CN113351144B

CN113351144B - Fuel catalytic reformer based on waste heat utilization

Info

Publication number: CN113351144B
Application number: CN202110609678.XA
Authority: CN
Inventors: 兰健; 周超; 郭岍桢; 吕田; 顾根香; 韩东
Original assignee: Shanghai Jiaotong University; Shanghai MicroPowers Co Ltd
Current assignee: Shanghai Jiaotong University; Shanghai MicroPowers Co Ltd
Priority date: 2021-06-01
Filing date: 2021-06-01
Publication date: 2022-10-18
Anticipated expiration: 2041-06-01
Also published as: CN113351144A

Abstract

The invention provides a fuel catalytic reformer based on waste heat utilization, which comprises a heat exchange evaporator, a swirler, a mixing chamber, a collecting tank, a catalytic reaction chamber and a shell, wherein the heat exchange evaporator comprises a first flow passage and a second flow passage; the cyclone, the mixing chamber and the catalytic reaction chamber are sequentially connected with one another from top to bottom in the shell, a first accommodating space is formed between the outer walls of the cyclone, the mixing chamber and the catalytic reaction chamber and the shell, and high-temperature waste gas enters the first accommodating space through the high-temperature waste gas inlet, enters the top of the first flow channel through the medium-temperature waste gas connecting port and is discharged from the bottom of the first flow channel through the low-temperature waste gas outlet; liquid water enters the bottom of the second flow channel through the liquid water inlet, enters the cyclone, the mixing chamber and the catalytic reaction chamber from the top of the second flow channel and is discharged from the reformed gas outlet.

Description

Fuel catalytic reformer based on waste heat utilization

Technical Field

The invention relates to the technical field of catalytic reforming of fuels, in particular to a catalytic reformer of a fuel based on waste heat utilization.

Background

The engine has higher exhaust gas temperature and meets the temperature requirement of catalytic reforming of fuel, so that the heat energy required by catalytic reforming can be provided by utilizing the waste heat of high-temperature exhaust gas. The catalytic reforming of fuel mainly includes steam reforming, partial oxidation reforming, autothermal reforming, and the like. Oxygen introduced by partial oxidation reforming and autothermal reforming is an important factor in fuel coking. And the waste heat of the waste gas is used for supplying heat, so that the fuel and the steam are subjected to catalytic reforming reaction to form high-temperature hydrogen-rich reformed gas, and then the high-temperature hydrogen-rich reformed gas is injected into the combustion chamber again for combustion, or the high-temperature hydrogen-rich reformed gas is used for a technical means of converting the fuel into electric energy in a fuel cell.

The fuel catalytic reformer based on waste heat utilization can generate high-temperature hydrogen-rich pyrolysis gas by utilizing waste heat under the conditions of not changing a basic combustion system and not providing an additional heat supply device. However, the existing reforming equipment has low heat exchange efficiency, so that the energy utilization efficiency is low, the size is large, and the phenomena of carbon deposition, coking and the like are usually accompanied.

Patent document CN1887691A discloses a methanol catalytic reforming hydrogen production device using waste heat of an internal combustion engine and a control method thereof, belonging to the field of application of waste heat of the internal combustion engine. The device mainly comprises a methanol aqueous solution gasification cavity (17), a catalytic reaction cavity (16) and a reformed gas product cavity (15) which are arranged at the front part, the middle part and the rear part of a reformer shell (5). The middle part of the reformer shell (5) is provided with porous honeycomb ceramics (8), the inside of the porous honeycomb ceramics (8) is provided with a catalytic reaction cavity (16), the inner wall of the catalytic reaction cavity (16) is provided with honeycomb-shaped small holes, reforming catalysts are coated on the inner walls of the small holes, and the heat exchange tubes (7) axially penetrate through the porous honeycomb ceramics (8).

Disclosure of Invention

In view of the shortcomings of the prior art, it is an object of the present invention to provide a catalytic reformer for fuel based on waste heat utilization.

