An improved naphthenic hydrocarbon fuel and method of low pressure combustion promotion thereof

Abstract

The application provides an improved naphthene hydrocarbon fuel and a low-pressure combustion promoting method thereof, in particular, methylcyclohexane is used as a base fuel, and diethylsilane is added to methylcyclohexane to regulate the ignition temperature and ignition delay time of methylcyclohexane at low pressure. The modified naphthene hydrocarbon fuel obtained by the method has the advantages of stable physical form, no stratification, high heat value, good stability when the fuel is in contact with air at normal temperature and the like, the low-pressure combustion characteristics of the naphthene hydrocarbon fuel are regulated through directional regulation of the combustion base element reaction of the naphthene hydrocarbon fuel, the operation is simple, and the practicability is strong. The application solves the problem of low-pressure regulation difficulty of the hydrocarbon fuel, provides a solution for the low-pressure characteristic regulation of the naphthene hydrocarbon fuel, and provides technical reserves for reliable ignition of advanced aero-engine under low-pressure harsh working conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engine fuel combustion, and particularly to an improved naphthene hydrocarbon fuel and a low-pressure combustion promotion method thereof. BACKGROUND

[0002] In the development of advanced aero-engines, the great difference in the combustion flow field compared with the ground environment makes it very difficult for hydrocarbon fuels to reliably restart in high-altitude environments. The high-altitude relighting reliability of an aircraft is one of the important indicators of the advancement of aero-engines, but in the low-pressure environment at the cruising altitude of an aircraft, the combustion performance of aviation kerosene deteriorates sharply, and even reliable ignition cannot be achieved. In view of the difficulty of high-altitude ignition, some solutions have been proposed from the perspective of engine structure, such as designing different vortex structures to achieve better fuel / air mixing effect, but this inevitably leads to some loss of thrust performance.

[0003] In China, RP-3 is the most widely used aviation fuel, and the representative components include 52% of straight-chain alkanes and 40% of naphthenes. For naphthenes, through sensitivity analysis, the ten reactions of the fuel most sensitive to reaction parameters at different pressures are obtained, and it is found that the reaction type and reaction rate of the ten reactions with the highest sensitivity coefficient at different pressures show the trend that the higher the pressure, the easier the dehydrogenation reaction is to achieve, and the faster the reaction rate. In general, methylcyclohexane has stronger reactivity at high pressure. How to improve the low-pressure combustion performance of methylcyclohexane and other base hydrocarbon fuels in a low-pressure environment is a technical problem that needs to be solved urgently. SUMMARY

[0004] The purpose of the present application is to provide an improved naphthene hydrocarbon fuel and a low-pressure combustion promotion method thereof to solve the problem of difficult low-pressure regulation of hydrocarbon fuels and provide a solution for the low-pressure characteristic regulation of naphthene hydrocarbon fuels, which provides technical reserves for solving the reliable ignition of advanced aero-engines under low-pressure harsh working conditions.

[0005] The purpose of the present application is achieved by the following technical solutions:

[0006] An improved naphthene hydrocarbon fuel, comprising a base hydrocarbon fuel and an activation additive.

[0007] As a further technical solution, the base hydrocarbon fuel is methylcyclohexane.

[0008] As a further technical solution, the activation additive is diethylsilane.

[0009] The method comprises the following steps: adding methylcyclohexane as a base hydrocarbon fuel into a fuel tank under nitrogen protection; adding diethylsilane as an activation additive into the fuel tank under nitrogen protection; and uniformly mixing the base hydrocarbon fuel and the activation additive in the fuel tank by magnetic stirring.

[0010] As a further technical solution, the volume fraction of the base hydrocarbon fuel is 80%-95%, and the volume fraction of the activation additive is 5-20%.

[0011] As a further technical solution, the volume fraction of the base hydrocarbon fuel is 80%, and the volume fraction of the activation additive is 20%.

[0012] As a further technical solution, the volume fraction of the base hydrocarbon fuel is 85%, and the volume fraction of the activation additive is 15%.

[0013] As a further technical solution, the volume fraction of the base hydrocarbon fuel is 90%, and the volume fraction of the activation additive is 10%.

[0014] As a further technical solution, the volume fraction of the base hydrocarbon fuel is 95%, and the volume fraction of the activation additive is 5%.

[0015] A method for improving low-pressure combustion of a naphthene hydrocarbon fuel, which comprises the following steps:

[0016] (1) adding a base hydrocarbon fuel into a fuel tank under nitrogen protection;

[0017] (2) adding an activation additive into the fuel tank in which the base hydrocarbon fuel is added;

[0018] (3) uniformly mixing the liquid in the fuel tank by magnetic stirring.

[0019] According to the corresponding mixing ratio, the base fuel and the additive are respectively taken and uniformly mixed under inert gas protection, so that a modified liquid naphthene hydrocarbon fuel with low-pressure stable combustion characteristics can be obtained.

