JP4780273B2 - Method for producing catalyst for lightening heavy oil - Google Patents

Description

The present invention relates to a method for producing a catalyst for lightening heavy oil used in a steam cracking method.

  Conventionally, hydrogenation type or carbon removal type methods are known as methods for lightening heavy oil, which is an inferior fuel, to light oil, which is a high quality fuel, by increasing the H / C ratio. The hydrogenation type method is a method of reforming using a hydrogenation catalyst such as a Co-Mo system under high temperature and high pressure conditions, but there are problems in that the hydrogen production cost is high and the regeneration ratio of the catalyst is low. there were. On the other hand, the carbon removal type method is a method in which heavy oil is thermally decomposed and reformed, and heavy metals in the oil are concentrated and removed in the residue. There is a problem that the next treatment is required and it is difficult to effectively use by-products such as residues.

Therefore, as a next-generation lightening method, a steam cracking method that lightens heavy oil in a steam atmosphere has attracted attention. The applicant developed a steam cracking method using an iron compound as a catalyst, and previously proposed it. (See Patent Document 1). In addition, a steam cracking method using a Ni-based catalyst has also been proposed. However, Ni-based catalysts are expensive and difficult to recover. On the other hand, although iron-based catalysts are cheap and easy to recover, they are slightly inferior in the ability to lighten heavy oils, and do not show stable activity in a high-temperature steam atmosphere, and are susceptible to deterioration due to coke adhesion. However, there has been a demand for the development of an iron-based catalyst used in the steam cracking method which does not have these drawbacks and is low in production cost.
JP 2001-129405 A

The present invention solves the above problems and satisfies all performances such as high lightening ability, stable activity in a steam atmosphere, deterioration resistance, and deactivation resistance, which are required as a catalyst for steam cracking. The present invention has been completed for the purpose of providing a method for producing a catalyst for lightening heavy oil that can be produced at low cost.

In order to solve the above-mentioned problems, the invention of claim 1 is characterized in that an alkaline coprecipitate of Fe and Al is impregnated in a Zr-containing aqueous solution, and then the solid content obtained by filtration and washing is heat-treated in a steam atmosphere. Thus, an iron oxide catalyst containing Al having a ratio of Al / (Al + Fe) of 8 to 24 mol% and Zr is obtained. In the invention of claim 2, after making Fe salt, Al salt and Zr salt into an aqueous solution, an alkali solution is added to cause alkali coprecipitation, and then the solid content separated by solid-liquid separation is washed by filtration to obtain a cake-like filtrate. This is heat-treated to obtain an iron oxide catalyst containing Al having a ratio of Al / (Al + Fe) of 8 to 24 mol% and Zr .

As a method for producing a catalyst for lightening a heavy oil of the present invention, a solution obtained by impregnating an alkali-precipitated Fe salt and an Al salt with a Zr-containing aqueous solution and then filtering and washing the solid content is treated with steam. Since a Zr / Fe—AlO _x catalyst is obtained by heat treatment in an atmosphere, the catalyst can be produced easily and inexpensively.
In addition, as a catalyst production method, after making Fe salt, Al salt and Zr salt into an aqueous solution, an alkali solution is added to cause alkali coprecipitation, and then solid-liquid separated solid content is filtered and washed to obtain a cake-like filtrate. This can be heat-treated to obtain a Zr / Fe—AlO _x catalyst. In this case as well, the catalyst can be produced simply and inexpensively.

Below, the preferable form of this invention is shown.
The catalyst of the present invention is used in, for example, a plastic oil conversion process in which waste plastic is thermally decomposed to obtain a light oil having a high octane number. In particular, the catalyst of the present invention is used in a steam decomposition method for lightening heavy oil in a steam atmosphere. It is used. In the catalyst of the present invention, Zr is supported on an iron-based catalyst made of an alkali coprecipitate of Fe salt and Al salt.
It said Fe salt, the Al salt, _{e.g., Fe (NO 3) 3 ·} 9H 2 O and Al _{(NO 3)} can be used nitrates of 3 · 9H ₂ O and the like. Then, by supporting the Zr on the iron-based catalyst comprising a co-precipitate obtained by alkali co-precipitation, the catalyst Zr / Fe-AlO _x is formed.

