Method and device for preparing high-concentration nano bubble fuel

Abstract

The invention discloses a preparation method of high-concentration nano-bubble fuel oil, which adopts a batch preparation mode, fuel oil is supplemented in batches to enter a preparation unit comprising a high-pressure tank, a jet circulation dissolver and a rotational flow pressure relief device, jet is formed by the jet circulation dissolver which forms liquid circulation and gas circulation with the high-pressure tank, and the high-concentration nano-bubble fuel oil is prepared. And the high-concentration nano-bubble fuel oil is prepared in a circulating manner after being contacted and dissolved by sucked gas, and the prepared high-concentration nano-bubble fuel oil is discharged to an oil tank of a gas turbine after being subjected to pressure relief by a rotational flow pressure relief device in batches. The invention further discloses a corresponding preparation device. According to the prepared high-concentration nano-bubble fuel oil, the nano-bubble concentration can reach 1 * 10 < 8 >-1 * 10 < 9 > / ml, the stability is good, and the nano-bubbles can stably exist for several days or even dozens of days.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical machinery, and in particular relates to a method and a device for preparing high-concentration nano bubble fuel. Background Art

[0002] Heavy-duty gas turbines are an important reflection of the country's heavy industry level. When gas turbines are used in strategic areas such as transport power, there is uncertainty about the source of fuel. Flexible fuel gas turbine technology is a major strategic need in my country. Adding hydrogen to the fuel can change the carbon-hydrogen ratio to match the needs of wider loads and flexible fuels.

[0003] The maximum laminar combustion velocity of hydrogen in air is 306 cm / s, while that of methane is 37.6 cm / s. The propagation speed of hydrogen flame is more than 8 times that of natural gas. Traditional hydrogen blending uses gas-liquid dual fuel to enter the combustion chamber, and there is a "hydrogen flame reflux" problem. Although efficient combustion can be achieved, the faster combustion speed leads to unstable combustion and even deflagration thermoacoustic oscillation, affecting safety and stability.

[0004] Nanobubbles can exist stably in liquids, and the added hydrogen nanobubbles will not cause backfire. Moreover, the fuel mixed with nanobubbles has higher thermal conductivity. The spray produced after high-pressure injection has a large specific surface area, a large spray cone angle, and a small penetration distance, thereby effectively improving the mixing uniformity of fuel and gas, improving the thermal efficiency of the engine, and reducing pollutant emissions during incomplete combustion of the fuel.

[0005] The continuous phase of existing nanobubble mixture preparation technology is mostly water, and the dispersed phase is hydrophobic gas such as air and hydrogen. Generally, the stability of microbubbles is improved by adding surfactants to water. This type of technology relies on the strengthening effect of impurities on the bubble surface and charge on interface stability. Fuel oil represented by diesel and fuel represented by hydrogen do not contain hydrophilic polar structures. The traditional nanobubble preparation method based on aqueous surfactant cannot guide the preparation of nanobubble fuel oil. So far, the high-concentration preparation of nanobubbles in non-aqueous, surfactant-free systems (such as fuel oil) still faces huge challenges.

[0006] CN201480053733.X provides a nanobubble generator for preparing a nanobubble liquid solution, which generates nanobubbles by cavitation, fluid shearing and release processes. However, this method is only for water systems. When used for the preparation of nanobubble fuel oil, cavitation and fluid shearing are likely to cause safety accidents and are difficult to apply.

[0007] The concentration of nanobubbles and the concentration of dissolved gases show a certain correlation, and the use of dissolved gas pressure release method to obtain nanobubble fuel has received widespread attention. CN202010665795.3 provides a compressed nano hydrogen bubble diesel mixed fuel preparation device, method and use. After hydrogen and diesel reach a predetermined pressure, the hydrogen / diesel solution in the compression cylinder is released into the oil / gas separator for separation, and then the nano hydrogen bubble / diesel mixed fuel can be obtained. CN201910579114.9 discloses a hedge mixed nano hydrogen bubble diesel mixed fuel preparation device, method and use, which uses a corrugated pipe wall to strengthen hydrogen dissolution and a buffer to extend the residence time, and finally obtains nanobubble fuel by pressure release separation. CN202111366716.X provides a supply control system and method for oxygen-enriched micro-nano bubble fuel for an engine, and obtains liquid fuel containing nanobubbles through an oxygen-enriched micro-nano fuel generation system, an oxygen-enriched micro-nano bubble fuel storage device, a pressure limiting valve, and an oil-gas separation device.

[0008] It is worth noting that nanobubbles can also increase the saturated solubility of gases in liquids. For example, nanobubbles increase the saturated solubility of methane and oxygen in water by 30 times and 2.5 times, respectively (Ghaani, MR, Kusalik, PG and English, NJ (2020) Massive generation of metastable bulk nanobubbles in water by external electric fields. Science Advances 6 (14)). As the number of cycles increases, the concentration of nanobubbles is expected to increase further. The above-mentioned patents all prepare nanobubble fuel oil online, lack the effect of cyclic enrichment, and cannot achieve high-concentration nanobubble preparation. Summary of the invention

[0009] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art, thereby providing a high-concentration nanobubble fuel oil preparation device and process to improve the nanobubble concentration and storage stability in the fuel oil.

