Method and apparatus for online generation of nanobubble fuel

Abstract

Disclosed in the present invention is a method for online generation of a nanobubble fuel, comprising: continuously injecting a fuel oil into a preparation unit comprising two or more stages of jet loop dissolvers connected in series and a swirling pressure-release device, and gradually increasing the flow rate of a liquid to form jet and negative pressure effects, so that gas is suctioned into a jet loop dissolver and comes into contact with the fuel oil so as to be dissolved, and then the mixture sequentially passes through the subsequent jet loop dissolvers connected in series to form circulating flow in the dissolvers, and is repeatedly mixed and dissolved with gas injected at the first-stage jet loop dissolver; and introducing, into the swirling pressure-release device of the preparation unit, the fuel oil containing dissolved gas and undissolved gas, separating the undissolved gas and returning same to a gas suction region of the jet loop dissolver, and continuously discharging a nanobubble fuel oil from the preparation unit. By using the method and apparatus of the present invention, the efficiency of converting the dissolved gas into nanobubbles can be effectively improved, and the concentration of the nanobubbles in the prepared nanobubble fuel can reach 2×108-5×108 per milliliter.

Description

A method and apparatus for online generation of nanobubble fuel Technical Field

[0001] This invention belongs to the field of high-end equipment technology, specifically, it relates to a method and apparatus for online generation of nanobubble fuel. Background Technology

[0002] With the introduction of the carbon peaking and carbon neutrality strategic goals, net-zero emission gas turbine technology has become a major national need. Gas turbines are increasingly being used in power generation, ship propulsion, and other fields. Incorporating hydrogen into the fuel is an important way to reduce carbon and nitrogen emissions, and also a crucial direction for the clean utilization of hydrogen energy and enhanced combustion.

[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 the hydrogen flame is more than 8 times that of natural gas. Traditional hydrogen blending uses gas and liquid dual fuels to enter the combustion chamber, which has the problem of "hydrogen flame backflow". Although it can achieve efficient combustion, the faster combustion speed leads to unstable combustion or even deflagration and thermoacoustic oscillation, affecting safety and stability.

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

[0005] CN201480053733.X discloses a nanobubble generator for preparing liquid solutions containing nanobubbles, utilizing cavitation, fluid shearing, and release processes to generate nanobubbles. However, this method is only applicable to aqueous systems. When used for the preparation of nanobubble fuel oil, cavitation and fluid shearing can easily lead to safety accidents, making it difficult to apply.

[0006] The concentration of nanobubbles exhibits a certain correlation with the concentration of dissolved gases, and the method of obtaining nanobubble fuel through dissolved gas depressurization has attracted widespread attention. CN202010665795.3 discloses a compression-type nano-hydrogen bubble diesel fuel preparation device, method, and application, which involves bringing hydrogen and diesel to a predetermined pressure, then releasing the hydrogen / diesel solution in the compression cylinder to an oil-gas separator for separation, thereby obtaining nano-hydrogen bubble / diesel fuel. CN201910579114.9 discloses a counter-mixed nano-hydrogen bubble diesel fuel preparation device, method, and application, which uses a corrugated pipe wall to enhance hydrogen dissolution, a buffer to extend the residence time, and finally obtains nanobubble fuel through depressurization and separation equipment. CN202111366716.X discloses a supply control system and method for oxygen-enriched micro / nanobubble fuel in engines, which obtains liquid-phase fuel containing nanobubbles through an oxygen-enriched micro / nanobubble fuel generation system, an oxygen-enriched micro / nanobubble fuel storage device, a pressure limiting valve, and an oil-gas separation device. However, all of the aforementioned patents require an excessively large oil-gas separator, making it impossible to generate nanobubble fuel online within the compact space of a gas turbine. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method and apparatus for online generation of nanobubble fuel, so as to improve the efficiency of converting dissolved gas into nanobubbles during the preparation of nanobubble fuel.

