JP2761636B2 - Hydrocarbon steam reforming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for steam reforming of highly desulfurized hydrocarbons.

[0002]

2. Description of the Related Art A typical desulfurization method performed prior to steam reforming of hydrocarbons is to hydrocrack organic sulfur in hydrocarbons in the presence of a Ni-Mo or Co-Mo catalyst. Thereafter, the generated H ₂ S is adsorbed on ZnO and removed.

[0003] However, such a conventional method has many problems. That is, in the hydrodesulfurization step,
When hydrocarbons contain a certain amount or more of organic sulfur, especially insoluble organic sulfur such as thiophene, undecomposed substances slip and are not adsorbed by ZnO,
Pass through. In the case of adsorption desulfurization, for example,

[0004]

Embedded image

[0005] Due to the equilibrium shown in the above, the amount of H ₂ S, COS, etc., does not fall below a certain value. This is especially true when H ₂ O and CO ₂ are present. Further, when the desulfurization system is unstable at the time of starting up or shutting down the apparatus, sulfur may be scattered from the hydrodesulfurization apparatus and the adsorption desulfurization catalyst, and the sulfur concentration in the purified product may increase. Therefore, in the desulfurization step in the current steam reforming process, the sulfur concentration in the purified hydrocarbon is several vol.
It must be managed at a level such that it is in the range of ppm to 0.1 vol.ppm.

[0006] The hydrocarbon desulfurized as described above is
Next, it is subjected to steam reforming in the presence of a Ru-based or Ni-based catalyst. However, McCarty et al;
J. Chem. Phys. Vol 72.No.12.6332, 1980: J. Chem.Phys.
vol. 74, No.10.5877, 1981), Ni and Ru have a strong sulfur adsorption capacity, so even if the sulfur content in hydrocarbons is extremely small, the catalyst surface Is largely covered by sulfur. Specifically, under the general steam reforming process inlet conditions (around 450 ° C),
At the current best level of about 0.1 ppm sulfur, about 90% of the surface of Ni or Ru catalyst is
It will be covered in a short time. This means that the current level of hydrocarbon desulfurization cannot prevent sulfur poisoning of the catalyst in the steam reforming process.

In consideration of such problems, Japanese Patent Application Laid-Open No. Sho 62-170
No. 03 proposes a steam reforming method using a hydrocarbon desulfurized to 0.5 ppm or less. However, in the method described here, the degree of desulfurization of the hydrocarbon is insufficient, so that the poisoning of the steam reforming catalyst cannot be sufficiently prevented, and the use of steam is reduced as described later. Not done.

[0008]

SUMMARY OF THE INVENTION Accordingly, it is a main object of the present invention to effectively prevent sulfur poisoning of a steam reforming catalyst and extend the life of the catalyst.

[0009]

Means for Solving the Problems The present inventor has conducted intensive studies in view of the state of the art as described above, and as a result, has found that the sulfur content in hydrocarbons subjected to steam reforming is preferably 5 ppb or less, more preferably When it is set to a low level of 1 ppb or less, more preferably 0.1 ppb or less, it can not only substantially prevent sulfur poisoning of the steam reforming catalyst but also prevent carbon deposition on the catalyst. Was found.

[0010] That is, the present invention relates to a steam reforming method for hydrocarbons, which comprises desulfurizing a hydrocarbon to a sulfur content of 1 ppb or less with a high-order desulfurizing agent and then performing steam reforming.

In the present invention, the unit "ppb" indicating the sulfur concentration means vol.ppb (volume ppb).

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS It has been well known that sulfur poisoning is a major deterioration factor of a steam reforming catalyst. However, by setting the sulfur content in the hydrocarbon subjected to steam reforming to 5 ppb or less, more preferably 1 ppb or less, and even more preferably 0.1 ppb or less, not only sulfur poisoning but also carbon deposition is prevented. That is a new finding that was completely unexpected in the past. Therefore, according to the method of the present invention, in the steam reforming of hydrocarbons, the low steam ratio operation, the low hydrogen ratio operation, and the lamp which could not be adopted due to the deterioration of the activity due to the deposition of carbon on the catalyst and the restriction of the reactor were restricted. Operation using a heavy hydrocarbon feedstock such as a gas oil fraction becomes possible. As a result, the economy of the steam reforming process is greatly improved.

