Method and apparatus for online production of nanobubble fuel

Abstract

This invention discloses a method for online generation of nanobubble fuel, comprising continuously injecting fuel oil into a preparation unit including two or more stages of jet-circulating dissolvers connected in series and a swirling depressurizer. The liquid flow rate gradually increases to create a jetting and negative pressure effect, drawing gas into the jet-circulating dissolvers and dissolving it in contact with the fuel oil. The gas then sequentially passes through subsequent jet-circulating dissolvers connected in series, forming a circulation within the dissolvers, thereby undergoing multiple mixing and dissolution processes with the gas injected in the first stage. The fuel oil containing dissolved and undissolved gases enters the swirling depressurizer of the preparation unit, where the undissolved gas is separated and returned to the intake area of ​​the jet-circulating dissolvers. The nanobubble fuel oil is continuously discharged from the preparation unit. Using the method and apparatus of this invention, the efficiency of converting dissolved gas into nanobubbles can be effectively improved, and the concentration of nanobubbles in the obtained nanobubble fuel can reach 2 × 10⁻⁶. 8 ~5×10 8 per milliliter.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high-end equipment, in particular to a method and device for generating nanobubble fuel online. BACKGROUND

[0002] More and more gas turbines are applied in power generation, ship power and other fields. Adding hydrogen into fuel is an important way to reduce carbon and nitrogen emissions, and is also an important direction of hydrogen energy clean utilization and enhanced combustion.

[0003] The maximum laminar burning 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, which has the problem of "hydrogen flame backflow". Although high-efficiency 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 liquid. The hydrogen nanobubbles added do not cause backfire, and the fuel with nanobubbles has higher thermal conductivity. After high-pressure injection, the spray produced has large specific surface area, large spray cone angle and small penetration distance, thereby effectively improving the mixing uniformity of fuel and gas, improving the thermal efficiency of the engine and reducing pollutant emissions when the fuel is incompletely combusted.

[0005] CN201480053733.X discloses a nanobubble generator for preparing a liquid solution of nanobubbles, which generates nanobubbles by cavitation, fluid shear and release process. However, this method is only for water system, and when used for nanobubble fuel oil preparation, cavitation and fluid shear can easily cause safety accidents and are difficult to apply.

[0006] The concentration of nanobubbles is related to the concentration of dissolved gas, and the method of releasing pressure to obtain nanobubble fuel has attracted widespread attention. CN202010665795.3 discloses a compression type nanometer hydrogen bubble diesel fuel preparation device, method and use, which makes hydrogen and diesel oil reach a predetermined pressure, and then releases the hydrogen / diesel oil solution in the compression cylinder to an oil-gas separator for separation to obtain nanometer hydrogen bubble / diesel oil mixed fuel. CN201910579114.9 discloses a hedge mixing nanometer hydrogen bubble diesel fuel preparation device, method and use, which uses a bellows wall to strengthen hydrogen dissolution and a buffer to prolong the residence time, and finally obtains nanobubble fuel through a pressure release and separation device. CN202111366716.X discloses an engine oxygen-rich micro-nanobubble fuel supply control system and method, which obtains liquid fuel containing nanobubbles through an oxygen-rich micro-nanobubble fuel generation system, an oxygen-rich micro-nanobubble fuel storage device, a pressure limiting valve and an oil-gas separation device. However, the above-mentioned patents all need to set a large-volume oil-gas separator, which cannot produce nanobubble fuel online in a compact engine space. SUMMARY

[0007] The present application aims to overcome the deficiencies of the prior art, and provides a method and device for producing nanobubble fuel online to improve the efficiency of converting dissolved gas into nanobubbles when preparing nanobubble fuel.

[0008] To achieve the above-mentioned purpose, the first aspect of the present application provides a method for producing nanobubble fuel online, comprising the following steps:

[0009] S1: continuously injecting fuel oil into a preparation unit comprising two or more stages of jet loop dissolvers connected in series and a cyclone pressure releaser, in the first stage jet loop dissolver of the preparation unit, gradually increasing the liquid flow rate after entering the tapered inlet of the jet loop dissolver to form jetting and negative pressure effect, absorbing gas into the jet loop dissolver and dissolving with the fuel oil, then sequentially passing through one or more stages of jet loop dissolvers connected in series, and in each stage of jet loop dissolver, forming a loop by the inner cylinder arranged inside the jet loop dissolver, thereby mixing and dissolving with the first stage of injected gas multiple times;

[0010] S2: fuel oil containing dissolved gas and undissolved gas enters the cyclone pressure releaser of the preparation unit, the undissolved gas is separated from the cyclone pressure releaser and returned to the gas absorption area of the jet loop dissolver, and the nanobubble fuel oil is continuously discharged from the preparation unit.

