A high-concentration nanobubble fuel preparation method and device

Abstract

This invention discloses a method for preparing high-concentration nanobubble fuel oil. The method employs a batch preparation approach, where fuel oil is added in batches to a preparation unit comprising a high-pressure tank, a jet-flow dissolver, and a cyclone depressurizer. The jet-flow dissolver, which forms a liquid and gas circulation loop with the high-pressure tank, injects gas to dissolve the fuel oil, thus preparing high-concentration nanobubble fuel oil. After preparation, the high-concentration nanobubble fuel oil is depressurized in batches by the cyclone depressurizer and discharged into the fuel tank of a gas turbine. This invention also discloses a corresponding preparation apparatus. The high-concentration nanobubble fuel oil prepared by this invention can achieve a nanobubble concentration of 1×10⁻⁶. 8 ~1×10 9 It has a density of 1 nanobubbles per milliliter and good stability; its nanobubbles can remain stable for several days or even tens of days.

Description

Technical Field

[0001] This invention belongs to the field of chemical machinery technology, specifically, it relates to a method and apparatus for preparing high-concentration nanobubble fuel. Background Technology

[0002] Heavy-duty gas turbines are a significant indicator of a nation's heavy industry capabilities. When gas turbines are applied in strategic sectors such as transportation power, the uncertainty of fuel supply presents a challenge. Flexible fuel gas turbine technology is a major strategic need for my country. Blending hydrogen into the fuel can alter the hydrocarbon ratio, catering to the demands of wider load ranges and flexible fuel availability.

[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] In existing nanobubble mixture preparation technologies, the continuous phase is mostly water, and the dispersed phase is hydrophobic gases such as air and hydrogen. Generally, surfactants are added to the water to improve the stability of the microbubbles. This type of technology relies on the reinforcing effect of impurities and charges on the bubble surface on interfacial stability. Fuel oils, represented by diesel, and fuels, represented by hydrogen, do not contain hydrophilic polar structures, so traditional nanobubble preparation methods based on aqueous surfactants cannot guide the preparation of nanobubble fuel oils. To date, the high-concentration preparation of nanobubbles from non-aqueous, surfactant-free systems (such as fuel oil) remains a significant challenge.

[0006] 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.

[0007] The concentration of nanobubbles exhibits a certain correlation with the concentration of dissolved gases, and the method of obtaining nanobubble fuel through dissolved gas decompression has attracted widespread attention. CN202010665795.3 provides a compression-type nano-hydrogen bubble diesel fuel preparation apparatus, method, and application. Hydrogen and diesel are mixed at a predetermined pressure, and then the hydrogen / diesel solution in the compression cylinder is released to an oil / gas separator for separation to obtain nano-hydrogen bubble / diesel fuel. CN201910579114.9 discloses a counter-mixed nano-hydrogen bubble diesel fuel preparation apparatus, method, and application, which uses a corrugated pipe wall to enhance hydrogen dissolution and a buffer to extend the residence time, ultimately obtaining nanobubble fuel through decompression separation. CN202111366716.X provides a supply control system and method for oxygen-enriched micro / nanobubble fuel for engines, obtaining 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 separator.

[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 metastablebulk nanobubbles in water by external electric fields. Science Advances 6(14)). With the increase of the number of cycles, the concentration of nanobubbles is expected to increase further. The patents cited above are all for the online preparation of nanobubble fuel oil, which lacks the effect of cyclic enrichment and cannot achieve the preparation of high-concentration nanobubbles. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-concentration nanobubble fuel oil preparation device and process to improve the nanobubble concentration and storage stability of fuel oil.

