JP2015157721A - Reforming apparatus and modification installation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reforming apparatus and a reforming installation which enable increasing the production quantity without an increase of the steam reforming installation serving as the primary reformer.SOLUTION: Temperature raising means 50 of raising the temperature of a reformed gas 23 reformed primarily to form a high-temperature reformed gas 23A is provided in a reformed gas supply line L13-5 between a primary reformer 14-1 and a secondary reformer 14-2 so as to raise the gas temperature of the reformed gas 23A to be introduced into the secondary reformer 14-2 by the temperature raising means 50, leading to compactification of the installation scale of the primary reformer 14-1. When the primary reformer 14-1 is used on the current scale, an increase of the quantity of the reformed gas from the secondary reformer 14-2 is attained.

Description

  The present invention relates to a reforming apparatus and reforming equipment for reforming natural gas using natural gas as a fuel for a reformer that reforms natural gas or the like.

  When producing methanol or ammonia, a reformed gas obtained by reforming natural gas or the like with a reformer is used (for example, see Patent Documents 1 and 2). When reforming natural gas with a reformer (primary reformer and secondary reformer) to obtain reformed gas, a part of natural gas is extracted before supplying natural gas to the reformer. Natural gas supplied to the reformer is reformed as fuel for the reformer.

JP-A-6-234517 JP 2000-63115 A (Patent No. 4168210)

By the way, in the conventional methods for producing methanol and ammonia as in Patent Documents 1 and 2, generally, natural gas is first compressed to the reforming pressure. And before compressing natural gas, a part of natural gas which has not been desulfurized is extracted and used as fuel for the reformer.
In the market where the production scale of ammonia, methanol and the like is increasing, for example, when producing ammonia, for example, when the scale is increased to 2000 t / D (for example, 3000 t / D or more), the equipment The limitation of the increase is the size of the steam reforming equipment, which is the primary reformer among the reformers, and has the following problems.

(1) Since the reforming reaction is an endothermic reaction, natural gas passing through the catalyst reaction tube filled with the catalyst is heated from the outside, for example, with a burner. However, as the scale increases, the number of catalyst reaction tubes increases. Increases, the heat transfer performance decreases, and the required reforming performance is not exhibited.
(2) The equipment of the primary reformer is a large size in a normal plant, and there is a problem that there is a restriction on installation when the scale further increases.
(3) In addition, there is a problem that significant equipment costs in production increase with an increase in the scale of equipment.
(4) Also, from the viewpoint of reaction efficiency, when the reaction temperature of the primary reformer is improved to cope with an increase in production scale, the reaction temperature has an upper limit due to the heat resistance of the primary reformer, There is also a problem that the reaction temperature cannot be increased even when the scale of the facility is operated as it is.

  Therefore, when the production scale is increased, the appearance of a reformer that increases the production amount without increasing the steam reforming equipment as the primary reformer is desired.

  In view of the above problems, an object of the present invention is to provide a reformer and a reforming facility that can increase the production amount without increasing the steam reforming facility as a primary reformer.

The first invention of the present invention for solving the above-mentioned problem is to supply water vapor to the raw material gas, and to make the hydrocarbon in the raw material gas primary to one or both of H _2, CO and CO _2. Using a primary reformer to be reformed and air, the hydrocarbon in the reformed gas after the primary reforming in the primary reformer is converted into H ₂ and / or one of CO ₂ and CO _2. A secondary reformer to be reformed as a reformed gas, and interposed between the primary reformer and the secondary reformer, and reformed after the primary reforming in the primary reformer A reformer characterized by having a temperature raising means for raising the temperature of the gas.

  A second invention is the reforming apparatus according to the first invention, wherein the temperature raising means is a heat exchanger using a high temperature reformed gas reformed by a secondary reformer. .

  According to a third aspect of the invention, there is provided the reformer according to the first aspect, wherein the temperature raising means is a natural gas heater or an electric heater.

  A fourth invention is the reforming apparatus according to the third invention, wherein the temperature raising means is a combination of either a natural gas heater or an electric heater and a heat exchanger.

