Coal dust treatment methods and compositions

Abstract

Methods and compositions for treating coal are provided. A nitroxyl radical compound is added to the coal in order to inhibit coal autooxidation. Additionally, the nitroxyl radical compound can be conjointly used with conventional dust control agents, in order to suppress fugitive coal dust dissemination. In those cases in which foamed treatment is desired to treat coal dust, the nitroxyl radical compound can be conjointly used in the foamable compositions, along with a variety of foam building surfactants such as the amphoteric, nonionic and anionic surfactants.

1 . A method of treating coal comprising adding a nitroxyl radical compound (NRC) to said coal. 
     
     
         2 . The method of  claim 1 , wherein the NRC has the following structure: 
       
         
           
           
               
               
           
         
         wherein 
         R 2 , R 3 , R 8 , R 9  are each independently of one another substituted or un-substituted C 1 -C 18  alkyl, C 2 -C 18  alkenyl, or C 2 -C 18  alkynyl; or 
         R 2  and R 3  and/or R 8  and R 9  together form, with the linking carbon, a C 3 -C 12  cycloalkyl radical; and 
         R 4 , R 5 , R 6 , R 7  are each independently of one another hydrogen, substituted or un-substituted C 1 -C 18  alkyl, C 2 -C 18  alkenyl, or C 2 -C 18  alkynyl; 
         X is —O—, —C(O)—, ═O, —NR 10 — or —NR 10 —C(O)—; wherein 
         R 10  is hydrogen, phenyl, or C 1 -C 18  alkyl; and wherein 
         R 1  is hydrogen, phenyl, substituted or un-substituted C 1 -C 18  alkyl, C 2 -C 18  alkenyl, or C 2 -C 18  alkynyl. 
       
     
     
         3 . A method as recited in  claim 1  wherein said NRC is added to said coal in an amount of about 0.001 to 10 lbs, per ton of coal. 
     
     
         4 . A method as recited in  claim 1  wherein said NRC is selected from the group consisting of dialkyl nitroxyl radicals, 1-oxyl-2,2,6,6-tetraalkylpiperidine compounds, 1-oxyl-2,2,6,6-tetramethylpiperidine, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-ol (4-HT), 1-oxyl-2,2,6,6-tetramethylpiperidin-4-one, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl acetate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl-2-ethylhexanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl stearate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl benzoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl 4-tert-butylbenzoate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)succinate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)adipate, bis(1-oxyl-2,2,6,6-tetramethypiperidin-4-yl)sebacate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)n-butylmalonate, bis(1-oxyl-2,2,6,6-tetramethylpiperadin-4-yl)phthalate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)isophthalate, bis(1-oxyl-2,2,6,6-tetramethyl piperidinyl-4-yl)terephthalate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)hexahydroterephthalate, N,N′-bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)adipamide, N-1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl-dodecyl succinimide, 1-oxyl-4-methoxy-2,2,6,6-tetramethylpiperidine, 1-oxyl-4-amino-2,2,6,6-tetramethylpiperidine, 4-butoxy-2,2,6,6-tetramethylpiperidine and 1-oxyl-4-acetamino-2,2,6,6-tetramethyl piperidine and derivatives thereof. 
     
     
         5 . A method as recited in  claim 4  wherein said NRC is 1-oxyl-2,2,6,6-tetramethylpiperdin-4-ol (4HT). 
     
     
         6 . A method as recited in  claim 1  wherein said method further comprises adding a foaming agent selected from amphoteric, nonionic and anionic surfactants to said coal. 
     
     
         7 . A method as recited in  claim 6  wherein said foaming agent comprises an anionic surfactant. 
     
     
         8 . A method as recited in  claim 7  wherein said anionic surfactant comprises an alkane sulfonate or an alkenyl sulfonate. 
     
     
         9 . A method as recited in  claim 1  wherein said method further comprises adding a dust control agent (DCA) to said coal. 
     
     
         10 . A method as recited in  claim 9  wherein said DCA comprises a polymer. 
     
     
         11 . A method as recited in  claim 10  wherein said polymer is a member selected from the group consisting of i) polymers containing two or more of epichlorohydrin, polyalkylene polyamine, and adipic acid monomers, ii) aminoalkylated polyacrylamides, and iii) quaternary ammonium polymers or copolymers. 
     
     
         12 . A method as recited in  claim 11  wherein said i) polymers containing two or more of epichlorohydrin, polyalkylene polyamine, and adipic acid monomers comprise diethyltriamine, adipic acid, and epichlorohydrin monomers, wherein said ii) aminoalkylated polyacrylamides comprise aminomethylated polyacrylamides, and wherein the iii) quaternary ammonium polymers or copolymers comprise a reaction product of quaternaryamine, dimethylamine, and epicholohydrin. 
     
     
         13 . A composition comprising a) a nitroxyl radical composition (NRC) and one or more of b) dust control agent and c) foaming agent, wherein if a) and b) are present, for every 1-5 parts of a), there are 1-100 parts of b), and wherein if a) and c) are present, for every 1-5 parts of a) there are 0.01-10 parts of c), and wherein if all three of a) and b) and c) are present, for every 1-5 parts of a) there are 1-100 parts of b) and 0.01-10 parts of c). 
     
