Thermal fracture and microcarbon separation of coal particles
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 and devolatilizing 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 exit the coal particles, to fracture the coal particles and produce coal-derived low volatile matter and fractured particles, and to produce coal-derived microcarbon 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 and devolatilizing 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 one or more of particle size, volatile matter content, sulfur content, and nitrogen content on an ash-free basis compared to the unprocessed coal particles.
3. The process for fracturing and devolatilizing coal particles according to claim 1 , wherein the coal particles are unprocessed and have a given carbon content on an ash-free basis, and wherein the coal-derived low volatile matter and fractured particles are characterized by an increase in carbon content on an ash-free basis compared to the unprocessed coal particles.
4. The process for fracturing and devolatilizing coal particles according to claim 1 , wherein the coal-derived low volatile matter and fractured particles have a sulfur content less than 50% of the sulfur content of the unprocessed coal particles on an ash-free basis.
5. The process for fracturing and devolatilizing coal particles according to claim 1 , wherein the coal-derived low volatile matter and fractured particles have a volatile matter content less than 10% by weight.
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 50% of the average particle size of the unprocessed coal particles.
7. The process for fracturing and devolatilizing coal particles according to claim 1 , wherein the coal-derived low volatile matter and fractured particles have 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 on an ash-free basis, a sulfur content less than 1% by weight on an ash-free basis, and a nitrogen content less than 1.5% by weight on an ash-free basis.
8. The process for fracturing and devolatilizing 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 and devolatilizing coal particles according to claim 1 , wherein the coal-derived microcarbon particles have a diameter less than 1 mm, 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, and an ash content less than 1% by weight.
10. The process for fracturing and devolatilizing coal particles according to claim 9 , wherein the coal-derived microcarbon particles are electrically conductive.
11. The process for fracturing and devolatilizing 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 seconds.
12. The process for fracturing and devolatilizing coal particles according to claim 1 , wherein the coal particles have a particle size less than 10 mm.
13. The process for fracturing and devolatilizing coal particles according to claim 1 , wherein the high temperature, oxygen-depleted work zone contains less than 1.0% oxygen.
14. The process for fracturing and devolatilizing coal particles according to claim 1 , wherein the high temperature, oxygen-depleted work zone contains less than 0.5% oxygen.