A fuel online reforming system for blending H2 and CO

Abstract

This invention relates to an online fuel reforming system for blending H2 and CO. This online fuel reforming system for blending H2 and CO is suitable for natural gas engines and includes a fuel supply unit; an air compressor that outputs compressed air through a pipeline to mix with natural gas output from the fuel supply unit to form a first mixed gas; a mixed gas heater that receives and heats the first mixed gas through a pipeline; and a reforming reactor that receives the first mixed gas and performs a reforming reaction to generate a second mixed gas rich in H2 and CO. The second mixed gas output from the reforming reactor is mixed with air in the intake manifold of the natural gas engine to form a third mixed gas. This invention provides an online fuel reforming system for blending H2 and CO, which can improve the in-cylinder combustion speed of a natural gas engine, further broaden the lean combustion limit of the natural gas engine, and simultaneously promote stable lean combustion in the natural gas engine, reducing HC and NOx emissions.

Description

Technical Field

[0001] This invention relates to the field of natural gas engine technology, and more particularly to a fuel online reforming system for blending H2 and CO. Background Technology

[0002] Given the depletion of traditional fossil fuel reserves and increasingly stringent vehicle emission regulations, the search for alternative energy sources that simultaneously reduce harmful emissions has become a hot topic in the field of internal combustion engine research. Natural gas, as an alternative fuel with abundant reserves, high energy density, ease of transportation, and good combustion performance, can reduce carbon dioxide, sulfur oxide, and particulate matter emissions from natural gas engines, and therefore has been vigorously developed.

[0003] Natural gas engines often employ lean-burn technology to reduce nitrogen oxide (NOx) emissions. Methane (CH4) burns slowly, and an excessively high air-fuel ratio can lead to unstable combustion in the engine, or even misfire, resulting in increased emissions of unburned hydrocarbons (HC) and carbon monoxide (CO). Existing research indicates that adding hydrogen (H2) and carbon monoxide (CO) to natural gas can improve fuel combustion speed, mitigate engine misfires, and achieve stable lean-burn combustion, thereby reducing HC and NOx emissions.

[0004] Early hydrogen blending was typically achieved using onboard hydrogen tanks. In-line fuel reforming technology produces reformed gas through a reforming unit, which can be directly fed into the intake manifold of a natural gas engine, thus achieving the desired hydrogen blending effect. The reforming reaction primarily involves the partial oxidation of fuel and air.

[0005] The recently developed Dedicated-EGR technology produces hydrogen (H2) and carbon monoxide (CO) in one or more cylinders under rich combustion conditions, and then mixes the hydrogen (H2) and carbon monoxide (CO) back into the cylinder for combustion through exhaust gas recirculation. However, D-EGR technology typically suffers from uneven distribution of recirculated exhaust gas, and it is difficult to precisely control the hydrogen (H2) and carbon monoxide (CO) content in the recirculated exhaust gas. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, this invention proposes an online fuel reforming system for blending H2 and CO, suitable for natural gas engines. This system can improve the in-cylinder combustion speed of natural gas engines, further broaden the lean combustion limit of natural gas engines, and simultaneously promote stable lean combustion in natural gas engines, thereby reducing HC and NOx emissions.

[0007] Specifically, this invention proposes an online fuel reforming system for blending H2 and CO, suitable for natural gas engines, comprising:

[0008] Fuel supply unit for supplying natural gas;

[0009] An air compressor outputs compressed air through a pipeline, which is then mixed with natural gas output from the fuel supply device to form a first mixed gas.

[0010] A mixed gas heater receives and heats the first mixed gas through a pipeline;

[0011] The reforming reactor receives the first mixed gas output from the mixed gas heater through a pipeline and carries out a reforming reaction to generate a second mixed gas rich in H2 and CO. The second mixed gas output from the reforming reactor is mixed with air in the intake pipeline of the natural gas engine to form a third mixed gas.

[0012] According to one embodiment of the present invention, the molar ratio of methane in the natural gas supplied by the fuel supply device to oxygen in the compressed air supplied by the air compressor is 1.7 to 2.2.

[0013] According to one embodiment of the present invention, the mixed gas heater heats the first mixed gas so that the temperature of the first mixed gas entering the reforming reactor is in the range of 300 to 500°C.

[0014] According to one embodiment of the present invention, the mixed gas heater is cylindrical and has an electrically heated inner wall and a spiral gas coil arranged along the axial direction. The mixed gas heater heats the first mixed gas flowing through the spiral gas coil through the electrically heated inner wall.