[0010] To achieve the above-mentioned purpose, the first aspect of the present invention provides a method for preparing high-concentration nanobubble fuel oil, wherein the method adopts a batch preparation mode, and the fuel oil is added in batches into a preparation unit including a high-pressure tank, a jet circulation dissolver and a cyclone pressure releaser, and a jet is formed by the jet circulation dissolver which forms a liquid circulation and a gas circulation with the high-pressure tank, and the gas is sucked in for contact and dissolution, and the high-concentration nanobubble fuel oil is prepared in a cycle. After the preparation, the high-concentration nanobubble fuel oil is discharged to the fuel tank of the fuel engine after being depressurized in batches by the cyclone pressure releaser.

[0011] Preferably, the preparation process comprises the following steps:

[0012] S1: The fuel oil is first stored in a high-pressure tank, and then high-pressure gas is injected to increase the pressure of the high-pressure tank to 1-5MPa;

[0013] S2: Turn on the booster pump to accelerate the liquid fuel oil in the jet circulation dissolver to form a jet and negative pressure effect, suck in the gas and dissolve it in contact with it, and then return it to the liquid phase area at the bottom of the high-pressure tank through the liquid circulation loop, wherein the undissolved gas rises to the gas phase area at the top of the high-pressure tank, and dissolves in contact with the fuel oil again through the gas circulation loop under the suction effect of the jet circulation dissolver, and the contact dissolution is circulated in this way;

[0014] S3: After 30 to 120 minutes of circulating preparation, the fuel oil containing high-concentration nanobubbles is depressurized by the cyclone pressure relief device and then discharged into the fuel tank of the fuel engine.

[0015] According to a preferred embodiment of the present invention, in step S1, the pressure of the high-pressure tank is controlled at 2-3 MPa.

[0016] According to the present invention, the gas is selected from methane, hydrogen and air, the gas is dehydrated before being injected into the high-pressure tank, and has a pressure of 3.1 to 3.9 MPa; the fuel oil is selected from diesel, kerosene and ethanol.

[0017] Preferably, the cycle time of each batch of fuel oil in the preparation unit is as follows:

[0018] When the fuel oil temperature is -10 to 10°C, the cycle time is 90 to 120 minutes; when the fuel oil temperature is 10 to 30°C, the cycle time is 60 to 90 minutes; when the fuel oil temperature is 30 to 90°C, the cycle time is 30 to 60 minutes.

[0019] According to the present invention, in step S2, excess gas is discharged to the tail gas treatment unit through a safety valve.

[0020] According to a preferred embodiment of the present invention, in step S2, during the dissolution of liquid fuel oil in contact with gas in the jet circulation dissolver, the liquid Reynolds number of the jet circulation is 3400-34000, and the liquid velocity at the tapered inlet end of the jet circulation dissolver is 4-40 m / s.

[0021] According to a preferred embodiment of the present invention, in step S2, inside the cyclone pressure releaser, the tangential velocity of the cyclone of the liquid fuel oil containing dissolved gas is 5 to 20 m / s, and the centrifugal acceleration of the cyclone is 2500 to 40000 m / s. 2 The residence time of the liquid in the cyclone pressure relief device is 0.08 to 1 s.

[0022] According to the present invention, in step S3, large bubbles generated during the pressure release process are separated by a cyclone pressure release device and returned to the gas phase region at the top of the high-pressure tank.

[0023] The second aspect of the present invention provides a high-concentration nano bubble fuel oil preparation device, comprising a high-pressure tank, a jet circulation dissolver and a cyclone pressure releaser, wherein:

[0024] The upper part of the high-pressure tank is a gas phase area, and the lower part is a liquid phase area; the top and bottom of the high-pressure tank are respectively provided with a gas phase outlet and a liquid phase outlet, and the middle part is provided with a fuel oil replenishment inlet; and the upper and lower side walls of the high-pressure tank corresponding to the gas phase area and the liquid phase area are also respectively provided with a return gas inlet and a return fuel oil inlet;

[0025] The jet circulation dissolver has a tapered inlet and a circulation outlet, and is connected to the liquid phase outlet and the return fuel oil inlet of the high-pressure tank through pipelines, respectively, so as to form a liquid circulation loop, and a booster pump is provided on the circulation pipeline at the front end of the tapered inlet; a dissolver gas inlet is also provided on the jet circulation dissolver near the tapered inlet, and the gas phase outlet of the high-pressure tank is connected to the jet dissolver gas inlet through a pipeline, so as to form a gas circulation loop; an inner cylinder is provided inside the jet circulation dissolver, and the front and rear ends of the inner cylinder correspond to the tapered inlet and the circulation outlet, respectively, and the interior of the jet circulation dissolver is divided into a forward flow area inside the inner cylinder and a return flow area outside the inner cylinder;

[0026] The swirl pressure releaser is arranged on the pipeline at the rear end of the booster pump, and its main body is a swirl body cavity. A tangential inlet is arranged on the upper side wall of the swirl body cavity, and a gas outlet and a nano bubble fuel oil outlet are respectively arranged on the top and the bottom.

[0027] According to a preferred embodiment, the channel diameter of the tapered inlet end of the jet circulation dissolver is 1 to 5 mm, the diameter of the forward flow area inside the inner tube is 1.5 to 3 times the channel diameter of the tapered inlet end, and the cross-sectional area of ​​the return flow area is 0.8 to 9 times the cross-sectional area of ​​the forward flow area.

