System and Method for Converting Waste Polyolefins, Renewable Oils, and Paraffinic Crudes to Aromatic Compounds

Abstract

Feedstocks containing aliphatic moieties and at least 12 carbon atoms are contacted with a metallic process agent disposed on a substrate consisting of oxides of: aluminum; silica; titanium; zirconium; and/or aluminum and silica. The feedstocks and first process agent are maintained in a reactor at temperatures from about 325° C. to 450° C. for a duration of up to about 5 hours, to generate products containing aromatic compounds. The aromatic compounds are generated independently of any requirement for adding molecular hydrogen to the process system or for configuring the process system to deliberately accumulate and/or maintain a partial pressure of molecular hydrogen, and are recovered from the process mixture.

1 . A process for transforming aliphatic moieties in feedstocks into aromatic compounds, the process comprising:
 (a) providing one or more feedstocks containing aliphatic moieties and at least about 12 carbon atoms, wherein each of the aliphatic moieties includes at least six constituent carbon atoms disposed in a contiguous open-chain configuration, each of said at least six constituent carbon atoms bearing no more than one aliphatic substituent;   (b) providing a first process agent including one or more metals disposed on a substrate, the substrate including one or more of: oxides of aluminum; oxides of silicon;   oxides of titanium; oxides of zirconium; and combinations of oxides of aluminum and silicon;   (c) disposing the first process agent in a reactor;   (d) conveying the one or more feedstocks to the reactor and into contact with the first process agent, to form a process mixture in the reactor;   (e) maintaining, in the reactor, the process mixture at temperatures in a range T(range 1 ) from T(min) of about 325° C. to T(max) of about 450° C., to effect commencement of one or more desirable reactions within the process mixture;   (f) maintaining, in the reactor, the process mixture at temperatures in said T(range 1 ) for a residence time in a range t(range 2 ) of between t(min) of about 0.1 hours and t(max) of about 5 hours, wherein said temperatures and residence times are suitable to further promote the one or more desirable reactions in the process mixture to generate products containing aromatic compounds; and   (g) recovering, from the process mixture, the aromatic compounds, wherein the aromatic compounds are generated independently of any requirement for adding molecular hydrogen to the process system or for configuring the process system to deliberately accumulate and/or maintain a partial pressure of molecular hydrogen.   
     
     
         2 . The process of  claim 1 , wherein at least one of the at least six constituent carbon atoms in the aliphatic moieties bears a carboxylate group or a hydroxyl group. 
     
     
         3 . The process of  claim 2 , wherein (i) said hydroxyl-bearing carbon atoms may be primary, secondary, or tertiary, and (ii) said carboxylate groups relate to carboxylic acids and/or esters thereof. 
     
     
         4 . The process of  claim 1 , wherein said one or more desirable reactions include reactions of a first type, and/or reactions of a second type, and/or reactions of a third type, said one or more desirable reactions generating in the process mixture, intermediate products, and the aromatic product compounds. 
     
     
         5 . The process of  claim 1 , further comprising configuring the reactor as a plurality of communicably coupled reactors. 
     
     
         6 . The process of  claim 1 , wherein said maintaining (e) further comprises maintaining, in the reactor, the process mixture at said T(range 1 ), within a temperature variance T(var) of less than about 0.4×(T(max)−T(min)). 
     
     
         7 . The process of  claim 6 , wherein T(var) is less than about 0.2×(T(max)−T(min)). 
     
     
         8 . The process of  claim 6 , wherein T(var) is less than about 0.1×(T(max)−T(min)). 
     
     
         9 . The process of  claim 1 , wherein said maintaining (f) further comprises maintaining, in the reactor, the process mixture at said T(range 1 ) for a residence time in a range t(range 2 ), within a residence time variance t(var) of less than about 0.4×(t(min)−t(max)). 
     
     
         10 . The process of  claim 9 , wherein t(var) is less than about 0.2×(t(min)−t(max)). 
     
     
         11 . The process of  claim 9 , wherein (var) is less than about 0.1×(t(min)−t(max)). 
     
     
         12 . The process of  claim 1 , further comprising maintaining pressure in the process system between ambient pressure and 2000 psi. 
     
