JP3813646B2 - Method for producing steam reforming catalyst and method for producing hydrogen - Google Patents

Description

【００７０】
【表２】

【００７１】
【表３】

【００７２】
【表４】

【００７３】
【表５】

【００７４】
図２および表１〜表５から明らかなように、灯油等の液状炭化水素を原料とする水蒸気改質による水素製造において、従来から一般に用いられている担持ニッケル系触媒Ｈ（比較例１）では、従来の一般的な反応条件と比べて、原料炭化水素の炭素数が高く、またＳ／Ｃ比が低い本実施例の反応条件は、触媒にとって過酷であるため、炭素析出等による触媒性能の著しい劣化が起こることが分かる。
【００７５】
また、耐炭素析出性に優れる担持ルテニウム系触媒であっても、第三成分を含まない触媒Ｉ（比較例２）を用いた場合では、原料液状炭化水素中に含まれる硫黄化合物によって触媒が被毒され、徐々に転化率の低下が起こるほか、被毒による二次的阻害として触媒上での炭素析出が生じ、反応中期からの活性劣化が著しくなることが分かる。
【００７６】
これらに対し、本発明の製造方法により得られる触媒Ａ〜Ｇ（実施例１〜７）を用いると、灯油等の液状炭化水素を原料とした場合でも、平衡転化率に近い充分な触媒活性が得られるばかりでなく、原料中の硫黄化合物による触媒被毒や触媒上の炭素析出という問題が起こり難いので、長期間安定した触媒性能を保つことができることが分かる。
【００７７】
【発明の効果】
本発明の水蒸気改質触媒の製造方法および水素製造方法を採用すれば、灯油等を原料として低Ｓ／Ｃ比の条件で長期間に亘り安定した水蒸気改質反応を行わせることができるため、ＣＯ，ＣＯ₂等を一部含有する水素ガスを収率良く、安価に製造することが可能である。
【図面の簡単な説明】
【図１】本発明の実施例および比較例で使用した水蒸気改質装置の概略を示すフロー図である。
【図２】本発明の実施例および比較例で得られた結果を示すグラフである。[0001]
[Industrial application fields]
  The present invention relates to a steam reforming catalyst.Manufacturing methodAnd theObtained by manufacturing methodThe present invention relates to a hydrogen production method using a catalyst, and more particularly, a catalyst used for producing hydrogen by steam reforming a low-cost liquid hydrocarbon.Manufacturing method,And theObtained by manufacturing methodThe present invention relates to a method for producing hydrogen using a catalyst.
[0002]
[Background Art and Problems to be Solved by the Invention]
As a method for producing hydrogen from a hydrocarbon as a raw material, (1) a non-catalytic partial oxidation method using oxygen or air as a gasifying agent and (2) a steam reforming method using steam are known.
[0003]
The former is not limited in terms of raw materials, but the production cost is low because of the need to use oxygen, the large power consumption (power consumption per unit of product), and the increased equipment costs. It has the disadvantage of being expensive. On the other hand, the latter is the most economical method for producing hydrogen at the present time because it does not use oxygen, and its power consumption and equipment costs are relatively low.
[0004]
In the conventional steam reforming method, the catalyst used is a nickel-based catalyst, and the raw material hydrocarbon is usually limited from natural gas to naphtha.
[0005]
By the way, hydrogen can be used for various purposes such as hydrodesulfurization, indirect desulfurization, direct desulfurization, aromatic solvent extraction, naphtha cracking separation, and benzene plant only in the fields of petroleum refining and petrochemistry. There are other uses such as CO production and various reductions.
In recent years, research and development of carbon dioxide fixation and resource recycling has been actively conducted from the viewpoint of global environmental conservation and resource reuse, and the key to this research and development is low-cost production of hydrogen. It is said.
[0006]
Therefore, lowering the hydrogen production cost not only has an economic effect on the chemical industry, but also has other effects on the development of environmental protection applied technology.
[0007]
In order to produce hydrogen economically, it is sufficient to use low-cost liquid hydrocarbons such as kerosene as the hydrocarbon source, but carbon deposition on the catalyst is conspicuous as the molecular weight of the raw material hydrocarbons increases. It becomes.
[0008]
Even with conventional nickel-based catalysts using alumina as a carrier, studies on the suppression of carbon deposition have been conducted.
For example, according to Japanese Patent Laid-Open No. 50-18378, a method of adding a small amount of rare earth as an active auxiliary component is proposed, but usable hydrocarbons are light fractions from methane to butane, such as naphtha, kerosene. It is difficult to use liquid hydrocarbons such as
Even if it is used, in order to suppress carbon deposition, the water vapor / carbon ratio (hereinafter abbreviated as S / C ratio) represented by the following formula must be set to be considerably high, and the operation is complicated. In addition, since the water vapor intensity increases, the advantage of the use of liquid hydrocarbons, such as kerosene, which is economical, is offset.
