Carbon hydrogen fuel oxidation coking accelerated test method based on multi-parameter synergistic reinforcement

Abstract

The present application relates to the technical field of hydrocarbon fuel thermal oxidation stability test, and discloses a hydrocarbon fuel oxidation coking accelerated test method based on multi-parameter synergistic reinforcement, which comprises the following steps: oxygen is introduced into the hydrocarbon fuel through a microporous dispersion device to make the dissolved oxygen concentration in the fuel reach 30 ppm to 50 ppm; the oxygen-containing fuel is pumped into a reaction tube with an inner diameter of 4.5 mm to 5.0 mm and a length of 80 cm at a flow rate of 0.08 g / s to 0.12 g / s; the oxidation coking reaction is carried out under the conditions of an oil temperature of 450 DEG C to 500 DEG C at the outlet of the reaction tube and a pressure of 3.5 MPa; the carbon deposition mass on the inner wall of the reaction tube is quantified by adopting a pipeline carbon burning method; and the suspended carbon particle mass is collected and weighed through a rear-end filter. The present application realizes the method of accelerated test and quantitative evaluation under the oxidation coking flow state through the synergistic control of three parameters of dissolved oxygen concentration, flow rate and pipe diameter.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon hydrocarbon fuel thermal oxidation stability test, and in particular relates to a carbon hydrocarbon fuel oxidation coking accelerated test method based on multi-parameter synergistic reinforcement. BACKGROUND

[0002] The oxidation coking of carbon hydrocarbon fuel (aviation fuel, lubricating oil, etc.) occurring in the high-temperature fuel supply system is one of the main reasons for the reliability decline of the aero-engine. The oxidation coking particles accumulate in the pipeline, not only increase the flow resistance and reduce the heat transfer efficiency, but also directly block the oil way when serious, which threatens the flight safety.

[0003] The current industry standard ASTM D3241 represents the coking test method which has fundamental limitations. Firstly, efficiency and precision are difficult to balance: under conventional conditions (300℃, 0.4g / s flow rate, Φ2mm tube), it takes 72 hours to accumulate 5-8mg of coking amount, and the weighing error caused by trace coking is >30%, which cannot meet the time efficiency demand of fuel batch inspection for aircraft engine manufacturers. Secondly, the coking type cannot be distinguished: the traditional method can only obtain the total coking amount, but the generation mechanism and engineering hazards of the pipe wall deposited carbon (causing local overheating) and the suspended carbon particles (causing filter blockage) are completely different.

[0004] In view of the above defects, the existing improvement schemes have not broken through the contradiction between "efficiency and authenticity". The online detection optimization scheme (such as flow resistance method, thermal resistance method) shortens the test period, but can only indirectly calculate the equivalent coking thickness, and cannot separate the deposited carbon and suspended carbon components; the external field intervention means (such as the electric field suppression method of patent CN201810338543A) changes the free radical reaction path due to the introduction of non-physical conditions, which leads to the deviation of the graphitization degree of coking from the actual situation. The core contradiction is that the existing technology either sacrifices authenticity for efficiency (ultra-high temperature / external field interference), or sacrifices efficiency to maintain authenticity (long period / low coking amount), and a rapid evaluation system that conforms to the intrinsic coking law of fuel has not been established. In view of the above defects, the existing improvement schemes have not broken through the contradiction between "efficiency and authenticity". SUMMARY

[0005] In view of the above defects in the prior art, the present application provides a carbon hydrocarbon fuel oxidation coking accelerated test method based on multi-parameter synergistic reinforcement, which realizes accelerated test and quantitative evaluation under the flow state of oxidation coking by synergistic regulation of three parameters of dissolved oxygen concentration, flow rate and pipe diameter, and is suitable for rapid stability evaluation of aviation fuel, biodiesel, lubricating oil and other fuels.

