阅读说明：本技术 应用微流控芯片产生微气泡并促进水合物生成的实验装置 (Experimental device for generating micro-bubbles and promoting generation of hydrate by applying micro-fluidic chip ) 是由 宋永臣 刘冬蕾 蒋兰兰 刘瑜 杨明军 张毅 赵佳飞 王思佳 于 2020-07-20 设计创作，主要内容包括：应用微流控芯片产生微气泡并促进水合物生成的实验装置,其属于水合物应用领域。该装置主要包括扁平式结构的微流控芯片、芯片连接件,以及为配套的注气系统、注液系统、控温系统等。本发明能够实现利用微流控芯片平台产生微气泡,并利用CCD相机观察和记录微流控芯片中产生的微气泡的过程,以及微气泡在水合物成核和生长过程中的促进作用。相比较震荡法、搅拌法、外加磁场法、添加促进剂法等传统促进水合物生成的方法,微气泡法不仅提高了水合物生成效率,同时也避免了需要另外施加外力或者促进剂影响环境的缺点。(An experimental device for generating micro bubbles and promoting generation of hydrates by applying a micro-fluidic chip belongs to the field of hydrate application. The device mainly comprises a micro-fluidic chip with a flat structure, a chip connecting piece, a gas injection system, a liquid injection system, a temperature control system and the like which are matched. The invention can realize the process of generating micro bubbles by using the micro-fluidic chip platform and observing and recording the micro bubbles generated in the micro-fluidic chip by using the CCD camera and the promotion effect of the micro bubbles in the nucleation and growth process of the hydrate. Compared with traditional methods for promoting the generation of the hydrate, such as a vibration method, a stirring method, an external magnetic field method, an accelerator adding method and the like, the microbubble method not only improves the generation efficiency of the hydrate, but also avoids the defect that the environment is influenced by additional external force or an accelerator.)

1. An experimental device for generating micro bubbles and promoting generation of hydrates by applying a micro-fluidic chip is characterized in that a gas cylinder (1) is connected to a micro-fluidic chip (12) through a gas injection ISCO pump (2) and a gas inlet pipe (1 a), a deionized water cylinder (4) is connected to the micro-fluidic chip (12) through a liquid injection ISCO pump (3) and a liquid inlet pipe (4 a) and a first liquid inlet branch pipe (4 b) and a second liquid inlet branch pipe (4 d) respectively, the micro-fluidic chip (12) is connected to a gas recoverer (8) through a gas outlet pipe (8 a) and a liquid recovery bottle (8 e) through a liquid outlet pipe (8 d) respectively after passing through a gas-liquid outlet pipe (8 a); the method is characterized in that: the micro-fluidic chip (12) is arranged on the closed cooling chamber (7) through a connecting piece (13), and the closed cooling chamber (7) is connected with the cooling circulating pump (9);