[0009]
[Expression 2]
S / C ratio = (number of moles of steam supplied to the reactor) / {number of moles of hydrocarbon (CnHm) supplied to the reactor × n}
[0010]
As described above, the nickel-based catalyst that has been widely used has a limit in the number of carbons of the raw material hydrocarbon that can be used.
For these reasons, it is said that it is extremely difficult to put into practical use a hydrogen production method by a steam reforming method using a liquid hydrocarbon such as kerosene as a raw material.
[0011]
On the other hand, a ruthenium-based catalyst has attracted attention because it has a carbon deposition suppressing effect and can perform a steam reforming reaction under a condition of an S / C ratio smaller than that of a nickel-based catalyst.
Examples of such ruthenium-based catalysts include those in which ruthenium is supported on alumina (for example, Kasaoka et al. “Fuel Association”, Vol. 59, page 25 (1980), Okada et al., “Catalyst” vol. 35, page 224 (1993)). Using a carrier obtained by adding cerium oxide to an alkali metal oxide or alkaline earth metal oxide (JP-A-4-265156), using zirconia as a carrier (JP-A-2-302304, No. 2-286787), and a ruthenium precursor using an alkali salt such as sodium ruthenate (Japanese Patent Laid-Open No. 60-227834).
[0012]
However, ruthenium-based catalysts are not only easily poisoned by sulfur contained in the raw material, but also have the disadvantage that sulfur poisoning triggers carbon deposition (for example, Okada et al. “Fuel Association Journal, Vol. 68, 39 (1989)).
As described above, even if the ruthenium catalyst has a carbon deposition inhibitory property, if poisoning due to the sulfur content in the raw material occurs, the maximum advantage of the ruthenium catalyst is impaired, which is extremely problematic in practical use.
[0013]
Sulfur content in the light fraction can be almost removed in the desulfurization process, so it is not a problem. However, liquid hydrocarbons such as kerosene contain difficult-to-desulfurize sulfur compounds, so it is difficult to eliminate the sulfur content.
Therefore, a steam reforming catalyst using these as a raw material is strongly required to have both sulfur poisoning resistance and carbon deposition inhibiting properties.
[0014]
As described above, in the conventional hydrogen production technology, as long as liquid hydrocarbon is used as a raw material, there remains a big problem of how to suppress carbon deposition.
In addition to the raw material hydrocarbon, it is the S / C ratio that affects the cost increase in hydrogen production.
Therefore, in order to suppress the increase in water vapor intensity, it is required to strongly suppress carbon deposition under the current S / C ratio condition, and also to have excellent sulfur poisoning resistance of the catalyst.
[0015]
In order to satisfy these requirements, it is impossible with known catalysts such as the above-described nickel catalyst system, and it is difficult to cope with these problems with some improvements.
In order to satisfy all of the above requirements, a catalyst having excellent carbon deposition inhibitory properties and sulfur poisoning resistance, specifically, a carrier having sufficient strength, a highly dispersed support of active metal, and high temperatures. There is a need for a catalyst that can suppress sintering during this reaction, but so far, such a catalyst is hardly found.
[0016]
  Therefore, the present invention is a catalyst in which carbon is difficult to deposit, catalyst performance is hardly deteriorated even when deposited, and a catalyst that does not cause a decrease in activity even if a sulfur content remains to some extent in the raw material, that is, carbon deposition inhibiting property, carbon resistance Steam reforming catalyst that has precipitation and sulfur poisoning resistance and enables long-term continuous reactionManufacturing methodAnd thisObtained by the production method ofAn object of the present invention is to provide a method for producing hydrogen from liquid hydrocarbons at low market prices such as kerosene using benzene.
[0017]
[Means for Solving the Problems]
  As a result of investigations to achieve the above-mentioned object, the present inventors have found that (1) Group II metal (hereinafter referred to as “Group 2 metal”) and Group III metal (hereinafter referred to as “Group 3”) of the periodic table. And a carrier obtained by calcining alumina containing a specific amount of at least one selected from the group consisting of oxides of lanthanoid metal and a lanthanoid metal oxide at a specific high temperature to carry a predetermined amount of ruthenium in a highly dispersed manner. Or (2) at least one selected from the group consisting of the oxides of Group 2, Group 3, and Lanthanoid metals is cerium, and a predetermined amount so as to be a specific amount in relation to cerium. When using a catalyst in which ruthenium is highly dispersed and supported, when a steam reforming reaction is performed using a liquid hydrocarbon such as kerosene as a raw material and an S / C ratio of 3 to 10 which is equivalent to the conventional level, Sulfurized Found that things catalyst be left somewhat difficult to be poisoned, carbon deposition on the catalyst is suppressed,like thisSteam reforming catalystHow to manufactureAnd theObtained by manufacturing methodA hydrogen production method using a catalyst has been completed.
