Method of producing an upgraded bio-oil

Abstract

A method of producing an upgraded bio-oil from a wet biomass that includes heating the wet biomass at a first temperature and a first pressure for a time period ranging from 10 to 200 minutes to form a crude bio-oil. The first temperature ranges from 200 to 400° C. and the first pressure ranges from 0.1 to 25 MPa, with the proviso that at least a portion of the water present in the wet biomass remains in a liquid phase throughout the step of heating to form the crude bio-oil, and the first temperature and pressure are below super-critical conditions for water. The method also includes heating the crude bio-oil and the water at a second temperature and a second pressure to form the upgraded bio-oil. Some water remains in the liquid phase or in a super-critical fluid phase throughout the step of heating to form the upgraded bio-oil.

What is claimed is: 
     
         1 . A method of producing an upgraded bio-oil from a wet biomass, the method comprising:
 providing the wet biomass comprising water and biomass solids;   heating the wet biomass at a first temperature and a first pressure for a time period ranging from 10 to 200 minutes to form a crude bio-oil, with the first temperature ranging from 200 to 400° C. and the first pressure ranging from 0.1 to 25 MPa, with the proviso that at least a portion of the water present in the wet biomass remains in a liquid phase throughout the step of heating to form the crude bio-oil, and the first temperature and first pressure are below super-critical conditions of water; and   heating the crude bio-oil and water at a second temperature and a second pressure for a time period of at least 30 minutes to form the upgraded bio-oil, with the proviso that at least a portion of the water remains in the liquid phase or in a super-critical fluid phase throughout the step of heating to form the upgraded bio-oil, and   wherein the second temperature is greater than the first temperature and is at least 300° C.   
     
     
         2 . The method of  claim 1 , wherein the wet biomass comprises at least 70 wt. % water based on the total weight of the wet biomass. 
     
     
         3 . The method of  claim 2 , wherein the wet biomass comprises algae having a lipid content ranging from 20 to 80 wt. % based on the total weight of the biomass solids. 
     
     
         4 . The method of  claim 1 , wherein the second temperature and the second pressure are within super-critical conditions. 
     
     
         5 . The method of  claim 1 , wherein the step of heating the wet biomass is conducted in the presence of a first catalyst. 
     
     
         6 . The method of  claim 5 , wherein the first catalyst comprises a heterogeneous catalyst selected from the group consisting of Pd/C, Pt/C, Ru/C, Ni/SiO 2 —Al 2 O 3 , sulfided CoMo/γ-Al 2 O 3 , zeolite, activated carbon, and combinations thereof. 
     
     
         7 . The method of  claim 5 , wherein the step of heating the crude bio-oil and water is conducted in the presence of the first catalyst. 
     
     
         8 . The method of  claim 5 , wherein the step of heating the crude bio-oil and water is conducted in the presence of a second catalyst selected from the group consisting of Pd/C, Pt/C, Ru/C, Ni/SiO 2 —Al 2 O 3 , sulfided CoMo/γ-Al 2 O 3 , zeolite, activated carbon, and combinations thereof, wherein the first catalyst is different from the second catalyst. 
     
     
         9 . The method of  claim 1 , wherein the step of heating the wet biomass is conducted in a reducing atmosphere. 
     
     
         10 . The method of  claim 1 , wherein the step of heating the wet biomass is conducted in an inert atmosphere. 
     
     
         11 . The method of  claim 1 , wherein the step of heating the crude bio-oil and water is conducted in an inert atmosphere. 
     
     
         12 . The method of  claim 1 , wherein the step of heating the crude bio-oil and water is conducted in a reducing atmosphere. 
     
     
         13 . The method of  claim 1 , wherein the crude bio-oil comprises an amount of carbon ranging from 50 to 80 wt. % of the crude bio-oil, an amount of hydrogen ranging from 1 to 20 wt. % of the crude bio-oil, an amount of oxygen ranging from 5 to 20 wt. % of the crude bio-oil, an amount of nitrogen ranging from 1 to 15 wt. % of the crude bio-oil, and an amount of sulfur ranging from 0 to 5 wt. % of the crude bio-oil. 
     
     
         14 . The method of  claim 1 , wherein the upgraded bio-oil comprises an amount of carbon ranging from 70 to 90 wt. % of the crude bio-oil, an amount of hydrogen ranging from 1 to 20 wt. % of the crude bio-oil, an amount of oxygen ranging from 1 to 15 wt. % of the crude bio-oil, an amount of nitrogen ranging from 1 to 15 wt. % of the crude bio-oil, and an amount of sulfur less than 1 wt. % of the crude bio-oil. 
     
     
         15 . The method of  claim 1 , wherein the step of heating the wet biomass is conducted for a duration ranging from 55 to 100 minutes and wherein the step of heating the crude bio-oil and water is conducted for a duration ranging from 60 to 300 minutes. 
     
     
         16 . An upgraded bio-oil obtained from the refinement of crude bio-oil produced by the hydrothermal liquefaction of wet biomass, the upgraded bio-oil comprising:
 carbon in the amount ranging from 70 to 90 wt. %;   hydrogen in an amount ranging from 1 to 20 wt. %;   oxygen in an amount ranging from 1 to 15 wt. %;   nitrogen in an amount ranging from 1 to 15 wt. %;   sulfur in an amount of less than 1 wt. %, all based on the total weight of the upgraded bio-oil, with the proviso that the heating value of the upgraded bio-oil ranges from 35 to 55 MJ/kg.   
     
     
         17 . A method of producing an upgraded bio-oil from a wet biomass using hydrothermal liquefaction, the method comprising:
 providing the wet biomass comprising at least 70 wt. % water and less than 30 wt. % biomass solids based on the total weight of the wet biomass;   heating the wet biomass at a first temperature and a first pressure for a time period ranging from 10 to 200 minutes to form a crude bio-oil, with the first temperature ranging from 200 to 400° C. and the first pressure ranging from 0.1 to 25 MPa, with the proviso that at least a portion of the water present in the wet biomass remains in a liquid phase throughout the step of heating to form the crude bio-oil, and the first temperature and pressure are below super-critical conditions for the water; and   heating the crude bio-oil and the water at a second temperature and a second pressure for a time period of at least 30 minutes to form the upgraded bio-oil, with the proviso that at least a portion of the water remains in a liquid phase or in a super-critical fluid phase throughout the step of heating to form the upgraded bio-oil, and   wherein the second temperature is greater than the first temperature and at least 300° C.   
     
     
         18 . The method of  claim 17 , wherein the upgraded bio-oil comprises an amount of carbon ranging from 70 to 90 wt. % of the crude bio-oil, an amount of hydrogen ranging from 1 to 20 wt. % of the crude bio-oil, an amount of oxygen ranging from 1 to 15 wt. % of the crude bio-oil, an amount of nitrogen ranging from 1 to 15 wt. % of the crude bio-oil, and an amount of sulfur less than 1 wt. % of the crude bio-oil. 
     
     
         19 . The method of  claim 17 , wherein the step of heating the wet biomass is conducted in the presence of a first catalyst comprising a heterogeneous catalyst selected from the group consisting of Pd/C, Pt/C, Ru/C, Ni/SiO 2 —Al 2 O 3 , sulfided CoMo/y-Al 2 O 3 , zeolite, activated carbon, and combinations thereof. 
     
     
         20 . The method of  claim 17 , wherein the step of heating the wet biomass is conducted in a reducing atmosphere.