JP5204530B2 - Gas hydrate manufacturing equipment - Google Patents

Description

  The present invention relates to a gas hydrate comprising a reaction generation unit that reacts a raw material gas and water under low temperature and high pressure to generate a primary gas hydrate, and a liquid cooling unit that cools a liquid in the reaction generation unit. It relates to a manufacturing apparatus.

  In gas hydrate, gas molecules such as hydrocarbons such as methane, ethane, propane, and butane, which are natural gas components, and carbon dioxide are taken into the interior of the three-dimensional structure formed by combining water molecules. It is a general term for clathrate hydrates (hydrates) formed in this way. That is, the gas hydrate is an ice-like solid substance composed of source gas molecules and water molecules, and is a stable clathrate compound in which source gas molecules are included inside a three-dimensional cage structure formed by water molecules. It is a kind. This gas hydrate has a relatively large gas storage capacity, and has characteristic properties such as large generation / decomposition energy and selectivity of hydrated gas. For example, transportation and storage of natural gas, etc. Various applications such as means, heat storage systems, actuators, and separation and recovery of specific component gases are possible, and research is actively conducted.

  Gas hydrate is usually generated under high pressure and low temperature conditions. The following methods are well known as generation methods. By spraying cooled water from the top of the reaction vessel filled with raw material gas at high pressure, so-called "water spray method", in which gas hydrate is generated on the surface of the water droplet when the water droplet falls in the raw material gas, reaction A so-called “bubbling method” or the like is performed such that gas hydrate is generated on the surface of the bubbles when the bubbles of the source gas rise in the water by introducing the source gas into the water in the container as bubbles.

  In the bubbling method, the gas hydrate generated in the water in the reaction vessel floats in the water because the specific gravity is smaller than that of water. Then, the amount of gas hydrate increases with the progress of the production reaction and is slurried by stirring. Usually, when the content of gas hydrate in the slurry becomes about 10 wt% to 20 wt%, the generated gas hydrate is extracted out of the reaction vessel in a slurry state.

  The extracted gas hydrate in the slurry state is passed through a dehydrator to be dehydrated and the gas hydrate content is increased to about 40 wt% to 50 wt%. In this state, it is sent to the next generation step for further increasing the gas hydrate content to about 90 wt%.

  FIG. 5 shows a schematic configuration diagram of a conventional gas hydrate manufacturing apparatus (for example, Patent Document 1). A reaction generator 1 that generates a primary gas hydrate 6 by reacting a raw material gas and water under low temperature and high pressure, a liquid cooling unit 2 that cools the liquid in the reaction generator 1, and the reaction generator The slurry of the primary gas hydrate 6 generated in 1 is sent through the slurry pump 10, and the dehydrating device 3 for concentrating the slurry, the concentrated slurry dehydrated by the dehydrating device 3 and the raw material gas are reacted again. And a second reaction generation unit 5 that generates a high concentration secondary gas hydrate 4.

The liquid cooling unit 2 is provided to suppress an increase in the liquid temperature in the reaction generation unit 1 because the gas hydrate generation reaction is an exothermic reaction. As shown in FIG. 5, the liquid cooling unit 2 includes a circulation line 7 that extracts liquid from the first reaction generation unit 1 and returns the liquid, a circulation pump 8 provided in the circulation line 7, The heat exchanger 9 is provided downstream from the circulation pump 8 in the circulation direction.
JP 2006-111746 A

  However, when the slurry of the primary gas hydrate 6 generated in the reaction generation unit 1 is extracted and cooled in the heat exchanger 9, the liquid temperature of the slurry can be lowered, but the liquid temperature decrease is caused by the gas hydrate generation reaction. Acts in the forward direction. As a result, there is a problem that gas hydrate is generated and adhered in the heat exchanger 9 and the flow path is blocked.

  In the conventional structure, since the heat exchanger 9 is arranged on the downstream side of the circulation pump 8, once the heat exchanger 9 is blocked due to the generation and adhesion of gas hydrate, the pump of the circulation pump 8 is used. Pressure is applied to the occluded portion to further increase the pressure in the occluded portion. That is, there is a problem in that the gas hydrate production reaction is further advanced, and the production and adhesion of gas hydrate in the blocked portion is further increased.

