Hydrogenation of carbon monoxide using sulfide catalysts

Details Hydrogenation of carbon monoxide using sulfide catalysts Hydrogenation of carbon monoxide using sulfide catalysts

2001-11-13

2003-03-18

Parsa, J. (Department: 1621)

Chemistry: fischer-tropsch processes; or purification or recover

Group viii metal containing catalyst utilized for the...

C518S700000, C518S717000

Reexamination Certificate

active

06534553

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-217017, filed Jul. 17, 2001, the entire contents of which are incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a process for hydrogenating carbon monoxide. More specifically, this invention relates to a process for producing synthetic fuels of low environmental impact from synthesis gas. In one aspect, this invention concerns a catalyst for use in the hydrogenation of carbon monoxide.
2. Description of the Related Art
Various useful organic chemicals have been produced from carbon resources like petroleum, coal, natural gas, and biomass in the following manner. Firstly, a synthesis gas, a mixture of carbon monoxide and hydrogen, is produced through a reforming reaction or a coal gasification. The synthesis gas is then allowed to react on specific catalysts at high temperature and at high pressure, thus converted to hydrocarbons or oxygenates.
These organic chemicals thus obtained will suppress the emission of toxic substances when used as fuel, since they contain little sulfur and nitrogen compounds owing to their distinctive manufacturing processes. In particular, methanol, which is mostly produced from synthesis gases and used as an alternative fuel or a gasoline additive, has recently received much attention as a hydrogen source for the fuel cell. In the stream of rising environmental-conscious, an improved manufacturing method with higher productivity is desired.
In the reaction of synthesis gases, catalysts including metals such as Cu, Fe, and Co are generally used. Typical review articles are in the text “Studies in surface science and catalysis, vol. 81, NATURAL GAS CONVERSION”, H. E. Curry-Hyde, R. F. Howe, Elsevier (1994).
While Cu is widely used for the production of methanol, it is also known in the art that Rh, Pd, Ir and Pt have considerable activity for the alcohol synthesis and that the activity may be promoted by the addition of alkali metal, alkali earth metal, and rare earth elements.
For instance, U.S. Pat. No. 4,119,656 discloses that methanol is selectively produced on a silica supported Pd (Pd/SiO
2
) catalyst. U.S. Pat. Nos. 4,289,709 and 4,289,710 disclose the promoting effect of Li, Mg, Sr, Ba, Mo, and Ca in the methanol synthesis on a Pd/SiO
2
catalyst. A. Gotti and R. Prins in Journal of Catalysis, 175, 302-311(1998) have mentioned the promoting effect of Ca and La on activity and selectivity in the methanol synthesis.
Among these catalysts, Cu catalysts are commercially used for the methanol synthesis because of their low cost and availability, in spite of the drawbacks of requiring high temperature and high pressure conditions. However, Cu catalysts are easily poisoned by various chemical substances in feed gases, particularly by a trace amount of sulfur compounds such as hydrogen sulfide. To avoid this sulfur poisoning, sulfur compounds must be reduced far less than 1 ppb through a desulfurization facility before the reforming or hydrogenation reaction process. Consequently, the use of Cu catalysts make the manufacturing process complicated and expensive.
Nevertheless, misoperation or accidents leading to contamination of sulfur compounds might damage the catalysts.
On this sulfur poisoning, Jpn. Pat. Appln. KOKAI Publication Nos. 55-139324 and 55-139325 disclose a production process of hydrocarbons with sulfur tolerant catalysts that consist essentially of the metal, oxide or sulfide of Mo, W, Re, Ru, Ni, Pd, Rh, Os, Ir or P, and alkali metal or alkaline earth metal. In these applications, it is noted that a catalyst consisting of MoO
3
, K
2
O and carborundum shows no remarkable change in activity and gaseous alkene selectivity even when a synthesis gas contains 20 ppm of hydrogen sulfide.
U.S. Pat. No. 4,749,724 discloses that C1-C4 alcohols are produced from a synthesis gas containing hydrogen sulfide at high pressures around 10 MPa on a sulfided Mo, W or Re catalyst added with alkali metal or alkaline earth metal.
