High-efficiency recovery device for aviation engine residual / waste heat based on fuel chemical heat sink

Abstract

The application discloses an aero-engine residual / waste heat high-efficiency recovery device based on fuel chemical heat sink, which comprises a high-temperature alloy inner tube and a high-temperature alloy outer tube with a diffuser section, the high-temperature alloy inner tube forms a heat supply channel, the outer side of the high-temperature alloy inner tube is provided with a plurality of heat exchange strengthening branch plates, the high-temperature alloy outer tube with the diffuser section and the high-temperature alloy inner tube form a reforming channel, the plurality of heat exchange strengthening branch plates are located in the reforming channel, a reforming inlet is formed at the front end of the reforming channel, and a reforming outlet is formed at the rear end of the reforming channel; a hot air inlet is formed at the front end of the high-temperature alloy inner tube, and a hot air outlet is formed at the rear end of the high-temperature alloy inner tube. The application can quickly design an optimized reformer structure with compact structure, high heat conduction performance, large specific surface area and good reforming performance on the basis of obtaining a heat supply condition, simultaneously obtains optimal reactant inlet parameters, finally improves hydrogen production under the same heat supply condition, reduces the energy consumption of unit hydrogen production rate, and thereby improves the conversion rate and the theoretical net power of the device.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aero-engine thermal management, and relates to an aero-engine residual / waste heat efficient recovery device based on a fuel chemical heat sink. BACKGROUND

[0002] At present, the energy utilization in China still has the main problems of low utilization efficiency, poor economic benefits and great pressure on the ecological environment. Energy saving, emission reduction, energy consumption reduction and improvement of energy comprehensive utilization rate are important contents of energy development strategy planning and are the fundamental way to solve the energy problem in China. In the research work of aero-engine, the exhaust gas temperature can be as high as 800-900 DEG C after leaving the combustion chamber of the engine. Therefore, the exhaust gas has high heat content, and up to 35% of fuel energy is brought into the environment, which not only wastes energy resources, but also increases carbon emissions. After power generation through the exhaust gas turbine, the tail gas still has a very high temperature, and this part of the waste heat has the possibility of being further utilized. From the perspective of heat recovery and utilization and reduction of greenhouse gas emissions, fuel cells have the significant advantages of high efficiency and cleanliness and are considered as a promising new energy technology.

[0003] Fuel cells use hydrogen as fuel, but the volumetric energy density of hydrogen is low, and there are problems in storage and transportation. In view of the high chemical heat sink of aviation kerosene itself in the aero-engine, the hydrogen carrying density of aviation kerosene as a hydrogen carrying medium is much higher than that of compressed hydrogen and liquid hydrogen. With the advent of high-efficiency and low-cost catalysts, aviation kerosene steam reforming to produce hydrogen has thus entered the sight of people. As a strong endothermic reaction, the aviation kerosene steam reforming reaction needs a large amount of heat provided by the external environment. The reaction system is limited by heat transfer, and the dynamic response is relatively slow. Therefore, it is hoped that the waste heat of the engine exhaust gas can be used to provide the reaction temperature for the reforming reaction, and the hydrogen produced by the reforming reaction can be introduced into the fuel cell to generate power, so as to ultimately improve the overall thermal efficiency of the system. The reforming reactor is a device for realizing the methanol steam reforming reaction to produce hydrogen. In order to effectively improve the methanol conversion rate, hydrogen yield and reduce the energy consumption of the device, the reforming reactor should generally have a higher specific surface area and a higher heat transfer efficiency, so that the heat provided by the external heat source can be fully utilized to realize the efficient reforming of methanol. Therefore, it is necessary to study the influencing factors of the reforming reactor, and through reasonable optimization design of the reforming device, it is tried to improve the efficiency of the methanol reforming reaction to produce hydrogen while reducing the energy consumption of the device as much as possible.

[0004] From the traditional research means, it can be seen that the optimization of the reactor is relatively mechanical. Whether simulation or experiment, only one parameter such as the type, number and layout of the ribs in the channel is considered for the optimization effect of the reactor, and there is a lack of in-depth research on the overall optimization of the reactor under different working conditions. SUMMARY

[0005] The main purpose of the present application is to provide an aircraft engine residual / waste heat efficient recovery device based on fuel chemical heat sink, the reactor's methanol conversion rate and theoretical net power are measured by experiment, and then the structure parameters and reactant import parameters of the optimal reforming and heat exchange performance are obtained by combining neural network prediction.