  The object of the present invention is to automatically change the direction in which the decomposition reaction of gas hydrate proceeds when the blockage based on the gas hydrate occurs in the flow passage of the portion cooled by the cooling unit of the liquid cooling unit. An object of the present invention is to provide a gas hydrate manufacturing apparatus that can reduce the above problem.

  In order to achieve the above object, a gas hydrate production apparatus according to the first aspect of the present invention includes a reaction generator that reacts a raw material gas and water under low temperature and high pressure to generate gas hydrate. A liquid cooling unit that cools the liquid in the reaction generation unit, the liquid cooling unit extracting and returning the liquid from the reaction generation unit, and a circulation pump provided in the circulation line; A cooling unit provided in the circulation line and positioned on the upstream side in the circulation direction from the circulation pump.

  According to this aspect, in the circulation line, the cooling unit is provided on the upstream side in the circulation direction with respect to the circulation pump. Therefore, when a blockage based on gas hydrate occurs in the flow path of the portion cooled by the cooling unit, the pump pressure of the circulation pump acts as a suction force on the closed portion, and the pressure of the blocked portion Is automatically lowered by the pump pressure (suction force). When the pressure falls below the equilibrium pressure for gas hydrate decomposition, the gas hydrate decomposition reaction that caused the blockage begins, proceeds, and the blockage is eliminated.

  According to a second aspect of the present invention, in the gas hydrate manufacturing apparatus according to the first aspect, the upstream side of the circulation pump of the circulation line includes a plurality of switchable flow paths, A cooling section provided in each flow path, a pressure sensor that is provided between each cooling section and the circulation pump, and detects a pressure in each flow path; and a detection signal of the pressure sensor; And a control unit that outputs a control signal for switching a plurality of flow paths.

  For example, when one block is used and a circulation line is configured, and the liquid in the reaction generation unit is cooled by circulating the circulation line and the blockage occurs, the suction of the pump pressure is performed. The pressure at the closed portion is lowered by the force and the gas hydrate decomposition reaction starts, but the decomposition reaction proceeds slowly and may take a long time. This embodiment is effective in such a case.

  That is, according to this aspect, when the blockage occurs in “one channel”, the control unit can switch to “other channels”, so the blockage in “one channel” is eliminated. The normal operation state can be ensured without waiting for the operation. At that time, the gas hydrate is decomposed as described above by changing the suction force of the circulation pump to the closed portion of the “one channel” while switching to the “other channel”. Even when the progress of the reaction is slow and takes a long time, the normal operation for cooling the liquid using the “other flow path” is performed, and the decomposition reaction is surely terminated to eliminate the blockage. It can be returned to the state.

  According to a third aspect of the present invention, in the gas hydrate manufacturing apparatus according to the first aspect, the first on-off valve provided on the upstream side in the circulation direction of the cooling unit, the circulation pump, and the cooling unit And a control unit that performs control to close the first on-off valve when a pressure equal to or lower than the decomposition equilibrium pressure of the gas hydrate is detected by the pressure sensor. Is.

  When the blockage of the flow path due to gas hydrate generation or adhesion occurs, the pressure of the blockage part is automatically lowered by the pump pressure of the circulation pump, but it is below the equilibrium pressure of gas hydrate decomposition. If not lowered, sufficient decomposition will not occur.

  According to this aspect, since the control of closing the first on-off valve provided on the upstream side of the cooling unit when the pressure sensor detects a gas hydrate decomposition equilibrium pressure or lower is performed, In a state where they are isolated from each other, a pressure equal to or lower than the decomposition equilibrium pressure can be applied. Thereby, the decomposition reaction of the gas hydrate proceeds at a stretch, and the decomposition reaction can be completed in a short time. Therefore, after that, by returning the first on-off valve to the open state, it is possible to return from the closed state to the normal state in a short time.

