JP2007262372A - Method for producing mixed gas hydrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enlarge the particle diameter of a mixed gas hydrate when producing the mixed gas hydrate by reacting a mixed gas with raw material water. <P>SOLUTION: The method for producing the mixed gas hydrate involves reacting the mixed gas g with the raw material water w. The mixed gas hydrate is produced under a condition wherein the temperature T<SB>2</SB>in a hydrate production vessel 1 is regulated so that the difference ΔT (=T<SB>1</SB>-T<SB>2</SB>) between the temperature T<SB>2</SB>and the equilibrium temperature T<SB>1</SB>may be 0-5°C. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a mixed gas hydrate, in which a mixed gas and raw material water are reacted to produce a mixed gas hydrate.

  When producing natural gas hydrate from natural gas and raw material water, the produced natural gas hydrate is dispersed in water to form a slurry. In order to increase the economy of storage and transportation of natural gas hydrate, it is preferable that the content of natural gas hydrate is high. Therefore, in general, natural gas hydrate with a high content is obtained by removing moisture in the slurry by a dehydration process. A method for producing a rate is employed (for example, see Patent Document 1).

  By the way, when the gas component is methane gas, when the particle size of methane hydrate in the slurry was measured, the average particle size was 50 to 150 μm. Thus, the dehydration property of methane hydrate having a large particle size is relatively high. Therefore, the dehydration in the dehydration process can be performed relatively easily by gravity dehydration and squeezing dehydration, and the moisture content can be 50% or less.

  However, in the case of a mixed gas hydrate composed of a mixed gas (natural gas) containing heavy components such as ethane, propane, and butane in methane, the average particle size was 10 to 50 μm. This mixed gas hydrate has a problem that the dehydration performance is low, and the throughput in the dehydration process is significantly reduced as compared with methane hydrate. When the throughput in the dehydration process is reduced, the production amount of gas hydrate in the entire apparatus is reduced. In addition, when trying to obtain an equivalent processing amount, there is a problem that the dehydrating apparatus becomes large and the apparatus cost and the operating cost increase. Furthermore, since the dehydrating property is poor, the moisture content in the gas hydrate after dehydration is still high, and there is a problem that the load of the secondary reaction step in the subsequent step increases.

  Further, if the particle size of the gas hydrate is small, even if the concentration of the gas hydrate is the same, the viscosity of the slurry becomes high and transportation becomes difficult. For this reason, there existed a problem that the stirring power of a gas hydrate slurry tank and a reactor, and pump power increased. For this reason, a high discharge pressure type pump and a powerful stirrer are required, and the cost of the apparatus increases.

Moreover, the gas hydrate having a small particle size has a strong adhesion property of the dehydrated gas hydrate and is likely to adhere to the inside of the apparatus or the pipe and close. If it is closed, steady operation becomes difficult, and there is a problem that the operation is stopped. In addition, gas hydrate with a small particle size is easily affected by the environment, the amount of decomposition in the process of taking out to atmospheric pressure after cooling to 0 ° C. or less is large, and the decomposition rate of hydrate during storage is also large, There was a problem that storage stability was bad.
JP 2003-105362 A

  An object of the present invention is to provide a method for producing a mixed gas hydrate capable of increasing the particle diameter of the mixed gas hydrate when producing the mixed gas hydrate by reacting the mixed gas and the raw water. is there.

  Another object of the present invention is to not only increase the particle diameter of the mixed gas hydrate but also improve the reaction rate when producing the mixed gas hydrate by reacting the mixed gas and the raw water. Another object is to provide a method for producing a mixed gas hydrate.

In the method for producing a mixed gas hydrate according to the first aspect of the invention, when the mixed gas hydrate is produced by reacting the mixed gas and the raw water, the temperature and pressure in the hydrate generator are The mixed gas hydrate is produced under the condition that the difference ΔT (= T ₁ −T ₂ ) between the temperature T ₂ and the equilibrium temperature T ₁ is 0 to 5 ° C. or less.