[0010] To achieve the above objectives, in a first aspect, the present invention provides a method for preparing high-concentration nanobubble fuel oil. The method employs a batch preparation approach, in which fuel oil is added in batches to a preparation unit comprising a high-pressure tank, a jet-flow dissolver, and a swirling depressurizer. The jet-flow dissolver, which forms a liquid and gas circulation with the high-pressure tank, is used to spray and dissolve the inhaled gas, thus preparing high-concentration nanobubble fuel oil. After preparation, the high-concentration nanobubble fuel oil is discharged to the gas turbine fuel tank in batches after being depressurized by the swirling depressurizer.

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

[0012] S1: 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 1-5 MPa;

[0013] S2: Turn on the booster pump to accelerate the liquid fuel oil in the injection circulation solvent to form a jetting and negative pressure effect, draw in 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. The undissolved gas rises to the gas phase area at the top of the high pressure tank, and under the suction of the injection circulation solvent, it comes into contact with the fuel oil again in the gas circulation loop and dissolves. This cycle of contact and dissolution continues.

[0014] S3: After being prepared by circulation for 30 to 120 minutes, the fuel oil containing a high concentration of nanobubbles is discharged into the gas turbine oil tank after being depressurized by the cyclone depressurizer.

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

[0016] According to the present invention, 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.

[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℃, the circulation time is 90 to 120 minutes; when the fuel oil temperature is 10 to 30℃, the circulation time is 60 to 90 minutes; when the fuel oil temperature is 30 to 90℃, the circulation time is 30 to 60 minutes.

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

[0020] According to a preferred embodiment of the present invention, in step S2, during the dissolution process of liquid fuel oil in the jet-circulating dissolver in contact with gas, 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.

[0021] According to a preferred embodiment of the present invention, in step S2, inside the cyclone pressure relief device, the tangential velocity of the liquid fuel oil containing dissolved gas 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.

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

[0023] A second aspect of the present invention provides a high-concentration nanobubble fuel oil preparation apparatus, comprising a high-pressure tank, a jet-circulating dissolver, and a swirling depressurizer, wherein:

[0024] The interior of the high-pressure tank has a gas phase region at the top and a liquid phase region at the bottom; 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 is provided with a fuel oil replenishment inlet; and the upper and lower side walls corresponding to the gas phase region and the liquid phase region of the high-pressure tank are respectively provided with a return gas inlet and a return fuel oil inlet.

[0025] The jet-flow solvent has a converging inlet and a recirculating outlet, which are respectively connected to the liquid phase outlet and the return fuel oil inlet of the high-pressure tank through pipelines, thus forming a liquid circulation loop. A booster pump is provided on the circulation pipeline at the front end of the converging inlet. The jet-flow solvent also has a gas inlet near the converging inlet. The gas phase outlet of the high-pressure tank is connected to the gas inlet of the jet-flow solvent through a pipeline, thus forming a gas circulation loop. The jet-flow solvent has an inner cylinder inside. The front and rear ends of the inner cylinder correspond to the converging inlet and the recirculating outlet, respectively, and the interior of the jet-flow solvent is divided into a forward flow area inside the inner cylinder and a return flow area outside the inner cylinder.

[0026] The swirling pressure relief device is installed on the pipeline at the rear end of the booster pump. Its main body is a swirling cavity. The upper side wall of the swirling cavity is provided with a tangential inlet, and the top and bottom are respectively provided with a gas outlet and a nano-bubble fuel oil outlet.

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

[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 reliever is 2 to 8 mm, and the diameter D of the cyclone cavity is 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 face of the cyclone pressure reliever 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 nanobubble fuel oil outlet of the cyclone pressure reliever 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 tangential inlet front end of the cyclone pressure relief device for discharging 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 cyclone pressure relief device for quality control of the discharged high-concentration nanobubble fuel oil.

[0032] According to the present invention, the gas outlet of the cyclone depressurizer is further connected to the return gas inlet of the high-pressure tank via a pipeline, thereby realizing the reuse of the depressurized and separated gas.

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

[0034] 1. The high-concentration nanobubble fuel oil prepared by this invention can achieve a nanobubble concentration of 1×10⁻⁶. 8 ~1×10 9 per milliliter.