     
         13 . The process of  claim 1  wherein said providing (a) further comprises providing feedstocks that include one or more of: post-use plastics; waxes derived from post-use plastics; renewable oils; and paraffinic crude oils. 
     
     
         14 . The process of  claim 13  wherein the post-use plastics include polyethylene (PE) and/or polypropylene (PP), and the waxes derived from post-use plastics include oligomers of PE and/or of PP with carbon numbers between 25 to 250. 
     
     
         15 . The process of  claim 13  wherein said providing (a) further comprises providing post-use plastics including polybutadiene, poly(2-methylbutadiene), and/or poly(vinyl alcohol-co-ethylene). 
     
     
         16 . The process of  claim 15 , wherein the poly(vinyl alcohol-co-ethylene) includes ethylene and vinyl alcohol in a ratio of (moles vinyl alcohol)/(moles ethylene) that is less than about 0.35. 
     
     
         17 . The process of  claim 13  wherein renewable oils include mono-, di-, and/or triglycerides, and/or free fatty acids (FFA) derived from the renewable oils, and/or alkyl monoesters of the FFA. 
     
     
         18 . The process of  claim 17 , wherein the fatty acids derived from the renewable oils contain a hydroxyl group. 
     
     
         19 . The process of  claim 18 , wherein the fatty acids include 12-hydroxy oleic acid, which is ricinoleic acid. 
     
     
         20 . The process of  claim 13  wherein the paraffinic crude is Uinta Basin Crude. 
     
     
         21 . The process of  claim 1 , wherein the aromatic compounds include a benzenoid ring whose six carbon atoms derive from the at least six carbon atoms in the aliphatic moieties and bear either hydrogen or an aliphatic substituent. 
     
     
         22 . The process of  claim 21 , wherein the aromatic compounds include a plurality of the aliphatic substituents on the benzenoid ring. 
     
     
         23 . The process of  claim 21 , wherein the aliphatic substituent includes (i) any aliphatic group taken from the group consisting essentially of alkyl groups including methyl, ethyl, and larger alkyl groups containing three to about 20 carbon atoms and/or (ii) any alkenyl group containing two to about 20 carbon atoms and at least one unsaturation; and wherein the total number of carbons in all substituents is zero to about 25. 
     
     
         24 . The process of  claim 21 , wherein the aromatic compounds include one or more of benzene, toluene, o-xylene, m-xylene, p-xylene, mesitylene, ethylbenzene, and cumene. 
     
     
         25 . The process of  claim 21 , wherein the aromatic compounds include a mixture including benzene and/or toluene and/or ethylbenzene and/or xylenes (BTEX). 
     
     
         26 . The process of  claim 1 , wherein the one or more metals include: (i) metals in groups  2 - 10  of periods  4 ,  5 , and  6  of the periodic table of the elements, excluding platinum and palladium; and/or (ii) lanthanides. 
     
     
         27 . The process of  claim 26 , wherein the one or more metals include molybdenum and/or nickel. 
     
     
         28 . The process of  claim 26 , wherein each of the one or more metals has a positive oxidation number and exists in the form of a corresponding oxide. 
     
     
         29 . The process of  claim 26 , wherein each of the one or more metals exists in elemental form whose oxidation number is zero. 
     
     
         30 . The process of  claim 1 , wherein the substrate includes aluminosilicate compounds having a formula of M w [(AlO 2 ) x (SiO 2 ) y ]·zH 2 O and/or M w [(Al 2 O 3 ) x (SiO 2 ) y ] ·zH 2 O, wherein: w, x, y, and z have values of, respectively, 0 to about 10, about 2 to 25, about 2 to 100, and 1 to about 40; and M is one or more cations corresponding to elements taken from groups I and II of the periodic table of the elements, including hydrogen (H + ), sodium (Na + ), potassium (K + ), calcium (Ca 2+ ), magnesium (Mg +2 ), and/or barium (Ba 2+ ). 
     
     
         31 . The process of  claim 1 , wherein the substrate includes zirconium silicate, ZrSiO 4 . 
     