In the method for producing a mixed gas hydrate according to the invention described in claim 2, when producing the mixed gas hydrate by reacting the mixed gas and the raw water, among the temperature and pressure in the hydrate generator, The temperature T ₂ is produced in a plurality of reactors under the condition that the difference ΔT (= T ₁ −T ₂ ) from the equilibrium temperature T ₁ is within 0 to 5 ° C., and the raw material gas of the latter reactor is used. It introduce | transduces from the gaseous phase of a reactor of a front | former stage.

In the method for producing a mixed gas hydrate according to the invention of claim 3, when producing the mixed gas hydrate by reacting the mixed gas and the raw water, among the temperature and pressure in the hydrate generator, The temperature T ₂ is produced in a plurality of reactors under the condition that the difference ΔT (= T ₁ −T ₂ ) from the equilibrium temperature T ₁ is 0 to 5 ° C. P 'is made higher than the pressure P of the preceding hydrate generator to produce a mixed gas hydrate.

As described above, when the mixed gas hydrate is produced by reacting the mixed gas and the raw water, the invention according to the first aspect uses the temperature T ₂ among the temperature and pressure in the hydrate generator. Since the mixed gas hydrate is produced under the condition that the difference ΔT (= T ₁ −T ₂ ) with respect to the equilibrium temperature T ₁ is within 0 to 5 ° C., the particle size (average of the mixed gas hydrate) It was possible to increase the particle size). This makes it possible to produce a gas hydrate with good dewaterability regardless of the composition of the source gas. Also, in the case of a gas hydrate composed of a mixed gas (for example, natural gas) containing heavy components such as ethane, propane, and butane in methane, the dehydrating property is increased, and the dehydrating apparatus can be made compact. Moreover, since the water content in the gas hydrate after dehydration is low, the burden on the second reaction step in the subsequent step can be reduced.

  In addition, when the gas hydrate particle size is small, the viscosity of the slurry increases even if the gas hydrate concentration is the same, and there is a problem that the stirring power of the gas hydrate slurry tank and reactor, and the pump power increase. The slurry pump power could be reduced by about 20% by increasing the particle size of the gas hydrate. In addition, gas hydrate with a small particle size has strong adhesion to dehydrated gas hydrate and is likely to clog due to adhering to the inside of equipment and piping. However, the particle size increased and the adhesion decreased.

  Hydrate having a small particle size has a large amount of decomposition in the process of depressurization from the generation pressure to atmospheric pressure after cooling to 0 ° C. or lower. In addition, there was a problem that the decomposition rate during storage at 0 ° C. or less was large and the storage stability was poor. By increasing the particle size, the amount of decomposition in the process of depressurization from the generation pressure to atmospheric pressure and taking it out decreased, and the decomposition rate during storage at 0 ° C. or lower decreased, and the storage stability improved.

According to the second aspect of the present invention, when the mixed gas hydrate is produced by reacting the mixed gas and the raw water, the temperature T ₂ of the temperature and pressure in the hydrate generator is set to the equilibrium temperature T _1. The difference ΔT (= T ₁ −T ₂ ) is 0 to 5 ° C. and is produced in a plurality of reactors, and the raw material gas of the latter reactor is introduced from the gas phase of the former reactor. As a result, the reaction temperature and pressure can be set more finely, so that the particle size (average particle size) of the mixed gas hydrate can be increased even in the case of a mixed gas. This makes it possible to produce a hydrate with good dewaterability regardless of the composition of the source gas.

  Also, in the case of a gas hydrate composed of a mixed gas (for example, natural gas) containing heavy components such as ethane, propane, and butane in methane, the dehydrating property is increased, and the dehydrating apparatus can be made compact. Moreover, since the water content in the gas hydrate after dehydration is low, the burden on the second reaction step in the subsequent step can be reduced.

