WO2022000891A1 - Hydrate evaluation experiment system and method - Google Patents

Abstract

Disclosed are a hydrate evaluation experiment system and a method therefor. The evaluation experiment system comprises a first gas cylinder (1), a second gas cylinder (2), a flow control device, a flow controller (12), a magnetic stirring vessel (63), a chemical reagent injection device, and a closed loop, wherein the first gas cylinder (1) is used for storing CH₄ or a natural-gas mixed gas; a gas outlet of the first gas cylinder (1) is connected to the magnetic stirring vessel (63) via the flow controller (12); the second gas cylinder (2) is used for storing CO₂ gas; a gas outlet of the second gas cylinder (2) is connected to the magnetic stirring vessel (63) via the flow control device; a chemical reagent injection port is provided on the magnetic stirring vessel (63), and the chemical reagent injection port is connected to an outlet of the chemical reagent injection device; and the closed loop is respectively connected to the first gas cylinder (1), the second gas cylinder (2) and the chemical reagent injection device by means of a twentieth valve (42). According to the invention, hydrate formation can be simulated, and the influence on the hydrate formation and decomposition rules is also analyzed, facilitating the conduction of further detailed analysis and research, thereby guiding production.

Description

A kind of hydrate evaluation experiment system and method technical field

The invention relates to the field of hydrate development, in particular to a hydrate evaluation experiment system and method.

Background technique

Natural gas hydrate is a naturally occurring compound with a cage-like structure. It is an efficient and clean energy source with high combustion calorific value. Its combustion produces dozens of times more energy than ordinary fossil fuels of the same quality. Natural gas hydrate is a clathrate crystalline compound formed by small molecules of light hydrocarbon gases such as methane and water molecules in natural gas under certain temperature and pressure conditions, which is similar in appearance to loose ice or dense snow.

With the further in-depth study of it, many mining methods have been proposed. The main principle is to change the temperature and pressure of the combustible ice reservoir, break its phase balance, and decompose the combustible ice to obtain methane gas. In the process of natural gas extraction, storage and transportation, natural gas hydrate often causes blockage of pipelines, valves and equipment. Although there are many methods to prevent natural gas hydrate, there are currently five methods to prevent natural gas hydrate embolism in pipelines: dehydration method, decompression method method, heating method, mechanical method, chemical method.

Studies have shown that chemical methods generally inject chemical reagents (such as methanol, etc.) into the formation, which is the most common and effective method. It can improve the phase equilibrium conditions for the formation of hydrates, so that the pore pressure and temperature conditions of the formation cannot meet the requirements of hydrates. The phase equilibrium, so that the hydrate decomposition phase transition produces methane gas which is collected by the method. Chemical methods can not only inhibit the formation of natural gas hydrates, but also dissolve the formed natural gas hydrates.

The existing experimental systems for the synthesis and exploitation of hydrates have the following shortcomings: (1) The research objects are mainly aimed at natural gas hydrates, and few are aimed at CO ₂ hydrates. (2) There are no studies on the properties of hydrate inhibitors and accelerators. (3) When the corresponding gas and liquid are output, the design of the pressure control is relatively simple, especially in the decompression decomposition experiment, the output pressure is not stable enough, and there may be pulses, which affects the accuracy of measurement and the experimental effect. (4) After the formation of combustible ice, the measurement of the specific distribution of internal temperature and pressure is not accurate enough, and the precision is not enough, which brings inconvenience to experimental research. (5) Some equipment still has hidden safety hazards or inconvenient operation, which cannot better control the experimental process, which brings great inconvenience to the development of experimental research. (6) The embolism of natural gas hydrate in the pipeline and the corresponding preventive measures are not studied.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a hydrate evaluation experiment system and method, which solves the above-mentioned defects in the existing hydrate synthesis and mining research experiments.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A hydrate evaluation experimental system provided by the present invention includes a first gas cylinder, a second gas cylinder, a flow control device, a flow controller, a magnetic stirring vessel, a chemical reagent injection device and a closed loop, wherein,

A first cylinder for storing gas or a mixed gas of CH _4; outlet gas of the first cylinder through the flow controller connected to a magnetic stirring vessel;

A second for storing the CO ₂ gas cylinder; the second cylinder through the gas outlet flow rate control means connected to the magnetic stirring vessel;

The magnetic stirring vessel is provided with a chemical reagent injection port, and the chemical reagent injection port is connected to the outlet of the chemical reagent injection device;

The closed loop is respectively connected with the first gas cylinder, the second gas cylinder and the chemical reagent injection device through the twentieth valve.

