Reforming Furnace

Abstract

At a center portion of a ceiling wall of a furnace body having a lateral wall between the ceiling wall and a bottom wall, there is a burner that combusts downwards. A reforming reaction tube is provided in a circumference of the burner to carry out a steam reforming treatment on a source gas. A discharging portion is an opening at an upper side portion of the lateral wall for discharging combustion gas of the burner. A cylindrical outer wall is disposed at an outer side portion of the lateral wall. In an outside space formed between the lateral wall and the outer wall, there is a steam generating heat exchanger generating steam or a mixture gas of a source gas and steam. At a lower side portion of the outer wall, there is outside discharging opening discharging the combustion gas which flows through the outside space.

Claims

1. A reforming furnace comprising: a burner combusting downwards and provided at a center portion of a ceiling wall of a furnace body having a cylindrical lateral wall disposed between the ceiling wall and a bottom wall; a reforming reaction tube provided in a circumference of the burner in suspension from the ceiling wall and configured to carry out a steam reforming treatment on a hydrocarbon-based gas as a source gas; and a discharging portion provided as an opening at an upper side portion of the lateral wall for discharging combustion gas of the burner; wherein a cylindrical outer wall is disposed at an outer side portion of the lateral wall between the ceiling wall and the bottom wall; wherein, in an outside space formed between the lateral wall and the outer wall, there is disposed a steam generating heat exchanger generating steam or a mixture gas of a source gas and steam to be supplied to an upper portion of the reforming reaction tube; and wherein at a lower side portion of the outer wall, there is provided an outside discharging opening discharging the combustion gas which flows from the discharging portion through the outside space.

2. The reforming furnace of claim 1, wherein the steam generating heat exchanger is configured with a heat conducting pipe being disposed in a spiral form along an outer circumference of the lateral wall.

3. The reforming furnace of claim 2, wherein: the reforming reaction tube comprises: an outer tube having a closed bottom portion and a supported upper end side; an inner tube disposed inside the outer tube, the inner tube having an opened bottom portion and a supported upper end side; and a plurality of reaction tube portions charged with a catalyst and disposed between the outer tube and the inner tube, the reaction tube portions being disposed side by side with spacing therebetween along a circumference of the burner.

4. The reforming furnace of claim 1, wherein between the steam generating heat exchanger and the outer wall in the outside space, there is provided an air preheating heat exchanger for preliminarily heating air to be supplied to the burner.

5. The reforming furnace of claim 4, wherein: the air preheating heat exchanger has a cylindrical configuration in which air is caused to flow between a cylindrical inside wall and a cylindrical outside wall; an air introducing portion is provided at a lower side portion of the air preheating heat exchanger; and a plurality of air supplying pipes connecting an upper side portion of the air preheating heat exchanger and the burner are disposed in a radial layout along the circumference of the burner and provided inside the ceiling wall.

6. The reforming furnace of claim 2, wherein: the reforming reaction tube comprises: an outer tube having a closed bottom portion and a supported upper end side; an inner tube disposed inside the outer tube, the inner tube having an opened bottom portion and a supported upper end side; and a plurality of reaction tube portions charged with a catalyst and disposed between the outer tube and the inner tube, the reaction tube portions being disposed side by side with spacing therebetween along a circumference of the burner.

7. The reforming furnace of claim 2, wherein between the steam generating heat exchanger and the outer wall in the outside space, there is provided an air preheating heat exchanger for preliminarily heating air to be supplied to the burner.

8. The reforming furnace of claim 3, wherein between the steam generating heat exchanger and the outer wall in the outside space, there is provided an air preheating heat exchanger for preliminarily heating air to be supplied to the burner.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] FIG. 1 is a front view in vertical section showing a reforming furnace,

[0048] FIG. 2 is a plan view showing layout of air supplying pipes in the reforming furnace, and

[0049] FIG. 3 is a partially omitted front view in vertical section showing a reaction tube.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Embodiment

[0050] Next, an embodiment of the present invention will be explained with reference to the accompanying drawings.

[0051] (General Configuration of Reforming Device)

[0052] As shown in FIG. 1, a reforming furnace is used for reforming a source gas G which can be a hydrocarbon-based gas such as a natural gas, naphtha, etc. into a reformed gas K having enriched hydrogen content through a steam reforming treatment thereof and the reforming furnace includes a furnace body H provided with a reforming reaction tube 1 and a burner B for heating this reforming reaction tube 1.