[0008] To achieve the above objectives, a first aspect of the present invention provides a method for online generation of nanobubble fuel, comprising the following steps:

[0009] 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.

[0010] 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.

[0011] According to the present invention, the gas is hydrogen or methane, and the gas is dehydrated before being injected into the preparation unit and has a pressure of 3.1 to 3.9 MPa; 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.

[0012] According to the present invention, the residence time of fuel oil in the jet-flow solvent is 2 to 10 seconds, and the number of jet-flow solvents connected in series satisfies the liquid residence time.

[0013] According to a preferred embodiment of the present invention, the residence time of fuel oil in the injection circulation solvent is set as follows:

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

[0015] Furthermore, during the dissolution process of liquid fuel oil in the jet-circulating solvent, the liquid Reynolds number of the jet-circulating solvent is 3400 to 34000, and the liquid velocity at the converging inlet end of the jet-circulating solvent is 4 to 40 m / s.

[0016] Furthermore, 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.

[0017] A second aspect of the present invention provides an apparatus for online generation of nanobubble fuel, comprising a preparation unit, a continuous fuel oil inlet disposed at the front end of the preparation unit, and a continuous nanobubble fuel oil outlet disposed at the rear end of the preparation unit, wherein the preparation unit comprises two or more stages of jet circulation dissolvers connected in series, and a swirling depressurizer connected to the rear end of the last stage jet circulation dissolver, wherein:

[0018] The front end of the jet-circulating solvent is a converging inlet, and the rear end is a circulating outlet. The fuel oil continuous inlet is connected to the converging inlet of the first-stage jet-circulating solvent, and the circulating outlet of the previous-stage jet-circulating solvent is connected to the converging inlet of the next-stage jet-circulating solvent. Each stage of the jet-circulating solvent has an inner cylinder, the front end of which corresponds to the converging inlet and the circulating outlet, respectively, and the interior of the jet-circulating solvent is divided into a forward flow area inside the inner cylinder and a return flow area outside the inner cylinder. In addition, the first-stage jet-circulating solvent also has a solvent gas inlet near the converging 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 ml. Attached Figure Description

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

[0026] Figure 2 is a schematic diagram of the multi-stage jet circulation melter in the online nanobubble fuel generation device of Figure 1, which is 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] As shown in Figure 1, 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] Liquid fuel oil is injected into the jet-circulating solvent 1 through the continuous fuel oil inlet 3 from the tapered inlet 11. The liquid velocity gradually increases, creating a jetting and negative pressure effect. The negative pressure draws in gas from the gas inlet 16 of the jet-circulating solvent 1, and the gas-liquid mixture enters the forward flow zone 14 inside the inner cylinder 13 under the jetting action. Since the inner cylinder 13 divides the jet-circulating solvent 1 into the forward flow zone 14 and the return flow zone 15, part of the gas-liquid mixture is discharged from the circulating outlet 12, and part enters the return flow zone 15, forming a circulating flow. During the jetting circulation process, the gas-liquid mass transfer area and liquid phase turbulence are enhanced, and the dissolution rate is significantly increased. At the same time, the return flow zone 15 prolongs the liquid residence time, making it easier for the liquid at the circulating outlet 12 to reach saturation.

[0035] Preferably, the diameter of the end channel of the tapered inlet 11 of the jet circulation melter 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.

[0036] 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 left end face of the inner cylinder 13 (corresponding to the end face of the converging inlet 11) 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.

[0037] The cyclone depressurizer 2 can enhance the generation of nanobubbles, and its principle is as follows:

[0038] Swirling flow fields exhibit unique velocity and pressure gradient distribution characteristics. The tangential velocity in a swirling flow field can generate significant centrifugal acceleration, which can be used to efficiently separate microbubbles from the liquid. Swirling flow fields display a pressure gradient characterized by high pressure at the edges and low pressure at the center. This pressure gradient is typically caused by the tangential velocity and is relatively uniform. The decompression rate in a swirling flow field does not change with position, exhibiting a stable decompression effect.

