Low-gas-volume methane / VOCs (Volatile Organic Compounds) recovery device and method based on hydrate technology

Abstract

The invention discloses a low-gas-volume methane / VOCs recovery device and method based on a hydrate technology, the low-gas-volume methane / VOCs recovery device based on the hydrate technology comprises a recovery system, a gas supply system, a synthesis preparation system, a temperature control system and a water supply system; the recovery system is connected with the gas supply system through a pipeline; the gas supply system is connected with the synthesis preparation system through a pipeline; the synthesis preparation system is respectively connected with the temperature control system and the water supply system through pipelines; the recovery system comprises a gas recovery interface and an exhaust fan; the gas recovery interface is connected with the exhaust fan through a pipeline; and the air exhaust fan is connected with the air supply system through a pipeline. The gas temporary storage tank is arranged, multi-point collaborative collection and pressure stabilization can be achieved, low-gas-volume gas is firstly collected into the temporary storage tank, and the synthesis preparation system is not started; the synthesis preparation system is started through pressure control of the tank body, meanwhile, the flow of the booster pump is adjusted by collecting gas data, and pressure balance and continuous gas supply are achieved.

Description

Technical Field

[0001] This invention belongs to the field of hydrate technology, and specifically relates to a low-volume methane / VOCs recovery device and method based on hydrate technology. Background Technology

[0002] During oil and gas field production, a large amount of natural gas is generated through venting, combustion, or leakage. For organized emission sources such as heating furnaces, thermal oil furnaces, and venting combustion, natural gas is mostly recovered and utilized through technologies such as CNG (compressed natural gas) recovery, LNG (liquefied natural gas) liquefaction units, natural gas processing and pressurization units, and natural gas reinjection. However, fugitive emissions such as those caused by equipment maintenance, intermittent venting from the breather valves of dome tanks, and leaks from components that require the end of the production process for repair are usually not recovered. As the proportion of low-volume gas sources in the total methane / VOCs emissions from oil and gas development continues to rise, the recovery of these fugitive natural gas emissions has become a key link in achieving medium- and long-term methane emission intensity and VOCs (volatile organic compounds) emission reduction targets.

[0003] Natural gas hydrate is a white, ice-like solid. Because it releases flammable natural gas upon decomposition, it is also known as "combustible ice." Under standard conditions (temperature 0℃, pressure 1.01325MPa), 1m³ 3 The decomposition of solid natural gas hydrates can produce 164m 3 Natural gas and 0.8m 3 Water has a huge energy density and volume compressibility. Based on this property, application technologies such as gas storage using hydrates have been developed.

[0004] Currently, there is no technology in the chemical and energy sectors for collecting and storing low-emission methane and VOCs escaping gases to prepare natural gas hydrates. Natural gas hydrate preparation technology mainly relies on direct contact between gas and water under high pressure and low temperature conditions. By controlling pressure, temperature, and other conditions, stable hydrate crystals are formed from gas molecules in an aqueous solution. Several technologies have been developed for the synthesis of natural gas hydrates. However, existing technologies face problems such as slow growth rates, low gas storage capacity, imperfect preparation processes, low binding rates between gas and water molecules, and long induction times for hydrate formation, which restrict the development of hydrate synthesis technology. Summary of the Invention

[0005] To address the aforementioned problems, this invention discloses a low-volume methane / VOCs recovery device based on hydrate technology, comprising: a recovery system, a gas supply system, a synthesis and preparation system, a temperature control system, and a water supply system;

[0006] The recovery system is connected to the gas supply system via pipelines;

[0007] The gas supply system is connected to the synthesis preparation system via pipelines;

[0008] The synthesis and preparation system is connected to the temperature control system and the water supply system via pipelines.

[0009] The recovery system includes a gas recovery interface and an exhaust fan;

[0010] The gas recovery interface and the exhaust fan are connected by a pipeline;

[0011] The exhaust fan is connected to the air supply system via pipeline.

[0012] Furthermore, the recovery system also includes electric valves and gas flow sensors;

[0013] The exhaust fan, electric valve, and gas flow sensor are connected in sequence via pipelines;

[0014] The gas flow sensor is connected to the gas supply system via a pipeline.

[0015] Furthermore, the gas supply system includes a temporary storage tank, a first temperature sensor, a first pressure sensor, a safety valve, a first filter, and a gas dryer;

[0016] The first temperature sensor, the first pressure sensor, and the safety valve are located at the top of the temporary storage tank;

[0017] The temporary storage tank outlet, the first filter, and the gas dryer are connected in sequence via pipelines;

[0018] The temporary storage tank is equipped with a gas distributor.

[0019] Furthermore, it also includes a pressurization system and a data acquisition system;

[0020] The booster system includes a booster pump, a buffer, a pressure regulating valve, a second pressure sensor, and a flow sensor connected in sequence via pipelines.

[0021] One end of the booster pump is connected to the gas dryer via a pipeline;

[0022] The flow sensor is connected to the synthesis preparation system via a pipeline;

[0023] The data acquisition system includes a computer;

[0024] The computer is connected to the recovery system, gas supply system, pressurization system, synthesis preparation system, temperature control system, and water supply system, respectively.