[0006] In order to achieve the above application purposes, the technical scheme adopted by the present application is as follows:

[0007] A carbon hydrocarbon fuel oxidation coking accelerated test method based on multi-parameter synergistic reinforcement, comprising the following steps:

[0008] Dissolve oxygen into the hydrocarbon fuel by the microporous dispersion device to reach a concentration of 30 ppm to 50 ppm;

[0009] Pump the oxygen-containing fuel into a reaction tube with an inner diameter of 4.5 mm to 5.0 mm and a length of 80 cm at a flow rate of 0.08 g / s to 0.12 g / s;

[0010] Perform the oxidation coking reaction at an oil temperature of 450℃ to 500℃ and a pressure of 3.5 MPa at the outlet of the reaction tube;

[0011] Quantify the deposited carbon mass on the inner wall of the reaction tube by the pipeline carbon burning method;

[0012] Collect and weigh the suspended carbon particle mass by the rear-end filter.

[0013] Further, the microporous dispersion device is a bubble stone.

[0014] Further, the microporous dispersion device has a micropore diameter of 30 μm to 50 μm and a temperature resistance ≥ 600℃.

[0015] Further, the pipeline carbon burning method for quantifying the deposited carbon mass on the inner wall of the reaction tube comprises:

[0016] Place the reaction tube after oxidation coking in a 800℃ tube furnace, pass pure oxygen to calcine, convert the coking on the inner wall of the reaction tube into carbon dioxide, then detect the carbon dioxide content by an infrared analyzer, and further convert into the deposited carbon mass.

[0017] Further, the rear-end filter is a sintered micron-level filter core.

[0018] Further, the filter core of the rear-end filter has a pore diameter of 2 μm to 4 μm.

[0019] Further, the collection and weighing of the suspended carbon particle mass by the rear-end filter comprises:

[0020] Place the rear-end filter in a 500 ml beaker, add anhydrous ethanol for ultrasonic cleaning, transfer the carbon particles into the solution, then transfer the carbon particles onto a 0.8 μm microporous filter membrane by a filter device, then place the microporous filter membrane into an 80℃ oven for drying for 2 h, collect the carbon particles and weigh.

[0021] The present application has the following beneficial effects:

[0022] The embodiment realizes the rapid intensification and precise quantification of the coking process by synergistically regulating the three key parameters of dissolved oxygen concentration, flow rate and reaction tube diameter. The fuel dissolved oxygen concentration is innovatively increased from the conventional 10 ppm to 40 ppm by using the bubble stone micropore dispersion technology, the flow rate is simultaneously reduced to 0.1 g / s, and the reaction tube diameter is expanded to 4.5 mm, thereby constructing a synergistic intensification system of high oxygen-low speed-large tube diameter. The design prolongs the fuel residence time, and realizes the coking amount reaching the conventional test level of 20 hours within 2-4 hours at an outlet oil temperature of 450-500 degrees Celsius. The accurate separation and weighing of the total coking amount are completed through the double coking quantification module (pipe carbonization + rear-end filter collection of suspended carbon particles), and the coke structure characterization (SEM) confirms that it is consistent with the actual working condition deposits. The invention solves the problems of long test period, small coking amount and large evaluation error of traditional coking test, and is suitable for rapid oxidation stability evaluation of aviation fuel, lubricating oil and other hydrocarbon fuels. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a flow chart of the multi-parameter synergistic intensification based carbon hydrocarbon fuel oxidation coking accelerated test method;

[0024] Figure 2 It is a schematic diagram of the comparison of oxygenated carbon amount under different tube diameters in the experiment;

[0025] Figure 3 It is a schematic diagram of the comparison of carbon amount under different flow rates in the experiment;

[0026] Figure 4 It is a schematic diagram of the comparison of carbon amount under different tube diameters in the experiment;

[0027] Figure 5 It is a schematic diagram of double carbon collection under the conditions of blank group and additive group in the experiment;

[0028] Figure 6 It is a SEM image of carbon deposition in the pipe in the conventional experiment (65h);

[0029] Figure 7 It is a SEM image of carbon deposition collected by the tail-end filter in the experiment. DETAILED DESCRIPTION

[0030] The specific embodiments of the present application are described below to facilitate the understanding of the present application by those skilled in the art, but it should be clear that the present application is not limited to the scope of the specific embodiments, and for those skilled in the art, it is obvious that all kinds of changes within the spirit and scope of the present application defined and determined by the appended claims are within the scope of protection.