Hereinafter, the present invention will be described in more detail with reference to the flowcharts shown in the drawings.

FIG. 1 shows an embodiment of the method of the present invention using a hydrocarbon having a total sulfur compound content of 10 ppm or less (as sulfur: the same applies hereinafter) as a raw material. In this case, the raw material is subjected to a desulfurization step for reducing the sulfur content to 5 ppb or less, more preferably 1 ppb or less, and still more preferably 0.1 ppb or less (hereinafter referred to as higher desulfurization). In such high-order desulfurization, the sulfur content in the hydrocarbon is 5 ppb or less, preferably 1 ppb or less, more preferably 0.1 ppb or less.
Preferred examples of such a high-order desulfurization method include desulfurization methods using copper-zinc-based and copper-zinc-aluminum-based desulfurization agents disclosed in Japanese Patent Application Nos. 622-279867 and 62-279868. It is listed as. Such a desulfurizing agent is prepared by the following method.

(1) Copper-zinc desulfurizing agent An aqueous solution containing a copper compound (eg, copper nitrate, copper acetate, etc.) and a zinc compound (eg, zinc nitrate, zinc acetate, etc.) and an alkaline substance (eg, sodium carbonate, carbonate, etc.) Potassium, etc.)
Is precipitated by a conventional coprecipitation method using an aqueous solution of The resulting precipitate is dried and calcined at about 300 ° C. to obtain a copper oxide-zinc oxide mixture (generally copper: zinc:
= 1: about 0.3 to 10, preferably 1: about 0.5 to 3, more preferably 1: about 1 to 2.3), and the hydrogen content is 6% by volume or less,
More preferably, the mixture is reduced at about 150 to 300 ° C. in the presence of hydrogen gas diluted with an inert gas (for example, nitrogen gas or the like) so as to be about 0.5 to 4% by volume. The copper-zinc desulfurizing agent thus obtained may contain a certain metal oxide, for example, chromium oxide, as another carrier component.

(2) Copper-zinc-aluminum desulfurizing agents Copper compounds (eg, copper nitrate, copper acetate, etc.), zinc compounds (eg, zinc nitrate, zinc acetate, etc.) and aluminum compounds (eg, aluminum nitrate, aluminate) An aqueous solution containing sodium and the like and an aqueous solution of an alkaline substance (eg, sodium carbonate, potassium carbonate, etc.) are used to cause precipitation by a common coprecipitation method. The formed precipitate is dried and calcined at about 300 ° C. to obtain a copper oxide-zinc oxide-aluminum oxide mixture (generally copper: zinc: aluminum = 1: about 0.3-10: about 0.05-2, more preferably 1: About
0.6 to 3: After obtaining about 0.3 to 1), 150 to 150% in the presence of hydrogen gas diluted with an inert gas so that the hydrogen content becomes 6% by volume or less, more preferably about 0.5 to 4% by volume. The mixture is reduced at about 300 ° C. The copper-zinc-aluminum-based desulfurizing agent thus obtained may contain a certain metal oxide, for example, chromium oxide, as another carrier component.

The copper-based desulfurizing agent obtained by the methods (1) and (2) is characterized in that fine-particle copper having a large surface area is uniformly dispersed in zinc oxide (and aluminum oxide), It is in a highly active state due to chemical interaction with zinc (and aluminum oxide). Therefore, when using these desulfurizing agents, ensure that the sulfur content in hydrocarbons is 5 ppb or less and that appropriate conditions are selected.
It can be easily reduced to 1 ppb or less, more preferably 0.1 ppb or less under optimum conditions, and it is also possible to reliably remove hardly decomposable sulfur compounds such as thiophene. In particular, in the case of a copper-zinc-aluminum desulfurizing agent, there is obtained an advantage that due to the action of aluminum oxide, heat resistance is excellent, and a decrease in strength at high temperatures and a decrease in sulfur adsorption power can be remarkably reduced. Can be

Higher-order desulfurization using the above-mentioned copper-based desulfurizing agent is usually performed at a temperature of about 200 to 400 ° C., a pressure of about 1 to 50 kg / cm ² · G, GHSV
It is performed under the condition of about 1,000 to 5,000.

