Promoted nickel-magnesium oxide catalysts and process for producing synthesis gas

• US 20030165424A1
• Filed: 01/09/2003
• Published: 09/04/2003
• Est. Priority Date: 02/22/2002
• Status: Active Grant

• Current Assignee: Phillips 66 Company
• Original Assignee: Conoco Incorporated (ConocoPhillips)
• Inventors: Wright, Harold A., Ramani, Sriram, Minahan, David M., Allison, Joe D.
• Granted Patent: US 7,223,354 B2
• Time in Patent Office: Days
• US Class Current: 423/651
• CPC Class Codes: B01J 23/76 combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
• CPC Class Codes: B01J 23/78 with alkali- or alkaline earth metals
• CPC Class Codes: B01J 23/83 with rare earths or actinides
• CPC Class Codes: B01J 23/835 with germanium, tin or lead
• CPC Class Codes: B01J 23/85 Chromium, molybdenum or tungsten
• CPC Class Codes: B01J 23/889 Manganese, technetium or rhenium
• CPC Class Codes: B01J 23/8892 Manganese
• CPC Class Codes: B01J 23/894 with rare earths or actinides
• CPC Class Codes: B01J 23/8946 with alkali or alkaline earth metals
• CPC Class Codes: B01J 23/8986 with manganese, technetium or rhenium
• CPC Class Codes: B01J 23/8993 with chromium, molybdenum or tungsten
• CPC Class Codes: B01J 37/0205 in several steps
• CPC Class Codes: B01J 37/08 Heat treatment B01J37/0009, B01J37/0018 take precedence
• CPC Class Codes: C01B 2203/0261 containing a catalytic partial oxidation step [CPO]
• CPC Class Codes: C01B 2203/1011 Packed bed of catalytic structures, e.g. particles, packing elements
• CPC Class Codes: C01B 2203/1029 Catalysts in the form of a foam
• CPC Class Codes: C01B 2203/1052 Nickel or cobalt catalysts
• CPC Class Codes: C01B 2203/1058 Nickel catalysts
• CPC Class Codes: C01B 2203/1082 Composition of support materials
• CPC Class Codes: C01B 2203/1241 Natural gas or methane
• CPC Class Codes: C01B 3/386 : Catalytic partial combustion
• CPC Class Codes: C01B 3/40 : characterised by the catalyst
• CPC Class Codes: Y02P 20/52 : using catalysts, e.g. selective catalysts

Abstract

A process and catalyst are disclosed for the catalytic partial oxidation of light hydrocarbons to produce synthesis gas at superatmospheric pressures. A preferred catalyst used in the process includes a nickel-magnesium oxide solid solution and at least one promoter chosen from Cr, Mn, Mo, W, Sn, Re, Rh, Ru, Ir, Pt, La, Ce, Sm, Yb, Lu, Bi, Sb, In and P, and oxides thereof, carried on a refractory support.

Claims

1. A method of converting a light hydrocarbon and O₂ to a product mixture containing CO and H₂, the process comprising:

forming a reactant gas mixture comprising a light hydrocarbon and O₂; and

passing said reactant gas mixture over a catalyst comprising

at least one promoter chosen from the group consisting of Cr, Mn, Mo, W, Sn, Re, Rh, Pd, Ru, Ir, Pt, La, Ce, Sm, Yb, Lu, Bi, Sb, In and P, and oxides thereof;

a solid solution comprising nickel and/or nickel oxide and magnesium oxide; and

a refractory support,

said catalyst having enhanced stability and enhanced resistance to coking under catalytic partial oxidation promoting conditions,

such that a product mixture containing CO and H₂ is produced.

2. The method of claim 1 comprising passing said reactant gas mixture over said catalyst at a pressure in excess of 100 kPa.

3. The method of claim 2 wherein said pressure is up to about 32,000 kPa.

4. The method of claim 2 wherein said pressure is in the range of 200-10,000 kPa.

5. The method of claim 1 comprising passing said reactant gas mixture over said catalyst at a gas hourly space velocity of at least 20,000 hr⁻

1.

6. The method of claim 1 comprising passing said reactant gas mixture over said catalyst at a gas hourly space velocity up to 100,000,000 hr⁻

1.