[0028] According to another preferred embodiment, the length of the inner cylinder of the jet circulation dissolver is 10 to 200 times the channel diameter of the tapered inlet end, and the distance between the right end face of the inner cylinder and the cross section of the tapered inlet end is 2 to 20 times the channel diameter of the tapered inlet end.

[0029] According to another preferred embodiment, the diameter of the tangential inlet of the cyclone pressure relief device is 2 to 8 mm, and the diameter D of the cyclone cavity is equal to 3 to 9 times the diameter of the tangential inlet.

[0030] According to another preferred embodiment, the distance L1 between the axis of the tangential inlet and the top end surface of the cyclone pressure relief device is 2 to 5 times the diameter of the tangential inlet, and the distance H between the axis of the tangential inlet and the axis of the liquid outlet of the cyclone pressure relief device is 10 to 50 times the diameter of the tangential inlet.

[0031] According to the present invention, a nanobubble fuel oil discharge valve is provided on the pipeline at the front end of the tangential inlet of the swirl pressure release device, which is used to discharge the prepared high-concentration nanobubble fuel oil in batches; a sampling port is provided on the external pipeline of the nanobubble fuel oil outlet of the swirl pressure release device, which is used to control the quality of the discharged high-concentration nanobubble fuel oil.

[0032] According to the present invention, the gas outlet of the cyclone pressure release device is further connected to the return gas inlet of the high-pressure tank through a pipeline, so as to realize the recycling of the pressure-released and separated gas.

[0033] The present invention has the following beneficial effects:

[0034] 1. The high-concentration nanobubble fuel oil prepared by the present invention has a nanobubble concentration of up to 1×10 8 ~1×10 9 Pieces / mL.

[0035] 2. The high-concentration nanobubble fuel oil prepared by the present invention has nanobubbles that can stably exist for several days or even dozens of days. Therefore, the high-concentration nanobubble fuel oil can be prepared in a ground oil storage unit and added to the fuel tank of the gas engine in batches within a few days after preparation.

[0036] 3. Fuel oil containing high concentrations of nanobubbles has the effect of enhancing combustion and reducing pollution within a few days. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The present invention is a process flow chart of the high-concentration nano bubble fuel oil preparation device.

[0038] Figure 2 for Figure 1 Schematic diagram of the structure of the medium jet circulation dissolver.

[0039] Figure 3 for Figure 1 Schematic diagram of the structure of the medium cyclone pressure relief device.

[0040] Figure 4 The cycle times required to reach the maximum nanobubble concentration at different temperatures (32°C and 22°C) are shown. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present invention are described clearly and completely below in conjunction with the accompanying drawings. It should be understood that the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of the present invention.

[0042] Embodiment 1, high concentration nano bubble fuel oil preparation device and method

[0043] 1.1. High-concentration nano bubble fuel oil preparation device

[0044] like Figure 1 As shown, the high-concentration nano bubble fuel oil preparation device of this embodiment includes a high-pressure tank 1, a jet circulation dissolver 2 and a cyclone pressure releaser 3, wherein:

[0045] The upper part of the high-pressure tank 1 is a gas phase region 11, and the lower part is a liquid phase region 12; the top and bottom of the high-pressure tank 1 are respectively provided with a gas phase outlet 13 and a liquid phase outlet 14, and the middle part is provided with a fuel oil replenishment inlet 15; and the upper and lower side walls of the high-pressure tank 1 corresponding to the gas phase region 11 and the liquid phase region 12 are also respectively provided with a return gas inlet 16 and a return fuel oil inlet 17;

[0046] Combination Figure 2 As shown, the jet circulation dissolver 2 has a tapered inlet 21 and a circulation outlet 22, and is connected to the liquid phase outlet 14 and the return fuel oil inlet 17 of the high-pressure tank 1 through pipelines, thereby forming a liquid circulation loop, and a booster pump 4 is provided on the circulation pipeline at the front end of the tapered inlet 21; a dissolver gas inlet 23 is also provided on the jet circulation dissolver 2 near the tapered inlet 21, and the gas phase outlet 13 of the high-pressure tank 1 is connected to the jet dissolver gas inlet 23 through a pipeline, thereby forming a gas circulation loop; preferably, an inner cylinder 24 is provided inside the jet circulation dissolver 2, and the front and rear ends of the inner cylinder 24 (the right end face and the left end face in the figure) correspond to the tapered inlet 21 and the circulation outlet 22, respectively, and the interior of the jet circulation dissolver 2 is divided into a forward flow area 26 inside the inner cylinder 24 and a return flow area 25 outside the inner cylinder 24;

[0047] Combination Figure 3 As shown, the cyclone pressure releaser 3 is arranged on the pipeline at the rear end of the boost pump 4, and its main body is a cyclone body chamber 31. A tangential inlet 32 ​​is provided on the upper side wall of the cyclone body chamber 31, and a gas outlet 33 and a nano bubble fuel oil outlet 34 are respectively provided on the top and the bottom.

[0048] Combination Figure 2As shown, preferably, the channel diameter at the end of the tapered inlet 21 of the jet circulation dissolver 2 is 1 to 5 mm, the diameter of the forward flow area 26 inside the inner tube 24 is 1.5 to 3 times the channel diameter at the end of the tapered inlet 21, and the cross-sectional area of ​​the return flow area 25 is 0.8 to 9 times the cross-sectional area of ​​the forward flow area 26.