  According to a fourth aspect of the present invention, there is provided the gas hydrate manufacturing apparatus according to the third aspect, wherein the liquid flow path in the cooling unit is branched and connected to the upstream of the circulation pump; A second on-off valve provided in the branch flow path, wherein the control unit closes the first on-off valve when the pressure sensor detects a gas hydrate decomposition equilibrium pressure or lower, and the second on-off valve It is comprised so that control which opens may be performed.

  According to this aspect, the liquid flow channel in the cooling unit is branched and connected to the upstream of the circulation pump, and the second open / close valve provided in the branch flow channel is provided. In addition to closing the first on-off valve when the pressure sensor detects a gas hydrate decomposition equilibrium pressure or lower, control is performed to open the second on-off valve. Since the decomposition pressure can be applied also from the passage, the decomposition reaction of the gas hydrate can be advanced more rapidly, and the decomposition reaction can be completed in a shorter time.

  According to a fifth aspect of the present invention, in the gas hydrate manufacturing apparatus according to the first aspect, an upstream on-off valve and a downstream on-off valve respectively provided on the upstream side and the downstream side of the cooling unit, and the circulation A pressure sensor provided between the pump for cooling and the cooling part, a suction part provided between the upstream on-off valve and the downstream on-off valve, and a pressure drop of a magnitude set by the pressure sensor And a control unit that performs control to close the upstream side opening / closing valve and the downstream side opening / closing valve and operate the suction unit.

  According to this aspect, when the pressure sensor detects that the pressure has decreased to some extent after the blockage starts, the upstream side open / close valve and the downstream side open / close valve respectively provided on the upstream side and the downstream side of the cooling unit are closed to close the closed part. Can be isolated in pressure, and the suction part can be operated to apply a large suction force to the closed part, so that the decomposition reaction of gas hydrate proceeds at once and the decomposition reaction is completed in a short time. Is possible. Therefore, after that, by returning the upstream side opening / closing valve and the downstream side opening / closing valve to the open state and stopping the suction part, the closed state can be restored to the normal state in a short time.

  According to the present invention, in the circulation line, the cooling unit is provided upstream of the circulation pump in the circulation direction. Therefore, when a blockage based on gas hydrate occurs in the flow path of the portion cooled by the cooling unit, the pump pressure of the circulation pump acts as a suction force on the closed portion, and the pressure of the blocked portion Is automatically lowered by the pump pressure (suction force). When the pressure falls below the equilibrium pressure for gas hydrate decomposition, the gas hydrate decomposition reaction that caused the blockage begins, proceeds, and the blockage is eliminated.

[Embodiment 1]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing a gas hydrate manufacturing apparatus according to Embodiment 1 of the present invention. The apparatus for producing a gas hydrate according to the present embodiment generates a primary gas hydrate 6 by reacting a raw material gas and water under a low temperature (about 3 ° C.) and a high pressure (about 5.5 MPa). Unit 1, a liquid cooling unit 2 that cools the liquid in the reaction generation unit 1, and a slurry of the primary gas hydrate 6 generated in the reaction generation unit 1 is sent via a slurry pump 10, and the slurry is concentrated And a second reaction generation unit 5 that generates a high-concentration secondary gas hydrate 4 by reacting the concentrated slurry dehydrated by the dehydration device 3 with the raw material gas again. Yes.

  In addition, it is also possible to comprise as follows, without providing the 2nd reaction production | generation part 5. FIG. That is, the concentrated slurry dehydrated by the dehydrating device 3 can be sent to a molding process to be pelletized.

  Although the liquid cooling unit 2 will be described repeatedly, since the gas hydrate production reaction is an exothermic reaction, the liquid cooling unit 2 is provided to suppress an increase in the liquid temperature in the reaction production unit 1. As shown in FIG. 1, the liquid cooling unit 5 includes a circulation line 7 that draws liquid from the first reaction generation unit 1 and returns the liquid, a circulation pump 8 provided in the circulation line 7, The heat exchanger 9 is provided upstream of the circulation pump 8 in the circulation direction.