[0031] EMBODIMENT

[0032] AsFigure 1 As shown, the embodiment of the present application provides a carbon hydrogen fuel oxidation coking accelerated test method based on multi-parameter synergistic reinforcement, which comprises the following steps S1 to S5:

[0033] S1, oxygen is introduced into the carbon hydrogen fuel through a microporous dispersion device to make the dissolved oxygen concentration in the fuel reach 30 ppm to 50 ppm;

[0034] In an optional embodiment of the present application, the microporous dispersion device used in step S1 is bubble stone. The micropore diameter of the microporous dispersion device is 30 μm to 50 μm, and the temperature resistance is ≥600℃.

[0035] This embodiment first carries out oxygenation pretreatment of the carbon hydrogen fuel. The aviation kerosene oxidation coking experimental device is composed of four parts of an oil supply system, a reaction system, a test analysis system and a cooling recovery system. An oxygenation pretreatment device is added in the oil supply system, the carbon hydrogen fuel required for the experiment is poured into the bubble stone dispersion device, and oxygen is introduced into the device. In the process of fuel experiment, the content of dissolved oxygen in the fuel needs to be monitored in real time. In this embodiment, the dissolved oxygen concentration in the fuel is measured by using a Mettler-Toledo InPro6850i polarographic oxygen sensor. The sensor uses an electrochemical method, and the accuracy is 1% ± 6ppb. When the oxygen concentration is stable at about 40 ppm, the experiment is prepared.

[0036] S2, pumping the oxygen-containing fuel into a reaction tube with an inner diameter of 4.5 mm to 5.0 mm at a flow rate of 0.08 g / s to 0.12 g / s;

[0037] In an optional embodiment of the present application, step S2 uses methylcyclohexane as the raw material, the mass flow rate is 0.1 g / s, a single-stage heating is adopted, and the oxidation coking test of the fuel is carried out. The reaction section is a 304 alloy tube with an inner diameter of 4.5 mm and a length of 800 mm, the outlet fuel temperature of the reaction section is controlled to be 500℃, the outlet pressure is 3.5 MPa, and the conversion rate, gas production rate and heat sink of methylcyclohexane during reaction are recorded.

[0038] S3, carrying out oxidation coking reaction under the conditions of an outlet oil temperature of the reaction tube of 450℃ to 500℃ and a pressure of 3.5 MPa;

[0039] In an optional embodiment of the present application, step S3 carries out the oxidation coking experiment of the carbon hydrogen fuel on a high-pressure oxidation coking experimental table, and the experimental time is between 2-4h.

[0040] S4, quantifying the mass of the carbon deposited on the inner wall of the reaction tube by using a pipeline carbon burning method;

[0041] In an optional embodiment of the present application, step S4 places the oxidized and coked reaction tube in a 800℃ tube furnace, and passes pure oxygen to calcine, so that the coke on the metal inner wall is converted into carbon dioxide, which is then detected by an infrared analyzer to convert into the mass of the deposited carbon.

[0042] S5, collecting and weighing the mass of the suspended carbon particles by the back-end filter.

[0043] In an optional embodiment of the present application, step S5 places the filter and filter core in a 500ml beaker, adds anhydrous ethanol for ultrasonic cleaning, transfers the carbon particles into the solution, and then transfers the carbon particles to a 0.8μm microporous filter membrane through a filtering device, and then places the microporous filter membrane in an 80℃ oven for drying for 2h, to collect and weigh the carbon particles.