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

[0036] 3. Fuel oil containing a high concentration of nano-bubbles can enhance combustion and reduce pollution emissions for several days. Attached Figure Description

[0037] Figure 1 This is a process flow diagram of the high-concentration nanobubble fuel oil preparation device of the present invention.

[0038] Figure 2 for Figure 1 A schematic diagram of the structure of a medium-jet circulating dissolver.

[0039] Figure 3 for Figure 1 A schematic diagram of the structure of a vortex pressure relief device.

[0040] Figure 4 The cycle time required to reach the maximum nanobubble concentration is shown at different temperatures (32°C and 22°C). Detailed Implementation

[0041] 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.

[0042] Example 1: Apparatus and method for preparing high-concentration nanobubble fuel oil

[0043] 1.1 High-concentration nanobubble fuel oil preparation device

[0044] like Figure 1 As shown, the high-concentration nanobubble fuel oil preparation device of this embodiment includes a high-pressure tank 1, a jet circulation melter 2, and a swirling depressurizer 3, wherein:

[0045] 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 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 respectively provided with a return gas inlet 16 and a return fuel oil inlet 17.

[0046] Combination Figure 2 As shown, the jet-flow solvent 2 has a tapered inlet 21 and a recirculation outlet 22, which are respectively 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. A booster pump 4 is provided on the circulation pipeline at the front end of the tapered inlet 21. The jet-flow solvent 2 also has a jet-flow solvent gas inlet 23 near the tapered inlet 21. The gas phase outlet 13 of the high-pressure tank 1 is connected to the jet-flow solvent gas inlet 23 through a pipeline, thereby forming a gas circulation loop. Preferably, the jet-flow solvent 2 has an inner cylinder 24 inside. 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 recirculation outlet 22, respectively, and divide the interior of the jet-flow solvent 2 into a forward flow region 26 inside the inner cylinder 24 and a return flow region 25 outside the inner cylinder 24.

[0047] Combination Figure 3 As shown, the swirling pressure relief device 3 is installed on the pipeline at the rear end of the booster pump 4. Its main body is a swirling cavity 31. The upper side wall of the swirling cavity 31 is provided with a tangential inlet 32, and the top and bottom are respectively provided with a gas outlet 33 and a nano bubble fuel oil outlet 34.

[0048] Combination Figure 2As shown, preferably, the channel diameter at the end of the tapered inlet 21 of the jet circulation melter 2 is 1-5 mm, the diameter of the forward flow region 26 inside the inner cylinder 24 is 1.5-3 times the channel diameter at the end of the tapered inlet 21, and the cross-sectional area of ​​the return flow region 25 is 0.8-9 times the cross-sectional area of ​​the forward flow region 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 at 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 reliever 3 is 2-8 mm, and the diameter D of the cyclone cavity 31 is 3-9 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 face of the cyclone pressure reliever 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 reliever 3 is 10 to 50 times the diameter of the tangential inlet 32.