[0025] Furthermore, the synthesis preparation system includes a reaction vessel, a standby reaction vessel, an atomizer, a micro-airflow self-rotating aeration mixer, a viewing window, an infrared camera system, a third pressure sensor, a second temperature sensor, and a liquid level sensor;

[0026] The reactor and the standby reactor are connected in parallel.

[0027] The reactor and the backup reactor are equipped with atomizers at the top and micro-airflow self-rotating aeration mixers at the bottom.

[0028] The reactor and the backup reactor are equipped with an infrared camera system, a viewing window, a second temperature sensor and a liquid level sensor on the outer wall, and a third pressure sensor on the top.

[0029] Furthermore, the micro-airflow self-rotating aeration mixer is generally in the shape of a disc-shaped stepped structure;

[0030] The micro-airflow self-rotating aeration mixer is provided with several air holes and several impellers, and a vibration element is provided inside; the air holes are self-closing hole structures.

[0031] The impeller is fixedly installed on the micro-airflow self-rotating aeration mixer and is located above the air holes.

[0032] Furthermore, the longitudinal height of the micro-airflow self-rotating aeration mixer is 200-300 mm, and its diameter is 80-90% of the diameter of the reactor.

[0033] Furthermore, the temperature control system includes a water bath thermostat, a circulating pump, an insulation jacket, a third temperature sensor, and a liquid flow sensor;

[0034] The outlet of the water bath thermostat, the circulation pump, and the inlet of the insulation jacket are connected by pipelines.

[0035] The third temperature sensor and the liquid flow sensor are installed on the pipeline between the circulating pump and the insulation jacket;

[0036] The outlet of the insulation jacket is connected to the inlet of the water bath thermostat via a pipeline;

[0037] The insulation sleeve is positioned around the synthesis and preparation system.

[0038] The water bath temperature of the water bath thermostat is 0-10℃.

[0039] Furthermore, the water supply system includes a clean water tank, an outlet pump, an inlet valve, a return valve, a second filter, and a return pump;

[0040] The water tank outlet, water pump, water inlet valve, and atomizer are connected in sequence via pipelines;

[0041] The bottom outlets of the reactor and the standby reactor are respectively connected to the reflux valves via pipelines;

[0042] The reflux valve, the second filter, the reflux pump, and the clean water tank inlet are connected by pipelines.

[0043] This invention also discloses a recovery method for a low-volume methane / VOCs recovery device based on the above-mentioned hydrate technology, comprising the following steps:

[0044] The escaped gas is recovered, and the working data during the recovery and transportation process is recorded and saved. The working data includes: escaped gas flow rate, ambient temperature, methane / VOCs gas concentration and temporary storage tank pressure.

[0045] By analyzing the working data and combining it with the pressure of the gas supply system's temporary storage tank, it is determined whether to start the preparation of natural gas hydrate, and the flow rate of the booster pump is adjusted according to the gas supply pattern to achieve pressure balance and continuous gas supply.

[0046] When the start-up conditions are met, the water supply system is activated to deliver water to the synthesis and preparation system;

[0047] After the water supply is completed, the temperature control system is run to cool down the synthesis preparation system. The temperature can be set according to actual needs.

[0048] After completing the temperature control settings, the pressurization system is activated to pressurize the recovered gas to 3 MPa to 5 MPa before delivering it to the synthesis preparation system;

[0049] Start the atomizer and micro-airflow self-rotating aeration mixer in the synthesis preparation system to increase gas-liquid contact and accelerate the formation of natural gas hydrate;

[0050] After the reaction has been complete for the set time, the initial preparation of natural gas hydrate is verified by activating the visual window and infrared camera monitoring and pressure and temperature detection data in the synthesis preparation system.

[0051] After data verification, an initial hydrate layer is formed on the water surface. The atomizer is turned off, and heat and pressure are maintained to achieve rapid lateral growth of the hydrate layer and overall downward growth.

[0052] After the initial ice layer forms, the micro-airflow self-rotating aeration mixer at the bottom of the reactor enables rapid generation of the reaction, increasing the gas-liquid contact area and shortening the reaction time.

[0053] The growth rate of the hydrate can be observed through a viewing window. After the hydrate synthesis is completed, switch to the standby reactor to continue the preparation of natural gas hydrate.

[0054] The synthesized reactor is directly sealed at low temperature and transported to the pipeline network or storage tank for desorption and release of natural gas. The reactor that has completed the analysis is returned to the plant area for standby, realizing the switching between them and ensuring the continuous operation of the system.

[0055] Compared with the prior art, the embodiments of the present invention have at least the following advantages:

[0056] 1. The present invention sets up a gas storage tank, which can realize multi-point coordinated collection and pressure stabilization. Low gas volume is first collected into the storage tank without starting the synthesis preparation system; the synthesis preparation system is started by controlling the tank pressure, and the flow rate of the booster pump is adjusted by collecting gas data to achieve pressure balance and continuous gas supply.