5th invention is the 1st compression part which compresses the raw material gas containing hydrocarbon and sulfur, the 1st heat exchange part which heats the compressed said raw material gas, and sulfur contained in the heated said raw material gas a desulfurization unit for removing the minute, one or both of the said hydrocarbon feed gas reformed in one or both of H ₂ and CO and CO _2, H ₂ and CO and CO ₂ A reforming apparatus according to any one of the first to fourth aspects of the present invention for generating a reformed gas, and the compressed raw material gas with respect to the flow direction of the raw material gas; A raw material gas branch line that is partly extracted from either one or both and supplied as a combustion fuel used for heating in the reforming section, and combustion exhaust gas generated by combustion in the reforming section, The exhaust gas from the flue gas exhaust line and the reforming section for heating A second heat exchanging part for exchanging heat with the flue gas exhausted by the first heat exchanging part, the first heat exchanging part being provided in the flue gas exhaust line, The exhaust gas is used as a heating medium for the compressed raw material gas, and the second heat exchange part is provided downstream of the first heat exchange part of the combustion exhaust gas discharge line, and heat is generated in the first heat exchange part. The reforming facility is characterized in that it is used as a heating medium for the combustion air with the exchanged residual heat.

  According to the present invention, the gas temperature of the reformed gas introduced into the secondary reformer can be raised by the temperature raising means, so that the equipment scale of the primary reformer can be made compact. Alternatively, when the scale of the primary reformer is the same as the conventional one, the amount of reformed gas from the secondary reformer can be increased.

FIG. 1 is a schematic diagram of a reforming facility according to the present embodiment. FIG. 2 is a schematic diagram of the reformer according to the present embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by this Example, Moreover, when there exists multiple Example, what comprises combining each Example is also included.

A reforming apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of a reforming facility according to Embodiment 1 of the present invention. FIG. 2 is a schematic diagram of the reformer according to the present embodiment. As shown in FIG. 1, the reforming facility 10 includes a compressor (compression unit) 11, a first heat exchanger (heat exchange unit) 12, a desulfurization device (desulfurization unit) 13, and a primary reformer 14-. 1 and a secondary reformer 14-2, a reforming device 14, a denitration device (denitration unit) 15, a second heat exchanger 16, a cooling device 17, and a CO ₂ recovery device (CO ₂ recovery unit). ) 18, a raw material gas branch line L11, a combustion exhaust gas discharge line L12, and a temperature raising means 50 provided between the primary reformer 14-1 and the secondary reformer 14-2. .

  Here, in the present invention, the natural gas 21 is used as the raw material gas containing hydrocarbons and sulfur. However, the present invention is not limited to this, and any raw material gas containing hydrocarbons may be used. Gas (Liquefied Petroleum Gas: LPG), synthesis gas obtained from other hydrocarbons such as butane or naphtha, natural gas liquid (NGL), methane hydrate produced with the production of crude oil and natural gas Etc.

  The compressor 11 compresses the natural gas 21 and raises the natural gas 21 to a predetermined pressure. The natural gas 21 is supplied to the compressor 11 through the raw material gas supply line L13-1. The natural gas 21 is raised to a predetermined pressure by the compressor 11 and is heated to a high temperature, and then supplied to the first heat exchanger 12 through the raw material gas supply line L13-2.

  The first heat exchanger 12 heats the compressed natural gas 21. The first heat exchanger 12 is provided in the combustion exhaust gas discharge line L12. As the first heat exchanger 12, for example, a convection coil heat exchanger is used. The first heat exchanger 12 has the duct side as the secondary side, the combustion exhaust gas 22 is circulated in the duct, and the tube (heat transfer tube) side of the first heat exchanger 12 is the primary side. Then, as described later, the combustion exhaust gas 22 discharged from the reformer 14 is circulated in the duct as a heating medium. The first heat exchanger 12 heats the natural gas 21 by using the combustion exhaust gas 22 supplied to the outer periphery of the heat transfer tube as a heat source and circulating the natural gas 21 in the heat transfer tube.

  In addition, the 1st heat exchanger 12 is not limited to a convection coil type heat exchanger, What is necessary is just to be able to indirectly heat-exchange the natural gas 21 and the combustion exhaust gas 22. FIG.

  The natural gas 21 is heated by exchanging heat with the combustion exhaust gas 22 in the first heat exchanger 12, and then supplied to the desulfurization device 13 through the raw material gas supply line L13-3.

The desulfurization device 13 is for removing sulfur content (S content) such as hydrogen sulfide (H ₂ S) and organic sulfur compounds contained in the heated natural gas 21. A conventionally known desulfurization apparatus 13 is used, and either a wet type or a dry type can be used. In the case of wet desulfurization, for example, the S component in the natural gas 21 is absorbed by the alkali absorbing solution by gas-liquid contact using an alkali absorbing solution, and separated and removed from the natural gas 21.
Further, in the case of dry desulfurization, after adding hydrogen to natural gas, the sulfur content in natural gas 21 is changed to sulfide by a metal oxide such as iron oxide, zinc oxide, cobalt oxide, etc. Separated and removed.