[0052] Furthermore, a safety valve 5 is installed on the external pipeline of the gas phase outlet 13 at the top of the high-pressure tank 1 to discharge excess gas. A nanobubble fuel oil discharge valve 6 is installed on the pipeline at the front end of the tangential inlet 31 of the cyclone depressurizer 3 to discharge the prepared high-concentration nanobubble fuel oil in batches. A sampling port 7 is installed on the external pipeline of the nanobubble fuel oil outlet 34 of the cyclone depressurizer 3 for quality control of the discharged high-concentration nanobubble fuel oil. The jet circulation dissolver gas inlet 23 of the jet circulation dissolver 2 can be connected to different gases, such as methane, hydrogen, and air, as needed. The gas outlet 33 of the cyclone depressurizer 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 depressurized 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] Fuel oil liquid is injected through the converging inlet 21 of the jet-circulating solvent 2, where the liquid velocity gradually increases, creating a jetting and negative pressure effect. The negative pressure draws gas in through the gas inlet 23 of the jet-circulating solvent 2, and the gas-liquid mixture enters the forward flow region 26 inside the inner cylinder 24 under the jetting action. Since the inner cylinder 24 divides the jet-circulating solvent 2 into the forward flow region 26 and the return flow region 25, part of the gas-liquid mixture is discharged from the circulating outlet 22, while the rest enters the return flow region 25 between the outside of the inner cylinder 24 and the inner wall of the jet-circulating solvent 2, forming a circulating flow. During the jetting circulation process, the gas-liquid mass transfer area and liquid phase turbulence are enhanced, significantly increasing the dissolution rate. Simultaneously, the return flow region 25 prolongs the liquid's residence time, making it easier for the liquid at the circulating outlet 22 to reach saturation, thereby enhancing gas dissolution.

[0055] In this embodiment, combined with Figure 3 As shown, the principle of the cyclone depressurizer 3 enhancing nanobubble generation is as follows:

[0056] 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 characteristic of 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.

[0057] The swirling pressure relief device 3 can generate a stable pressure relief effect, converting dissolved gas into gas bubbles. At the same time, under the action of centrifugal acceleration, it concentrates micron and millimeter-sized bubbles into the central swirling negative pressure zone 35 and quickly separates them from the gas outlet 33 at the top. This can avoid the Ostwald ripening effect (the process of large bubbles absorbing small bubbles) on nanobubbles by large bubbles, thereby increasing the concentration of nanobubbles remaining in the liquid.

[0058] 1.2 Preparation method of high-concentration nanobubble fuel oil

[0059] The high-concentration nanobubble fuel oil preparation method of this embodiment adopts a batch preparation method. The fuel oil is added to the preparation unit, which includes a high-pressure tank, a jet circulation dissolver and a swirling depressurizer, in batches. The jet circulation dissolver, which forms a liquid circulation and a gas circulation with the high-pressure tank, forms a jet, and the gas is drawn in and dissolved. The high-concentration nanobubble fuel oil is prepared in a cycle. After the high-concentration nanobubble fuel oil is prepared, it is discharged to the gas turbine oil tank in batches after being depressurized by the swirling depressurizer.

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

[0061] S1: 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 1-5 MPa.

[0062] S2: The booster pump is activated, causing the liquid fuel oil to be accelerated in the injection circulation dissolver, creating a jetting and negative pressure effect. This draws in gas, which then dissolves in the liquid. The dissolved gas then returns to the liquid phase region at the bottom of the high-pressure tank via the liquid circulation loop. Undissolved gas rises to the gas phase region at the top of the high-pressure tank, where it is drawn in by the injection circulation dissolver and dissolves again in the gas circulation loop. This cycle of contact and dissolution continues. Excess gas is discharged to the exhaust gas treatment unit via the safety valve.

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

[0064] In this embodiment, the gas can 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, or other fuel oils, and the circulation time of each batch of fuel oil in the preparation unit is 30–120 minutes. Specifically, when the fuel oil temperature is -10 to 10°C, the circulation time is 90–120 minutes; when the fuel oil temperature is 10–30°C, the circulation time is 60–90 minutes; and when the fuel oil temperature is 30–90°C, the circulation time is 30–60 minutes. The lower the temperature, the slower the molecular diffusion rate of gas in the fuel oil, and the longer the required circulation time.

[0066] Using the method of this invention, the concentration of nanobubbles in fuel oil increases with the increase of the pressure in the high-pressure tank, which is derived from gas pressure and is set to 1–5 MPa. While a higher pressure results in a higher concentration of nanobubbles, it also increases the energy consumption for nanobubble preparation. Therefore, the optimized high-pressure tank pressure is 2–3 MPa.