[0015] According to one embodiment of the present invention, the ratio of the radius of the electrically heated inner wall to the helical radius of the spiral gas coil is 1.2 to 1.5.

[0016] According to one embodiment of the present invention, the reforming reactor includes an intermediate section and an inlet encapsulation section and an outlet encapsulation section disposed at both ends of the intermediate section. The intermediate section is cylindrical, and the inlet encapsulation section and the outlet encapsulation section are hollow cones.

[0017] According to one embodiment of the present invention, a honeycomb structure is provided in the middle part, and a catalyst with noble metal Rh as the active component is coated on the surface of the honeycomb structure.

[0018] According to one embodiment of the present invention, a gas guiding device is provided at the inlet to guide the second mixed gas into the honeycomb structure, and a temperature sensor is provided inside the honeycomb structure.

[0019] According to one embodiment of the present invention, the volume fraction of H2 in the second mixed gas is 15-35%.

[0020] According to one embodiment of the present invention, the volume fraction of H2 in the third mixed gas is 1-2%.

[0021] This invention provides an online reforming system for blending H2 and CO, suitable for natural gas engines. By blending reformed gas rich in H2 and CO into natural gas and then delivering it to the natural gas engine, the in-cylinder combustion speed of the natural gas engine can be improved, further expanding the lean combustion limit of the natural gas engine. At the same time, it promotes stable lean combustion of the natural gas engine and reduces the emissions of HC and NOx.

[0022] It should be understood that the above general description and the following detailed description of the invention are exemplary and illustrative, and are intended to provide further explanation of the invention as described in the claims. Attached Figure Description

[0023] The accompanying drawings are included to provide a further understanding of the invention. They are incorporated in and constitute a part of this application. The drawings illustrate embodiments of the invention and, together with this specification, serve to explain the principles of the invention.

[0024] In the attached image:

[0025] Figure 1 A schematic diagram of a fuel online reforming system for blending H2 and CO according to an embodiment of the present invention is shown.

[0026] Figure 2 yes Figure 1 A schematic diagram of the structure of the mixed gas heater.

[0027] Figure 3 yes Figure 1 A schematic diagram of the reforming reactor in the diagram.

[0028] The above figures include the following reference numerals:

[0029] 100 fuel online reforming system for blending H2 and CO

[0030] Fuel supply device 101

[0031] Air compressor 102

[0032] Mixed gas heater 103

[0033] Reformer 104

[0034] Natural gas engine 105

[0035] Electric heating inner wall 106

[0036] Spiral gas coil 107

[0037] Middle section 108

[0038] Entry packaging section 109

[0039] Export Packaging Department 110

[0040] honeycomb structure 111

[0041] Gas guiding device 112

[0042] Temperature sensor 113 Detailed Implementation

[0043] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0044] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0045] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0046] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0047] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0048] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0049] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application. In addition, although the terminology used in this application is selected from commonly known and used terms, some terms mentioned in this application's specification may have been chosen by the applicant according to his or her judgment, and their detailed meanings are explained in the relevant sections of this description. Moreover, this application should be understood not only through the actual terms used, but also through the meaning implied by each term.

[0050] Figure 1 A schematic diagram of an online reforming system for blending H2 and CO according to an embodiment of the present invention is shown. As shown in the figure, the present invention provides an online reforming system 100 for blending H2 and CO suitable for a natural gas engine 105, which mainly includes a fuel supply device 101, an air compressor 102, a mixed gas heater 103, and a reforming reactor 104.

[0051] The fuel supply device 101 is used to supply natural gas. The fuel supply device 101 is generally a gas storage tank for storing natural gas.

[0052] Furthermore, the air compressor 102 outputs compressed air through a pipeline. This compressed air is mixed with natural gas output from the fuel supply device 101 to form a first mixed gas.

[0053] The mixed gas heater 103 receives and heats the first mixed gas through a pipeline.