the micro-fluidic chip (12) comprises an upper etching sheet (12 a) and a lower carrier (12 b), a first liquid inlet (12 c), a second liquid inlet (12 d), a gas inlet (12 e), a gas-liquid outlet (12 q) and a gas-liquid mixing area (12 m) are arranged on the upper etching sheet (12 a), and the first liquid inlet (12 c) is communicated to the gas-liquid mixing area (12 m) through a gas-liquid micro-flow channel (12 r) after passing through a first liquid filtering structure (12 f) and a first liquid flow channel (12 i); the second liquid inlet (12 d) is communicated to a gas-liquid mixing area (12 m) through a gas-liquid micro-flow channel (12 r) after passing through a second liquid filtering structure (12 h) and a second liquid flow channel (12 k); the gas inlet (12 e) is communicated to a gas-liquid mixing area (12 m) through a gas filtering structure (12 g) and a gas flow channel (12 j) by a gas-liquid micro-flow channel (12 r); the first liquid flow channel (12 i) and the second liquid flow channel (12 k) are symmetrically arranged at two sides of the gas flow channel (12 j); the gas-liquid outlet (12 q) is communicated to the gas-liquid mixing area (12 m) through the outlet filtering structure (12 p) and the outlet flow channel (12 n); the gas-liquid micro-channel (12 r), the gas-liquid mixing area (12 m) and the micro-channel opening between the gas-liquid micro-channel and the gas-liquid mixing area form a flat structure; the connecting piece (13) is connected with the panel (13 a), the backing plate (13 b) and the bottom plate (13 c) through bolt holes (13 i) on two sides by bolts, the microfluidic chip (12) is clamped between the panel (13 a) and the bottom plate (13 c), and the connecting piece (13) clamping the microfluidic chip (12) is arranged in the closed cooling chamber (7); an observation window (13 d) is arranged on the panel (13 a) and the bottom plate (13 c), and a first liquid inlet connecting hole (13 e), an air inlet connecting hole (13 f), a second liquid inlet connecting hole (13 g) and an air-liquid outlet connecting hole (13 h) are also arranged on the panel (13 a); the first liquid inlet branch pipe (4 b) is connected to a first liquid inlet (12 c) through a first liquid inlet branch pipe connector (4 c), the second liquid inlet branch pipe (4 d) is connected to a second liquid inlet (12 d) through a second liquid inlet branch pipe connector (4 e), the gas inlet pipe (1 a) is connected to a gas inlet (12 e) through a gas inlet pipe connector (1 b), and the gas-liquid outlet (12 q) is connected with a gas-liquid outlet pipe (8 a) through an outlet pipe connector (8 b); and a CCD camera (6) is also arranged above the observation window (13 d), and the CCD camera (6) is electrically connected to the data acquisition system (10).

2. The experimental apparatus for generating microbubbles and promoting generation of hydrate by using the microfluidic chip as claimed in claim 1, wherein: the diameter of the gas-liquid micro-flow channel (12 r) is less than 100

3. The experimental apparatus for generating microbubbles and promoting generation of hydrate by using the microfluidic chip as claimed in claim 1, wherein: the micro-bubbles formed through the gas-liquid micro-flow channel (12 r) enter a gas-liquid mixing area (12 m) which promotes the generation of hydrate in the micro-flow chip (12).

Technical Field

The invention belongs to the field of hydrate application, and relates to an experimental device for generating micro bubbles and promoting hydrate generation by using a micro-fluidic chip.

Background

The hydrate is a clathrate compound formed by guest molecules (such as methane, carbon dioxide and the like) and water at low temperature and high pressure. Among them, natural gas hydrate is also called "combustible ice" because its shape is similar to ice and has the characteristic of being combustible. The storage capacity is huge, the energy density is high, one cubic meter of combustible ice can be decomposed into 164 cubic meters of methane, and the combustible ice is regarded as a novel unconventional energy source which is high in combustion heat value, clean and pollution-free. In addition, after decades of research and development, hydrate as a highly concentrated compound has formed a hydrate technology with important industrial application prospect based on hydrate generation and decomposition, which has many-sided significance to human society. For example, the natural gas hydrate can be used for transportation and storage of natural gas, separation, processing and purification of natural gas in industry, and the hydrate formed by other guest molecules can also be used in a plurality of fields such as sewage treatment and seawater desalination, gas mixture separation, hydrate cold storage, near-critical and supercritical extraction of liquid, biological protease extraction, organic aqueous solution concentration, carbon dioxide deep sea storage, nano-scale semiconductor microcrystal synthesis, automobile driving and the like.

However, the formation of hydrates has disadvantages such as long induction time, high formation conditions (low temperature and high pressure), and slow formation rate, and thus, the rapid formation of hydrates is of great importance. The conventional methods for promoting the formation of hydrates include shaking, stirring, external magnetic field, and addition of an accelerator (e.g., THF or SDS), but they have disadvantages such as the necessity of additional external force or the susceptibility to environmental damage. Therefore, a new hydrate formation promoting method is desired to solve the problem of hydrate formation promotion.

Disclosure of Invention

Aiming at the existing problems of the hydrate formation promoting technology, the invention provides a novel hydrate formation promoting method, which utilizes the special structure of a designed microchip to inject gas into a pore channel to generate micro bubbles (bubbles with the diameter of 10-100 mu m), utilizes the characteristics of good stability, large specific surface area, high internal pressure, high interface potential and the like of the micro bubbles compared with common bubbles, and can increase the contact area of a gas-liquid interface and enhance disturbance to ensure that the nucleation condition of the hydrate is mild, thereby promoting the formation of the hydrate.

