Methods for preparing high temperature water gas shifting catalyst, catalyst and process for reducing carbon monoxide

Patent metadata

Field	Value
Publication number	US-11679381-B2
Application number	US-202117496459-A
Country	US
Kind code	B2
Filing date	Oct 7, 2021
Priority date	Oct 8, 2020
Publication date	Jun 20, 2023
Grant date	Jun 20, 2023

Abstract

The present invention deals with catalysts for the conversion of CO by the shifting reaction of high temperature water gas, free from chromium and iron, consisting of alumina promoted by potassium, by zinc and copper oxides and in a second embodiment also additionally nickel. The catalysts thus prepared maintain high CO conversion activity, not having the environmental limitations or operating limitations with low excess steam in the process, which exist for catalysts in accordance with the state of the art. Such catalysts are used in the hydrogen or synthesis gas production process by the steam reforming of hydrocarbons, allow the use of low steam/carbon ratios in the process, exhibiting high activity and stability to thermal deactivation and lower environmental restrictions for production, storage, use and disposal, than the industrially used catalysts based on iron, chromium, and copper oxides.

First claim

The invention claimed is:

1. Method for preparing a water gas shift reaction catalyst, free of iron or chromium, comprising:
a) Impregnating an alumina support with an aqueous solution of a potassium salt;
b) Drying the support to remove the solvent and calcine the alumina support at temperatures between 400° C. and 800° C. to obtain a potassium promoted alumina, preferably forming potassium aluminate species;
c) Impregnating the potassium promoted alumina with an aqueous polar solution containing a soluble zinc salt and a soluble copper salt;
d) Drying at a temperature between 80° C. and 120° C., and calcining the material at temperatures between 300° C. and 500° C., to obtain a catalyst consisting of alumina promoted with potassium and containing zinc and copper oxides;
e) Impregnating the material obtained in step (d) with an aqueous solution of a nickel salt, drying at a temperature between 80° C. and 120° C., optionally calcining between 350° C. to 450° C., to obtain a catalyst consisting of alumina promoted with potassium and containing zinc and copper oxides promoted by nickel.

2. Method, according to claim 1 , wherein the alumina is selected from boehmite, gamma, theta-alumina or alumina promoted with lanthanum.

3. Method, according to claim 1 , wherein the potassium salt is selected from hydroxide, nitrate or carbonate, the zinc salt is nitrate or carbonate and the copper and nickel salts are nitrates or acetates.

4. Method, according to claim 1 , wherein the alumina support is simultaneously impregnated with potassium salt, zinc salt, copper salt and nickel salt in a polar aqueous solution, followed by drying at temperatures between 80° C. to 120° C., and calcination at temperatures between 300° C. to 500° C.

5. Catalysts, as obtained by the method defined in claim 4 , wherein having a specific area greater than 60 m 2 /g, a potassium content between 4 to 15% m/m, zinc oxide content between 5 to 30% m/m, copper oxide content between 1 to 4% w/w, a Zn/Al molar ratio less than 0.4 and an atomic Cu/Ni ratio between 6 to 12, based on the weight of the catalyst.

6. Catalysts, as obtained by the method defined in claim 1 , wherein having a specific area greater than 60 m 2 /g, a potassium content between 4 to 15% m/m, zinc oxide content between 5 to 30% m/m, copper oxide content between 1 to 4% w/w, a Zn/Al molar ratio less than 0.4 and an atomic Cu/Ni ratio between 6 to 12, based on the weight of the catalyst.

7. Process for reducing carbon monoxide, by the water-gas shift reaction, comprising contacting the catalyst of claim 6 , with a synthesis gas containing between 5 to 30% v/v of CO, a vapor/dry gas ratio between 0.05 to 0.6 mol/mol, a reactor inlet temperature between 280° C. to 400° C., a reactor outlet temperature between 380° C. to 500° C. and an operating pressure in the range of 10 to 40 kgf/cm 2 .

8. Process, according to claim 7 , wherein the synthesis gas contains between 8 to 20% v/v of CO, a vapor/dry gas ratio between 0.1 to 0.3 mol/mol, an inlet temperature in the reactor between 300° C. to 350° C. and a reactor outlet temperature between 400° C. to 450° C. and an operating pressure in the reactor in the range of 20 to 30 kgf/cm 2 .

9. Process, according to claim 7 , wherein the water-gas shift reaction takes place in a fixed bed reactor containing two regions, wherein a first region comprises up to 40% v/v of the catalyst consisting of alumina containing potassium, and zinc and copper oxides promoted by nickel and a second region comprises a catalyst consisting of alumina containing potassium, and zinc and copper oxides.

10. Method for preparing high temperature gas shifting catalyst, wherein comprising the following steps:
f) Impregnating an alumina support with an aqueous solution of a potassium salt;
g) Drying the support to remove the solvent and calcine the support at temperatures between 400° C. and 800° C. to obtain a potassium promoted alumina, preferably forming potassium aluminate species;
h) Impregnating the potassium promoted alumina with an aqueous polar solution containing a soluble zinc salt and a soluble copper salt;
i) Drying at a temperature between 80° C. and 120° C., and calcining the material at temperatures between 300° C. and 500° C., to obtain a catalyst consisting of alumina promoted with potassium and containing zinc and copper oxides.

11. Catalysts, according to claim 10 , wherein having a specific area greater than 60 m 2 /g, a potassium content between 3 to 10% m/m, zinc oxide content between 5 to 30% m/m, copper oxide content between 1 to 4% m/m, a Zn/Al molar ratio less than 0.4 based on the weight of the catalyst.

12. Process for reducing carbon monoxide, by the water-gas shift reaction, comprising contacting the catalyst of claim 11 with a synthesis gas containing between 5 to 30% v/v of CO, a vapor/dry gas ratio between 0.05 to 0.6 mol/mol, a reactor inlet temperature between 280° C. to 400° C., a reactor outlet temperature between 380° C. to 500° C. and an operating pressure in the range of 10 to 40 kgf/cm 2 .

Assignees

• Petroleo Brasileiro S A —Petrobras

Inventors

• Bittencourt Roberto Carlos Pontes

Classifications

• C01B3/16

  using catalysts · CPC title

• B01J6/001

  Calcining · CPC title

• B01J37/0236

  Drying, e.g. preparing a suspension, adding a soluble salt and drying · CPC title

• C01B2203/1628

  Controlling the pressure · CPC title

• C01B2203/1082

  Composition of support materials · CPC title