Conversion of carbon dioxide to methanol using bi-reforming of methane or natural gas
The invention provides for a method of forming methanol by combining a mixture of methane, water and carbon dioxide under specific reaction conditions sufficient to form a mixture of hydrogen and carbon monoxide which are then reacted under conditions sufficient to form methanol. The molar ratio of hydrogen to carbon monoxide is at least two moles of hydrogen to one mole of carbon monoxide and the overall molar ratio between methane, water and carbon dioxide is about 3:2:1. Methane, carbon dioxide and water are bi-reformed over a catalyst. The catalyst includes a single metal, a metal oxide, a mixed catalyst of a metal and a metal oxide or a mixed catalyst of at least two metal oxides.
1. A method of preparing methanol from carbon dioxide, water and a methane source which comprises:
conducting a bi-reforming reaction, wherein the only reactants are methane, carbon dioxide and water in a mole ratio of about 3:1:2 as follows: 3CH 4 +2H 2 O+CO 2 by:
conducting wet reforming of methane from the methane source with water to form carbon monoxide and hydrogen as follows:
2CH 4 +2H 2 O→2CO+6H 2 ;
conducting dry reforming of methane from the methane source with carbon dioxide to form carbon monoxide and hydrogen as follows:
CH 4 +CO 2 →2CO+2H 2 ;
combining effluents consisting of the carbon monoxide and hydrogen from the wet and dry reforming reactions without separation of components of the reforming reactions or their effluents to produce a mixture of hydrogen and carbon monoxide having a molar ratio of hydrogen to carbon monoxide that is 2:1 to 2.1:1; and
converting the molar mixture of hydrogen and carbon monoxide under conditions sufficient to exclusively form methanol, as follows:
4CO+8H 2 →4CH 3 OH.
2. The method of claim 1 , wherein the methane, carbon dioxide and water are reacted in the single step.
3. The method of claim 2 , wherein the molar mixture of hydrogen and carbon monoxide is present at a mole ratio of 2.05 to 1.
4. The method of claim 2 , wherein the combined bi-reforming step is conducted at a temperature of about 800 to 1100° C.
5. The method of claim 2 , wherein the bi-reforming is conducted without any significant coke formation.
6. The method of claim 2 , wherein the bi-reforming is conducted in the presence of a combination of metal and metal oxide catalysts.
7. The method of claim 6 , wherein the catalyst combination is Ni and V 2 O 5 ; Ni 2 O 3 and V 2 O 5 ; or Ni 2 V 2 O 7 and Ni 3 V 2 O 8 .
8. The method of claim 7 , wherein the catalyst combination is supported on a high surface or nanostructured support.
9. The method of claim 8 , wherein the support comprises silica, alumina, a metal oxide or a metal.
10. The method of claim 1 , wherein the methane source includes any conventional natural gas.
11. A method of preparing methanol from carbon dioxide, water and a methane source which comprises:
conducting a bi-reforming reaction by providing methane, water and carbon dioxide in a mole ratio of 3:1:2 as the only reactants as follows:
3CH 4 +2H 2 O+CO 2 ;
reacting the methane, water and carbon dioxide from the bireforming reaction without separation of the reactants or their effluents to produce an exclusive mixture of hydrogen and carbon monoxide in a mole ratio of 2:1 to 2.1:1; and
reacting the mixture of hydrogen and carbon monoxide under conditions sufficient to exclusively form methanol.
12. The method of claim 11 , wherein the reaction of methane, water and carbon dioxide is conducted in a single step.
13. The method of claim 11 , wherein the reaction of methane, water and carbon dioxide is conducted by:
wet reforming of methane from the reaction of a methane source with water to form carbon monoxide and hydrogen as follows:
2CH 4 +2H 2 O→2CO+6H 2 ;
dry reforming of methane from a methane source with carbon dioxide to form carbon monoxide and hydrogen as follows:
CH 4 +CO 2 →2CO+2H 2 ;
and
combining effluents of the wet reforming and dry reforming reactions to obtain the mixture of hydrogen and carbon monoxide.
14. The method of claim 12 , wherein the molar mixture of hydrogen and carbon monoxide is present at a mole ratio of 2.05 to 1.
15. The method of claim 12 , wherein the single bi-reforming step is conducted at a temperature of about 800 to 1100° C.
16. The method of claim 11 , wherein the reacting of methane, water and carbon dioxide is conducted without any significant coke formation.
17. The method of claim 11 , wherein the reacting of methane, water and carbon dioxide is conducted in the presence of a combination of metal and metal oxide catalysts.
18. The method of claim 17 , wherein the catalyst combination is Ni and V 2 O 5 ; Ni 2 O 3 and V 2 O 5 ; or Ni 2 V 2 O 7 and Ni 3 V 2 O 8 .
19. The method of claim 18 , wherein the catalyst combination is supported on a high surface or nanostructured support.
20. The method of claim 19 , wherein the support comprises silica, alumina, a metal oxide or a metal.