[0044] This embodiment realizes the rapid intensification and precise quantification of the coking process by synergistically regulating the three key parameters of dissolved oxygen concentration, flow rate and reaction tube diameter. The fuel dissolved oxygen concentration is innovatively increased from the conventional 10ppm to 40ppm by using the bubble stone microporous dispersion technology, the flow rate is simultaneously reduced to 0.1g / s, and the reaction tube diameter is expanded to 4.5mm, to construct a synergistic intensification system of high oxygen-low speed-large tube diameter. This design prolongs the fuel residence time, and realizes the coking amount reaching the level of 20 hours of conventional testing within 2-4 hours at an outlet oil temperature of 450-500℃. The total coking amount is accurately separated and weighed by the double coking quantification module (pipe carbonization + back-end filter collecting suspended carbon particles), and the coke structure characterization (SEM) confirms that it is consistent with the actual working deposit. The present application solves the problems of long test period, small coking amount and large evaluation error of traditional coking test, and is suitable for rapid oxidation stability evaluation of aviation fuel, lubricating oil and other hydrocarbon fuels.

[0045] Comparative Example 1

[0046] According to the oxygenation pretreatment method of the hydrocarbon fuel in the above embodiment.

[0047] Methylcyclohexane was used as the raw material, the mass flow rate was 1g / s, 0.5g / s, 0.25g / s and 0.1g / s, and single-stage heating was adopted to perform the oxidation coking test of the fuel, wherein the reaction section was a 304 alloy tube with an inner diameter of 1mm and a length of 800mm, the outlet fuel temperature of the reaction section was controlled at 500℃, the outlet pressure was 3.5Mpa, the conversion rate, gas production rate and heat sink of methylcyclohexane during reaction were recorded, and the oxidation coking experiment of the hydrocarbon fuel was performed on a high-pressure oxidation coking experiment table, and the experimental time was 2h.

[0048] Comparative Example 2

[0049] According to the oxygenation pretreatment method of the hydrocarbon fuel in the above embodiment.

[0050] Using methylcyclohexane as the raw material, and with mass flow rates of 1 g / s, 0.5 g / s, 0.25 g / s, and 0.1 g / s, a single-stage heating system was used to conduct oxidative coking experiments on the fuel. The reaction section consisted of a 304 alloy tube with an inner diameter of 2 mm and a length of 800 mm. The outlet fuel temperature of the reaction section was controlled at 500 °C, and the outlet pressure was 3.5 MPa. The conversion rate, gas production rate, and heat sink rate of the methylcyclohexane reaction were recorded. The oxidative coking experiment on hydrocarbon fuels was conducted on a high-pressure oxidative coking experimental platform for 2 hours.

[0051] Compare with Example 3

[0052] The hydrocarbon fuel oxygenation pretreatment method described in the above embodiments shall be followed.

[0053] Using methylcyclohexane as the raw material, and with mass flow rates of 1 g / s, 0.5 g / s, 0.25 g / s, and 0.1 g / s, a single-stage heating system was used to conduct oxidative coking experiments on the fuel. The reaction section consisted of a 304 alloy tube with an inner diameter of 3 mm and a length of 800 mm. The outlet fuel temperature of the reaction section was controlled at 500 °C, and the outlet pressure was 3.5 MPa. The conversion rate, gas production rate, and heat sink rate of the methylcyclohexane reaction were recorded. The oxidative coking experiment on hydrocarbon fuels was conducted on a high-pressure oxidative coking experimental platform for 2 hours.

[0054] Compare with Example 4

[0055] The hydrocarbon fuel oxygenation pretreatment method described in the above embodiments shall be followed.