[0011] According to the application, the gas is hydrogen or methane, the gas is dehydrated before being injected into the preparation unit, and has a pressure of 3.1-3.9 MPa; the fuel oil is selected from diesel, kerosene and ethanol, and the pressure of the liquid fuel oil is set to 3-5 MPa.

[0012] According to the application, the residence time of the fuel oil in the jet loop dissolver is 2-10 s, and the number of jet loop dissolvers in series satisfies the liquid residence time.

[0013] According to the preferred embodiment of the application, the residence time of the fuel oil in the jet loop dissolver is set as follows:

[0014] When the temperature of the fuel oil is -10-10 ℃, the residence time is 8-10 s; when the temperature of the fuel oil is 10-30 ℃, the residence time is 5-8 s; and when the temperature of the fuel oil is 30-90 ℃, the residence time is 2-5 s.

[0015] Further, the liquid fuel oil has a jet loop liquid Reynolds number of 3400-34000 and a liquid velocity of 4-40 m / s at the end of the tapered inlet of the jet loop dissolver during the process of contacting and dissolving the liquid fuel oil with the gas.

[0016] Further, the liquid fuel oil containing the soluble gas has a cyclone tangential velocity of 5-20 m / s and a cyclone centrifugal acceleration of 2500-40000 m / s in the cyclone pressure release device, and the liquid has a residence time of 0.08-1 s in the cyclone pressure release device. 2

[0017] In the second aspect of the application, a device for generating nanobubble fuel on line is provided, which comprises a preparation unit, a continuous fuel oil inlet arranged at the front end of the preparation unit, and a continuous nanobubble fuel oil outlet arranged at the rear end of the preparation unit, wherein the preparation unit comprises two or more jet loop dissolvers connected in series, and a cyclone pressure release device connected to the rear end of the last jet loop dissolver, and wherein:

[0018] The front end of the jet loop dissolver is a tapered inlet, and the rear end is a loop outlet, the continuous fuel oil inlet is connected to the tapered inlet of the first jet loop dissolver, the loop outlet of the front jet loop dissolver is connected to the tapered inlet of the rear jet loop dissolver, and each jet loop dissolver is provided with an inner cylinder, the front end and the rear end of the inner cylinder correspond to the tapered inlet and the loop outlet respectively, and the inner cylinder separates the inside of the jet loop dissolver into a front flow area inside the inner cylinder and a return flow area outside the inner cylinder, and the first jet loop dissolver is further provided with a dissolver gas inlet near the tapered inlet.

[0019] ​The main body of the swirling pressure relief device is a swirling fluid cavity. A tangential inlet is provided on the upper side wall of the swirling fluid cavity, and a gas outlet and a nanobubble fuel oil outlet are provided at the top and bottom, respectively. The tangential inlet is connected to the circulation outlet of the last jet circulation dissolver, and the nanobubble fuel oil continuous outlet is connected to the nanobubble fuel oil outlet of the swirling pressure relief device.

[0020] According to the present invention, the diameter of the end channel of the converging inlet of the jet circulation melt is 1 to 5 mm, the diameter of the forward flow region inside the inner cylinder is 1.5 to 3 times the diameter of the end channel of the converging inlet, and the cross-sectional area of ​​the return flow region is 0.8 to 9 times the cross-sectional area of ​​the forward flow region.

[0021] Furthermore, the length of the inner cylinder of the jet-flow dissolver is 10 to 200 times the diameter of the end channel of the converging inlet, and the distance between the right end face of the inner cylinder and the end section of the converging inlet is 2 to 20 times the diameter of the end channel of the converging inlet.

[0022] Furthermore, the diameter of the tangential inlet of the cyclone pressure reliever is 2-8 mm, and the diameter of the cyclone cavity is 3-9 times the diameter of the tangential inlet.

[0023] Furthermore, the distance between the axis of the tangential inlet and the top end face of the cyclone pressure reliever is 2 to 5 times the diameter of the tangential inlet, and the distance between the axis of the tangential inlet and the axis of the liquid outlet of the cyclone pressure reliever is 10 to 50 times the diameter of the tangential inlet.