FIG. 2 shows an embodiment of the method of the present invention using a hydrocarbon having a total sulfur compound content of 10 ppm or more but a hardly decomposable organic sulfur compound content of less than 10 ppm as a raw material. In this case, first, the raw material hydrocarbon is, for example, Zn
It is subjected to primary adsorption desulfurization by a conventional method using an O-based desulfurizing agent. The conditions at this time are not particularly limited,
In order to maximize the sulfur compound adsorption effect in the subsequent high-order desulfurization process, the sulfur content in hydrocarbons should be 1 to 0.1 pp
It is desirable to keep it to about m. Therefore, in the primary adsorption desulfurization, in the presence of a ZnO-based desulfurization agent,
It is preferable to employ the conditions of about 0 ° C., the pressure of about 10 kg / cm ² · G, and the GHSV of about 1000, but other conditions can of course be employed. Next, the hydrocarbon having undergone the primary adsorption desulfurization is sent to the same high-order desulfurization step as described above, and the sulfur content is 5 ppb or less, preferably 1 ppb or less, more preferably 0.
After the pressure is reduced to 1 ppb or less, steam reforming is performed by an ordinary method.

FIG. 3 shows one embodiment of the method of the present invention using a hydrocarbon as a raw material having a total sulfur compound content of not less than 10 ppm, mainly a hardly decomposable organic sulfur compound. In this case, first, the raw material hydrocarbon is, for example,
Hydrodesulfurization is performed in the presence of a Ni-Mo or Co-Mo type catalyst at a temperature of about 350 to 400 ° C, a pressure of about 10 kg / cm ² · G, and a GHSV of about 3000. Next, after performing the same primary adsorptive desulfurization as described in connection with FIG. 2, high-order desulfurization is performed, and the sulfur content in the hydrocarbon is reduced to 5 ppb or less, preferably 1 ppb or less, more preferably 0.1 ppb or less. I do. At this time, since the hydrocarbon subjected to the adsorption desulfurization treatment is at a high temperature, the copper-
It is preferable to perform a high-order desulfurization using a zinc-aluminum-based desulfurizing agent. The highly desulfurized hydrocarbon is subjected to steam reforming by a conventional method.

The hydrocarbon used as a raw material in the present invention includes natural gas, ethane, propane, butane, LP
Examples include G (liquefied petroleum gas), light naphtha, heavy naphtha, light kerosene, coke oven gas, and various city gases.

[0022]

According to the present invention, the sulfur poisoning of the steam reforming catalyst and the deposition of carbon on the catalyst are extremely effectively prevented, so that the catalyst life is greatly extended. In addition, the required amount of water vapor can be reduced. That is, in the conventional steam reforming method, in order to perform a long-time operation, S / C
(Moles of water vapor per mole of carbon in hydrocarbons)
However, according to the method of the present invention, S / C
However, even with 0.7 to 3.5, stable operation can be performed for a long time.

[0023]

EXAMPLES Reference examples, examples and comparative examples are shown below to further clarify the features of the present invention.

REFERENCE EXAMPLE With the present measurement technique, directly measuring ppb order sulfur contained in a combustible substance such as a hydrocarbon is as follows.
Have difficulty. Therefore, in the present specification,
The measurement of the sulfur content on the order of ppb is a value calculated based on the following method.

The coke oven gas preliminarily purified by a conventional method was subjected to high-order desulfurization using a copper-zinc-aluminum desulfurizing agent disclosed in Japanese Patent Application No. 62-279868. The obtained high-order desulfurized coke oven gas was supplied at 5000 Nm ³ / hr at 2 wt.% Ru / Al ₂ O ₃ /
It is introduced into a reforming reactor (inner diameter: 160 cmφ) packed with 3.5 tons of catalyst (bulk density: 0.8 kg / liter).
The reforming reaction was performed for 6000 hours. The saturation poisoning amount of the catalyst used is about 0.002 gS / g-catalyst.

Ruthenium has a very high sulfur adsorption capacity,
If a small concentration of sulfur is present in the gas phase, it adsorbs immediately.
Therefore, sulfur is a very thin layer on the surface of the catalyst layer (10
(depth in cm).