[0057] 2. In the synthesis preparation system, the natural gas and water are fully mixed and the reaction is accelerated by the micro-airflow self-rotating aeration mixer at the bottom of the reactor and the top atomizing spray. After the initial ice layer is formed, the top spraying is stopped, and the lateral growth characteristics of the hydrate are realized by relying on the micro-airflow self-rotating aeration mixer, thereby realizing the overall downward growth of the hydrate.

[0058] 3. Configure two sets of reaction vessels. After the synthesis is completed in one set, switch directly to the standby reaction vessel. After the synthesized vessel is transported and analyzed, it is used as a standby vessel again. The two sets of reaction vessels serve as backups for each other, so as to achieve uninterrupted continuous operation of the synthesis preparation system.

[0059] 4. The low-volume methane / VOCs recovery of the present invention is based on the principle of hydrate formation, which utilizes the high gas carrying capacity of hydrates to achieve a significant reduction in the size of the device.

[0060] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0061] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0062] Figure 1 A schematic diagram of a low-volume methane / VOCs recovery device based on hydrate technology according to an embodiment of the present invention is shown;

[0063] Figure 2 A top view of a micro-airflow self-rotating aeration mixer according to an embodiment of the present invention is shown;

[0064] Figure 3 A front view of a micro-airflow self-rotating aeration mixer according to an embodiment of the present invention is shown.

[0065] Reference numerals: 11. Gas recovery interface; 12. Exhaust fan; 13. Electric valve; 14. Gas flow sensor;

[0066] 21. Temporary storage tank; 22. First temperature sensor; 23. First pressure sensor; 24. Safety valve; 25. First filter; 26. Gas dryer; 211. Gas distributor;

[0067] 31. Booster pump; 32. Buffer; 33. Pressure regulating valve; 34. Second pressure sensor; 35. Flow sensor;

[0068] 41. Reactor; 42. Backup reactor; 43. Atomizer; 44. Micro-airflow self-rotating aeration mixer; 45. Viewing window; 46. Infrared camera system; 47. Third pressure sensor; 48. Second temperature sensor; 49. Liquid level sensor;

[0069] 51. Water bath thermostat; 52. Circulating pump; 53. Insulation jacket; 54. Third temperature sensor; 55. Liquid flow sensor;

[0070] 61. Clean water tank; 62. Outlet pump; 63. Inlet valve; 64. Return valve; 65. Second filter; 66. Return pump; 67. Water tank inlet;

[0071] 71. Computer. Detailed Implementation

[0072] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0073] The purpose of this invention is to seek efficient gas hydrate preparation processes and enhancement measures, increase the binding rate of gas molecules and water molecules, study the effects of different enhancement measures on the gas hydrate formation process, shorten the induction time of hydrate formation, and improve its formation rate.

[0074] Figure 1 A schematic diagram of a low-volume methane / VOCs recovery device based on hydrate technology according to an embodiment of the present invention is shown. Figure 1As shown, the present invention proposes a low-volume methane / VOCs recovery device based on hydrate technology, comprising: a recovery system, a gas supply system, a synthesis and preparation system, a temperature control system, and a water supply system;

[0075] The recovery system is connected to the gas supply system via pipelines;

[0076] The gas supply system is connected to the synthesis preparation system via pipelines;

[0077] The synthesis and preparation system is connected to the temperature control system and the water supply system via pipelines.

[0078] The recovery system includes a gas recovery interface 11 and an exhaust fan 12;

[0079] The gas recovery interface 11 and the exhaust fan 12 are connected by a pipeline; the gas recovery interface 11 is connected to the natural gas leak point or discharge point.

[0080] The exhaust fan 12 is connected to the air supply system via a pipeline.

[0081] The recovery system is used to temporarily store the gas collected at each leak point and to achieve continuous gas supply through pressure control and regulation.

[0082] The gas supply system is used to supply gas to the synthesis preparation system. The pressure of the supplied gas is regulated by the booster pump 31 and the pressure regulating valve 33 to provide gas that meets the synthesis conditions.

[0083] The synthesis and preparation system completes the synthesis and storage of hydrates through reaction vessel 41;

[0084] The temperature control system is used to control the liquid temperature inside the reactor 41 to meet the synthesis temperature conditions; at the same time, the desorption and utilization of hydrates can also be achieved by adjusting the temperature range.

[0085] The water supply system is used to supply water to the atomizer 43 at the top of the reactor 41, and at the same time, it meets the requirement of water reflux when the liquid level in the reactor 41 is higher than the high liquid level.

[0086] Gas recovery interface 11 is used for gas collection at the leak point. It can be selected from any collection form such as flared mouth, flange tape, collection bag, flat nozzle, etc., depending on the actual location.

[0087] The exhaust fan 12 is used to pressurize the leaked gas and put it into the temporary storage tank 21, so as to achieve negative pressure collection of the leaked gas and prevent it from escaping.

