Autothermal process for the production of olefins

Abstract

A process and catalyst for the partial oxidation of paraffinic hydrocarbons, such as ethane, propane, naphtha, and natural gas condensates, to olefins, such as ethylene and propylene. The process involves contacting a paraffinic hydrocarbon with oxygen in the presence of hydrogen and a catalyst under autothermal process conditions. Preheating the feed decreases oxygen consumption and increases the net hydrogen balance. The catalyst comprises a Group 8B metal, preferably, a platinum group metal, and at least one promoter selected from Groups 1B, 6B, 3A, 4A, and 5A, optionally supported on a catalytic support, such as magnesia or alumina. In preferred embodiments, the support is pretreated with a support modifier selected from Groups 1A, 2A, 3B, 4B, 5B, 6B, 1B, 3A, 4A, 5A, the rare earth lanthanides, and the actinides. A modified fluidized bed reactor is disclosed for the process.

What is claimed is:  
     
         1 . A catalyst composition comprising a Group 8B metal and at least one promoter supported on a ceramic monolith support which has been pretreated with a support modifier.  
     
     
         2 . The composition of  claim 1  wherein the Group 8B metal is a platinum group metal.  
     
     
         3 . The composition of  claim 1  wherein the platinum group metal is platinum.  
     
     
         4 . The composition of  claim 1  wherein the promoter is selected from Groups 1B, 6B, 3A, 4A, 5A, and mixtures thereof.  
     
     
         5 . The composition of  claim 1  wherein the promoter is selected from copper, tin, antimony, silver, indium, and mixtures thereof.  
     
     
         6 . The composition of  claim 1  wherein the support modifier is selected from Groups 1A, 2A, 3B, 4B, 5B, 6B, 1B, 3A, 4A, 5A, the lanthanide rare earths, and the actinide elements of the Periodic Table, and mixtures of the aforementioned elements.  
     
     
         7 . The composition of  claim 1  wherein the support modifier is selected from calcium, zirconium, tin, lanthanum, potassium, lutetium, erbium, barium, holmium, cerium, silver, and antimony.  
     
     
         8 . The composition of  claim 1  wherein the ceramic monolith is selected from silica, alumina, silica-aluminas, aluminosilicates, magnesia, magnesium aluminates, magnesium silicates, zirconia, titania, boria, zirconia toughened alumina, lithium aluminum silicates, silicon carbide, silicon nitride, and oxide-bonded silicon carbide.  
     
     
         9 . The composition of  claim 8  wherein the ceramic monolith comprises from 65 to 100 weight percent alpha alumina or gamma alumina.  
     
     
         10 . The composition of  claim 1  wherein the support is in the form of a foam, a fiber, or a pellet.  
     
     
         11 . The composition of  claim 10  wherein the ceramic monolith comprises a foam having from 5 to 100 pores per linear inch (2 to 40 pores per linear cm) and a surface area greater than 0.001 m 2 /g and less than 10 m 2 /g.  
     
     
         12 . The composition of  claim 10  wherein the ceramic monolith is in the form of a fiber having a diameter greater than 1 micron and less than 20 microns, and a surface area greater than 0.001 m 2 /g and less than 1 m 2 /g.  
     
     
         13 . The composition of  claim 10  wherein the ceramic monolith is in the form of pellets having a size between 30 and 1,000 microns.  
     
     
         14 . The composition of  claim 1  which is prepared by a process comprising (a) contacting a ceramic support with a support modifier to form a pretreated support, (b) optionally, calcining or reducing the pretreated support, (c) depositing onto the pretreated support a Group 8B metal and at least one promoter, (d) optionally, calcining the metal loaded support, and (e) reducing the support with a reducing agent under conditions sufficient to prepare the catalyst composition.  
     
     
         15 . The composition of  claim 1  wherein the Group 8B metal is platinum; the promoter is selected from copper, tin, antimony, silver, indium, and mixtures thereof; the support is selected from alumina, magnesia, and mixtures thereof; and the modifier is selected from calcium, zirconium, tin, lanthanum, potassium, lutetium, erbium, barium, holmium, cerium, silver, and antimony.  
     
     
         16 . The composition of  claim 1  wherein the Group 8B metal is platinum; the promoter is selected from tin, copper, and mixtures thereof; the support is selected from alumina, magnesia, and mixtures thereof; and the modifier is selected from tin, lanthanum, and mixtures thereof.