  The natural gas 21 from which the S component has been removed by the desulfurization apparatus is supplied into the reforming apparatus 14 through the raw material gas supply line L13-4. The source gas supply line L13-4 is connected to the water vapor supply line L14. The water vapor 24 is supplied into the raw material gas supply line L13-4 through the water vapor supply line L14 and mixed with the natural gas 21. The natural gas 21 is supplied into the reformer 14 after the steam 24 is mixed in the steam supply line L14.

Reformer 14, the hydrocarbons in the natural gas 21, modified in either or both of H ₂ and CO and CO _2, including one or both of H ₂ and CO and CO ₂ The reformed gas 23 is generated.

  As shown in FIG. 2 showing the outline of the reformer, the reformer 14 is composed of a primary reformer 14-1 and a secondary reformer 14-2.

The primary reformer 14-1 includes a main body 14a, a catalyst reaction tube 14b, and a burner 14c. The catalyst reaction tube 14b is provided inside the main body 14a, and the catalyst reaction tube 14b includes a reforming catalyst layer including a reforming catalyst. The burner 14c is provided inside the main body 14a, burns the combustion air 26, generates combustion exhaust gas 22, and heats the catalyst reaction tube 14b. The burner 14c is connected to the air supply line L15. The combustion air 26 is supplied to the burner 14c through the air supply line L15. As will be described later, the combustion air 26 is heat-exchanged with the combustion exhaust gas 22 in the second heat exchanger 16 and heated, and then supplied to the reformer 14. The catalyst reaction tube 14b is heated by the combustion exhaust gas 22, and the natural gas 21 contacts the reforming catalyst when passing through the reforming catalyst layer of the catalyst reaction tube 14b. ), The hydrocarbons in the natural gas 21 are reformed to H ₂ and CO and CO ₂ . Thereby, the reformed gas 23 containing one or both of H ₂ and CO and CO ₂ is generated. The gas temperature of the reformed gas 23 is in the range of 400 ° C. to 1000 ° C., for example.
CH ₄ + H ₂ O → CO + 3H ₂ (endothermic reaction) (3)
CH ₄ + 2H ₂ O → CO ₂ + 4H ₂ (endothermic reaction) (4)

The secondary reformer 14-2 supplies air (oxygen) to the reformed gas 23 and secondary reforms the hydrocarbons in the natural gas 21 using a partial oxidation reaction. The second reformer 14-2 introduces the combustion air 26 heated from the outside, and the hydrocarbon in the reformed gas 23 undergoes secondary reforming to one or both of H _2, CO and CO _2. Is done.
The secondary reforming reaction is an exothermic reaction using air, but the exothermic reaction and the endothermic reaction of the formulas (3) and (4) are integrated and the reforming proceeds and the temperature is high. Is advantageous for the equilibrium reaction.

  In the present embodiment, the reformed gas 23 that has undergone primary reforming is heated to a reformed gas supply line L13-5 between the primary reformer 14-1 and the secondary reformer 14-2 to increase the temperature. A temperature raising means 50 for providing the reformed gas 23A is provided.

  Examples of the temperature raising means 50 include a natural gas heater that raises the temperature of the reformed gas 23 with the natural gas 21 and an electric heater.

Further, as shown in FIG. 2, a heat exchanger that is a temperature raising means 50 that performs heat exchange using the temperature of the outlet high temperature reformed gas 23B of the secondary reformer 14-2 may be used.
The heat exchanger 50 is provided at the intersection of the reformed gas supply line L13-5 and the reformed gas discharge line 13-6, and exchanges heat between the primary reformed gas 23 and the outlet high-temperature reformed gas 23B. The temperature of the reformed reformed gas 23 is increased to a high temperature reformed gas 23A, which is introduced into the secondary reformer 14-2.

Here, the temperature raising means (heat exchanger) 50 preferably raises the inlet temperature (T ₂ ) introduced into the secondary reformer 14-2 to at least 800 ° C. or higher.

  Further, as a temperature raising means, a natural gas heater or an electric heater and a heat exchanger may be used in combination.

