Process for converting hydrocarbon feedstocks with electrolytic recovery of halogen

Abstract

An improved continuous process for converting methane, natural gas, and other hydrocarbon feedstocks into one or more higher hydrocarbons, methanol, amines, or other products comprises continuously cycling through hydrocarbon halogenation, product formation, product separation, and electrolytic regeneration of halogen, optionally using an improved electrolytic cell equipped with an oxygen depolarized cathode.

1 . A continuous process for converting a hydrocarbon feedstock into higher hydrocarbons, comprising:
 (a) forming alkyl halides by reacting molecular halogen with a hydrocarbon feedstock under process conditions sufficient to form alkyl halides and hydrogen halide, optionally with substantially complete consumption of the molecular halogen;   (b) forming higher hydrocarbons and hydrogen halide by contacting the alkyl halides with a first catalyst under process conditions sufficient to form higher hydrocarbons and hydrogen halide;   (c) separating the higher hydrocarbons from hydrogen halide;   (d) converting the hydrogen halide into hydrogen and molecular halogen electrolytically, thereby allowing the halogen to be reused; and   (e) repeating steps (a) through (d) a desired number of times.   
     
     
         2 . A continuous process as recited in  claim 1 , wherein the hydrocarbon feedstock comprises natural gas. 
     
     
         3 . A continuous process as recited in  claim 1 , wherein the hydrocarbon feedstock comprises methane. 
     
     
         4 . A continuous process as recited in  claim 1 , wherein electrolysis is carried out in aqueous media. 
     
     
         5 . A continuous process as recited in  claim 1 , wherein electrolysis is carried out in the gas phase. 
     
     
         6 . A continuous process as recited in  claim 1 , wherein the higher hydrocarbons comprise fuel grade hydrocarbons and/or aromatic hydrocarbons. 
     
     
         7 . A continuous process as recited in  claim 6 , wherein the aromatic hydrocarbons comprise benzene, toluene, and xylenes. 
     
     
         8 . A continuous process for converting a hydrocarbon feedstock into methanol, comprising:
 (a) forming alkyl halides by reacting molecular halogen with a hydrocarbon feedstock under process conditions sufficient to form alkyl halides and hydrogen halide, optionally with substantially complete consumption of the molecular halogen;   (b) forming methanol and alkaline halide by contacting the alkyl halides with aqueous alkali under process conditions sufficient to form methanol and alkaline halide;   (c) separating the methanol from the alkaline halide;   (d) converting the alkaline halide into hydrogen, molecular halogen, and aqueous alkali electrolytically, thereby allowing the halogen and the alkali to be reused; and   (e) repeating steps (a) through (d) a desired number of times.   
     
     
         9 . A continuous process as recited in  claim 8 , wherein the hydrocarbon feedstock comprises natural gas. 
     
     
         10 . A continuous process as recited in  claim 8 , wherein the hydrocarbon feedstock comprises methane. 
     
     
         11 . A continuous process as recited in  claim 8 , wherein electrolysis is carried out in aqueous media. 
     
     
         12 . A continuous process as recited in  claim 8 , wherein electrolysis is carried out in the gas phase. 
     
     
         13 . A continuous process for converting a hydrocarbon feedstock into an alkyl amine, comprising:
 (a) forming alkyl halides by reacting molecular halogen with a hydrocarbon feedstock under process conditions sufficient to form alkyl halides and hydrogen halide, optionally with substantially complete consumption of the molecular halogen;   (b) forming alkyl amines and alkaline halide by contacting the alkyl halides with aqueous alkaline amine under process conditions sufficient to form alkyl amines and alkaline halide;   (c) separating the alkyl amines from the alkaline halide;   (d) converting the alkaline halide into hydrogen and molecular halogen electrolytically, thereby allowing the halogen to be reused; and   (e) repeating steps (a) through (d) a desired number of times.   
     
     
         14 . A continuous process as recited in  claim 12 , wherein, wherein the alkaline amine comprises NaNH 2 . 
     
     
         15 . A continuous process as recited in  claim 12 , wherein the alkyl halides comprise ethyl bromide, the alkaline amines comprise NaNH 2 , and the alkyl halides comprise ethyl bromide. 
     
     
         16 . In a production facility where oil or gas is pumped from a well and thereby extracted from the earth, and having an electrical generator or electrical power supply, the improvement comprising:
 (a) forming alkyl halides by reacting molecular halogen with oil or gas pumped from the well, under process conditions sufficient to form alkyl halides and hydrogen halide, optionally with substantially complete consumption of the molecular halogen;   (b) forming higher hydrocarbons and hydrogen halide by contacting the alkyl halides with a first catalyst under process conditions sufficient to form higher hydrocarbons and hydrogen halide;   (c) separating the higher hydrocarbons from hydrogen halide; and   (d) converting the hydrogen halide into hydrogen and molecular halogen electrolytically, using electricity provided by the electrical generator or electrical power supply, thereby allowing the halogen to be reused.   
     
     
         17 . The improvement as recited in  claim 16 , wherein the oil or gas production facility is located offshore. 
     