[0006] The novel sleeve type reforming hydrogen production reactor based on the diffuser and support plate structure can recover and comprehensively utilize the waste gas residual heat to the maximum extent through the reforming channel added with the diffuser section and support plate structure and the aviation kerosene steam reforming endothermic reaction according to different heat channel conditions, enriches the fuel cell energy supply mode, and improves the comprehensive efficiency of the engine.

[0007] The present application adopts the following technical scheme.

[0008] The aircraft engine residual / waste heat efficient recovery device based on fuel chemical heat sink is characterized in that the device is a sleeve type reforming hydrogen production reactor based on the diffuser and support plate structure, comprises a high-temperature alloy inner pipe and a high-temperature alloy outer pipe with a diffuser section, the high-temperature alloy inner pipe constitutes a heat supply channel, the outer side of the high-temperature alloy inner pipe is provided with a support plate for strengthening heat exchange, the high-temperature alloy outer pipe with a diffuser section and the high-temperature alloy inner pipe constitute a reforming channel, a plurality of support plates for strengthening heat exchange are located in the reforming channel, a reforming inlet is formed at the front end of the reforming channel, and a reforming outlet is formed at the rear end of the reforming channel; a hot air inlet is formed at the front end of the high-temperature alloy inner pipe, and a hot air outlet is formed at the rear end of the high-temperature alloy inner pipe.

[0009] Further, the superheated steam mixture of aviation kerosene and water enters the reforming channel from the reforming inlet, is in contact with a catalytic bed after being warmed up in a preheating section, and then flows out from the reforming outlet; hot air flows in from the hot air inlet, exchanges heat after being in contact with the wall surface of the reforming channel, and then flows out from the hot air outlet; the support plate for strengthening heat exchange conducts the heat of the received high-temperature waste gas to the inner and outer wall surfaces of the reforming channel to supply heat for the reforming reaction.

[0010] The support plates are distributed at equal intervals in the reforming channel, and the thickness is consistent with the thickness of the inner and outer wall surfaces of the high-temperature alloy inner pipe in the sleeve type reforming hydrogen production reactor.

[0011] The diameter of the high-temperature alloy inner pipe in the sleeve type reforming hydrogen production reactor is smaller than the diameter of the high-temperature alloy outer pipe with a diffuser section.

[0012] The reforming channel of the sleeve type reforming hydrogen production reactor is divided into three parts, namely, an inlet diffuser and preheating section, a middle catalytic bed, and a product diffusion section.

[0013] The aircraft engine residual / waste heat efficient recovery device based on fuel chemical heat sink is characterized in that the sleeve type reforming hydrogen production reactor based on the diffuser and support plate structure is used to realize the efficient recovery of the aircraft engine residual / waste heat and the efficient utilization of the aviation kerosene chemical heat sink, and the specific implementation is as follows.

[0014] 1) Hot air flows in from the hot air inlet, exchanges heat with the wall of the reforming channel, and then flows out from the hot air outlet (4); the heat exchange enhancement support plate arranged inside the reforming channel transfers the heat of the received high-temperature exhaust gas to the inner and outer walls of the reforming channel to provide heat for the reforming reaction;

[0015] 2) The reforming reaction occurs in the reforming channel. The superheated steam mixture of aviation kerosene and water enters the reforming channel from the reforming inlet, and after being heated in the preheating section, it contacts the catalyst bed and undergoes a reforming reaction, and then flows out from the reforming outlet.

[0016] On the basis of obtaining the heating conditions, the present invention constructs an agent model based on the database to quickly design an optimized reformer structure with compact structure, high thermal conductivity, large specific surface area and good reforming performance, and at the same time obtains the optimal reactant inlet parameters.

[0017] The hot air in the shell-and-tube reforming hydrogen production reactor is the high-temperature exhaust gas received from the engine exhaust. The hydrogen-rich gas generated after the reaction gas is reformed enters the hydrogen fuel cell after treatment, and the hydrogen fuel cell supplies power to power-consuming equipment.

[0018] The reforming performance of the double-tube reforming hydrogen production reactor is based on the mass fraction of aviation kerosene at the reforming inlet and outlet, combined with the formula:

[0019] (1)

[0020] The conversion rate was obtained to evaluate the reforming performance of the reactor, where represents the mass fraction of imported aviation kerosene, Indicates the mass fraction of exported aviation kerosene.