  In addition, if the particle size of the gas hydrate is small, the viscosity of the slurry becomes high even if the concentration of the gas hydrate is the same, there is a problem that the stirring power of the gas hydrate slurry tank and reactor, the pump power is increased, The slurry pump power could be reduced by about 20% by increasing the particle size of the gas hydrate. In addition, gas hydrate with a small particle size has strong adhesion to dehydrated gas hydrate and is likely to clog due to adhering to the inside of equipment and piping. However, the particle size increased and the adhesion decreased.

  Hydrate having a small particle size has a large amount of decomposition in the process of depressurization from the generation pressure to atmospheric pressure after cooling to 0 ° C. or lower. In addition, there was a problem that the decomposition rate during storage at 0 ° C. or less was large and the storage stability was poor. By increasing the particle size, the amount of decomposition in the process of depressurization from the generation pressure to atmospheric pressure and taking it out decreased, and the decomposition rate during storage at 0 ° C. or lower decreased, and the storage stability improved.

According to the third aspect of the present invention, when the mixed gas hydrate is produced by reacting the mixed gas and the raw water, the temperature T ₂ among the temperature and pressure in the hydrate generator is set to the equilibrium temperature T _1. The difference in pressure ΔT (= T ₁ −T ₂ ) is 0 to 5 ° C. or less, and is produced in a plurality of reactors, and the pressure P ′ of the subsequent hydrate generator is used to generate the hydrate in the previous stage. Since the mixed gas hydrate is produced at a pressure higher than the pressure P of the vessel, not only is the effect equivalent to that of the invention described in claim 1, but also the production speed in the case of the mixed gas is remarkably improved as compared with the prior art. It became so.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(1) First Embodiment As shown in FIG. 1, a reactor (hereinafter referred to as a generator) 1 is passed through a gas pipe 2 to a mixed gas g having a predetermined pressure P (for example, 1 to 10 MPa). In addition, the raw material water w having a predetermined temperature T ₂ is supplied through the water supply pipe 3.

Here, the water temperature T ₂ in the reactor 1 is set such that the difference ΔT (= T ₁ −T ₂ ) (also referred to as the degree of supercooling) from the equilibrium temperature T ₁ is within 0 to 5 ° C. Yes. The water temperature T ₂ in the reactor 1 is adjusted by the water temperature of the raw water w and the water temperature of the circulating water 7. Note that the gas composition used for obtaining the equilibrium temperature is not a raw material gas but a gas phase gas composition. When the difference ΔT from the equilibrium temperature T ₁ exceeds 5 ° C., the particle size of the mixed gas hydrate becomes as fine as 50 μm or less. Further, when the difference ΔT from the equilibrium temperature T ₁ is less than 0 ° C., no mixed gas hydrate is generated. Moreover, as mixed gas, the natural gas etc. which have methane as a main component can be mentioned, for example.

Here, the equilibrium temperature can be obtained as follows.
(A) Method obtained from the three-phase equilibrium diagram in the literature Literature 1) includes simple gas such as methane, ethane, propane, butane, carbon dioxide, nitrogen, hydrogen sulfide (H ₂ S),
Methane + ethane, methane + propane, methane + i-butane, methane + n-butane, methane + carbon dioxide, methane + nitrogen, methane + hydrogen sulfide, ethane + propane, ethane + carbon dioxide, propane + i-butane, propane + n-butane A three-phase equilibrium diagram of propane + carbon dioxide is described.

  The equilibrium temperature can be read from the reaction pressure from the equilibrium curve of the same gas component as the process. Fig. 3 shows the equilibrium diagram of methane + ethane. When the reactor gas phase is 97.8% methane, ethane is 2.2%, and the reaction pressure is 4.4 MPa, the equilibrium temperature is 280 K from the graph. Therefore, the reaction temperature can be set to 280K to 285K.

  FIG. 4 shows an equilibrium diagram of methane + propane. When the methane in the gas phase of the reactor is 99%, propane is 1%, and the reaction pressure is 2.0 MPa, the equilibrium temperature is 276K from the graph. Therefore, the reaction temperature can be set to 276K to 281K. The gas composition in the reactor gas phase can be obtained by extracting a part of the reactor gas and analyzing it by gas chromatography.