[0018]
  That is, the steam reforming catalyst of the present inventionManufacturing methodIs an alumina containing 3 to 30 wt% of at least one selected from the group consisting of Group 2 metal, Group 3 metal and lanthanoid metal oxides (hereinafter sometimes referred to as “third component”) based on the catalyst. Obtained by baking at 800-900 ° CObtaining a carrier,Ruthenium on the carrierChloride aqueous solutionTheRuthenium0.5-5% by weightTo beCarryingThe ruthenium chloride is converted into a hydroxide to insolubilize and fix the ruthenium,Reduction treatment at 600 to 950 ° C. and carbon monoxide adsorption amount of 1.5 ml / g (standard state conversion, hereinafter referred to as “STP”) or moreSteam reforming catalystTheTo getFeatures.
  When the third component is cerium, rutheniumThe, 0.5-5% by weight supported so that the atomic ratio of cerium and ruthenium is less than 10LettingIs preferred.
[0019]
  Further, the hydrogen production method of the present invention comprises the above-mentioned raw material consisting of a liquid hydrocarbon having a sulfur content of 0.2 ppm or less, an aromatic compound content of 30% by volume or less, and a carbon number of 6 or more, and steam.Obtained by manufacturing methodContact with steam reforming catalyst, S / C ratio 3-10, LHSV 5h^-1Hereinafter, the reaction pressure is maintained at 2 atm or more.
[0020]
Among the third components constituting the catalyst carrier (composite carrier) of the present invention, as the Group 2 metal oxide, beryllium, magnesium, calcium, strontium, barium, radium oxides may be used alone or in combination of two or more. However, it is particularly preferable to use magnesium or barium oxide alone or in combination.
As group 3 metal oxides, oxides such as scandium and yttrium can be used alone or in admixture of two or more, and it is particularly preferable to use yttrium oxide.
As lanthanoid metal oxides, oxides such as lanthanum, cerium, praseodymium, neodymium, promethium, samarium can be used alone or in combination of two or more, and in particular, lanthanum and cerium oxides can be used alone or in combination. It is good to use.
[0021]
As the Group 2 metal oxide, Group 3 metal oxide, and lanthanoid metal oxide, the above oxides can be used as they are, and metal salts such as chlorides and nitrates can also be used as precursors.
[0022]
As alumina constituting the carrier of the catalyst of the present invention together with the third component, aluminum oxide can be used as it is.
In addition to this, an alkaline buffer solution having a pH of about 8 to 10 may be added to aluminum nitrate to form a hydroxide precipitate, which may be baked, or may be baked aluminum chloride. Also good.
In addition, sol-gel is prepared by dissolving an alkoxide such as aluminum isopropoxide in an alcohol such as 2-propanol, adding an inorganic acid such as hydrochloric acid as a catalyst for hydrolysis to prepare an alumina gel, and drying and firing the gel. What was prepared by the method can also be used.
Thus, metal salts, organometallic compounds, and the like can be preferably used for the alumina precursor.
[0023]
The content of the third component in the carrier is 3 to 30% by weight based on the catalyst.
When the content of the third component is less than 3% by weight, a sufficient improvement effect with respect to the sulfur poisoning resistance cannot be obtained, and therefore a sufficient life extension of the catalyst cannot be expected.
In other words, the mechanism of the development of sulfur poisoning resistance is presumed to be in the process of sulfur compounds in the raw material being adsorbed and absorbed by the third component, which makes the active ingredient ruthenium less susceptible to sulfur poisoning, Life expectancy will be extended.
On the other hand, if the content is more than 30% by weight, not only the raw material cost increases, but the amount of alumina relatively decreases, so that the mechanical strength is inferior and a composite of alumina and a third component (probably (Complex oxide) is remarkably generated, and the specific surface area is reduced.
Moreover, 5 to 25 weight% is preferable from a viewpoint of mechanical strength, and 5 to 20 weight% which maximizes mechanical strength without impairing sulfur poisoning resistance is particularly preferable.
[0024]
The support is prepared by dispersing and kneading the above-mentioned metal oxide in a solvent such as water, methanol, ethanol, acetone, etc., and then drying or firing it, or using a metal salt such as chloride or nitrate as a precursor in an appropriate solvent. The co-precipitate is produced by adjusting the pH of the mixed solution dissolved in the solution, and can be prepared by a method such as drying and baking.
