Enhancing biochar performance using pyrolysis acid stream

Abstract

A method of producing a modified biochar and the use of the biochar as a soil amendment. The modified biochar can be produced by contacting biochar with an acid-containing solution obtained from an acid containing stream produced in a pyrolysis process, which produces biochar. In accordance with one aspect, a cellulose-containing biomass is pyrolyzed to generate a gaseous organic acid-containing stream, which is condensed to produce an organic acid-containing solution. The biochar is then modified by contact with the organic acid-containing solution.

1 . A method of producing a modified biochar comprising:
 a) obtaining an acid-containing solution from a stream produced in a process for pyrolyzing biomass; and   b) contacting a biochar with at least a portion of the acid-containing solution to provide a modified biochar.   
     
     
         2 . The method of  claim 1 , wherein the acid-containing stream is produced from mild pyrolysis of the biomass at temperatures below 320° C. 
     
     
         3 . The method of  claim 2 , further comprising pyrolyzing the resulting mildly pyrolyzed biomass at higher temperatures to produce biochar. 
     
     
         4 . The method of  claim 3 , wherein the mild pyrolysis step occurs at a different location than the biochar producing pyrolysis. 
     
     
         5 . The method of  claim 1 , wherein the acid-containing stream is obtained from a biomass wash prior to pyrolysis. 
     
     
         6 . The method of  claim 5 , wherein the biomass washing occurs at a different location than the biochar producing pyrolysis process. 
     
     
         7 . The method of  claim 5 , wherein the biomass wash comprises an acid. 
     
     
         8 . The method of  claim 7 , wherein some or all of the acid is recycled from a step in the pyrolysis process. 
     
     
         9 . The method of  claim 7 , wherein some or all of the acid is recycled from a step in the biochar modification process. 
     
     
         10 . The method of  claim 5 , wherein the biomass wash comprises water. 
     
     
         11 . The method of  claim 10 , wherein some or all of the water is recycled from a step in the pyrolysis process. 
     
     
         12 . The method of  claim 10 , wherein some or all of the water is recycled from a step in the biochar enhancement process. 
     
     
         13 . The method of  claim 1 , wherein the acid-containing stream is produced from pyrolysis at temperatures between 300° C. and 600° C. 
     
     
         14 . The method of  claim 1 , wherein the acid-containing stream is produced from downstream processing of vapors evolved from biomass pyrolysis. 
     
     
         15 . The method of  claim 14 , wherein the acid-containing stream is separated from a water insoluble stream. 
     
     
         16 . The method of  claim 1 , wherein the biomass comprises a lignocellulosic material. 
     
     
         17 . The method of  claim 16 , wherein the lignocellulosic material comprises one or more of corn stover, corn cobs, empty fruit bunches, wood, wood residue, sawdust, sugar cane bagasse, switchgrass, sorghum, and agricultural crop wastes. 
     
     
         18 . The method of  claim 1 , wherein the acid-containing solution comprises an organic acid. 
     
     
         19 . The method of  claim 18 , wherein the organic acid-containing solution contains at least one acid selected from the group consisting of acetic acid, formic acid, propionic acid, glycolic acid, and other carboxylic acids. 
     
     
         20 . The method of  claim 1 , wherein the acid-containing solution comprises an inorganic acid. 
     
     
         21 .- 62 . (canceled)