[0053] The furnace body H includes a ceiling wall 2U, a bottom wall 2D, and a cylindrical lateral wall 2S disposed between the ceiling wall 2U and the bottom wall 2D.

[0054] And, at a center portion of the ceiling wall 2U of the furnace body H, a burner B is provided to effect combustion downwards, and at an upper side portion of the lateral wall 2S, a discharging portion 2E is formed as an opening through which combustion gas of the burner B is to be discharged.

[0055] A plurality of reaction tube portions A together constituting the reforming reaction tube 1 are provided in the circumference of the burner B in suspension from the ceiling wall 2U of the furnace body H.

[0056] More particularly, as shown in FIG. 1 and FIG. 2, the reforming reaction tube 1 is configured with the plurality of reforming reaction tube portions A thereof suspended from the ceiling wall 2U of the furnace body H being arranged side by side with a spacing therebetween along the circumference of the burner B.

[0057] Incidentally, in the instant embodiment, there is disclosed an example in which four reaction tube portions A are provided as “the plurality of reaction tube portions A”. However, it is also possible to embody with providing three or more or five or more reaction tube portions A.

[0058] Further, as shown in FIG. 1, an outer wall 2G having a cylindrical shape is provided at an outside portion of the lateral wall 2S of the furnace body H between the ceiling wall 2U and the bottom wall 2D.

[0059] And, in an outside space F formed between the lateral wall 2S and the outer wall 2G, there is disposed a steam generating heat exchanger J generating steam to be supplied to an upper portion of the reforming reaction tube. Further, at a lower side portion of the outer wall 2G, there is provided an outside discharging opening 2Z discharging the combustion gas which flows from the discharging portion 2E through the outside space F.

[0060] Moreover, as shown in FIG. 1, between the steam generating heat exchanger J and the outer wall 2G in the outside space F, there is provided an air preheating heat exchanger N for preliminarily heating air to be supplied to the burner B.

[0061] (Details of Reaction Tube Portions)

[0062] Each reaction tube portion A, as shown in FIG. 3, includes an outer tube 3 having a closed bottom portion and an inner tube 4 disposed inside the outer tube 3. The inner tube 4 has its bottom portion opened and between the outer tube 3 and the inner tube 4, catalyst S in the form of grains is charged to form a charged portion.

[0063] An upper end side portion of the outer tube 3 is supported to the ceiling wall 2U by extending through this ceiling wall 2U of the furnace body H. An upper end side portion of the inner tube 4 is supported to a pipe upper wall 3u by extending through this pipe upper wall 3u of the outer tube 3.

[0064] Incidentally, between the outer tube 3 and the inner tube 4, a porous supporting body T receiving and supporting the catalyst S is provided as being supported to a lower end portion of the inner tube 4.

[0065] To a portion of the outer tube 3 protruding upwards from the ceiling wall 2U, there is connected a source gas pipe 5 for introducing source gas G, and to a portion of the inner tube 4 protruding from the pipe upper wall 3u of the outer tube 3, there is connected a reformed gas guiding pipe 6 for guiding the reformed gas K.

[0066] Incidentally, though not shown, the source gas pipe 5 is provided to branch to respective outer tubes 3 of the plurality of (four) reaction tube portions A.

[0067] Similarly, the reformed gas guiding pipe 6 is to be provided to branch to respective inner tubes 4 of the plurality of (four) reaction tube portions A.

[0068] Incidentally, to the source gas pipe 5, the steam generated by the steam generating heat exchanger J is to be supplied. And, through the source gas pipe 5, the source gas S and steam in a mixed state are supplied to the outer tubes 3.

[0069] In the reaction tube portion A, the outer tube 3 is heated to a high temperature (e.g. an average temperature of 800° C. approximately) as being heated to a target temperature for reforming reaction by the burner B and in association therewith, the catalyst S and the inner tube 4 are heated to a temperature lower than the outer tube 3 (e.g. an average temperature of 650° C. approximately)

[0070] And, as the source gas G mixed with steam introduced from the source gas pipe 5 flows downwards through the charged portion of the catalyst S between the outer tube 3 and the inner tube 4, the source gas G is reformed into the reformed gas K having enriched hydrogen content through a steam reforming treatment and after this reformed gas K passes upwards through the inside the inner tube 4, the gas is discharged through the reformed gas guiding pipe 6.

[0071] Incidentally, the reformed gas K discharged through the reformed gas guiding pipe 6, though explanation of details thereof omitted herein, will be conveyed to a CO reformer in which carbon monoxide contained in the reformed gas K is reformed into carbon dioxide by a CO reformer and then supplied to a pressure swing adsorption (PSA) device, whereby a final product gas having enriched hydrogen content will be produced.