  The operational effects of the second embodiment will be described. In the circulation line 7, the heat exchanger 9 is provided upstream of the circulation pump 8 in the circulation direction. Therefore, when the blockage based on the gas hydrate occurs in the flow path of the portion cooled by the heat exchanger 9, the pump pressure of the circulation pump 8 acts as a suction force on the blocked portion. The pressure in the closed portion is automatically reduced by the pump pressure (suction force). When the pressure falls below the equilibrium pressure for gas hydrate decomposition, the gas hydrate decomposition reaction that caused the blockage begins, proceeds, and the blockage is eliminated.

[Embodiment 2]
FIG. 2 is a schematic configuration diagram showing a gas hydrate manufacturing apparatus according to Embodiment 2 of the present invention. The gas hydrate manufacturing apparatus according to the present embodiment includes two switchable flow paths 7a and 7b on the upstream side of the circulation pump 8 in the circulation line 7, and each flow path 7a, Heat exchangers 9a and 9b respectively provided in 7b, and pressure sensors 11a provided between the heat exchangers 9a and 9b and the circulation pump 8 to detect the pressure in the flow paths 7a and 7b. 11b, and a control unit 20 that receives detection signals of the pressure sensors 11a and 11b and outputs a control signal for switching the two flow paths 7a and 7b. In FIG. 2, reference numerals 13a and 13b denote on-off valves.

  The on-off valve 13a is opened, the on-off valve 13b is closed, the one flow path 7a is used, the circulation line 7 is configured, and the liquid in the reaction generation unit 1 is cooled by circulating the circulation line 7. When the blockage occurs, the pressure of the blockage portion is lowered by the suction force of the pump pressure of the circulation pump 8, and the gas hydrate decomposition reaction starts.

  That is, according to the second embodiment, when the blockage occurs in one flow path 7a, the control unit 20 can switch to another flow path 7b with the on-off valve 13a closed and the on-off valve 13b opened. Therefore, the normal operation state can be ensured without waiting until the blockage of the one flow path 7a is resolved. At that time, since the suction force of the circulation pump 10 is also applied to the closed portion of the one flow path 7a in the state switched to the other flow path 7b, the decomposition reaction of the gas hydrate as described above. Even if the progress of the gas is slow and takes a long time, the gas hydrate decomposition reaction is surely terminated while the normal operation for cooling the liquid using the other flow path 7b is performed, and the blockage is eliminated. The initial state can be restored.

[Embodiment 3]
FIG. 3 is a schematic configuration diagram showing a gas hydrate manufacturing apparatus according to Embodiment 3 of the present invention. The gas hydrate manufacturing apparatus according to the present embodiment includes a first on-off valve 15 provided on the upstream side in the circulation direction of the heat exchanger 9, a circulation pump 8, and the heat exchanger 9. The pressure sensor 11 is provided, and a control unit 20 that performs control for closing the first open / close 15 valve when the pressure sensor 11 detects a gas hydrate decomposition pressure equal to or lower than the decomposition equilibrium pressure. .

  In addition, the liquid flow path in the heat exchanger 9 is branched and connected to the upstream of the circulation pump 8, and the second open / close valve 18 provided in the branch flow path 17 is provided. The control unit 20 is configured to perform control to close the first on-off valve 15 and further open the second on-off valve 18 when the pressure sensor 11 detects a gas hydrate decomposition equilibrium pressure or lower. Has been.

  When the clogging of the flow path due to the generation and adhesion of gas hydrate occurs, the pressure of the clogging portion is automatically reduced by the pump pressure of the circulation pump 8, but below the equilibrium pressure of gas hydrate decomposition. If it does not go down, sufficient decomposition will not occur.

  According to the third embodiment, since the first on-off valve 15 provided on the upstream side of the heat exchanger 9 is closed when the pressure sensor 11 detects a gas hydrate decomposition equilibrium pressure or lower, the closed portion Can be made to be in a pressure-isolated state, and a pressure equal to or lower than the decomposition equilibrium pressure can be applied. Thereby, the decomposition reaction of the gas hydrate proceeds at a stretch, and the decomposition reaction can be completed in a short time. Thereafter, by returning the first on-off valve 15 to the open state, it is possible to return from the closed state to the normal state in a short time.