The invention provides a fuel catalytic reformer based on waste heat utilization, which comprises a heat exchange evaporator, a swirler, a mixing chamber, a collecting tank, a catalytic reaction chamber and a shell, wherein the heat exchange evaporator is arranged in the shell;

the heat exchange evaporator comprises a first flow passage and a second flow passage;

the cyclone, the mixing chamber and the catalytic reaction chamber are sequentially connected with one another from top to bottom in the shell, and a first accommodating space is formed between the outer walls of the cyclone, the mixing chamber and the catalytic reaction chamber and the shell;

high-temperature waste gas enters the bottom of the first accommodating space through the high-temperature waste gas inlet, flows to the top of the first accommodating space, is changed into medium-temperature waste gas, enters the top of the first flow channel through the medium-temperature waste gas connecting port, and is discharged from the bottom of the first flow channel through the low-temperature waste gas outlet;

liquid water enters the bottom of the second flow channel through a liquid water inlet, enters the cyclone, the mixing chamber and the catalytic reaction chamber from the top of the second flow channel, and is discharged from a reformed gas outlet, and the mixing chamber is connected with a fuel inlet;

the medium-temperature waste gas in the first flow channel and the liquid water in the second flow channel perform heat transfer in a countercurrent mode so that the medium-temperature waste gas is changed into low-temperature waste gas, and the liquid water is changed into water vapor.

Preferably, the heat exchange evaporator adopts a shell-and-tube heat exchange structure, wherein the first flow channel is a shell pass, the second flow channel is a tube pass, and the number of the second flow channels is one or more.

Preferably, the second flow passage extends circumferentially with a plurality of ribs.

Preferably, the fuel inlet injects fuel into the mixing chamber through a pressure swirl atomizing nozzle.

Preferably, the pressure swirl atomizing nozzle sprays fuel into the mixing chamber as atomized droplets of 10-30 μm in diameter.

Preferably, the cyclone adopts any one of the following structures:

-the swirl outlet is a plurality of outlet pipes which are uniformly or non-uniformly arranged in a clockwise or counterclockwise tangential manner;

the steam-water separator comprises a swirl outlet header pipe and a fixed shaft, wherein a plurality of rotary blades are sequentially and uniformly arranged between the swirl outlet header pipe and the fixed shaft, a swirl channel is formed between every two adjacent rotary blades, and the steam forms a rotary air flow through the swirl channel.

Preferably, a high-boiling-point residual collecting tank is arranged on the mixing chamber.

Preferably, a chamber space arrangement is formed from the mixing chamber to the interior of the catalytic reaction chamber from the expansion section to the contraction section and then to the expansion section.

Preferably, a turbulence column is arranged on the contraction section.

Preferably, the heat exchanging evaporators are arranged in a circumferential direction of the casing.

Compared with the prior art, the invention has the following beneficial effects:

1. the invention carries out reforming by utilizing waste heat of waste gas, has high heat exchange efficiency, increases the heat value of the reformed gas, and can inhibit the generation of carbon deposition coking phenomenon by the steam reforming mode compared with other reforming modes.

2. The invention is integrated into an integral cylindrical reformer through the design layout, thereby leading the integral structure to be compact and integrated and occupying small space.

3. The evaporator of the invention fully utilizes the heat exchange area of the outer layer to generate water vapor, and the heat exchange of the inner layer is strengthened, so that the heat loss is small, the heat exchange efficiency is improved, and the waste heat of waste gas is more fully utilized.

4. According to the cyclone, the scheme of forming cyclone tangentially is utilized, so that the steam is more fully contacted with the fuel, the effects of convective heat transfer and evaporation mixing are enhanced, high boiling point residues are separated, and the evaporation residues are prevented from accumulating on the surface of a catalyst and influencing a subsequent reforming reaction module.

5. The invention adopts the pressure swirl atomizing nozzle, and forms tiny liquid drops by utilizing the pressure swirl atomizing principle, thereby strengthening the fuel evaporation effect.

6. The invention adopts the expansion-contraction-expansion mixing chamber, changes the flow state through the size design of the flow channel, strengthens turbulence and vortex, and leads the flow mixing to be more sufficient and uniform.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of a preferred embodiment of a swirler;

fig. 3 is a schematic structural view of a swirler in a variation.

The figures show that:

medium-temperature waste gas connector 11 of liquid water inlet 1

Low temperature waste gas outlet 12 of heat exchange evaporator 2

Cyclone 3 casing 13

First accommodation space 14 of fuel inlet 4

First flow passage 15 of pressure swirl atomizing nozzle 5

Second flow passage 16 of mixing chamber 6

Cyclone outlet 17 of collecting tank 7

Catalytic reaction chamber 8 swirl outlet manifold 18

Reformed gas outlet 9 fixed shaft 19

High temperature waste gas inlet 10 rotating blade 20

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.