[0024] The method and apparatus for online generation of nanobubble fuel of the present invention can effectively improve the efficiency of converting dissolved gas into nanobubbles during the preparation of nanobubble fuel. The concentration of nanobubbles in the obtained nanobubble fuel can reach 2 × 10⁻⁶. 8 ~5×10 8 per milliliter. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the apparatus and process for online generation of nanobubble fuel according to the present invention, wherein the multi-stage jet circulation melter is arranged in series.

[0026] Figure 2 for Figure 1 A schematic diagram of a multi-stage jet circulation melter in an online nanobubble fuel generation device, arranged in series. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the described embodiments are merely some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of the present invention.

[0028] Example 1: Apparatus and process for online generation of nanobubble fuel

[0029] like Figure 1 As shown, the online nanobubble fuel generation device of the present invention includes a preparation unit, a fuel oil continuous inlet 3 disposed at the front end of the preparation unit, and a nanobubble fuel oil continuous outlet 4 disposed at the rear end of the preparation unit. The preparation unit includes two or more stages of jet circulation dissolvers 1 connected in series, and a swirling pressure relief device 2 connected to the rear end of the last stage jet circulation dissolver 1.

[0030] Furthermore, the front end of the jet-circulating solvent 1 is a tapered inlet 11, and the rear end is a circulating outlet 12. The fuel oil continuous inlet 3 is connected to the tapered inlet 11 of the first-stage jet-circulating solvent 1, and the circulating outlet 12 of the previous-stage jet-circulating solvent 1 is connected to the tapered inlet 11 of the next-stage jet-circulating solvent 1. Each jet-circulating solvent 1 is provided with an inner cylinder 13. The front end and the rear end of the inner cylinder 13 correspond to the tapered inlet 11 and the circulating outlet 12, respectively, and divide the interior of the jet-circulating solvent 1 into a forward flow region 14 inside the inner cylinder 13 and a return flow region 15 outside the inner cylinder 13. In addition, the first-stage jet-circulating solvent 1 is also provided with a solvent gas inlet 16 near the tapered inlet 11.

[0031] The main body of the swirling pressure relief device 2 is a swirling cavity 21. A tangential inlet 22 is provided on the upper side wall of the swirling cavity 21, and a gas outlet 24 and a nano-bubble fuel oil outlet 23 are provided at the top and bottom, respectively. The tangential inlet 22 is connected to the circulation outlet 12 of the last stage jet circulation dissolver 1, and the nano-bubble fuel oil continuous outlet 4 is connected to the nano-bubble fuel oil outlet 23 of the swirling pressure relief device 2.

[0032] In addition, the gas inlet 16 of the first-stage jet-circulating melter 1 is connected to external gas material through the gas material pipeline 5, and the gas outlet 24 of the cyclone depressurizer 2 is also connected to the melter lifting inlet 16 through the return pipeline 6, which is used to return the gas separated by the cyclone depressurizer 2 to the gas intake area of ​​the jet-circulating melter 1.

[0033] The jet-flow dissolver 1 can enhance the dissolution of gases, and its principle is as follows:

[0034] The fuel oil liquid is injected from the tapered inlet 11 of the jet loop dissolver 1 via the fuel oil continuous inlet 3, and the liquid velocity gradually increases to form jet and negative pressure effect. The negative pressure effect sucks gas from the gas inlet 16 of the jet loop dissolver 1, and the gas-liquid mixture enters the forward flow area 14 inside the inner cylinder 13 under the jet effect. Since the inner cylinder 13 separates the jet loop dissolver 1 into the forward flow area 14 and the return flow area 15, part of the gas-liquid mixture is discharged from the loop outlet 12, and part of the gas-liquid mixture enters the return flow area 15 to form a loop flow. In the jet loop process, the gas-liquid mass transfer area and the liquid phase turbulence are strengthened, and the dissolution speed is greatly improved. At the same time, the return flow area 15 prolongs the liquid residence time, and the liquid at the loop outlet 12 is more likely to reach the saturation state.

[0035] Preferably, the end channel diameter of the tapered inlet 11 of the jet loop dissolver 1 is 1-5 mm, the diameter of the forward flow area 14 inside the inner cylinder 13 is 1.5-3 times the end channel diameter of the tapered inlet 11, and the cross-sectional area of the return flow area 15 is 0.8-9 times the cross-sectional area of the forward flow area 14.

[0036] The length of the inner cylinder 13 of the jet loop dissolver 1 is 10-200 times the end channel diameter of the tapered inlet 11, and the distance between the left side end surface of the inner cylinder 13 (corresponding to the end surface of the tapered inlet 11) and the end cross section of the tapered inlet 11 is 2-20 times the end channel diameter of the tapered inlet 11.

