Recyclable buffer for the hydrothermal hydrocatalytic treatment of biomass

Abstract

A method of hydrothermal hydrocatalytic treating biomass is provided. Lignocellulosic biomass solids is provided to a hydrothermal digestion unit in the presence of a digestive solvent, at least one of ammonia or a source of ammonia, and a supported hydrogenolysis catalyst containing (a) sulfur, (b) Mo or W, and (c) Co, Ni or mixture thereof, incorporated into a suitable support. The lignocellulosic biomass solids and digestive solvent are heated in the presence of hydrogen, supported hydrogenolysis catalyst and the at least one of ammonia or a source of ammonia forming a product solution containing plurality of oxygenated hydrocarbons and ammonia. At least a portion of ammonia is separated and recycled to the hydrothermal digestion unit.

We claim: 
     
         1 . A method comprising: (i) providing lignocellulosic biomass solids in a hydrothermal digestion unit in the presence of a digestive solvent, at least one of ammonia or a source of ammonia, and a supported hydrogenolysis catalyst containing (a) sulfur, (b) Mo or W, and (c) Co, Ni or mixture thereof, incorporated into a suitable support; (ii) heating the lignocellulosic biomass solids and digestive solvent in the presence of hydrogen, supported hydrogenolysis catalyst and the at least one of ammonia or a source of ammonia thereby forming a product solution containing plurality of oxygenated hydrocarbons and ammonia; and (iii) recycling at least a portion of the ammonia to the hydrothermal digestion unit. 
     
     
         2 . The method of  claim 1  where the source of ammonia is selected from the group consisting of: ammonium carbonate, ammonium propionate, ammonium glycolate, ammonium levulinate, ammonium acetate, ammonium formate, ammonium butyrate, ammonium chloride, and ammonium sulfate. 
     
     
         3 . The method of  claim 1  wherein the source of ammonia is an ammonium salt. 
     
     
         4 . The method of  claim 1  wherein ammonia is provided to the reaction mixture. 
     
     
         5 . The method of  claim 4  wherein ammonia is generated external to the reaction mixture. 
     
     
         6 . The method of  claim 1  wherein the source of ammonia is provided by addition of strong base to an ammonium salt of a strong acid. 
     
     
         7 . The method of  claim 6  wherein the strong base is KOH or NaOH and the ammonium salt is ammonium sulfate. 
     
     
         8 . The method of  claim 1  wherein a first portion of the oxygenated hydrocarbons are recycled to form in part the digestive solvent. 
     
     
         9 . A method comprising: (i) providing a lignocellulosic biomass; (ii) contacting the biomass with a digestive solvent to form a pretreated biomass containing soluble carbohydrates; (iii) contacting, in a reaction mixture, the pretreated biomass with hydrogen at a temperature in the range of 150° C. to less than 300° C. in the presence of at least one of ammonia or a source of ammonia and a supported hydrogenolysis catalyst containing (a) sulfur, (b) Mo or W, and (c) Co, Ni or mixture thereof, incorporated into a suitable support, to form a product solution containing plurality of oxygenated hydrocarbons and ammonia; and (iv) recycling at least a portion of the ammonia to the reaction mixture or to the pretreated biomass. 
     
     
         10 . The method of  claim 9  where the source of ammonia is selected from the group consisting of: ammonium carbonate, ammonium propionate, ammonium glycolate, ammonium levulinate, ammonium acetate, ammonium formate, ammonium butyrate, ammonium chloride, and ammonium sulfate. 
     
     
         11 . The method of  claim 9  wherein the source of ammonia is an ammonium salt. 
     
     
         12 . The method of  claim 9  wherein ammonia is provided to the reaction mixture. 
     
     
         13 . The method of  claim 12  wherein ammonia is generated external to the reaction mixture. 
     
     
         14 . The method of  claim 9  wherein the source of ammonia is provided by addition of strong base to an ammonium salt of a strong acid. 
     
     
         15 . The method of  claim 14  wherein the strong base is KOH or NaOH and the ammonium salt is ammonium sulfate. 
     
     
         16 . The method of  claim 9  wherein a first portion of the oxygenated hydrocarbons are recycled to form in part the solvent in step (ii). 
     
     
         17 . The method of  claim 9  wherein ammonia is recycled with the first portion of the oxygenated hydrocarbons. 
     
     
         18 . The method of  claim 9  wherein the ammonia is recycled separately as an ammonia stream to the reaction mixture or pretreated biomass. 
     
     
         19 . The method of  claim 1  wherein sulfur content of the catalyst is in the range of 0.1 wt % to 40 wt % based on components (b) and (c) as metal oxide form. 
     
     
         20 . The method of  claim 19  wherein the Co and/or Ni content of the catalyst is in the range of about 0.5 wt. % to about 20 wt. % based on components (b) and (c) as metal oxide form. 
     
     
         21 . The method of  claim 9  wherein sulfur content of the catalyst is in the range of 0.1 wt % to 40 wt % based on components (b) and (c) as metal oxide form. 
     
     
         22 . The method of  claim 21  wherein the Co and/or Ni content of the catalyst is in the range of about 0.5 wt. % to about 20 wt. % based on components (b) and (c) as metal oxide form. 
     
     
         23 . A composition comprising:
 (i) lignocellulosic biomass;   (ii) hydrogenolysis catalyst containing (a) sulfur, (b) Mo or W, and (c) Co, Ni or mixture thereof, incorporated into a suitable support;   (iii) water; and   (iv) at least one of ammonia or a source of ammonia.   
     
     
         24 . The composition of  claim 23  wherein the composition further comprises (v) digestive organic solvent. 
     
     
         25 . The composition of  claim 23 , wherein component (iv) is selected from the group consisting of ammonia, ammonium carbonate, ammonium propionate, ammonium glycolate, ammonium levulinate, ammonium acetate, ammonium formate, ammonium butyrate, ammonium chloride, and ammonium sulfate. 
     
     
         26 . The composition of  claim 23 , wherein the catalyst further comprises (d) phosphorus.