[0025]
In addition, when using 2 or more types of metal oxides chosen from the group which consists of a group 2 metal, a group 3 metal, and a lanthanoid metal, the mixing order of these metal oxides or a precursor is not specifically limited.
For example, an aluminum compound and a Group 2 metal oxide are mixed and mixed with a Group 3 metal oxide and / or a lanthanoid metal oxide, or an aluminum compound and a lanthanoid metal oxide are mixed with the Group 2 metal oxide. An oxide and / or a Group 3 metal oxide may be mixed.
[0026]
As a method for molding the carrier, a known method such as a tableting molding method can be used, and a Raschig ring shape, a columnar shape, a spherical shape, or the like can be adopted as the shape.
[0027]
The carrier is desirably baked at 800 to 900 ° C.
When the calcination temperature is lower than 800 ° C., the temperature of the steam reforming reaction (hereinafter sometimes simply referred to as “reaction”) exceeds the calcination temperature. Effects such as lowering and deterioration of the dispersibility of the active metal (ruthenium) appear.
Conversely, when the firing temperature exceeds 900 ° C., composite oxides are formed between the carrier components, or the transition of the aluminum oxide crystals to the α phase (trigonal lees) takes place, improving the mechanical strength. Although it can be achieved, the specific surface area is significantly reduced, so that a predetermined amount of active metal cannot be supported.
That is, if it bakes at 800-900 degreeC, desired intensity | strength will be obtained.
Moreover, 850-900 degreeC is preferable from the meaning which suppresses the thermal history in a reforming reaction as much as possible, and the meaning which improves intensity | strength, and has the highest intensity | strength in the range which does not change to the alpha phase of an alumina, and receives thermal history. It is particularly preferable to fire at around 900 ° C., which is difficult.
[0028]
  As a method of loading ruthenium on the carrier,LaterUse the method.
[0029]
As ruthenium, precursors such as ruthenium trichloride anhydride, ruthenium trichloride hydrate, ruthenium nitrate can be used, but ruthenium trichloride monohydrate is used from the viewpoint of solubility and ease of handling. Particularly preferred.
[0030]
The supported amount of ruthenium is 0.5 to 5% by weight.
When the supported amount is less than 0.5% by weight, the number of active sites becomes too small, and when it is more than 5% by weight, there is not much improvement in activity commensurate with the increase, and the dispersibility of ruthenium Incurs a decline.
The range in which the dispersibility and the number of active sites are the highest is most preferably 0.5 to 3% by weight.
[0031]
By the way, when cerium is used as the third component, the atomic ratio of cerium to ruthenium (hereinafter sometimes referred to as “Ce / Ru ratio”) is less than 10, preferably 2 to 9.9. is important.
When the Ce / Ru ratio is extremely small, in other words, when the amount of cerium with respect to ruthenium is extremely small, the adsorption and absorption of sulfur in the raw material by these becomes insufficient, and ruthenium is poisoned by the remaining sulfur. Alternatively, carbon is deposited on the catalyst.
On the other hand, when the Ce / Ru ratio is 10 or more, ruthenium becomes too small relative to cerium, and it becomes difficult to maintain sufficient reaction activity for a long time.
[0032]
A method for supporting ruthenium on a carrier will be described with an example.
First, as a preparatory step, the carrier is weighed, pure water is dropped from the burette, the inside of the carrier is sufficiently hydrated, and the saturated moisture content is measured. In this operation, it is important that the carrier is sufficiently hydrated.
Next, an aqueous solution of ruthenium chloride monohydrate is prepared so that a predetermined amount of ruthenium is contained in the same amount of pure water as the measured saturated water content, and the aqueous solution is absorbed by the carrier by the saturated water content.
Thereafter, 5-10N ammonia water is dropped on the carrier so as to be in a large excess amount with respect to the supported ruthenium concentration, and ruthenium chloride is converted into a hydroxide as shown in the following formula, so that ruthenium is insoluble and immobilized. .
[0033]
[Chemical 1]
RuCl₃+ 3NH₄OH → Ru (OH)₃+ 3NH₄Cl
[0034]
At this time, as shown in Chemical formula 1, since the chlorine anion is in the form of water-soluble ammonium chloride, dechlorination can be effectively performed during the washing process.
[0035]
The carrier on which ruthenium is immobilized is preferably dried at as low a temperature as possible, and is preferably dried at a temperature of less than 200 ° C., more preferably less than 150 ° C., particularly preferably 100 ° C. or less, and reduced pressure or atmospheric pressure.