Preferably, the closed circuit includes a third pressure gauge, a first thermometer, a window, a twenty-second valve, a differential pressure sensor, a twenty-third valve, a twenty-fourth valve, a twenty-fifth valve, a circulation pump, and The twenty-sixth valve, wherein the outlet of the twentieth valve is connected to the inlet of the window, the outlet of the window is respectively connected to the twenty-second valve and the twenty-fourth valve, and the outlets of the twenty-second valve are sequentially After the differential pressure sensor and the twenty-third valve are combined with the outlet of the twenty-fourth valve, they are respectively connected to the twenty-fifth valve and the inlet of the circulating pump, the outlet of the circulating pump is connected to the second through the twenty-sixth valve. The outlets of the fifteen valves are merged and then connected to the inlets of the windows.

Preferably, the outlets of the first gas cylinder and the second gas cylinder are connected to a high-pressure storage tank through a gas booster pump, and the outlets of the high-pressure storage tank are respectively connected to a flow controller and a flow control device.

Preferably, the air inlet of the gas booster pump is connected to a low-pressure storage tank through a tenth valve, and the low-pressure storage tank is connected to an air compressor.

Preferably, the low-pressure storage tank is also connected with a chemical reagent injection device.

Preferably, the flow control device includes a first liquid pool, a first piston and a second piston, wherein the liquid outlet of the first liquid pool passes through the constant pressure pump and the liquid inlet of the first piston and the second piston respectively. The ports are connected; the gas outlets of the first piston and the second piston are respectively connected to the magnetic stirring vessel through the seventh valve and the eighth valve.

Preferably, the chemical reagent injection device includes a second liquid pool, a third piston and a fourth piston, wherein the liquid outlet of the second liquid pool is connected to the liquid inlets of the third piston and the fourth piston respectively through a constant flow pump Connection; the chemical reagent outlets of the third piston and the fourth piston are connected to the twentieth valve through the sixteenth valve and the eighteenth valve, respectively.

Preferably, the experimental system further includes an exhaust device for evacuation, the exhaust device includes a twenty-seventh valve, the twenty-seventh valve is arranged on the closed circuit, and the twenty-seventh valve is The outlet is respectively connected to a buffer tank and a vacuum pump, and the buffer tank is provided with a fourth pressure gauge and a twenty-eighth valve.

Preferably, the experimental system further includes a gas-liquid separation structure, the gas-liquid separation structure includes a gas-liquid separator, and the inlet of the gas-liquid separator is connected to the outlet of the magnetic stirring vessel through the back pressure valve and the twenty-ninth valve in sequence. ; The gas outlet of the gas-liquid separator is connected to a wet flow meter; the liquid outlet of the gas-liquid separator is connected to a metering container.

A hydrate evaluation experimental method, based on the hydrate evaluation experimental system, comprises the following steps:

According to the purpose of the experiment, choose one of the four cases A, B, C, and D to carry out the experiment:

A: When the synthesis of hydrate is carried out without chemical reagents, among them, the synthesis of combustible ice:

After stored in a first or a CH ₄ gas cylinder of pressurized gas mixture, the flow through the controller into the vessel with magnetic stirring, the experimental parameters set in accordance with the experimental procedure required, for the synthesis of combustible ice;

Synthesis of CO ₂ hydrate:

After stored in the second pressurized CO ₂ gas cylinder, a magnetic stirring directly into the vessel, the experimental parameters set in accordance with the experimental procedure required, CO ₂ hydrate synthesis;

B: When chemical reagents are used to synthesize hydrates, among which, combustible ice is synthesized:

After stored in a first or a CH ₄ gas cylinder of pressurized gas mixture, the flow through the controller into the vessel with magnetic stirring; the same time, the use of a chemical agent injection means injection Chemicals magnetic agitator container, following the experimental process requirements Set the experimental process parameters to synthesize combustible ice;

Synthesis of CO ₂ hydrate:

After storage directly into the second cylinder in the pressurized CO ₂ gas in the vessel with magnetic stirring; the same time, the use of a chemical agent injection means injection Chemicals magnetic agitator container, the experimental parameters set following the experimental process requirements, Synthesis of CO _{2 hydrate;}

C: Test chemical reagents:

The chemical reagent is injected into the closed loop through the chemical reagent injection device, the flow speed of the liquid is set, and the circulating pump is started to make the chemical reagent flow in the closed loop; Difference;

D: Observe the synthesis or decomposition of hydrates

The CO ₂ gas or CH ₄ is sent into the closed loop through the twentieth valve, and the experimental temperature is set by the temperature control device set on the closed loop to simulate the CO ₂ gas or CH ₄ in the pipeline transportation process, due to cooling. Hydrate is formed, and when the temperature rises, whether a hydrate plug is formed in the valve and the narrow and long pipeline; and it is used to simulate the chemical removal of the hydrate plug in the circulation pipeline.

Compared with the prior art, the beneficial effects of the present invention are:

The hydrate evaluation experimental system provided by the present invention has the following advantages compared with the existing similar experimental equipment:

(1) The research object can be either natural gas or CO ₂ hydrate.

(2) The present invention can conduct research on properties such as friction of hydrate inhibitors and accelerators.

(3) When the corresponding gas and liquid are output, the control of the pressure is relatively stable, and there is no pulse, so that the accuracy of measurement and the experimental effect are guaranteed.

(4) When natural gas is transported through pipelines, it is easy to form hydrates, which often cause blockage of pipelines, valves and equipment. This system can be used to study natural gas hydrate embolism in pipelines, and preventive measures, including solutions for injecting chemical reagents.

Further, the system is designed with a back pressure valve, which can stabilize the output pressure during the depressurization experiment.

The invention is suitable for _{the relevant experimental tests of natural gas hydrate and CO 2} hydrate, and introduces relevant experimental operation methods. This experimental system can simulate the formation of hydrate, and simulate the extraction of combustible ice by depressurization method, heating method and chemical method, and evaluate the influence of temperature, pressure, type and concentration of chemical reagents, reaction time and other related factors on the extraction of combustible ice. At the same time, the test system can be used to test the properties of hydrate inhibitor samples under different temperature, pressure, flow rate and other test conditions; at the same time, its influence on the formation and decomposition of hydrate can be analyzed, which is convenient for further detailed analysis and research, so as to guide Production.

Description of drawings

FIG. 1 is a schematic structural diagram of the experimental system involved in the present invention.

detailed description

The present invention will be described in further detail below with reference to the accompanying drawings.

As shown in Figure 1, a hydrate evaluation experimental system provided by the present invention includes a first gas cylinder 1, a second gas cylinder 2, a first valve 3, a second valve 4, a gas booster pump 5, a first safety Valve 6, high pressure storage tank 7, first pressure gauge 8, pressure regulating valve 9, second pressure gauge 10, third valve 11, flow controller 12, fourth valve 13, fifth valve 14, first liquid pool 15 , constant pressure pump 16, sixth valve 17, first piston 18, seventh valve 19, eighth valve 20, second piston 21, ninth valve 22, back pressure valve 23, tenth valve 24, air compressor 25 , low pressure storage tank 26, second safety valve 27, eleventh valve 28, twelfth valve 29, thirteenth valve 30, cleaning container 31, fourteenth valve 32, second liquid pool 33, constant flow pump 34 , the fifteenth valve 35, the third piston 36, the sixteenth valve 37, the seventeenth valve 38, the fourth piston 39, the eighteenth valve 40, the nineteenth valve 41, the twentieth valve 42, the third pressure Gauge 43, first thermometer 44, first camera 45, window 46, first cold light source 47, twenty-first valve 48, twenty-second valve 49, differential pressure sensor 50, twenty-third valve 51, second The fourteenth valve 52, the third safety valve 53, the twenty-fifth valve 54, the circulation pump 55, the twenty-sixth valve 56, the vacuum pump 57, the buffer tank 58, the fourth pressure gauge 59, the twenty-seventh valve 60, the first The twenty-eighth valve 61, the thirty-second valve 62, the magnetic stirring vessel 63, the high and low temperature bath 64, the second cold light source 65, the second camera 66, the second thermometer 67, the twenty-ninth valve 68, the thirtieth valve 69. Back pressure valve 70, back pressure container 71, back pressure pump 72, fifth pressure gauge 73, wet flow meter 74, gas-liquid separator 75, thirty-first valve 77 and measuring container 78, wherein the first gas The gas outlets of the bottle 1 and the second gas bottle 2 are connected to the air inlets of the gas booster pump 5, and the gas outlets of the gas booster pump 5 are respectively connected to the high pressure storage tank 7 and the low pressure storage tank 26.

