In-situ upgrading of biomass pyrolysis vapor using acid catalyst and alcohol

Abstract

Processes for thermal conversion of biomass are provided. The processes involve upgrading the pyrolysis vapor from a pyrolysis reactor. The steps include thermally converting a biomass feedstock in a pyrolysis reactor, recovering a pyrolysis vapor from the reactor, passing the pyrolysis vapor in contact with an acid catalyst in the presence of alcohol, and converting the resulting upgraded pyrolysis vapor into a liquid product. The resulting biooil liquid product is more refined, and the overall processes offer economic and energy efficiency.

What is claimed is: 
     
         1 . A process for the thermal conversion of biomass comprising the steps of:
 a) thermal conversion of a biomass feedstock in a pyrolysis reactor;   b) recovering a pyrolysis vapor from the reactor;   c) passing the pyrolysis vapor in contact with an acid catalyst in the presence of an alcohol to produce an upgraded pyrolysis vapor; and   d) converting the upgraded pyrolysis vapor from step c) into a liquid product.   
     
     
         2 . The process of  claim 1 , wherein the acid catalyst comprises a sulfated zirconium catalyst, a zeolite β or Nafion-SiO2 catalyst. 
     
     
         3 . The process of  claim 1 , wherein the acid catalyst comprises a zeolite β. 
     
     
         4 . The process of  claim 1 , wherein the alcohol is methanol or ethanol. 
     
     
         5 . The process of  claim 1 , wherein the alcohol is injected into a stream containing the pyrolysis vapor passed in contact with the acid catalyst. 
     
     
         6 . The process of  claim 1 , wherein the liquid product has a pH in a range of from about 2 to about 5.