As described above, the catalyst of the present invention is basically an iron-based catalyst, and exhibits high lightening ability in the steam cracking method and can be produced at low cost. Further, since the supported Zr acts as a co-catalyst that promotes the separation of water molecules, it exhibits stable activity in a water vapor atmosphere and exhibits excellent deterioration resistance and deactivation resistance.
The catalyst of the present invention is considered to function as a catalyst for the reaction shown in [Chemical Formula 1]. Thereby, heavy oil will be decomposed | disassembled effectively.

［化１］において、Ｒ_１、Ｒ_２は有機基を示す。また、水の分解により活性酸素を生じさせ、［化２］に示すように、該活性酸素による酸化の触媒としても機能する。

In [Chemical Formula 1], R ₁ and R _{2 each} represents an organic group. Moreover, active oxygen is generated by the decomposition of water, and as shown in [Chemical Formula 2], it also functions as a catalyst for oxidation by the active oxygen.

  The catalyst of the present invention has an iron-based porous structure and functions as a redox catalyst while maintaining the reaction equilibrium as shown in [Chemical Formula 3] and [Chemical Formula 4].

In the catalyst of the present invention, the point that the supported Zr acts as a promoter for promoting the separation of water molecules will be described. Illustrates a process of generating CO from 1 CO _2, FIG. 2 is a diagram showing a production process of H ₂ from the H _{2 O,} that Zr is activated to promote dissociation of water molecules I understand.

In the catalyst Zr / Fe—AlO _x described above, the ratio of the Al content to the Fe content in the catalyst is preferably in the range of 8 to 24 mol% in terms of Al / (Al + Fe). The reason is that when the amount is less than 8 mol%, the structural stability of the Fe catalyst decreases, and when it exceeds 24 mol%, the amount of Fe active species decreases and the activity decreases.

Further, the supported amount of Zr is preferably in the range of 1.7～7.7Wt% in terms of ZrO _2. The reason is that if it is less than 1.7 wt%, the amount of ZrO ₂ for water splitting is small and sufficient active oxygen and hydrogen are not generated, and if it is more than 7.7 wt%, the supported ZrO ₂ is the main catalyst (heavy catalyst). This is because most of the surface of FeO _x , which is the place where the decomposition reaction of the refined oil molecules proceeds, covers most of the surface of the FeO _x , so that the number of heavy oil decomposition sites decreases and the activity decreases.

Next, the manufacturing method of the catalyst of this invention is demonstrated. As a production method, a coprecipitation / impregnation method and a coprecipitation method can be applied, and each method will be described below.
[Coprecipitation / impregnation method]
And Fe salts _{(Fe (NO 3) 3 ·} 9H 2 O), the Al salt _{(Al (NO 3) 3 ·} 9H 2 O) and an aqueous solution dissolving stirred in water, an alkaline solution such as this in NaOH and aqueous ammonia Is added to coprecipitate Fe and Al. After impregnating the alkaline coprecipitate in a Zr-containing aqueous solution, the solid content obtained by filtration and washing is heat-treated in a steam atmosphere. Thus, a Zr / Fe—AlO _x catalyst can be obtained.

[Co-precipitation method]
An Fe salt, an Al salt, and a Zr salt (ZrOCl ₂ .8H ₂ O) are stirred and dissolved in water to obtain an aqueous solution. An alkaline solution is added to this aqueous solution to cause coprecipitation, and then the solid content separated by solid-liquid separation is washed by filtration to obtain a cake-like filtrate. Finally, the filtrate is heat treated. Thus, a Zr / Fe—AlO _x catalyst can be obtained.

The catalyst obtained as described above can be regenerated to the initial state by performing air calcination after the reaction. That is, the iron oxide that has become magnetite (Fe ₃ O ₄ ) after the catalytic reaction is returned to hematite (α-Fe ₂ O ₃ ). In this case, it was confirmed that the Zr / Fe—AlO _x catalyst obtained by the coprecipitation / impregnation method increases the specific surface area and improves the catalytic activity. Further, it has been confirmed that the Zr / Fe—AlO _x catalyst obtained by the coprecipitation method has little deterioration due to the reaction, and most remains as hematite (α-Fe ₂ O ₃ ) after the reaction.