The outlet gas temperature (T ₃ ) of the reformed gas 23B, which is heated by reforming of the secondary reformer 14-2, becomes predominantly the endothermic reaction as the temperature rises. Since the combustion of methane and hydrogen by oxygen relatively decreases, it becomes a substantially constant value (for example, 970 ° C.) regardless of the inlet temperature.
The heat of the reformed gas 23B from the secondary reformer 14-2 is used to heat-exchange the temperature of the reformed gas 23A at the outlet from the primary reformer 14-1, and at least 800 ° C. or higher. It is trying to become.

Table 1 shows the primary reformer outlet gas temperature (T ₁ ), secondary reformer inlet and outlet gas temperatures (T ₂ , T ₃ ), secondary reformer residual methane concentration, primary The relative load of the reformer and the primary reformer load are shown.

表１に示すように、比較例１は、熱交換器を設置していない場合（従来例）であり、試験例１〜９は熱交換器を設置した場合である。
比較例１（従来例）では、一次改質器１４−１の出口温度（Ｔ₁）は７９０℃であり、二次改質器１４−２の入口温度（Ｔ₂）も同様の７９０℃である。このときの改質器の負荷を１００とする。

As shown in Table 1, Comparative Example 1 is a case where no heat exchanger is installed (conventional example), and Test Examples 1 to 9 are cases where a heat exchanger is installed.
In Comparative Example 1 (conventional example), the outlet temperature (T ₁ ) of the primary reformer 14-1 is 790 ° C., and the inlet temperature (T ₂ ) of the secondary reformer 14-2 is also 790 ° C. is there. The load of the reformer at this time is set to 100.

On the other hand, in Test Example 1, a heat exchanger is provided and the inlet temperature (T ₂ ) of the secondary reformer 14-2 is raised to 800 ° C., so the outlet temperature of the primary reformer 14-1 ( T ₁ ) can be as low as 784 ° C. At this time, the load on the primary reformer 14-1 is reduced to 98%.
Furthermore, in Test Example 2, a heat exchanger is provided to raise the inlet temperature (T ₂ ) of the secondary reformer 14-2 to 820 ° C., so the outlet temperature (T ₁ ) of the primary reformer 14-1 ) Can be as low as 776 ° C. At this time, the load on the primary reformer 14-1 is reduced to 94%.
Furthermore, in Test Example 3, a heat exchanger is provided to raise the inlet temperature (T ₂ ) of the secondary reformer 14-2 to 850 ° C., so the outlet temperature (T ₁ ) of the primary reformer 14-1 ) Can be as low as 764 ° C. At this time, the load on the primary reformer 14-1 is reduced to 89%.
Further, in Test Example 4, a heat exchanger is provided to raise the inlet temperature (T ₂ ) of the secondary reformer 14-2 to 870 ° C. Therefore, the outlet temperature (T ₁ ) of the primary reformer 14-1 ) Can be as low as 755 ° C. At this time, the load on the primary reformer 14-1 is reduced to 86%.
Furthermore, in Test Example 5, a heat exchanger is provided to raise the inlet temperature (T ₂ ) of the secondary reformer 14-2 to 900 ° C. Therefore, the outlet temperature (T ₁ ) of the primary reformer 14-1 ) Can be as low as 743 ° C. At this time, the load on the primary reformer 14-1 is reduced to 80%.
Furthermore, in Test Example 6, a heat exchanger is provided to raise the inlet temperature (T ₂ ) of the secondary reformer 14-2 to 950 ° C., so the outlet temperature (T ₁ ) of the primary reformer 14-1 ) Can be as low as 720 ° C. At this time, the load on the primary reformer 14-1 is reduced to 71%.
Further, in Test Example 7, a heat exchanger is provided to raise the inlet temperature (T ₂ ) of the secondary reformer 14-2 to 1000 ° C. Therefore, the outlet temperature (T ₁ ) of the primary reformer 14-1 ) Can be as low as 696 ° C. At this time, the load on the primary reformer 14-1 is reduced to 62%.
Furthermore, in Test Example 8, a heat exchanger is provided to raise the inlet temperature (T ₂ ) of the secondary reformer 14-2 to 1050 ° C. Therefore, the outlet temperature (T ₁ ) of the primary reformer 14-1 ) Can be as low as 668 ° C. At this time, the load on the primary reformer 14-1 is reduced to 52%.
In Test Example 9, a heat exchanger is provided to raise the inlet temperature (T ₂ ) of the secondary reformer 14-2 to 1100 ° C. Therefore, the outlet temperature (T ₁ ) of the primary reformer 14-1 ) Can be as low as 636 ° C. At this time, the load on the primary reformer 14-1 is reduced to 42%.

