Molten salt pyrolysis for bio-oil and chemicals

Abstract

A bio-oil reactor leverages chemically recalcitrant lignocellulosic biomass using a moderate temperature molten-salt based process to unlock hydrocarbon content having the potential to substantially supplement demand for petroleum based fuels and chemicals. Bio-oil is a precursor to production of other chemicals and hydrocarbons, and can be refined as an effective replacement to conventional petroleum products and fossil fuels. A disclosed approach employs Molten-Salt Pyrolysis (MSP), for the efficient and economical production of such precursor chemicals directly from whole biomass under moderate conditions (˜400° C., 1 atm.). Lignocellulosic biomass, freely available in renewable wood and plant products, undergoes a moderate temperature heating process in a eutectic molten salt mixture to generate a condensable vapor of the precursor or platform chemicals.

What is claimed is: 
     
         1 . A method of producing bio-oil and chemicals from biomass, comprising:
 combining a plurality of salts to form a eutectic salt mixture having a melting point lower than any of the salts individually;   adding a particulated biomass to form a mixture with the eutectic salt;   heating the mixture in a containment sealed from ambient oxygen to a temperature above the melting point to generate a molten salt mixture including the particulated biomass and resulting in a product vapor;   collecting the product vapor, the vapor including bio-oil components and chemicals, and   condensing the vapor for recovering the bio-oil components to generate bio-oil for refining.   
     
     
         2 . The method of  claim 1  wherein the bio-oil is defined by a plurality of organic compounds resulting from a solution and deconstruction of the lignocellulose biomass. 
     
     
         3 . The method of  claim 2  wherein the biomass is a lignocellulosic biomass defined by a matrix of cross-linked polysaccharide network of cellulose (C 6  sugars) a hemicellulose (C 5  sugars) and lignin. 
     
     
         4 . The method of  claim 1  wherein the vapor further includes non-volatile components resulting from heating below a temperature defining conventional pyrolysis. 
     
     
         5 . The method of  claim 1  wherein a liquid yield of bio-oil is between 40-60% of the added biomass. 
     
     
         6 . The method of  claim 5  wherein the temperature is below 450° C. 
     
     
         7 . The method of  claim 6  wherein the temperature is between 300-400° C. 
     
     
         8 . The method of  claim 1  further comprising recovering and reusing the molten salt, the molten salt being unconsumed by any evaporative process. 
     
     
         9 . The method of  claim 1  further comprising introducing an inert gas into the sealed containment for displacing the vapor to a lower temperature containment for condensing and to ensure an inert atmosphere. 
     
     
         10 . The method of  claim 1  wherein vaporization of the bio-mass occurs at a temperature between low-temperature conventional solvent based processes and high temperature pyrolysis, the high temperature pyrolysis defined by gasification of non-condensable gases including H 2  and CO 2 . 
     
     
         11 . The method of  claim 5  further resulting in condensing furfural in a purity of at least 75% and a yield of at least 21%. 
     
     
         12 . The method of  claim 5  further resulting in condensing acetic acid in a purity of at least 75% and a yield of at least 25% at a temperature substantially around 105° C. 
     
     
         13 . The method of  claim 5  further resulting in a mixture of organic chemicals comprising the bio-oil. 
     
     
         14 . The method of  claim 1  wherein the plurality of salts are selected from the group consisting of:
   ZnCl 2 —KCl—LiCl,
 
   AlCl 3 —KCl,
 
   AlCl 3 —NaCl,
 
   CuCl—KCl,
 
   ZnCl 2 —KCl—NaCl,
 
   ZnCl 2 —KCl—NaCl,
 
   KCl—LiCl—NaCl,
 
   KCl—LiCl—NaCl,
 
   KCl—MgCl 2 —NaCl,
 
   ZnCl 2 , 
   ZnCl 2 —KCl,
 
   ZnCl 2 —NaCl and
 
   ZnCl 2 —SnCl 2 .
 
 
     
     
         15 . The method of  claim 1  wherein the bio-oil yield contains compounds selected from the group consisting of:
 Acetic acid, 
 Furfural, 
 2-propanone,1-hydroxy-, 
 Acetic acid, methyl ester, 
 Propanic acid, 
 1-hydroxy-2-butanone, 
 2-cyclopenten-1-one,2-hydroxy-, 
 Phenol,2-methoxy-4-methyl and 
 Ethanone,1-(2-furanyl)-. 
 
     
     
         16 . A biomass reactor device, comprising:
 a containment vessel sealed from ambient oxygen and having a plurality of combined salts to form a eutectic salt mixture having a melting point lower than any of the salts individually;   a feeder to add a particulated biomass to form a mixture with the eutectic salt;   a heat source to heat the mixture in the containment to an operating temperature above the melting point of the eutectic salt mixture to generate a molten salt mixture including the particulated biomass and resulting in a vapor;   an outflow from the containment vessel to collect the vapor, the vapor including bio-oil components, and   at least one condenser coupled to the outflow to receive and condense the vapor and recover the bio-oil components to generate bio-oil for refining.   
     
     
         17 . The device of  claim 16  wherein the bio-oil is defined by organic compounds resulting from a lignocellulose solution and deconstruction of the biomass, and the biomass is a lignocellulosic biomass defined by a matrix of cross-linked polysaccharide network of cellulose (C 6  sugars) a hemicellulose (C 5  sugars) and lignin. 
     
     
         18 . The device of  claim 16  wherein the vapor includes non-volatile components resulting from heating below a temperature defining pyrolysis, the vaporization of the bio-mass occurring at a temperature between low temperature conventional solvent based processes and high temperature pyrolysis that would result in substantial gasification of non-condensable gases including H 2  and CO 2 . 
     
     
         19 . The device of  claim 16  wherein the liquid yield of bio-oil is between 40-60% of the added biomass and the operating temperature is between 300-450° C. 
     
     
         20 . The device of  claim 16  wherein the reactor is operative to recover and reusing the molten salt, the molten salt being unconsumed by the evaporative process, and further operative to introduce an inert gas into the sealed containment for displacing the vapor to a lower temperature containment for condensing and to ensure an inert atmosphere. 
     
     
         21 . The device of  claim 16  further comprising:
 a condensed bio-oil containing furfural in a purity of at least 75% and a yield of at least 21% at a temperature substantially around 120° C., and 
 a condensed bio-oil containing acetic acid in a purity of at least 75% and a yield of at least 25% at a temperature substantially around 105° C.