7. The method of claim 1 wherein the residence time is no more than 200 milliseconds for each portion of said reactant gas mixture contacting said catalyst.

8. The method of claim 7 wherein the catalyst residence time is 20 milliseconds or less.

9. The method of claim 8 wherein the catalyst residence time is 10 milliseconds or less.

10. The method of claim 1 comprising preheating said reactant gas mixture to a temperature in the range of 30°

C.-750°

C. before contacting said catalyst.

11. The method of claim 1 wherein said reactant gas mixture comprises a carbon:

oxygen molar ratio in the range of 1.5;

1 to 3.3;

1.

12. The method of claim 11 wherein said carbon:

oxygen molar ratio is about 2;

1.

13. The method of claim 1 wherein said hydrocarbon comprises at least about 50% methane by volume.

14. The method of claim 1 comprising adding a combustible gas to said reactant gas mixture sufficient to initiate a net catalytic partial oxidation reaction.

15. The method of claim 1 comprising maintaining autothermal catalytic partial oxidation promoting conditions.

16. The method of claim 15 wherein maintaining autothermal catalytic partial oxidation reaction promoting conditions comprises:

regulating the relative amounts of hydrocarbon and O₂ in said reactant gas mixture,

regulating the preheating of said reactant gas mixture,

regulating the operating pressure of said reactor,

regulating the space velocity of said reactant gas mixture, and

regulating the hydrocarbon composition of said hydrocarbon containing gas.

17. The method of claim 16 wherein said step of maintaining autothermal catalytic partial oxidation reaction promoting conditions includes keeping the temperature of the catalyst in the range of 600-1,600°

C.

18. The method of claim 1 wherein said catalyst comprises a metal or metal oxide promoter chosen from the group consisting of Cr, Mn, Rh, Pt, La and Ce, and oxides thereof.

19. The method of claim 18 wherein said catalyst comprises:

0.05-25 wt % Mg (wt % relative to total weight of catalyst)

1.0-5 atomic ratio of Ni;

0.0001-0.01 atomic ratio of Pt (atomic ratio relative to the amount of Mg); and

0.05-1.0 atomic ratio of Cr (atomic ratio relative to the amount of Mg), deposited on a refractory support.

20. The method of claim 19 wherein said catalyst comprises:

3-8 wt % Mg (wt % relative to total weight of catalyst)

1.0-3.0 atomic ratio of Ni;

0.0001-0.005 atomic ratio of Pt (atomic ratio relative to the amount of Mg); and

0.05-0.5 atomic ratio of Cr (atomic ratio relative to the amount of Mg);

deposited on a refractory support.

21. The method of claim 18 wherein said catalyst comprises 0.0016 atomic ratio of Pt, 0.10 atomic ratio of Cr, 1.36 atomic ratio of Ni and 3.9 wt % Mg disposed on a refractory monolith support.

22. The method of claim 18 wherein said catalyst comprises about 2.7 wt % Mg, about 9.0 wt % Ni and about 2.5 wt % Mn.

23. The method of claim 18 wherein said catalyst comprises about 2.8 wt % Mg, about 9.2 wt % Ni and about 2.7 wt % La.

24. The method of claim 18 wherein said catalyst comprises about 8.8 wt % Mg, about 4.3 wt % Ni and about 0.05 wt % Pt.

25. The method of claim 18 wherein said catalyst comprises about 4.1 wt % Mg, about 10.2 wt % Ni, about 1.5 wt % Mn and about 0.05 wt % Pt.

26. The method of claim 18 wherein said catalyst comprises about 4.0 wt % Mg, about 10.6 wt % Ni, about 1.4 wt % La and about 0.05 wt % Pt.

27. The method of claim 18 wherein said catalyst comprises about 4.0 wt % Mg, about 11.3 wt % Ni, about 1.5 wt % Ce and about 0.05 wt % Pt.

28. The method of claim 1 wherein said catalyst support comprises a refractory material chosen from the group consisting of zirconia, MgO stabilized zirconia, zirconia stabilized alumina, yttrium stabilized zirconia, calcium stabilized zirconia, alumina, cordierite, mullite, titania, silica, magnesia, niobia, vanadia, nitrides and carbides, and combinations of any of those materials.

