Apparatus and process for treatment of fibers

Abstract

A process for treatment of fibers is disclosed. The treatment comprises simultaneously and continuously macerating the fibers and exposing the fibers to superheated steam, ammonia gas and ethylenediamine gas. The treatment is carried out in a chamber where the fibers are subjected to the mechanical rubbing and crushing action of a plurality of rotating pins against channels disposed on the chamber interior wall. The treatment results in improved fiber water holding capacity and improved conversion efficiency in the production of biofuels from the treated fibers.

1 . A process for treating fibers and fiber bundles containing a cellulose fraction, a lignin fraction and a hemicellulose fraction, said process comprising the steps of:
 softening the fibers;   swelling the fibers;   macerating the fibers; and   removing at least a portion of the lignin fraction and hemicellulose fraction from the fibers;   
     
     
         2 . The process of  claim 1  wherein the process steps are carried out substantially simultaneously. 
     
     
         3 . The process of  claim 1  wherein the process steps are carried out substantially continuously. 
     
     
         4 . The process of  claim 1 , wherein an apparatus for carrying out the process for treating fibers comprises:
 a chamber having a longitudinal central axis, a cylindrical enclosure, a feed zone and an exit zone, an interior portion having an interior surface and an exterior portion, said feed zone being adapted for communication with a fiber feeding device;   a shaft disposed along the longitudinal central axis of said chamber, said shaft being adopted for rotation around said axis;   a plurality of pins affixed to said central axis, said pins protruding from the central axis, said pins being substantially perpendicular in relation to the central axis; and   a plurality of channels disposed in an inner wall surface of the cylindrical enclosure, said each channel having a predetermined width, a predetermined depth and a predetermined clearance from the pins.   
     
     
         5 . The process of  claim 4 , wherein at least one of the pins has an upright shape. 
     
     
         6 . The process of  claim 4  wherein at least one of the pins has a helical shape. 
     
     
         7 . The process of  claim 4  wherein an upper portion of at least one pin comprises a triangular extension. 
     
     
         8 . The process of  claim 1  wherein removing at least a portion of the lignin fraction and hemicellulose fraction from the fibers comprises treating the fibers with a mixture of a gaseous amine and superheated steam in a gas phase. 
     
     
         9 . The process of  claim 1  wherein softening the fiber bundles comprises subjecting the fiber bundles to superheated steam. 
     
     
         10 . The process of  claim 1  wherein swelling the fibers comprises treating the fibers with a mixture of gaseous ammonia and superheated steam in a gas phase. 
     
     
         11 . The process of  claim 10 , wherein the gaseous ammonia is produced by heating anhydrous ammonia to an anhydrous ammonia boiling point. 
     
     
         12 . The process of  claim 10 , wherein the gaseous ammonia is produced by heating urea to a urea decomposition temperature. 
     
     
         13 . The process of  claim 8 , wherein the amine comprises ethylenediamine. 
     
     
         14 . The process of  claim 13 , wherein a gaseous ethylenediamine is produced by heating a water solution of ethylenediamine to a boiling point of said ethylenediamine, said heating resulting in a mixture of ethylenediamine gas and superheated steam. 
     
     
         15 . A process for treating fibers comprising:
 providing fibers and fiber bundles having a moisture level in the range of between about 2 percent and about 10 percent;   providing a treatment apparatus comprising a treatment chamber having a feed zone and an exit zone, said treatment chamber being adapted for pressurization;   feeding fibers and fiber bundles into the feed zone of a treatment apparatus and moving said fibers and fiber bundles from the feed zone toward the exit zone;   pre-treating the fibers and fiber bundles via a feed port disposed in the feed zone of the treatment chamber;   macerating the fibers and fiber bundles;   feeding a gaseous mixture containing steam, ammonia and ethylenediamine into the treatment chamber via at least one feed port disposed immediately downstream from the feed zone at a temperature of between about 140 degrees C. and about 180 degrees C. and a pressure of about 2 kilopascals gauge; and   collecting the fibers at the exit zone of said treatment apparatus, said fibers exiting from the treatment chamber having a moisture level in the range of between about 40 percent and about 60 percent.   
     
     
         16 . The process of  claim 15  wherein the treatment apparatus comprises:
 a chamber having a longitudinal central axis, a cylindrical enclosure, an interior portion having an interior surface and an exterior portion, said feed zone being adapted for communication with a fiber feeding device, said chamber being adapted for utilization under pressure; 
 a shaft disposed along the longitudinal central axis of said chamber, said shaft being adopted for rotation around said axis; 
 a plurality of pins affixed to said central axis, said pins protruding from the central axis, said pins being substantially perpendicular in relation to the central axis; and 
 a plurality of channels disposed in an inner wall surface of the cylindrical enclosure having a predetermined width, a predetermined depth and a predetermined clearance from the pins. 
 
     
     
         17 . The process of  claim 16 , wherein the clearance between the channels and an upper portion of the pins ranges from about 0.1 inches to about 0.3 inches. 
     
     
         18 . The process of  claim 16 , wherein the depth and the width of said groves range from about 0.2 inches to about 0.5 inches. 
     
     
         19 . The process of  claim 15 , wherein a method for producing the gaseous mixture containing steam, ammonia and ethylenediamine comprises heating an aqueous solution containing an ammonium base compound and ethylenediamine to a temperature between 140° C. and 180° C. 
     
     
         20 . The process of  claim 15 , further comprising washing the fibers collected at the exit of the treatment apparatus, and drying the fibers. 
     
     
         21 . The process of  claim 16 , wherein macerating the fibers comprises rotating the shaft at a speed of between 800 and 2000 revolutions per minute. 
     
     
         22 . The process of  claim 15 , further comprising defiberizing the fiber bundles prior to feeding the fiber bundles into the treatment chamber. 
     
     
         23 . The process of  claim 15 , wherein the gaseous mixture further comprises about 10% ethanol by volume. 
     
     
         24 . The process of  claim 19 , wherein the ammonium base compound is selected from the group consisting of urea and ammonium anhydride, and a feed rate of said ammonium base compound ranges from about 4 percent to about 30 percent by weight of the dry fibers. 
     
     
         25 . The process of  claim 19 , wherein a feed rate of the ethylenediamine ranges from about 2 percent to about 15 percent by weight of the dry fibers. 
     
     
         26 . The process of  claim 15  wherein pre-treating the fibers and fiber bundles comprises spraying droplets of an alkaline solution at an application rate ranging from about 0.01% to about 0.3% by weight of the oven dry fiber, wherein an alkaline component of the alkaline solution is selected from the group consisting of sodium hydroxide, calcium hydroxide and potassium hydroxide. 
     
     
         27 . The process of  claim 15  wherein pre-treating the fibers and fiber bundles comprises spraying droplets of an acid solution at an application rate ranging from about 0.01% to about 0.1% by weight of the oven dry fiber, said acid being selected from the group consisting of sulfuric acid, nitric acid and hydrochloric acid.