A first valve 3 is arranged between the first gas cylinder 1 and the gas booster pump 5 .

A second valve 4 is arranged between the second gas cylinder 2 and the gas booster pump 5 .

A tenth valve 24 is provided between the gas booster pump 5 and the low-pressure storage tank 26 , and power is provided to the gas booster pump 5 through the tenth valve 24 .

The high-pressure storage tank 7 is provided with a first safety valve 6 and a first pressure gauge 8 .

The high-pressure storage tank 7 passes through the pressure regulating valve 9 , the fifth valve 14 and the back pressure valve 23 in sequence.

A second pressure gauge 10 is arranged between the pressure regulating valve 9 and the fifth valve 14 .

A flow controller 12 is arranged between the air inlet of the fifth valve 14 and the air inlet of the back pressure valve 23 , and a third valve 11 is arranged at the inlet of the flow controller 12 . A fourth valve 13 is provided at the air outlet of 12 .

The outlet of the fifth valve 14 is provided with a seventh valve 19 and a ninth valve 22 in sequence, wherein the outlet of the seventh valve 19 is connected to the first piston 18 and the sixth valve 17 in sequence; the outlet of the ninth valve 22 The second piston 21 and the eighth valve 20 are connected in sequence.

The outlets of the sixth valve 17 and the eighth valve 20 are both connected with a constant pressure pump 16 , and the constant pressure pump 16 is connected with the first liquid pool 15 .

The outlet of the back pressure valve 23 is connected to the inlet of the magnetic stirring vessel 63 through the thirty-second valve 62 .

The magnetic stirring vessel 63 is arranged in a high and low temperature bath 64 , and a second cold light source 65 and a second camera 66 are arranged on the high and low temperature bath 64 .

The outlet of the magnetic stirring vessel 63 is connected to the back pressure valve 70 through the second thermometer 67 , the twenty-ninth valve 68 and the thirtieth valve 69 in sequence.

The outlets of the back pressure valve 70 are respectively connected to the back pressure container 71 and the gas-liquid separator 75 .

A wet flow meter 74 is provided at the gas outlet of the gas-liquid separator 75 .

The liquid outlet of the gas-liquid separator 75 is connected to the metering container 77 through the low thirty-one valve 76 .

An air compressor 25 is connected to the air inlet provided on the low-pressure storage tank 26 .

The low pressure storage tank 26 is provided with a second safety valve 27 and an eleventh valve 28 .

The gas outlets on the low-pressure storage tank 26 are respectively connected to the twelfth valve 29 and the thirteenth valve 30, wherein the outlet of the thirteenth valve 30 is connected to the cleaning container 31 and the fourteenth valve 32 in turn; the The outlets of the fourteenth valve 32 and the twelfth valve 29 are both connected to the inlet of the nineteenth valve 41 . The cleaning liquid in the cleaning container 31 is pressed into the subsequent pipeline system by the air pressure in the low-pressure storage tank 26, and the solid particles in the pipeline are displaced by the gas at the same time.

The sixteenth valve 37 and the eighteenth valve 40 are provided at the inlet of the nineteenth valve 41, wherein the outlet of the sixteenth valve 37 is connected to the third piston 36 and the fifteenth valve 35 in sequence; The outlet of the eighth valve 40 is connected to the fourth piston 40 and the seventeenth valve 38 in turn; the outlets of the fifteenth valve 35 and the seventeenth valve 35 are connected to the constant flow pump 34, and the outlet of the constant flow pump 34 is connected to the seventh valve. Two-liquid pool 33 .