[0037] The cyclone pressure reliever 2 can strengthen the generation of nanobubbles, and the principle is as follows:

[0038] 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, and the centrifugal acceleration can be used to separate micro-bubbles from the liquid efficiently. The cyclone field presents a pressure gradient characteristic of high edge 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 cyclone field does not change with the position, and presents a stable pressure relief effect.

[0039] The cyclone pressure reliever 2 can not only produce a stable pressure relief effect to convert the soluble gas into bubble gas, but also can concentrate micron and millimeter bubbles to the cyclone negative pressure area under the action of centrifugal acceleration and separate them from the top gas outlet 24 quickly, so as to avoid the Ostwald ripening effect of nanobubbles by large bubbles (the process of small bubbles being absorbed by large bubbles), and improve the concentration of nanobubbles remaining in the liquid.

[0040] Preferably, the diameter of the tangential inlet 22 of the cyclone pressure reliever 2 is 2-8 mm, and the diameter of the cyclone cavity 21 is 3-9 times the diameter of the tangential inlet 22.

[0041] The distance between the axis of the tangential inlet 22 and the top end surface of the cyclone pressure release device 2 is 2-5 times the diameter of the tangential inlet 22, and the distance between the axis of the tangential inlet 22 and the axis of the liquid outlet 23 of the cyclone pressure release device 2 is 10-50 times the diameter of the tangential inlet 22.

[0042] As shown in Figure 2 Fig. 4, the second series connection form of the two-stage or more-stage jet loop dissolver 1 in the device for online production of nanobubble fuel of the present application is different from the form shown in Figure 1 Fig. 3, in which the two-stage or more-stage jet loop dissolver 1 is connected in series in front and back, Figure 2 and the form shown in Fig. 5, in which the two-stage or more-stage jet loop dissolver 1 is connected in series in up and down positions. As can be easily understood, the rear end of the lowest-stage jet loop dissolver 1 is connected with a cyclone pressure release device 2, and the fuel oil continuous inlet 3 is connected with the tapered inlet 11 of the first-stage jet loop dissolver 1 arranged in the uppermost layer, and the nanobubble fuel oil continuous outlet 4 is connected with the nanobubble fuel oil outlet 23 of the cyclone pressure release device 2.

[0043] As can be easily understood by those skilled in the art, although the above-mentioned forms of series connection of the multi-stage jet loop dissolver in front and back and in up and down positions are exemplified, based on the actual site conditions, the form of combination of series connection in front and back and in up and down positions or other possible series connection forms can be adopted as needed, which is obvious and belongs to the scope of the present application.

[0044] The method for online production of nanobubble fuel of the present application comprises the following steps:

[0045] S1: continuously injecting fuel oil into a preparation unit comprising two-stage or more-stage jet loop dissolvers 1 connected in series and a cyclone pressure release device 2, in the first-stage jet loop dissolver 1 of the preparation unit, the liquid flow rate is gradually increased after entering the tapered inlet 11 arranged in the jet loop dissolver 1 to form jet and negative pressure effect, the gas is sucked into the jet loop dissolver 1 and dissolved with the fuel oil, and then sequentially passes through one or more-stage jet loop dissolvers 1 connected in series, and in each stage of the jet loop dissolver 1, the internal cylinder 13 arranged inside the jet loop dissolver forms a loop, so that the first-stage injected gas is mixed and dissolved multiple times;

[0046] S2: the fuel oil containing dissolved gas and undissolved gas enters the cyclone pressure release device 2 of the preparation unit, the undissolved gas is separated from the cyclone pressure release device 2 and returned to the gas suction area of the jet loop dissolver 1, and the nanobubble fuel oil is continuously discharged from the preparation unit.

[0047] By using the above-mentioned process of the present application, the liquid phase fuel oil after cyclone pressure release contains nanobubbles with a certain concentration, and the nanobubble concentration reaches 2×10 8~5x10 8 ml.

[0048] According to the application, the gas can be hydrogen or methane, and the gas is dehydrated before being injected into the preparation unit, and has a pressure of 3.1-3.9 MPa.

[0049] Further, the fuel oil can be diesel oil, kerosene, ethanol, or the like, and the residence time of the fuel oil in the jet loop dissolver 1 is 2-10 s; specifically, when the fuel oil temperature is -10-10 ℃, the residence time is 8-10 s; when the fuel oil temperature is 10-30 ℃, the residence time is 5-8 s; and when the fuel oil temperature is 30-90 ℃, the residence time is 2-5 s. The lower the temperature, the slower the molecular diffusion rate of the gas in the fuel oil, and the longer the required circulation time. The number of the jet loop dissolvers 1 in series should meet the liquid residence time.