If the temperature is too high, a part of the hydroxide becomes an oxide, so that the oxidation state may not be uniform during the reduction treatment, and the dispersibility of ruthenium may be lowered. From this point, it is desirable to avoid the formation of oxides during drying as much as possible.
However, if the drying temperature is extremely low, the drying time becomes very long.
[0036]
For ruthenium insolubilization / immobilization, ammonia water can be used as described above, but in addition, an aqueous solution of a base such as sodium hydrogen carbonate, sodium carbonate, sodium hydroxide, potassium hydroxide or the like can be used. it can.
However, in these alkali salts, there is a possibility that alkali metal cations may remain, and therefore ammonia water is the easiest to handle.
[0037]
Although the reduction of the supported ruthenium occurs even at 600 ° C. or lower, it is preferably performed at 600 to 950 ° C. in order to suppress ruthenium sintering as much as possible during the steam reforming reaction and maintain stable catalytic activity.
In addition, it is more preferable to perform the reduction at 700 to 900 ° C. because stable catalytic activity is easily maintained when the reduction is performed in a region as close to the reaction temperature as possible and below the calcination temperature of the support.
Furthermore, when the supported ruthenium is oxidized for some reason after catalyst preparation, it is particularly preferable to perform the reduction at 800 to 900 ° C. because ruthenium oxide is difficult to reduce.
[0038]
Although the supported ruthenium is reduced even at 600 ° C. or lower, since the steam reforming temperature is higher than the reduction temperature, the catalyst is subjected to a thermal history under the reaction conditions, mainly causing sintering and stable activity. It becomes impossible.
On the other hand, reduction at a temperature exceeding 950 ° C. not only significantly reduces the metal surface area of ruthenium but also causes clogging of the pores of the support or transition to the α phase of the alumina crystal (trigonal lees). The reaction activity is significantly reduced.
[0039]
As the reducing gas, pure hydrogen, hydrogen / water vapor mixed gas, carbon monoxide, or the like can be used. Among these, pure hydrogen gas and hydrogen / water vapor mixed gas are preferably used, and particularly pure hydrogen gas is preferably used.
[0040]
The CO adsorption amount of the catalyst after the reduction treatment is 1.5 ml / g (STP) or more.
When the catalyst is less than 1.5 ml / g (STP), the ruthenium dispersibility on the catalyst is too low, and sufficient activity cannot be obtained.
[0041]
  like thisNaOf the present inventionObtained by manufacturing methodIn order to produce a hydrogen-containing gas by steam reforming a liquid hydrocarbon using a catalyst, the sulfur content is 0.2 ppm or less, the aromatic compound content is 30% by volume or less, and the carbon number is 6 or more. Liquid hydrocarbon is used as a raw material.
[0042]
When the sulfur content exceeds 0.2 ppm, catalyst poisoning due to sulfur tends to occur. In the ruthenium-based catalyst of the present invention, when sulfur poisoning occurs, carbon deposition becomes remarkable, and thus problems in operation due to an increase in differential pressure and clogging of the catalyst also occur.
[0043]
When the aromatic compound content exceeds 30% by volume, the catalyst performance is not impaired, but the hydrogen content at the outlet of the reactor decreases as the aromatic compound content in the raw material increases. This is because the H / C atomic ratio of the raw material hydrocarbon becomes small, and the hydrogen source taken out as generated hydrogen becomes relatively small.
[0044]
When the carbon number is less than 6, the raw material cost is increased.
This means that in the method of the present invention, it is possible to use 6 or more liquid hydrocarbons that are economically inexpensive as raw materials, specifically kerosene or mineral oil equivalent to kerosene. It means that it can be advantageous.
[0045]
Moreover, reaction conditions are S / C ratio 3-10, LHSV5h^-1Hereinafter, the reaction pressure is 2 atm or more.
[0046]
When the S / C ratio is less than 3, carbon deposition becomes remarkable, the differential pressure increases, and further, the catalyst layer is clogged, and there is a possibility that long-time operation cannot be performed.
In addition, there is no particular problem when the S / C ratio is increased, but when it exceeds 10, the water vapor consumption rate increases and the operating cost increases.
[0047]
LHSV is 5h^-1Exceeding the above does not cause deactivation of the catalyst, but there is a possibility that the catalyst and the raw material are not sufficiently in contact. This is considered to occur because an amount of raw material exceeding the reaction frequency is supplied at the active point on the catalyst.
[0048]
There is no particular problem if the reaction pressure is 2 atm or more. Since the amount of raw material that can be supplied to a certain amount of catalyst layer per unit time depends on the pressure, if the pressure is less than 2 atmospheres, the raw material supply amount is restricted. On the other hand, when the pressure is extremely high, equipment using an expensive high-pressure resistant material is required, and therefore, it is usually preferable to set the upper limit to about 50 atm.