     
         14 . A composition as recited in  claim 13 , wherein the NRC has the following structure: 
       
         
           
           
               
               
           
         
         wherein 
         R 2 , R 3 , R 8 , R 9  are each independently of one another substituted or un-substituted C 1 -C 18  alkyl, C 2 -C 18  alkenyl, or C 2 -C 18  alkynyl; or 
         R 2  and R 3  and/or R 8  and R 9  together form, with the linking carbon, a C 3 -C 12  cycloalkyl radical; and 
         R 4 , R 5 , R 6 , R 7  are each independently of one another hydrogen, substituted or un-substituted C 1 -C 18  alkyl, C 2 -C 18  alkenyl, or C 2 -C 18  alkynyl; 
         X is —O—, —O—C(O)—, ═O, —NR 10 — or —NR 10 —C(O)—; wherein 
         R 10  is hydrogen, phenyl, or C 1 -C 18  alkyl; and wherein 
         R 1  is hydrogen, phenyl, substituted or un-substituted C 1 -C 18  alkyl, C 2 -C 18  alkenyl, or C 2 -C 18  alkynyl. 
       
     
     
         15 . A composition as recited in  claim 13  wherein said a) NRC is selected from the group consisting of dialkyl nitroxyl radicals, 1-oxyl-2,2,6,6-tetraalkylpiperidine compounds, 1-oxyl-2,2,6,6-tetramethylpiperidine, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-ol (4-HT), 1-oxyl-2,2,6,6-tetramethylpiperidin-4-one, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl acetate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl-2-ethylhexanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl stearate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl benzoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl 4-tert-butylbenzoate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)succinate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)adipate, bis(1-oxyl-2,2,6,6-tetramethypiperidin-4-yl)sebacate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)n-butylmalonate, bis(1-oxyl-2,2,6,6-tetramethylpiperadin-4-yl)phthalate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)isophthalate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)terephthalate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)hexahydroterephthalate, N,N′-bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)adipamide, N-1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl-dodecyl succinimide, 1-oxyl-4-methoxy-2,2,6,6-tetramethylpiperidine, 1-oxyl-4-amino-2,2,6,6-tetramethylpiperidine, 4-butoxy-2,2,6,6-tetramethylpiperidine and 1-oxyl-4-acetamino-2,2,6,6-tetramethylpiperidine and derivatives thereof. 
     
     
         16 . A composition as recited in  claim 15  wherein said NRC is 1-oxyl-2,2,6,6-tetramethypiperidin-4-ol (4HT). 
     
     
         17 . A composition as recited in  claim 13 , wherein the foaming agent is selected from amphoteric, nonionic and anionic surfactants. 
     
     
         18 . A composition as recited in  claim 17 , wherein the foaming agent comprises an anionic surfactant. 
     
     
         19 . A composition as recited in  claim 18 , wherein the anionic surfactant comprises an alkane sulfonate or an alkenyl sulfonate. 
     
     
         20 . A composition as recited in  claim 13 , wherein said dust control agent comprises a polymer. 
     
     
         21 . A composition as recited in  claim 20 , wherein said polymer is a member selected from the group consisting of i) polymers containing two or more of epichlorohydrin, polyalkylene polyamine, and adipic acid monomers, ii) aminoalkylated polyacrylamides, and iii) quaternary ammonium polymers or copolymers. 
     
     
         22 . A composition as recited in  claim 21 , wherein said i) polymers containing two or more of epichlorohydrin, polyalkylene polyamine, and adipic acid monomers comprise diethyltriamine, adipic acid, and epichlorohydrin monomers, wherein said ii) aminoalkylated polyacrylamides comprise aminomethylated polyacrylamides, and wherein the iii) quaternary ammonium polymers or copolymers comprise a reaction product of quaternaryamine, dimethylamine, and epicholohydrin. 
     
     
         23 . A composition comprising coal and a) a nitroxyl radical composition (NRC) and one or more of b) dust control agent and c) foaming agent, wherein if a) and b) are present, for every 1-5 parts of a), there are 1-100 parts of b), and wherein if a) and c) are present, for every 1-5 parts of a) there are 0.01-10 parts of c), and wherein if all three of a) and b) and c) are present, for every 1-5 parts of a) there are 1-100 parts of b) and 0.01-10 parts of c), and wherein a) is present in an amount of about 0.001 to 10 lbs per ton of the coal. 
     
     
         24 . A method of treating coal comprising adding a quaternary ammonium compound to said coal. 
     
     
         25 . The method of  claim 24  wherein the quaternary ammonium compound is quaternaryamine/dimethylamine/epichlorohydrin. 
     
     
         26 . A method of treating coal comprising adding an amine functionalized tannin to said coal. 
     
     
         27 . The method of  claim 26 , wherein the amine functionalized tannin is tannin/monoethanolamine/formaldehyde.