[0021] The overall performance index of the double-tube reforming hydrogen production reactor is calculated based on the inlet and outlet parameters of the reforming channel and the estimated net power of the fuel cell in combination with formulas (2)-(3). :

[0022] (2)

[0023] (3)

[0024] Among them, the theoretical battery power output The fuel cell efficiency is expected to be around 67 W, with a hydrogen production of around 375 sccm. The effective utilization rate of hydrogen production is 60%. 80%;

[0025] in, Additional pumping power for transporting products and reactants, 为In the MSR entrance area, For the velocity at the MSR entrance.

[0026] Optimization of reforming channel structure parameters is determined by the reforming entrance of the reforming channel The number of support plates in the reforming channel Optimization of flow parameters is determined by the mass flow of reactants at the entrance of the reforming channel ;

[0027] When constructing the agent model, BP neural network is used for regression problem processing, as shown in the following formula, the network topology relationship is established, and the establishment of BP neural network is realized,

[0028] (4)

[0029] Wherein, Conversion rate And the set of theoretical net power , The neural network prediction model of multi-objective optimization parameters.

[0030] The present application proposes an aviation engine waste / heat efficient recovery device based on fuel chemical heat sink, the purpose is to obtain the optimized reforming hydrogen reactor structure, a complete agent model is constructed for different heating conditions, which can adjust the reactant inlet parameters according to different heat conditions to realize the maximum utilization of waste heat, improve the conversion rate of the device and improve the theoretical net power of the reforming device.

[0031] Compared with the traditional waste heat recovery scheme, the outstanding advantages of the present application are:

[0032] 1. Reforming hydrogen by using engine exhaust waste heat, reducing waste heat waste; 2. The reforming rich gas can be used for engine inlet mixed combustion, improving the combustion performance of the engine, reducing the fuel consumption rate, and improving the emission; 3. The reforming gas can be used for hydrogen fuel cell for aircraft or ship auxiliary power supply, improving the energy comprehensive utilization efficiency of the device, and improving the energy efficiency index of operation; 4. The optimized reformer structure obtained in the present application has the advantages of compact structure, low hydrogen supply pressure, safe operation, etc., and can give the optimal input parameters according to the heat channel conditions to realize the maximum utilization of waste heat. DETAILED DESCRIPTION

[0033] Figure 1 It is a sleeve type reforming hydrogen reactor based on diffuser and support plate structure; wherein, (a) is an inlet end schematic view, (b) is an outlet end schematic view.

[0034] Figure 2 It is a cross-sectional view of the sleeve type reforming hydrogen reactor based on diffuser and support plate structure.

[0035] Figure 3 The multi-objective optimization algorithm described in the detailed description.

[0036] Figure 4 The performance index diagram of the sleeve type reforming hydrogen production reactor based on the diffuser and strut structure under different flow rates. DETAILED DESCRIPTION

[0037] The present application will be further described below with reference to the drawings. It should be noted that the present embodiment is based on the technical solution, and detailed implementation and specific operation process are given, but the protection scope of the present application is not limited to the present embodiment.

[0038] As Figure 1 shown, one embodiment: an aviation engine residual / waste heat efficient recovery device based on fuel chemical heat sink, the device is a sleeve type reforming hydrogen production reactor based on diffuser and strut structure, including high-temperature alloy inner tube 10, high-temperature alloy outer tube 20 with diffuser section, high-temperature alloy inner tube 10 constitutes a heat supply channel, the outer side of high-temperature alloy inner tube 10 is provided with a strut 3 for strengthening heat exchange, a plurality of struts 3 for strengthening heat exchange are arranged in the reforming channel, a reforming inlet 2 is formed at the front end of the reforming channel, and a reforming outlet 5 is formed at the rear end; a hot air inlet 1 is formed at the front end of the high-temperature alloy inner tube 10, and a hot air outlet 4 is formed at the rear end.

[0039] The superheated steam mixture of aviation kerosene and water enters the reforming channel from the reforming inlet, is heated after the preheating section, contacts the catalyst bed and occurs reforming reaction, and then flows out from the reforming outlet; hot air flows in from the hot air inlet, exchanges heat after contacting the wall surface of the reforming channel, and then flows out from the hot air outlet; the strut for strengthening heat exchange conducts the heat of the received high-temperature exhaust gas to the inner and outer wall surfaces of the reforming channel to supply heat for the reforming reaction.

[0040] According to the optimization requirement of the reforming hydrogen production reactor for strengthening heat exchange, the preheating section at the front end of the reactor is set as a diffuser section, and a strut is added in the reforming channel.

[0041] The struts 3 are distributed at equal intervals inside the reforming channel, and the thickness is consistent with the thickness of the inner and outer wall surfaces of the high-temperature alloy inner tube 10 in the sleeve type reforming hydrogen production reactor.