[0050] Further, the concentration of the nanobubbles in the fuel oil increases with the increase of the pressure of the liquid feed, and preferably, the pressure of the liquid feed is set to 3-5 MPa.

[0051] The parameter capable of reflecting the degree of the jet loop turbulence is the liquid Reynolds number, and the expression of the liquid Reynolds number of the jet loop is wherein D is the diameter of the tapered inlet channel section, u is the liquid velocity at the end of the tapered inlet, ρ is the liquid density, and μ is the liquid viscosity. L L

[0052] In the application, the liquid fuel oil is in contact with the gas in the process of dissolution in the jet loop dissolver 1, and the liquid Reynolds number of the jet loop is preferably 3400-34000, and the liquid velocity at the end of the tapered inlet 11 of the jet loop dissolver 1 is preferably 4-40 m / s.

[0053] In the application, the tangential velocity of the liquid fuel oil containing the dissolved gas in the cyclone pressure release device 2 is preferably 5-20 m / s, the cyclone centrifugal acceleration is preferably 2500-40000 m / s 2 , and the residence time of the liquid in the cyclone pressure release device is preferably 0.08-1 s.

[0054] Example 2

[0055] The embodiment provides an apparatus and a method for generating nanobubble fuel on line, which comprises a preparation unit, a fuel oil continuous inlet 3 arranged at the front end of the preparation unit, and a nanobubble fuel oil continuous outlet 4 arranged at the rear end of the preparation unit, wherein the preparation unit comprises two or more jet loop dissolvers 1 connected in series, and a cyclone pressure release device 2 connected at the rear end of the last jet loop dissolver 1. Details are shown in Example 1, wherein: ​​

[0056] The end channel diameter of the tapered inlet 11 of the jet loop dissolver 1 is 4 mm, the diameter of the forward flow area 14 is 2.5 times the end channel diameter of the tapered inlet 11, and the cross-sectional area of the return flow area 15 is 3 times the cross-sectional area of the forward flow area 14.

[0057] The length of the inner cylinder 13 of the jet loop dissolver 1 is 100 times the end channel diameter of the tapered inlet 11, and the distance between the left end face of the inner cylinder 13 and the end cross section of the tapered inlet 11 is 10 times the end channel diameter of the tapered inlet.

[0058] The diameter of the tangential inlet 22 of the cyclone pressure relief device 2 is 2.5 mm, and the diameter of the cyclone cavity 21 is 8 times the diameter of the tangential inlet 22.

[0059] The distance between the axis of the tangential inlet 22 of the cyclone pressure relief device 2 and the top end face of the cyclone pressure relief device 2 is 4 times the diameter of the tangential inlet 22, and the distance between the axis of the tangential inlet 22 and the axis of the liquid outlet 23 of the cyclone pressure relief device 2 is 30 times the diameter of the tangential inlet 22.

[0060] The flow of the online nanobubble fuel production method of the embodiment includes the following steps:

[0061] S1: continuously inject fuel oil into the preparation unit including a three-stage jet loop dissolver 1 and a cyclone pressure relief device 2, in the first-stage jet loop dissolver 1 of the preparation unit, the liquid flow rate gradually increases after entering the tapered inlet 11 of the jet loop dissolver 1 to form jetting and negative pressure effect, the gas is sucked into the jet loop dissolver 1 and dissolved with the fuel oil, and then sequentially passes through the two-stage jet loop dissolver 1 and mixes and dissolves with the first-stage injected gas;

[0062] S2: the fuel oil containing dissolved gas and undissolved gas enters the cyclone pressure relief device 2 of the preparation unit, the undissolved gas is separated from the cyclone pressure relief device 2 and returned to the gas suction area of the jet loop dissolver 1, and the nanobubble fuel oil is continuously discharged from the preparation unit.

[0063] In the embodiment, the gas is selected as methane, the gas is dehydrated before being injected into the preparation unit, and has a pressure of 6 MPa.

[0064] The liquid is diesel oil, the residence time of the fuel oil in the jet loop dissolver 1 is 3 s, and the temperature of the fuel oil is 33 degrees Celsius.

[0065] The concentration of nanobubbles in the nanobubble fuel oil increases with the increase of the pressure of the liquid feed, and the pressure of the liquid feed is set to 4.5 MPa.