[0067] The parameter that reflects the degree of turbulence in the jet circulation is the liquid Reynolds number. The expression for the liquid Reynolds number of the jet circulation is: Where D is the cross-sectional diameter of the converging inlet of the jet circulation dissolver, 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.

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

[0069] Based on the principle of enhancing nanobubble generation using a cyclone depressurizer, in this embodiment, the liquid fuel oil containing dissolved gases is placed inside the cyclone depressurizer, where the tangential velocity of the cyclone is 5–20 m / s and the centrifugal acceleration of the cyclone is 2500–40000 m / s. 2 The residence time of the liquid in the cyclone pressure relief device is 0.08 to 1 second.

[0070] According to the method of the present invention, during the preparation of nanobubbles in fuel cycle, 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, and the nanobubble fuel oil is transported to the gas turbine oil tank under the pressure of the high-pressure tank.

[0071] Using the method of this invention, the concentration of nanobubbles prepared is 1×10⁻⁶. 8 ~1×10 9 per milliliter. Example 2

[0072] As an application embodiment of the present invention, the process flow is as follows: Figure 1 A method for preparing high-concentration nanobubble diesel fuel is disclosed. The method involves batch preparation, in which fuel oil is added in batches to a preparation unit (high-concentration nanobubble fuel oil preparation device of Example 1) including a high-pressure tank 1, a jet circulation dissolver 2 and a swirling depressurizer 3. The jet circulation dissolver 2 forms a jet, and the gas is drawn in and dissolved. The process is repeated to prepare high-concentration nanobubble fuel oil. After preparation, the high-concentration nanobubble fuel oil is discharged to the gas turbine oil tank in batches after being depressurized by the swirling flow.

[0073] Specifically, the preparation method includes the following steps:

[0074] S1: 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.

[0075] S2: The booster pump is activated, causing the liquid fuel oil to be accelerated in the injection circulation dissolver, creating a jetting and negative pressure effect. This draws in gas, which then comes into contact with and dissolves the fuel oil. The dissolved gas then returns to the liquid phase region at the bottom of the high-pressure tank. Undissolved gas rises to the gas phase region at the top of the high-pressure tank, where it is again drawn in by the injection circulation dissolver and dissolved by the fuel oil. This cycle of contact and dissolution continues. Excess gas is discharged through the safety valve to the exhaust gas treatment unit.

[0076] S3: After the set cycle preparation time, the fuel oil containing a high concentration of nanobubbles is depressurized by the cyclone depressurizer and discharged into the gas turbine fuel tank. The large bubbles generated during the depressurization process are separated by the cyclone depressurizer and returned to the gas phase region at the top of the high-pressure tank.

[0077] In this embodiment, hydrogen is selected as the gas, and it undergoes dehydration treatment before being injected into the preparation unit, and has a pressure of 4 MPa.

[0078] The liquid is diesel oil, the temperature is 32℃, and the circulation time of each batch of fuel oil in the preparation unit is 60 min.

[0079] The pressure in the high-pressure tank comes from the gas pressure, and the pressure in the high-pressure tank is set to 2 MPa.

[0080] During the contact dissolution process of liquid fuel oil with gas in the jet-circulating dissolver 2, the liquid Reynolds number of the jet-circulating flow is 23000, and the liquid velocity at the end of the converging inlet 21 is 20 m / s.

[0081] Liquid fuel oil containing dissolved gases is contained inside cyclone pressure relief unit 3, 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 3 is 0.8s.

[0082] In the preparation unit, the diameter of the end channel of the tapered inlet 21 of the jet circulating dissolver 2 is 4 mm, the diameter of the forward flow region 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 region 25 is equal to 3 times the cross-sectional area of ​​the forward flow region 26.

[0083] The length of the inner cylinder 24 of the jet-flow dissolver 2 is 100 times the diameter of the end channel of the converging inlet 21, and the distance between the right end face of the inner cylinder 24 and the end section of the converging inlet 21 is 10 times the diameter of the end channel of the converging inlet 21.