[0072] (Details of Steam Generating Heat Exchanger)

[0073] The steam generating heat exchanger J, as shown in FIG. 1, is configured with a heat conducting pipe 7 arranged in a spiral form along the outer circumference of the lateral wall 2S of the furnace body H.

[0074] More particularly, at a lower end portion of the heat conducting pipe 7, there is formed a pure water introducing pipe portion 7a to which pure water W is supplied and at an upper end portion of the heat conducting pipe 7, there is formed a steam discharging pipe portion 7b for supplying steam to the source gas pipe 5.

[0075] Therefore, the steam generating heat exchanger J is configured to generate steam by causing the pure water W supplied to the pure water introducing portion 7a to flow through the inside of the heat conducting pipe 7 which is heated by the combustion gas flowing in the outside space F and the generated steam is supplied to the source gas pipe 5 via the steam discharging pipe portion 7b.

[0076] (Details of Air Preheating Heat Exchanger)

[0077] The air preheating heat exchanger N, as shown in FIG. 1 and FIG. 2, is configured in a cylindrical shape in which air is caused to flow through between a cylindrical inside wall 8n and a cylindrical outside wall 8g.

[0078] And, at a lower side portion of the air preheating heat exchanger N, an air introducing portion 8d is provided.

[0079] A plurality of air supplying pipes 9 connecting between the upper side portion of the air preheating heat exchanger N and the burner B are arranged radially along the circumference of the burner and provided inside the ceiling wall 2U of the furnace body H.

[0080] Therefore, the air preheating heat exchanger N is configured such that combustion air R supplied to the air introducing portion 8d is caused to flow through between the inside wall 8n and the outside wall 8g heated by the combustion gas flowing in the outside space F, thus being heated to a high temperature state and this air heated to such high temperature state through the air supplying pipes 9 is supplied to the burner B.

[0081] Incidentally, though details of the arrangement of the burner B are omitted herein, the burner B is connected not only to the air supplying pipes 9, but also to a fuel gas pipe 10 for supplying fuel gas M and configured such that the fuel gas M supplied via the fuel gas pipe 10 is combusted with the combustion air supplied via the air supplying pipes 9.

Other Embodiments

[0082] Next, other embodiments will be described respectively.

[0083] (1) In the foregoing embodiment, there was disclosed a case in which the reforming reaction pipe 1 is configured with a plurality of reaction pipe portions A thereof arranged side by side with a spacing therebetween along the circumference of the burner B. Alternatively, the reforming reaction tube 1 may be configured such that the catalyst S is charged to the inside of a double-tube tubular member covering the circumference of the burner B. And, the specific arrangement of the reforming reaction tube 1 may be modified in many ways appropriately.

[0084] (2) In the foregoing embodiment, there was disclosed a case in which the steam generating heat exchanger J generates steam with supply of pure water W thereto. However, it is also possible to embody the steam generating heat exchanger J such that this generates mixture gas of the source gas G and steam with supply of the source gas G and pure water W thereto.

[0085] (3) In the foregoing embodiment, there was disclosed a case in which in the steam generating heat exchanger J, the heat conducting pipe 7 is disposed in a spiral form along the outer circumference of the lateral wall 2S of the furnace body H. However, various modes of steam generating heat exchanger J are possible such as one configured as a fin-tube type heat exchanger.

[0086] Incidentally, the arrangements disclosed in the foregoing embodiment (including the modified embodiments) can be used in any combination with the arrangement(s) disclosed in the other embodiment(s), unless contradiction results from such combining. Further, it is understood that the embodiments disclosed in this detailed disclosure are only exemplary, and embodiments of the present invention are not limited thereto, but various modifications may be made appropriately within a range not deviating from the objects of the present invention.

DESCRIPTION OF SIGNS

[0087] 1: reforming reaction tube [0088] 2D: bottom wall [0089] 2E: discharging portion [0090] 2G: outer wall [0091] 2S: lateral wall [0092] 2U: ceiling wall [0093] 2Z: outside discharging opening [0094] 3: outer tube [0095] 4: inner tube [0096] 7: heat conducting pipe [0097] 8d: air introducing portion [0098] 8n: inside wall [0099] 8g: outside wall [0100] 9: air supplying pipe [0101] A: reaction tube portion [0102] B: burner [0103] J: steam generating heat exchanger [0104] N: air preheating heat exchanger [0105] S: catalyst