[0039] The cyclone depressurizer 2 can generate a stable depressurization effect, converting dissolved gas into bubbly gas. At the same time, under the action of centrifugal acceleration, it concentrates micron and millimeter-sized bubbles into the cyclone negative pressure zone and quickly separates them from the gas outlet 24 at the top. This can avoid the Ostwald ripening effect (the process of large bubbles absorbing small bubbles) on nanobubbles by large bubbles and increase 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 to 8 mm, and the diameter of the cyclone cavity 21 is 3 to 9 times the diameter of the tangential inlet 22.

[0041] The distance between the axis of the tangential inlet 22 and the top end face of the cyclone pressure reliever 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 liquid outlet 23 of the cyclone pressure reliever 2 is 10 to 50 times the diameter of the tangential inlet 22.

[0042] Figure 2 shows a second series connection configuration of two or more stages of jet circulation dissolvers 1 in the online nanobubble fuel generation device of the present invention. This differs from the configuration shown in Figure 1, where two or more stages of jet circulation dissolvers 1 are connected in series sequentially. The configuration shown in Figure 2 connects two or more stages of jet circulation dissolvers 1 in a vertically aligned manner. It is easy to understand that the rear end of the bottom-level jet circulation dissolver 1 is connected to a vortex pressure relief device 2, and the continuous fuel oil inlet 3 is connected to the tapered inlet 11 of the top-level first-stage jet circulation dissolver 1. The continuous nanobubble fuel oil outlet 4 is connected to the nanobubble fuel oil outlet 23 of the vortex pressure relief device 2.

[0043] Those skilled in the art will readily understand that, although the above examples illustrate multi-stage jet circulation melters in series front and rear and in series top and bottom, depending on the actual site conditions, a combination of front-to-back and series top and bottom configurations, or other possible series configurations, can be adopted as needed. This is obvious and all fall within the scope of this invention.

[0044] The method for generating nanobubble fuel online according to the present invention includes the following steps:

[0045] S1: Fuel oil is continuously injected into a preparation unit comprising two or more stages of jet circulation dissolvers 1 connected in series and a swirling pressure relief device 2. In the first stage jet circulation dissolver 1 of the preparation unit, the liquid flow rate gradually increases after entering the jet circulation dissolver 1 through the gradually narrowing inlet 11, forming a jetting and negative pressure effect, which draws the gas into the jet circulation dissolver 1 and makes it come into contact with the fuel oil and dissolves it. Then, it passes through the subsequent one or more stages of jet circulation dissolvers 1 connected in series in sequence. In each stage of jet circulation dissolver 1, a circulation is formed by the inner cylinder 13 inside the jet circulation dissolver, thereby mixing and dissolving the gas injected in the first stage multiple times.

[0046] S2: Fuel oil containing dissolved and undissolved gases enters the swirling pressure relief unit 2 of the preparation unit. Undissolved gases are separated from the swirling pressure relief unit 2 and returned to the intake area of ​​the jet circulation dissolver 1. The nanobubble fuel oil is continuously discharged from the preparation unit.

[0047] Using the above-described process of the present invention, the liquid fuel oil after swirl depressurization contains a certain concentration of nanobubbles, with a nanobubble concentration reaching 2×10⁻⁶. 8 ~5×10 8 per ml.

[0048] According to the present invention, the gas may be hydrogen or methane, and the gas should be dehydrated before being injected into the preparation unit and have a pressure of 3.1 to 3.9 MPa.

[0049] Furthermore, the fuel oil can be diesel, kerosene, ethanol, or other fuel oils. The residence time of the fuel oil in the jet-flow solvent 1 is 2–10 s; specifically, when the fuel oil temperature is -10 to 10°C, the residence time is 8–10 s; when the fuel oil temperature is 10–30°C, the residence time is 5–8 s; and when the fuel oil temperature is 30–90°C, 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 jet-flow solvents 1 connected in series should meet the liquid residence time requirements.