[0049] Preferably, the length of the inner cylinder 24 of the jet circulation dissolver 2 is 10 to 200 times the channel diameter at the end of the tapered inlet 21, and the distance between the right end face of the inner cylinder 24 and the cross-section of the end of the tapered inlet 21 is 2 to 20 times the channel diameter at the end of the tapered inlet 21.

[0050] Combination Figure 3 As shown, the diameter of the tangential inlet 32 ​​of the cyclone pressure release device 3 is 2 to 8 mm, and the diameter D of the cyclone cavity 31 is equal to 3 to 9 times the diameter of the tangential inlet 32 ​​.

[0051] Furthermore, the distance L1 between the axis of the tangential inlet 32 ​​and the top end surface of the cyclone pressure relief device 3 is 2 to 5 times the diameter of the tangential inlet 32 ​​, and the distance H between the axis of the tangential inlet 32 ​​and the axis of the liquid outlet 34 of the cyclone pressure relief device 3 is 10 to 50 times the diameter of the tangential inlet 32 ​​.

[0052] Furthermore, a safety valve 5 is provided on the external pipe of the gas phase outlet 13 at the top of the high-pressure tank 1 for discharging excess gas. A nanobubble fuel oil discharge valve 6 is provided on the pipe at the front end of the tangential inlet 31 of the swirl pressure releaser 3 for discharging the prepared high-concentration nanobubble fuel oil in batches. A sampling port 7 is provided on the external pipe of the nanobubble fuel oil outlet 34 of the swirl pressure releaser 3 for quality control of the discharged high-concentration nanobubble fuel oil. The dissolver gas inlet 23 of the jet circulation dissolver 2 can be connected to different gases according to actual needs, such as methane, hydrogen, air, etc. The gas outlet 33 of the swirl pressure releaser 3 is further connected to the return gas inlet 16 of the high-pressure tank 1 through a pipeline, thereby realizing the reuse of the pressure-released and separated gas.

[0053] In this embodiment, combined with Figure 2 As shown, the working principle of the jet circulation dissolver 2 is as follows:

[0054] The fuel oil liquid is injected from the tapered inlet 21 of the jet circulation dissolver 2, and the liquid speed gradually increases, forming a jet and negative pressure effect; the negative pressure sucks the gas from the gas inlet 23 of the jet circulation dissolver 2, and the gas-liquid mixture enters the forward flow area 26 inside the inner tube 24 under the action of the jet; because the inner tube 24 divides the jet circulation dissolver 2 into the forward flow area 26 and the return flow area 25 inside the inner tube 24, part of the gas-liquid mixture is discharged from the circulation outlet 22, and part enters the return flow area 25 between the outside of the inner tube 24 and the inner wall of the jet circulation dissolver 2, forming a circulation flow. In the process of jet circulation, the gas-liquid mass transfer area and the liquid phase turbulence are enhanced, and the dissolution rate is greatly improved; at the same time, the return flow area 25 prolongs the residence time of the liquid, and the liquid at the circulation outlet 22 is more likely to reach a saturated state, thereby enhancing the dissolution of the gas.

[0055] In this embodiment, combined with Figure 3 As shown, the principle of the cyclone pressure release device 3 to enhance the generation of nanobubbles is as follows:

[0056] The cyclone field has special velocity distribution characteristics and pressure gradient distribution characteristics; the tangential velocity of the cyclone field can form a large centrifugal acceleration, which can be used to efficiently separate micro bubbles from the liquid. The cyclone field presents a pressure gradient characteristic of high wall pressure and low center pressure. The cyclone pressure gradient is usually caused by the tangential velocity, and the pressure gradient is relatively uniform. The decompression rate of the cyclone field does not change with the position, showing a stable decompression effect.

[0057] The cyclone pressure release device 3 can produce a stable pressure release effect, converting the dissolved gas into bubble-state gas, and at the same time, under the action of centrifugal acceleration, concentrate the micron and millimeter bubbles into the central cyclone negative pressure zone 35 and quickly separate them from the gas outlet 33 at the top, thereby avoiding the Ostwald ripening effect (the process of large bubbles absorbing small bubbles) of large bubbles on nanobubbles, thereby increasing the concentration of nanobubbles remaining in the liquid.

[0058] 1.2. Preparation method of high-concentration nano bubble fuel oil

[0059] The high-concentration nano bubble fuel oil preparation method of this embodiment adopts a batch preparation method. The fuel oil is added in batches into a preparation unit including a high-pressure tank, a jet circulation dissolver and a cyclone pressure releaser. The jet is formed by the jet circulation dissolver which forms a liquid circulation and a gas circulation with the high-pressure tank, and the gas is sucked in for contact and dissolution, so as to prepare the high-concentration nano bubble fuel oil in a cycle. After the preparation, the high-concentration nano bubble fuel oil is discharged into the fuel tank of the fuel engine after being depressurized in batches by the cyclone pressure releaser.

[0060] Specifically, the preparation process comprises the following steps:

[0061] S1: The fuel oil is first stored in a high-pressure tank, and then high-pressure gas is injected to increase the pressure of the high-pressure tank to 1-5MPa.