In order to realize the functions, the technical scheme provided by the invention is an experimental device for generating micro bubbles and promoting the generation of hydrates by applying a microfluidic chip, wherein a gas cylinder is connected to the microfluidic chip by a gas inlet pipe after passing through a gas injection ISCO pump, a deionized water bottle is connected to the microfluidic chip by a first liquid inlet branch pipe and a second liquid inlet branch pipe after passing through a liquid injection ISCO pump and a liquid inlet pipe, and the microfluidic chip is connected to a gas recoverer by a gas outlet pipe and a liquid recovery bottle by a liquid outlet pipe after passing through a gas-liquid outlet pipe; the micro-fluidic chip is arranged on the closed cooling chamber through a connecting piece, and the closed cooling chamber is connected with the cooling circulating pump.

The micro-fluidic chip comprises an upper etching sheet and a lower etching sheet, wherein a first liquid inlet, a second liquid inlet, a gas-liquid outlet and a gas-liquid mixing area are arranged on the upper etching sheet, and the first liquid inlet is communicated to the gas-liquid mixing area through a gas-liquid micro-flow channel after passing through a first liquid filtering structure and a first liquid flow channel; the second liquid inlet is communicated to the gas-liquid mixing area through a gas-liquid microflow channel after passing through the second liquid filtering structure and the second liquid flow channel; the gas inlet is communicated to the gas-liquid mixing area through a gas filtering structure and a gas flow passage; the first liquid flow channel and the second liquid flow channel are symmetrically arranged on two sides of the gas flow channel; the gas-liquid outlet is communicated to the gas-liquid mixing area through the outlet filtering structure and the outlet flow passage; the gas-liquid micro-channel, the gas-liquid mixing area and the micro-channel opening between the gas-liquid micro-channel and the gas-liquid mixing area form a flat structure; the connecting piece is connected with the panel, the base plate and the bottom plate through bolt holes on two sides by bolts, the microfluidic chip is clamped between the panel and the bottom plate, and the connecting piece for clamping the microfluidic chip is arranged in the closed cooling chamber; the panel and the bottom plate are provided with observation windows, and the panel is also provided with a first liquid inlet connecting hole, an air inlet connecting hole, a second liquid inlet connecting hole and a gas-liquid outlet connecting hole; the first liquid inlet branch pipe is connected to the first liquid inlet through a first liquid inlet branch pipe connector, the second liquid inlet branch pipe is connected to the second liquid inlet through a second liquid inlet branch pipe connector, the gas inlet pipe is connected to the gas inlet through a gas inlet pipe connector, and the gas-liquid outlet is connected to the gas-liquid outlet pipe through an outlet pipe connector; and a CCD camera is also arranged above the observation window and is electrically connected to the data acquisition system.

The diameter of the gas-liquid microflow channel is less than 100。

And micro bubbles formed through the gas-liquid micro-flow channel enter a gas-liquid mixing area for promoting the generation of the hydrate in the micro-flow control chip.

The device mainly comprises a micro-fluidic chip, a closed cooling chamber, a gas injection system, a liquid injection system, a temperature control system and a data acquisition system;

