Systems, methods, and compositions for production of synthetic hydrocarbon compounds
A process and system for producing hydrocarbon compounds or fuels that recycle products of hydrocarbon compound combustion—carbon dioxide or carbon monoxide, or both, and water. The energy for recycling is electricity derived from preferably not fossil based fuels, like from nuclear fuels or from renewable energy. The process comprises electrolyzing water, and then using hydrogen to reduce externally supplied carbon dioxide to carbon monoxide, then using so produced carbon monoxide together with any externally supplied carbon monoxide and hydrogen in Fischer-Tropsch reactors, with upstream upgrading to desired specification fuels—for example, gasoline, jet fuel, kerosene, diesel fuel, and others. Energy released in some of these processes is used by other processes. Using adiabatic temperature changes and isothermal pressure changes for gas processing and separation, large amounts of required energy are internally recycled using electric and heat distribution lines. Phase conversion of working fluid is used in heat distribution lines for increased energy efficiency. The resulting use of electric energy is less than 1.4 times the amount of the high heating value of combustion of so produced hydrocarbon compounds when carbon dioxide is converted to carbon monoxide in the invention, and less than 0.84 when carbon monoxide is the source.
1. A system for producing hydrocarbon compounds comprising:
a) providing to a first reverse water gas shift reactor externally supplied hydrogen gas and carbon dioxide gas, wherein the molar ratio of hydrogen gas to carbon dioxide gas is greater than one, to generate a first syngas stream comprising a mixture of at least carbon monoxide gas and hydrogen gas, water steam, and residual carbon dioxide gas;
b) generating a second syngas stream from the first syngas stream by condensing and removing at least some water steam from the first syngas stream;
c) providing the second syngas stream to a second reverse water gas shift reactor to generate a third syngas stream comprising a mixture of at least carbon monoxide gas and hydrogen gas, water steam, and residual carbon dioxide;
d) generating a fourth syngas stream from the third syngas stream by condensing and removing at least some water steam from the third syngas stream, and;
e) generating a mixture of at least hydrocarbon compounds from at least the carbon monoxide gas and the hydrogen gas from the fourth syngas stream.
2. The process of claim 1 , wherein the operating temperatures of the first and second reverse water gas shift reactors are between 350° C and 500° C.
3. The process of claim 1 , wherein at least a portion of carbon dioxide is separated from the fourth stream of syngas before it is used in step e).
4. The process of claim 3 , wherein the separated carbon dioxide is supplied to at least one of the first or second reverse water gas shift reactors.
5. The process of claim 3 , wherein at least a portion of the separated carbon dioxide is supplied to the first reverse water gas shift reactor.
6. The process of claim 1 , wherein carbon dioxide is separated from the mixture generated in step e) and supplied to the first reverse water gas shift reactor.
7. The process of claim 1 , further comprising supplying carbon monoxide to step e) as a portion of a stream exiting from an optional reaction process that converts carbon dioxide to at least carbon monoxide.