Here, since the upper limit of the apparatus heat resistance temperature of the secondary reformer 14-2 is about 1000 to 1100 ° C., the upper limit of the inlet temperature (T ₂ ) is 1100 ° C.
In the case of Test Examples 6 to 9, since the heat exchange capacity of the heat exchanger is insufficient, a natural gas heater or an electric heater is additionally provided as a temperature raising means.

  For example, when the inlet temperature is raised to 850 ° C. as in Test Example 3, it becomes about 89% with respect to the scale of the primary reformer 14-1 of Comparative Example 1, and thus, for example, the size of the ammonia plant is increased. Can be supported.

  For example, the ammonia production limit when using one primary reformer 14-1 is estimated to be, for example, about 3300 t / D in the case of Comparative Example 1, but in the case of Test Example 3, it is approximately 3700 t / D. The production can be improved to a certain extent (3300 × 100/89).

As for the equipment scale, there is a reduction effect of about 5% when the production volume is the same.
Furthermore, when the temperature is raised to 850 ° C. as in Test Example 3, the manufacturing cost of the device is reduced by 7%.

  In this way, in order to increase the production amount, it is not necessary to increase the facilities for the temperature increase in the primary reformer 14-1.

  Moreover, since the gas temperature of the reformed gas 23A introduced into the secondary reformer 14-2 can be raised by the temperature raising means 50, the facility scale of the primary reformer 14-1 can be reduced. Can do. Alternatively, when the scale of the primary reformer 14-1 is the same as the conventional one, the amount of the reformed gas 23B can be increased from the secondary reformer 14-2.

  The raw material gas branch line L11 connects the downstream side of the desulfurization apparatus 13 and the air supply line L15. The raw material gas branch line L11 extracts a part of the natural gas 21 as a branch gas 21a from the downstream side of the desulfurizer 13 with respect to the flow direction of the natural gas 21 from the natural gas 21 compressed by the compressor 11, and an air supply line It mixes with the combustion exhaust gas 22 which passes L15. In this branched branch gas 21a, the S content contained in the natural gas 21 is removed by the desulfurization device 13, so the natural gas 21 not containing the S content is supplied to the air supply line L15.

  The reformed gas 23 generated by the reformer 14 is used as a raw material gas for synthesizing hydrogen, liquid hydrocarbon, methanol, ammonia, or the like. Further, the combustion exhaust gas 22 discharged from the reformer 14 is supplied to the denitration device 15 through the combustion exhaust gas discharge line L12.

The combustion exhaust gas discharge line L12 is a line for discharging the combustion exhaust gas 22 generated by burning the fuel including the natural gas 21 extracted to the raw material gas branch line L11 for fuel using the combustion air 26 in the reformer 14. is there. The combustion exhaust gas discharge line L12 includes a denitration device 15 in the middle thereof, and a reducing agent injector 28 on the upstream side of the denitration device 15. The reducing agent 29 is supplied from the reducing agent injector 28 to the combustion exhaust gas 22 while the combustion exhaust gas 22 passing through the combustion exhaust gas discharge line L <b> 12 is supplied to the denitration device 15. As the reducing agent 29, for example, ammonia (NH ₃ ), urea (NH ₂ (CO) NH ₂ ), ammonium chloride (NH ₄ Cl), or the like is used. The reducing agent 29 is supplied to the combustion exhaust gas discharge line L12 as a solution or gas containing the reducing agent 29. When the solution containing the reducing agent 29 is supplied to the combustion exhaust gas discharge line L12, the droplets of the solution containing the reducing agent 29 are evaporated and vaporized by the high-temperature ambient temperature of the combustion exhaust gas 22.

  The combustion exhaust gas 22 is supplied to the denitration device 15 through the combustion exhaust gas discharge line L12 while containing the reducing agent 29.

The denitration device 15 is provided between the reformer 14 and the first heat exchanger 12 of the combustion exhaust gas discharge line L12, and nitrogen oxide (NOx) contained in the combustion exhaust gas 22 generated by the reformer 14 Is to be removed. A conventionally known denitration device 15 is used. For example, the denitration device 15 includes a denitration catalyst layer in which a denitration catalyst for removing NOx in the combustion exhaust gas 22 is filled. The combustion exhaust gas 22 supplied into the NOx removal device 15 comes into contact with the NOx removal catalyst filled in the NOx removal catalyst layer, so that NOx in the combustion exhaust gas 22 on the NOx removal catalyst is reduced as shown in the following formula (5). The reduction reaction proceeds with 29 and is reduced and decomposed and removed into nitrogen gas (N ₂ ) and water (H ₂ O).
4NO + 4NH ₃ + O ₂ → 4N ₂ + 6H ₂ O (5)