[0056] Using methylcyclohexane as the raw material, and with mass flow rates of 1 g / s, 0.5 g / s, 0.25 g / s, and 0.1 g / s, a single-stage heating system was used to conduct oxidative coking experiments on the fuel. The reaction section consisted of a 304 alloy tube with an inner diameter of 4.5 mm and a length of 800 mm. The outlet fuel temperature of the reaction section was controlled at 500 °C, and the outlet pressure at 3.5 MPa. The conversion rate, gas production rate, and heat sink rate of the methylcyclohexane reaction were recorded. The oxidative coking experiment on hydrocarbon fuels was conducted on a high-pressure oxidative coking test bench for 2 hours.

[0057] Compare with Example 5

[0058] The experiment was repeated while keeping all other operating conditions the same, without performing the oxygenation pretreatment as in Control Examples 1-4.

[0059] like Figures 2 to 7 As shown, Figure 5MCH represents methylcyclohexane, BHT represents butyl hydroxytoluene, Ph2Se2 represents diphenyl diselenide, THnone represents tetrahydronaphthalene, from the experiment of the embodiment and the control example of the application, it can be concluded that, when the fuel dissolved oxygen concentration is increased from the conventional 10 ppm to 40 ppm, the flow rate is simultaneously reduced to 0.1 g / s and the inner diameter of the reaction tube is expanded to 4.5 mm, under the synergistic strengthening system of high oxygen-low speed-large pipe diameter, the coking amount reaches the level of 20 hours of conventional test within 2-4 hours.

[0060] The application establishes the synergistic model of dissolved oxygen concentration (0.1-50 ppm), flow rate (0.08-0.12 g / s) and pipe diameter (4.0-5.0 mm), and the equivalent coking amount of 20 hours of conventional method is obtained within 2-4 hours at the outlet oil temperature of 450-500 DEG C, and the SEM analysis proves that the lamellar structure of coke body (2.3+ / -0.4 nm) is highly consistent with the actual working deposit (the similarity is greater than 92%); the precise separation of deposited carbon / suspended carbon is realized by the pipeline carbon burning method and the filter, and the technical blank of fuel additive evaluation is filled.

[0061] The application is described with reference to flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device that realizes the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks. Figure 1 The functions specified in one or more flows and / or blocks.

[0062] These computer program instructions can also be stored in a computer readable storage medium which can guide the computer or other programmable data processing device to work in a specific way, so that the instructions stored in the computer readable storage medium produce a product including instruction devices, which realize the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks. Figure 1 The functions specified in one or more flows and / or blocks.

[0063] These computer program instructions can also be loaded into the computer or other programmable data processing device, so that a series of operation steps are performed on the computer or other programmable device to produce a computer implemented process, so that the instructions executed on the computer or other programmable device provide a product for realizing the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks. Figure 1steps of the functions specified in the one or more blocks.

[0064] The principles and implementation manners of the present application are described in the embodiments. The above description of the embodiments is only used to help understand the method of the present application and its core idea. Meanwhile, for those skilled in the art, according to the idea of the present application, the specific implementation manners and application scopes can be changed. In summary, the content of the description should not be understood as a limitation of the present application.

[0065] Those skilled in the art will understand that the embodiments described herein are for the purpose of understanding the principles of the present application and should be understood as not limiting the scope of protection of the present application. Those skilled in the art can make various other specific modifications and combinations according to the technical inspiration disclosed in the present application without departing from the essence of the present application, and these modifications and combinations are still within the scope of protection of the present application.

Claims

1. A method for accelerated test of coking of hydrocarbon fuel oxidation based on multi-parameter synergistic reinforcement, characterized in that, The method comprises the following steps: Dissolve oxygen in the hydrocarbon fuel by a microporous dispersion device to reach a concentration of 30 ppm to 50 ppm; Pump the oxygen-containing fuel into a reaction tube with an inner diameter of 4.5 mm to 5.0 mm and a length of 80 cm at a flow rate of 0.08 g / s to 0.12 g / s; Perform the oxidation and coking reaction at an oil temperature of 450 ℃ to 500 ℃ and a pressure of 3.5 MPa at the outlet of the reaction tube; Quantify the mass of the deposited carbon on the inner wall of the reaction tube by the pipe carbon burning method; Collect and weigh the mass of the suspended carbon particles by a back-end filter.

