Methods of drying biomass and carbonaceous materials

Abstract

The invention provides methods of reducing the energy required to remove moisture from biomass, carbonaceous materials and mixtures of the same. The method significantly reduces the energy requirements by removing moisture as a liquid and by transferring the moisture to the surface of the material where it is more easily and efficiently evaporated.

1 . A method of reducing the energy consumed by drying biomass and carbonaceous materials comprising:
 a. preparing feedstock to expose its moisture-containing structure,   b. compacting the prepared material to form a compacted material, and,   c. separating water expressed during compaction from the compacted material to form a dried compacted material.   
     
     
         2 . The method of  claim 1 , wherein the feedstock is selected from the group consisting of woody material, grasses, agricultural plants, residues, bituminous coal, subbituminous coal, lignite, brown coal, peat, and waste coal materials produced by screening or gravity separation processes, and combinations thereof. 
     
     
         3 . (canceled) 
     
     
         4 . The method of  claim 1  wherein the preparing comprises the use of a device that reduces the size of the feed material to maximize the exposure of porous structure(s) of the material that contains surface or inherent or bonded water to an exterior surface. 
     
     
         5 . The method of  claim 1 , wherein the compacting comprises the use of a device that develops sufficient pressure to deform the integrity of the material structure to release water contained therein. 
     
     
         6 . The method of  claim 5 , wherein the device is a double roll press. 
     
     
         7 . (canceled) 
     
     
         8 . The method of  claim 1 , wherein the separating comprises at least one of
 use of a vibrating screening machine to separate liquid water as underflow from dewatered compacted material as overflow;   use of a belt filter press to separate liquid water as filtrate from dewatered compacted material as filter cake;   centrifuging the compacted material to separate liquid water as effluent from dewatered compacted material as product;   vacuuming the compacted material through a disk filter to separate liquid water as filtrate from dewatered compacted material as filter cake;   evaporating water from an exterior surface of the compacted material; and,   thermally drying the compacted material at low temperature.   
     
     
         9 - 11 . (canceled) 
     
     
         12 . The method of  claim 1 , wherein the feedstock comprises a mixture of biomass and carbonaceous material. 
     
     
         13 . (canceled) 
     
     
         14 . The method of  claim 12 , wherein the biomass and the carbonaceous materials are prepared separately. 
     
     
         15 . The method of  claim 12 , wherein the biomass and the carbonaceous materials are compacted and separated from liquid water separately. 
     
     
         16 . The method of  claim 12 , wherein the biomass and the carbonaceous materials are compacted and separated as a mixture. 
     
     
         17 . (canceled) 
     
     
         18 . The method of  claim 1 , further comprising thermally drying the dried compacted material at low temperature to form a low moisture compacted material. 
     
     
         19 . The method of  claim 1 , further comprising briquetting the low moisture compacted material. 
     
     
         20 . A biomass compacted material having a moisture content between about 5 wt % and about 17 wt. %. 
     
     
         21 - 50 . (canceled) 
     
     
         51 . A method of forming a briquette comprising biomass and a carbonaceous material, the method comprising:
 a. sizing a first feed stream comprising biomass into a size that maximizes exposure of the porous structure of the biomass;   b. compacting the sized first feed stream in a roll press to rupture and collapse the first feed's porous structure and to express moisture held within the pores of the first feed stream material;   c. separating water expressed during compaction of the first feed stream to form a dried biomass;   d. comminuting a second feed stream comprising mined or reclaimed carbonaceous materials;   e. compacting the second feed stream in a roll press;   f. separating water expressed during compaction of the second feed stream to form a dried carbonaceous material;   g. combining the dried biomass and the dried carbonaceous material to form a combined material stream; and   h. briquetting the combined material stream to form a briquette comprising processed and dried biomass and carbonaceous materials.   
     
     
         52 . The method of  claim 14 , wherein pressure applied in compacting the first feed stream is between 5,000 lb/in 2  and 80,000 lb/in 2 .