the micro-fluidic chip is a high-pressure etching-resistant glass slide with a flat structure, an etching area with sealed bonding periphery is limited in the glass slide, and the etching area comprises a gas flow passage, a liquid flow passage and a gas-liquid mixing area (namely a hydrate generation area). The gas flow channel is a straight flow channel which is provided with a filtering structure at the front end and leads to the gas-liquid mixing area, and the liquid flow channel area is an interconnected square flow channel which is provided with a filtering structure at the front end and symmetrically distributed at the upper side and the lower side of the gas flow channel area. The gas-liquid mixing area is a square etching area behind the gas-liquid flow passage and is connected with one side of the gas-liquid flow passageThe diameter of the opening is less than 100The liquid and the gas can enter the gas-liquid mixing area through the opening, and the other side of the opening is provided with a straight channel with a filtering structure at the rear end for discharging the gas and the liquid. The gas-liquid flow channel, the gas-liquid mixing area and the micro-channel opening between the gas-liquid flow channel and the gas-liquid mixing area form a flat structure, and the structure can enable gas shearing liquid to enter the micro-channel, so that micro-bubbles can be generated and enter the gas-liquid mixing area to promote the formation of hydrate in the area. The chip connecting piece comprises a steel sheet type bottom plate, a steel sheet type panel and four steel sheet type base plates. The bottom plate is provided with four small holes with threads, the four base plates are respectively provided with two small holes, and the upper part of the panel is provided with a square observation window, four large holes with threads and four small holes with threads. The positions of the large holes correspond to the gas inlet, liquid inlet and liquid outlet on the microfluidic chip, and the gas-liquid pipeline injects gas and liquid into the microfluidic chip through the threaded piece and the connecting piece. The small holes on the steel sheet are in one-to-one correspondence and used for fixing the chip.

The gas injection system comprises a gas cylinder, a pressure reducing valve at the outlet of the gas cylinder, a gas injection ISCO pump connected with the gas cylinder through a pipeline, a pipeline leading to a gas injection port of the chip connecting piece from the gas injection ISCO pump, and a threaded piece connected with the connecting piece at the tail end of the pipeline. The liquid injection system comprises a deionized water bottle, a stainless steel reaction kettle, a first liquid inlet branch and a second liquid inlet branch, wherein the deionized water bottle is connected with a liquid injection ISCO pump through a liquid inlet pipe.

The temperature control system comprises a cold bath circulating device, a closed cooling chamber connected with the cold bath circulating device, a heat insulation layer outside the water tank and an ethylene glycol refrigerant. The data acquisition system comprises a CCD camera and corresponding software, and a temperature sensor and a pressure sensor at the air inlet and the air outlet of the microfluidic chip.

Compared with the prior art, the invention has the beneficial effects that: the invention can realize the process of generating the micro-bubbles and promoting the generation of the hydrate by utilizing the micro-fluidic chip platform, observing and recording the micro-bubbles generated in the micro-fluidic chip by utilizing the CCD camera and the promotion effect of the micro-bubbles in the nucleation and growth process of the hydrate. Compared with traditional methods for promoting the generation of the hydrate, such as a vibration method, a stirring method, an external magnetic field method, an accelerator adding method and the like, the microbubble method not only improves the generation efficiency of the hydrate, but also avoids the defect that the environment is influenced by additional external force or an accelerator. The method specifically comprises the following steps: (1) the invention adopts a flat structure to generate micro bubbles, and can utilize the structural characteristics to promote the generation of hydrate in a gas-liquid mixing area by the micro bubbles while stably generating the micro bubbles; (2) according to the invention, the mode that the microchip generates microbubbles is adopted to promote the generation of the hydrate, so that the influence of the addition of the accelerant on the environment is avoided while the hydrate is generated rapidly; (3) the invention reduces the temperature and pressure conditions for generating the hydrate, does not need an external action field and can reduce the energy consumption in the generation process.

Drawings

Fig. 1 is a schematic diagram of an experimental apparatus for generating microbubbles and promoting generation of hydrates by using a microfluidic chip.

Fig. 2 is a structural view of the microfluidic chip.

Fig. 3 is a structural view of the connector.

Fig. 4 is a combination of a connector and a microfluidic chip.