[0042] The diameter of the high-temperature alloy inner tube in the sleeve type reforming hydrogen production reactor is smaller than the diameter of the high-temperature alloy outer tube 20 with diffuser section.

[0043] The reforming channel of the sleeve type reforming hydrogen production reactor is divided into three parts: inlet diffuser and preheating zone, middle catalyst bed, and product diffusion zone.

[0044] The scheme hopes to obtain the optimal reformer structure with compact structure, high heat conduction performance, large specific surface area and good reforming performance based on the database construction agent model on the basis of obtaining the heat supply condition, and obtains the optimal reactant import parameters.

[0045] The aviation engine waste / heat high-efficiency recovery device based on fuel chemical heat sink realizes high-efficiency recovery of aviation engine waste / heat and high-efficiency utilization of aviation kerosene chemical heat sink through the sleeve type reforming hydrogen reactor based on the diffuser and the branch plate structure, and specifically as follows.

[0046] 1) Hot air flows into the hot air inlet 1, exchanges heat with the wall surface of the reforming channel, and then flows out from the hot air outlet 4; the reinforced heat exchange branch plate 3 arranged in the reforming channel conducts the heat of the received high-temperature exhaust gas to the inner and outer walls of the reforming channel to supply heat for the reforming reaction;

[0047] 2) The reforming reaction occurs in the reforming channel, and the superheated steam mixture of aviation kerosene and water enters the reforming channel from the reforming inlet 2, is heated in the preheating section, contacts the catalytic bed and occurs the reforming reaction, and then flows out from the reforming outlet 5.

[0048] The hot air in the reactor is high-temperature exhaust gas received from the engine exhaust, the hydrogen-rich gas produced after the reforming of the reaction gas enters the fuel cell after treatment, and the hydrogen fuel cell supplies power to the power-consuming equipment.

[0049] The reforming performance of the reactor can be calculated according to the mass fraction of aviation kerosene at the inlet and outlet of the reforming, and the formula is:

[0050] (1)

[0051] The conversion rate is obtained to evaluate the reforming performance of the reactor, wherein the mass fraction of the inlet aviation kerosene is the mass fraction of the outlet aviation kerosene is.

[0052] The overall performance index of the reactor can be calculated according to the inlet and outlet parameters of the reforming channel, and the estimated net power of the fuel cell is calculated by combining formula (2)-(3) :

[0053] (2)

[0054] (3)

[0055] The theoretical cell power output is about 67 W, the hydrogen production is about 375 sccm, the efficiency of the fuel cell is 60%, and the effective utilization rate of hydrogen production is 80%.

[0056] wherein, is the additional pumping power for transporting products and reactants, 为 is the area of the MSR inlet region, is the velocity at the MSR inlet.

[0057] As Figure 2 shown, the optimization of the reforming channel structure parameters is determined by the reforming inlet diffuser angle of the reforming channel , the number of support plates in the reforming channel . The optimization of the flow parameters is determined by the reactant mass flow rate at the inlet of the reforming channel .

[0058] As Figure 3 shown, the agent model uses a BP neural network to process the regression problem, establishes the network topology relationship, and realizes the establishment of the BP neural network.

[0059] (4)

[0060] wherein, is the conversion rate and the theoretical net power set, is the neural network prediction model of the multi-objective optimization parameter.

[0061] As Figure 4 shown, α is the methanol conversion rate, β is the theoretical net power of the device, other conditions remain unchanged, the reactant inlet flow rate is gradually increased from 0.7 g / s to 1.2 g / s, and CFD simulation calculation is performed. It can be seen that when the reactant inlet flow rate gradually increases, the reforming performance of the reactor gradually increases. The reactor after structure optimization shows better reforming performance under various boundary conditions.