[0049]
Under the above reaction conditions, the reaction temperature is preferably 800 to 900 ° C.
As the reaction temperature is lowered, the hydrogen content is reduced due to chemical equilibrium. Therefore, the hydrogen yield is reduced below 800 ° C. On the other hand, when it exceeds 900 ° C., there is a concern about thermal deterioration of the catalyst, and a reactor using an expensive high temperature resistant material is required.
[0050]
The method of the present invention can be carried out using a normal steam reforming reactor, and the number of reactors may be increased as necessary.
[0051]
【Example】
FIG. 1 is a flowchart showing a schematic configuration of a steam reformer used in the following examples and comparative examples.
This apparatus is a laboratory scale micro apparatus for demonstrating the present invention, and a commercial scale apparatus does not necessarily have the same configuration. Further, the minimum necessary devices are shown, and other devices are omitted.
[0052]
In the following examples, the analysis of the product was performed by using a stainless steel (SUS) column (inner diameter: 3 mmφ × 2 m) and a heat fitted with a separation column packed with 60 to 80 mesh Unibeads-C (manufactured by GL Science). A gas chromatograph (GC) with a conductivity type detector (TCD) was used.
The carbon monoxide (CO) adsorption amount was measured by an automatic gas adsorption device (R6015 high temperature specification, manufactured by Okura Riken Co., Ltd.) incorporating TCD-GC.
The amount of supported ruthenium was measured by inductively coupled plasma optical emission spectrometry (ICP).
The amount of sulfur in the liquid hydrocarbon was determined by the electric conduction method.
The amount of carbon deposited on the catalyst is analyzed using a carbon analyzer (Carbon Analyzer, Model EMIA-110, manufactured by HORIBA, Ltd.). Standard carbon steel (Japan Steel Association, Standard Carbon Steel, C: 0) .38 wt%).
The average molecular formula of the raw kerosene is C based on the carbon and hydrogen contents obtained by the CHN analysis method.₆H₁₄It was.
[0053]
Example 1
After 5.8 g of cerium oxide (manufactured by Wako Pure Chemical Industries) powder and 94.1 g of activated alumina powder (manufactured by Merck) were sufficiently mixed in an agate mortar, about 50 ml of pure water was added and further kneaded.
The obtained paste-like mixture was moisture-removed with an infrared hot plate, and then further dried with a constant temperature drier kept at 105 ° C.
This was again pulverized with an agate mortar, then formed into a cylindrical shape (pellet) with a tableting molder, and fired at 900 ° C. for 3 hours in a muffle furnace to prepare a carrier.
[0054]
After immersing 25 g of the above carrier pellets in an aqueous solution in which 1 g of ruthenium trichloride monohydrate (manufactured by Mitsuwa Chemical Co., Ltd., purity 44 to 45%) is dissolved in about 30 ml of pure water, the residual liquid is removed, Using a rotary evaporator, moisture was removed while heating to 40 to 45 ° C. with an infrared hot plate under a vacuum of about 2.7 kPa (20 torr).
This was transferred into 7 to 10 N ammonia water and kept at 30 to 40 ° C., and then slowly stirred with a stirrer for 2 hours. As shown in Chemical Formula 1, ruthenium was insoluble and immobilized.
[0055]
A Buchner funnel was used to separate the catalyst.
Further, even if a dilute aqueous silver nitrate solution was added to the filtrate, it was sufficiently washed with pure water until silver chloride did not become cloudy.
The catalyst was dried in a vacuum dryer at 40 to 45 ° C. for 8 to 10 hours, and composed of 1.4% by weight of ruthenium, 5.5% by weight of cerium oxide, and the remaining alumina, and had a Ce / Ru atomic ratio of 2.24. A was prepared.
[0056]
10 ml of the catalyst obtained above was charged into a SUS cylindrical reaction tube 1 having an inner diameter of 16 mmφ of the steam reformer shown in FIG. 1 to carry out the reaction.
[0057]
Prior to the reaction, the catalyst packed in the reaction tube 1 is subjected to pressure: 8 kg / cm.²G, reduction temperature: 800 ° C., GHSV: 3000 h^-1Thus, the hydrogen was supplied for 8 hours while the flow rate was adjusted by the mass flow controller.
The amount of CO adsorbed on the catalyst after the reduction treatment was 1.8 ml / g (STP).
[0058]
After the hydrogen reduction described above, desulfurized white kerosene obtained by deep desulfurization of JIS No. 1 kerosene (sulfur content: about 0.2 ppm, aromatic compound content: 20% by volume) was added to the catalyst in the reaction tube 1 by a kerosene pump with LHSV: 2 , S / C ratio: 3 was passed, and pure water was supplied by a water pump.