[0088] This invention provides a low-volume methane / VOCs recovery device and method based on hydrate technology. Based on the principles of hydrate formation and decomposition, and utilizing the high gas carrying capacity of hydrates, the device significantly reduces its volume, enabling efficient recovery of fugitive natural gas emissions such as those caused by equipment maintenance, intermittent venting from the breather valve of the dome tank, and leaks from components requiring the end of the production process for repair. The main functions include:

[0089] 1) By collecting the escaped gas through the recovery system, it is possible to centrally collect leaked natural gas from multiple points into the temporary storage tank 21;

[0090] 2) The gas supply system pressurizes the collected escaping gas through the pressurization system and then delivers it to the synthesis preparation system;

[0091] 3) Finally, the synthesis of natural gas hydrate is completed in the synthesis preparation system by using a temperature control system to assist the gas.

[0092] In some embodiments, the recovery system further includes an electric valve 13 and a gas flow sensor 14;

[0093] The exhaust fan 12, electric valve 13 and gas flow sensor 14 are connected in sequence through pipelines;

[0094] The gas flow sensor 14 is connected to the inlet of the temporary storage tank 21 of the gas supply system via a pipeline.

[0095] Electric valve 13 is used to regulate the flow rate of the collected gas;

[0096] Gas flow sensor 14 is used to monitor the flow rate of collected gas and achieve a balance with the gas volume at the outlet of temporary storage tank 21 through data analysis to ensure continuous gas supply.

[0097] In some embodiments, the gas supply system includes a temporary storage tank 21, a first temperature sensor 22, a first pressure sensor 23, a safety valve 24, a first filter 25, and a gas dryer 26;

[0098] The first temperature sensor 22, the first pressure sensor 23, and the safety valve 24 are located on the top of the temporary storage tank 21;

[0099] The top outlet of the temporary storage tank 21, the first filter 25 and the gas dryer 26 are connected in sequence by pipelines;

[0100] The temporary storage tank 21 is equipped with a gas distributor 211, which is connected to the gas flow sensor 14 through a pipeline to ensure that the gas enters the tank evenly.

[0101] Temporary storage tank 21 is used to collect and temporarily store gas, enabling small-volume gas storage without starting the synthesis preparation system. It starts up after reaching a certain pressure, saving energy while ensuring the continuous operation of the synthesis preparation system.

[0102] The first temperature sensor 22 is used to monitor the temperature of the gas collected in the temporary storage tank 21;

[0103] The first pressure sensor 23 is used to monitor the pressure of the gas collected in the temporary storage tank 21 and to determine the start-up time of the synthesis preparation system based on the pressure.

[0104] Safety valve 24 is used to relieve pressure when the tank pressure increases under abnormal operating conditions, ensuring the safety of the tank.

[0105] The first filter 25 filters out particulate matter and other contaminants inhaled during the on-site collection process, reducing impurities generated during the synthesis process;

[0106] Gas dryer 26 is used to dry synthesis gas, reduce the pressurization and transportation of non-energy media such as water vapor in the gas, and avoid energy waste;

[0107] The temporary storage tank 21 can achieve multi-point coordinated collection and pressure stabilization. Low-volume gas is first collected into the temporary storage tank 21 without starting the synthesis preparation system. The synthesis preparation system is started by controlling the first pressure sensor 23 of the tank. At the same time, the flow rate of the booster pump 31 is adjusted by collecting gas data to achieve pressure balance and continuous gas supply.

[0108] In some embodiments, the low-volume methane / VOCs recovery device based on hydrate technology further includes a pressurization system and a collection system;

[0109] The pressurization system includes a booster pump 31, a buffer 32, a pressure regulating valve 33, a second pressure sensor 34, and a flow sensor 35 connected in sequence via pipelines. The booster pump 31 can quickly pressurize the gas, and the pressurized gas enters the buffer 32. The buffer 32 can be configured to adjust the flow rate and pressure of the gas injected into the reactor 41 by the pressure regulating valve 33, avoiding the difficulty of adjusting the gas injection pressure and flow rate when using the booster pump 31 directly.

[0110] One end of the booster pump 31 is connected to the gas dryer 26 via a pipeline;

[0111] The flow sensor 35 is connected to the bottom inlet of the reaction vessel 41 and the backup reaction vessel 42 of the synthesis preparation system (the connection between the flow sensor 35 and the backup reaction vessel 42 is not shown in the figure) through pipelines;

[0112] The data acquisition system includes a computer 71;

[0113] The computer 71 is connected to the recovery system, gas supply system, pressurization system, synthesis preparation system, temperature control system, and water supply system, respectively. The computer 71 is also connected to each sensor and electrical component in each system. Figure 1 (not shown in the image) to enable automated control; the specific connection relationships will not be elaborated further.

[0114] The acquisition system receives analog signals of temperature, pressure, flow rate, and liquid level. These signals are transmitted to the data acquisition module for data processing to obtain digital signals, which are then transmitted to the computer 71 for data display and storage.

