Process for producing high quality pyrolysis oil from biomass

Abstract

This invention relates to a process to utilize a torrefaction pretreatment step for biomass pyrolysis process. This pretreatment improves the quality of the pyrolysis oil by reducing acidity. The inventive process shows that as a pretreatment to pyrolysis, resulting pyrolysis oil obtained from torrefied biomass has approximately 25% lower acetic acid than that from untorrefied biomass pyrolysis oil.

1 . A process for producing pyrolysis oil product from biomass comprising at least the following steps:
 a) a step of subjecting a biomass feedstock to a thermal treatment in a reactor A under a torrefaction reaction condition to produce an torrefied biomass feedstock;   b) a step of pyrolyzing said torrefied biomass feedstock in a reactor B under a pyrolysis reaction condition to form a pyrolysis oil product,   wherein said torrefaction reaction conditions includes a temperature ranging from 180° C. to 350° C., a pressure ranging from 11 psia to 500 psia, and a residence time ranging from 1 minute to 24 hours,   wherein said pyrolysis reaction conditions includes a temperature ranging from 375° C. to 700° C., a pressure ranging from 0.1 psia to 1000 psia, and a residence time ranging from 0.1 to 200 second, and   wherein said pyrolysis oil product has a TAN number between 80 and 200.   
     
     
         2 . The process of  claim 1 ,
 wherein said torrefaction reaction conditions includes a temperature ranging from 220° C. to 280° C., a pressure ranging from 11 psia to 30 psia, and a residence time ranging from 5 to 20 minutes,   wherein said pyrolysis reaction conditions includes a temperature ranging from 425° C. to 525° C., a pressure ranging from atmospheric pressure to 300 psia., and a residence time ranging from 0.5 to 2 seconds, and   wherein said pyrolysis oil product has a TAN number between 20 and 50.   
     
     
         3 . The process either  claim 1  or  2 , wherein said torrefaction reaction is carried out in said reactor A selected from a group consisting of an augers reactor, an ablative reactor, a rotating cones reactor, a fluidized-bed reactor, an entrained-flow reactor, a vacuum moving-bed reactor, a transported-bed reactor, and a fixed-bed reactor. 
     
     
         4 . The process either  claim 1  or  2 , wherein said pyrolysis reaction is carried out in said reactor B selected from a group consisting of an auger reactor, an ablative reactor, a bubbling fluidized bed reactor, a circulating fluidized bed/transport reactor, a rotating cone pyrolyzer, and a vacuum pyrolyzer. 
     
     
         5 . The process either  claim 1  or  2 , wherein said torrefaction reaction is carried out in the presence of a catalytic material selected from a group consisting acid catalysts, solid base catalysts, silica catalysts, silica-alumina catalysts, Group B metal oxide catalysts, pyrolytic char and any combination thereof. 
     
     
         6 . The process either  claim 1  or  2 , wherein said torrefaction reaction is carried out in the presence of a catalytic material selected from a group consisting ZSM5, Hydrotalcite, Diatomite, Kaolin, Ammonium Molybdate, pyrolytic char and any combination thereof. 
     
     
         7 . The process either  claim 1  or  2 , wherein said pyrolysis reaction is carried out in the presence of a catalytic material selected from a group consisting acid catalyst, solid base catalyst, silica catalyst, silica-alumina catalyst, Group B metal oxide catalyst, pyrolytic char and any combination thereof. 
     
     
         8 . The process either  claim 1  or  2 , wherein said pyrolysis reaction is carried out in the presence of a catalytic material selected from a group consisting ZSM5, Hydrotalcite, Diatomite, Kaolin, Ammonium Molybdate, pyrolytic char and any combination thereof. 
     
     
         9 . The process of either  claim 1  or  2 , wherein said torrefaction reaction is carried out in the absence of diatomic oxygen in an inert gas atmosphere comprising nitrogen, argon, steam or carbon oxide. 
     
     
         10 . The process of either  claim 1  or  2 , wherein said torrefaction reaction is carried out in a reducing gas atmosphere. 
     
     
         11 . The process of  claim 10 , wherein said reducing gas atmosphere comprises carbon monoxide. 
     
     
         12 . The process of either  claim 1  or  2 , wherein said torrefaction reaction is carried out with a reactant comprising hydrogen or ammonia. 
     
     
         13 . The process of either  claim 1  or  2 , wherein said biomass feedstock is selected from the group consisting of, wood, paper, crops, animal and plant fats, biological waste, algae and mixture thereof. 
     
     
         14 . The process of  claim 1 , wherein said torrefaction reaction conditions includes a temperature ranging from 180° C. to 350° C., a pressure ranging from 0.1 psia to 500 psia, and a residence time ranging from 1 min to 24 hours. 
     
     
         15 . A pyrolysis oil produced by a method according to  claim 1 . 
     
     
         16 . A pyrolysis oil produced by a method according to  claim 2 .