[0054] The reforming reactor 104 receives the first mixed gas output from the mixed gas heater 103 through a pipeline and performs a reforming reaction to generate a second mixed gas rich in H2 and CO. The second mixed gas output from the reforming reactor 104 is mixed with air in the intake pipe of the natural gas engine 105 to form a third mixed gas, which then enters the cylinder of the natural gas engine 105 for combustion. It should be noted that the natural gas engine 105 can simultaneously receive natural gas from the fuel supply device 101 through its intake pipe, or directly inject natural gas into the cylinder of the natural gas engine 105 through other pipelines. In this embodiment, the online reforming and blending system 100 for H2 and CO directly introduces the natural gas supplied by the fuel supply device 101 into the intake pipe of the natural gas engine 105 to mix with the third mixed gas before entering the cylinder of the natural gas engine 105 for combustion.

[0055] The online reforming and blending system 100 provided by this invention utilizes the partial oxidation reforming reaction between natural gas and oxygen (O2) in the air to produce reformed gas rich in H2 and CO, thereby achieving online production of H2 and CO. After being mixed with natural gas again, it is used as fuel for a natural gas engine 105. This system avoids the need for additional fuel storage devices or hydrogen storage tanks, improving system safety and reducing the overall system cost. The H2 and CO in the reformed reaction gas can increase the in-cylinder combustion rate, further widening the lean combustion limit of the natural gas engine 105, while promoting stable lean combustion in the natural gas engine 105 and reducing HC and NOx emissions.

[0056] Preferably, the molar ratio of methane in the natural gas supplied by the fuel supply device 101 to oxygen in the compressed air supplied by the air compressor 102 is 1.7 to 2.2. The air compressor 102 and the fuel supply device 101 control the natural gas content in the first mixed gas by controlling the intake volume of compressed air and natural gas, respectively, to achieve different subsequent reforming reaction conditions. In other words, before the first mixed gas enters the mixed gas heater 103, the molar ratio of methane to oxygen in the first mixed gas is 1.7 to 2.2.

[0057] Preferably, the mixed gas heater 103 heats the first mixed gas to ensure that the temperature of the first mixed gas entering the reforming reactor 104 is in the range of 300–500°C. Specifically, the mixed gas heater 103 changes the inlet temperature of the reforming reactor 104 by controlling its heating power, and the H2 and CO component contents in the second mixed gas obtained after passing through the reforming reactor 104 are different due to the different temperatures of the first mixed gas.

[0058] Figure 2 yes Figure 1 A schematic diagram of the structure of the gas-mixing heater is shown. Preferably, the gas-mixing heater 103 is cylindrical. It contains an electrically heated inner wall 106 matching the shape of the gas-mixing heater 103, and a spiral gas coil 107 arranged axially. The gas-mixing heater 103 uniformly heats the first mixed gas flowing through the spiral gas coil 107 through the electrically heated inner wall 106. The spiral gas coil 107, made of stainless steel, extends the flow path of the first mixed gas through the gas-mixing heater 103, effectively increasing the heating time of the first mixed gas. More preferably, the ratio of the radius of the electrically heated inner wall 106 to the spiral radius of the spiral gas coil 107 is 1.2 to 1.5, which improves heating efficiency and heats the first mixed gas to the ideal temperature in a shorter cycle.

[0059] Figure 3 yes Figure 1 A schematic diagram of the reforming reactor is shown. As shown, the reforming reactor 104 includes a central section 108 and an inlet sealing section 109 and an outlet sealing section 110 disposed at both ends of the central section 108. The central section 108 is cylindrical, and the inlet sealing section 109 and the outlet sealing section 110 are hollow cones.

[0060] Preferably, a honeycomb structure 111 is provided in the middle part 108 of the reforming reactor 104. The honeycomb structure 111 is composed of a single columnar porous ceramic component or a combination of multiple columnar porous ceramic components, wherein the columnar porous ceramic component has multiple through holes extending along its length and arranged side by side with partitions. The ceramic component is formed of a silicon-ceramic composite material composed of ceramic and silicon. A catalyst with a noble metal Rh as the active component is coated on the surface of the honeycomb structure 111. The noble metal Rh is a silvery-white, hard metal with high reflectivity and generally does not form oxides. This catalyst is a monolithic catalyst.

[0061] It should be noted that methane (CH4), as the main component of natural gas, undergoes partial oxidation with oxygen (O2) in reforming reactor 104, producing CO, CO2, H2, and H2O, and releasing some heat. The main reaction formulas are as follows:

[0062] CH4+1 / 2O2→CO+2H2ΔH=-36KJ / mol;

[0063] CH4+2O2→CO2+2H2OΔH=-802.2KJ / mol;

[0064] CH4+3 / 2O2→CO+2H2OΔH=-519.33KJ / mol;

[0065] CH4+O2→CO2+2H2ΔH=-318.66KJ / mol.