In addition, hydrogen sulfide gas was supplied to the raw material system (mixed system of the above desulfurized white kerosene and pure water) so that the hydrogen sulfide concentration at the inlet of the reaction tube 1 was 8 ppm.
The reaction pressure at this time is 8 kg / cm.²G, the reaction temperature was 800 ° C.
The results are shown in FIG.
[0059]
Example 2
Yttrium oxide (Y₂O₃(Manufactured by Soegawa Chemical) 5.7 g of powder and 94.5 g of the same activated alumina powder as in Example 1, and in the same manner as in Example 1, 1.4 wt% ruthenium, 5.6 wt% yttrium oxide, and the remaining alumina A catalyst B having a Y / Ru atomic ratio of 3.67 and a CO adsorption amount of 1.8 ml / g (STP) was prepared.
The results of the steam reforming reaction using this catalyst B in the same manner as in Example 1 are shown in FIG.
[0060]
Example 3
Using 5.4 g of magnesium oxide (MgO, manufactured by Wako Pure Chemical Industries) powder and 94.7 g of the same activated alumina powder as in Example 1, 1.4 wt% ruthenium and 5. 5 mg of magnesium oxide in the same manner as in Example 1. A catalyst C having an Mg / Ru atomic ratio of 9.21 and a CO adsorption amount of 1.7 ml / g (STP) composed of 3% by weight of the remaining alumina was prepared.
The results of the steam reforming reaction using this catalyst C in the same manner as in Example 1 are shown in FIG.
[0061]
Example 4
Using 5.5 g of barium oxide (BaO, manufactured by Wako Pure Chemical Industries) powder and 94.6 g of the same active alumina powder as in Example 1, 1.4 wt% ruthenium and barium oxide in the same manner as in Example 1. A catalyst D having a Ba / Ru atomic ratio of 2.60 and a CO adsorption amount of 1.6 ml / g (STP) consisting of 4% by weight of the remaining alumina was prepared.
The results of the steam reforming reaction using this catalyst D in the same manner as in Example 1 are shown in FIG.
[0062]
Example 5
Carrier pellets were prepared in the same manner as in Example 1 using 40.8 g and 90.4 g of the same cerium oxide powder and activated alumina powder as in Example 1. Using an aqueous solution obtained by dissolving 100 g of the carrier pellets and 1 g of the same ruthenium trichloride monohydrate as in Example 1 in about 120 ml of pure water, 0.5 wt% ruthenium, cerium oxide 29 in the same manner as in Example 1 A catalyst E having a Ce / Ru atomic ratio of 2.85 wt%, the remaining alumina: 2.85, and a CO adsorption amount of 1.7 ml / g (STP) was obtained.
Table 3 shows the results of the steam reforming reaction performed in the same manner as in Example 1 using this catalyst E.
[0063]
Example 6
Carrier pellets were prepared in the same manner as in Example 1 except that 3.1 g and 97.2 g of the same cerium oxide powder and activated alumina powder as in Example 1 were used, respectively, and the firing temperature was 800 ° C. Using 12.7 g of the carrier pellets and 30 ml of the aqueous ruthenium trichloride monohydrate solution prepared in Example 1, 5% by weight of ruthenium, 3.1% by weight of cerium oxide, and the remaining alumina were formed in the same manner as in Example 1. A catalyst F having a Ce / Ru atomic ratio of 0.36 and a CO adsorption amount of 2.0 ml / g (STP) was obtained.
Table 3 shows the results of the steam reforming reaction performed in the same manner as in Example 1 using this catalyst F.
[0064]
Example 7
The same cerium oxide powder and activated alumina powder as in Example 1 and 10.2 g, 79.6 g, and 10.1 g of yttrium oxide as in Example 2 were used, respectively. A catalyst G having 10.3% by weight of yttrium oxide, 9.5% by weight of cerium oxide, the remaining alumina (Ce + Y) / Ru atomic ratio: 8.22, and a CO adsorption amount of 1.8 ml / g (STP) was obtained.
Table 4 shows the results of the steam reforming reaction performed in the same manner as in Example 1 using this catalyst G.
[0065]
Comparative Example 1
Commercially available steam reforming catalyst H (G-56H-1, manufactured by Gardler, catalog composition, nickel: 17 to 19% by weight, K₂FIG. 2 and Table 5 show the results of the steam reforming reaction performed in the same manner as in Example 1 using O: 0.4 wt%, remaining alumina).
[0066]
Comparative Example 2
The fully dehydrated alumina powder was tableted and molded in a muffle furnace at 900 ° C. for 3 hours to prepare a carrier.