     
         18 . In a production facility where oil or gas is pumped from a well and thereby extracted from the earth, and having an electrical generator or electrical power supply, the improvement comprising:
 (a) forming alkyl halides by reacting molecular halogen with a hydrocarbon feedstock under process conditions sufficient to form alkyl halides and hydrogen halide, optionally with substantially complete consumption of the molecular halogen;   (b) forming methanol and alkaline halide by contacting the alkyl halides with aqueous alkali under process conditions sufficient to form methanol and alkaline halide;   (c) separating the methanol from the alkaline halide;   (d) converting the alkaline halide into hydrogen, molecular halogen, and aqueous alkali electrolytically, using electricity provided by the electrical generator or electrical power supply, thereby allowing the halogen and the alkali to be reused.   
     
     
         19 . The improvement as recited in  claim 18 , wherein the oil or gas production facility is located offshore. 
     
     
         20 . A continuous process for converting coal into coke and hydrogen, comprising:
 (a) forming brominated coal intermediates coke and hydrogen halide by reacting crushed coal with molecular halogen under process conditions sufficient to form brominated coal intermediates and hydrogen halide;   (b) forming coke and hydrogen halide by reacting the brominated coal intermediates over a catalyst under process conditions sufficient to form coke and hydrogen halide;   (c) separating the coke from the hydrogen halide;   (d) converting the hydrogen halide found in step (a) and/or step (b) into hydrogen and molecular halogen electrolytically, thereby allow the halogen to be reused; and   (e) repeating steps (a) through (e) a desired number of times.   
     
     
         21 . A continuous process for converting coal or biomass-derived hydrocarbons into polyols, comprising:
 (a) forming alkyl halides by reacting molecular halogen with coal or a biomass-derived hydrocarbon feedstock under process conditions sufficient to form alkyl halides and hydrogen halide, optionally with substantially complete consumption of the molecular halogen;   (b) forming polyols and alkaline halide by contacting the alkyl halides with aqueous alkali under process conditions sufficient to form polyols and alkaline halide;   (c) separating the polyol(s) from the alkaline halide;   (d) converting the alkaline halide into hydrogen and molecular halogen electrolytically, thereby allowing the halogen to be reused; and   (e) repeating steps (a) through (d) a desired number of times.   
     
     
         22 . A continuous process for converting a hydrocarbon feedstock into higher hydrocarbons, comprising:
 (a) forming alkyl halides by reacting molecular halogen with a hydrocarbon feedstock under process conditions sufficient to form alkyl halides and hydrogen halide, optionally with substantially complete consumption of the molecular halogen;   (b) forming higher hydrocarbons and hydrogen halide by contacting the alkyl halides with a first catalyst under process conditions sufficient to form higher hydrocarbons and hydrogen halide;   (c) separating the higher hydrocarbons from hydrogen halide;   (d) converting the hydrogen halide into water and molecular halogen in an electrolytic cell or cells equipped with an oxygen depolarized cathode, thereby allowing the halogen to be reused; and   (e) repeating steps (a) through (d) a desired number of times.   
     
     
         23 . A continuous process for converting a hydrocarbon feedstock into methanol, comprising:
 (a) forming alkyl halides by reacting molecular halogen with a hydrocarbon feedstock under process conditions sufficient to form alkyl halides and hydrogen halide, optionally with substantially complete consumption of the molecular halogen;   (b) forming methanol and alkaline halide by contacting the alkyl halides with aqueous alkali under process conditions sufficient to form methanol and alkaline halide;   (c) separating the methanol from the alkaline halide;   (d) converting the alkaline halide into molecular halogen and aqueous alkali in an electrolytic cell or cells equipped with an oxygen depolarized cathode, thereby allowing the halogen and the alkali to be reused; and   (e) repeating steps (a) through (d) a desired number of times.   
     
     
         24 . An electrolytic cell for converting a halide into molecular halogen, comprising:
 a gas supply manifold through which oxygen gas, air, or oxygen-enriched air can be introduced;   a gas diffusion cathode, which is permeable to oxygen or an oxygen-containing gas;   a cation exchange membrane;   a cathode electrolyte chamber disposed between the cation exchange membrane and the gas diffusion cathode;   an anode electrolyte chamber; and   an anode extending into the anode electrolyte chamber.   
     
     
         25 . A method for converting a halide into molecular halogen, comprising:
 providing an electrolytic cell comprising a gas supply manifold, a gas diffusion cathode that is permeable to oxygen or an oxygen-containing gas, a cation exchange membrane, a cathode electrolyte chamber disposed between the cation exchange membrane and the gas diffusion cathode, an anode electrolyte chamber, and an anode extending into the anode electrolyte chamber;   introducing water into the cathode electrolyte chamber;   introducing oxygen or an oxygen-containing gas into the gas supply manifold introducing aqueous alkaline halide into the anode electrolyte chamber;   supplying electrical power to the cell;   forming bromine gas by reducing alkaline bromide at the anode;   forming alkaline hydroxide by reducing oxygen at the cathode;   removing aqueous alkaline hydroxide from the cathode electrolyte chamber; and   removing molecular bromine from the anode electrolyte chamber.   
     
     
         26 . A method as recited in  claim 25 , wherein the alkaline halide comprises sodium bromide. 
     
     
         27 . A method as recited in  claim 25 , wherein the alkaline hydroxide comprises sodium hydroxide.