_{Fe (NO 3) 3 · 9H} 2 O: 226.2g, Al (NO 3) 3 · 9H 2 O: 52.5g, ZrOCl 2 · 8H 2 O: stirring dissolved in tap water 1.5 liters of 11.3g To do. Subsequently, it stirred for 1 hour, adding NaOH solution (48.7%) gradually. Thereafter, solid-liquid separation was performed, and the obtained solid content was filtered and washed with hot water. Next, the obtained cake-like filtrate was heat-treated at 500 ° C. for 1 hour to obtain 56 g of Zr / Fe—AlO _x catalyst (ZrO ₂ : 7.9 wt%, Al / (Al + Fe): 20 mol%). It was.

  FIG. 3 shows the result of lightening atmospheric residue using a Zr / Fe—AlOx catalyst by steam cracking. In the first reaction, gasoline and kerosene can be obtained in high yields of 40% or more, and light oil can be obtained in high yields of 70% or more. Residues can be eliminated and the catalyst has excellent characteristics. It was. When a catalyst is not used as a comparative example, the same lightening results are shown using an FeOx catalyst (described as Fe catalyst in the figure) and a Zr / FeOx catalyst (described as Zr / Fe catalyst in the figure). Non-catalyst and FeOx have a lower yield of light oil than the catalyst of the present invention. The activity of Zr / FeOx is almost the same as that of the catalyst of the present invention at the first time, but when the second and third times after regeneration, the yield is 37% for gasoline and kerosene combined. Decreases significantly to 65% or less. However, the Zr / Fe—AlOx catalyst of the present invention is stable, and lightening is promoted by repeating regeneration. In the third yield, gasoline and kerosene are 46%, and if diesel oil is included, it is 77%. It was clear that the performance was excellent.

FIG. 4 shows the pore size distribution of the Zr / Fe—AlO _x catalyst. The catalyst of the present invention shows almost no difference in pore distribution before the reaction (use) and after regeneration, resulting in clogging. It was confirmed that it was difficult.

FIG. 5 is a graph showing the relationship between the decomposition rate constant of the Zr / Fe—AlO _x catalyst of the present invention and the number of regenerations. Each time the regeneration operation is performed, the decomposition rate constant increases and the processing efficiency increases. It could be confirmed. This seems to be because fine pores develop by performing air firing.

As is clear from the above explanation, the present invention is such that Zr is supported on an iron-based catalyst composed of an alkaline coprecipitate of Fe salt and Al salt, and the supported Zr promotes separation of water molecules. Therefore, it exhibits a stable activity in a water vapor atmosphere, and also exhibits excellent resistance to deterioration and deactivation.
Further, a Zr / Fe—AlO _x catalyst is obtained by impregnating a Zr-containing aqueous solution with a co-precipitated Fe salt and Al salt, and then heat-treating the solid content obtained by filtration and washing in a steam atmosphere. Method, after making Fe salt, Al salt and Zr salt into aqueous solution, adding alkali solution to coprecipitate with alkali, then solid-liquid separated solid content is filtered and washed to make cake-like filtrate, and this is heat treated According to the manufacturing method for obtaining a Zr / Fe-AlO _x catalyst Te, easily and inexpensively and thus capable of producing a Zr / Fe-AlO _x catalyst.

It is a diagram illustrating a process of generating CO from CO _2. It is a diagram showing a production process of _{H 2} from the H ₂ O. It is a graph which shows a yield when carrying out steam decomposition of a normal-pressure residual oil. It is a graph which shows the pore diameter distribution of the catalyst of this invention. It is a graph which shows the relationship between the decomposition rate constant of the catalyst of this invention, and the frequency | count of regeneration .

Claims (2)

A solid content obtained by impregnating an alkaline coprecipitate of Fe and Al in a Zr-containing aqueous solution and then filtering and washing is heat-treated in a water vapor atmosphere, and the ratio of Al / (Al + Fe) is 8 to 24 mol%. A method for producing a catalyst for lightening heavy oil, characterized in that an iron oxide catalyst containing Al and Zr is obtained. After making Fe salt, Al salt, and Zr salt into an aqueous solution, an alkali solution is added to cause alkali coprecipitation, and then the solid content separated by solid-liquid separation is filtered and washed to obtain a cake-like filtrate, which is heat-treated, and Al A method for producing a catalyst for lightening heavy oil, characterized in that an iron oxide-based catalyst containing Al having a ratio of / (Al + Fe) of 8 to 24 mol% and Zr is obtained.

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