The outlet of the nineteenth valve 41 is connected to the inlet of the twentieth valve 42,

The outlet of the twentieth valve 42 is connected to a closed circuit, and the closed circuit includes a window 46 , a twenty-second valve 49 , a differential pressure sensor 50 , a twenty-third valve 51 , a twenty-fourth valve 52 , and a twenty-fourth valve 52 . The five valves 54, the circulating pump 55, the twenty-sixth valve 56 and the thirtieth valve 69, the outlet of the chemical reagent injection device is connected to the inlet of the window 46, and the outlet of the window 46 is connected to the twenty-second valve 49 and the thirtieth valve 69, respectively. The twenty-fourth valve 52, the outlet of the twenty-second valve 49 passes through the differential pressure sensor 50 and the twenty-third valve 51 in turn and merges with the outlet of the twenty-fourth valve 52, and then is respectively combined with the twenty-fifth valve 54 It is connected to the inlet of the circulation pump 55 , the outlet of the circulation pump 55 is merged with the outlet of the twenty-fifth valve 54 through the twenty-sixth valve 56 , and then connected to the inlet of the window 46 .

A third pressure gauge 43 and a first thermometer 44 are sequentially arranged between the outlet of the twentieth valve 42 and the viewing window 46 .

The viewing window 46 is provided with a first camera 45 and a first cold light source 47 ; the first cold light source 47 can emit light to illuminate the viewing window 46 , so that the first camera 45 can capture internal experimental phenomena.

The closed loop is also provided with a twenty-first valve 48, which is used for venting when cleaning the experimental pipeline to remove residual liquid and the like.

A third safety valve 53 is designed between the twenty-fourth valve 52 and the twenty-fifth valve 54 .

The thirtieth valve 69 is connected between the closed circuit and the back pressure valve 70 .

The closed circuit is also provided with an exhaust device for evacuation, the exhaust device includes a twenty-seventh valve 60, and the outlet of the twenty-seventh valve 60 is connected to the buffer tank 58 and the vacuum pump 57 respectively. The buffer tank 58 is provided with a fourth pressure gauge 59 and a twenty-eighth valve 61 .

The magnetic stirring vessel 63 and the high and low temperature bath 64 are made of transparent materials.

A second cold light source 65 and a second camera 66 are arranged on the outside of the high and low temperature bath 64. The second cold light source 65 can illuminate the interior of the high and low temperature bath 64, which is convenient for the second camera 66 to capture internal experimental phenomena.

The inner reservoir of the first gas cylinder 1 has enough CH ₄ or natural gas mixed gas; the inner reservoir of the second gas cylinder 2 has enough CO ₂ gas.

The pressure regulating valve 9 can adjust the output gas pressure; the flow controller 12 can adjust the flow rate of the output gas, and this branch is selected when natural gas is output.

Both the first liquid pool 15 and the second liquid pool 33 have sufficient fresh water reservoirs.

_{When the CO 2} gas is output from the second gas cylinder 2 , the first piston 18 is replaced by the constant pressure pump 16 to deliver clean water, and the CO ₂ gas inhaled by the second piston 21 is output through the back pressure valve 23 .

The cleaning container 31 can be opened for storing clean water or cleaning agent for synthesizing hydrate or cleaning equipment pipelines. The tops of the third piston 36 and the fourth piston 39 are used to store chemical reagent test samples.

The rotating speed of the magnetic stirring vessel 63 can be adjusted, and the wet flow meter 74 can measure the quality of the gas flowing through. The gas-liquid separator 75 can separate the passing gas-liquid fluid. The measuring container 77 can measure the weight of the liquid separated inside.

All the connecting pipelines of the system are 316L pipelines to prevent the corrosion of the pipelines by the internal fluid, and the pipelines are wrapped with thermal insulation materials to prevent the local temperature from decreasing, which may cause the secondary generation of hydrates or the generation of ice, which may block the pipelines. This will affect the effect of the experiment and cause potential safety hazards to the experiment. The parameters such as displacement, temperature and pressure can all be collected through the data collection control card for real-time monitoring and data collection of the flow, temperature and pressure in the experimental system.

The chemical reagents of the present invention include hydrate inhibitors or hydrate accelerators.

The test method is as follows:

(1) As shown in the figure, clean the equipment, check the air tightness of the system, and adjust the relevant valves.