[0062] S2: Turn on the booster pump to accelerate the liquid fuel oil in the jet circulation dissolver to form a jet and negative pressure effect, suck in the gas and dissolve it in contact with it, and then return to the liquid phase area at the bottom of the high-pressure tank through the liquid circulation loop, where the undissolved gas rises to the gas phase area at the top of the high-pressure tank, and dissolves in contact with the fuel oil again through the gas circulation loop under the suction effect of the jet circulation dissolver, and the contact dissolution is circulated in this way. Excess gas is discharged to the tail gas treatment unit through the safety valve.

[0063] S3: After 30 to 120 minutes of circulating preparation, the fuel oil containing high-concentration nanobubbles is depressurized by the cyclone pressure releaser and discharged into the fuel tank of the fuel engine. The large bubbles generated during the depressurization process are separated by the cyclone pressure releaser and returned to the gas phase area at the top of the high-pressure tank.

[0064] In this embodiment, the gas may be methane, hydrogen or air. The gas needs to be dehydrated before being injected into the high-pressure tank of the preparation unit and has a pressure of 3.1 to 3.9 MPa.

[0065] Furthermore, the fuel oil can be diesel, kerosene, ethanol and other fuel oils, and the cycle time of each batch of fuel oil in the preparation unit is 30 to 120 minutes. Specifically, when the fuel oil temperature is -10 to 10°C, the cycle time is 90 to 120 minutes; when the fuel oil temperature is 10 to 30°C, the cycle time is 60 to 90 minutes; when the fuel oil temperature is 30 to 90°C, the cycle time is 30 to 60 minutes. The lower the temperature, the slower the molecular diffusion rate of the gas in the fuel oil, and the longer the required cycle time.

[0066] By adopting the method of the present invention, the concentration of nanobubbles in the fuel oil increases with the pressure of the high-pressure tank, and the pressure of the high-pressure tank comes from the gas pressure, and the pressure of the high-pressure tank is set to 1-5MPa. The higher the pressure of the high-pressure tank, the greater the concentration of nanobubbles, but the greater the energy consumption for preparing nanobubbles, so the optimized pressure of the high-pressure tank is 2-3MPa.

[0067] The parameter that can reflect the turbulence degree of the jet circulation is the liquid Reynolds number. The expression of the liquid Reynolds number of the jet circulation is: Where D is the channel cross-sectional diameter of the converging inlet of the jet circulation dissolver, u is the liquid velocity at the end of the converging inlet, and ρ L is the liquid density, μ L is the viscosity of the liquid.

[0068] Based on the principle of enhanced dissolution in the jet circulation dissolver, in this embodiment, preferably, during the dissolution process of the liquid fuel oil in contact with the gas in the jet circulation dissolver, the liquid Reynolds number of the jet circulation is 3400-34000, and the liquid velocity at the end of the tapered inlet is 4-40 m / s.

[0069] Based on the principle of enhancing the generation of nanobubbles by a cyclone pressure releaser, in this embodiment, the liquid fuel oil containing dissolved gas is inside the cyclone pressure releaser, the cyclone tangential velocity is 5 to 20 m / s, and the cyclone centrifugal acceleration is 2500 to 40000 m / s. 2 The residence time of the liquid in the cyclone pressure relief device is 0.08 to 1 s.

[0070] According to the method of the present invention, during the fuel circulation process of preparing nanobubbles, the nanobubble fuel oil discharge valve is in a closed state. After the preparation is completed, the nanobubble fuel oil discharge valve can be opened to transport the nanobubble fuel oil to the fuel tank of the gas engine under the pressure of the high-pressure tank.

[0071] The method of the present invention can produce nanobubbles with a concentration of 1×10 8 ~1×10 9 Pieces / mL.

[0072] Example 2

[0073] As an application embodiment of the present invention, its process flow is shown in Figure 1 A method for preparing high-concentration nanobubble diesel fuel adopts a batch preparation method, in which fuel oil is added in batches into a preparation unit (the high-concentration nanobubble fuel oil preparation device of Example 1) including a high-pressure tank 1, a jet circulation dissolver 2 and a cyclone pressure releaser 3, and a jet is formed by the jet circulation dissolver 2, and the inhaled gas is contacted and dissolved, and high-concentration nanobubble fuel oil is circulated to prepare the high-concentration nanobubble fuel oil. After the preparation, the high-concentration nanobubble fuel oil is discharged to the fuel tank of the fuel engine in batches after cyclone pressure release.

[0074] Specifically, the preparation method comprises the following steps:

[0075] S1: The fuel oil is first stored in a high-pressure tank, and then high-pressure gas is injected to quickly increase the pressure of the high-pressure tank to 2MPa.

[0076] S2: Turn on the booster pump to accelerate the liquid fuel oil in the jet circulation dissolver to form a jet and negative pressure effect, suck in the gas and dissolve it in contact with it, and then return to the liquid phase area at the bottom of the high-pressure tank, where the undissolved gas rises to the gas phase area at the top of the high-pressure tank, and dissolves in contact with the fuel oil again under the suction effect of the jet circulation dissolver, and the contact dissolution is circulated in this way. Excess gas is discharged to the tail gas treatment unit through the safety valve.

[0077] S3: After the set cycle preparation time, the fuel oil containing high-concentration nanobubbles is depressurized by the cyclone pressure releaser and discharged into the fuel tank of the fuel engine. The large bubbles generated during the depressurization process are separated by the cyclone pressure releaser and returned to the gas phase area at the top of the high-pressure tank.