(B) Method of obtaining by calculation of equilibrium temperature It can be obtained by the computer program CSMHYD attached to the document 1). The analogy of the CSMHYD program is described in document 1). The equilibrium temperature can be obtained by inputting the gas phase gas composition and reaction pressure into this program.

  The gas phase gas composition to be input (gas composition in the gas phase of the reactor) can be obtained by extracting a part of the reactor gas and analyzing it by gas chromatography. Moreover, it is also possible to obtain | require by calculating repeatedly the composition in a gaseous phase used as the gas composition in the produced | generated gas hydrate by the said program.

  Reference 1) E.D. Sloan, jr .: Clathrate Hydrates of Natural Gases, Marcel Dekker, Inc., New York, (1998)

The generator 1 has two circulation paths, and the gas circulation path 4 ejects the mixed gas g in the upper space of the generator 1 from the nozzle 6 at the bottom of the generator as fine bubbles a by the blower 5. It is like that. In addition, the slurry circulation path 7 is configured so that a part of the slurry s extracted by the pump 8 is cooled by the heat exchanger 9 and returned to the generator 1. At that time, the slurry s is cooled by the heat exchanger 9 to the same temperature or lower as the liquid phase temperature (T ₂ ) in the reactor. The slurry circulation path 7 has a branch pipe 11 provided with a valve 10 between the pump 8 and the heat exchanger 9, and supplies the mixed gas hydrate slurry s to a dehydrator (not shown).

The generator 1 includes a pressure gauge 12, a thermometer 13, a water level gauge (not shown), and a stirrer 14. The pressure gauge 12 controls a first flow rate adjustment valve (not shown) provided in the gas pipe 2 so that the pressure P in the generator 1 becomes constant under a set operating condition (for example, 1 to 10 MPa). It has become. The thermometer 13 controls the flow rate of the refrigerant supplied to the heat exchanger 9 so that the water temperature T ₂ in the reactor 1 satisfies the set temperature condition. In addition, the water level meter controls a second flow rate adjustment valve (not shown) provided in the water supply pipe 3 so that the liquid level in the generator 1 is constant. On the other hand, a hydrate concentration meter (not shown) is provided in the slurry circulation path 7, and the pump 8, blower 5, stirrer 14, not shown in the drawing are adjusted so that the hydrate concentration becomes a predetermined concentration (for example, 5 to 30 wt%). 2 The flow rate adjusting valve is controlled.

Now, as shown in FIG. 1, a mixed gas g (pressure P) composed of methane, ethane, propane, and butane and raw water w are generated by a generator 1 (the water temperature T _{2 of the} generator 1 is a temperature obtained by equilibrium calculation). the difference between _{T 1 ΔT (= T 1 -T} 2) is made within 0 to 5 ° C.. supplies to), the blower 5, the pump 8, heat exchanger 9, a pressure gauge 12, the thermometer 13, When the stirrer 14, a water level meter and a hydrate concentration meter (not shown) are operated and the inside of the generator 1 is maintained at a predetermined temperature, pressure, water level, and hydrate concentration, a mixed gas hydrate having an average particle size of 50 μm can be obtained. did it.

(2) Second Embodiment As shown in FIG. 2, the first generator 1 is supplied with a mixed gas g of a predetermined pressure P (for example, 1 to 10 MPa) through a gas pipe 2 and a water supply pipe. The raw material water w having a predetermined temperature T ₂ is supplied through 3. Here, examples of the mixed gas include natural gas mainly composed of methane.

