The gas passes through a line 27 to an expansion turbine 28, and is extracted as useful energy in the form of high-pressure steam at an outlet 29.

In oxidizing an organic substance in a supercritical state as described above, air or oxygen is pressurized to a high pressure of 220 atm or more. In this case, when the low-pressure oxygen is rapidly increased to a high pressure of 220 atm or more by the compressor 23,
Since the change is almost irreversible and adiabatic, the temperature of oxygen abnormally increases due to adiabatic compression. If the temperature and pressure of oxygen before pressure increase are T ₁ and P ₁ , respectively, and the temperature and pressure of oxygen after pressure increase are T ₂ and P ₂ , respectively, T ₂ / T ₁ = (P ₂ / P ₁ ) ^{(k-1) / k} . In the above equation, T ₁ = 20 ° C., P ₂ = 220 atm, P ₁ =
By substituting 1 atm and k (specific heat ratio) = 1.4, T ₂ =
1084 ° C. At such an extremely high temperature, not only a sealing material such as a gasket in the oxygen supply pipe may ignite and melt, but also the oxygen supply pipe itself may ignite and melt. Further, rust and foreign matter in the oxygen supply pipe easily ignite spontaneously.

As a means for avoiding such an inconvenience, if the pressure of oxygen is increased very slowly, an abnormal increase in temperature can be prevented, but the working efficiency is greatly reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a high pressure hazard piping system for supplying hazardous gas or a device using hazardous gas. An object of the present invention is to provide a method and a device for supplying a high-pressure dangerous gas which does not cause an inconvenience such as spontaneous ignition when supplying the gas.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for supplying a high-pressure hazardous gas to a hazardous gas supply pipe or an apparatus that causes an oxidation reaction under high temperature and high pressure. A gas supply pipe or a device that causes an oxidation reaction under high temperature and high pressure is filled with a high-pressure inert gas to increase the pressure of the pipe or the device. Since inert gas is present in the piping or the apparatus, even if the temperature rises due to adiabatic compression, it does not ignite. Next, a high-pressure dangerous gas having a pressure slightly higher than the pressure of the inert gas (a pressure of 1.1 times or more, preferably twice or more of the pressure of the inert gas) is supplied to a dangerous gas supply pipe or a high-temperature high-pressure pipe. If it is supplied to a device that causes an oxidation reaction under a low pressure, almost no adiabatic heat of compression is generated, and the gas inside the dangerous gas supply pipe or the device that causes the oxidation reaction under high temperature and high pressure is changed from an inert gas to a high pressure dangerous gas. Can be replaced by

In particular, flammable gases such as hydrogen and acetylene, which are a kind of dangerous gas, when heated from a low pressure to a high pressure sharply, exceed the ignition temperature (for example, the ignition temperature of hydrogen is 585 ° C.) due to adiabatic compression. To rise. In this case, if oxygen is present, an explosion may occur.
Therefore, according to the present invention, if a method of supplying a high-pressure inert gas in advance into a dangerous gas supply pipe or a device that causes an oxidation reaction under high temperature and high pressure is adopted, the high-pressure inert gas is replaced with a high-pressure flammable gas. At this time, the temperature rise hardly occurs, and since the oxygen in the piping or the apparatus is removed by the inert gas supplied in advance, the high-pressure flammable gas does not explode.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a method for supplying a high-pressure hazardous gas to a hazardous gas supply pipe, wherein a high-pressure inert gas is supplied to the pipe before the high-pressure hazardous gas is supplied to the pipe. Supplying a high-pressure dangerous gas having a pressure slightly higher than the pressure of the inert gas to the piping to replace the inert gas with the high-pressure dangerous gas; A first invention is a method of supplying a high-pressure dangerous gas to a supply pipe, and a method of supplying a high-pressure dangerous gas to a device that causes an oxidation reaction under high temperature and high pressure, and supplying the high-pressure dangerous gas to the device. Supplying a high-pressure inert gas to the device before, and then supplying a high-pressure dangerous gas having a pressure slightly higher than the pressure of the inert gas to the device to replace the inert gas with the high-pressure dangerous gas. Oxidation reaction under high temperature and high pressure characterized by A method for supplying a high-pressure hazardous gas to an initiating device is defined as a second invention. In the second invention, the device for initiating an oxidation reaction under high temperature and high pressure in which the oxidation reaction is a supercritical or subcritical hydroxylation reaction The method for supplying the high-pressure dangerous gas to the third invention is the third invention, and in the first, second, or third invention, the supply pressure of the high-pressure dangerous gas is 2 to 4 times the pressure of the inert gas. The method for supplying a dangerous gas is a fourth invention, and in the first, second, third or fourth invention, the high-pressure dangerous gas is high-pressure oxygen, a high-pressure gas containing oxygen, or a high-pressure flammable gas. The fifth invention is a method for supplying a high-pressure hazardous gas, and a pressure gauge and a control valve equipped with a flow rate indicating controller are arranged in this order in the hazardous gas supply pipe. High-pressure hazardous gas through the A high pressure hazardous gas supply apparatus, wherein a pipeline for supplying high pressure inert gas from a high pressure inert gas supply source via a pressure gauge and a valve is connected to the dangerous gas supply pipe. Is the sixth invention.