[0078] In this embodiment, hydrogen is selected as the gas, and the gas is dehydrated before being injected into the preparation unit and has a pressure of 4 MPa.

[0079] The liquid is diesel, the temperature is 32°C, and the circulation time of each batch of fuel oil in the preparation unit is 60 minutes.

[0080] The pressure of the high-pressure tank comes from the gas pressure, and the pressure of the high-pressure tank is set to 2MPa.

[0081] During the contact and dissolution process of the liquid fuel oil with the gas in the jet circulation dissolver 2, the liquid Reynolds number of the jet circulation is 23000, and the liquid velocity at the end of the tapered inlet 21 is 20 m / s.

[0082] The liquid fuel oil containing dissolved gas is inside the swirl pressure releaser 3, the swirl tangential velocity is 6.8m / s, and the swirl centrifugal acceleration is 4600m / s 2 The residence time of the liquid in the cyclone pressure relief device 3 is 0.8s.

[0083] In the preparation unit, the diameter of the end channel of the tapered inlet 21 of the jet circulation dissolver 2 is 4 mm, the diameter of the forward flow area 26 is 2.5 times the diameter of the end channel of the tapered inlet 21, and the cross-sectional area of ​​the return flow area 25 is equal to 3 times the cross-sectional area of ​​the forward flow area 26.

[0084] The length of the inner cylinder 24 of the jet circulation dissolver 2 is 100 times the diameter of the terminal channel of the tapered inlet 21 , and the distance between the right end surface of the inner cylinder 24 and the terminal cross section of the tapered inlet 21 is 10 times the diameter of the terminal channel of the tapered inlet 21 .

[0085] The diameter of the tangential inlet 32 ​​of the swirl pressure release device 3 is 2.5 mm, and the diameter D of the swirl cavity 31 is equal to 8 times the diameter of the tangential inlet 32 ​​.

[0086] The distance L1 between the axis of the tangential inlet 32 ​​of the cyclone pressure relief device 3 and the top end surface of the cyclone pressure relief device 3 is 4 times the diameter of the tangential inlet 32 ​​, and the distance between the axis of the tangential inlet 32 ​​and the axis of the liquid outlet 34 of the cyclone pressure relief device 3 is 30 times the diameter of the tangential inlet 32 ​​.

[0087] During the fuel cycle to prepare nanobubbles, the nanobubble fuel oil discharge valve 6 is in a closed state. After the preparation is completed, the nanobubble fuel oil discharge valve 6 can be opened to transport the nanobubble fuel oil to the fuel tank of the gas engine under the pressure of the high-pressure tank 1.

[0088] The high-concentration nanobubble fuel oil was sampled and analyzed through the sampling port 7. Within one hour of sampling, the nanoparticle tracking analysis (NTA) method was used for measurement. The instrument model was Malvern NS300.

[0089] The measurement results show that the nanobubble diesel prepared by the device and process described in Example 1 can significantly increase the nanobubble concentration, and the nanobubble concentration reaches 7.8×10 8 The specific values ​​are shown in Table 1.

[0090] Example 3

[0091] On the basis of Example 2, the inner cylinder 24 of the jet circulation dissolver 2 was removed, and the tapered inlet 21 of the jet circulation dissolver 2 was changed to a straight pipe inlet, and the liquid velocity of the straight pipe inlet was reduced to 3m / s (less than 4m / s). Then, the experiment with the same gas-liquid flow rate was carried out. The results showed that the nanobubble concentration was reduced to 1.1×10 8 / ml, which is lower than the nanobubble concentration in Example 2.

[0092] Cause analysis: lack of jet circulation to enhance dissolution, slow mass transfer rate, low dissolved gas concentration, resulting in low nanobubble concentration.

[0093] Example 4

[0094] On the basis of Example 2, the cyclone pressure release device 3 was changed to a gas-liquid separation tank with a liquid phase residence time of 4 min, and then the experiment with the same gas-liquid flow rate was carried out. The results showed that the nanobubble concentration was reduced to 0.7×10 8 Pieces / mL.

[0095] Cause analysis: Since large bubbles cannot separate quickly and the pressure reduction rate decreases suddenly, there is an Ostwald ripening effect. The process of large bubbles absorbing small bubbles reduces the concentration of nanobubbles in the liquid.

[0096] Example 5

[0097] On the basis of Example 2, the pressure of the high-pressure tank 1 was reduced to 0.5 MPa. The results showed that the nanobubble concentration was reduced to 0.5×10 8 Pieces / mL.

[0098] Cause analysis: The solubility of saturated gas decreases, resulting in a decrease in the total number of molecules converted into nanobubbles.

[0099] Example 6

[0100] On the basis of Example 2, the pressure of the high-pressure tank 1 was increased to 3 MPa. The results showed that the nanobubble concentration increased to 8.5×108 Pieces / mL.

[0101] Cause analysis: Increasing the solubility of saturated gas increases the total number of molecules converted into nanobubbles. However, because the concentration of nanobubbles is measured at normal pressure and the fuel is also stored at normal pressure, blindly increasing the pressure of the high-pressure tank cannot proportionally increase the concentration of nanobubbles at normal pressure.

