Use of hydrogen to regenerate metal oxide hydrogen sulfide sorbents

Abstract

A process to regenerate a spent hydrogen sulfide sorbent comprised of a sorbent metal selected from Fe, Ni, Co, and Cu on a refractory oxide support using hydrogen gas. The sorbent metal component may be mono- or multi-metallic in nature, and preferably comprise Ni and/or Co. If desired, secondary metals may be incorporated to increase regeneration efficiency and/or capacity. Other additives suppress hydrocarbon cracking.

1 . A process for regenerating a hydrogen sulfide sorbent comprising: 
 providing a spent hydrogen sulfide sorbent comprised of an effective quantity of a sorbent metal selected from the group consisting of Fe, Ni, Co, Cu, and polymetallics thereof on a metal oxide support, said hydrogen sulfide sorbent having a level of sulfur defining a first cycle capacity for absorbing hydrogen sulfide; and    exposing said spent hydrogen sulfide sorbent to a gas comprising a regenerating concentration of hydrogen under conditions effective for said hydrogen to regenerate said spent hydrogen sulfide sorbent, thereby producing a regenerated sorbent.    
     
     
         2 . The process of  claim 1  wherein said sorbent metal is selected from Ni and Co.  
     
     
         3 . The process of  claim 2  wherein said conditions comprise a temperature from about 100° C. to about 700° C.  
     
     
         4 . The process of  claim 3  wherein said conditions comprise a temperature from about 250° C. to about 600° C.  
     
     
         5 . The process of  claim 2  wherein said spent hydrogen sulfide sorbent contains a regeneration rate enhancing amount of a noble metal selected from Group VIII of the Period Table of the elements, wherein said regeneration rate enhancing amount reduces said regenerated capacity by about 50% or less.  
     
     
         6 . The process of  claim 5  wherein said regeneration rate enhancing amount reduces said regenerated capacity by about 30% or less.  
     
     
         7 . The process of  claim 5  wherein the noble metal is at least one of Ir, Pt, Pd, and Rh.  
     
     
         8 . The process of  claim 7  wherein two noble metals are present.  
     
     
         9 . The process of  claim 5  wherein said regeneration rate enhancing amount ranges from about 0.01 wt. % to about 10 wt. %.  
     
     
         10 . The process of  claim 1  wherein the sorbent further comprises at least one hydrocracking suppressor metal selected from Group IB, Group IVA, and Group VIA of the Periodic Table in a suppressing quantity sufficient to suppress hydrocracking.  
     
     
         11 . The process of  claim 10  wherein said hydrocracking suppressor metal is 
 (i) at least one of Cu, Ag, Au, Sn, and Pb, and the suppressing quantity ranges from about 1 wt. % to about 10 wt. %, or  
 (ii) at least one Group VIA element, and the suppressing quantity ranges from about 0.01 wt. % to about 2 wt. %.  
 
     
     
         12 . The process of  claim 1  wherein the regenerated sorbent has a capacity for absorbing hydrogen sulfide ranging from about 5% to about 100% of the first cycle capacity.  
     
     
         13 . A desulfurization process comprising: 
 (a) contacting a hydrocarbon containing sulfur with a catalytically effective amount of a catalyst system under catalytic hydrodesulfurization conditions, the catalyst system being comprised of: 
 (i) a hydrodesulfurization catalyst containing at least one of Mo, W, Fe, Co, Ni, Pt, Pd, Ir, and Rh; and comprising at least one of:  
 (ii) a hydrogen sulfide sorbent containing at least one sorbent metal selected from Fe, Co, Ni, and Cu, on a metal oxide support, said hydrogen sulfide sorbent comprising a level of sulfur defining a first cycle capacity for absorbing hydrogen sulfide, said contacting producing at least a desulfurized product and a spent hydrogen sulfide sorbent; and then  
   (b) exposing said spent hydrogen sulfide sorbent to a gas comprising a regenerating concentration of hydrogen under conditions effective for said hydrogen to regenerate said spent hydrogen sulfide sorbent, producing a regenerated sorbent.    
     