  The combustion exhaust gas 22 is supplied to the first heat exchanger 12 after NOx in the combustion exhaust gas 22 is removed by the denitration device 15. In the first heat exchanger 12, the combustion exhaust gas 22 is heat-exchanged with the natural gas 21 to heat the natural gas 21 as described above. Thereafter, the combustion exhaust gas 22 is supplied from the first heat exchanger 12 to the second heat exchanger 16 through the combustion exhaust gas discharge line L12.

  The second heat exchanger 16 heats the combustion air 26. Similar to the first heat exchanger 12, the second heat exchanger 16 is provided in the combustion exhaust gas discharge line L12. As the second heat exchanger 16, a convection coil heat exchanger is used as in the first heat exchanger 12. The second heat exchanger 16 circulates the combustion exhaust gas 22 in the duct with the duct side as the secondary side and the combustion air 26 in the heat transfer tube with the tube (heat transfer tube) side as the primary side. The second heat exchanger 16 uses the combustion exhaust gas 22 supplied to the outside of the heat transfer tube as a heat source, causes the combustion air 26 to flow through the heat transfer tube, and heats the combustion air 26.

  The combustion exhaust gas 22 is heat-exchanged with the combustion air 26 by the second heat exchanger 16 and then supplied to the cooling device 17. The combustion air 26 is supplied to the reformer 14 after being heated by being exchanged with the combustion exhaust gas 22 by the second heat exchanger 16.

  The cooling device 17 cools the combustion exhaust gas 22. The cooling device 17 is a cooling tower in which the cooling water 30 circulates inside and outside. In the cooling device 17, the cooling water 30 is supplied from the tower top side, and the combustion exhaust gas 22 supplied into the tower is brought into gas-liquid contact with the cooling water 30 to be cooled. After the cooling water 30 comes into gas-liquid contact with the combustion exhaust gas 22, it is stored at the bottom of the tower, extracted outside, cooled by a cooler, and then supplied again into the tower to come into gas-liquid contact with the combustion exhaust gas 22. . The cooling device 17 is not limited to a device that cools the combustion exhaust gas 22 by directly contacting the combustion exhaust gas 22 with the cooling water 30, and cools the combustion exhaust gas 22 by indirectly exchanging heat with the cooling water 30. You may do it.

The combustion exhaust gas 22 is cooled by the cooling device 17 and then supplied to the CO ₂ recovery device 18.

The CO ₂ recovery device 18 is for removing CO ₂ contained in the combustion exhaust gas 22. The CO ₂ recovery device 18 is provided downstream of the second heat exchanger 16 with respect to the flow direction of the combustion exhaust gas 22 in the combustion exhaust gas discharge line L12. As the CO ₂ recovery device 18, a conventionally known one can be used. CO The ₂ recovery device 18, for example, CO ₂ absorbs CO ₂ in the the CO ₂ absorbing solution of amine and the flue gas 22 by gas-liquid contact in a CO ₂ absorption combustion in fluid exhaust 22 tower absorption it can be used and towers, and the like apparatus and a regenerator which dissipates CO ₂ absorbed by the CO ₂ absorbing solution in the column to reproduce the CO ₂ absorbing liquid. The combustion exhaust gas 22 is contacted CO ₂ absorbing solution and gas-liquid in a CO ₂ absorption tower, CO ₂ in the combustion exhaust gas 22 is absorbed by the CO ₂ absorbing solution, the CO ₂ in the combustion exhaust gas 22 is removed. The combustion exhaust gas 22 is released into the atmosphere as a purified gas after the CO ₂ contained in the combustion exhaust gas 22 is removed by the CO ₂ recovery device 18.

  The raw material gas branch line L11 connects the downstream side of the desulfurization device 13 and the air supply line L15, and the natural gas 21 compressed by the compressor 11 is downstream of the desulfurization device 13 with respect to the flow direction of the natural gas 21. It is extracted from the side and mixed with the combustion exhaust gas 22 passing through the air supply line L15. Since the S content contained in the natural gas 21 is removed by the desulfurization device 13, the natural gas 21 not containing the S content can be supplied to the air supply line L15. As a result, the combustion exhaust gas 22 discharged from the reformer 14 does not contain S. As a result, the amount of S in the combustion exhaust gas 22 becomes extremely small, so that the acid dew point temperature itself is lowered. Accordingly, the exhaust gas temperature can be further lowered and the amount of heat recovered from the exhaust gas can be increased, so that the fuel in the reformer 14 can be reduced.