Therefore, after the completion of the above reaction, sulfur was analyzed by X-ray fluorescence analysis on the surface layer up to 10 cm from the surface of the catalyst layer. As a result, it was below the detection limit of sulfur (0.00005 gS / g-catalyst) by the fluorescent X-ray analysis method. Therefore, the sulfur content in the high-order desulfurized raw material gas is:
It was calculated by the following equation and was found to be 0.1 ppb or less.

[0028]

(Equation 1)

When using LPG, naphtha and the like other than the coke oven gas, the sulfur content was calculated in the same manner.

Example 1 Naphtha having a sulfur content of 100 ppm was first prepared according to a conventional method.
Temperature 380 ° C, pressure 10kg / c in the presence of Ni-Mo type hydrodesulfurization catalyst
After hydrogenolysis under the conditions of m ² · G, LHSV2, hydrogen / naphtha = 0.1 (molar ratio), it was brought into contact with ZnO-based desulfurizing agent,
Primary adsorptive desulfurization. The sulfur concentration in the obtained primary adsorptive desulfurization naphtha was about 2 ppm.

On the other hand, sodium carbonate was added as an alkaline substance to a mixed aqueous solution in which copper nitrate, zinc nitrate and aluminum nitrate were dissolved, and the resulting precipitate was washed and filtered.
Tablet molding to a size of 1/8 inch height x 1/8 inch diameter,
It was fired at about 400 ° C. Next, the fired body (copper oxide 45%,
Filled with 100cc of zinc oxide 45%, aluminum oxide 10%)
A nitrogen gas containing 2% of hydrogen was passed through the desulfurization apparatus, and reduced at a temperature of about 200 ° C.
High-order desulfurization was performed at a temperature of 350 ° C. and a pressure of 8 kg / cm ² · G at a rate of 00 liter / hr. The sulfur concentration in the obtained higher-order desulfurized naphtha was below 0.1 ppb on average over 7,000 hours of operation.

Next, using the obtained high-order desulfurized naphtha as a raw material, using a flow-type pseudo-adiabatic reactor (diameter 20 mm), a ruthenium catalyst (ruthenium 2w on a γ-alumina carrier) was used.
% was carried out under the conditions shown in Table 1 to produce methane.

Table 1 Reaction temperature (inlet) 490 ° C (adiabatic) Reaction pressure 8 kg / cm ² · G Naphtha flow rate 160 cc / hr Catalyst amount 100 cc S / C 1.7 H ₂ / naphtha 0.1 (molar ratio) The results are shown. In FIG. 4, curve A-1 shows the temperature profile of the catalyst layer in the reactor immediately after the start of the reaction, and curve A-2 shows the temperature profile of the catalyst layer in the reactor 400 hours after the start of the reaction.

According to the method of the present invention, the reforming catalyst continues to maintain a sufficiently high activity even after the elapse of 400 hours. The temperature decreases due to decomposition, and the temperature increases due to the subsequent exothermic reactions such as methanation and CO denaturation.

Such a highly active state of the reforming catalyst depends on the amount of carbon deposited at each position on the catalyst after 400 hours (0.4 wt.% Or less only at the reactor inlet) and the amount of sulfur deposited (at the reactor inlet). Below the detection limit of X-ray fluorescence analysis). Therefore, according to the present invention, a large amount of hydrogen or steam for preventing carbon deposition is not required, the consumption of the reforming catalyst is greatly reduced, the required amount of the catalyst is also reduced, and the reactor can be downsized. It becomes possible.

Comparative Example 1 Naphtha having a sulfur content of 100 ppm was first prepared according to a conventional method.
Temperature 380 ° C, pressure 10kg / c in the presence of Ni-Mo type hydrodesulfurization catalyst
After hydrogenolysis under the conditions of m ² · G, LHSV = 2, hydrogen / naphtha = 0.1 (molar ratio), it was brought into contact with ZnO-based desulfurizing agent,
Primary adsorptive desulfurization. The sulfur concentration in the obtained primary desulfurized naphtha was about 2 ppmm.

The primary desulfurized naphtha thus obtained was subjected to steam reforming in the same manner as in Example 1.