     
         14 . The process of  claim 13  wherein said sorbent metal is selected from at least one of Ni and Co.  
     
     
         15 . The process of  claim 13  wherein the regenerating conditions include a temperature ranging from about 100° C. to about 700° C. and a pressure ranging from about 0 psia to about 3000 psia.  
     
     
         16 . The process of  claim 15  wherein the regeneration concentration of hydrogen ranges from about 10 SCF/hr/lb to about 2000 SCF/hr/lb, based on the weight of the hydrogen sulfide sorbent.  
     
     
         17 . The process of  claim 14  wherein the hydrogen is combined with at least one inert or light hydrocarbon diluent gas, wherein the hydrogen is present in a volume ranging from about 50% to about 100%, based on the total volume of hydrogen and diluent, and wherein the regenerating conditions include a temperature ranging from about 100° C. to about 700° C., at a pressure ranging from about 0 psia to about 3000 psia, for a time ranging from about 0.25 hour to about 10 hours, and a hydrogen treat gas rate of about 10 to about 2000 SCF/hr/lb, based on the weight of the hydrogen sulfide sorbent.  
     
     
         18 . The process of  claim 13  wherein the regenerated sorbent has a regenerated capacity for sulfur absorption ranging from about 5 wt. % to about 100 wt. % of the first cycle capacity.  
     
     
         19 . The process of  claim 17  wherein the hydrogen is combined with an inert diluent gas.  
     
     
         20 . The process of  claim 13  wherein the sorbent further comprises at least one hydrocracking suppressor selected from Group IB, Group IVA, and Group VIA of the Periodic Table in a suppressing quantity sufficient to suppress hydrocracking.  
     
     
         21 . The process of  claim 20  wherein the hydrocracking suppressor is 
 (i) at least one of Cu, Ag, Au, Sn, and Pb, and the suppressing quantity ranges from about 1 wt. % to about 10 wt. %, or  
 (ii) at least one Group VIA element, and the suppressing quantity ranges from about 0.01 wt. % to about 2 wt. %.  
 
     
     
         22 . The process of  claim 13  wherein the hydrogen sulfide sorbent is the regenerated sorbent.  
     
     
         23 . The process of  claim 22  wherein steps (a) and (b) are performed continuously.  
     
     
         24 . The process of  claim 13  wherein at least one of the hydrodesulfurization catalyst and the hydrogen sulfide sorbent is supported on an inorganic refractory support.  
     
     
         25 . The process of  claim 13  wherein the weight ratio of the hydrogen sulfide sorbent to the hydrodesulfurization catalyst ranges from about 0.01 to about 1000.  
     
     
         26 . The process of  claim 25  wherein the hydrodesulfurization catalyst and the hydrogen sulfide sorbent are in the form of separate particles.  
     
     
         27 . The process of  claim 25  wherein the hydrodesulfurization catalyst and the hydrogen sulfide sorbent are in the form of a composited particle.  
     
     
         28 . The process of  claim 25  wherein the catalyst system is in the form of catalyst particles, and wherein the hydrogen sulfide sorbent is impregnated with the hydrodesulfurization catalyst.  
     
     
         29 . The process of  claim 13  wherein the hydrodesulfurization catalyst contains at least one of Fe, Co, Ni, Mo, and W.  
     
     
         30 . The process of  claim 13  operated in at least one of a moving bed, a bubbling bed, a non-fluidized moving bed, a fluidized bed, a continuously stirred tank reactor, and a slurry bubble column.  
     
     
         31 . The process of  claim 30  wherein the process is a fixed bed process operated in one of 
 (i) cocurrent and  
 (ii) countercurrent mode, and wherein the catalytic hydrodesulfurization conditions include a temperature of about 40° C. to about 500° C., a pressure ranging from about 100 psig to about 3,000 psig, a treat gas rate ranging from about 50 to about 10,000 SCF/B, and a space velocity ranging from about 0.1 to about 100 V/V/Hr.