The invention provides a fuel catalytic reformer based on waste heat utilization, which comprises a heat exchange evaporator 2, a cyclone 3, a mixing chamber 6, a collecting tank 7, a catalytic reaction chamber 8 and a shell 13 as shown in figure 1, wherein the heat exchange evaporator 2 comprises a first flow passage 15 and a second flow passage 16, the cyclone 3, the mixing chamber 6 and the catalytic reaction chamber 8 which are sequentially connected are sequentially arranged in the shell 13 from top to bottom, and a first accommodating space 14 is formed between the outer walls of the cyclone 3, the mixing chamber 6 and the catalytic reaction chamber 8 and the shell 13. The heat exchanging evaporator 2 is arranged along the circumferential direction of the case 13 so that the heat absorbing efficiency is higher.

Further, the high-temperature exhaust gas enters the bottom of the first accommodating space 14 through the high-temperature exhaust gas inlet 10, flows to the top of the first accommodating space 14, becomes medium-temperature exhaust gas, enters the top of the first flow channel 15 through the medium-temperature exhaust gas connecting port 11, and is discharged from the bottom of the first flow channel 15 through the low-temperature exhaust gas outlet 12. Liquid water enters the bottom of the second flow channel 16 through the liquid water inlet 1 and is discharged from the reformed gas outlet 9 after entering the swirler 3, the mixing chamber 6 and the catalytic reaction chamber 8 from the top of the second flow channel 16, the fuel inlet 4 is connected to the mixing chamber 6, the fuel inlet 4 injects fuel into the mixing chamber 6 through the pressure swirl atomizing nozzle 5, and the pressure swirl atomizing nozzle 5 preferably atomizes the fuel into droplets with the diameter of 10-30 μm and injects the droplets into the mixing chamber 6. The medium temperature exhaust gas in the first flow channel 15 and the liquid water in the second flow channel 16 perform heat transfer in a counter-flow manner, so that the medium temperature exhaust gas is changed into low temperature exhaust gas, and the liquid water is changed into water vapor.

Specifically, the heat exchange evaporator 2 adopts a shell-and-tube heat exchange structure, wherein the first flow channel 15 is a shell pass, the second flow channel 16 is a tube pass, and the number of the second flow channels 16 is one or more. In a preferred embodiment, the number of the second flow channels 16 is multiple, and the second flow channels 16 extend from multiple stages of fins along the circumferential direction.

The outlet of the heat exchange evaporator 2 is connected with the inlet of the cyclone 3, the outlet of the cyclone 3 is the mixed gas, and the fuel is sprayed into the mixing chamber by a cyclone atomization method. When the heat exchanger works, high-temperature waste gas is firstly introduced, water vapor and the waste gas exchange heat and evaporate in the heat exchange evaporator 2 to generate high-temperature water vapor, and then the high-temperature water vapor enters the mixing chamber through the swirler 3; the fuel is atomized by the nozzle and then sprayed into the high-temperature steam, and the fuel and the high-temperature steam exchange heat with each other and are fully mixed. The mixed gas enters a catalytic zone to react to generate reformed mixed gas.

The fuel catalytic reformer preferably adopts a cylindrical device as a whole, and adopts a layered design to enable the structure to be compact and integrated. The heat exchange evaporator 2, the cyclone 3 and the mixing chamber 6 can be connected with different chambers through connecting pipelines in sequence.

Specifically, the heat exchange evaporator 2 converts water introduced into an evaporation chamber into high-temperature steam by using a shell-and-tube heat exchange mode; and discharging the medium-temperature waste gas after cooling. The heat exchange evaporator 2 is positioned at the outermost layer and wraps the cyclone 3 and the mixing chamber 6, and meanwhile, the heat exchange efficiency can be improved by utilizing a heat exchange enhancement method.

Specifically, the swirler 3 can convert high-temperature water vapor into swirling air to enter the mixing chamber, the existence of the swirling air enables evaporation and mixing to be more uniform, and meanwhile centrifugal force generated by the swirling air can separate non-evaporated high-boiling-point residues in the fuel. The swirler 3 is located the inlayer upper end, and the accessible changes whirl intensity and improves the evaporation mixing effect.

