Thermal fracture and microcarbon separation of coal particles

Abstract

A process for fracturing and devolatilizing coal particles rapidly exposes coal particles to a high temperature, oxygen-depleted work zone for a sufficient time period to cause volatile matter within the coal particles to vaporize and fracture the coal particles. The work zone has a temperature in the range from 600° C. to 2000° C. The coal particles are exposed to the high temperature, oxygen-depleted work zone for a time period less than 1 seconds, and preferably less than 0.3 second. The vaporized volatile matter is condensed and recovered as microcarbon particles.

1 . A process for fracturing coal particles comprising exposing coal particles to a high temperature, oxygen-depleted work zone for a time period less than 2 seconds to cause volatile matter within the coal particles to vaporize and fracture the coal particles and to produce coal-derived low volatile matter and fractured particles, wherein the work zone has a temperature in the range from 1000° C. to 2000° C., wherein the high temperature, oxygen-depleted work zone contains less than 1.5% oxygen. 
     
     
         2 . The process for fracturing coal particles according to  claim 1 , wherein the coal particles are exposed to the high temperature, oxygen-depleted work zone for a time period less than 1 second. 
     
     
         3 . The process for fracturing coal particles according to  claim 1 , wherein the coal particles are exposed to the high temperature, oxygen-depleted work zone for a time period less than 0.3 second. 
     
     
         4 . The process for fracturing coal particles according to  claim 1 , wherein the coal-derived low volatile matter and fractured particles have a diameter that is 5 times or more smaller than the original coal particles, a volatile matter content less than 10% by weight, a carbon content greater than 90% by weight, a sulfur content less than 1% by weight, a nitrogen content less than 1% by weight. 
     
     
         5 . The process for fracturing coal particles according to  claim 1 , wherein the coal particles have a particle size less than 10 mm. 
     
     
         6 . The process for fracturing coal particles according to  claim 1 , wherein the coal-derived low volatile matter and fractured particles have an average particle size less than 200 μm. 
     
     
         7 . The process for fracturing coal particles according to  claim 1 , wherein the vaporized volatile matter form coal-derived microcarbon particles within the work zone. 
     
     
         8 . The process for fracturing coal particles according to  claim 1 , wherein the high temperature, oxygen-depleted work zone is obtained from combustion gas exiting a pulse combustor or pulse jet engine. 
     
     
         9 . The process for fracturing coal particles according to  claim 1 , wherein the high temperature, oxygen-depleted work zone contains less than 1.0% oxygen. 
     
     
         10 . The process for fracturing coal particles according to  claim 1 , wherein the coal particles are unprocessed and have a given particle size, volatile matter content, sulfur content, and nitrogen content on an ash-free basis, and wherein the coal-derived low volatile matter and fractured particles are characterized by a reduction of two or more of particle size, volatile matter content, sulfur content, and nitrogen content on an ash-free basis compared to the unprocessed coal particles. 
     
     
         11 . A thermal mill for reducing the particle size of coal particles comprising:
 a work zone having a coal particle inlet and a fractured particle outlet;   a source of high temperature, oxygen-depleted gas connected to the work zone to provide the work zone with an operating temperature in the range from 1000° C. to 2000° C., wherein the high temperature, oxygen-depleted work zone contains less than 1.5% oxygen; and   a source of moving gas to entrain and convey coal particles via the coal particle inlet into the work zone for a time period less than 2 seconds to cause volatile matter within the coal particles to vaporize and fracture the coal particles, thereby forming coal-derived low volatile matter and fractured particles, and to entrain and convey the coal-derived low volatile matter and fractured particles via the fractured particle outlet.   
     
     
         12 . The thermal mill according to  claim 11 , further comprising a cyclone to recover the coal-derived low volatile and fractured particles. 
     
     
         13 . The thermal mill according to  claim 11 , wherein the coal particles have a particle size less than 10 mm. 
     
     
         14 . The thermal mill according to  claim 13 , wherein the coal-derived low volatile and fractured particles have an average particle size less than 200 μm. 
     
     
         15 . The thermal mill according to  claim 11 , wherein the coal particles are exposed to the work zone for a time period less than 1 second. 
     
     
         16 . A coal-derived solid material obtained by exposing unprocessed coal particles having a given particle size, volatile matter content, carbon content, sulfur content, nitrogen content, and entrained mineral matter content to an oxygen depleted gas at a temperature greater than 1000° C. for a time period less than 2 seconds, wherein the resulting coal-derived solid material is characterized by a reduction of one or more of particle size, volatile matter content, carbon content, sulfur content, nitrogen content, and entrained mineral matter content compared to the unprocessed coal particles. 
     
     
         17 . The coal-derived solid material according to  claim 16 , having a sulfur content less than 50% of the sulfur content of the unprocessed coal particles. 
     
     
         18 . The coal-derived solid material according to  claim 16 , having a volatile matter content less than 10% by weight. 
     
     
         19 . The coal-derived solid material according to  claim 16 , having an average particle size less than 50% of the average particle size of the unprocessed coal particles. 
     
     
         20 . The coal-derived solid material according to  claim 16 , having a reduced diameter compared to the unprocessed coal particles, a volatile matter content less than 10% by weight, a carbon content greater than 90% by weight, a sulfur content less than 1% by weight, and a nitrogen content less than 1.5% by weight. 
     
     
         21 . The coal-derived solid material according to  claim 16 , consisting of coal-derived low volatile matter and fractured particles. 
     
     
         22 . The coal-derived solid material according to  claim 16 , consisting of coal-derived microcarbon particles.