Methods and systems for deoxygenating biomass-derived pyrolysis oil with a recycle column

Abstract

Methods and systems for deoxygenating a biomass-derived pyrolysis oil are provided. An exemplary method includes combining a biomass-derived pyrolysis oil stream with a heated low-molecular weight fraction low-oxygen-pyoil diluent recycle stream to form a heated diluted pyoil feed stream, which is contacted with a first deoxygenating catalyst in the presence of hydrogen at first hydroprocessing conditions effective to form a low-oxygen biomass-derived pyrolysis oil effluent. A low-molecular weight fraction low-oxygen-pyoil diluent recycle stream is formed by contacting the low-oxygen biomass-derived pyrolysis oil effluent with a fractionation column to separate a low molecular weight fraction low-oxygen-pyoil diluent recycle stream at a cutpoint of about 225° C. or less. The low-molecular weight fraction low-oxygen-pyoil diluent recycle stream is then heated prior to combination with the biomass-derived pyrolysis oil stream.

What is claimed is: 
     
         1 . A method for deoxygenating a biomass-derived pyrolysis oil, the method comprising the steps of:
 combining a biomass-derived pyrolysis oil stream with a heated low molecular weight fraction low-oxygen-pyoil diluent recycle stream to form a heated diluted pyoil feed stream that has a feed temperature of about 150° C. or greater;   contacting the heated diluted pyoil feed stream with a first deoxygenating catalyst in the presence of hydrogen at first hydroprocessing conditions effective to form a low-oxygen biomass-derived pyrolysis oil effluent;   separating the low-oxygen biomass-derived pyrolysis oil effluent to produce a low molecular weight fraction low-oxygen-pyoil diluent recycle stream, wherein the low molecular weight fraction low-oxygen-pyoil diluent recycle stream is separated from the low-oxygen biomass-derived pyrolysis oil effluent at a cutpoint of about 225° C. or less; and   heating the low molecular weight fraction low-oxygen-pyoil diluent recycle stream to form the heated low molecular weight fraction low-oxygen-pyoil diluent recycle stream.   
     
     
         2 . The method of  claim 1 , wherein the low molecular weight fraction low-oxygen-pyoil diluent recycle stream is separated from the low-oxygen biomass-derived pyrolysis oil effluent at a cutpoint of between about 190 to about 225° C. 
     
     
         3 . The method of  claim 1 , wherein the first hydroprocessing conditions include a reaction temperature of about the feed temperature. 
     
     
         4 . The method of  claim 1 , wherein heating the low molecular weight fraction low-oxygen-pyoil diluent recycle stream comprises heating to a temperature of from about 200 to about 450° C. 
     
     
         5 . The method of  claim 1 , wherein the biomass-derived pyrolysis oil stream is combined with the heated low molecular weight fraction low-oxygen-pyoil diluent recycle stream at a predetermined recycle ratio of at least about 2:1; wherein the predetermined recycle ratio is defined by a recycle mass flow rate of the heated low molecular weight fraction low-oxygen-pyoil diluent recycle stream to a pyoil mass flow rate of the biomass-derived pyrolysis oil stream. 
     
     
         6 . The method of  claim 5 , wherein the predetermined recycle ratio is from about 2:1 to about 20:1. 
     
     
         7 . The method of  claim 1 , wherein contacting the heated diluted pyoil feed stream with the first deoxygenating catalyst comprises partially deoxygenating the heated diluted pyoil feed stream, and wherein the low-oxygen biomass-derived pyrolysis oil effluent comprises a hydroprocessed organic phase that has a residual oxygen content of from about 15 to about 25 wt. % of the hydroprocessed organic phase. 
     
     
         8 . The method of  claim 1 , further comprising subjecting the low-oxygen biomass-derived pyrolysis oil effluent to a phase separation to at least reduce an amount of water in the low-oxygen biomass-derived pyrolysis oil effluent prior to separation of the low molecular weight fraction low-oxygen-pyoil diluent recycle stream. 
     
     
         9 . The method of  claim 8 , wherein the low-oxygen biomass-derived pyrolysis oil effluent is subjected to the phase separation at a temperature of about 0 to 60° C. 
     
     
         10 . The method of  claim 1 , further comprising subjecting the low molecular weight fraction low-oxygen-pyoil diluent recycle stream to a phase separation to at least reduce an amount of water in the low molecular weight fraction low-oxygen-pyoil diluent recycle stream prior to heating and combining with the biomass-derived pyrolysis oil stream. 
     
     
         11 . The method of  claim 10 , wherein the low molecular weight fraction low-oxygen-pyoil diluent recycle stream is subjected to the phase separation at a temperature of about 60 to 140° C. 
     