The pressure cyclone atomizing nozzle 5 atomizes the fuel into small liquid drops, so that the fuel can absorb heat and evaporate quickly, and the contact overheating is avoided, and carbon deposition coking is caused. Pressure whirl atomizing nozzle 5 is located 3 exports of swirler, and mixing chamber 6 entrances, and the direction of spraying points to mixing chamber 6 along the axis, and multiple modes such as accessible regulation injection pressure and injection angle improve the mixing effect simultaneously.

The fuel in the mixing chamber 6 is atomized and then directly sprayed into high-temperature steam for evaporation, and is fully mixed with swirling water vapor along the chamber to form mixed gas. The mixer is centrosymmetric about the central axis, and the chamber is designed along the flow direction to change the flow state, thereby improving the mixing effect and flow distribution.

The evaporation and mixing processes are all carried out at high temperature and high pressure, the fuel is liquid fuel, and the main energy is completed by utilizing the waste heat of the exhaust gas of the engine.

In particular, said cyclone 3 can adopt various structures, in a preferred example, as shown in fig. 2, the cyclone 3 adopts a plurality of outlet pipes which are uniformly or non-uniformly arranged along clockwise or counterclockwise tangential direction as the cyclone outlet 17; in a variation, the cyclone 3 includes a cyclone outlet manifold 18 and a fixed shaft 19, a plurality of rotating blades 20 are sequentially and uniformly arranged between the cyclone outlet manifold 18 and the fixed shaft 19, a cyclone passage is formed between two adjacent rotating blades 20, and the water vapor forms a rotating air flow through the cyclone passage.

In the invention, in order to improve the mixing effect, a cavity space arrangement from the expansion section to the contraction section and then to the expansion section is formed from the mixing chamber 6 to the inside of the catalytic reaction chamber 8, the expansion type design structure on the expansion section enables the fuel to be completely evaporated, and meanwhile, if required, the contraction section is preferably provided with the flow disturbing column, the contraction type design and the flow disturbing column improve the flowing property, the influence of backflow and vortex on the flowing is strengthened, the gas retention time in the mixing chamber is increased, the mixing is more sufficient, and the flow is more uniform. The evenly mixed fuel-steam enters the catalytic chamber 8 for catalytic reforming reaction

The working principle of the invention is as follows:

high temperature waste gas lets in the bottom of first accommodation space 14 by casing 13 bottom high temperature waste gas import 10, and high temperature waste gas gets into the catalytic reaction region, exchanges heat with the catalyst module, provides the required heat of steam reforming, and the gained reformed gas of catalytic reforming is discharged from reformed gas export 9, through the catalytic reaction heat transfer back, and high temperature waste gas changes the middle temperature waste gas about 400 ℃.

The medium-temperature waste gas obtained after the high-temperature waste gas is subjected to heat exchange and temperature reduction enters the heat exchange evaporator 2 from the medium-temperature waste gas connector 11 and exchanges heat with liquid water introduced from the liquid water inlet 1, and the liquid water is turned into steam; the heat exchange evaporator 2 adopts a shell-and-tube type countercurrent heat exchange method, and simultaneously, in order to improve the heat exchange efficiency and increase multistage fins for strengthening heat exchange, other modes can be utilized outside a tube shell for auxiliary heat supply; the high temperature water vapor then enters the cyclone 3 through a pipe.

The water vapour generated by the evaporation chamber enters the cyclone 3, the cyclone 3 being shown in a top view in fig. 2. The steam can flow into the cyclone 3 tangentially through four tangential pipes in fig. 2 to generate swirling steam, or can be generated by axial swirling of the vane 20 arranged at an angle to the axial direction in fig. 3. The generated rotational flow is re-introduced into the mixing chamber 6.

