Catalysts containing copper, zinc oxide, alumina and silica
A catalyst suitable for use in carbon oxide conversion reactions is provided. The catalyst is in the form of a shaped unit formed from an oxidic catalyst powder and contains 30-70% by weight of copper oxide, zinc oxide, alumina and silica. The catalyst has a Si:Al atomic ratio in the range 0.005:1 to 0.15:1, a BET surface area >105 m 2 /g and a copper surface area >37 m 2 /g catalyst. The catalyst is prepared by a co-precipitation method using an alumina sol.
1. A catalyst, suitable for use in carbon oxide conversion reactions, in the form of a shaped unit formed from an oxidic catalyst powder, said catalyst comprising (i) 30-70% by weight of copper oxide (CuO) based on a total weight of the catalyst, (ii) zinc oxide (ZnO), (iii) alumina and (iv) silica, wherein the catalyst has a Si: Al atomic ratio in a range 0.005:1 to 0.15:1, a BET surface area as determined by nitrogen physisorption ≥115 m 2 /g and a copper surface area >37 m 2 /g catalyst.
2. The catalyst according to claim 1 wherein the catalyst is a methanol synthesis catalyst comprising copper oxide in an amount in a range 50 to 70% by weight.
3. The catalyst according to claim 2 wherein a weight ratio CuO:ZnO is in a range of 2:1 to 3.5:1.
4. The catalyst according to claim 2 wherein the catalyst contains 20 to 30% by weight of the zinc oxide, based on a total weight of the catalyst.
5. The catalyst according to claim 1 wherein the catalyst contains 5 to 20% by weight of the alumina, based on a total weight of the catalyst.
6. The catalyst according to claim 1 wherein the catalyst has a copper surface area ≥40 m 2 /g.
7. The catalyst according to claim 1 wherein the catalyst further comprises one or more promoter compounds that are compounds of Mg, Co, Mn, V, Ti, Zr or rare earth metals.
8. The catalyst according to claim 1 wherein the catalyst contains 0.05 to 1.50% by weight of the silica, based on a total weight of the catalyst.
9. The catalyst according to claim 1 wherein the Si: Al atomic ratio is in a range of 0.03:1 to 0.07:1.
10. The catalyst according to claim 1 wherein a Si: Cu atomic ratio is in a range of 0.001:1 to 0.018:1.
11. The catalyst according to claim 1 , wherein the BET surface area of the catalyst, as determined by nitrogen physisorption, is ≥115 m 2 /g up to about 140 m 2 /g.
12. A carbon oxides conversion process which comprises reacting a carbon oxide containing process gas containing at least one of carbon monoxide and carbon dioxide and additionally containing hydrogen and/or steam, in the presence of a catalyst according to claim 1 .
13. The carbon oxides conversion process according to claim 12 wherein the process is selected from methanol synthesis and the water-gas shift reaction.