2. The multi-parameter synergistic accelerated test method for coking of hydrocarbon fuel oxidation based on claim 1, wherein, The microporous dispersion device is a bubble stone.

3. The multi-parameter synergy accelerated oxidation coking test method for hydrocarbon fuels based on the synergistic reinforcement according to claim 1 or 2, characterized in that, The microporous dispersion device has a micropore diameter of 30 μm to 50 μm and a temperature resistance of ≥600 ℃.

4. The multi-parameter synergistic accelerated test method for coking of hydrocarbon fuel oxidation based on claim 1, wherein, The pipe carbon burning method for quantifying the mass of the deposited carbon on the inner wall of the reaction tube comprises: Place the reaction tube after the oxidation and coking in a tube furnace at 800 ℃, pass pure oxygen to calcine, convert the coking on the inner wall of the reaction tube into carbon dioxide, and then detect the content of the carbon dioxide by an infrared analyzer to convert the mass of the deposited carbon.

5. The multi-parameter synergistic accelerated test method for coking of hydrocarbon fuel oxidation based on claim 1, wherein, The back-end filter is a sintered micron-level filter core.

6. The multi-parameter synergy accelerated oxidation coking test method for hydrocarbon fuels according to claim 1 or 5, wherein, The filter core of the back-end filter has a pore diameter of 2 μm to 4 μm.

7. The multi-parameter synergistic accelerated test method for coking of hydrocarbon fuel oxidation based on claim 1, wherein, The collection and weighing of the mass of the suspended carbon particles by the back-end filter comprises: Place the back-end filter in a 500 ml beaker, add anhydrous ethanol for ultrasonic cleaning, transfer the carbon particles to the solution, transfer the carbon particles to a 0.8 μm microporous filter membrane by a filtering device, then place the microporous filter membrane in an 80 ℃ oven for drying for 2 h, collect the carbon particles, and weigh. The method comprises the following steps: Dissolve oxygen in the hydrocarbon fuel by a microporous dispersion device to reach a concentration of 30 ppm to 50 ppm; Pump the oxygen-containing fuel into a reaction tube with an inner diameter of 4.5 mm to 5.0 mm and a length of 80 cm at a flow rate of 0.08 g / s to 0.12 g / s; Perform the oxidation and coking reaction at an oil temperature of 450 ℃ to 500 ℃ and a pressure of 3.5 MPa at the outlet of the reaction tube; Quantify the mass of the deposited carbon on the inner wall of the reaction tube by the pipe carbon burning method; Collect and weigh the mass of the suspended carbon particles by a back-end filter. The microporous dispersion device is a bubble stone. The microporous dispersion device has a micropore diameter of 30 μm to 50 μm and a temperature resistance of ≥600 ℃. The pipe carbon burning method for quantifying the mass of the deposited carbon on the inner wall of the reaction tube comprises: Place the reaction tube after the oxidation and coking in a tube furnace at 800 ℃, pass pure oxygen to calcine, convert the coking on the inner wall of the reaction tube into carbon dioxide, and then detect the content of the carbon dioxide by an infrared analyzer to convert the mass of the deposited carbon. The back-end filter is a sintered micron-level filter core. The filter core of the back-end filter has a pore diameter of 2 μm to 4 μm. The collection and weighing of the mass of the suspended carbon particles by the back-end filter comprises: Place the back-end filter in a 500 ml beaker, add anhydrous ethanol for ultrasonic cleaning, transfer the carbon particles to the solution, transfer the carbon particles to a 0.8 μm microporous filter membrane by a filtering device, then place the microporous filter membrane in an 80 ℃ oven for drying for 2 h, collect the carbon particles, and weigh.

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