In the mixing chamber 6, a pressure cyclone atomizing nozzle 5 is adopted to atomize the fuel into droplets with the diameter of 10-30 microns, the droplets are sprayed into cyclone high-temperature water vapor to carry out heat exchange evaporation and are fully mixed along a flow channel, meanwhile, a high-boiling-point residue collecting tank 7 is arranged on the mixing chamber 6, and the high-boiling-point residue which is not evaporated is collected in the high-boiling-point residue collecting tank 7. In order to improve the mixing effect, an expansion section-contraction section-expansion section type cavity is adopted, the expansion type design enables the fuel to be completely evaporated, meanwhile, a turbulence column can be added in the contraction section if needed, the contraction type design and the turbulence column improve the flowing property, the influence of backflow and turbulence on flowing is enhanced, the gas residence time in the mixing chamber is prolonged, the mixing is more sufficient, and the flow is more uniform. The uniformly mixed fuel-steam enters the catalytic reaction chamber 8 to perform catalytic reforming reaction.

In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application.

The foregoing description has described specific embodiments of the present invention. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.

Claims

1. A fuel catalytic reformer based on waste heat utilization is characterized by comprising a heat exchange evaporator (2), a cyclone (3), a mixing chamber (6), a collecting tank (7), a catalytic reaction chamber (8) and a shell (13);

the heat exchange evaporator (2) comprises a first flow passage (15) and a second flow passage (16);

a cyclone (3), a mixing chamber (6) and a catalytic reaction chamber (8) which are sequentially connected are sequentially arranged in the shell (13) from top to bottom, and a first accommodating space (14) is formed between the outer walls of the cyclone (3), the mixing chamber (6) and the catalytic reaction chamber (8) and the shell (13);

high-temperature waste gas enters the bottom of the first accommodating space (14) through the high-temperature waste gas inlet (10), flows to the top of the first accommodating space (14), is changed into medium-temperature waste gas, enters the top of the first flow channel (15) through the medium-temperature waste gas connecting port (11), and is discharged from the bottom of the first flow channel (15) through the low-temperature waste gas outlet (12);

liquid water enters the bottom of the second flow channel (16) through the liquid water inlet (1) and enters the cyclone (3), the mixing chamber (6) and the catalytic reaction chamber (8) from the top of the second flow channel (16) and then is discharged from the reformed gas outlet (9), the mixing chamber (6) is connected with the fuel inlet (4), and a cavity space arrangement from the expansion section to the contraction section and then to the expansion section is formed from the mixing chamber (6) to the inside of the catalytic reaction chamber (8);

the medium-temperature waste gas in the first flow passage (15) and the liquid water in the second flow passage (16) perform heat transfer in a countercurrent mode, so that the medium-temperature waste gas is changed into low-temperature waste gas, and the liquid water is changed into water vapor.

2. The catalytic reformer for fuel based on waste heat utilization as claimed in claim 1, wherein the heat exchanging evaporator (2) adopts a shell-and-tube heat exchanging structure, wherein the first flow passage (15) is a shell pass, the second flow passage (16) is a tube pass, and the number of the second flow passage (16) is one or more.

3. The catalytic reformer of claim 2, wherein the second flow passage (16) extends circumferentially with multiple levels of ribs.

4. The waste heat utilization based fuel catalytic reformer according to claim 1, characterized in that the fuel inlet (4) injects fuel into the mixing chamber (6) through a pressure swirl atomizing nozzle (5).

5. The waste heat utilization based fuel catalytic reformer according to claim 4, characterized in that the pressure swirl atomizing nozzle (5) sprays fuel into the mixing chamber (6) as droplets of 10-30 μm diameter size.

6. The catalytic reformer for fuels based on waste heat utilization according to claim 1, characterized in that the swirler (3) adopts any one of the following structures:

-the swirl outlets (17) are a plurality of outlet pipes which are uniformly or non-uniformly arranged in a clockwise or counterclockwise tangential direction;

the device comprises a rotational flow outlet header pipe (18) and a fixed shaft (19), wherein a plurality of rotational vanes (20) are sequentially and uniformly arranged between the rotational flow outlet header pipe (18) and the fixed shaft (19), rotational flow channels are formed between two adjacent rotational vanes (20), and the water vapor forms a rotational air flow through the rotational flow channels.

7. The catalytic reformer for fuels based on residual heat utilization according to claim 1, characterized in that a high-boiling-point residue collection tank (7) is provided on the mixing chamber (6).

8. The catalytic reformer for fuel based on waste heat utilization as claimed in claim 1, wherein a turbulence column is provided on the contraction section.

9. The catalytic reformer of the waste heat utilization-based fuel according to claim 1, characterized in that the heat exchanging evaporators (2) are arranged along a circumferential direction of the casing (13).