[0102] Example 7

[0103] Based on Example 2, after completing the following steps, the gas injection is turned off.

[0104] “Fuel oil is added to the preparation unit in batches, and the nanobubble fuel oil is discharged to the engine tank in batches after preparation. In the preparation unit, the fuel oil is first stored in the high-pressure tank 1, and then the high-pressure gas is injected to quickly increase the pressure of the high-pressure tank 1 to 2MPa, and the booster pump 4 is turned on”. Then the gas injection is turned off, and after the same cycle preparation time of 60 minutes, the nanobubble fuel oil discharge valve 6 is opened, and sampling is carried out through the sampling port 7.

[0105] This comparative example serves as a blank sample for the NTA test of nanobubbles, confirming that the nanoparticles measured in Examples 2-6 and Examples 8-9 are nanobubbles, not nano solid particles.

[0106] Example 8

[0107] Based on Example 2, the nanobubble concentration was measured 2 days after sampling. The results are shown in Table 1.

[0108] Example 9

[0109] On the basis of Example 2, the nanobubble concentration was measured 10 days after sampling. The results are shown in Table 1.

[0110] Example 10

[0111] On the basis of Example 2, diesel was replaced with aviation kerosene, and the nanobubble concentration was measured, and the results are shown in Table 1. The results show that the nanobubble concentration increased slightly, which may be due to the high solubility of hydrogen in kerosene.

[0112] Embodiment 11

[0113] On the basis of Example 2, the diesel was replaced with an ethanol solution with a mass fraction of 80%, and the results are shown in Table 1. The results show that the concentration of nanobubbles is slightly reduced, which may be due to the low solubility of hydrogen in ethanol.

[0114] Example 12

[0115] On the basis of Example 2, hydrogen was replaced by methane, and the test results are shown in Table 1. The results show that the concentration of nanobubbles is slightly reduced, which may be due to the low solubility of methane in diesel.

[0116] Embodiment 13

[0117] On the basis of Example 2, hydrogen was replaced by air, and the test results are shown in Table 1. The results show that the concentration of nanobubbles remains almost unchanged, and the two gas types of hydrogen and air have little effect on the concentration of nanobubbles.

[0118] Table 1: Test results

[0119]

[0120] Embodiment 14

[0121] Based on Example 2, the temperature was changed from 32°C to 22°C, and the cycle time required to reach the maximum nanobubble concentration at different temperatures was tested. The results are as follows: Figure 4 shown.

[0122] Figure 4 The results showed that the time to reach the maximum nanobubble concentration was extended from 6 min to 70 min, the lower temperature resulted in a longer residence time, and the maximum nanobubble concentration remained basically unchanged.

[0123] Embodiment 15

[0124] A combustion experiment was conducted on a gas turbine. The flow rate of the liquid fuel was 2 L / min. The diesel fuels obtained in Example 9 and Example 7 were used respectively. The experimental results are shown in Table 2 below.

[0125] Table 2: Combustion test data

[0126]

[0127] From the results in Table 2, it can be seen that the fuel with hydrogen nanobubbles has a lower NOx emission concentration in the tail gas and is therefore more environmentally friendly.

[0128] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing high-concentration nano bubble fuel oil, characterized in that: The process adopts a batch preparation method, and the fuel oil is added in batches into a preparation unit including a high-pressure tank, a jet circulation dissolver and a cyclone pressure releaser. The jet is formed by the jet circulation dissolver which forms a liquid circulation and a gas circulation with the high-pressure tank, and the gas is sucked in for contact and dissolution, so as to prepare high-concentration nano bubble fuel oil in a cycle. After the preparation, the high-concentration nano bubble fuel oil is released in batches by the cyclone pressure releaser and then discharged to the fuel tank of the fuel engine.

2. The preparation method according to claim 1, characterized in that: The following steps are involved: S1: The fuel oil is first stored in a high-pressure tank, and then high-pressure gas is injected to increase the pressure of the high-pressure tank to 1-5MPa; S2: Turn on the booster pump to accelerate the liquid fuel oil in the jet circulation dissolver to form a jet and negative pressure effect, suck in the gas and dissolve it in contact with it, and then return it to the liquid phase area at the bottom of the high-pressure tank through the liquid circulation loop, wherein the undissolved gas rises to the gas phase area at the top of the high-pressure tank, and dissolves in contact with the fuel oil again through the gas circulation loop under the suction effect of the jet circulation dissolver, and the contact dissolution is circulated in this way; S3: After 30 to 120 minutes of circulating preparation, the fuel oil containing high-concentration nanobubbles is depressurized by the cyclone pressure relief device and then discharged into the fuel tank of the fuel engine.

3. The preparation method according to claim 2, characterized in that: In step S1, the pressure of the high-pressure tank is controlled at 2-3 MPa.

4. The preparation method according to claim 2, characterized in that: The gas is selected from methane, hydrogen and air, and is dehydrated before being injected into the high-pressure tank, and has a pressure of 3.1 to 3.9 MPa; the fuel oil is selected from diesel, kerosene and ethanol.

5. The preparation method according to claim 4, characterized in that: The cycle time of each batch of fuel oil in the preparation unit is as follows: When the fuel oil temperature is -10 to 10°C, the cycle time is 90 to 120 minutes; When the fuel oil temperature is 10-30°C, the cycle time is 60-90 minutes; When the fuel oil temperature is 30-90°C, the cycle time is 30-60 minutes.