[0062] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A highly efficient recovery device for residual / waste heat from an aircraft engine based on a fuel chemical heat sink, characterized by: The device is a shell-and-tube reforming hydrogen production reactor with a pressure-expanding and support plate structure, comprising a high-temperature alloy inner tube (10) and a high-temperature alloy outer tube (20) with a pressure-expanding section. The high-temperature alloy inner tube (10) forms a heat supply channel. A support plate (3) for enhancing heat exchange is provided on the outside of the high-temperature alloy inner tube (10). A reforming channel is formed between the high-temperature alloy outer tube (20) with the pressure-expanding section and the high-temperature alloy inner tube (10). A plurality of support plates (3) for enhancing heat exchange are arranged in the reforming channel. A reforming inlet (2) is formed at the front end of the reforming channel, and a reforming outlet (5) is formed at the rear end. A hot air inlet (1) is formed at the front end of the high-temperature alloy inner tube (10), and a hot air outlet (4) is formed at the rear end. The efficient recovery of aircraft engine waste heat and the efficient utilization of aviation kerosene chemical heat sink are achieved through a shell-and-tube reforming hydrogen production reactor based on a diffuser and support plate structure. The details are as follows: 1) Hot air flows in from the hot air inlet (1), exchanges heat with the wall of the reforming channel, and then flows out from the hot air outlet (4); the heat exchange enhancement support plate (3) arranged inside the reforming channel transfers the heat of the received high-temperature exhaust gas to the inner and outer walls of the reforming channel to provide heat for the reforming reaction; 2) The reforming reaction occurs in the reforming channel. The superheated steam mixture of aviation kerosene and water enters the reforming channel from the reforming inlet (2), and after being heated in the preheating section, it contacts the catalyst bed and undergoes a reforming reaction, and then flows out from the reforming outlet (5); The hot air in the shell-and-tube reforming hydrogen production reactor is the high-temperature exhaust gas received from the engine exhaust. The hydrogen-rich gas generated after the reaction gas is reformed enters the hydrogen fuel cell after treatment, and the hydrogen fuel cell supplies power to the power-consuming equipment. The reforming performance of the double-tube reforming hydrogen production reactor is based on the mass fraction of aviation kerosene at the reforming inlet and outlet, combined with the formula: The conversion rate was obtained to evaluate the reforming performance of the reactor, where represents the mass fraction of imported aviation kerosene, Indicates the mass fraction of exported aviation kerosene; The overall performance index of the double-tube reforming hydrogen production reactor is calculated based on the inlet and outlet parameters of the reforming channel and combined with formulas (2)-(3) to calculate the estimated net power W of the fuel cell. net : In P =ΔP×A ch ×u in (3) Among them, the theoretical battery power output W FC It is estimated to be about 67W, and the efficiency of the fuel cell η Cell The effective utilization rate of hydrogen production is 60%. 80%; Among them, W P A is the additional pumping power for transporting products and reactants. ch is the area at the entrance of the MSR, u in is the velocity at the MSR inlet, ΔP represents the inlet and outlet pressure difference of the double-tube reforming hydrogen production reactor, and MSR is the abbreviation of methanol steam reforming.

2. The highly efficient aircraft engine waste heat recovery device based on fuel chemical heat sink according to claim 1 is characterized by: A superheated steam mixture of aviation kerosene and water enters the reforming channel from the reforming inlet (2), contacts the catalyst bed after being heated in the preheating section, undergoes a reforming reaction, and then flows out from the reforming outlet (5); hot air flows in from the hot air inlet (1), contacts the wall of the reforming channel for heat exchange, and flows out from the hot air outlet (4); the heat exchange-enhancing support plate (3) transfers the heat of the received high-temperature exhaust gas to the inner and outer walls of the reforming channel to provide heat for the reforming reaction.

3. The high-efficiency recovery device for aircraft engine residual / waste heat based on fuel chemical heat sink according to claim 1 is characterized in that: The support plates (3) are distributed at equal intervals inside the reforming channel, and their thickness is consistent with the thickness of the inner and outer walls of the high-temperature alloy inner tube (10) in the shell-and-tube reforming hydrogen production reactor.

4. The highly efficient aircraft engine waste heat recovery device based on fuel chemical heat sink according to claim 1 is characterized in that: The diameter of the high-temperature alloy inner tube in the shell-and-tube reforming hydrogen production reactor is smaller than the diameter of the aluminum alloy outer tube.

5. The high-efficiency recovery device for aircraft engine residual / waste heat based on fuel chemical heat sink according to claim 1 is characterized in that: The reforming channel of the shell-and-tube reforming hydrogen production reactor is divided into three parts: the inlet pressure diffusion and preheating zone, the middle catalytic bed, and the product diffusion zone.

6. The highly efficient aircraft engine waste heat recovery device based on fuel chemical heat sink according to claim 1 is characterized by: The optimized structural parameters of the reforming channel are determined by the reforming inlet diffuser angle θ and the number of support plates x in the reforming channel; the optimized flow parameters are determined by the reactant mass flow rate m at the reforming channel inlet. When constructing the agent model, BP neural network is used to process the regression problem. As shown in the following formula, the network topology relationship is established to realize the establishment of BP neural network. S p (X,W)=S net (θ,x,m) (4) Among them, S p is the combination of conversion rate X and theoretical net power W, S net Neural network prediction models with parameter optimization for multiple objectives.

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