Next, a catalyst was prepared in the same manner as in Example 1 to obtain catalyst I consisting of ruthenium 1.4% by weight and the remaining alumina and having a CO adsorption amount of 1.6 ml / g (STP).
The results of the steam reforming reaction using this catalyst I in the same manner as in Example 1 are shown in FIG.
[0067]
2 shows the kerosene conversion rate (calculated from the following equation) with respect to the reaction time when the catalysts A, B, C, D prepared in Examples 1 to 4 and the catalysts H, I of Comparative Examples 1 and 2 were used. Tables 1 to 5 show the reformed gas composition when the catalysts A to G prepared in Examples 1 to 7 and the catalysts H and I of Comparative Examples 1 and 2 were used. The amount of carbon deposited on the catalyst after the reaction is shown.
[0068]
[Equation 3]
Kerosene conversion rate (%)
= (Number of carbon atoms in product gas) / (number of carbon atoms in kerosene) x 100
The average molecular formula of raw kerosene is C₆H₁₄It was.
[0069]
[Table 1]

[0070]
[Table 2]

[0071]
[Table 3]

[0072]
[Table 4]

[0073]
[Table 5]

[0074]
As is clear from FIG. 2 and Tables 1 to 5, in the hydrogen production by steam reforming using liquid hydrocarbons such as kerosene as raw materials, the supported nickel-based catalyst H (Comparative Example 1) that has been generally used in the past is used. The reaction conditions of the present example, in which the number of carbons of the raw material hydrocarbon is high and the S / C ratio is low compared to the conventional general reaction conditions, are severe for the catalyst. It can be seen that significant degradation occurs.
[0075]
Further, even if the supported ruthenium-based catalyst having excellent carbon precipitation resistance is used, when the catalyst I (Comparative Example 2) not containing the third component is used, the catalyst is covered by the sulfur compound contained in the raw material liquid hydrocarbon. In addition to being gradually poisoned, the conversion rate gradually decreases, and as a secondary inhibition by poisoning, carbon deposition occurs on the catalyst, and the activity deterioration from the middle of the reaction becomes remarkable.
[0076]
  In contrast, the present inventionObtained by manufacturing methodWhen catalysts A to G (Examples 1 to 7) are used, even when liquid hydrocarbons such as kerosene are used as raw materials, not only sufficient catalytic activity close to the equilibrium conversion rate can be obtained, but also due to sulfur compounds in the raw materials. It can be understood that stable catalyst performance can be maintained for a long period of time because problems such as catalyst poisoning and carbon deposition on the catalyst are unlikely to occur.
[0077]
【The invention's effect】
  Steam reforming catalyst of the present inventionManufacturing methodIf a hydrogen production method is employed, a stable steam reforming reaction can be performed over a long period of time under conditions of a low S / C ratio using kerosene or the like as a raw material.₂It is possible to produce hydrogen gas partially containing etc. with good yield and at low cost.
[Brief description of the drawings]
FIG. 1 is a flowchart showing an outline of a steam reformer used in Examples and Comparative Examples of the present invention.
FIG. 2 is a graph showing the results obtained in Examples and Comparative Examples of the present invention.

Claims (3)

Alumina containing 3 to 30% by weight of at least one selected from the group consisting of Group II metal, Group III metal and lanthanoid metal oxides on a catalyst basis is calcined at 800 to 900 ° C. to obtain a carrier, the carrier, after which the aqueous solution of ruthenium chloride ruthenium was supported so that 0.5 to 5% by weight, the ruthenium chloride was insoluble, immobilized ruthenium by converting the hydroxides, followed by 600 to 950 A method for producing a steam reforming catalyst, characterized in that a steam reforming catalyst having a carbon monoxide adsorption amount of 1.5 ml / g or more is obtained by reduction treatment at ° C. At least one selected from the group consisting of Group II metal, Group III metal, and lanthanoid metal oxides is cerium, and ruthenium is reduced to 0.5 so that the atomic ratio of cerium to ruthenium is less than 10. The method for producing a steam reforming catalyst according to claim 1, which is supported by ˜5 wt%. The raw material and water vapor | steam which consist of liquid hydrocarbons with sulfur content of 0.2 ppm or less, aromatic compound content of 30 volume% or less, and 6 or more carbon atoms are obtained by the manufacturing method of Claim 1 or Claim 2. A method for producing hydrogen, wherein the method is brought into contact with a steam reforming catalyst, the steam / carbon ratio represented by the following formula is maintained at 3 to 10, LHSV is kept at 5 h ^-1 or less, and the reaction pressure is kept at 2 atm or more.

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