[0115] Booster pump 31 is used for rapid pressurization of gas;

[0116] Buffer 32 is used for buffering and temporarily storing pressurized gas;

[0117] Pressure regulating valve 33 is used to regulate the pressure of the gas outlet of buffer 32;

[0118] The second pressure sensor 34 is used for monitoring and feedback of the gas pressure at the inlet of the reactor 41;

[0119] Flow sensor 35 is used for monitoring and feedback of the gas flow rate at the inlet of reactor 41.

[0120] In some embodiments, the synthesis preparation system includes a reaction vessel 41, a standby reaction vessel 42, an atomizer 43, a micro-airflow self-rotating aeration mixer 44, a viewing window 45, an infrared camera system 46, a third pressure sensor 47, a second temperature sensor 48, and a liquid level sensor 49.

[0121] The reactor 41 and the standby reactor 42 are connected in parallel.

[0122] The reactor 41 and the standby reactor 42 are equipped with an atomizer 43 at the top and a micro-airflow self-rotating aeration mixer 44 at the bottom.

[0123] An infrared camera system 46 is installed around the reactor 41 and the standby reactor 42. A viewing window 45, a second temperature sensor 48 and a liquid level sensor 49 are installed on the outer wall, and a third pressure sensor 47 is installed on the top.

[0124] Reactor 41, used for the synthesis of hydrates;

[0125] Backup reactor 42 is used to switch to standby after the synthesis is completed, ensuring the continuous and stable operation of the synthesis.

[0126] Atomizer 43 is used for pressurized water atomization spraying. It contacts the air intake in the opposite direction to increase the contact area and accelerate the reaction speed.

[0127] The micro-airflow self-rotating aeration mixer 44 is used for air intake at the bottom of the reactor 41. At the same time, the high-pressure airflow drives the small impeller to rotate, realizing the dual functions of bubbling and stirring, increasing the gas-liquid contact area, completing the rapid formation reaction of hydrates, and shortening the reaction time.

[0128] Viewing window 45 is used to observe the formation of the initial ice layer;

[0129] The infrared camera system 46, together with the viewing window 45, is used to observe the formation of hydrates inside the reactor 41 after the initial ice layer has formed.

[0130] The third pressure sensor 47 is used to monitor the pressure of the reactor 41 and the feedback signal, and to adjust the inlet pressure synchronously.

[0131] The second temperature sensor 48 is used to monitor the temperature of the reactor 41 and the feedback signal, and to synchronously adjust the temperature control system.

[0132] The liquid level sensor 49 is used to monitor the liquid level of the reactor 41 and provide feedback signals. When the liquid level is high, the reflux valve 64 and reflux pump 66 are activated in an interlocking manner to reflux the liquid and ensure that the liquid level does not exceed the monitored high liquid level.

[0133] The combination of infrared camera system 46 and viewing window 45 inside the reactor 41 improves the field of view inside the reactor, allowing for a clearer observation of the formation of hydrates inside the reactor.

[0134] The reactor 41 is made of corrosion-resistant material, and a nano-sol coating is added to the inner wall of the reactor 41 to effectively prevent the synthesized material from adhering to the inner wall.

[0135] The reactor 41 is vibrated by a vibrator on the outside, which can accelerate the formation of natural gas hydrates.

[0136] The reactor 41 is equipped with an atomizer 43 and a micro-airflow self-rotating aeration mixer 44. The first step of gas-liquid mixing is achieved by introducing air through the atomizer. The unreacted gas is mixed in the second step by achieving reverse gas-liquid contact through the top atomizer 43, ensuring the gas-liquid contact area throughout the reactor.

[0137] After the atomizer 43 completes the initial ice layer formation of the hydrate, it stops operating and completes the lateral growth characteristics of the hydrate through the micro-airflow self-rotating aeration mixer 44, thereby achieving the overall downward trend of the hydrate.

[0138] The blockage at the air vents of the micro-airflow self-rotating aeration mixer 44 is determined by monitoring the values ​​of the second pressure sensor 34 and the flow sensor 35.

[0139] The system is equipped with a reaction vessel 41 and a standby reaction vessel 42. After the synthesis is completed in the reaction vessel 41, it is directly switched to the standby reaction vessel 42. After the synthesis is completed, the reaction vessel 41 is transported and analyzed and then used as a standby again. The system serves as a backup for each other, so as to achieve uninterrupted continuous operation of the synthesis preparation system.

[0140] Although the above description uses one reactor 41 and one standby reactor 42 (one operational, one standby) as an example, the present invention is not limited thereto, and various configurations can be adopted, such as two operational, one standby, or two operational, two standby, etc. Those skilled in the art can consider the reaction principle of the present invention and practical applications, and any solution can achieve the principle of the present invention.

[0141] like Figure 2 and Figure 3 As shown, in some embodiments, the micro-airflow self-rotating aeration mixer 44 is formed by a single tube spiral, and the whole is in the shape of a disc-like stepped structure, with the distance from the center of the micro-airflow self-rotating aeration mixer 44 gradually increasing; that is, the micro-airflow self-rotating aeration mixer 44 is spiral-shaped, and the spiral extends upward in the axial direction of the center of the micro-airflow self-rotating aeration mixer 44 while maintaining a set spacing, which greatly improves the gas-liquid contact area and can also achieve uniform diffusion of bubbles.

