Heating device

Abstract

To provide a heating device configured so that it can prevent a member for partitioning hydrocarbon and exhaust in a heat exchange part from corroding due to the hydrocarbon.SOLUTION: A heating device for hydrocarbon to be thermally decomposed into carbon and hydrogen includes: a burner; and a heat exchange part which, while partitioning exhaust discharged from the burner and the hydrocarbon, transfers heat from the exhaust to the hydrocarbon. The burner is configured to combust fuel with an air ratio of less than 1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heating device. [Background technology]

[0002] For example, Patent Document 1 listed below describes an apparatus for extracting hydrogen by thermally decomposing hydrocarbon gases such as methane using a catalyst. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-24997 Summary of the Invention [Problem to be solved by the invention]

[0004] To pyrolyze hydrocarbon gas, it is necessary to heat the hydrocarbon gas. However, if the hydrocarbon gas is indirectly heated using combustion gas, there is a risk of corrosion of the components that transfer the heat of the combustion gas to the hydrocarbon gas. In other words, if the temperature of the components becomes excessively high, there is a risk of the components being corroded by the hydrocarbons. [Means for solving the problem]

[0005] The means for solving the above problems and their effects will be described below. A heating device for hydrocarbons that are thermally decomposed into carbon and hydrogen, the heating device comprising: a burner; and a heat exchanger that separates exhaust gas discharged from the burner from the hydrocarbons and transfers heat from the exhaust gas to the hydrocarbons, the burner being configured to combust fuel with an air ratio less than 1.

[0006] In the above configuration, the air ratio of the burner is set to be less than 1. This makes it possible to prevent the temperature of the exhaust gas from becoming excessively high, compared to when the air ratio is set to 1 or more. This makes it possible to prevent the member that separates the hydrocarbons from the exhaust gas in the heat exchange unit from corroding due to the hydrocarbons. Furthermore, compared to when the air ratio is set to 1 or more, it is possible to prevent an exothermic reaction from occurring even if the partitioning member is damaged and air on the burner side leaks to the hydrocarbon side. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram showing the configuration of a hydrogen purification system according to a first embodiment. [Figure 2] FIG. 2 is a diagram showing the configuration of a hydrogen purification system according to a second embodiment. [Figure 3] FIG. 10 is a diagram showing the configuration of a hydrogen purification system according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] First Embodiment The first embodiment will be described below with reference to the drawings. Fig. 1 shows the configuration of a hydrogen generation system 1. A burner 10 shown in Fig. 1 is supplied with hydrogen as fuel and air pressurized by a compressor 12. It is desirable that hydrogen also be supplied at a pressure higher than atmospheric pressure.

[0009] The burner 10 burns hydrogen at an air ratio λ1. The air ratio λ1 is smaller than 1. However, the air ratio λ0 at the ignition section of the burner 10 that ignites the fuel is locally greater than the air ratio λ1. This is a setting to ensure reliable combustion of hydrogen. The air ratio λ0 may be greater than 1.

[0010] The exhaust gas, which is a mixture of air and hydrogen burned in the burner 10, is supplied to the heat exchanger 20. The pressure pf of the exhaust gas supplied to the heat exchanger 20 is higher than atmospheric pressure. The exhaust gas also contains a large amount of hydrogen, which is unburned fuel.

[0011] Methane pressurized by the compressor 14 is supplied to the heat exchanger 20. The methane supplied to the compressor 14 is the methane supplied to the hydrogen generation system 1. In other words, the methane supplied to the compressor 14 is a raw material for hydrogen to be generated by the hydrogen generation system 1. The heat exchanger 20 is configured to heat the methane using the heat of the exhaust gas discharged from the burner 10 without bringing the methane into contact with the exhaust gas. Note that in FIG. 1 , due to space limitations, the methane inlet and the exhaust gas inlet are shown at the same end of the heat exchanger 20. In reality, the heat exchanger 20 may be configured, for example, such that the upstream side of the exhaust gas passage and the downstream side of the methane passage are aligned.