(2) Then turn on the vacuum pump 57 to evacuate the air inside the experimental system and the pipeline, so as to discharge the interference of the air to the experiment and prepare for the experiment.

(3) Boosting: Turn on the air compressor to provide sufficient power for the gas booster pump 5 .

(4) Start the experiment: start the experiment in the following four cases: A, B, C, and D

A. Synthesis of hydrates without chemical reagents

The twentieth valve 42 and the twenty-ninth valve 68 are closed.

To synthesize combustible ice:

13, after opening the first valve 3, the third valve and the fourth valve 11 closed fifth valve 14, the CH ₄ or natural gas stored in the gas mixture in the first cylinder 1, through a gas booster pump 5 for pressurizing, It is sent into the high-pressure storage tank 7 for storage, and the pressure of the high-pressure storage tank 7 is collected by the first pressure gauge 8, and the pressure is released through the first safety valve 6 to ensure safety.

The high-pressure gas in the high-pressure storage tank 7 is pressure-regulated by the pressure-regulating valve 9, its pressure is measured by the second pressure gauge 10, and sent to the back pressure valve through the third valve 11, the flow controller 12 and the fourth valve 13 23 to adjust the pressure, and then send it into the magnetic stirring vessel 63, set the experimental process parameters according to the experimental process requirements, and carry out the synthesis of combustible ice.

Separation of mixed gas:

The mixed gas is passed through the magnetic stirring vessel 63 , and the experimental process parameters are set according to the experimental process requirements to synthesize the hydrate; the remaining gas is passed through the gas-liquid separator 75 .

The wet flow meter 74 is used to measure the quality of the gas separated by the gas-liquid separator 75 .

The mass of the separated liquid is metered by the metering container 77 .

Synthesis of CO ₂ hydrate:

Open the second valve 4, the fifth valve 14, the sixth valve 17, the seventh valve 19, the eighth valve 20 and the ninth valve 22, close the third valve 11 and the fourth valve 1, and store in the second gas cylinder 2 the CO ₂ gas therein, through a gas booster pump 5 for pressurization, then into the high pressure receiver 7 for storage, and high-pressure collecting tank 7 through a first pressure gauge 8, performed by a first discharge valve 6 pressure to ensure safety.

The high-pressure gas in the high-pressure storage tank 7 is pressure-regulated by the pressure-regulating valve 9, the pressure is measured by the second pressure gauge 10, and then sent to the fifth valve 14, the constant-pressure pump 16 is turned on, and the gas in the first liquid pool 15 is regulated. The clean water is sent to the first piston 18 and the second piston 21 to measure CO ₂ gas while ensuring _{the quantitative injection of CO 2} special phase gas; then it is sent to the back pressure valve 23 to adjust the pressure, and then sent to the magnetic stirring In the container 63, the experimental process parameters are set according to the experimental process requirements, and the synthesis of _{CO 2 hydrate is carried out.} Same as above, and finally the separation effect under different experimental conditions was tested with the gas-liquid separation structure.

B. When chemical reagents are used to synthesize hydrates, wherein, the synthesis of combustible ice:

Send CH ₄ into the magnetic stirring vessel 63; at the same time, use the chemical reagent injection device to inject the chemical reagent into the magnetic stirring vessel 63, set the experimental process parameters according to the experimental process requirements, and carry out the synthesis of combustible ice; the same as above, and finally use gas-liquid The separation structure tests the separation effect under different experimental conditions.

Synthesis of CO ₂ hydrate:

The CO _{2 is} fed into the magnetic stirring vessel 63 ; meanwhile, the chemical reagent is injected into the magnetic stirring vessel 63 by the chemical reagent injection device, and the experimental process parameters are set according to the experimental process requirements, and the synthesis of _{CO 2 hydrate is carried out.}

Use of the chemical reagent injection device: turn on the second constant pressure pump 34, inject the clean water in the second liquid pool 33 into the third piston 36 and the fourth piston 39, and inject the chemical reagent stored on the top of the piston into the magnetic stirring container through the piston within 63.

Same as above, and finally the separation effect under different experimental conditions was tested with the gas-liquid separation structure.