In the figure: 1. the gas cylinder comprises a gas cylinder 1a, a gas inlet pipe 1b, a gas inlet pipe connector 2, a gas injection ISCO pump 3, a liquid injection ISCO pump 4, deionized water 4a, a liquid inlet pipe 4b, a first liquid inlet branch pipe 4c, a first liquid inlet branch pipe connector 4d, a second liquid inlet branch pipe 4e, a second liquid inlet branch pipe connector 5, a pressure reducing valve 6, a CCD camera 7, a closed cooling chamber 8, a gas recoverer 8a, a gas-liquid outlet pipe 8b, a gas-liquid outlet pipe connector 8c, a gas outlet pipe 8d, a liquid outlet pipe 8e, a liquid recovery bottle 9, a cooling circulating pump 10, a data acquisition system 11a, a first needle valve 11b, a second needle valve 11c, a third needle valve 11d, a fourth needle valve 11e, a fifth needle valve 11f, a sixth needle valve 11g, a seventh needle valve 12, a microfluidic chip 12a and an upper etching sheet, 12b, a lower loading plate, 12c, a first liquid inlet, 12d, a second liquid inlet, 12e, a gas inlet, 12f, a first liquid filtering structure, 12g, a gas filtering structure, 12h, a second liquid filtering structure, 12i, a first liquid flow channel, 12j, a gas flow channel, 12k, a second liquid flow channel, 12r, a gas-liquid micro-flow channel, 12m, a gas-liquid mixing area, 12n, an outlet flow channel, 12p, an outlet filtering structure, 12q and a gas-liquid outlet; 13. the liquid inlet device comprises a connecting piece, 13a, a panel, 13b, a backing plate, 13c, a bottom plate, 13d, an observation window, 13e, a first liquid inlet connecting hole, 13f, a gas inlet connecting hole, 13g, a second liquid inlet connecting hole, 13h, a gas-liquid outlet connecting hole, 13i and a bolt hole.

Detailed Description

The following detailed description of the invention refers to the accompanying drawings.

Fig. 1 to 4 show an experimental apparatus for generating microbubbles and promoting generation of hydrates by using a microfluidic chip, in which a methane gas bottle 1 is connected to a microfluidic chip 12 through a gas injection ISCO pump 2 and then a gas inlet pipe 1a, a deionized water bottle 4 is connected to the microfluidic chip 12 through a first liquid inlet branch pipe 4b and a second liquid inlet branch pipe 4d after passing through a liquid injection ISCO pump 3 and a liquid inlet pipe 4a, the microfluidic chip 12 is connected to a gas recovery unit 8 through a gas outlet pipe 8a and then is connected to a liquid recovery bottle 8e through a liquid outlet pipe 8 d; the micro-fluidic chip 12 is arranged on the closed cooling chamber 7 through a connecting piece 13, and the closed cooling chamber 7 is connected with the cooling circulating pump 9;

the micro-fluidic chip 12 comprises an upper etching sheet 12a and a lower etching sheet 12b, wherein the upper etching sheet 12a is provided with a first liquid inlet 12c, a second liquid inlet 12d, a gas inlet 12e, a gas-liquid outlet 12q and a gas-liquid mixing area 12m, and the first liquid inlet 12c is communicated to the gas-liquid mixing area 12m through a gas-liquid micro-flow channel 12r after passing through a first liquid filtering structure 12f and a first liquid flow channel 12 i; the second liquid inlet 12d is communicated to the gas-liquid mixing area 12m through a gas-liquid microflow passage 12r after passing through the second liquid filtering structure 12h and the second liquid flow passage 12 k; the gas inlet 12e is communicated to the gas-liquid mixing area 12m through the gas filtering structure 12g and the gas flow channel 12j via the gas-liquid micro-flow channel 12 r; the first liquid flow path 12i and the second liquid flow path 12k are symmetrically arranged on both sides of the gas flow path 12 j; the gas-liquid outlet 12q is communicated to a gas-liquid mixing zone 12m through an outlet filtering structure 12p and an outlet flow channel 12 n; the connecting piece 13 comprises a panel 13a, a backing plate 13b and a bottom plate 13c, the microfluidic chip 12 is clamped between the panel 13a and the bottom plate 13c, and the connecting piece 13 clamping the microfluidic chip 12 is arranged in the closed cooling chamber 7; an observation window 13d is arranged on the panel 13a and the bottom plate 13c, and a first liquid inlet connecting hole 13e, an air inlet connecting hole 13f, a second liquid inlet connecting hole 13g and an air-liquid outlet connecting hole 13h are also arranged on the panel 13 a; the first liquid inlet branch pipe 4b is connected to a first liquid inlet 12c through a first liquid inlet branch pipe connector 4c, the second liquid inlet branch pipe 4d is connected to a second liquid inlet 12d through a second liquid inlet branch pipe connector 4e, the gas inlet pipe 1a is connected to a gas inlet 12e through a gas inlet pipe connector 1b, and the gas-liquid outlet 12q is connected to a gas-liquid outlet pipe 8a through an outlet pipe connector 8 b; a CCD camera 6 is also arranged above the observation window 13d, and the CCD camera 6 is electrically connected to the data acquisition system 10.

