Apparatus and methods for the production of ammonia and Fischer-Tropsch liquids

1. A method for producing desired relative amounts of ammonia and liquid hydrocarbons, the ammonia produced via steam methane reforming and the liquid hydrocarbons produced via Fischer-Tropsch reaction, the method comprising:

introducing a carbonaceous raw material, water and oxygen into a synthesis gas generator under synthesis gas forming operating conditions to form a synthesis gas;

separating the synthesis gas into a first portion of synthesis gas that is used for Fischer-Tropsch conversion and a second portion of synthesis gas that bypasses Fischer-Tropsch conversion;

introducing the first portion of synthesis gas from the synthesis gas generator into a Fischer-Tropsch reactor and forming Fischer-Tropsch liquid hydrocarbons and tail gas comprising carbon dioxide, unreacted carbon monoxide, and gaseous hydrocarbons;

compressing the tail gas to an elevated pressure, thereby forming a compressed gas;

introducing the compressed gas together with steam into a steam methane reformer, thereby producing a reformer effluent comprising hydrogen, carbon monoxide, and carbon dioxide;

combining the second portion of the synthesis gas with the reformer effluent to form a gas mixture;

introducing the gas mixture into one or more shift reactors to convert carbon monoxide and water to hydrogen and carbon dioxide;

converting unreacted CO and CO 2 to methane using a methanator, thereby forming a methanator effluent comprising hydrogen and methane;

introducing the methanator effluent together with nitrogen into an ammonia synthesis reactor to produce ammonia and a purge gas stream comprising hydrogen; and

adjusting the production of Fischer-Tropsch liquid hydrocarbons relative to the production of ammonia by adjusting the amount of synthesis gas in the second bypass portion of synthesis gas.

2. The method of claim 1 further comprising, prior to separating the synthesis gas into first and second portions, cooling the synthesis gas to condense and remove water; and removing sulfur compounds and carbon dioxide from the synthesis gas using an acid gas removal system, thereby forming a cleaned synthesis gas.

3. The method of claim 1 further comprising pretreating the compressed gas in an adiabatic pre-reformer.

4. The method of claim 1 further comprising introducing the purge gas stream comprising hydrogen into a hydrogen membrane separator to produce a stream of hydrogen-rich gas and a stream of hydrogen-lean gas; feeding the hydrogen-lean gases to a heat recovery steam generator to drive a generator mechanically coupled to a steam turbine during a production of electricity.

5. The method of claim 4 further comprising:

compressing the hydrogen-rich gases to an elevated pressure;

introducing the compressed hydrogen-rich gases into a pressure swing adsorption unit to produce a stream of high purity hydrogen; and

introducing the high-purity hydrogen into a reactor to upgrade separated liquid hydrocarbons by hydrotreating.

6. The method of claim 1 further comprising removing carbon dioxide from the shifter effluent prior to converting unreacted CO and CO 2 to methane using the methanator; wherein removing carbon dioxide from the shifter effluent comprises using an absorption system to form a highly concentrated hydrogen stream comprising trace amounts of CO and CO 2 .

7. The process of claim 1 wherein the steam methane reformer; the one or more shift reactors, the absorption system, the methanator, and the ammonia synthesis reactor form an ammonia loop of an existing ammonia production plant.

8. A method for producing desired relative amounts of ammonia and Fischer-Tropsch liquid hydrocarbons, the method comprising:

introducing a carbonaceous raw material, water and oxygen into a synthesis gas generator under synthesis gas forming operating conditions to form a synthesis gas;

separating the synthesis gas into a first portion of synthesis gas that is used for Fischer-Tropsch conversion and a second portion of synthesis gas that bypasses Fischer-Tropsch conversion;

introducing the first portion of the cleaned synthesis gas into a Fischer-Tropsch reactor and forming product comprising primarily aliphatic hydrocarbons and carbon dioxide;

separating Fischer-Tropsch liquid hydrocarbons from Fischer-Tropsch tail gas from the Fischer-Tropsch reactor product, the tail gas comprising unreacted carbon monoxide, carbon dioxide, and gaseous hydrocarbons;

combining the second portion of the synthesis gas with the Fischer-Tropsch tail gas to form a gas mixture;

compressing the gas mixture to an elevated pressure, thereby forming a compressed mixture;

introducing the compressed mixture together with steam into one or more shift reactors to convert a portion of the carbon monoxide and water to hydrogen and carbon dioxide;

introducing the shifted gases into a hydrogen membrane separator to produce a stream of hydrogen-rich gases and a stream of hydrogen-lean gases;

compressing the hydrogen-rich gases to an elevated pressure;

introducing the compressed hydrogen-rich gases into a pressure swing adsorption unit to produce a stream of high purity hydrogen;

introducing at least a portion of the high-purity hydrogen together with nitrogen into a reactor to produce ammonia; and

adjusting the production of Fischer-Tropsch liquid hydrocarbons relative to the production of ammonia by adjusting the amount of synthesis gas in the second bypass portion of synthesis gas.