The first generator 1 has two circulation passages, and the gas circulation passage 4 allows the mixed gas g in the upper space of the first generator 1 to be finely passed from the nozzle 6 at the bottom of the first generator by the blower 5. It is designed to eject as bubbles a. In addition, the slurry circulation path 7 is configured so that a part of the slurry s extracted by the pump 8 is cooled by the heat exchanger 9 and returned to the generator 1. At that time, the slurry s is cooled by the heat exchanger 9 to a temperature equal to or lower than the temperature inside the reactor (T ₂ ). The slurry circulation path 7 has a branch pipe 11 having a valve 10 between the pump 8 and the heat exchanger 9. The branch pipe 11 is connected to a branch pipe 31 branched from the slurry circulation path 27 of the second generator 21.

The first generator 1 includes a pressure gauge 12, a thermometer 13, a water level gauge (not shown), and a stirrer 14. The pressure gauge 12 adjusts a first flow rate adjustment valve (not shown) provided in the gas pipe 2 so that the pressure P in the generator 1 becomes constant under a set operating condition (for example, 1 to 10 MPa). It has become. Further, the thermometer 13 adjusts the flow rate of the refrigerant supplied to the heat exchanger 9 so that the water temperature T ₂ in the first generator 1 satisfies the set temperature condition. Further, the water level meter adjusts a second flow rate adjustment valve (not shown) provided in the water supply pipe 3 so that the liquid level in the first generator 1 is constant. On the other hand, the slurry circulation path 7 has a hydrate concentration meter (not shown), and a blower 5, a pump 8, a stirrer 14, and an illustration are provided so that the hydrate concentration becomes a predetermined concentration (for example, 5 to 30 wt%). The second flow rate adjusting valve is not controlled.

  On the other hand, the unreacted gas g ′ having a predetermined pressure P (for example, 1 to 10 MPa) is supplied to the second generator 21 through the communication pipe 15 communicating with the first generator 1, and through the water supply pipe 23. The raw material water w having a predetermined temperature is supplied. The communication pipe 15 has a compressor 16.

Here, the water temperature T ₂ ′ in the second generator 21 has a difference ΔT ′ (= T ₁ ′ −T ₂ ′) (also referred to as supercooling degree) with the temperature T ₁ ′ obtained by the equilibrium calculation of 0. It is set to be within 5 ° C. The gas composition used for the equilibrium calculation is not the raw material gas but the gas composition of the gas phase of the second generator. When the difference ΔT ′ from the temperature T ₁ ′ obtained by the equilibrium calculation exceeds 5 ° C., the particle size of the mixed gas hydrate becomes as fine as 50 μm or less. Further, when the difference ΔT ′ from the temperature T ₁ ′ obtained by the equilibrium calculation is less than 0 ° C., the mixed gas hydrate is not generated.

The second generator 21 has two circulation paths, and the gas circulation path 24 finely removes the unreacted gas g ′ in the upper space of the second generator 21 from the nozzle 26 at the bottom of the generator by the blower 25. It is designed to eject as bubbles a. In addition, the slurry circulation path 27 is configured so that a part of the slurry s extracted by the pump 28 is cooled by the heat exchanger 29 and returned to the second generator 21. At that time, the slurry s is cooled by the heat exchanger 29 to the second generator internal liquid temperature (T ₂ ′) or lower. The slurry circulation path 27 has a branch pipe 31 having a valve 30 between the pump 28 and the heat exchanger 20, and supplies the mixed gas hydrate slurry s to a dehydrator (not shown).

The second generator 21 includes a pressure gauge 32, a thermometer 33, a water level gauge (not shown), and a stirrer 34. The pressure gauge 32 controls the compressor 16 so that the pressure P ′ in the second generator 21 becomes constant under the operating condition (for example, 1 to 10 MPa) set. In addition, the thermometer 33 adjusts the flow rate of the refrigerant supplied to the heat exchanger 29 so that the water temperature T ₂ ′ in the second generator 21 satisfies the set temperature condition. Further, the water level meter adjusts a third flow rate adjustment valve (not shown) provided in the water supply pipe 23 so that the liquid level in the second generator 21 is constant. On the other hand, the slurry circulation path 27 has a hydrate concentration meter (not shown), and a stirrer 34, a blower 25, a pump 28, and an illustration are provided so that the hydrate concentration becomes a predetermined concentration (for example, 5 to 30 wt%). The third flow rate adjusting valve is not controlled.