[0066] Preferably, a gas guiding device 112 is provided at the inlet of the reforming reactor 104 to guide the first mixed gas into the honeycomb structure 111. A temperature sensor 113 is provided inside the honeycomb structure 111. In this embodiment, the temperature sensor 113 is a thermocouple used to monitor the overall temperature of the catalyst.

[0067] Preferably, the volume fraction of H2 in the second gas mixture is 15-35%. More preferably, the volume fraction of H2 in the third gas mixture is 1-2%. The different volume fractions of H2 in the third gas mixture are used to meet the different operating conditions of the natural gas engine 105. More preferably, the present invention also includes a flow control system for controlling the flow rates of the air compressor 102 and the fuel supply device 101. According to the actual operating conditions of the natural gas engine 105, the flow rate of the first gas mixture is controlled by the flow control system. The higher the flow rate, the more heat is released in the reforming reactor 104, the higher the reaction temperature, and the higher the volume fraction of H2 in the generated second gas mixture. If the natural gas engine 105 is under high load, the flow rate of the first gas mixture is increased by the flow control system; if the natural gas engine 105 is under low load, the flow rate of the first gas mixture is decreased by the flow control system. Optionally, the present invention further includes a temperature control system for controlling the heating temperature of the mixed gas heater 103. A higher heating temperature results in a higher temperature of the first mixed gas entering the reforming reactor 104, and consequently, a higher reaction temperature in the reforming reactor 104, leading to a higher volume fraction of H2 in the generated second mixed gas. The online reforming and blending system 100 for H2 and CO can control the volume fraction of H2 in the second mixed gas through a flow control system and a temperature control system, thereby controlling the volume fraction of H2 in the third mixed gas to meet the different operating conditions of the natural gas engine 105.

[0068] It will be apparent to those skilled in the art that various modifications and variations can be made to the exemplary embodiments described above without departing from the spirit and scope of the invention. Therefore, it is intended that this invention cover modifications and variations falling within the scope of the appended claims and their equivalents.

Claims

1. A fuel online reforming system for blending H2 and CO, suitable for natural gas engines, comprising: Fuel supply unit for supplying natural gas; An air compressor outputs compressed air through a pipeline, which is then mixed with natural gas output from the fuel supply device to form a first mixed gas. A mixed gas heater receives and heats the first mixed gas through a pipeline; the mixed gas heater is cylindrical and has an electrically heated inner wall and a spiral gas coil arranged along the axial direction; the mixed gas heater heats the first mixed gas flowing through the spiral gas coil through the electrically heated inner wall. The reforming reactor receives the first mixed gas output from the mixed gas heater through a pipeline and performs a reforming reaction to generate a second mixed gas rich in H2 and CO. The second mixed gas output from the reforming reactor is mixed with air in the intake pipeline of the natural gas engine to form a third mixed gas. The reforming reactor includes a middle section and an inlet encapsulation section and an outlet encapsulation section disposed at both ends of the middle section. A honeycomb structure is provided inside the middle section. A gas guiding device is provided in the inlet encapsulation section to guide the second mixed gas into the honeycomb structure. A temperature sensor is provided inside the honeycomb structure. The volume fraction of H2 in the second gas mixture is 15-35%; the volume fraction of H2 in the third gas mixture is 1-2%.

2. The fuel online reforming and blending system for H2 and CO as described in claim 1, characterized in that, The molar ratio of methane in the natural gas supplied by the fuel supply device to oxygen in the compressed air supplied by the air compressor is 1.7 to 2.

2.

3. The fuel online reforming and blending system for H2 and CO as described in claim 1, characterized in that, The mixed gas heater heats the first mixed gas so that the temperature of the first mixed gas entering the reforming reactor is in the range of 300 to 500°C.

4. The fuel online reforming and blending system for H2 and CO as described in claim 1, characterized in that, The ratio of the radius of the electric heating inner wall to the spiral radius of the spiral gas coil is 1.2 to 1.

5.

5. The fuel online reforming system for blending H2 and CO as described in claim 1, characterized in that, The middle section is cylindrical, and the inlet and outlet sealing sections are hollow cones.

6. The fuel online reforming system for blending H2 and CO as described in claim 5, characterized in that, A catalyst with noble metal Rh as the active component is coated on the surface of the honeycomb structure.

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