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

[0051] The parameter that reflects the degree of turbulence in the jet circulation is the liquid Reynolds number, and the expression for the liquid Reynolds number of the jet circulation is: Where D is the diameter of the converging inlet channel cross-section, and u is the liquid velocity at the end of the converging inlet. For the density of the liquid, This refers to the viscosity of the liquid.

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

[0053] In this invention, inside the cyclone pressure relief device 2, the tangential velocity of the liquid fuel oil containing dissolved gas is preferably 5–20 m / s, and the centrifugal acceleration is preferably 2500–40000 m / s. 2 The residence time of the liquid in the cyclone pressure relief device is preferably 0.08 to 1 s. Example 2

[0054] This embodiment provides an apparatus and method for online generation of nanobubble fuel. The apparatus 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. See Embodiment 1 for details.

[0055] The diameter of the end channel of the tapered inlet 11 of the jet flow dissolver 1 is 4 mm, the diameter of the forward flow region 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 region 15 is equal to 3 times the cross-sectional area of ​​the forward flow region 14.

[0056] The length of the inner cylinder 13 of the jet-flow dissolver 1 is 100 times the diameter of the end channel of the converging inlet 11, and the distance between the left end face of the inner cylinder 13 and the end section of the converging inlet 11 is 10 times the diameter of the end channel of the converging inlet.

[0057] The diameter of the tangential inlet 22 of the cyclone pressure reliever 2 is 2.5 mm, and the diameter of the cyclone cavity 21 is 8 times the diameter of the tangential inlet 22.

[0058] The distance between the axis of the tangential inlet 22 of the cyclone pressure reliever 2 and the top end face of the cyclone pressure reliever 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 reliever 2 is 30 times the diameter of the tangential inlet 22.

[0059] The online nanobubble fuel generation method of this embodiment includes the following steps:

[0060] S1: Fuel oil is continuously injected into a preparation unit comprising a three-stage series-connected jet circulation dissolver 1 and a swirling pressure relief device 2. In the first-stage jet circulation dissolver 1 of the preparation unit, the liquid flow rate gradually increases after entering the jet circulation dissolver 1 through the converging inlet 11, forming a jetting and negative pressure effect, which draws the gas into the jet circulation dissolver 1 and makes it come into contact with the fuel oil and dissolves it. Then, the gas passes through the subsequent two-stage series-connected jet circulation dissolvers 1 in sequence and is mixed and dissolved multiple times with the gas injected in the first stage.

[0061] S2: Fuel oil containing dissolved and undissolved gases enters the swirling pressure relief unit 2 of the preparation unit. Undissolved gases are separated from the swirling pressure relief unit 2 and returned to the intake area of ​​the jet circulation dissolver 1. The nanobubble fuel oil is continuously discharged from the preparation unit.

[0062] In this embodiment, methane is selected as the gas, which is dehydrated before being injected into the preparation unit and has a pressure of 6 MPa.

[0063] The liquid is diesel oil, and the residence time of the fuel oil in the injection circulation solvent 1 is 3 seconds, and the temperature of the fuel oil is 33 degrees Celsius.

[0064] The concentration of nanobubbles in nanobubble fuel oil increases with the increase of the pressure of the liquid feed, which is set to 4.5 MPa.

[0065] During the dissolution process of liquid fuel oil in the injection circulation solvent 1, the liquid Reynolds number of the injection circulation is 23000, and the liquid velocity at the end of the converging inlet 11 is 20m / s.

[0066] Liquid fuel oil containing dissolved gases is contained inside cyclone pressure relief unit 2, where the tangential velocity of the cyclone is 6.8 m / s and the centrifugal acceleration of the cyclone is 4600 m / s². 2 The residence time of the liquid in the cyclone pressure relief device 2 is 0.8s.