     
         12 . A method for deoxygenating a biomass-derived pyrolysis oil, the method comprising the steps of:
 combining a biomass-derived pyrolysis oil stream with a heated low molecular weight fraction low-oxygen-pyoil diluent recycle stream to form a heated diluted pyoil feed stream that has a feed temperature of about 150° C. or greater;   contacting the heated diluted pyoil feed stream with a first deoxygenating catalyst in the presence of hydrogen at first hydroprocessing conditions effective to form a low-oxygen biomass-derived pyrolysis oil effluent;   contacting the low-oxygen biomass-derived pyrolysis oil effluent with a fractionation column to separate the low-oxygen biomass-derived pyrolysis oil effluent into a low molecular weight fraction and a high molecular weight fraction, wherein the low molecular weight fraction and high molecular weight fraction are separated at a cutpoint of about 225° C. or less, and wherein at least a portion of the a low molecular weight fraction is routed for use as a low molecular weight fraction low-oxygen-pyoil diluent recycle stream;   separating the low-oxygen biomass-derived pyrolysis oil effluent to produce a low molecular weight fraction low-oxygen-pyoil diluent recycle stream and a high molecular weight fraction of the low-oxygen biomass-derived pyrolysis oil effluent, wherein the low molecular weight fraction low-oxygen-pyoil diluent recycle stream and high molecular weight fraction of the low-oxygen biomass-derived pyrolysis oil effluent are separated at a cutpoint of about 225° C. or less;   heating the low molecular weight fraction low-oxygen-pyoil diluent recycle stream to form the heated low molecular weight fraction low-oxygen-pyoil diluent recycle stream; and   contacting the high molecular weight fraction of the low-oxygen biomass-derived pyrolysis oil effluent with a second deoxygenating catalyst in the presence of hydrogen at second hydroprocessing conditions effective to form an ultralow-oxygen biomass-derived pyrolysis oil effluent.   
     
     
         13 . The method of  claim 12 , wherein the low molecular weight fraction low-oxygen-pyoil diluent recycle stream is separated from the low-oxygen biomass-derived pyrolysis oil effluent at a cutpoint of between about 190 to about 225° C. 
     
     
         14 . The method of  claim 12 , wherein the first hydroprocessing conditions include a reaction temperature of about the feed temperature. 
     
     
         15 . The method of  claim 12 , wherein heating the low molecular weight fraction low-oxygen-pyoil diluent recycle stream comprises heating to a temperature of from about 200 to about 450° C. 
     
     
         16 . The method of  claim 12 , wherein the biomass-derived pyrolysis oil stream is combined with the heated low molecular weight fraction low-oxygen-pyoil diluent recycle stream at a predetermined recycle ratio of at least about 2:1; wherein the predetermined recycle ratio is defined by a recycle mass flow rate of the heated low molecular weight fraction low-oxygen-pyoil diluent recycle stream to a pyoil mass flow rate of the biomass-derived pyrolysis oil stream. 
     
     
         17 . The method of  claim 12 , wherein contacting the heated diluted pyoil feed stream with the first deoxygenating catalyst comprises partially deoxygenating the heated diluted pyoil feed stream, and wherein the low-oxygen biomass-derived pyrolysis oil effluent comprises a hydroprocessed organic phase that has a residual oxygen content of from about 15 to about 25 wt. % of the hydroprocessed organic phase. 
     
     
         18 . The method of  claim 12 , further comprising subjecting the low-oxygen biomass-derived pyrolysis oil effluent to a phase separation to at least reduce an amount of water in the low-oxygen biomass-derived pyrolysis oil effluent prior to separation of the low molecular weight fraction low-oxygen-pyoil diluent recycle stream. 
     
     
         19 . The method of  claim 12 , further comprising subjecting the low molecular weight fraction low-oxygen-pyoil diluent recycle stream to a phase separation to at least reduce an amount of water in the low molecular weight fraction low-oxygen-pyoil diluent recycle stream prior to heating and combining with the biomass-derived pyrolysis oil stream. 
     
     
         20 . A system for deoxygenating a biomass-derived pyrolysis oil, the system comprising:
 a first hydroprocessing reactor configured to contain a first hydroprocessing catalyst, the first hydroprocessing reactor configured to receive a heated diluted pyoil feed stream and contact the heated diluted pyoil feed stream with the first hydroprocessing catalyst in the presence of hydrogen under first hydroprocessing conditions effective to form a low-oxygen biomass-derived pyrolysis oil effluent, wherein the heated diluted pyoil feed stream comprises a combination of a biomass-derived pyrolysis oil stream and a heated low molecular weight fraction low-oxygen-pyoil diluent recycle stream combined at a predetermined ratio;   a fractionation column configured to receive the low-oxygen biomass-derived pyrolysis oil effluent and operate under conditions such that a low molecular weight fraction low-oxygen-pyoil diluent recycle stream is separated from the low-oxygen biomass-derived pyrolysis oil effluent at a cutpoint of about 225° C. or lower; and   a heater configured to receive and heat the low molecular weight fraction low-oxygen-pyoil diluent recycle stream to form the heated low molecular weight fraction low-oxygen-pyoil diluent recycle stream.