[0012] The exhaust gas that has passed through the heat exchanger 20 is supplied to the burner 22 as fuel. Air pressurized by the compressor 12 is also supplied to the burner 22. The burner 22 burns the supplied fuel at an air ratio λ2. The air ratio λ2 is smaller than 1. However, at the ignition section of the burner 22 that ignites the fuel, air pressurized by the compressor 12 is supplied, so that the air ratio is locally greater than the air ratio λ2. This setting is to ensure that the fuel is combusted reliably. The pressure pf of the exhaust gas discharged from the burner 22 is higher than atmospheric pressure.

[0013] The heat exchanger 24 is supplied with exhaust gas discharged from the burner 22 and methane heated by the heat exchanger 20. The heat exchanger 24 is configured to heat the methane using the heat of the exhaust gas without bringing the methane into contact with the exhaust gas discharged from the burner 22. Due to space limitations, the methane inlet and the exhaust gas inlet are shown at the same end of the heat exchanger 24 in FIG. 1. In reality, the heat exchanger 24 may be configured such that the upstream side of the exhaust gas passage and the downstream side of the methane passage are aligned, for example.

[0014] The exhaust gas that has passed through the heat exchanger 24 is supplied as fuel to the burner 26. Air compressed by the compressor 12 is also supplied to the burner 26. The burner 26 combusts the supplied fuel at an air ratio λ3. The air ratio λ3 in the most downstream heat exchanger 24 may be equal to or greater than 1. The pressure pf of the exhaust gas discharged from the burner 26 is higher than atmospheric pressure.

[0015] The heat exchanger 28 is supplied with exhaust gas discharged from the burner 26 and methane heated by the heat exchanger 24. The heat exchanger 28 is configured to heat the methane using the heat of the exhaust gas without bringing the methane into contact with the exhaust gas discharged from the burner 26. Due to space limitations, the methane inlet and the exhaust gas inlet are shown at the same end of the heat exchanger 28 in FIG. 1. In reality, the heat exchanger 28 may be configured such that the upstream side of the exhaust gas passage and the downstream side of the methane passage are aligned, for example.

[0016] The methane heated by the heat exchanger 28 is supplied to the reactor 30. The reactor 30 is configured to thermally decompose the methane into hydrogen and carbon. The reactor 30 is equipped with a catalyst. One example of the catalyst is iron. Hydrogen, which is the target of production by the hydrogen generation system 1, as well as carbon and methane, flow out of the reactor 30. It is desirable that the hydrogen generation system 1 be equipped with a cyclone, a filter, or the like that separates carbon from the material that flows out of the reactor 30. The hydrogen generation system 1 may also be equipped with a device that separates methane from the material that flows out of the reactor 30. However, the final product of the hydrogen generation system 1 may be a mixture of methane and hydrogen.

[0017] "Actions and Effects of the Present Embodiment" The air ratio λ1 in the burner 10 and the air ratio λ2 in the burner 22 are both smaller than 1. Therefore, the temperature of the exhaust gas can be lowered compared to when the air ratio is set to 1 or more. Therefore, corrosion of the partition member separating the methane and the exhaust gas in the heat exchangers 20 and 24 can be suppressed.

[0018] The material of the partition member is preferably a metal. The material of the partition member may be, for example, a stainless steel such as austenitic stainless steel. Alternatively, the material of the partition member may be, for example, a nickel-based alloy. Alternatively, the material of the partition member may be, for example, austenitic heat-resistant steel. Alternatively, the material of the partition member may be, for example, an FeCrAl alloy.

[0019] According to the present embodiment described above, the following actions and effects can be further obtained. (1-1) The exhaust gas from the burner 10 is used as fuel for the burner 22, and the exhaust gas from the burner 22 is used as fuel for the burner 26. This allows the unburned fuel in the exhaust gas to be used effectively. The air ratio λ3 of the burner 26 may be "1". Even in this case, the temperature of the exhaust gas from the burner 26 is prevented from becoming excessively high due to the influence of products generated by the combustion of hydrogen upstream.