[0142] The micro-airflow self-rotating aeration mixer 44 is provided with several air holes and several impellers, and is equipped with a vibration element inside, which can effectively prevent the air holes from being blocked; the air holes are self-closing holes, which prevent liquid backflow when the gas supply is interrupted.

[0143] The impellers are fixedly installed on the micro-airflow self-rotating aeration mixer 44 and located above the air holes. A gas-driven rotating small impeller is added above the air holes of the micro-airflow self-rotating aeration mixer 44. The rotation of the impeller drives the water flow to achieve a stirring function, further increasing the combination rate of gas molecules and water molecules and improving the hydrate formation rate.

[0144] In some embodiments, the longitudinal height of the micro-airflow self-rotating aeration mixer 44 is 200-300mm, which ensures the stirring effect while reaching the maximum reaction range, and the diameter is 80-90% of the diameter of the reaction vessel 41, ensuring the stirring and mixing effect of the entire reaction vessel.

[0145] In some embodiments, the temperature control system includes a water bath thermostat 51, a circulating pump 52, an insulation jacket 53, a third temperature sensor 54, and a liquid flow sensor 55;

[0146] The outlet of the water bath thermostat 51, the circulation pump 52, and the inlet of the insulation jacket 53 are connected by pipelines.

[0147] The third temperature sensor 54 and the liquid flow sensor 55 are installed on the pipeline between the circulating pump 52 and the insulation jacket 53;

[0148] The outlet of the insulation jacket 53 is connected to the inlet of the water bath thermostat 51 via a pipeline.

[0149] The heat insulation sleeve 53 is installed around the reactor 41 and the spare reactor 42 of the synthesis preparation system;

[0150] The water bath temperature of the water bath thermostat 51 is 0-10℃.

[0151] The water bath thermostat 51 is used to regulate the reaction temperature of the reactor 41. The low temperature is used for hydrate synthesis, and the high temperature is used for hydrate desorption.

[0152] Circulation pump 52 is used for water circulation inside the insulation jacket 53 of the reactor 41;

[0153] Insulation jacket 53 is used to maintain the cooling capacity of reactor 41 and prevent the loss of cooling capacity;

[0154] The third temperature sensor 54 is used to monitor the temperature of the circulating water and provide feedback signals, and to synchronously adjust the temperature control system.

[0155] Liquid flow sensor 55 is used to monitor the flow rate of circulating water and the feedback signal, and to synchronously adjust the flow rate of the circulating pump.

[0156] The temperature control system uses a water bath thermostat 51 to maintain the water bath temperature at 0-10℃, and an insulation jacket 53 is installed to reduce the loss of cold energy, thus providing a suitable reaction temperature for the synthesis preparation system.

[0157] In some embodiments, the water supply system includes a clean water tank 61, an outlet pump 62, an inlet valve 63, a return valve 64, a second filter 65, and a return pump 66;

[0158] The bottom outlet of the clean water tank 61, the water pump 62, the water inlet valve 63 and the atomizer 43 are connected in sequence through pipelines; the water inlet 67 of the clean water tank 61 is connected to the water source.

[0159] The bottom outlets of the reactor 41 and the standby reactor 42 are respectively connected to the reflux valve 64 via pipelines;

[0160] The reflux valve 64, the second filter 65, the reflux pump 66, and the inlet of the clean water tank 61 are connected by pipelines.

[0161] The clear water tank 61 is used to store the water used by the atomizer 43 in the reactor 41, and is also used for high-level reflux in the reactor 41.

[0162] Water pump 62 is used for high-pressure water supply to atomizer 43 in reactor 41;

[0163] Water inlet valve 63 is used to adjust the water supply to atomizer 43;

[0164] Reflux valve 64 is used to adjust the reflux water flow rate at high liquid level in reactor 41;

[0165] The second filter 65 is used for filtering the return water from the reactor 41 to prevent clogging of the return pump 66.

[0166] The reflux pump 66 is used to pressurize the return water from the high liquid level of the reactor 41 into the clean water tank 61.

[0167] The liquid in the clear water tank 61 is pressurized by the water pump 62 to achieve high-pressure spraying of the atomizer 43 in the reactor 41, and when the liquid level reaches the high liquid level set by the liquid level sensor 49, it starts to flow back through the reflux valve 64 and the reflux pump 66 to ensure a constant liquid level.

[0168] Based on the aforementioned low-volume methane / VOCs recovery device based on hydrate technology, this embodiment proposes a low-volume methane / VOCs recovery method based on hydrate technology, comprising:

[0169] Step 1: Recover the escaping gas and record and save the working data during the recovery and transportation process. This working data includes: escaping gas flow rate, ambient temperature, methane / VOCs gas concentration, and pressure of temporary storage tank 21.

[0170] Step 2: By analyzing the working data in Step 1 and combining it with the pressure control of the gas supply system temporary storage tank 21, determine whether to start the preparation of natural gas hydrate, and adjust the flow rate of the booster pump 31 according to the gas supply pattern to achieve pressure balance and continuous gas supply.