As mentioned above, Cu catalysts are deactivated by sulfur compounds, so that the content of sulfur compounds must be lowered far less than 1 ppb by means of upstream desulfurization units. On the other hand, aforementioned sulfide catalysts containing Mo, W or Re require high pressure conditions to achieve proper activity and selectivity.
BRIEF SUMMARY OF THE INVENTION
The object of the present invention is to provide a method for hydrogenating carbon monoxide with high productivity under mild conditions and with a simple manufacturing process. It is another object of the present invention to provide sulfide catalysts with high durability, especially excellent sulfur tolerance in the production of synthetic fuels.
According to one aspect of the present invention, there is provided a method for producing synthetic fuels by hydrogenating carbon monoxide comprising contacting a feed gas containing carbon monoxide and hydrogen with a supported metal sulfide catalyst comprising Pd and at least one promoter selected from the group consisting of alkali metal, alkaline earth metal, and rare earth elements.
According to another aspect of the present invention, there is provided a method for producing synthetic fuels by hydrogenating carbon monoxide comprising contacting a feed gas containing carbon monoxide and hydrogen with a catalyst including a solid acid and a supported metal sulfide comprising Pd and at least one promoter selected from the group consisting of alkali metal, alkaline earth metal, and rare earth elements.
DETAILED DESCRIPTION OF THE INVENTION
The catalyst used in the practice of the invention is a supported metal sulfide comprising Pd and at least one promoter selected from the group consisting of alkali metal, alkaline earth metal, and rare earth elements. The metal sulfide catalyst may be prepared by sulfiding of corresponding Pd compounds.
The sulfiding may be carried out by contacting the Pd compounds with sulfur compounds such as lithium sulfide, sodium sulfide, potassium sulfide, ammonium sulfide, hydrogen sulfide, and thiophene with gradually increasing the temperature up to 150-250° C. and then to a predetermined operation temperature where temperature is maintained for 1-4 hours. The sulfiding may also be carried out by treating the Pd compounds with sulfur compounds contained in high concentrations in a feed gas during the hydrogenation reaction.
The exemplary Pd compounds include metallic palladium such as palladium black, palladium carbon, and palladium on calcium carbonate, palladium complexes or salts such as ammonium tetrachloropalladate (NH
4
)
2
PdCl
4
, tetraamminepalladium nitrate Pd(NH
3
)
4
(NO
3
)
2
, tetraamminepalladium chloride Pd(NH
3
)
4
Cl
2
, tetraamminepalladium bromide Pd(NH
3
)
4
Br
2
, diamminedichloropalladium PdCl
2
(NH
3
)
2
, diamminedinitropalladium Pd(NH
3
)
2
(NO
2
)
2
, palladium acetate Pd(CH
3
COO)
2
, palladium oxide PdO, palladium cyanide Pd(CN)
2
, palladium chloride PdCl
2
, palladium bromide PdBr
2
, palladium iodide PdI
2
, palladium nitrate Pd(NO
3
)
2
, palladium hydroxide Pd(OH)
2
, palladium sulfate PdSO
4
, palladium sulfides PdS, PdS
2
, bis(acetylacetonato)palladium Pd(C
5
H
7
O
2
)
2
, bis(ethylenediamine)palladium chloride Pd(C
2
H
8
N
2
)
2
Cl
2
, tetrakis(triphenylphosphine)palladium Pd(PPh
3
)
4
, potassium tetracyanopalladium K
2
Pd(CN)
4
, lithium tetrachloropalladate Li
2
PdCl
4
, and calcium tetrachloropalladate CaPdCl
4
.
The exemplary promoter selected from the group consisting of alkali metal, alkaline earth metal, and rare earth elements include Na, K, Ca, Mg, La, Th, etc. These materials may be used alone or in combination thereof. The promoter may be contained originally in the Pd compounds or supports, or added afterwards. A preferred amount of the promoter is represented by the promoter/Pd molar ratio of 0.01 to 10. The promoter less than 0.01 mol/mol-Pd has little effects on the catalytic activity, while the promoter more than 10 mol/m

Affiliated with

Also associated with

Rating

Hydrogenation of carbon monoxide using sulfide catalysts does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Hydrogenation of carbon monoxide using sulfide catalysts, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hydrogenation of carbon monoxide using sulfide catalysts will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3085041