[0020] (1-2) The heat exchangers 20, 24, and 28 for heating methane as a raw material supplied to the hydrogen generation system 1 are connected in series to the methane. As a result, the methane is heated by each of the heat exchangers 20, 24, and 28 before being supplied to the reactor 30. This makes it easier to increase the temperature of the methane compared to when the methane is heated only by the exhaust gas from one burner.

[0021] <Second embodiment> The second embodiment will be described below with reference to the drawings, focusing on the differences from the first embodiment.

[0022] The configuration of the hydrogen generation system 1 according to this embodiment is shown in Fig. 2. In Fig. 2, the components corresponding to those shown in Fig. 1 are denoted by the same reference numerals for convenience. In this embodiment, heat exchangers 20, 24, and 28 are connected in parallel to methane as a raw material supplied to the hydrogen generation system 1.

[0023] That is, methane pressurized by the compressor 14 is supplied to each of the heat exchangers 20, 24, and 28. Then, the methane pressurized by the heat exchangers 20, 24, and 28 is supplied to the reactor 30. This makes it possible to increase the amount of methane supplied to the reactor 30 per unit time, compared to when methane heated by a single heat exchanger is supplied to the reactor 30.

[0024] <Third embodiment> The third embodiment will be described below with reference to the drawings, focusing on the differences from the first embodiment.

[0025] The configuration of the hydrogen generation system 1 according to this embodiment is shown in Fig. 3. In Fig. 3, the components corresponding to those shown in Fig. 1 are denoted by the same reference numerals for convenience. In this embodiment, the reactors 30(1) to 30(3) are connected in series. The reactors 30(1) to 30(3) are each configured to thermally decompose methane into hydrogen and carbon. The reactors 30(1) to 30(3) are each equipped with a catalyst. For example, the catalyst is iron.

[0026] That is, methane pressurized by compressor 14 is heated by heat exchanger 20 and then supplied to reactor 30(1). Materials flowing out of reactor 30(1) are heated by heat exchanger 24. Here, the materials flowing out of reactor 30(1) are hydrogen, carbon, and methane. The materials heated by heat exchanger 24 are supplied to reactor 30(2).

[0027] The material exiting reactor 30(2) is heated by heat exchanger 28. Here, the material exiting reactor 30(2) is hydrogen, carbon, and methane. The material heated by heat exchanger 28 is supplied to reactor 30(3). The material exiting reactor 30(3) is hydrogen, carbon, and methane. However, the proportion of methane in the material exiting reactor 30(3) is smaller than the proportion of methane in the material exiting reactor 30(1) and reactor 30(2).

[0028] <Correspondence> The correspondence between the matters in the above embodiment and the matters described in the "Notes" column below is as follows. Below, the correspondence is shown for each number of the solutions described in the "Notes" column. [1, 6] The heating device corresponds to the components other than the reactors 30, 30(1) to 30(3) in the hydrogen generation system 1 in Figures 1 to 3. The heat exchange unit corresponds to the heat exchangers 20, 24. The hydrocarbon corresponds to methane. The burner corresponds to the burners 10, 22. An air ratio smaller than 1 corresponds to air ratios λ1, λ2 being smaller than 1. [2] The first burner corresponds to the burner 10. The second burner corresponds to the burner 22. [3] Corresponds to Figures 1 and 3. [4] Corresponds to Figure 2. [5] Corresponds to the exhaust pressure pf being higher than atmospheric pressure. [7] The upstream air ratio corresponds to λ0. The downstream air ratio corresponds to λ1, λ2.

[0029] <Other embodiments> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0030] "About the air ratio" It is not essential that the air ratio of the ignition portion of the burner 10 be greater than the air ratio of the other portions. It is not essential that the air ratio at the ignition portion of the burner 22 be greater than the air ratio at the other portions.