9. The method of claim 8 further comprising burning the hydrogen-lean gases in a gas turbine combustor of a combined cycle plant to drive a generator mechanically coupled to a gas turbine during a production of electricity.

10. The method of claim 8 further comprising, prior to separating the synthesis gas into first and second portions, cooling the synthesis gas to condense and remove water; and removing sulfur compounds and carbon dioxide from the synthesis gas using an acid gas removal system, thereby forming a cleaned synthesis gas.

11. The method of claim 10 wherein the step of removing sulfur compounds and carbon dioxide from the synthesis gas further comprises introducing hydrogen sulfide into a sulfur recovery system to produce sulfur.

12. The method of claim 10 further comprising removing carbon dioxide from the shifted gases prior to introducing the shifted gases into a hydrogen membrane separator to produce a stream of hydrogen-rich gases and a stream of hydrogen-lean gases.

13. The method of claim 10 further comprising the step of introducing a portion of the stream of high-purity hydrogen into a reactor to upgrade the liquid hydrocarbons by hydrotreating.

14. A method of reducing carbon dioxide vented into the air during production of Fischer-Tropsch liquid hydrocarbons via Fischer-Tropsch reaction and production of ammonia via steam methane reforming, the method comprising:

introducing a carbonaceous raw material, water and oxygen into a synthesis gas generator under synthesis gas forming operating conditions to form a synthesis gas;

cooling the synthesis gas to condense and remove water;

removing sulfur compounds and a first stream of carbon dioxide from the synthesis gas using an acid gas removal system, thereby forming a cleaned synthesis gas;

separating the cleaned synthesis gas into a first portion of synthesis gas that is used for Fischer-Tropsch conversion and a second portion of synthesis gas that bypasses Fischer-Tropsch conversion;

introducing the first portion of synthesis gas from the synthesis gas generator into a Fischer-Tropsch reactor and forming Fischer-Tropsch liquid hydrocarbons and tail gas comprising carbon dioxide, unreacted carbon monoxide, and gaseous hydrocarbons;

compressing the tail gas to an elevated pressure, thereby forming a compressed gas;

introducing the compressed gas together with steam into a steam methane reformer, thereby producing a reformer effluent comprising hydrogen, carbon monoxide, and carbon dioxide;

combining the second portion of the synthesis gas with the reformer effluent to form a gas mixture;

introducing the gas mixture into one or more shift reactors to convert carbon monoxide and water to hydrogen and carbon dioxide;

removing a second portion of carbon dioxide from the shifter effluent using an absorption system, thereby forming a highly concentrated hydrogen stream comprising trace amounts of CO and CO 2 ;

converting the CO and CO 2 to methane using a methanator, thereby forming a methanator effluent comprising hydrogen and methane;

introducing the methanator effluent together with nitrogen into an ammonia synthesis reactor to produce ammonia and a purge gas stream comprising hydrogen; and

sequestering the first amount of CO 2 and the second amount of CO 2 for sale or for other on-site or off-site uses.

15. A method of reducing carbon dioxide vented into the air during production of Fischer-Tropsch liquid hydrocarbons and ammonia, the method comprising:

introducing a carbonaceous raw material, water and oxygen into a synthesis gas generator under synthesis gas forming operating conditions to form a synthesis gas;

cooling the synthesis gas to condense and remove water;

removing sulfur compounds and a first amount of carbon dioxide from the synthesis gas using an acid gas removal system, thereby forming a cleaned synthesis gas;

separating the cleaned synthesis gas into a first portion of synthesis gas that is used for Fischer-Tropsch conversion and a second portion of synthesis gas that bypasses Fischer-Tropsch conversion;

introducing the first portion of the cleaned synthesis gas into a Fischer-Tropsch reactor and forming primarily aliphatic hydrocarbons and carbon dioxide;

separating Fischer-Tropsch liquid hydrocarbons from Fischer-Tropsch tail gas comprising unreacted carbon monoxide, carbon dioxide, and gaseous hydrocarbons;

combining the second portion of the synthesis gas with the Fischer-Tropsch tail gas to form a gas mixture;

compressing the gas mixture to an elevated pressure, thereby forming a compressed mixture;

introducing the compressed mixture together with steam into one or more shift reactors to convert a portion of the carbon monoxide and water to hydrogen and carbon dioxide;

removing a second amount of carbon dioxide from the shifted gases in an absorption unit, thereby forming reduced-CO 2 shifted gases;

introducing the reduced-CO 2 shifted gases into a hydrogen membrane separator to produce a stream of hydrogen-rich gases and a stream of hydrogen-lean gases;

compressing the hydrogen-rich gases to an elevated pressure;

introducing the compressed hydrogen-rich gases into a pressure swing adsorption unit to produce a stream of high purity hydrogen;

introducing at least a portion of the high-purity hydrogen together with nitrogen into a reactor to produce ammonia; and

sequestering the first amount of CO 2 and the second amount of CO 2 for sale or for other on-site or off-site uses.