Novel Off-Gas System for Coal and Biomass Pyrolysis

Abstract

The invention describes a unique and novel pyrolysis kiln for separating water vapor from a carbonaceous feedstock early in the pyrolysis process. The kiln structure includes two fans, one located near the proximal end of the kiln, the other near the kiln's distal end. Both fans create a local decrease in pressure at the respective ends with a dead zone in the intermediate region between the two ends of the kiln. At the proximal end, low temperature volatiles are removed, especially water vapor, and directed to a waste water cleanup station. Early removal of the water vapor makes the remaining pyrolysis process substantially more efficient. At the distal end, the high temperature hydrocarbons and other impurities are removed in a conventional manner and directed to a hot gas cleanup unit.

1 . A system for pyrolyzing carbonaceuous material to capture and isolate selected gases from said carbonaceous material, the pyrolyzing system comprising: a kiln, said kiln comprising an inner core and an outer shell, said shell and core each comprising a proximal and distal end and an inner and outer surface; a first airlock affixed to said proximal end of said inner core by means of a first rotating seal; a second airlock affixed to said distal end of said inner core by means of a second rotating seal; a first fan connected to tubulation emanating from said proximal end of said inner core; a second fan connected to tubulation emanating from said distal end of said inner core; a helical steel rail rigidly affixed along said inner surface of said inner core; heating coils fixedly attached to said inner surface of said kiln shell; a first condenser/separator connected to a water cleanup station positioned near the proximal end of said inner core; a second condenser/separator station, positioned near the distal end of said inner core, a first gear wheel surrounding said proximal circumferential end of said inner core; means for rotation of said core; a first tubulation connected between said first fan and first condense/separator unit; a second tubulation connected between said second fan and second condenser separator unit; a circular baffle and baffle stem, supporting mounts for elevating said system above ground level. 
     
     
         2 . A system as in  claim 1  wherein said inner core is mounted concentrically on slip rings within said outer shell, further comprising one or more thermal sensors positioned in the annular space between said concentrically mounted kiln shell and core. 
     
     
         3 . A system as in  claim 1  wherein first and second fans rotate further comprising the airflow produced by first and second fan to occur opposite directions. 
     
     
         4 . A system as in  claim 1  wherein said interior of said inner kiln core comprises at least one of a circular baffle and helical steel rail and any combination thereof. 
     
     
         5 . A system as in  claim 4  further comprising at least one steel baffle stem, with one end of said stem rigidly affixed to the periphery of said circular baffle, and with opposite end of said stem rigidly affixed to said helical steel rail, said steel rail affixed to inner surface of kiln core. 
     
     
         6 . A system as in  claim 4  and  5  with said baffle thickness in the range 0.25-5 inches, said baffle stem at least 4 inches in length, 2-4 inches in diameter, said baffle mounted from said proximal end of said core at a distance in the range 0.1 to 0.5 times the length of the said inner core. 
     
     
         7 . A system as in  claim 1  wherein said carbonaceous material external to said kiln is loaded into said inner core through said first airlock, said loading means further comprising a moving belt positioned between said first airlock and said external carbonaceous material. 
     
     
         8 . A system as in  claim 1  wherein said heating coils provide means for transferring heat to said carbonaceous material in said kiln core. 
     
     
         9 . A system as in  claim 1  wherein the carbonaceous material is selected from the group of materials consisting of coal, biomass and a combination of both. 
     
     
         10 . A system as in  claim 1  further comprising a motor and second gear, said second gear engaged with said first gear attached to the outer circumference of proximal end of said kiln core whereby said motor enables rotation of said kiln core by way of said second gear. 
     
     
         11 . A system as in  claim 1  and  10  wherein said rotation of said inner core comprises lateral movement of carbonaceous material from proximal to distal end of said inner core. 
     
     
         12 . A system as in  claim 1  wherein length of said kiln is in the range of 10 feet to 200 feet. 
     
     
         13 . A system as in  claim 1  wherein the diameter of said outer shell of said kiln is less than 18 feet but more than 1 foot. 
     
     
         14 . A system as in  claim 1  wherein the radius of said kiln core is at least 10% less than that of said shell of said kiln. 
     
     
         15 . A system as in  claim 1  wherein said heating coils are programmed to provide a temperature of approximately 100 C at the proximal end and approximately 500 C at the distal end of said kiln core. 
     
     
         16 . A system as in  claim 1  wherein heating of said carbonaceous material near the proximal end of said core gasifies said carbonaceous material, said gases drawn off by said first fan through said first tubulation and first rotating seal into said first condenser separator. 
     
     
         17 . A system as in  claim 1  wherein heating of said carbonaceous material near distal end of said core gasifies said carbonaceous material, said gases drawn off by said second fan through said tubulation and second rotating seal into second said condenser separator. 
     
     
         18 . A system as in  claim 16  and  17  wherein said gases are selected from the group of gases consisting of water vapor, hydrogen, hydrocarbons and any combination thereof. 
     
     
         19 . A control unit comprising means for controlling the temperature of a pyrolyzing system by way of signals transmitted to said unit from said thermal sensors mounted within said pyrolyzing system. 
     
     
         20 . A control unit as in  claim 19 , further comprising means for said unit to regulate the rotational speed of first and second fans mounted respectively at said proximal and distal end of said kiln core. 
     
     
         21 . A control unit as in  claim 19 , further comprising means for said unit to regulate the rotation speed of said core of said kiln core. 
     
     
         22 . A pyrolyzing system as in  claim 1  further comprising means for releasing solid carbonaceous material residing at the distal end of said kiln through said second airlock, further comprising a char receptacle to receive said carbonaceous material released through said second airlock.