[0171] Step 3: If the conditions for starting are met in Step 2, run the water supply system to deliver water to the synthesis preparation system;

[0172] Step 4: After completing the water supply in Step 3, run the temperature control system (temperature adjustment range 0-10℃) to cool down the synthesis preparation system. The temperature can be set according to actual needs.

[0173] Step 5: After completing the temperature control settings in Step 4, run the pressurization system to pressurize the recovered gas to 3 MPa to 5 MPa and then deliver it to the synthesis preparation system;

[0174] Step 6: Start the atomizer 43 and the micro-airflow self-rotating aeration mixer 44 in the synthesis preparation system to increase gas-liquid contact and accelerate the formation of natural gas hydrates of a certain shape.

[0175] Step 7: After the reaction has been complete for a certain period of time, the initial preparation of natural gas hydrate can be verified by activating the visual window 45 and the infrared camera system 46 in the synthesis preparation system, along with the pressure and temperature detection data. In the initial stage of the reaction, visible white granular substances appear in the reactor 41. As bubbles are introduced, obvious white flocculent substances are generated around the bubbles. Eventually, white hydrate spheres are formed on the surface of the methane bubbles, floating on the water surface to form an initial ice layer. Newly formed hydrates continuously adhere to the bottom of the already formed hydrates. When the hydrate ice layer reaches a thickness of 300 mm, the initial preparation is considered complete, and the operation of the atomizer 43 is stopped.

[0176] Step 8: After verifying the data in Step 7, an initial hydrate layer is formed on the water surface. The atomizer 43 is turned off, and heat and pressure are maintained to achieve rapid lateral growth of the hydrate layer and overall downward growth.

[0177] Step 9: After the initial ice layer is formed, the micro airflow self-rotating aeration mixer 44 at the bottom of the reactor 41 enables rapid generation reaction, increases the gas-liquid contact area, and shortens the reaction time.

[0178] Step 10: Observe the growth rate of hydrate through the viewing window 45. After the hydrate synthesis is completed, switch to the standby reactor 42 to continue the preparation of natural gas hydrate.

[0179] Step 11: The synthesized reactor 41 is directly sealed at low temperature and transported to the pipeline network or storage tank for desorption and release of natural gas. The desorption reactor 41 is returned to the unit area for standby, realizing the switching between them and ensuring the continuous operation of the system.

[0180] The data acquisition system of this invention directly obtains the flow signal from the gas flow sensor 14 via an RS485 interface, and the temperature sensor signal comes from a 0-5V analog signal output by the temperature sensor. Simultaneously during the data acquisition process, the control module stores all data via a TF card storage module. The stored experimental data includes gas flow rate, temperature, methane / VOCs gas concentration, and pressure in the temporary storage tank 21.

[0181] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-volume methane / VOCs recovery device based on hydrate technology, characterized in that, include: Recovery system, gas supply system, synthesis and preparation system, temperature control system, and water supply system; The recovery system is connected to the gas supply system via pipelines; The gas supply system is connected to the synthesis preparation system via pipelines; The synthesis and preparation system is connected to the temperature control system and the water supply system via pipelines. The recovery system includes a gas recovery interface (11) and an exhaust fan (12); The gas recovery interface (11) and the exhaust fan (12) are connected by a pipeline; The exhaust fan (12) is connected to the air supply system via a pipeline.

2. The low-volume methane / VOCs recovery device based on hydrate technology according to claim 1, characterized in that, The recovery system also includes an electric valve (13) and a gas flow sensor (14); The exhaust fan (12), electric valve (13) and gas flow sensor (14) are connected in sequence through pipelines; The gas flow sensor (14) is connected to the gas supply system via a pipeline.

3. The low-volume methane / VOCs recovery device based on hydrate technology according to claim 1, characterized in that, The gas supply system includes a temporary storage tank (21), a first temperature sensor (22), a first pressure sensor (23), a safety valve (24), a first filter (25), and a gas dryer (26); The first temperature sensor (22), the first pressure sensor (23), and the safety valve (24) are located on the top of the temporary storage tank (21); The outlet of the temporary storage tank (21), the first filter (25), and the gas dryer (26) are connected in sequence by pipelines; The temporary storage tank (21) is equipped with a gas distributor (211).

4. The low-volume methane / VOCs recovery device based on hydrate technology according to claim 3, characterized in that, It also includes a booster system and a data acquisition system; The pressurization system includes a booster pump (31), a buffer (32), a pressure regulating valve (33), a second pressure sensor (34), and a flow sensor (35) connected in sequence via pipelines; One end of the booster pump (31) is connected to the gas dryer (26) via a pipeline; The flow sensor (35) is connected to the synthesis preparation system via a pipeline; The data acquisition system includes a computer (71); The computer (71) is connected to the recovery system, the gas supply system, the pressurization system, the synthesis preparation system, the temperature control system, and the water supply system, respectively.