29. The method of claim 1 wherein said support comprises a monolith.

30. The method of claim 1 wherein said support comprises a plurality of discrete structures.

31. The method of claim 30 wherein the longest characteristic dimension or each said discrete structure is in the range of 50 microns to 6 mm in length.

32. The method of claim 1 wherein said catalyst is prepared by a process comprising:

depositing MgO or a precursor thereof on a refractory support;

depositing nickel and/or nickel oxide, or a precursor thereof, on said MgO;

forming a Ni and Mg-containing solid solution on said refractory support;

depositing at least one promoter, or precursor thereof, on said solid solution; and

stabilizing said catalyst.

33. The method of claim 1 wherein said stabilizing comprises thermally conditioning said catalyst or an intermediate preparation stage thereof.

34. The method of claim 33 wherein said thermally conditioning comprises subjecting said catalyst or intermediate to at least two heat treatments, each said treatment including a defined heating and cooling program.

35. The method of claim 34 wherein said at least two heat treatments comprise heating a catalyst intermediate at a predetermined heating rate up to a first temperature and heating a catalyst intermediate at a predetermined heating rate from said first temperature to a second temperature, and, optionally, applying at least one additional heat treatment to said catalyst or intermediate thereof.

36. The method of claim 35 wherein said catalyst preparation process comprises a second or final heat treatment that includes heating said catalyst to a temperature in the range of about 500-1,700°

C.

37. The method of claim 35 wherein said first temperature is sufficient to decompose said MgO precursor compound to form MgO.

38. The method of claim 35 wherein said first temperature is in the range of about 125°

C.-325°

C. and said second temperature is in the range of about 300°

C.-900°

C.

39. The method of claim 34 wherein said defined heating and cooling program includes a heating rate of about 0.1-50°

C./min.

40. The method of claim 39 wherein said heating rate is about 1-5°

C./min.

41. The method of claim 34 wherein said defined heating and cooling program includes a holding time of about 30-1,440 min at a defined temperature.

42. A syngas catalyst prepared by a process comprising:

impregnating a refractory metal oxide support with a decomposable magnesium oxide precursor compound;

thermally conditioning said magnesium impregnated support such that said magnesium oxide precursor compound decomposes and a magnesium oxide impregnated support is obtained;

impregnating said magnesium impregnated support with a decomposable nickel and/or nickel oxide precursor compound to provide a nickel and magnesium containing intermediate;

thermally conditioning said nickel and magnesium containing intermediate such that said nickel and/or nickel oxide precursor compound decomposes and a nickel and/or nickel oxide, magnesium oxide containing intermediate is obtained;

impregnating said nickel and/or nickel oxide, magnesium oxide containing intermediate with at least one decomposable promoter precursor compound, said promoter chosen from the group consisting of Cr, Mn, Mo, W, Sn, Re, La, Ce, Sm, Yb, Lu, Bi, Sb, In and P, to provide a promoter-1, nickel and/or nickel oxide, magnesium oxide containing intermediate;

thermally conditioning said promoter-1, nickel and/or nickel oxide, magnesium oxide containing intermediate;

optionally, impregnating said promoter-1, nickel and/or nickel oxide, magnesium oxide containing intermediate with another decomposable promoter precursor compound, said other promoter chosen from the group consisting of Pt, Rh, Ru, Ir and Pd, to provide a promoter-2, promoter-1, nickel and/or nickel oxide, magnesium oxide containing intermediate, and thermally conditioning said promoter-2, promoter-1, nickel and/or nickel oxide, magnesium oxide containing intermediate; and

optionally, reducing said catalyst,

to provide a catalyst having activity for catalyzing the partial oxidation of methane to form CO and H₂.