     
         32 . The process of  claim 30 , wherein the substrate includes one or more of zeolites, bentonite clay, kaolin clay, and/or montmorillonite clay. 
     
     
         33 . The process of  claim 30 , wherein w=z=0, x>0, and y>0; and the aluminosilicate compound is an aluminum silicate. 
     
     
         34 . The process of  claim 32 , wherein the zeolite is ZSM-5. 
     
     
         35 . The process of  claim 30 , wherein the values of w, x, and z are equal to zero and the substrate is silica. 
     
     
         36 . The process of  claim 30 , wherein the values of w, y, and z are equal to zero and the substrate is alumina or aluminum oxide. 
     
     
         37 . The process of  claim 4 , wherein the reactions of the first type yield intermediate products through one or more bond scission events in or at aliphatic moieties including one or more of those between (i) two adjacent saturated carbon atoms contained in the feedstocks; and/or (ii) a hydrogen atom and a carbon atom on each of two adjacent saturated carbon atoms; and/or (iii) the carbon-oxygen bond of a hydroxyl-bearing carbon and a carbon-hydrogen bond of the adjacent carbon in aliphatic moieties; and/or (iv) a carbon atom in the aliphatic moieties and a carboxylate group appended thereto. 
     
     
         38 . The process of  claim 37 , wherein the intermediate products include aliphatic moieties capable of further undergoing the reactions of a first type, the reactions of a second type, and the reactions of a third type. 
     
     
         39 . The process of  claim 38 , wherein the reactions of the second type obtain intermediate products having cyclic aliphatic moieties derived from the feedstocks and/or from the intermediate products. 
     
     
         40 . The process of  claim 38 , wherein the reactions of the third type obtain aromatic moieties from the feedstocks and/or from the intermediate products. 
     
     
         41 . The process of  claim 40 , wherein the reactions of the third type obtain aromatic compounds. 
     
     
         42 . The process of  claim 40 , wherein the reactions of the third type obtain intermediate products including a plurality of aromatic moieties bonded to a common aliphatic moiety. 
     
     
         43 . The process of  claim 42 , wherein the reactions of a first type relative to said common aliphatic moieties obtain aromatic compounds having a single aromatic moiety. 
     
     
         44 . The process of  claim 13  further comprising disposing a second process agent in the reactor along with the feedstock and the first process agent. 
     
     
         45 . The process of  claim 44 , wherein the second process agent: enables one or more desirable reactions of a fourth type; suppresses one or more undesirable reactions; and said agent is water. 
     
     
         46 . The process of  claim 45 , comprising applying the second process agent in amounts of about 1.1 to 1.5 times the stoichiometric requirement of the one or more desirable and undesirable reactions. 
     
     
         47 . The process of  claim 45 , wherein said desirable reactions of a fourth type include addition of water to an ester attached to the aliphatic moieties. 
     
     
         48 . The process of  claim 47 , wherein the ester is a renewable oil consisting of one or more fatty acid esters taken from the group consisting of mono-, di-, and triacyl glycerols, and mono-alkyl esters including methyl-, ethyl-, propyl-, and butyl esters; and wherein the desirable reactions of a fourth type obtain free fatty acids and glycerol and/or an alcohol including methanol, ethanol, propanol, and/or butanol. 
     
     
         49 . The process of  claim 45 , wherein the one or more undesirable reactions include the dehydration of glycerol to form acrolein and the polymerization of the same to form polyacrolein as a byproduct. 
     
     
         50 . The process of  claim 45 , wherein the desirable reactions of the fourth type include the combining of water with a monohydric alcohol and/or a polyhydric alcohol and said combining is in situ aqueous reforming that yields carbon dioxide and hydrogen in the form of hydrogen equivalents. 
     
     
         51 . The process of  claim 50 , wherein the monohydric and/or polyhydric alcohols include one or more of methanol, ethanol, glycerol, and ethylene glycol. 
     
     
         52 . The process of  claim 50 , wherein hydrogen equivalents include latent forms of hydrogen and molecular hydrogen. 
     