Now, as shown in FIG. 2, a mixed gas g (pressure P) composed of methane, ethane, propane, and butane and raw material water w are mixed with the first generator 1 (the liquidus temperature T ₂ of the first generator 1 is The difference ΔT (= T ₁ −T ₂ ) from the temperature T ₁ obtained by the equilibrium calculation is within 0 to 5 ° C.), and the blower 5, pump 8, heat exchanger 9, pressure gauge 12, the thermometer 13, the stirrer 14, the water level meter and the hydrate concentration meter (not shown) are operated to maintain the predetermined temperature, pressure, water level, and hydrate concentration in the first generator 1, and at the same time, the second generator 21 Is supplied to the second generator 21, and the blower 25, pump 28, heat exchanger 29, pressure gauge 32, thermometer 33, stirrer 34, water level meter and hydrate concentration meter (not shown) are operated. The inside of the second generator 21 is at a predetermined temperature (the liquid of the second generator 1 The phase temperature T ₂ ′ has a difference ΔT ′ (= T ₂ ′ −T ₁ ′) from the temperature T ₁ ′ obtained by equilibrium calculation within 0 to 5 ° C.), pressure, water level, hydrate The concentration was controlled to be maintained. Further, when the compressor 16 was controlled to be slightly higher than the pressure P of the unreacted gas g ′, the production amount of the mixed gas hydrate slurry s increased.

Example 1
A half amount of raw water was put into a reactor (generator) having an internal volume of 25 L shown in FIG. 1, and hydrate was produced under the following conditions.

1) Since gas was consumed as hydrate generation progressed, the raw material gas was supplied so that the pressure P in the reactor would be constant under the determined operating conditions.
2) The hydrate concentration in the reactor was controlled to 30%.
3) The produced hydrate slurry is supplied to the dehydrator at a constant flow rate. Since the liquid level in the reactor was lowered by the supply, the raw water was replenished so that the liquid level was constant.

  The results are shown in “Table 1”. It can be seen from “Table 1” that according to the method of the present invention, a mixed gas hydrate having an average particle diameter of 50 μm can be obtained. Here, No. 1 is a reference example, No. 2 is the present invention, and No. 3 is a comparative example. The pump power of the circulating water was reduced from 2.0 kW to 1.7 kW.

  Moreover, the dehydrating property in the dehydrator was improved, and the load on the post-process was reduced. In addition, the adhesion was reduced, and the trouble of clogging was reduced. The 30 μm hydrate having a small particle size was cooled to 0 ° C. or lower, and the pressure was reduced from the generation pressure to the atmospheric pressure. According to the present invention, the particle size was 50 μm, and the amount of decomposition was 61% for the particles alone, which reduced the amount of decomposition by 20%.

  The decomposition rate during storage at −20 ° C. was 0.52% / s (the rate after storage for 1 hour) of the hydrate having a small particle size of 30 μm. According to the present invention, the particle size was 50 μm, the decomposition rate during storage was 0.38% / s (the rate after 1 hr of storage), and the 30% decomposition rate could be reduced. It was confirmed that the amount of decomposition during the process of reducing the pressure from the generation pressure to atmospheric pressure and taking it out decreased, the decomposition rate during storage at 0 ° C. or lower was reduced, and the storage stability was improved.

(Example 2)
A half amount of raw water was put into each of the first reactor and the second reactor each having an internal volume of 25 L shown in FIG. 2 to produce a hydrate under the following conditions.

1) Since gas was consumed as hydrate generation progressed, the raw material gas was supplied so that the pressure P in the reactor would be constant under the determined operating conditions.
2) The hydrate concentration in the reactor was controlled to 30%.
3) The produced hydrate slurry is supplied to the dehydrator at a constant flow rate. Since the liquid level in the reactor was lowered by the supply, the raw water was replenished so that the liquid level was constant.