[0067] The length of a single jet-flow dissolver 1 is 0.8 m. Based on the known conditions: the liquid velocity at the end of the converging inlet 11 is 20 m / s; the diameter of the forward flow region 14 is 2.5 times the diameter of the end channel of the converging inlet 11; and the cross-sectional area of ​​the return flow region 15 is 3 times the cross-sectional area of ​​the forward flow region. It can be calculated that the residence time of liquid fuel in a single jet-flow dissolver 1 is 1 second. To achieve the requirement of a 3-second residence time for fuel oil in the jet-flow dissolver, this embodiment uses three jet-flow dissolvers 1 connected in series.

[0068] The three series-connected jet-flow dissolvers can be arranged in a straight line (front and back) or folded up and down according to the actual space conditions, as shown in Figure 2.

[0069] High-concentration nanobubble fuel oil was sampled and analyzed. Within one hour of sampling, the nanoparticle tracking analysis (NTA) method was used for measurement. The instrument model was Malvern NS300.

[0070] Using the method and apparatus of this embodiment, nanobubble diesel fuel can be prepared, and the measured concentration of nanobubbles is 3.6 × 10⁻⁶. 8 The number of cells / ml is shown in Table 1. Example 3

[0071] This embodiment is basically the same as embodiment 2, except that, based on embodiment 2, the number of jet circulation dissolvers is reduced to two, and then the same gas-liquid flow rate is used for the experiment.

[0072] This implementation condition means that the residence time of fuel oil in the injection circulation dissolver is reduced from 3s to 2s. The test results (Table 1) show that the nanobubble concentration is reduced to 2.1×10⁻⁶. 8 The concentration of nanobubbles per milliliter is lower than that of Example 2. However, it is still at 2 × 10⁻⁶. 8 ~5×10 8 Within the range of cells / ml. Example 4

[0073] This embodiment is basically the same as embodiment 2, except that, based on embodiment 2, the number of jet circulation dissolvers is reduced to one, and then the same gas-liquid flow rate is used for the experiment.

[0074] This implementation condition means that the residence time of fuel oil in the injection circulation dissolver is reduced from 3 seconds to 1 second. The test results (Table 1) show that the nanobubble concentration is reduced to 0.9 × 10⁻⁶. 8 The concentration of nanobubbles per milliliter was lower than that in Example 2, and lower than 2 × 10⁻⁶. 8 per ml. Example 5

[0075] This embodiment is basically the same as Embodiment 2, except that, based on Embodiment 2, the cyclone depressurizer is replaced with a gas-liquid separator with a liquid phase residence time of 4 minutes. The gas and liquid coming out of the gas-liquid separator are then mixed together to form a gas-liquid two-phase fuel. Then, the same nanobubble concentration test experiment is performed.

[0076] The test results (Table 1) show that the concentration of nanobubbles decreased to 0.5 × 10⁻⁶. 8 per ml.

[0077] Cause analysis: Because large bubbles cannot be separated quickly and the pressure drop 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. Example 6

[0078] This embodiment is basically the same as Embodiment 2, except that the liquid pressure is reduced to 1 MPa. The test results (Table 1) show that the nanobubble concentration is reduced to 0.2 × 10⁻⁶. 8 per ml.

[0079] Cause analysis: The reduced solubility of saturated gas leads to a decrease in the total number of molecules converted into nanobubbles. Example 7

[0080] This embodiment is basically the same as Embodiment 2, except that the pressure of the high-pressure tank is increased to 6 MPa, based on Embodiment 2. The test results (Table 1) show that the nanobubble concentration is increased to 4 × 10⁻⁶. 8 per ml.

[0081] Cause analysis: Increasing the solubility of saturated gas increases the total number of molecules converted into nanobubbles. Example 8

[0082] This embodiment is basically the same as embodiment 2, except that gas injection is omitted in embodiment 2.