[0084] The diameter of the tangential inlet 32 ​​of the cyclone pressure reliever 3 is 2.5 mm, and the diameter D of the cyclone cavity 31 is equal to 8 times the diameter of the tangential inlet 32.

[0085] The distance L1 between the axis of the tangential inlet 32 ​​of the cyclone pressure reliever 3 and the top end face of the cyclone pressure reliever 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 reliever 3 is 30 times the diameter of the tangential inlet 32.

[0086] During the preparation of nanobubbles in the fuel cycle, 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, and the nanobubble fuel oil can be transported to the gas turbine oil tank under the pressure of the high-pressure tank 1.

[0087] High-concentration nanobubble fuel oil was sampled and analyzed through sampling port 7. Within one hour of sampling, the nanoparticle tracking analysis (NTA) method was used for measurement. The instrument model was Malvern NS300.

[0088] Measurement results show that using the apparatus and process described in Example 1 to prepare nanobubble diesel can significantly increase the nanobubble concentration, reaching 7.8 × 10⁻⁶. 8 The number of cells per milliliter is shown in Table 1. Example 3

[0089] Based on Example 2, the inner cylinder 24 of the jet circulation melter 2 was removed, and the tapered inlet 21 of the jet circulation melter 2 was replaced with a straight pipe inlet. The liquid velocity at the straight pipe inlet was reduced to 3 m / s (less than 4 m / s). Then, an experiment was conducted with the same gas-liquid flow rate. The results showed that the nanobubble concentration was reduced to 1.1 × 10⁻⁶. 8 The concentration of nanobubbles per milliliter is lower than that of Example 2.

[0090] Cause analysis: The lack of jet circulation to enhance dissolution results in a slow mass transfer rate and a low concentration of dissolved gas, leading to a low concentration of nanobubbles. Example 4

[0091] Based on Example 2, the cyclone depressurizer 3 was replaced with a gas-liquid separator with a liquid phase residence time of 4 minutes, and experiments were conducted with the same gas-liquid flow rate. The results showed that the nanobubble concentration decreased to 0.7 × 10⁻⁶. 8 per milliliter.

[0092] Cause analysis: Because large bubbles cannot be separated quickly and the depressurization rate drops suddenly, there is an Ostwald ripening effect. The process of large bubbles absorbing small bubbles reduces the concentration of nanobubbles in the liquid. Example 5

[0093] Based on Example 2, the pressure in high-pressure tank 1 was reduced to 0.5 MPa, and the results showed that the nanobubble concentration decreased to 0.5 × 10⁻⁶. 8 per milliliter.

[0094] Cause analysis: The reduced solubility of saturated gas leads to a decrease in the total number of molecules converted into nanobubbles. Example 6

[0095] Based on Example 2, the pressure in high-pressure tank 1 was increased to 3 MPa, and the results showed that the nanobubble concentration increased to 8.5 × 10⁻⁶. 8 per milliliter.

[0096] Cause analysis: Increasing the solubility of saturated gas increases the total number of molecules converted into nanobubbles. However, since the concentration of nanobubbles is measured at atmospheric pressure, and the fuel is also stored at atmospheric pressure, simply increasing the pressure of the high-pressure tank will not proportionally increase the concentration of nanobubbles at atmospheric pressure. Example 7

[0097] Based on Example 2, after completing the following steps, the gas injection is turned off.

[0098] "Fuel oil is added to the preparation unit in batches, and after the nanobubble fuel oil is prepared, it is discharged to the gas turbine fuel tank in batches. In the preparation unit, the fuel oil is first stored in the high-pressure tank 1, and then high-pressure gas is injected to quickly increase the pressure of the high-pressure tank 1 to 2 MPa, and the booster pump 4 is turned on." Then the gas injection is turned off, and after 60 minutes of cyclic preparation, the nanobubble fuel oil discharge valve 6 is opened, and samples are taken through the sampling port 7.

