Method of Producing Synthetic Pitch

Abstract

Embodiments of a method are described for modifying pitches, oils, tars, and binders by using these materials as solvents to extract organic chemicals from coal.

1 . A method of producing a synthetic binder pitch from coal, comprising:
 (a) hydrogenating feedstock solvent in a first tank reactor, wherein the feedstock solvent comprises at least one additional solvent selected from the group consisting of: tetralin, decalin, tetrahydrofuran, and aprotic dipolar solvents such as n-methyl pyrrolidone;   (b) producing a mixture of hydrogenated and unhydrogenated feedstock solvents by combining said hydrogenated feedstock solvent exiting said first tank reactor with unhydrogenated feedstock solvent;   (c) combining said mixture of hydrogenated and unhydrogenated feedstock solvents with coal to produce an extraction mixture in a second tank reactor downstream of said first reactor;   (d) heating said extraction mixture for a period of time sufficient to extract one or more soluble portions of said coal into said mixture of hydrogenated and unhydrogenated feedstock solvents;   (e) removing undissolved solids from said extraction mixture;   (f) removing light hydrocarbons from said extraction mixture, thereby producing a the synthetic binder pitch, wherein the synthetic binder pitch comprises a softening temperature between 100 and 120° C. and a coking value between 50 and 60% by weight; and   (g) recycling said light hydrocarbons and at least a portion of said mixture of hydrogenated and unhydrogenated feedstock solvents to said second tank reactor.   
     
     
         2 . The method of  claim 1 , wherein between about 10% and about 15% by weight of said pitch comprises species provided by said at least one feedstock solvent 
     
     
         3 - 4 . (canceled) 
     
     
         5 . The method of  claim 1 , wherein said at least one feedstock solvent is selected from the group consisting of coal tar distillates, petroleum distillates, petroleum catalytic cracker products, distillates of gasification tars, products from the pyrolysis of recycled hydrocarbons, and aromatic oil products obtained from the distillation of shale oil or tar sands. 
     
     
         6 . The method of  claim 1 , wherein said hydrogenating step comprises heating at least a portion of the feedstock solvent to a temperature of between about 200° C. and about 500° C. in a hydrogen atmosphere with a hydrogen pressure of up to about 3000 psig, such that the feedstock solvent of the extraction mixture has between about 0.1% and about 10% absorbed hydrogen by weight. 
     
     
         7 . (canceled) 
     
     
         8 . The method of  claim 1 , wherein at least 10% of said feedstock solvent comprises one or more of coal tar distillates, petroleum distillates, or distillates of gasification tars. 
     
     
         9 - 16 . (canceled) 
     
     
         17 . The method of  claim 1 , further comprising the step of air blowing said extraction mixture at a temperature of between about 70° C. and about 500° C. after said step of removing at least a portion of said light hydrocarbons. 
     
     
         18 . The method of  claim 1 , further comprising the step of agitating said extraction mixture during heating, wherein said agitating step is performed by at least one of mechanical stirring and applying ultrasound. 
     
     
         19 . The method of  claim 1 , further comprising the step of agitating said feedstock solvent in the presence of hydrogen, in order to enhance absorption of hydrogen, wherein such agitating step is performed by at least one of mechanical stirring and applying ultrasound. 
     
     
         20 . The method of  claim 1 , wherein said coal is selected from the group consisting of bituminous coals, sub-bituminous coals, and lignite coals. 
     
     
         21 . The method of  claim 1 , wherein at least 85% of said coal is extracted by said mixture of hydrogenated and unhydrogenated feedstock solvents. 
     
     
         22 . A method of producing a synthetic binder pitch from coal, comprising:
 (a) hydrogenating feedstock solvent in a first tank reactor, wherein the feedstock solvent comprises at least one additional solvent selected from the group consisting of: tetralin, decalin, tetrahydrofuran, and aprotic dipolar solvents such as n-methyl pyrrolidone;   (b) producing a mixture of hydrogenated and unhydrogenated feedstock solvents by combining said hydrogenated feedstock solvent exiting said first tank reactor with unhydrogenated feedstock solvent;   (c) combining said mixture of hydrogenated and unhydrogenated feedstock solvents with coal to produce an extraction mixture in a second tank reactor downstream of said first reactor, wherein said coal is selected from the group consisting of bituminous coals, sub-bituminous coals, and lignite coals;   (d) heating said extraction mixture for a period of time sufficient to extract one or more soluble portions of said coal into said mixture of hydrogenated and unhydrogenated feedstock solvents, wherein at least 85% of said coal is extracted into said mixture of hydrogenated and unhydrogenated feedstock solvents;   (e) removing undissolved solids from said extraction mixture by centrifugation;   (f) removing light hydrocarbons from said extraction mixture in a fractional distillation unit, thereby producing the synthetic binder pitch, wherein the synthetic binder pitch comprises a softening temperature between 100 and 120° C. and a coking value between 50 and 60% by weight; and   (g) recycling said light hydrocarbons and at least a portion of said mixture of hydrogenated and unhydrogenated feedstock solvents to said second tank reactor.