[0083] This example serves as a blank sample for NTA testing of nanobubbles, confirming that the nanoparticles measured in Examples 2-7 and 9-10 are nanobubbles, not nanosolid particles. Example 9

[0084] This embodiment is basically the same as Embodiment 2, except that, based on Embodiment 2, the concentration of nanobubbles was measured 2 days after sampling. The test results are shown in Table 1. It can be seen that after 2 days, the concentration of nanobubbles decreased very little, demonstrating good stability. Example 10

[0085] This embodiment is basically the same as Embodiment 2, except that, based on Embodiment 2, the concentration of nanobubbles was measured 10 days after sampling. The test results are shown in Table 1. It can be seen that after 10 days, the concentration of nanobubbles decreased very little, demonstrating good stability. Example 11

[0086] This embodiment is basically the same as embodiment 2, except that the fuel oil temperature is changed from 33°C to 2°C based on embodiment 2. The test results are shown in Table 1.

[0087] The test results showed that the concentration of nanobubbles decreased to 0.65 × 10⁻⁶. 8 The concentration of nanobubbles is approximately 1 / mL. It is known that the lower the temperature, the slower the molecular diffusion, resulting in slower dissolution in the jet-circulating dissolver and slower desorption in the swirling depressurizer, ultimately leading to an excessively low concentration of nanobubbles. Example 12

[0088] This embodiment is basically the same as embodiment 2, except that, based on embodiment 2, the fuel oil temperature is changed from 33°C to 2°C, and the number of injection circulation solvents is increased from 3 to 9. The test results are shown in Table 1.

[0089] The test results showed that the concentration of nanobubbles was 3.5 × 10⁻⁶. 8 The concentration of nanobubbles is shown to be low. It is known that the lower the temperature, the slower the molecular diffusion, resulting in slower dissolution in the jet-circulating dissolver and slower desorption in the cyclone depressurizer, ultimately leading to an excessively low nanobubble concentration. Increasing the residence time from 3 s to 9 s compensates for the slow diffusion at low temperatures.

[0090] Table 1

[0091] Example 13

[0092] A combustion experiment was conducted in a gas turbine, with a liquid fuel flow rate of 2 L / min, which is the same as the fuel flow rate entering the swirl depressurizer in Examples 2-12.

[0093] Combustion experiments were conducted using the nanobubble fuel prepared in Example 2 and the fuel prepared in Example 8. The results are shown in Table 2.

[0094] Table 2: Combustion Experiment Data

[0095]

[0096] The results in Table 2 show that fuel exhaust gas with hydrogen nanobubbles has a lower NOx emission concentration and is more environmentally friendly. Example 14

[0097] A combustion experiment was conducted in a gas turbine, with a liquid fuel flow rate of 2 L / min, which is the same as the fuel flow rate entering the swirl depressurizer in Examples 2-12.

[0098] Hydrogen gas was injected into the liquid fuel at a rate of 0.1 L / min. Combustion experiments were conducted using the nanobubble fuel prepared in Example 2 and the gas-liquid two-phase mixed fuel prepared in Example 5. The results are shown in Table 3.

[0099] Table 3: Combustion Experiment Data

[0100]

[0101] The results in Table 3 show that fuel exhaust gas with hydrogen nanobubbles has a lower NOx emission concentration and is more environmentally friendly.

[0102] 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 principles of the present invention should be included within the protection scope of the present invention.

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.

2. The method according to claim 1, characterized in that, 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.

3. 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.

4. The method according to claim 3, 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.

5. 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.

6. 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.

7. 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).

8. The apparatus according to claim 7, 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).

9. The apparatus according to claim 7, 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).

10. The apparatus according to claim 7, 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).

11. The apparatus according to claim 7, characterized in that, The distance between the axis of the tangential inlet (22) and the top end face of the cyclone pressure reliever (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 liquid outlet (23) of the cyclone pressure reliever (2) is 10 to 50 times the diameter of the tangential inlet (22).

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