  The results are shown in “Table 2”. From “Table 2”, according to the method of the present invention, a mixed gas hydrate having an average particle diameter of 80 μm is obtained in the second reactor.

  In the present invention, since the gas composition of the first generator is supplied to the second generator, the gas composition of the second generator becomes rich in methane gas, so that the equilibrium pressure of the second generator is shifted to the higher one. To do. For this reason, the pressure of the second generator can be increased even under the condition of the degree of supercooling of 0 to 5 ° C., the hydrate production amount of the second generator is 12 kg / hr, and the total production amount is 18 kg. / Hr.

  When the raw material gas is supplied side by side under the same conditions as the first generator, or when the hydrate is manufactured with the 50L first generator whose volume is double, the hydrate manufacture of the first generator The production amount is 12 kg / hr, twice the amount of 6 kg / hr. Therefore, the production rate of hydrate increased by 50% according to the method of claim 3. Moreover, since the particle size was increased, the viscosity of the slurry was lowered, and the power of the circulating water pump was 4 kW in the past. However, in the present invention, the total power is 3.3 kW, and 21% of the power is reduced . Not only the circulation pump but also the power of the agitator and dehydrator could be reduced by 20%.

  Moreover, the dehydrating property in the dehydrator was improved, and the load on the post-process was reduced. In addition, the adhesion was reduced, and the trouble of clogging was reduced. The 30 μm hydrate having a small particle size was cooled to 0 ° C. or lower, and then the pressure was reduced from the generation pressure to the atmospheric pressure. According to the present invention, the particle size was 50 to 80 μm, and the amount of decomposition was 53% with the particles alone, which reduced the amount of decomposition by 30%.

  The decomposition rate at the time of storage at −20 ° C. was 0.52% / s (the rate after 1 hr after storage) of the hydrate having a small particle size of 30 μm. According to the present invention, the particle size was 50 μm to 80 μm, and the decomposition rate during storage was 0.31% / s (the rate after 1 hr of storage), and the 40% decomposition rate could be reduced. It was confirmed that the amount of decomposition during the process of reducing the pressure from the generation pressure to atmospheric pressure and taking it out decreased, the decomposition rate during storage at 0 ° C. or lower was reduced, and the storage stability was improved.

It is a schematic block diagram which shows the 1st embodiment of the manufacturing method of the gas hydrate of this invention. It is a schematic block diagram which shows the 1st embodiment of the manufacturing method of the gas hydrate of this invention. It is an equilibrium diagram of methane + ethane. It is an equilibrium diagram of methane + propane.

Explanation of symbols

g Mixed gas w Raw material water 1 Hydrate generator

Claims (3)

Upon mixing gas and raw water and are reacted to produce a mixed gas hydrate, among the temperature and the pressure in the hydrate generator, the temperature T _2, the difference between the equilibrium temperature T ₁ ΔT (= T ₁ - A method for producing a mixed gas hydrate, comprising producing a mixed gas hydrate under a condition that T ₂ ) is within 0 to 5 ° C. Upon mixing gas and raw water and are reacted to produce a mixed gas hydrate, among the temperature and the pressure in the hydrate generator, the temperature T _2, the difference between the equilibrium temperature T ₁ ΔT (= T ₁ - A mixed gas hydrate produced under the conditions that T ₂ ) is within 0 to 5 ° C. and produced in a plurality of reactors, and the raw material gas of the latter reactor is introduced from the gas phase of the former reactor Rate production method. Upon mixing gas and raw water and are reacted to produce a mixed gas hydrate, among the temperature and the pressure in the hydrate generator, the temperature T _2, the difference between the equilibrium temperature T ₁ ΔT (= T ₁ - T ₂ ) is produced in a plurality of reactors under the condition of 0 to 5 ° C., and the pressure P ′ of the latter hydrate generator is set higher than the pressure P of the former hydrate generator. A method for producing a mixed gas hydrate, comprising producing a mixed gas hydrate.

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