[0099] This comparative example serves as a blank sample for NTA testing of nanobubbles, confirming that the nanoparticles measured in Examples 2-6 and 8-9 are nanobubbles, not nanosolid particles. Example 8

[0100] Based on Example 2, the concentration of nanobubbles was measured 2 days after sampling, and the results are shown in Table 1. Example 9

[0101] Based on Example 2, the concentration of nanobubbles was measured 10 days after sampling, and the results are shown in Table 1. Example 10

[0102] Based on Example 2, diesel was replaced with aviation kerosene, and the concentration of nanobubbles was measured. The results are shown in Table 1. The results show that the concentration of nanobubbles increased slightly, possibly because hydrogen has a higher solubility in kerosene. Example 11

[0103] Based on Example 2, the diesel fuel was replaced with an 80% (w / w) ethanol solution, and the results are shown in Table 1. The results show that the concentration of nanobubbles decreased slightly, possibly because hydrogen has low solubility in ethanol. Example 12

[0104] Based on Example 2, hydrogen was replaced with methane, and the test results are shown in Table 1. The results show that the concentration of nanobubbles decreased slightly, possibly because methane has low solubility in diesel fuel. Example 13

[0105] Based on Example 2, hydrogen was replaced with air, and the test results are shown in Table 1. The results show that the concentration of nanobubbles remained almost unchanged, and the two gas types, hydrogen and air, had little effect on the concentration of nanobubbles.

[0106] Table 1: Test Results

[0107] Example 14

[0108] 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 measured. The results are as follows: Figure 4 As shown.

[0109] Figure 4 The results showed that the time to reach the maximum nanobubble concentration increased from 6 min to 70 min. The lower temperature resulted in a longer residence time, but the maximum nanobubble concentration remained basically unchanged. Example 15

[0110] A combustion experiment was conducted in a gas turbine with a liquid fuel flow rate of 2 L / min. Diesel fuels obtained in Examples 9 and 7 were used respectively. The experimental results are shown in Table 2 below.

[0111] Table 2: Combustion Experiment Data

[0112]

[0113] As shown in Table 2, fuels with hydrogen nanobubbles have lower NOx emission concentrations in their exhaust gases, making them more environmentally friendly.

[0114] 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 high-concentration nanobubble fuel oil preparation device, characterized in that, It includes a high-pressure tank (1), a jet-flow dissolver (2), and a swirling pressure reliever (3), wherein: The interior of the high-pressure tank (1) is divided into 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). 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). The jet-flow dissolver (2) has a tapered inlet (21) and a recirculation outlet (22), which are respectively 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. A booster pump (4) is provided on the circulation pipeline at the front end of the tapered inlet (21). The jet-flow dissolver (2) is also provided with a jet-flow dissolver gas inlet (23) near the tapered inlet (21). The high-pressure tank (1) The gas phase outlet (13) is connected to the gas inlet (23) of the jet circulation melter through a pipeline, thereby forming a gas circulation loop; the jet circulation melter (2) is provided with an inner cylinder (24), the front and rear ends of which correspond to the tapered inlet (21) and the circulation outlet (22) respectively, and the interior of the jet circulation melter (2) is divided into the forward flow area (26) inside the inner cylinder (24) and the return flow area (25) outside the inner cylinder (24); The swirling pressure relief device (3) is installed on the pipeline at the rear end of the booster pump (4). Its main body is a swirling cavity (31). The upper side wall of the swirling cavity (31) is provided with a tangential inlet (32), and the top and bottom are respectively provided with a gas outlet (33) and a nano bubble fuel oil outlet (34).

2. The preparation apparatus according to claim 1, characterized in that, The diameter of the channel at the end of the tapered inlet (21) of the jet flow dissolver (2) is 1 to 5 mm, the diameter of the forward flow region (26) inside the inner cylinder (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 region (25) is 0.8 to 9 times the cross-sectional area of ​​the forward flow region (26).