6. The preparation method according to claim 2, characterized in that: In step S2, excess gas is discharged to the tail gas treatment unit through a safety valve.

7. The preparation method according to claim 2, characterized in that: In step S2, during the process of liquid fuel oil contacting and dissolving with gas in the jet circulation dissolver, the liquid Reynolds number of the jet circulation is 3400-34000, and the liquid velocity at the end of the tapered inlet of the jet circulation dissolver is 4-40 m / s.

8. The preparation method according to claim 2, characterized in that: In step S2, inside the cyclone pressure releaser, the tangential velocity of the cyclone of the liquid fuel oil containing dissolved gas is 5 to 20 m / s, and the centrifugal acceleration of the cyclone is 2500 to 40000 m / s. 2 The residence time of the liquid in the cyclone pressure relief device is 0.08 to 1 s.

9. The preparation method according to claim 2, characterized in that: In step S3, large bubbles generated during the pressure release process are separated by a cyclone pressure release device and returned to the gas phase region at the top of the high-pressure tank.

10. A high-concentration nano bubble fuel oil preparation device, characterized in that: The invention comprises a high-pressure tank (1), a jet circulation dissolver (2) and a cyclone pressure releaser (3), wherein: The interior of the high-pressure tank (1) has a gas phase region (11) at the top and a liquid phase region (12) at the bottom; the top and bottom of the high-pressure tank (1) are respectively provided with a gas phase outlet (13) and a liquid phase outlet (14), and the middle is provided with a fuel oil replenishment inlet (15); and the side walls of the upper and lower parts of the high-pressure tank (1) corresponding to the gas phase region (11) and the liquid phase region (12) are also respectively provided with a return gas inlet (16) and a return fuel oil inlet (17); The jet circulation dissolver (2) has a tapered inlet (21) and a circulation outlet (22), and is connected to the liquid phase outlet (14) and the return fuel oil inlet (17) of the high-pressure tank (1) through pipelines, respectively, so as to form a liquid circulation loop, and a booster pump (4) is provided on the circulation pipeline at the front end of the tapered inlet (21); a dissolver gas inlet (23) is also provided on the jet circulation dissolver (2) near the tapered inlet (21), and the gas phase outlet (13) of the high-pressure tank (1) is connected to the jet dissolver gas inlet (23) through a pipeline, so as to form a gas circulation loop; an inner cylinder (24) is provided inside the jet circulation dissolver (2), and the front and rear ends of the inner cylinder (24) correspond to the tapered inlet (21) and the circulation outlet (22), respectively, and the interior of the jet circulation dissolver (2) is divided into a forward flow area (26) inside the inner cylinder (24) and a return flow area (25) outside the inner cylinder (24); The cyclone pressure release device (3) is arranged on the pipeline at the rear end of the booster pump (4), and its main body is a cyclone body chamber (31). A tangential inlet (32) is provided on the upper side wall of the cyclone body chamber (31), and a gas outlet (33) and a nano bubble fuel oil outlet (34) are provided at the top and bottom respectively.

11. The preparation device according to claim 10, characterized in that: The diameter of the channel at the end of the tapered inlet (21) of the jet circulation dissolver (2) is 1 to 5 mm, the diameter of the forward flow area (26) inside the inner tube (24) is 1.5 to 3 times the diameter of the channel at the end of the tapered inlet (21), and the cross-sectional area of ​​the return flow area (25) is 0.8 to 9 times the cross-sectional area of ​​the forward flow area (26).

12. The preparation device according to claim 10, characterized in that: The length of the inner cylinder (24) of the jet circulation dissolver (2) is 10 to 200 times the diameter of the channel at the end of the tapered inlet (21), and the distance between the right end surface of the inner cylinder (24) and the cross section at the end of the tapered inlet (21) is 2 to 20 times the diameter of the channel at the end of the tapered inlet (21).

13. The preparation device according to claim 10, characterized in that: The diameter of the tangential inlet (32) of the cyclone pressure release device (3) is 2 to 8 mm, and the diameter D of the cyclone cavity (31) is 3 to 9 times the diameter of the tangential inlet (32).

14. The preparation device according to claim 10, characterized in that: The distance L1 between the axis of the tangential inlet (32) and the top end surface of the cyclone pressure relief device (3) is 2 to 5 times the diameter of the tangential inlet (32), and the distance H between the axis of the tangential inlet (32) and the axis of the liquid outlet (34) of the cyclone pressure relief device (3) is 10 to 50 times the diameter of the tangential inlet (32).

15. The preparation device according to claim 10, characterized in that: A nanobubble fuel oil discharge valve (6) is provided on the pipeline at the front end of the tangential inlet (31) of the swirl pressure release device (3), which is used to discharge the prepared high-concentration nanobubble fuel oil in batches; and a sampling port (7) is provided on the external pipeline of the nanobubble fuel oil outlet (34) of the swirl pressure release device (3), which is used to control the quality of the discharged high-concentration nanobubble fuel oil.

16. The preparation device according to claim 10, characterized in that: The gas outlet (33) of the cyclone pressure release device (3) is further connected to the return gas inlet (16) of the high-pressure tank (1) through a pipeline, thereby realizing the recycling of the pressure-released and separated gas.

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