     
         53 . The process of  claim 45 , wherein the desirable reactions of the fourth type include the combining with water with hydrogen-deficient carbonaceous materials and/or incipient forms thereof whose general formula is C u H v  wherein u>v and, the ratio u/v is greater than about 1.25, said hydrogen-deficient carbonaceous materials are byproducts from undesirable reactions involving the feedstocks or compounds derived therefrom, and said combining is in situ aqueous reforming that yields carbon dioxide and hydrogen equivalents, which include latent forms of hydrogen and molecular hydrogen. 
     
     
         54 . The process of  claim 44 , further comprising conveying a third process agent into the reactor together with the feedstocks in amounts of about 0.1 to 1.5 relative to feedstock mass. 
     
     
         55 . The process of  claim 54 , wherein the third process agent is one or more taken from the group consisting of water; carbon dioxide; one or more aromatic compounds containing nine or fewer carbons, including benzene and mono-, di-, and tri-methyl benzene; and one or more alkanes with three to five carbons. 
     
     
         56 . The process of  claim 1 , wherein said providing (a) further comprises configuring the reactor as a tank reactor. 
     
     
         57 . The process of  claim 1 , wherein said providing (a) further comprises configuring the reactor as a flow-through tank reactor. 
     
     
         58 . The process of  claim 1 , wherein said providing (a) further comprises configuring the reactor as a tubular reactor, said providing (b) further comprises configuring the catalyst as a fixed bed in the tubular reactor, and said conveying (d) further comprises flowing the feedstock through the reactor. 
     
     
         59 . The process of  claim 54 , comprising controlling rates at which the feedstock and third agent are conveyed into the reactor to provide a residence time of the reaction mixture in the reactor of about 0.1 to 4 hours. 
     
     
         60 . A system for transforming aliphatic moieties in feedstocks into aromatic compounds, the system comprising:
 a reactor sized and shaped to receive one or more feedstocks therein containing aliphatic moieties and at least about 12 carbon atoms, wherein each of the aliphatic moieties includes at least six constituent carbon atoms disposed in a contiguous open-chain configuration, each of said at least six constituent carbon atoms bearing no more than one aliphatic substituent;   a first process agent disposed within the reactor, the first process agent including one or more metals disposed on a substrate, the substrate including one or more of: oxides of aluminum; oxides of silica; oxides of titanium; oxides of zirconium; and combinations of oxides of aluminum and silica;   the reactor configured to maintain the one or more feedstocks in contact with the first process agent, to form a process mixture in the reactor;   the reactor configured to maintain the process mixture at temperatures in a range T(range 1 ) from T(min) of about 325° C. to T(max) of about 450° C., to effect commencement of one or more desirable reactions within the process mixture;   the reactor configured to maintain the process mixture at temperatures in said T(range 1 ) for a residence time in a range t(range 2 ) of between t(min) of about 0.1 hours and t(max) of about 5 hours, wherein said temperatures and residence times are suitable to further promote the one or more desirable reactions in the process mixture to generate products containing aromatic compounds; and   the system configured to recover, from the reactor, the aromatic compounds, wherein the aromatic compounds are generated independently of any requirement for adding molecular hydrogen to the process system or for configuring the process system to deliberately accumulate and/or maintain a partial pressure of molecular hydrogen.   
     
     
         61 . The system of  claim 60 , further configured to maintain, in the reactor, the process mixture at said T(range 1 ), within a temperature variance T(var) of less than about 0.4×(T(max)−T(min)). 
     
     
         62 . The system of  claim 60 , wherein the one or more metals include: (i) metals in groups  2 - 10  of periods  4 ,  5 , and  6  of the periodic table of the elements, excluding platinum and palladium; and/or (ii) lanthanides. 
     
     
         63 . The system of  claim 60 , wherein the reactor comprises a tank reactor. 
     
     
         64 . The system of  claim 63 , wherein the reactor comprises a flow-through tank reactor. 
     
     
         65 . The system of  claim 60 , wherein the reactor comprises a tubular reactor and the catalyst is configured as a fixed bed. 
     
     
         66 . The system of  claim 60 , further comprising a phase separator communicably coupled to the reactor to receive and collect the aromatic compounds. 
     
     
         67 . The system of  claim 60 , further comprising a pressure regulator and condenser communicably coupled to the reactor and the phase separator.