[0066] The liquid fuel oil is in contact with the gas in the jet loop flow dissolver 1, and the liquid Reynolds number of the jet loop flow is 23000, and the liquid velocity at the end of the tapered inlet 11 is 20 m / s.

[0067] The liquid fuel oil containing the dissolved gas is in the cyclone pressure release device 2, and the cyclone tangential velocity is 6.8 m / s, and the cyclone centrifugal acceleration is 4600 m / s 2 , and the residence time of the liquid in the cyclone pressure release device 2 is 0.8 s.

[0068] The length of the single jet loop flow dissolver 1 is 0.8 m, and the known conditions are that the liquid velocity at the end of the tapered inlet 11 is 20 m / s, the diameter of the forward flow area 14 is 2.5 times the diameter of the end channel of the tapered inlet 11, and the cross-sectional area of the return flow area 15 is equal to 3 times the cross-sectional area of the forward flow area. It can be calculated that the residence time of the liquid fuel in the single jet loop flow dissolver 1 is 1 second, and in order to achieve the requirement that the residence time of the fuel oil in the jet loop flow dissolver is 3 s, three jet loop flow dissolvers 1 in series are arranged in this embodiment.

[0069] The three jet loop flow dissolvers in series can be arranged in a straight line (front and back), or can be folded according to the actual space condition (up and down), as shown in Figure 2 .

[0070] The high-concentration nanobubble fuel oil is sampled and analyzed, and the nanobubble concentration is measured by the nanoparticle tracking analysis (NTA) method within one hour of sampling. The instrument model is Malvern NS300.

[0071] The nanobubble diesel fuel is prepared by the method and device of this embodiment, and the nanobubble diesel fuel is obtained, and the measured nanobubble concentration is 3.6×10 8 / mL, as shown in Table 1.

[0072] Embodiment 3

[0073] This embodiment is basically the same as embodiment 2, and the difference is that the number of jet loop flow dissolvers is reduced to 2 based on embodiment 2, and then the same gas-liquid flow experiment is carried out.

[0074] This implementation condition means that the residence time of the fuel oil in the jet loop flow dissolver is reduced from 3 s to 2 s, and the detection result (Table 1) shows that the nanobubble concentration is reduced to 2.1×10 8 / mL, which is lower than the nanobubble concentration of embodiment 2. However, it is still in the range of 2×10 8 ~ 5×10 8 / mL.

[0075] Embodiment 4

[0076] This example is basically the same as example 2, the difference is that on the basis of example 2, the number of jet loop dissolver is reduced to 1, and then the same gas-liquid flow experiment is carried out.

[0077] This implementation condition means that the residence time of fuel oil in the jet loop dissolver is reduced from 3s to 1s, and the test results (Table 1) show that the nano bubble concentration is reduced to 0.9×10 8 / milliliter, lower than the nano bubble concentration of example 2, lower than 2×10 8 / milliliter.

[0078] Example 5

[0079] This example is basically the same as example 2, the difference is that on the basis of example 2, the cyclone pressure relief device is changed to a gas-liquid separation tank with a liquid residence time of 4min, the gas and liquid from the gas-liquid separation tank are mixed together to form a gas-liquid two-phase fuel. Then the same nano bubble concentration test experiment is carried out.

[0080] The test results (Table 1) show that the nano bubble concentration is reduced to 0.5×10 8 / milliliter.

[0081] Reason analysis: because large bubbles cannot be separated quickly, and the pressure reduction rate is suddenly reduced, there is Ostwald ripening effect, the process of large bubbles absorbing small bubbles reduces the nano bubble concentration in the liquid.

[0082] Example 6

[0083] This example is basically the same as example 2, the difference is that on the basis of example 2, the liquid pressure is reduced to 1MPa. The test results (Table 1) show that the nano bubble concentration is reduced to 0.2×10 8 / milliliter.

[0084] Reason analysis: the solubility of saturated gas is reduced, which reduces the total number of molecules converted into nano bubbles.

[0085] Example 7

[0086] This example is basically the same as example 2, the difference is that on the basis of example 2, the pressure of high pressure tank is increased to 6MPa. The test results (Table 1) show that the nano bubble concentration is increased to 4×10 8 / milliliter.

[0087] Reason analysis: increasing the solubility of saturated gas increases the total number of molecules converted into nano bubbles.

[0088] Example 8

[0089] This example is basically the same as example 2, the difference is that on the basis of example 2, the gas injection is cancelled.

[0090] This example is used as a blank sample for testing nano-bubbles by NTA, which proves that the nano-particles measured in examples 2-7, 9-10 are nano-bubbles, not nano-solid particles.