  Further, the control unit 20 opens the second on-off valve 18 in addition to closing the first on-off valve 15 when the pressure sensor 11 detects a gas hydrate decomposition equilibrium pressure or lower, so that Decomposition pressure can also be applied to the closed portion from the branch channel 17. Therefore, the decomposition reaction of the gas hydrate can be advanced more rapidly, and the decomposition reaction can be completed in a shorter time.

[Embodiment 4]
FIG. 4 is a schematic configuration diagram showing a gas hydrate manufacturing apparatus according to Embodiment 4 of the present invention. The gas hydrate manufacturing apparatus according to the present embodiment includes an upstream on-off valve 21 and a downstream on-off valve 22 provided on the upstream side and the downstream side of the heat exchanger 9, the circulation pump 8, and the heat. The pressure sensor 11 provided between the exchanger 9, the suction part 23 provided between the upstream side open / close valve 21 and the downstream side open / close valve 22, and the pressure sensor 11 having a set size. When a pressure drop is detected, the control unit 20 includes a control unit 20 that performs control for closing the upstream side open / close valve 21 and the downstream side open / close valve 22 and operating the suction unit 23. Here, examples of the suction unit 23 include a compressor and a simple open air structure.

  According to the fourth embodiment, when the pressure sensor 11 detects that the pressure has decreased to some extent after the start of the blockage, the upstream on-off valve 21 and the downstream side respectively provided on the upstream side and the downstream side of the heat exchanger 9. Since the on-off valve 22 is closed to isolate the closed portion in a pressure-isolated state, and the suction portion 23 can be operated to apply a large suction force to the closed portion, the decomposition reaction of the gas hydrate proceeds at a stretch, and the short The decomposition reaction can be completed in time. Thereafter, the upstream side opening / closing valve 21 and the downstream side opening / closing valve 22 are returned to the open state, and the suction unit 23 is stopped, so that the normal state can be restored from the closed state in a short time.

It is a schematic block diagram which shows the manufacturing apparatus of the gas hydrate which concerns on Embodiment 1 of this invention. It is a schematic block diagram which shows the manufacturing apparatus of the gas hydrate which concerns on Embodiment 2 of this invention. It is a schematic block diagram which shows the manufacturing apparatus of the gas hydrate which concerns on Embodiment 3 of this invention. It is a schematic block diagram which shows the manufacturing apparatus of the gas hydrate which concerns on Embodiment 4 of this invention. It is a schematic block diagram which shows the manufacturing apparatus of the conventional gas hydrate.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Reaction production | generation part, 2 Liquid cooling part, 3 Dehydration apparatus, 4 High concentration secondary gas hydrate, 6 Primary gas hydrate, 7 Circulation line, 7a, 7b Flow path, 8 Circulation pump, 9 Heat exchanger, 9a, 9b heat exchanger, 10 slurry pump, 11 pressure sensor, 11a, 11b pressure sensor, 13a, 13b on-off valve, 15 first on-off valve, 17 branch flow path, 18 second on-off valve, 20 control unit, 21 upstream Side open / close valve, 21 Downstream side open / close valve, 23 Suction part

Claims (1)

A reaction generating unit that generates a gas hydrate by reacting a raw material gas and water under low temperature and high pressure;
A liquid cooling unit for cooling the liquid in the reaction generation unit,
The liquid cooling part is
A circulation line for extracting liquid from the reaction generation unit and returning it again;
A circulation pump provided in the circulation line;
A cooling unit provided in the circulation line and positioned on the upstream side in the circulation direction from the circulation pump;
A first on-off valve provided on the upstream side in the circulation direction of the cooling unit;
A pressure sensor provided between the circulation pump and the cooling unit;
A branched flow path branched from the liquid flow path in the cooling section and connected upstream of the circulation pump;
A second on-off valve provided in the branch flow path;
A control unit that performs control to close the first on-off valve and open the second on-off valve when a pressure equal to or lower than the decomposition equilibrium pressure of the gas hydrate is detected by the pressure sensor. manufacturing device.

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