The diameter of the gas-liquid microflow channel 12r is less than 100。

The micro-bubbles formed by the gas-liquid micro-flow channel 12r enter the gas-liquid mixing area 12m of the micro-flow chip 12, and the generation of hydrate is promoted in the area.

When the technical scheme is adopted for working, methane gas is injected into the chip at the flow rate of 1mL/min to generate micro bubbles, methane hydrate is generated when the temperature and pressure conditions reach 7Mpa and 275K, and the experiment of the promotion effect of the micro bubbles on the generation of the hydrate is observed and calculated. The system is connected according to the system diagram of the experimental device shown in figure 1, and the system is tested, and the air leakage position is confirmed.

The fifth needle 11e and the sixth needle valve 11f are opened, and after deionized water is injected into the injection ISCO pump 3 to fill the entire pump volume, the fifth needle 11e and the sixth needle valve 11f are closed. The fourth needle valve is opened, passes through the liquid inlet pipe 4a by the liquid injection ISCO pump 3, and then is divided into two branch pipes; the first liquid inlet branch pipe 4b slowly injects deionized water into a first liquid inlet 12c in the microfluidic chip 12 through a first liquid inlet branch pipe connector 4 c; the second liquid inlet branch pipe 4d slowly injects deionized water into a second liquid inlet 12d of the microfluidic chip 12 through a second branch pipe connector 4e, and the deionized water is simultaneously injected into the two liquid inlets so as to displace residual gas in the microfluidic chip 12 and saturate the chip. Deionized water enters the first liquid inlet 12c, passes through the first liquid filtering structure 12f, the first liquid flow channel 12i and the gas-liquid micro-flow channel 12r, and then enters the gas-liquid mixing area 12 m. Deionized water enters from the second liquid inlet 12d, passes through the second liquid filtering structure 12h and the second liquid flow channel 12k, and then enters the gas-liquid mixing zone 12 m. The fourth needle valve 11d is closed after the liquid flow path and the gas-liquid mixing region 12m are completely saturated with water.

Adding a glycol solution containing about 30% of mass concentration into a water bath in which the closed cooling chamber 7 is placed as a refrigerant, and turning on a cooling circulating pump 9 to reduce the temperature of the whole system to 275K;

and opening the pressure reducing valve 5 and the first needle valve 11a, injecting methane gas from the methane gas bottle 1 to the gas injection ISCO pump 2 until the whole volume of the pump is filled, wherein the initial pressure in the pump is 2MPa, and compressing the methane gas to the preset pressure of 7MPa through the pump after the methane gas is connected with the chip. The first needle valve 11a is closed. The second needle valve 11b and the third needle valve 11c are opened, methane gas passes through the gas inlet pipe 1a at a flow rate of 1mL/min through the gas inlet pipe 12e by the gas injection ISCO pump 2, passes through the gas filtering structure 12g, and is slowly injected into the gas flow passage 12j, the methane gas is compressed in the gas-liquid micro flow passage 12r of the gas flow passage 12j leading to the gas-liquid mixing area 12m, and micro bubbles are generated in the gas-liquid mixing area 12 m.

Keeping the injection flow of the gas injection ISCO pump 2 unchanged, recording and observing the generation condition of micro bubbles in a gas-liquid mixing area 12m in the micro-fluidic chip by using a CCD camera 6, recording the temperature and pressure value of a gas-liquid inlet and outlet of the micro-fluidic chip 12, closing the second needle valve 11b and the third needle valve 11c after hydrate is generated stably in the gas-liquid mixing area 12m, and recording the induction time of the hydrate. And (4) closing the cooling circulating pump 9, opening a seventh needle valve 11g, and decomposing and discharging deionized water and methane gas in the chip.

The above example is one of the specific embodiments of the present invention, and general changes and substitutions by those skilled in the art within the scope of the present invention should be included in the present invention.