5. The low-volume methane / VOCs recovery device based on hydrate technology according to claim 1, characterized in that, The synthesis preparation system includes a reaction vessel (41), a standby reaction vessel (42), an atomizer (43), a micro-airflow self-rotating aeration mixer (44), a viewing window (45), an infrared camera system (46), a third pressure sensor (47), a second temperature sensor (48), and a liquid level sensor (49). The reactor (41) and the standby reactor (42) are connected in parallel; The reactor (41) and the standby reactor (42) are equipped with an atomizer (43) at the top and a micro-airflow self-rotating aeration mixer (44) at the bottom. The reactor (41) and the standby reactor (42) are equipped with an infrared camera system (46) around their perimeters, a viewing window (45), a second temperature sensor (48) and a liquid level sensor (49) on their outer walls, and a third pressure sensor (47) on their top.

6. The low-volume methane / VOCs recovery device based on hydrate technology according to claim 5, characterized in that, The micro-airflow self-rotating aeration mixer (44) is generally in the shape of a disc-shaped stepped structure; The micro-airflow self-rotating aeration mixer (44) is provided with several air holes and several impellers, and is equipped with a vibration element inside; the air holes are self-closing hole structures. The impeller is fixedly installed on the micro-airflow self-rotating aeration mixer (44) and located above the air holes.

7. The low-volume methane / VOCs recovery device based on hydrate technology according to claim 5 or 6, characterized in that, The micro-airflow self-rotating aeration mixer (44) has a longitudinal height of 200-300 mm and a diameter of 80-90% of the diameter of the reactor (41).

8. The low-volume methane / VOCs recovery device based on hydrate technology according to claim 1, characterized in that, The temperature control system includes a water bath thermostat (51), a circulating pump (52), an insulation jacket (53), a third temperature sensor (54), and a liquid flow sensor (55); The outlet of the water bath thermostat (51), the circulation pump (52), and the inlet of the insulation jacket (53) are connected by pipelines; The third temperature sensor (54) and the liquid flow sensor (55) are installed on the pipeline between the circulating pump (52) and the insulation jacket (53); The outlet of the insulation sleeve (53) is connected to the inlet of the water bath thermostat (51) via a pipeline; The heat insulation sleeve (53) is set on the periphery of the synthesis preparation system; The water bath temperature of the water bath thermostat (51) is 0-10℃.

9. The low-volume methane / VOCs recovery device based on hydrate technology according to claim 5, characterized in that, The water supply system includes a clean water tank (61), an outlet pump (62), an inlet valve (63), a return valve (64), a second filter (65), and a return pump (66); The outlet of the clean water tank (61), the water pump (62), the water inlet valve (63) and the atomizer (43) are connected in sequence through pipelines; The bottom outlets of the reactor (41) and the standby reactor (42) are respectively connected to the reflux valve (64) through pipelines; The reflux valve (64), the second filter (65), the reflux pump (66), and the inlet of the clean water tank (61) are connected by pipelines.

10. A recovery method based on the low-volume methane / VOCs recovery device based on hydrate technology according to any one of claims 1-9, characterized in that, Includes the following steps: The escaped gas is recovered, and the working data during the recovery and transportation process is recorded and saved. The working data includes: escaped gas flow rate, ambient temperature, methane / VOCs gas concentration and temporary storage tank (21) pressure; By analyzing the working data and combining the pressure of the gas supply system's temporary storage tank (21), it is determined whether to start the preparation of natural gas hydrate, and the flow rate of the booster pump (31) is adjusted according to the gas supply volume pattern to achieve pressure balance and continuous gas supply; When the start-up conditions are met, the water supply system is activated to deliver water to the synthesis and preparation system; After the water supply is completed, the temperature control system is run to cool down the synthesis preparation system. The temperature can be set according to actual needs. After completing the temperature control settings, the pressurization system is activated to pressurize the recovered gas to 3 MPa to 5 MPa before delivering it to the synthesis preparation system; Start the atomizer (43) and micro-airflow self-rotating aeration mixer (44) in the synthesis preparation system to increase gas-liquid contact and accelerate the formation of natural gas hydrate; After the reaction has been complete for the set time, the initial preparation of natural gas hydrate is verified by using the visual window (45) of the synthesis preparation system with infrared camera monitoring and pressure and temperature detection data. After data verification, an initial hydrate layer is formed on the water surface. The atomizer (43) is turned off, and heat preservation and pressure preservation are used to achieve rapid horizontal growth of the hydrate layer and overall downward growth. After the initial ice layer is formed, the micro airflow self-rotating aeration mixer (44) at the bottom of the reactor (41) enables rapid generation reaction, increases gas-liquid contact area, and shortens reaction time. The growth rate of the hydrate can be observed through the viewing window (45). After the hydrate synthesis is completed, switch to the standby reactor (42) to continue the preparation of natural gas hydrate. The synthesized reactor (41) is directly sealed at low temperature and transported to the pipeline or storage tank for desorption and release of natural gas. The reactor (41) after analysis is returned to the unit area for standby, realizing the switching between them and ensuring the continuous operation of the system.

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