[0031] "About burner fuel" The burner fuel does not necessarily have to be hydrogen. The burner fuel may be, for example, methane. Alternatively, the burner fuel may be, for example, biogas. Alternatively, the burner fuel may be, for example, ammonia. "Series connection of heat exchangers through exhaust gas flow paths" 1, the heat exchangers 20, 24, and 28 are connected in series by the exhaust gas flow path, but this is not limiting. For example, the heat exchanger 28 may be omitted. Furthermore, for example, four or more heat exchangers may be connected in series by the exhaust gas flow path.

[0032] "Series connection of reactors" Although the reactors 30(1) to 30(3) are connected in series in FIG. 3, this is not limiting. For example, the reactor 30(3) may be omitted. Furthermore, for example, four or more reactors may be connected in series. In this case, the fluid supplied to each reactor may be heated by a heat exchanger connected to each other in series by an exhaust gas flow path.

[0033] The member interposed between the series-connected reactors 30 is not limited to a heat exchanger. For example, a device such as a cyclone that removes carbon from the material flowing out of the reactors 30 may be provided.

[0034] "Connecting heat exchangers through methane distribution channels" The connection of multiple heat exchangers through the methane flow path does not necessarily have to be either a series connection or a parallel connection through the methane flow path. For example, in a case where four heat exchangers (first to fourth heat exchangers) are provided, the first and second heat exchangers may be connected in series through the methane flow path, and the third and fourth heat exchangers may be connected in series through the methane flow path. Furthermore, the first and second heat exchangers and the third and fourth heat exchangers may be connected in parallel through the methane flow path.

[0035] "On the relationship between methane distribution routes and exhaust distribution routes" 1 and 3, the downstream side of the exhaust gas flow path and the downstream side of the methane flow path are the same, but this is not limited to this. For example, methane pressurized by the compressor 14 may be heated by the heat exchanger 28, then heated by the heat exchanger 24, and then heated by the heat exchanger 20. For example, methane pressurized by the compressor 14 may be heated by the heat exchanger 28, then heated by the heat exchanger 20, and then heated by the heat exchanger 24.

[0036] "About the heat exchanger" The heat exchanger does not necessarily have to be the heat exchanger to which methane is supplied before being supplied to the reactor 30. For example, the methane itself in the reactor 30 may be heated by exhaust gas, and a member separating the hydrocarbons from the exhaust gas in the reactor 30 may serve as the heat exchanger. This member may be the wall surface of the reactor 30.

[0037] "About Hydrocarbons" The hydrocarbons that can be thermally cracked are not limited to methane. For example, propane can also be used.

[0038] <Additional Notes> 1. A heating device for hydrocarbons that are thermally decomposed into carbon and hydrogen, comprising a burner and a heat exchanger that separates the exhaust gas discharged from the burner from the hydrocarbons and transfers heat from the exhaust gas to the hydrocarbons, wherein the burner is configured to combust fuel with an air ratio less than 1.

[0039] In the above configuration, the air ratio of the burner is set to be less than 1. This makes it possible to prevent the temperature of the exhaust gas from becoming excessively high, compared to when the air ratio is set to 1 or more. As a result, it is possible to prevent the member that separates the hydrocarbons from the exhaust gas in the heat exchange unit from corroding due to the hydrocarbons.

[0040] 2. A heating device according to claim 1, wherein the burner is a first burner and is provided with a second burner, and exhaust from the first burner is supplied to the second burner as fuel. The first burner performs lean combustion with an air ratio less than 1, and therefore unburned fuel is present in the exhaust gas from the first burner. In the above configuration, the unburned fuel can be effectively used as fuel by supplying the exhaust gas from the first burner to the second burner.

[0041] 3. A heating device as described in 2 above, wherein the heat exchange unit is a first heat exchange unit and is provided with a second heat exchange unit that separates the exhaust gas discharged from the second burner from the hydrocarbons and transfers heat from the exhaust gas to the hydrocarbons, and the hydrocarbons are heated by either the first heat exchange unit or the second heat exchange unit, and then heated by the other.

