High-Yield Pitch Synthesis Process for Producing Carbon Fiber Using Low-Severity Direct Coal Liquefaction
Systems and methods of processing coal to form mesophase pitch include performing a low-severity direct coal liquefaction (LSDCL) process on a coal feedstock to produce a coal tar pitch therefrom. The systems and methods can include contacting coal directly with a catalyst in the presence of a solvent, pressurizing the coal in direct contact with the catalyst in the presence of the solvent to a predetermined pressure of about 1000 psia or less, heating the coal in direct contact with the catalyst in the presence of the solvent to a predetermined temperature of about 380° C. or less, and liquefying the coal to form a coal tar pitch. The coal tar pitch can be thermally treated to a liquid crystal phase exhibiting anisotropic spheres of mesophase and spun to form carbon fibers.
1 . A coal processing system, comprising:
an auto-clave apparatus configured to assess the reactivity of an amount of coal and to form a filter cake of ash and insoluble organic matter from a filter wash material of the auto-clave apparatus;
a direct liquefaction reactor comprising a chamber configured to directly contact an amount of coal with a catalyst in the presence of a solvent and hydrogen gas, wherein the hydrogen gas is provided by gasifying coal, biomass, or a liquefaction residue; and
a controller coupled to the direct liquefaction reactor and configured to cause the direct liquefaction reactor to:
pressurize the chamber to a predetermined pressure between about 500 pounds per square inch absolute (psia) and about 1000 psia;
heat the chamber to a predetermined temperature of about 380° C. or less; and
liquefy at least some of the amount of coal present in the chamber to form a coal tar pitch, wherein the hydrogen gas is added to exert the predetermined pressure and break down the amount of coal into soluble products.
2 . The system of claim 1 , wherein the predetermined pressure is about 950 psia.
3 . The system of claim 1 , wherein the predetermined pressure is one of about 850, about 750, about 650, about 550, or about 450.
4 . The system of claims 1 , wherein the predetermined temperature is one of about 375° C., 370° C., 365° C., 360° C., 355° C., 350° C. or less.
5 . The system of claim 1 , wherein the controller is further configured to cause the direct liquefaction reactor to thermally treat the coal tar pitch to a liquid crystal phase exhibiting anisotropic spheres of a mesophase pitch.
6 . The system of claim 1 , wherein the controller is further configured spin the mesophase pitch to form carbon fibers.
7 . A controller for operating a direct liquefaction reactor, the controller comprising:
a processor; and
a memory coupled to the processor and containing computer-executable instructions that, when executed by the processor, cause the controller to:
screen an amount of coal for coal reactivity characterization
operate the direct liquefaction reactor to pressurize a chamber containing an amount of coal in direct contact with a catalyst in the presence of a solvent and hydrogen gas to a predetermined pressure between about 500 pounds per square inch absolute (psia) and about 1000 psia or less, wherein the hydrogen gas is provided by gasifying coal, biomass, or a liquefaction residue;
operate the direct liquefaction reactor to heat the chamber containing the amount of coal in direct contact with the catalyst in the presence of the solvent to a predetermined temperature of about 380° C. or less; and
operate the direct liquefaction reactor to liquefy at least some of the amount of coal to form a coal tar pitch, wherein the hydrogen gas is added to exert the predetermined pressure and break down the amount of coal into soluble products.
8 . The controller of claim 7 , wherein the predetermined pressure is about 900 psia.
9 . The controller of claim 7 , wherein the predetermined pressure is one of about 800 psia.
10 . The controller of claim 7 , wherein the predetermined temperature is about 365° C. or less.
11 . The controller of claim 7 , wherein the predetermined temperature is about 355° C. or less.