[0020] As a further technical solution, the method comprises the following steps:

[0021] (1) adding methylcyclohexane fuel into a fuel tank under nitrogen protection, and the volume percentage content is 80%-95%;

[0022] (2) adding diethylsilane into the fuel tank in which the methylcyclohexane fuel is added, and the volume percentage content is 5-20%;

[0023] (3) The liquid in the fuel tank is uniformly mixed by magnetic stirring.

[0024] Compared with the prior art, the present application has the following advantages:

[0025] 1. The modified naphthene hydrocarbon fuel obtained by the method has the advantages of stable physical form, no stratification, high heat value, good stability when in contact with air at room temperature, etc. The low-pressure combustion characteristics of the naphthene hydrocarbon fuel are adjusted by directional regulation of the combustion element reaction of the naphthene hydrocarbon fuel, which is simple to operate and has strong practicality.

[0026] 2. The present application proposes to modify the naphthene hydrocarbon fuel by adding a low-pressure combustion modifier to promote reliable ignition and stable combustion under low-pressure conditions. The selected additive can be dissolved in liquid multi-component hydrocarbon fuel and can effectively adjust the low-pressure ignition temperature and ignition delay time of the naphthene hydrocarbon fuel. The prepared modified fuel has the advantages of stable form, no stratification, good stability when in contact with air at room temperature, etc. The preparation process has the characteristics of simple operation and strong practicality. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is the low-pressure flammability limit of methylcyclohexane and a composite fuel containing 20% diethylsilane; x represents failed ignition, and o represents successful ignition.

[0028] Figure 2 is the ignition delay time of methylcyclohexane and a composite fuel containing 20% diethylsilane. DETAILED DESCRIPTION

[0029] The present application will be described in detail below in conjunction with the drawings and specific examples.

[0030] Example 1

[0031] The present application provides an improved naphthene hydrocarbon fuel and a method for promoting low-pressure combustion thereof. The method adjusts the low-speed dealkylation reaction under low pressure to a fast dehydrogenation reaction to improve the low-pressure combustion performance of methylcyclohexane. The modified naphthene hydrocarbon fuel is a mixed fuel of methylcyclohexane and diethylsilane. Specifically, diethylsilane is added to methylcyclohexane as a base fuel to regulate the ignition temperature and ignition delay time of methylcyclohexane under low pressure. The mechanism of regulating the low-pressure ignition characteristics of methylcyclohexane is to increase the concentration of HO2 free radicals under low-pressure conditions by fuel design, promote the dehydrogenation reaction of methylcyclohexane, and compete with the existing low-pressure rate reaction dealkylation reaction, thereby improving the low-pressure reactivity of methylcyclohexane.

[0032] The composite fuel is configured in the following proportions in this example:

[0033] Step one, add methylcyclohexane fuel into the fuel tank with nitrogen protection, the volume percentage is 95%;

[0034] Step two, add diethylsilane into the fuel tank with methylcyclohexane fuel, the volume percentage is 5%;

[0035] Step three, mix the liquid in the fuel tank uniformly by magnetic stirring.

[0036] This embodiment uses low-pressure constant temperature platform experimental device to measure the ignition characteristics of ethyl methylcyclohexane and modified naphthenic hydrocarbon fuel containing 5% diethylsilane on the low-pressure constant temperature platform experimental device to illustrate the effect of the additive on the low-pressure ignition characteristic regulation of methylcyclohexane.

[0037] Example 2

[0038] The present application provides an improved naphthenic hydrocarbon fuel and a low-pressure combustion promoting method thereof, wherein the modified naphthenic hydrocarbon fuel is a mixed fuel of methylcyclohexane and diethylsilane.

[0039] In this embodiment, the composite fuel is configured in the following proportions:

[0040] Step one, add methylcyclohexane fuel into the fuel tank with nitrogen protection, the volume percentage is 90%;

[0041] Step two, add diethylsilane into the fuel tank with methylcyclohexane fuel, the volume percentage is 10%;

[0042] Step three, mix the liquid in the fuel tank uniformly by magnetic stirring.

[0043] This embodiment uses low-pressure constant temperature platform experimental device to measure the ignition characteristics of ethyl methylcyclohexane and modified naphthenic hydrocarbon fuel containing 10% diethylsilane on the low-pressure constant temperature platform experimental device to illustrate the effect of the additive on the low-pressure ignition characteristic regulation of methylcyclohexane.

[0044] Example 3

[0045] The present application provides an improved naphthenic hydrocarbon fuel and a low-pressure combustion promoting method thereof, wherein the modified naphthenic hydrocarbon fuel is a mixed fuel of methylcyclohexane and diethylsilane.

[0046] In this embodiment, the composite fuel is configured in the following proportions:

[0047] Step one, add methylcyclohexane fuel into the fuel tank with nitrogen protection, the volume percentage is 85%;

[0048] Step two, add diethylsilane into the fuel tank with methylcyclohexane fuel, the volume percentage is 15%;

[0049] Step three, the liquid in the fuel tank is uniformly mixed by magnetic stirring method.