The results are as shown in FIG. In FIG. 5, curve B-1 shows the temperature profile of the catalyst layer in the reactor immediately after the start of the reaction, and curve B-2 shows the temperature profile of the catalyst layer in the reactor 200 hours after the start of the reaction.

As is apparent from the curve B-1, immediately after the start of the reaction, since the reforming catalyst has sufficient activity, naphtha, which is an endothermic reaction, is decomposed at the inlet of the catalyst layer, and the temperature decreases. The temperature rises due to the subsequent exothermic reactions such as methanation reaction and CO denaturation reaction.

On the other hand, as is apparent from the curve B-2, 2
After the lapse of 00 hours, the reforming catalyst is almost completely deactivated, no temperature change of the catalyst layer due to endothermic reaction and exothermic reaction is observed, and the primary desulfurized naphtha exits the reforming reactor without reacting. come.

The deactivated state of such a reforming catalyst is represented by a curve B-3 showing the amount of carbon deposited (% based on the catalyst weight) at each position on the catalyst after 200 hours, and the amount of sulfur deposited (% based on the catalyst weight). ) Is also supported by curve B-4.

Such a large amount of carbon deposition not only blocks the pores of the catalyst and causes a decrease in the catalytic activity, but also causes the powdering of the catalyst, the clogging of the reactor and the increase in the differential pressure. Also. Therefore, in order to perform long-time operation,
This is a matter to be prevented as much as possible, and generally, a large amount of water vapor or hydrogen is used to prevent it.

Example 2 A steam reforming catalyst similar to that used in Example 1 was used for steam reforming as in Example 1 without prior sulfur poisoning or poisoning. Details of each catalyst are as follows.

Catalyst I: No sulfur poisoning Catalyst II: Sulfur adhesion amount 0.05 wt.% Catalyst III: Sulfur adhesion amount 0.2 wt.% The results are shown in FIG. When catalyst I was used, almost no carbon deposition was observed even after 300 hours, whereas in the case of catalysts II and III, a large amount of carbon was precipitated. This demonstrates that the attachment of small amounts of sulfur to the catalyst promotes carbon deposition. Therefore, the present invention, in which steam is reformed after performing higher-order desulfurization of hydrocarbons, effectively prevents carbon deposition on the catalyst, and greatly contributes to extending the life of the reforming catalyst. .

Example 3 Naphtha subjected to high-order desulfurization adsorption in the same manner as in Example 1 was used as a raw material, and steam reforming was performed in the same manner as in Example 1 except that the S / C was changed in various ways. The relationship between the amount of carbon deposited on the Ru-based catalyst at the reactor inlet and the S / C is shown as curve C in FIG.

As is apparent from FIG. 7, when naphtha which has been subjected to higher desulfurization is used as a raw material, carbon deposition on the catalyst does not substantially occur even if the S / C is reduced to about 0.7. .

On the other hand, when the primary desulfurized naphtha obtained in the same manner as in Comparative Example 1 is used as a raw material and steam reforming is performed under the same conditions, in order to achieve the same effect of preventing carbon deposition as described above, the initial operation is performed. It is necessary to set the S / C to 1.5 or more even in the case of
C had to be 2.5 or more.

Example 4 The same procedure as in Example 3 was repeated except that the most common Ni-based catalyst (produced by the coprecipitation method, NiO concentration 50 wt.%) Was used as a steam reforming catalyst. Modification was performed.
The relationship between the amount of carbon deposited on the Ni-based catalyst at the reactor inlet and the S / C is shown as curve D in FIG.

S / C required to stably suppress carbon deposition
The value of = 1.5 is higher than when a highly active Ru-based catalyst is used. However, compared with S / C = 2 or more (initial operation) required when using the primary adsorptive desulfurization naphtha obtained in the same manner as in Comparative Example 1 as a raw material, it is much lower and more stable for a long period of time. S / necessary for driving
It is much lower than C = 3.5 or more.

Example 5 A high-order desulfurized purified naphtha obtained in the same manner as in Example 1 and a primary desulfurized purified naphtha obtained in the same manner as in Comparative Example 1 were used as raw materials, respectively, and the same Ru as in Example 1 was used. High temperature steam reforming of naphtha was carried out under the conditions shown in Table 2 using an externally heated reactor (1.5 inch in diameter) filled with a system catalyst.