[0091] Example 9

[0092] This example is basically the same as example 2, the difference is that on the basis of example 2, nano-bubble concentration measurement is carried out after 2 days of sampling. The test results are shown in Table 1. It can be seen that after 2 days of placement, the nano-bubble concentration decreases very little, with very good stability.

[0093] Example 10

[0094] This example is basically the same as example 2, the difference is that on the basis of example 2, nano-bubble concentration measurement is carried out after 10 days of sampling. The test results are shown in Table 1. It can be seen that after 10 days of placement, the nano-bubble concentration still decreases very little, with very good stability.

[0095] Example 11

[0096] This example is basically the same as example 2, the difference is that on the basis of example 2, the fuel oil temperature is changed from 33℃ to 2℃, and the test results are shown in Table 1.

[0097] The test results show that the nano-bubble concentration is reduced to 0.65x10 8 The lower the temperature, the slower the molecular diffusion, the slower the dissolution in the jet loop dissolver, and the slower the desorption in the cyclone pressure release, ultimately leading to too low nano-bubble concentration.

[0098] Example 12

[0099] This example is basically the same as example 2, the difference is that on the basis of example 2, the fuel oil temperature is changed from 33℃ to 2℃, and the number of jet loop dissolvers is increased from 3 to 9, and the test results are shown in Table 1.

[0100] The test results show that the nano-bubble concentration is 3.5x10 8 The lower the temperature, the slower the molecular diffusion, the slower the dissolution in the jet loop dissolver, and the slower the desorption in the cyclone pressure release, ultimately leading to too low nano-bubble concentration. The residence time is increased from 3s to 9s, which makes up for the slow diffusion at low temperature.

[0101] Table 1

[0102] Example No. Nanobubble concentration (x 10 8 Individuals per milliliter) 2 3.6 3 2.1 4 0.9 5 0.5 6 0.2 7 4 8 0.04 9 3.2 10 3 11 0.65 12 3.5

[0103] Example 13

[0104] The combustion experiment was performed in a certain gas turbine with a liquid fuel flow rate of 2 L / min, which was the same as the fuel flow rate into the swirl pressure release device in Examples 2-12.

[0105] The combustion experiment was performed using the nano-bubble fuel prepared in Example 2 and the fuel prepared in Example 8, and the results are shown in Table 2.

[0106] Table 2: Combustion experiment data

[0107]

[0108] The results of Table 2 show that the fuel with hydrogen nano-bubbles has a lower NOx emission concentration in the exhaust gas, which is more environmentally friendly.

[0109] Example 14

[0110] The combustion experiment was performed in a certain gas turbine with a liquid fuel flow rate of 2 L / min, which was the same as the fuel flow rate into the swirl pressure release device in Examples 2-12.

[0111] The combustion experiment was performed using the nano-bubble fuel prepared in Example 2 and the gas-liquid two-phase mixed fuel prepared in Example 5, with 0.1 L / min of hydrogen injected into the liquid fuel, and the results are shown in Table 3.

[0112] Table 3: Combustion experiment data

[0113]

[0114] The results of Table 3 show that the fuel with hydrogen nano-bubbles has a lower NOx emission concentration in the exhaust gas, which is more environmentally friendly.

[0115] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for generating nanobubble fuel online, characterized in that, Includes the following steps: S1: A preparation unit for continuous fuel oil injection includes two or more stages of jet-circulating dissolvers connected in series and a vortex depressurizer. In the first stage of the jet-circulating dissolver, the liquid flow rate gradually increases after entering the jet-circulating dissolver by means of the gradually narrowing inlet, forming a jetting and negative pressure effect, which draws the gas into the jet-circulating dissolver and dissolves it in contact with the fuel oil. Then, it passes through one or more subsequent stages of jet-circulating dissolvers connected in series in sequence. In each stage of the jet-circulating dissolver, a circulation is formed by means of the inner cylinder inside the jet-circulating dissolver, thereby mixing and dissolving the gas injected in the first stage multiple times. S2: Fuel oil containing dissolved and undissolved gases enters the swirling pressure relief device of the preparation unit. Undissolved gases are separated from the swirling pressure relief device and returned to the intake area of ​​the jet circulation dissolver, while nanobubble fuel oil is continuously discharged from the preparation unit. The gas is hydrogen or methane, which is dehydrated before being injected into the preparation unit and has a pressure of 3.1 to 3.9 MPa or higher; the fuel oil is selected from diesel, kerosene and ethanol, and the pressure of the incoming liquid fuel oil is set to 3 to 5 MPa.