3. The preparation apparatus according to claim 1, characterized in that, The length of the inner cylinder (24) of the jet flow 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 at the end of the tapered inlet (21) is 2 to 20 times the channel diameter at the end of the tapered inlet (21).

4. The preparation apparatus according to claim 1, characterized in that, The diameter of the tangential inlet (32) of the swirling pressure reliever (3) is 2 to 8 mm, and the diameter D of the swirling cavity (31) is 3 to 9 times the diameter of the tangential inlet (32).

5. The preparation apparatus according to claim 1, characterized in that, The distance L1 between the axis of the tangential inlet (32) and the top end face of the cyclone pressure reliever (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 nanobubble fuel oil outlet (34) of the cyclone pressure reliever (3) is 10 to 50 times the diameter of the tangential inlet (32).

6. The preparation apparatus according to claim 1, characterized in that, The swirling pressure reliever (3) has a nanobubble fuel oil discharge valve (6) on the front end of the tangential inlet (32) for discharging the prepared high-concentration nanobubble fuel oil in batches; the swirling pressure reliever (3) has a sampling port (7) on the external pipe of the nanobubble fuel oil outlet (34) for quality control of the discharged high-concentration nanobubble fuel oil.

7. The preparation apparatus according to claim 1, characterized in that, The gas outlet (33) of the cyclone depressurizer (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 depressurized and separated gas.

8. A method for preparing high-concentration nanobubble fuel oil, using the preparation apparatus described in claim 1, characterized in that, The preparation method adopts a batch preparation approach, in which fuel oil is added in batches into the preparation unit including a high-pressure tank, a jet circulation dissolver, and a swirling depressurizer. The jet circulation dissolver, which forms a liquid and gas circulation with the high-pressure tank, is sprayed to draw in gas for contact dissolution, and high-concentration nanobubble fuel oil is prepared in a cyclical manner. After the high-concentration nanobubble fuel oil is prepared, it is discharged to the gas turbine oil tank in batches after being depressurized by the swirling depressurizer. 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.

9. The preparation method according to claim 8, characterized in that, Includes the following steps: S1: 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 1-5 MPa; S2: Turn on the booster pump to accelerate the liquid fuel oil in the injection circulation solvent to form a jetting and negative pressure effect, draw in 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. The undissolved gas rises to the gas phase area at the top of the high pressure tank, and under the suction of the injection circulation solvent, it comes into contact with the fuel oil again in the gas circulation loop and dissolves. This cycle of contact and dissolution continues. S3: After being prepared by circulation for 30 to 120 minutes, the fuel oil containing a high concentration of nanobubbles is discharged into the gas turbine oil tank after being depressurized by the cyclone depressurizer.

10. The preparation method according to claim 9, characterized in that, In step S1, the pressure of the high-pressure tank is controlled at 2-3 MPa.

11. The preparation method according to claim 8, characterized in that, The cycle time for each batch of fuel oil in the preparation unit is as follows: When the fuel oil temperature is -10 to 10°C, the circulation time is 90 to 120 minutes. When the fuel oil temperature is 10-30℃, the circulation time is 60-90 minutes; When the fuel oil temperature is 30-90℃, the circulation time is 30-60 minutes.

12. The preparation method according to claim 9, characterized in that, In step S2, excess gas is discharged to the exhaust gas treatment unit through a safety valve.

13. The preparation method according to claim 9, characterized in that, In step S2, during the dissolution process of liquid fuel oil in the injection circulation solvent, the liquid Reynolds number of the injection circulation is 3400 to 34000, and the liquid velocity at the converging inlet end of the injection circulation solvent is 4 to 40 m / s.

14. The preparation method according to claim 9, characterized in that, In step S2, inside the cyclone pressure relief device, 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.

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

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