Method for upgrading bio-oil using supercritical alcohols and upgraded bio-oil by the method

Abstract

Provided herein is a method for upgrading a bio-oil using a supercritical alcohol, and the bio-oil upgraded by the method, the method including removing oxygen existing in the molecule of the bio-oil using the supercritical state alcohol as a solvent and reacting the bio-oil and the alcohol solvent at supercritical state so as to increase the energy content, removing organic acids that increase the acidity of the bio-oil including formic acid and acetic acid or converting the organic acids to other materials so as to reduce the acidity, and converting hydrophilic materials in the bio-oil to hydrophobic materials so as to reduce the moisture content, and increasing the pH of the bio-oil to reduce the corrosiveness, thereby providing the effectiveness in upgrading a bio-oil.

What is claimed is: 
     
         1 . A method for upgrading a bio-oil using a supercritical alcohol, the method comprising:
 mixing the bio-oil and an alcohol solvent; and   upgrading the bio-oil by reacting the bio-oil and the alcohol at a supercritical state of the alcohol.   
     
     
         2 . The method according to  claim 1 ,
 further comprising separating and collecting a product of the reaction, after the upgrading.   
     
     
         3 . The method according to  claim 1 ,
 wherein the mixing comprises additionally mixing an additive.   
     
     
         4 . The method according to  claim 1 ,
 wherein a raw material of the bio-oil include at least one of lignocellulosic biomass, herbaceous biomass, fine algae, and large algae.   
     
     
         5 . The method according to  claim 1 ,
 wherein the bio-oil is in a liquid phase form produced by thermos-chemical conversion process.   
     
     
         6 . The method according to  claim 1 ,
 wherein the bio-oil has a moisture content of 2 to 40 weight %.   
     
     
         7 . The method according to  claim 1 ,
 wherein the alcohol solvent includes at least one of methanol, ethanol, propanol, isopropylalcohol, butanol, isobutanol, 2-butanol, tert-butanol, n-pentanol, isopentyl alcohol, 2-methyl-1-butanol, neopentyl alcohol, diethyl carbinol, methyl propyl carbinol, methyl isopropyl carbinol, dimethyl ethyl carbinol, 1-hexanol, 2-hexanol, 3-hexanol, 2-methyl-1-pentanol, 3-methyl-1-pentanol, 4-methyl-1-pentanol, 2-methyl-2-pentanol, 3-methyl-2-pentanol, 4-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-3-pentanol, 2,2-dimethyl-1-butanol, 2,3-dimethyl-1-butanol, 2,3-dimethyl-2-butanol, 3,3-dimethyl-1-butanol, 2-ethyl-1-butanol, 1-heptanol, 2-heptanol, 3-heptanol, and 4-heptanol.   
     
     
         8 . The method according to  claim 1 ,
 wherein the mixing includes mixing 0.1 to 60 weight % of the bio-oil, based on a total sum of the alcohol solvent and the bio-oil.   
     
     
         9 . The method according to  claim 3 ,
 wherein the additive includes at least one of LiOH, NaOH, KOH, RbOH, Li 2 CO 3 , Na 2 CO 3 , K 2 CO 3 , Mg(OH) 2 , Ca(OH) 2 , Sr(OH) 2 , MgCO 3 , CaCO 3 , SrCO 3 , HCl, HNO 3 , H 3 PO 4 , H 2 SO 4 , H 3 BO 3 , HF, H 2 CO 3 , HCOOH, CH 3 COOH, CH 3 CH 2 COOH, CH 3 CH 2 CH 2 COOH, C 2 H 4 OHCOOH, and C 6 H 5 COOH.   
     
     
         10 . The method according to  claim 1 ,
 wherein the upgrading includes upgrading the bio-oil at a reaction temperature of 250 to 600° C., and a reaction pressure of 30 to 700 bar.   
     