2. The method according to claim 1, characterized in that, The residence time of fuel oil in the injection circulation solvent is 2 to 10 seconds, and the number of injection circulation solvents connected in series meets the liquid residence time requirement.

3. The method according to claim 2, characterized in that, The residence time of fuel oil in the injection circulation solvent is set as follows: When the fuel oil temperature is -10 to 10°C, the residence time is 8 to 10 seconds; When the fuel oil temperature is 10-30℃, the residence time is 5-8 seconds; When the fuel oil temperature is 30-90℃, the residence time is 2-5 seconds.

4. The method according to claim 1, characterized in that, During the dissolution process of liquid fuel oil in the jet-circulating dissolver, the liquid Reynolds number of the jet-circulating flow is 3400 to 34000, and the liquid velocity at the converging inlet end of the jet-circulating dissolver is 4 to 40 m / s.

5. The method according to claim 1, characterized in that, Inside the cyclone depressurizer, the tangential velocity of the liquid fuel oil containing dissolved gases is 5–20 m / s, and the centrifugal acceleration is 2500–40000 m / s. 2 The residence time of the liquid in the cyclone pressure relief device is 0.08 to 1 second.

6. A device for online generation of nanobubble fuel, characterized in that, The device includes a preparation unit, a continuous fuel oil inlet (3) at the front end of the preparation unit, and a continuous nanobubble fuel oil outlet (4) at the rear end of the preparation unit. The preparation unit includes two or more stages of jet-circulating dissolvers (1) connected in series, and a swirling pressure relief device (2) connected to the rear end of the last stage jet-circulating dissolver (1). The front end of the jet-circulating melter (1) is a tapered inlet (11), and the rear end is a circulating outlet (12). The fuel oil continuous inlet (3) is connected to the tapered inlet (11) of the first-stage jet-circulating melter (1). The circulating outlet (12) of the previous-stage jet-circulating melter (1) is connected to the tapered inlet (11) of the next-stage jet-circulating melter (1). Each jet-circulating melter (1) is provided with an inner cylinder (13). The front end and the rear end of the inner cylinder (13) correspond to the tapered inlet (11) and the circulating outlet (12) respectively, and divide the interior of the jet-circulating melter (1) into a forward flow area (14) inside the inner cylinder (13) and a return flow area (15) outside the inner cylinder (13). Furthermore, the first-stage jet-circulating melter (1) is also provided with a melter gas inlet (16) near the tapered inlet (11). The main body of the swirling pressure relief device (2) is a swirling fluid cavity (21). A tangential inlet (22) is provided on the upper side wall of the swirling fluid cavity (21), and a gas outlet (24) and a nano-bubble fuel oil outlet (23) are provided at the top and bottom, respectively. The tangential inlet (22) is connected to the circulation outlet (12) of the last jet circulation dissolver (1), and the nano-bubble fuel oil continuous outlet (4) is connected to the nano-bubble fuel oil outlet (23) of the swirling pressure relief device (2).

7. The apparatus according to claim 6, characterized in that, The diameter of the end channel of the tapered inlet (11) of the jet flow melt (1) is 1 to 5 mm, the diameter of the forward flow region (14) inside the inner cylinder (13) is 1.5 to 3 times the diameter of the end channel of the tapered inlet (11), and the cross-sectional area of ​​the return flow region (15) is 0.8 to 9 times the cross-sectional area of ​​the forward flow region (14).

8. The apparatus according to claim 6, characterized in that, The length of the inner cylinder (13) of the jet flow dissolver (1) is 10 to 200 times the diameter of the end channel of the converging inlet (11), and the distance between the right end face of the inner cylinder (13) and the end section of the converging inlet (11) is 2 to 20 times the diameter of the end channel of the converging inlet (11).

9. The apparatus according to claim 6, characterized in that, The diameter of the tangential inlet (22) of the swirling pressure reliever (2) is 2 to 8 mm, and the diameter of the swirling cavity (21) is 3 to 9 times the diameter of the tangential inlet (22).

10. The apparatus according to claim 6, characterized in that, The distance between the axis of the tangential inlet (22) and the top end face of the cyclone depressurizer (2) is 2 to 5 times the diameter of the tangential inlet (22), and the distance between the axis of the tangential inlet (22) and the axis of the nanobubble fuel oil outlet (23) of the cyclone depressurizer (2) is 10 to 50 times the diameter of the tangential inlet (22).

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