For example, the amount of natural gas 21 used as fuel in the reformer 14 can be reduced by, for example, about 0.7% to 8.5%.
That is, in the conventional methods for producing methanol and ammonia such as Patent Documents 1 and 2, when a part of natural gas that has not been desulfurized is generally extracted and used as a fuel for a reformer There are many. For this reason, when the amount of heat recovered from the combustion exhaust gas is increased and the temperature of the combustion exhaust gas is lowered, sulfuric acid corrosion is caused by sulfur content such as anhydrous sulfuric acid contained in the combustion exhaust gas in the pipe passage through which the combustion exhaust gas passes. It can happen. In sulfuric acid corrosion, the temperature of the flue gas becomes lower than the dew point temperature of the acid of S such as anhydrous sulfuric acid contained in the flue gas, and the sulfur contained in the flue gas combines with moisture and sulfuric acid (H ₂ SO ₄ ) Condensates and corrodes metal. Therefore, it is necessary to use acid-resistant steel having high corrosion resistance against acids such as sulfuric acid as a material for piping through which combustion exhaust gas passes. On the other hand, in this embodiment, since the flue gas 22 discharged from the primary reformer 14-1 does not contain S, the flue gas 22 exchanges heat with the combustion air 26 in the second heat exchanger 16. Even if the temperature of the combustion exhaust gas 22 decreases, corrosion occurs in the passage of the combustion exhaust gas exhaust line L12 on the downstream side in the gas flow direction of the combustion exhaust gas 22 from the second heat exchanger 16 of the combustion exhaust gas exhaust line L12. Can be suppressed. Therefore, the material of the combustion exhaust gas discharge line L12 is not limited to acid-resistant steel, and other materials can be used, and the application range can be expanded.

In addition, in the conventional methods for producing methanol and ammonia such as Patent Documents 1 and 2, in consideration of the possibility of sulfuric acid corrosion in the passage of the piping through which the combustion exhaust gas passes, The heat exchanger that exchanges heat with the gas cannot sufficiently recover the heat held in the combustion exhaust gas. Therefore, the operating cost of the plant equipment which manufactures methanol and ammonia becomes high, and the manufacturing cost of the product may increase. On the other hand, in this embodiment, even if the temperature of the combustion exhaust gas 22 is lowered by the second heat exchanger 16, it is possible to suppress the corrosion in the combustion exhaust gas discharge line L12, so that the combustion exhaust gas 22 is further cooled. It becomes possible to do. Therefore, more heat retained by the combustion exhaust gas 22 in the second heat exchanger 16 can be recovered by the combustion air 26, and the thermal efficiency of the reforming facility 10 can be improved.
Here, the heat exchange in the second heat exchanger 16 is, for example, 175 ° C. in consideration of the acid dew point, but can be lowered to the lower limit of 120 ° C. The lower limit of 120 ° C. is the exhaust gas temperature determined in consideration of the dew point of water.

  Further, when a denitration device 15 or the like is installed in the combustion exhaust gas discharge line L12, a reducing agent 29 such as ammonia is supplied into the flue, but methanol conventionally used as in Patent Documents 1 and 2, etc. In the process for producing ammonia, unreacted ammonia (also referred to as leaked ammonia) reacts with the S component to cause precipitation of ammonium sulfate, ammonium hydrogen sulfate, and the like. Ammonium sulfate may be deposited on heat transfer tubes and coils in a heat exchanger that exchanges heat between combustion exhaust gas and natural gas, and may block the pipe through which combustion exhaust gas passes to increase pressure loss. Ammonium hydrogen sulfate may cause corrosion in a heat exchanger that exchanges heat between combustion exhaust gas and natural gas, a material that forms a pipe through which the combustion exhaust gas passes, and the like. On the other hand, in the present embodiment, since there is no S component in the combustion exhaust gas 22 discharged from the reforming device 14, a reducing agent 29 such as ammonia is added to the combustion exhaust gas exhaust line L12 upstream of the denitration device 15. Even if it supplies in, it can suppress that reducing agent 29, such as unreacted ammonia, and S component react, and ammonium sulfate, ammonium hydrogen sulfate, etc. are produced | generated. Thereby, ammonium sulfate, ammonium hydrogen sulfate, and the like are deposited in the combustion exhaust gas discharge line L12 to suppress an increase in pressure loss in the combustion exhaust gas discharge line L12, corrosion in the passage of the combustion exhaust gas discharge line L12, and the like. Can do.

