Processes for producing low acid biomass-derived pyrolysis oils

Abstract

Processes for producing a low acid biomass-derived pyrolysis oil are provided that include pre-treating a biomass-derived pyrolysis oil to form a treated acid-containing biomass-derived pyrolysis oil. The processes also include esterifying the treated acid-containing biomass-derived pyrolysis oil in the presence of supercritical alcohol and a catalyst composition to form the low-acid biomass-derived pyrolysis oil, the catalyst composition comprising a material selected from the group consisting of an unsupported solid acid catalyst, an unsupported solid base catalyst, and a catalytic metal dispersed on a metal oxide support.

1 . A process for producing a low-acid biomass-derived pyrolysis oil comprising:
 pre-treating a biomass-derived pyrolysis oil to form a treated acid-containing biomass-derived pyrolysis oil; and   esterifying the treated acid-containing biomass-derived pyrolysis oil in the presence of supercritical alcohol and a catalyst composition to form the low-acid biomass-derived pyrolysis oil, the catalyst composition comprising a material selected from the group consisting of an unsupported solid acid catalyst, an unsupported solid base catalyst, and a catalytic metal dispersed on a metal oxide support, wherein:   the unsupported solid acid catalyst comprises a material selected from the group consisting of a molecular sieve and a Group V metal oxide,   the molecular sieve comprises a material selected from the group consisting of zeolite and MCM 41,   the unsupported solid base catalyst comprises a material selected from the group consisting of an alkaline earth metal exchanged molecular sieve, calcium oxide (CaO), magnesium oxide (MgO), and silicon oxide (SiO 2 ),   the catalytic metal comprises a metal selected from the group consisting of noble metals, non-noble metals, and combinations thereof, and   the metal oxide support comprises a metal oxide selected from the group consisting of a Group IV metal oxide, a Group V metal oxide, a Group IIIA metal oxide, and combinations thereof.   
     
     
         2 . The process of  claim 1 , wherein the zeolite is selected from the group consisting of BEA-type zeolite, zeolite X, zeolite Y, zeolite ZSM 5, and zeolite ZSM 12. 
     
     
         3 . The process of  claim 1 , wherein the Group V metal oxide comprises niobium oxide (Nb 2 O 5 ). 
     
     
         4 . The process of  claim 1 , wherein the alkaline earth metal exchanged molecular sieve comprises a molecular sieve selected from the group consisting of barium exchanged molecular sieve and calcium exchanged molecular sieve. 
     
     
         5 . The process of  claim 1 , wherein the metal on the metal oxide support comprises a non-noble metal comprising nickel. 
     
     
         6 . The process of  claim 5 , wherein the catalytic metal dispersed on the metal oxide support comprises the non-noble metal and a material comprising elements selected from the group consisting of molybdenum, cobalt, tungsten, and combinations thereof. 
     
     
         7 . The process of  claim 1 , wherein the catalytic metal on the metal oxide support comprises a composition selected from the group consisting of: (a) about 0.5 wt % to about 3.5 wt % of nickel and about 5 wt % to about 20 wt % of molybdenum, (b) about 0.1 wt % to about 1.5 wt % of nickel, about 0.5 wt % to about 3.5 wt % of cobalt, and about 5 wt % to about 20 wt % of molybdenum, and (c) about 0.5 wt % to about 3.5 wt % of nickel and about 5 wt % to about 20 wt % of tungsten. 
     
     
         8 . The process of  claim 1 , wherein the catalytic metal on the metal oxide support comprises a non-noble metal comprising cobalt. 
     
     
         9 . The process of  claim 1 , wherein the metal oxide support comprises about 0.5 wt % to about 3.5 wt % of cobalt, about 5 wt % to about 20 wt % of molybdenum. 
     
     
         10 . The process of  claim 1 , wherein the catalytic metal on the metal oxide support comprises a noble metal selected from the group consisting of platinum, rhodium, ruthenium, palladium, iridium, and combinations thereof. 
     
     
         11 . The process of  claim 1 , wherein the metal oxide support comprises a metal oxide selected from the group consisting of titanium oxide (TiO 2 ), zirconium oxide (ZrO 2 ), niobium oxide (Nb 2 O 5 ), silicon oxide (SiO 2 ), and combinations thereof. 
     
     
         12 . The process of  claim 1 , wherein the alcohol comprises an aliphatic alcohol selected from a group consisting of methanol, ethanol, propanol, and butanol. 
     
     
         13 . The process of  claim 1 , wherein the step of esterifying the treated acid-containing biomass-derived pyrolysis oil comprises esterifying at a temperature in a range of about 180° C. to about 290° C. at a pressure of about 4.41 MPa (640 psi) to about 8.00 MPa (1160 psi). 
     
     
         14 . The process of  claim 1 , wherein the step of esterifying the treated acid-containing biomass-derived pyrolysis oil comprises esterifying for a residence time in a range of about 1 hour to about 3 hours. 
     
     
         15 . The process of  claim 1 , wherein the step of esterifying the treated acid-containing biomass-derived pyrolysis oil comprises subjecting the treated acid-containing biomass-derived pyrolysis oil to esterification in the absence of gas. 
     
     
         16 . The process of  claim 1 , wherein the step of pre-treating the biomass-derived pyrolysis oil comprises subjecting the biomass-derived pyrolysis oil to a metal-reduction ion-exchange process. 
     
     
         17 . The process of  claim 1 , wherein the step of pre-treating the biomass-derived pyrolysis oil comprises removing solids from the biomass-derived pyrolysis oil. 
     
     
         18 . The process of  claim 1 , wherein step of pre-treating the biomass-derived pyrolysis oil comprises reducing a water content of the biomass-derived pyrolysis oil. 
     
     
         19 . The process of  claim 1 , further comprising the step of diluting the treated acid-containing biomass-derived pyrolysis oil with ethanol to form a solution of at least 30% ethanol, by weight, before the step of esterifying. 
     
     
         20 . The process of  claim 1 , wherein the step of esterifying comprises esterifying in an upflow tubular reactor. 
     
     
         21 . The process of  claim 1 , further comprising the step of distilling the low-acid biomass-derived pyrolysis oil to separate ethanol from the low-acid biomass-derived pyrolysis oil. 
     
     
         22 . A process for producing a low-acid biomass-derived pyrolysis oil comprising the steps of:
 pre-treating a biomass-derived pyrolysis oil to form a treated acid-containing biomass-derived pyrolysis oil;   diluting the treated acid-containing biomass-derived pyrolysis oil with supercritical ethanol to form a solution including at least about 30% ethanol, by weight; and   esterifying the treated acid-containing biomass-derived pyrolysis oil included in the solution in the presence of a catalyst composition and in the absence of gas in an upflow reactor to form the low-acid biomass-derived pyrolysis oil, wherein the catalyst composition comprises a noble metal support on a sulfated metal oxide.   
     
     
         23 . The process of  claim 22 , wherein the catalyst composition comprises a sulfated zirconia. 
     
     
         24 . The process of  claim 23 , wherein the noble metal comprises palladium.