43. The catalyst of claim 42 wherein said step of impregnating a refractory metal oxide support with a solution of a decomposable magnesium oxide precursor compound comprises adding an aqueous solution of a magnesium salt to said refractory metal oxide support at about 70°

C. and drying said magnesium impregnated support at about 70°

C. for about 2 hours.

44. The catalyst of claim 42 wherein said step of thermally conditioning said magnesium impregnated support or said nickel and magnesium containing intermediate comprises heat treating in air according to the following schedule:

at a heating rate of about 5°

C./min ramp up to about 125°

C. and hold at about 125°

C. for about 1 hour;

at a heating rate of about 5°

C./min ramp up to about 400°

C. and hold at about 400°

C. for about 1 hour;

at a heating rate of about 5°

C./min ramp up to about 800°

C. and hold at about 400°

C. for about 1 hour;

at a heating rate of about 5°

C./min ramp up to about 1000°

C. and hold at about 900°

C. for about 3 hours; and

at a cooling rate of about 10°

C./min ramp down to room temperature.

45. The catalyst of claim 42 wherein said step of thermally conditioning said promoter-1, nickel and/or nickel oxide, magnesium oxide containing intermediate comprises:

heat treating in air according to the following schedule;

at a heating rate of about 5°

C./min ramp up to about 125°

C. and hold at about 125°

C. for about 1 hour;

at a heating rate of about 5°

C./min ramp up to about 250°

C. and hold at about 250°

C. for about 1 hour;

at a heating rate of about 5°

C./min ramp up to about 500°

C. and hold at about 500°

C. for about 3 hours; and

cooling said promoter-1, nickel and/or nickel oxide, magnesium oxide containing intermediate at a cooling rate of about 10°

C./min ramp down to room temperature.

46. The catalyst of claim 42 wherein said optional step of impregnating said promoter-1, nickel and/or nickel oxide, magnesium oxide containing intermediate with another decomposable promoter precursor compound to provide a promoter-2, promoter-1, nickel and/or nickel oxide, magnesium oxide containing intermediate comprises adding an aqueous solution of said decomposable promoter precursor compound to said promoter-1, nickel and/or nickel oxide, magnesium oxide containing intermediate at about 70°

C. and drying said promoter-2 impregnated promoter-1, nickel and/or nickel oxide, magnesium oxide containing intermediate at about 70°

C. for about 2 hours.

47. The catalyst of claim 46 wherein said step of thermally conditioning said promoter-2, promoter-1, nickel and/or nickel oxide, magnesium oxide containing intermediate comprises:

heat treating in air according to the following schedule;

at a heating rate of about 5°

C./min ramp up to about 125°

C. and hold at about 125°

C. for about 1 hour;

at a heating rate of about 5°

C./min ramp up to about 250°

C. and hold at about 250°

C. for about 1 hour;

at a heating rate of about 5°

C./min ramp up to about 500°

C. and hold at about 500°

C. for about 3 hours; and

cooling said promoter-2, promoter-1, nickel and/or nickel oxide, magnesium oxide containing intermediate at a cooling rate of about 10°

C./min ramp down to room temperature.

48. The catalyst of claim 42 wherein said method includes:

mixing together;

at least one decomposable promoter-1 precursor compound, said promoter-1 chosen from the group consisting of Cr, Mn, Mo, W, Sn, Re, La, Ce, Sm, Yb, Lu, Bi, Sb, In and P, and oxides thereof, and

at least one decomposable promoter-2 precursor compound, said promoter-2 chosen from the group consisting of Pt, Rh, Ru, Ir and Pd, to provide a promoter-1 and promoter-2 precursors mixture; and

impregnating said nickel and/or nickel oxide, magnesium oxide containing intermediate with said promoter-1 and promoter-2 precursors mixture; and

thermally conditioning said promoter-1 and promoter-2 precursors impregnated nickel and/or nickel oxide, magnesium oxide containing intermediate.

49. The catalyst of claim 42 wherein said reducing comprises passing an approximately 1:

1 (vol/vol) stream of N₂;

H₂ over said catalyst or a catalyst intermediate at about 0.3 standard liter per minute (SLPM) measured at 0°

C. and 1 atm pressure, according to the following schedule;

at a heating rate of about 3°

C./min, ramp up to about 125°

C. and hold at about 125°

C. for about 0.5 hour;

at a heating rate of about 3°

C./min, ramp up to about 700°

C. and hold at about 700°

C. for about 3 hours; and

at a cooling rate of about 5°

C./min, ramp down to room temperature.

50. The catalyst of claim 42 wherein said reducing comprises contacting the catalyst with a hydrogen containing gas at a temperature in excess of 200°

C.