     
         11 . The method according to  claim 1 ,
 wherein the alcohol solvents comprises methanol (critical temperature=239° C.; critical pressure=81 bar), ethanol (critical temperature=241° C.; critical pressure=63 bar), propanol (critical temperature=264 ° C.; critical pressure=52 bar), isopropylalcohol (critical temperature=307° C.; critical pressure=41 bar), butanol (critical temperature=289° C.; critical pressure=45 bar), isobutanol (critical temperature=275° C.; critical pressure=45 bar), 2-butanol (critical temperature=263° C.; critical pressure=42 bar), tert-butanol (critical temperature=233° C.; critical pressure=40 bar), n-pentanol (critical temperature=307° C.; critical pressure=39 bar), isopentyl alcohol (critical temperature=306° C.; critical pressure=39 bar), 2-methyl-1-butanol (critical temperature=302° C.; critical pressure=39 bar), neopentyl alcohol (critical temperature=276° C.; critical pressure=40 bar), diethyl carbinol (critical temperature=286° C.; critical pressure=39 bar), methyl propyl carbinol (critical temperature=287° C.; critical pressure=37 bar), methyl isopropyl carbinol (critical temperature=283° C.; critical pressure=39 bar), dimethyl ethyl carbinol (critical temperature=271° C.; critical pressure=37 bar), 1-hexanol (critical temperature=337° C.; critical pressure=34 bar), 2-hexanol (critical temperature=310° C.; critical pressure=33 bar), 3-hexanol (critical temperature=309° C.; critical pressure=34 bar), 2-methyl-1-pentanol (critical temperature=331° C.; critical pressure=35 bar), 3-methyl-1-pentanol (critical temperature=387° C.; critical pressure=30 bar), 4-methyl-1-pentanol (critical temperature=330° C.; critical pressure=30 bar), 2-methyl-2-pentanol (critical temperature =286° C.; critical pressure =36 bar), 3-methyl-2-pentanol (critical temperature=333° C.; critical pressure=36 bar), 4-methyl-2-pentanol (critical temperature=301° C.; critical pressure=35 bar), 2-methyl-3-pentanol (critical temperature=303° C.; critical pressure=35 bar), 3-methyl-3-pentanol (critical temperature=302° C.; critical pressure=35 bar), 2,2-dimethyl-1-butanol (critical temperature=301° C.; critical pressure=35 bar), 2,3-dimethyl-1-butanol (critical temperature=331° C.; critical pressure=35 bar), 2,3-dimethyl-2-butanol (critical temperature=331° C., critical pressure=35 bar), 3,3-dimethyl-1-butanol (critical temperature =331° C.; critical pressure=35 bar), 2-ethyl-1-butanol (critical temperature=307° C.; critical pressure=34 bar), 1-heptanol (critical temperature=360° C.; critical pressure=31 bar), 2-heptanol (critical temperature=335° C.; critical pressure=30 bar), 3-heptanol (critical temperature=332° C.; critical pressure=30 bar), and 4-heptanol (critical temperature=329° C.; critical pressure=30 bar), or a combination thereof.   
     
     
         12 . A bio-oil upgraded by the method of  claim 1 . 
     
     
         13 . The upgraded bio-oil according to  claim 12 ,
 wherein the upgraded bio-oil has an oxygen content of 10 to 15 weight %, and O/C (Oxygen/Carbon) molar ratio is 0.10 to 0.16.   
     
     
         14 . The upgraded bio-oil according to  claim 12 ,
 wherein a higher heating value (HHV) of the upgraded bio-oil is 30 to 40 MJ/kg according to Equation 4 below:   
       
         
           
             
               
                 
                   
                     
                       Higher 
                        
                       
                           
                       
                        
                       Heating 
                        
                       
                           
                       
                        
                       
                         Value 
                          
                         
                           ( 
                           
                             
                               H 
                                
                               
                                   
                               
                                
                               H 
                                
                               
                                   
                               
                                
                               V 
                             
                             , 
                             
                               MJ 
                               / 
                               Kg 
                             
                           
                           ) 
                         
                       
                     
                     = 
                     
                       
                         
                           34 
                            
                           C 
                         
                         + 
                         
                           124.3 
                            
                           H 
                         
                         + 
                         
                           6.3 
                            
                           N 
                         
                         + 
                         
                           19.3 
                            
                           S 
                         
                         - 
                         
                           9.8 
                            
                           O 
                         
                       
                       100 
                     
                   
                 
                 
                   
                     [ 
                     
                       Equation 
                        
                       
                           
                       
                        
                       4 
                     
                     ] 
                   
                 
               
             
           
         
         (In the Equation 4, each of C, H, N, S, and O represents mass ratios of carbon, hydrogen, nitrogen, sulfur, and oxygen, respectively, based on the total mass of all elements existing in the bio-oil). 
       
     
     
         15 . The upgraded bio-oil according to  claim 12 ,
 wherein the upgraded bio-oil has a moisture content of 0.5 to 6 weight %.   
     
     
         16 . The bio-oil according to  claim 12 ,
 wherein the Total Acid Number (TAN) according to ASTM D664 of the upgraded bio-oil, which is the amount of KOH needed to neutralize acids included in 1 g of bio-oil, is 1 to 35 mg, and pH of the upgraded bio-oil is 6 to 7.5.   
     
     
         17 . A fuel for power generation comprising the upgraded bio-oil of  claim 12 . 
     
     
         18 . A fuel for transportation comprising the upgraded bio-oil of  claim 12 .