In the case of using a primary desulfurized purified naphtha containing 2 ppm of sulfur as a raw material, the activity of the catalyst is lost after 200 hours, and almost all of the naphtha has come out of the reactor without being reacted. Then, a differential pressure began to occur in the catalyst layer. Further, precipitation of a large amount of carbon as much as 20 wt.% Or more was observed on the catalyst near the reactor inlet.

On the other hand, when the high-desulfurized purified naphtha was used as a raw material, no activity degradation phenomenon such as naphtha slip was observed even after 400 hours, and no carbon deposition on the catalyst was observed.

Table 2 Reaction temperature Inlet: 400 ° C. Outlet: 700 ° C. Reaction pressure 8 kg / cm ² · GS / C 2.0 H ₂ / naphtha 0.1 (molar ratio) LHSV 1.2 Catalyst amount 100 cc Example 6 Same as Example 5 High temperature steam reforming of naphtha was performed under the conditions shown in Table 3.

In the case of using high-order desulfurized purified naphtha as a raw material, no phenomena of activity deterioration such as naphtha slip were observed even after lapse of 2,000 hours, and no carbon deposition on the catalyst was observed.

On the other hand, when the primary desulfurized purified naphtha (sulfur content: 0.1 ppm) desulfurized in the same manner as in Comparative Example 1 except that the LHSV at the time of hydrodesulfurization was set to 1 was used as a raw material, In addition, the pressure difference in the catalyst layer increased, and the operation became impossible. At this time, a large amount of unreacted naphtha came out of the reactor. When the catalyst thus used was analyzed, carbon deposition of 10 to 20 wt.% Was observed.

Table 3 Reaction temperature Inlet: 400 ° C. Outlet: 745 ° C. Reaction pressure 8 kg / cm ² · GS / C 2.0 H ₂ / naphtha 0.1 (molar ratio) LHSV 2.0 Catalyst amount 100 cc Example 7 Same as Example 1 And a primary desulfurized purified naphtha obtained in the same manner as in Comparative Example 1 were used as raw materials, respectively, and a flow type pseudo adiabatic reactor (diameter 20 mm) was used.
Was used to perform steam reforming under the conditions shown in Table 4 in the presence of the commercially available Ni catalyst used in Example 4.

Table 4 Reaction temperature Inlet: 490 ° C. (adiabatic) Reaction pressure 8 kg / cm ² · G Naphtha flow rate 160 cc / hr Catalyst amount 100 cc S / C 2.5 H ₂ / naphtha 0.1 (molar ratio) FIG. 8 and FIG. The results are shown.

In FIG. 8, the curves E-1 and E-2 are
The temperature profiles of the catalyst layer in the reactor immediately after the start of the reaction and 400 hours after the start of the reaction are shown. When using a high-order desulfurized purified naphtha, the same as in Example 1, 400
After time, the temperature profile does not change and the reforming catalyst continues to maintain a sufficiently high activity. Therefore, according to the present invention, even when a Ni catalyst is used, a large amount of hydrogen or steam as conventionally used for preventing carbon deposition is not required, and the consumption of the reforming catalyst can be reduced and required. It is possible to reduce the size of the reactor by reducing the amount of the catalyst.

On the other hand, the result when primary desulfurized naphtha is used is as shown in FIG. In FIG. 9, the curve F-1
And curve F-2 show the reaction immediately after the start of the reaction and 400
4 shows the temperature profile of the catalyst layer in the reactor after time.

As is clear from the comparison between the curves F-1 and F-2, after 400 hours, the reforming catalyst near the reactor inlet has been deactivated, and the temperature change due to the endothermic reaction and the exothermic reaction has occurred. The region is moving in the direction of the outlet of the catalyst layer. Further, at this time, a large amount of carbon of 10 wt.% Or more was precipitated, and it was impossible to continue the operation any more due to an increase in the differential pressure.