[0050] This embodiment uses a low-pressure constant temperature platform experimental device to measure the ignition characteristics of ethyl methylcyclohexane and modified naphthenic hydrocarbon fuel containing 15% diethylsilane on the low-pressure constant temperature platform experimental device to illustrate the effect of the additive on the low-pressure ignition characteristics of methylcyclohexane.

[0051] Example 4

[0052] The present application provides an improved naphthenic hydrocarbon fuel and a method for promoting low-pressure combustion thereof, wherein the modified naphthenic hydrocarbon fuel is a mixture of methylcyclohexane and diethylsilane.

[0053] In this embodiment, the composite fuel is configured in the following proportions:

[0054] Step one, methylcyclohexane fuel is added to a fuel tank under nitrogen protection, with a volume percentage of 80%;

[0055] Step two, diethylsilane is added to the fuel tank with methylcyclohexane fuel, with a volume percentage of 20%;

[0056] Step three, the liquid in the fuel tank is uniformly mixed by magnetic stirring method.

[0057] This embodiment uses a low-pressure constant temperature platform experimental device to measure the ignition characteristics of ethyl methylcyclohexane and modified naphthenic hydrocarbon fuel containing 20% diethylsilane on the low-pressure constant temperature platform experimental device to illustrate the effect of the additive on the low-pressure ignition characteristics of methylcyclohexane.

[0058] As shown in Figure 1 , the technical effect of this embodiment is that compared with methylcyclohexane, the low-pressure ignition range is widened from 0.8-1.0 atm to 0.3-1.0 atm at a temperature of 923K, and the low-pressure ignition performance of the composite hydrocarbon fuel is effectively improved. At the same time, compared with methylcyclohexane at 923K, the modified composite hydrocarbon fuel at a temperature of 723K, the low-pressure ignition range is widened from 0.8-1.0 atm to 0.4-1.0 atm, and the low-temperature ignition performance and low-pressure ignition performance of the composite hydrocarbon fuel are effectively improved.

[0059] As shown in Figure 2As shown, the technical effect of the present embodiment is that the ignition delay time of 20% diethylsilane / methylcyclohexane is significantly reduced. Compared with pure methylcyclohexane at a temperature of 923K and 0.7atm, the ignition delay time of 20% diethylsilane / methylcyclohexane is reduced from 1240ms to 56ms. And for 20% diethylsilane / methylcyclohexane at a temperature of 923K, when the pressure is from 0.3-1.0atm, the low-pressure ignition delay time is effectively reduced, showing a relatively stable low-pressure combustion characteristic. In addition, compared with pure methylcyclohexane at a temperature of 923K and 0.8atm, the ignition delay time of 20% diethylsilane / methylcyclohexane at a temperature of 723K and 0.8atm is 413ms. And when the pressure is from 0.3-1.0atm, the low-pressure ignition delay time also shows a stable low-pressure combustion characteristic.

[0060] The above use of diethylsilane to regulate the low-pressure combustion characteristics of liquid naphthenic hydrocarbon fuel is original, has never been disclosed, and its working manner is different from any existing literature, which is the regulation of the low-pressure combustion characteristics of methylcyclohexane promoted by diethylsilane.

[0061] The technical details of the above-mentioned regulation of the low-pressure combustion characteristics of methylcyclohexane promoted by diethylsilane are as follows: 1. Adding diethylsilane increases the concentration of HO2 free radicals under low-pressure conditions; 2. Promoting the dehydrogenation reaction of methylcyclohexane in the combustion reaction, competing with the existing low-pressure deceleration reaction dealkylation reaction, thereby improving the low-pressure reactivity of methylcyclohexane. The addition of diethylsilane can significantly improve the regulation of the low-pressure combustion performance of methylcyclohexane.

[0062] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. It should be noted that any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for improving low pressure combustion of naphthenic hydrocarbon fuels, characterized by, The method comprises: (1) adding methylcyclohexane fuel into a fuel tank under nitrogen protection; (2) adding diethylsilane into the fuel tank with methylcyclohexane fuel added above; the volume percentage of the added methylcyclohexane fuel in the total volume of methylcyclohexane fuel and diethylsilane is 80-95%, and the volume percentage of the added diethylsilane in the total volume of methylcyclohexane fuel and diethylsilane is 5-20%; (3) uniformly mixing the liquid in the fuel tank by magnetic stirring.

2. The method of improving low pressure combustion of naphthenic hydrocarbon fuels of claim 1, wherein, The volume percentage of the methylcyclohexane fuel is 80%, and the volume percentage of the diethylsilane is 20%.

3. The method of improving low pressure combustion of naphthenic hydrocarbon fuels of claim 1, wherein, The volume percentage of the methylcyclohexane fuel is 85%, and the volume percentage of the diethylsilane is 15%.

4. The method of improving low pressure combustion of naphthenic hydrocarbon fuels of claim 1, wherein, The volume percentage of the methylcyclohexane fuel is 90%, and the volume percentage of the diethylsilane is 10%.

5. The method of improving low pressure combustion of naphthenic hydrocarbon fuels of claim 1, wherein, The volume percentage of the methylcyclohexane fuel is 95%, and the volume percentage of the diethylsilane is 5%.

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