As the gas containing oxygen, for example, air can be used.

The flammable gas is defined as air in normal temperature and normal pressure air.
A gas having a property of sustaining combustion when ignited, and examples thereof include hydrogen, acetylene, methane, benzene, ethylene oxide, pyridine, and vinyl chloride.

As used herein, the term "supercritical" refers to a region in which water exceeds a critical temperature of 374 ° C. and a critical pressure of 218 atm. In addition, “subcritical” is a state immediately before reaching supercritical, and the temperature is 150 to 374 ° C.
The pressure means a range of 50 to 218 atm. The subcritical water oxidation treatment is less efficient than the supercritical water oxidation treatment, but is used when complete decomposition is not required.

The pressurization of the inert gas is performed in an adiabatic compression manner,
Even if the temperature of the inert gas rises, it does not spontaneously ignite, but instead of increasing rapidly (adiabatically), if the pressure is increased slowly (or to allow heat exchange with the outside), This is more preferable because the temperature rise of the inert gas is reduced. As the inert gas, He, Ne, Ar, Kr,
Although a rare gas such as Xe or nitrogen can be used, it is preferable to use nitrogen from the viewpoint of economy.

The reason why the supply pressure of the high-pressure oxygen is preferably set to 2 to 4 times the pressure of the inert gas is as follows. (1) When the supply pressure of the high-pressure oxygen exceeds four times the pressure of the inert gas (for example, when the pressure of the high-pressure oxygen is 300 kg / c
m ² , when the pressure of nitrogen is less than 75 kg / cm ² ) When supplying high-pressure oxygen, the oxygen pressure in the pipe rapidly rises, the heat generated by the adiabatic compression is large, and there is a possibility of spontaneous ignition. If the pressure of the inert gas is further reduced, the change in oxygen pressure is further increased, so that the heat generation is large and the possibility of spontaneous ignition increases.

(2) When the supply pressure of the high-pressure oxygen is less than twice the pressure of the inert gas (for example, when the pressure of the high-pressure oxygen is 30
0 kg / cm ² and the nitrogen pressure exceeds 150 kg / cm ² ) When high-pressure oxygen is supplied, the change in the oxygen pressure in the pipe is small, so that there is no heat generation due to adiabatic compression that ignites spontaneously. Therefore, even if the nitrogen pressure is further increased, only a large amount of nitrogen gas is consumed, which is not economical.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the present invention will be specifically described below with reference to FIG. 1 which shows a schematic configuration of an apparatus suitable for carrying out the method of the present invention. In FIG. 1, 1 is an oxygen supply source, and 2 is a nitrogen supply source. Reference numeral 3 denotes a valve, 4 denotes a control valve, 5 denotes a trap, 6 denotes a pressure gauge, 7 denotes a flow rate indicating controller, and 8 denotes a reactor. As an example, a case where organic wastewater discharged from a factory is treated using the apparatus configured as described above will be described.