[0042] In the above configuration, the hydrocarbons can be heated by both the exhaust gas from the first burner and the exhaust gas from the second burner. 4. The heating device according to claim 2, wherein the heat exchange unit is a first heat exchange unit and includes a second heat exchange unit that separates the exhaust gas discharged from the second burner from the hydrocarbons and transfers heat from the exhaust gas to the hydrocarbons, the hydrocarbons heated by the first heat exchange unit and the hydrocarbons heated by the second heat exchange unit are supplied in parallel to a reactor, and the reactor is configured to thermally decompose the hydrocarbons into carbon and hydrogen.

[0043] In the above configuration, the hydrocarbons heated by the first heat exchange unit and the hydrocarbons heated by the second heat exchange unit are supplied to the reactor, and therefore, the amount of hydrocarbons that can be supplied to the reactor can be increased compared to when only one of the first heat exchange unit and the second heat exchange unit is used to heat the hydrocarbons.

[0044] 5. The heating device according to any one of the above 1 to 4, wherein the pressure of the hydrocarbons supplied to the heat exchange section is higher than atmospheric pressure, and the pressure of the exhaust gas is higher than atmospheric pressure. In the above configuration, the difference between the pressure of the hydrocarbons in the heat exchanger and the pressure of the exhaust gas can be made smaller than when the pressure of the exhaust gas is atmospheric pressure, thereby reducing the pressure resistance requirement for the heat exchanger.

[0045] 6. The heating device according to any one of the above items 1 to 5, wherein the fuel is hydrogen. When the burner uses hydrocarbon fuel, there is a risk of soot accumulating on the heat exchanger. In contrast, in the above configuration, by using hydrogen as fuel, soot accumulation can be suppressed.

[0046] 7. The heating device according to any one of the above 1 to 6, wherein the air ratio in the burner is set smaller in the other parts than in the ignition part. In the above configuration, the ignition performance of the burner can be improved compared to when the air ratio in the burner is made uniform, and therefore the fuel can be reliably combusted in the burner. [Explanation of symbols]

[0047] 10...Burner 12...Compressor 14...Compressor 20...Heat exchanger 22...Burner 24...Heat exchanger 26...Burner 28...Heat exchanger 30...Reactor

Claims

1. 1. A heating device for hydrocarbons that are pyrolyzed into carbon and hydrogen, comprising: Burner and a heat exchange unit that separates the exhaust gas discharged from the burner from the hydrocarbons and transfers heat from the exhaust gas to the hydrocarbons, The burner is configured to combust fuel with an air ratio less than one.

2. the burner is a first burner, a second burner; 2. The heating device according to claim 1, wherein exhaust gas from said first burner is supplied to said second burner as fuel.

3. the heat exchange unit is a first heat exchange unit, a second heat exchange section that separates the exhaust gas discharged from the second burner from the hydrocarbons and transfers heat from the exhaust gas to the hydrocarbons, 3. The heating device according to claim 2, wherein the hydrocarbon is heated by one of the first heat exchange section and the second heat exchange section, and then heated by the other.

4. the heat exchange unit is a first heat exchange unit, a second heat exchange section that separates the exhaust gas discharged from the second burner from the hydrocarbons and transfers heat from the exhaust gas to the hydrocarbons, the hydrocarbons heated by the first heat exchange unit and the hydrocarbons heated by the second heat exchange unit are supplied to a reactor in parallel, 3. The heating device of claim 2, wherein the reactor is configured to pyrolyze the hydrocarbons into carbon and hydrogen.

5. the pressure of the hydrocarbons supplied to the heat exchange section is higher than atmospheric pressure; 2. The heating device according to claim 1, wherein the pressure of the exhaust gas is higher than atmospheric pressure.

6. 2. The heating device according to claim 1, wherein the fuel is hydrogen.

7. 2. The heating device according to claim 1, wherein the air ratio in the burner is set smaller in the ignition section than in the other sections.

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