Olefin upgrading process with guard bed regeneration

Abstract

A process for the regeneration of materials used in the guard beds preceding the reactors used in an olefin conversion process which converts olefinic refinery streams to higher boiling hydrocarbon products by polymerization (oligomerization) or alkylation of aromatics including benzene. Products of the process may include olefin oligomers and alkylaromatics in the gasoline boiling range as well as alkylaromatic petrochemicals such as cumene and ethylbenzene. The process is integrated with the olefin conversion process to ensure continuous operation of the olefin conversion without sending the feedstock containing the contaminant(s) to the reactor. The process uses reaction products from the olefin conversion process to regenerate the guard bed material and so is economically attractive since it does not require the use of separate purge, regeneration feed and separation systems. A plurality of guard beds is used, each containing a material which removes catalyst poisons. The guard beds are operated on a swing system in which one or more beds is kept on stream to remove the contaminant(s) while one or more of the remaining beds is being purged or regenerated. In this way, continuity of operation is assured. The regeneration medium is a product stream from the olefin conversion process.

1 . A process for regenerating a guard bed of porous solid material used for removing contaminants including sulfur compounds from a feed stream comprising light refinery olefins passing to a reactor containing a fixed bed of a solid, porous, molecular sieve catalyst in which the feed stream is converted to a higher boiling range hydrocarbon products, which comprises desorbing contaminants from the feed which are present on the solid material by passing a stream of hydrocarbon product from the reactor over the guard bed. 
     
     
         2 . A process according to  claim 1  in which the feed stream is a stream produced by catalytic cracking of a hydrocarbon feed and comprising C3 to C4 olefins. 
     
     
         3 . A process according to  claim 1  in which the feed stream comprises C3 to C4 olefins produced by catalytic cracking of a hydrocarbon feed and aromatic compounds including benzene. 
     
     
         4 . A process according to  claim 1  in which the feed stream is passed over a fixed bed of a catalyst comprising an MWW zeolite. 
     
     
         5 . A process according to  claim 1  in which the guard bed material comprises a molecular sieve capable of reacting with contaminants in the feed stream. 
     
     
         6 . A process according to  claim 5  in which the guard bed material comprises an MWW zeolite. 
     
     
         7 . A process according to  claim 1  in which the hydrocarbon from the reactor passed over the guard bed material comprises a light paraffin. 
     
     
         8 . A process according to  claim 1  in which the hydrocarbon from the reactor passed over the guard bed material comprises alkylaromatic hydrocarbons. 
     
     
         9 . A process according to  claim 1  in which the hydrocarbon from the reactor passed over the guard bed material comprises C4-C6 hydrocarbons. 
     
     
         10 . A process according to  claim 1  in which the stream of hydrocarbon product from the reactor is passed over the guard bed at a temperature of at least 100° C. 
     
     
         11 . In a process for converting a feed stream comprising light refinery olefins and including sulfur compounds as contaminants to a gasoline boiling range hydrocarbon product, by passing the feed stream in a reactor over a fixed bed of a solid, porous, molecular sieve catalyst at an elevated temperature, the improvement which comprises the removal of contaminants from the feed stream by passing the feed stream upstream of the reactor over a fixed guard bed of solid, porous material and subsequently desorbing contaminants from the feed which are present on the solid material by passing a stream of hydrocarbon product from the reactor over the guard bed. 
     
     
         12 . A process according to  claim 1  in which the feed stream is a stream produced by catalytic cracking of a hydrocarbon feed and comprising C3 to C4 olefins. 
     
     
         13 . A process according to  claim 1  in which the feed stream comprises a stream produced by catalytic cracking of a hydrocarbon feed and comprising C3 to C4 olefins and a reformate stream comprising benzene. 
     
     
         14 . A process according to  claim 1  in which the feed stream is passed over a fixed bed of a catalyst comprising an MWW zeolite. 
     
     
         15 . A process according to  claim 1  in which the guard bed material comprises a molecular sieve capable of reacting with contaminants in the feed stream. 
     
     
         16 . A process according to  claim 5  in which the guard bed material comprises an MWW zeolite. 
     
     
         17 . A process according to  claim 1  in which the stream of hydrocarbon product from the reactor is passed over the guard bed at a temperature of at least 100° C. 
     
     
         18 . A process according to  claim 1  in which the stream of hydrocarbon product from the reactor is passed over the guard bed at a temperature of 200-300° C. 
     
     
         19 . A process according to  claim 11  in which the contaminants are removed feed stream by passing the feed stream upstream of the reactor over a fixed guard bed of the solid, porous material in the first of at least two guard bed vessels connected upstream of the reactor and to an inlet of the reactor and the contaminants are desorbed from the solid, porous material by passing a stream of hydrocarbon product from the reactor over the guard bed material contained in a second of the guard bed vessels. 
     
     
         20 . A process according to  claim 19  in which the first and second guard beds are operate in a swing system in which the first guard bed vessel is used to remove the contaminants from the feed stream while the contaminants are removed from the guard bed material in the second guard bed vessel by passing the stream of hydrocarbon product from the reactor over the guard bed material contained in the second guard bed vessel.