A pressure of 400 kg / cm ² as a nitrogen supply source
The nitrogen in the cylinder is supplied to a predetermined pressure (75 to 150 kg / c) by a pressure reducing valve (not shown).
m ² ), the valve 3 of the pipe 9 a (a pipe for supplying a high-pressure inert gas) and the pipe 3 of the pipe 10 (hazardous gas supply pipe) are opened, the control valve 4 is closed, and the pipe 10 a Up to the inflow side of the control valve 4 is filled with nitrogen after the above pressure reduction. Next, the pressure of liquid oxygen as the oxygen supply source 1 was increased to about 300 kg / cm ² ,
The gasified high-pressure oxygen is supplied into the pipe 9b by opening the valve 3 of the pipe 9b (a pipe for supplying a high-pressure dangerous gas). Then, the flow rate discharged from the control valve 4 is set to a predetermined value by the flow rate controller 7, and high-pressure nitrogen is supplied from the pipe 10 to the reactor 8 by pressing with high-pressure oxygen.
And organic wastewater at a temperature of 370 to 400 ° C. is supplied from the pipe 11 into the reactor 8. This organic wastewater is instantaneously changed into carbon dioxide and water, and at the same time, a small amount of ash (inorganic substance) is obtained. The amount of heat stored in the supercritical water, which has been heated to a high temperature by the heat of the oxidation reaction, can be used for generating power, generating steam, or raising the temperature of organic wastewater supplied to the reactor 8.

In the above embodiment, the organic wastewater discharged from the factory is treated. In addition, wastewater containing a hardly decomposable organic chlorine compound such as PCB and dioxin, chlorofluorocarbon, sewage sludge and the like are treated. You can also.

Although nitrogen is used as the inert gas because it is easily available and inexpensive, the present invention is not limited to this, and a rare gas can be used if necessary.

Further, the method of the present invention is not limited to the case of treating organic substances in a supercritical state or a subcritical state, but also as a fire prevention safety measure for general pressure vessels filled with high-pressure oxygen or high-pressure flammable gas. It can also be used. Others
The method of the present invention can be applied to a wet oxidation method and the like.

[0021]

Since the present invention is constructed as described above, when supplying a high-pressure hazardous gas to a hazardous gas supply pipe or a device that causes an oxidation reaction under high temperature and high pressure, there are disadvantages such as spontaneous ignition and explosion. It is possible to provide a method for supplying a high-pressure hazardous gas and a device for supplying the same without causing any trouble.

[Brief description of the drawings]

FIG. 1 is a schematic structural diagram of an apparatus suitable for applying the method of the present invention.

FIG. 2 is a system diagram showing an example of an apparatus for burning an organic substance using high-pressure oxygen.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Oxygen supply source 2 ... Nitrogen supply source 3 ... Valve 4 ... Control valve 5 ... Trap 6 ... Pressure gauge 7 ... Flow rate controller 8 ... Reactor 9a, 9b, 10, 11 ... Piping

Claims (6)

[Claims] 1. A method for supplying a high-pressure dangerous gas to a dangerous gas supply pipe, comprising supplying a high-pressure inert gas to the pipe before supplying the high-pressure dangerous gas to the pipe, Supplying a high-pressure dangerous gas having a pressure slightly higher than the pressure of the inert gas to the piping to replace the inert gas with the high-pressure dangerous gas; Supply method. 2. A method for supplying a high-pressure hazardous gas to an apparatus that causes an oxidation reaction under high temperature and high pressure, comprising supplying a high-pressure inert gas to the apparatus before supplying the high-pressure hazardous gas to the apparatus. Then, an apparatus for initiating an oxidation reaction under high temperature and high pressure, characterized in that a high-pressure dangerous gas having a pressure slightly higher than the pressure of the inert gas is supplied to the above-mentioned apparatus to replace the inert gas with the high-pressure dangerous gas. To supply high pressure hazardous gas to the 3. The method according to claim 2, wherein the oxidation reaction is a supercritical water oxidation reaction or a subcritical water oxidation reaction. 4. The method for supplying a high-pressure dangerous gas according to claim 1, wherein the supply pressure of the high-pressure dangerous gas is 2 to 4 times the pressure of the inert gas. 5. The high-pressure hazardous gas is high-pressure oxygen, high-pressure gas containing oxygen, or high-pressure flammable gas.
5. The method for supplying a high-pressure dangerous gas according to 3 or 4. 6. A danger gas supply pipe is provided with a pressure gauge and a control valve provided with a flow rate indicating controller in this order,
A line for supplying a high-pressure hazardous gas from a high-pressure hazardous gas supply source via a pressure gauge and a valve and a line for supplying a high-pressure inert gas from a high-pressure inert gas supply source via a pressure gauge and a valve are defined as the above hazards. A high-pressure dangerous gas supply device connected to a gas supply pipe.