Example 8 An external heat reactor filled with a commercially available Ni catalyst (Ni concentration 14 wt.%, Steam reforming catalyst for natural gas) using a high-order desulfurized purified naphtha obtained in the same manner as in Example 1 as a raw material (1.5 inch pipe diameter), naphtha was subjected to high-temperature steam reforming under the conditions shown in Table 5. As a result, even after 600 hours, no activity deterioration phenomenon such as naphtha slip occurred, and no carbon deposition on the catalyst was observed.

Table 5 Reaction temperature Inlet: 490 ° C. Outlet: 750 ° C. Reaction pressure 8 kg / cm ² · GS / C 2.5 H ₂ / naphtha 0.1 (molar ratio) LHSV 1.0 Catalyst amount 300 cc Example 9 Coke with a sulfur content of 200 ppm Furnace gas, according to the usual method,
First, at a temperature of 380 ° C and a pressure of 8k in the presence of a Ni-Mo-based hydrodesulfurization catalyst
After hydrogenolysis under the conditions of g / cm ² · G and GHSV100, it was brought into contact with a ZnO-based adsorptive desulfurizer to perform primary adsorptive desulfurization. The concentration of sulfur compounds in the obtained primary adsorption desulfurization coke oven gas is about 0.
It was 1 ppm.

On the other hand, sodium carbonate was added as an alkaline substance to a mixed aqueous solution in which copper nitrate and zinc nitrate were dissolved, and the resulting precipitate was washed and filtered.
It was tableted to a size of / 8 inch and fired at about 300 ° C.
Next, 100 cc of the fired body (copper oxide 50%, zinc oxide 50%)
Hydrogen in a high-order desulfurization unit (desulfurization layer length 30 cm) filled with hydrogen
% At a temperature of about 200 ° C through nitrogen gas containing
Primary adsorption desulfurization coke oven gas obtained above 400 liter / hr
, High-order desulfurization was performed under the conditions of a temperature of 250 ° C and a pressure of 8 kg / cm ² · G.

As a result, the sulfur concentration in the purified gas finally obtained was 0.1 ppb or less over 10,000 hours of operation.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an embodiment of the present invention.

FIG. 2 is a flowchart showing another embodiment of the present invention.

FIG. 3 is a flowchart showing still another embodiment of the present invention.

FIG. 4 is a graph showing the effect of the degree of hydrocarbon purification on steam reforming.

FIG. 5 is a graph showing the effect of hydrocarbon purification on steam reforming.

FIG. 6 is a graph showing the change over time in the amount of carbon deposited during a steam reforming reaction in catalysts having different degrees of sulfur poisoning.

FIG. 7 is a graph showing the relationship between S / C (molar number of steam per mole of carbon in hydrocarbon) and the amount of carbon deposited on a catalyst in high-temperature steam reforming.

FIG. 8 is another graph showing the effect of the degree of hydrocarbon purification on steam reforming.

FIG. 9 is yet another graph showing the effect of hydrocarbon purification on steam reforming.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10G 35/04 C10G 35/04 61/06 61/06 (72) Inventor Ritsugu Mori 4-chome, Hirano-cho, Chuo-ku, Osaka-shi, Osaka No. 2 Inside Osaka Gas Co., Ltd. (72) Hiroki Fujita, Inventor 4-1-2 Hirano-cho, Chuo-ku, Osaka-shi, Osaka Prefecture In-house Osaka Gas Co., Ltd. (72) Naoko Fukumura, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Inside Osaka Gas Co., Ltd. (72) Inventor Masamichi Ipponmatsu Inside Osaka Gas Co., Ltd. 4-1-2 Hirano-cho, Chuo-ku, Osaka-shi, Osaka

Claims (3)

(57) [Claims] Claims: 1. A hydrocarbon desulfurizing agent is used to reduce the sulfur content of a hydrocarbon.
A steam reforming method for hydrocarbons, wherein desulfurization is performed to 1 vol.ppb or less, followed by steam reforming. 2. The method for steam reforming hydrocarbon according to claim 1, wherein steam reforming is performed after desulfurizing the sulfur content of the hydrocarbon to 0.1 ppb or less. 3. The carbonization according to claim 1, wherein the steam reforming is carried out under the condition of S / C (molar number of steam per mole of carbon in hydrocarbon) = 0.7 to 3.5. Hydrogen steam reforming method.