Process for removing a contaminant from coal tar

Abstract

A process for removing at least one contaminant from coal tar is described. The process involves extraction with an extraction agent or adsorption with an adsorbent. The extraction agent includes at least one of amphiphilic block copolymers, inclusion complexes of poly(methyl methacrylate) and polycyclic aromatic hydrocarbons, cyclodextrins, functionalized cyclodextrins, and cyclodextrin-functionalized polymers, and the adsorbent includes exfoliated graphite oxide, thermally exfoliated graphite oxide or intercalated graphite compounds.

What is claimed is: 
     
         1 . A process for removing at least one contaminant from coal tar comprising:
 providing at least a portion of a coal tar stream;   removing at least one contaminant from the at least the portion of the coal tar stream by extraction with an extraction agent or adsorption with an adsorbent to form a treated coal tar stream having a reduced level of the at least one contaminant, the extraction agent comprising at least one of amphiphilic block copolymers, inclusion complexes of poly(methyl methacrylate) and polycyclic aromatic hydrocarbons, cyclodextrins, functionalized cyclodextrins, and cyclodextrin-functionalized polymers, the adsorbent comprising exfoliated graphite oxide, thermally exfoliated graphite oxide or intercalated graphite compounds, and the at least one contaminant comprising nitrogen heterocyclic aromatics, oxygen heterocyclic aromatics, and sulfur heterocyclic aromatics;   separating the at least the portion of the coal tar stream into at least two fractions.   
     
     
         2 . The process of  claim 1  wherein the extraction agent comprises the amphiphilic block copolymer, and wherein the amphiphilic block copolymer comprises at least two blocks selected from polyethylene oxide blocks, polypropylene oxide blocks, butylene oxide blocks, silicone blocks, urethane blocks, polyurethane ionomer blocks, acrylate ionomer blocks, polymethylacryate blocks, polyacrylic acid blocks, and polyvinylidene chloride blocks. 
     
     
         3 . The process of  claim 1  wherein the extraction agent further comprises an ionic liquid, or a supercritical fluid, or both. 
     
     
         4 . The process of  claim 3  wherein the extraction agent further comprises the ionic liquid, and wherein the ionic liquid is selected from imidazolium-based ionic liquid, pyrrolidinium-based ionic liquid, pyridinium-based ionic liquid, sulphonium-based ionic liquids, phosphonium-based ionic liquids, and ammonium-based ionic liquids. 
     
     
         5 . The process of  claim 3  wherein the extraction agent further comprises the supercritical fluid, and wherein the supercritical fluid comprises supercritical carbon dioxide, supercritical ammonia, supercritical ethane, supercritical propane, supercritical butane, or supercritical water. 
     
     
         6 . The process of  claim 5  wherein the supercritical fluid is the supercritical ammonia, wherein one of the separated fractions comprises ammonia, and wherein the ammonia in the fraction is processed into the supercritical ammonia. 
     
     
         7 . The process of  claim 5  wherein the supercritical fluid is the supercritical carbon dioxide, wherein one of the separated fractions comprises carbon dioxide, and wherein the carbon dioxide in the fraction is processed into the supercritical carbon dioxide. 
     
     
         8 . The process of  claim 1  wherein at least two contaminants are removed, and wherein the first contaminant is removed using a first extraction agent or adsorbent and wherein the second contaminant is removed using a second extraction agent or adsorbent after the removal of the first contaminant and before separating the at least the portion of the coal tar stream into the at least two fractions. 
     
     
         9 . The process of  claim 1  further comprising removing at least one additional contaminant by adsorption with a second adsorbent, or an oxidation reaction, the at least one additional contaminant comprising arsenic, metal compounds, mercury halides, elemental mercury, inorganic halides, organic halides, and coal tar insolubles, and wherein the second adsorbent comprises a noble metal deposited on a support selected from the group consisting of molecular sieves, alumina, activated carbons, and silica gel; silver impregnated zeolite selected from the group consisting of faujasites (13X, CaX, NaY, CaY, and ZnX), chabazites, clinoptilolites and LTA (3A, 4A, 5A) zeolites; sulfur or a metal sulfide on an activated carbon support or an activated alumina support; or a metal sulfide, metal oxide, or metal carbonate on a support, the metal is selected from the group consisting of copper, silver, gold, antimony, lead, and manganese, and the support selected from the group consisting of activated alumina, clay, or activated carbon. 
     
     
         10 . The process of  claim 1  further comprising reducing a viscosity of the at least the portion of the coal tar stream before removing the at least one contaminant. 
     
     
         11 . The process of  claim 10  wherein the viscosity is reduced by mixing the at least the portion of the coal tar fraction with a solvent. 
     
     
         12 . The process of  claim 1  further comprising processing at least one of the fractions to produce at least one product. 
     
     
         13 . The process of  claim 12  wherein the at least one fraction is processed by at least one of hydrotreating, hydrocracking, fluid catalytic cracking, alkylation, transalkylation, oxidation, or hydrogenation. 
     
     
         14 . The process of  claim 1  wherein the at least one contaminant is removed before the at least the portion of the coal tar stream is separated into the at least two fractions. 
     
     
         15 . The process of  claim 1  wherein the at least one contaminant is removed after the at least the portion of the coal tar stream is separated into the at least two fractions. 
     
     
         16 . A process for removing at least one contaminant from coal tar comprising:
 pyrolyzing a coal feed into a coal tar stream and a coke stream;   removing at least one contaminant from at least a portion of the coal tar stream by extraction with an extraction agent or adsorption with an adsorbent to form a treated coal tar stream having a reduced level of the at least one contaminant, the extraction agent comprising at least one of amphiphilic block copolymers, inclusion complexes of poly(methyl methacrylate) and polycyclic aromatic hydrocarbons, cyclodextrins, functionalized cyclodextrins, and cyclodextrin-functionalized polymers, the adsorbent comprising exfoliated graphite oxide, thermally exfoliated graphite oxide or intercalated graphite compounds, and the at least one contaminant comprising nitrogen heterocyclic aromatics, oxygen heterocyclic aromatics, and sulfur heterocyclic aromatics:   separating the coal tar portion into at least two fractions: and processing at least one of the fractions to produce at least one product.   
     
     
         17 . The process of  claim 16  wherein the extraction agent comprises the amphiphilic block copolymer, and wherein the amphiphilic block copolymer comprises at least two blocks selected from polyethylene oxide blocks, polypropylene oxide blocks, butylene oxide blocks, silicone blocks, urethane blocks, polyurethane ionomer blocks, acrylate ionomer blocks, polymethylacryate blocks, polyacrylic acid blocks, and polyvinylidene chloride blocks. 
     
     
         18 . The process of  claim 16  wherein the extraction agent further comprises an ionic liquid, or a supercritical fluid, or both. 
     
     
         19 . The process of  claim 16  further comprising reducing a viscosity of the coal tar fraction before removing the at least one contaminant. 
     
     
         20 . The process of  claim 16  wherein the at least one fraction is processed by at least one of hydrotreating, hydrocracking, fluid catalytic cracking, alkylation, transalkylation, oxidation, or hydrogenation.