Further, in order to comply with environmental regulations and the like, a CO ₂ recovery device 18 is provided to remove CO ₂ contained in the combustion exhaust gas 22, which has been conventionally used as in Patent Documents 1 and 2, for example. In the method for producing methanol and ammonia, a desulfurization device is provided upstream of the CO ₂ recovery device in the gas flow direction of the combustion exhaust gas, and the sulfur concentration in the combustion exhaust gas at the inlet of the CO ₂ recovery device is set to a predetermined value (for example, 1 ppm). ) It is necessary to do the following. Moreover, the number of apparatuses to be installed increases as much as the desulfurization apparatus is provided, and the place where each apparatus is disposed is limited and the equipment cost increases. On the other hand, in this embodiment, since there is no S component in the combustion exhaust gas 22 discharged from the primary reformer 14-1, the upstream side in the gas flow direction of the combustion exhaust gas 22 from the CO ₂ recovery device 18. CO ₂ in the combustion exhaust gas 22 can be recovered without providing a desulfurization device. Therefore, the equipment cost required for recovering CO ₂ in the combustion exhaust gas 22 can be reduced.

According to the reforming facility of the present invention, the primary reformer 14-1 can be made compact when dealing with an increase in the amount of reformed gas produced and discharged from the primary reformer 14-1. Since there is no S component in the combustion exhaust gas 22, the equipment cost can be reduced without providing a desulfurization device upstream of the CO ₂ recovery device 18 in the gas flow direction of the combustion exhaust gas 22.

10 Reforming equipment 11 Compressor (first compression section)
12 1st heat exchanger (heat exchange part)
13 Desulfurization equipment (desulfurization section)
14 reformer (reformer)
14a body 14b catalyst reaction tube 14c burner 14-1 primary reformer 14-2 secondary reformer 15 denitration device (denitration part)
16 2nd heat exchanger (heat exchange part)
17 Cooling device 18 CO ₂ recovery unit (CO ₂ recovery unit)
21 Natural gas 22 Combustion exhaust gas 23 Reformed gas 24 Water vapor 26 Combustion air 50 Temperature raising means (heat exchanger)

Claims (5)

A primary reformer that supplies steam to the raw material gas and primary reforms the hydrocarbons in the raw material gas to either or both of H ₂ and CO and CO ₂ ;
Using the combustion air, the hydrocarbon in the reformed gas after the primary reforming in the primary reformer is secondarily reformed into one or both of H _2, CO and CO _2, and the reformed gas A secondary reformer and
And a temperature raising means interposed between the primary reformer and the secondary reformer for raising the temperature of the reformed gas after the primary reforming in the primary reformer. Quality equipment. In claim 1,
The reforming apparatus, wherein the temperature raising means is a heat exchanger using a high temperature reformed gas reformed by a secondary reformer. In claim 1,
The reforming apparatus, wherein the temperature raising means is a natural gas heater or an electric heater. In claim 3,
The reforming apparatus, wherein the temperature raising means is a combined use of either a natural gas heater or an electric heater and a heat exchanger. A first compression section for compressing a raw material gas containing hydrocarbon and sulfur;
A first heat exchange section for heating the compressed source gas;
A desulfurization section for removing sulfur contained in the heated raw material gas;
Wherein said hydrocarbon feed gas reformed in one or both of H ₂ and CO and CO _2, to produce a reformed gas containing one or both of H ₂ and CO and CO ₂ A reformer as claimed in any one of claims 1 to 4,
Combustion fuel used for heating in the reforming unit by extracting a part of the compressed source gas from either or both of the upstream side and the downstream side of the desulfurization unit with respect to the flow direction of the source gas As a raw material gas branch line,
A flue gas exhaust line that discharges flue gas generated by combustion in the reforming unit from the reforming unit;
A second heat exchange part that exchanges heat with the combustion exhaust gas heat-exchanged in the first heat exchange part for the combustion air used for heating in the reforming part,
The first heat exchange unit is provided in the combustion exhaust gas discharge line, and the combustion exhaust gas is used as a heating medium for the compressed source gas,
The second heat exchange part is provided on the downstream side of the first heat exchange part of the combustion exhaust gas discharge line, and is used as a heating medium for the combustion air by the residual heat exchanged in the first heat exchange part. Reforming equipment.

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