C. Test chemical reagents:

The chemical reagent is injected into the window 46 through the chemical reagent injection device, the twentieth valve 42, the twenty-fifth valve 54 and the thirtieth valve 69 are closed; the twenty-second valve 49, the twenty-third valve 51 and the twentieth valve are opened. Four valves 52, set the flow rate of the liquid, start the circulation pump 55, so that the chemical reagent passes through the window 46, the twenty-fourth valve 52, the circulation pump 55, and then returns to the window 46, and flows in the closed loop formed to carry out Experimental evaluation of thermodynamic chemical reagents, kinetic chemical reagents, polymerization inhibitors or composite chemical reagents; at the same time, the differential pressure at the inlet and outlet of the twenty-fourth valve 52 is collected by the differential pressure sensor 50 .

D. Observe the synthesis or decomposition of hydrates

The CO ₂ gas or CH ₄ is sent into the closed loop through the twentieth valve 42, and the experimental temperature is set by the temperature control device set on the closed loop to simulate the CO ₂ gas or CH ₄ in the pipeline transportation process. When the temperature is lowered, hydrate is formed, and when the temperature rises, whether a hydrate plunger is formed in the valve and the narrow and long pipeline; it can also be used to simulate the chemical removal of the hydrate plunger in the circulation pipeline. Finally, the gas-liquid mixture is passed through the thirtieth valve 69 through the gas-liquid separation structure to test the separation effect under different experimental conditions.

Claims (10)

1. A hydrate evaluation experiment system, characterized in that it comprises a first gas cylinder (1), a second gas cylinder (2), a flow control device, a flow controller (12), a magnetic stirring vessel (63), a chemical reagent injection devices and closed loops where,

   The first cylinder (1) for storing gas or a mixed gas of CH _4; the first cylinder (1) through a gas flow controller outlet (12) connecting magnetic stirring vessel (63);

   The second cylinder (2) for storing the CO ₂ gas; means the second connecting magnetic cylinder (2) through the gas outlet flow control mixing container (63);

   The magnetic stirring vessel (63) is provided with a chemical reagent injection port, and the chemical reagent injection port is connected to the outlet of the chemical reagent injection device;

   The closed circuit is respectively connected with the first gas cylinder (1), the second gas cylinder (2) and the chemical reagent injection device through the twentieth valve (42).
2. A hydrate evaluation experimental system according to claim 1, characterized in that, the closed loop comprises a third pressure gauge (43), a first thermometer (44), a window (46), a twenty-second valve (43). 49), differential pressure sensor (50), twenty-third valve (51), twenty-fourth valve (52), twenty-fifth valve (54), circulating pump (55) and twenty-sixth valve (56) ), wherein the outlet of the twentieth valve (42) is connected to the inlet of the window (46), and the outlet of the window (46) is respectively connected to the twenty-second valve (49) and the twenty-fourth valve (52) , the outlet of the twenty-second valve (49) passes through the differential pressure sensor (50) and the twenty-third valve (51) in turn and merges with the outlet of the twenty-fourth valve (52), and then merges with the twenty-fifth valve (52) respectively. The valve (54) is connected with the inlet of the circulation pump (55), the outlet of the circulation pump (55) is merged with the outlet of the twenty-fifth valve (54) through the twenty-sixth valve (56), and then connected to the window (46) ) entrance.
3. A hydrate evaluation experimental system according to claim 1, characterized in that, the outlets of the first gas cylinder (1) and the second gas cylinder (2) are connected to high pressure through a gas booster pump (5). A storage tank (7), the outlet of the high-pressure storage tank (7) is respectively connected to a flow controller (12) and a flow control device.
4. A hydrate evaluation experimental system according to claim 3, characterized in that, the air inlet of the gas booster pump is connected to a low-pressure storage tank (26) through a tenth valve (24), and the low-pressure storage tank ( 26) An air compressor (25) is connected.
5. The hydrate evaluation experiment system according to claim 4, characterized in that, the low-pressure storage tank (26) is further connected with a chemical reagent injection device.
6. A hydrate evaluation experimental system according to claim 1, wherein the flow control device comprises a first liquid pool (15), a first piston (18) and a second piston (21), wherein the The liquid outlet of the first liquid pool (15) is respectively connected with the liquid inlet of the first piston (18) and the second piston (21) through the constant pressure pump (16); the first piston (18) and the second piston (21) are respectively connected; The gas outlets of the two pistons (21) are respectively connected to the magnetic stirring vessel (63) through the seventh valve (19) and the ninth valve (22) through the back pressure valve (23).
7. A hydrate evaluation experimental system according to claim 1, characterized in that the chemical reagent injection device comprises a second liquid pool (33), a third piston (36) and a fourth piston (39), wherein the The liquid outlet of the second liquid pool (33) is connected to the liquid inlet of the third piston (36) and the fourth piston (39) through the constant flow pump (34) respectively; the third piston (36) and the fourth piston ( The chemical reagent outlet of 39) is connected to the twentieth valve (42) through the nineteenth valve (41) through the sixteenth valve (37) and the eighteenth valve (40) respectively.
8. A hydrate evaluation experimental system according to claim 1, characterized in that, the experimental system further comprises an exhaust device for evacuation, the exhaust device comprising a twenty-seventh valve (60), the The twenty-seventh valve (60) is arranged on the closed circuit, the outlet of the twenty-seventh valve (60) is respectively connected to the buffer tank (58) and the vacuum pump (57), and the buffer tank (58) is provided with a first Four pressure gauges (59) and twenty-eighth valve (61).
9. A hydrate evaluation experimental system according to claim 1, characterized in that the experimental system further comprises a gas-liquid separation structure, the gas-liquid separation structure comprises a gas-liquid separator (75), and the gas-liquid separator The inlet of (75) is connected to the outlet of the magnetic stirring vessel (63) through the back pressure valve (70) and the twenty-ninth valve (68) in turn; the top gas outlet of the gas-liquid separator (75) is connected to a wet flow meter ( 74); the bottom liquid outlet of the gas-liquid separator (75) is connected to the metering container (77).
10. A kind of hydrate evaluation experimental method is characterized in that, based on a kind of hydrate evaluation experimental system described in any one of claim 1-9, comprises the following steps:

    According to the purpose of the experiment, choose one of the four cases A, B, C, and D to carry out the experiment:

    A: When the synthesis of hydrate is carried out without chemical reagents, among them, the synthesis of combustible ice:

    Stored in the CH ₄ gas or a mixed gas of pressure in (1) a first cylinder through the flow controller (12) into a magnetic stirring vessel (63), the experimental parameters set following the experimental process requirements, Synthesis of combustible ice;

    Synthesis of CO ₂ hydrate:

    _{After pressurizing the CO 2} gas stored in the second gas cylinder (2), it is directly sent into the magnetic stirring vessel (63), and the experimental process parameters are set according to the experimental process requirements, and the synthesis of _{CO 2 hydrate is carried out;}

    B: When chemical reagents are used to synthesize hydrates, among which, combustible ice is synthesized:

    Stored in the CH ₄ gas or a mixed gas of pressure in (1) a first cylinder through the flow controller (12) into the magnetic stirrer (63) of the container; the same time, the use of chemical reagents means of injecting chemical reagents In the magnetic stirring vessel (63), the experimental process parameters are set according to the experimental process requirements, and the synthesis of combustible ice is carried out;

    Synthesis of CO ₂ hydrate:

    Directly stored into the magnetic stirrer (63) in the container pressurized in the CO ₂ gas (2) a second cylinder; the same time, the use of a chemical agent injection Chemicals magnetic stirring the injection means (63) of the container, following the experimental The process requirements are to set the experimental process parameters and carry out the synthesis of _{CO 2 hydrate;}

    C: Test chemical reagents:

    The chemical reagent required for the experiment is injected into the closed loop through the chemical reagent injection device, the flow speed of the liquid is set, and the circulating pump is started to make the chemical reagent flow in the closed loop; the inlet and outlet of the twenty-fourth valve (52) are measured by the differential pressure sensor The pressure difference of the chemical reagent at the place;

    D: Observe the synthesis or decomposition of hydrates

    CO _{2 is} a gas or CH ₄ through twenty-valve (42) into the closed circuit, disposed in a closed loop using the temperature control means is provided experimental temperature, to simulate the CO ₂ gas or CH ₄ during the transport line , due to the formation of hydrate due to cooling or pressurization, and whether there is a hydrate plunger formed in the valve and the narrow and long pipeline when the temperature is increased or pressurized; and to simulate the chemical removal of the hydrate column in the circulation pipeline plug.

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