Co-production of hydrogen, carbon, and electricity with carbon dioxide capture

Patent metadata

Field	Value
Publication number	US-2023352712-A1
Application number	US-202217730942-A
Country	US
Kind code	A1
Filing date	Apr 27, 2022
Priority date	Apr 27, 2022
Publication date	Nov 2, 2023
Grant date	—

Abstract

A hydrocarbon feed stream is exposed to heat in an absence of oxygen (pyrolysis) to convert the hydrocarbon feed stream into a solids stream and a gas stream. The solids stream includes carbon. The gas stream includes hydrogen. The gas stream is separated into an exhaust gas stream and a first hydrogen stream. The first hydrogen stream includes at least a portion of the hydrogen from the gas stream. The carbon is separated from the solids stream to produce a carbon stream. Electrolysis is performed on a water stream to produce an oxygen stream and a second hydrogen stream. At least a portion of the oxygen of the oxygen stream and at least a portion of the carbon of the carbon stream are combined to generate power and a carbon dioxide stream. At least a portion of the generated power is used to perform the electrolysis on the water stream.

First claim

What is claimed is:

1 . A method comprising:
exposing a hydrocarbon feed stream comprising a hydrocarbon to heat in an absence of oxygen to convert the hydrocarbon feed stream into a solids stream and a gas stream, the solids stream comprising carbon, the gas stream comprising hydrogen; separating the gas stream into an exhaust gas stream and a first hydrogen stream comprising at least a portion of the hydrogen from the gas stream; separating the carbon from the solids stream to produce a carbon stream; performing electrolysis on a water stream comprising water to produce an oxygen stream and a second hydrogen stream, the oxygen stream comprising oxygen, the second hydrogen stream comprising hydrogen; and combining at least a portion of the oxygen of the oxygen stream and at least a portion of the carbon of the carbon stream to generate power and a carbon dioxide stream comprising carbon dioxide, wherein at least a portion of the generated power is used to perform electrolysis on the water stream.

2 . The method of claim 1 , wherein the hydrocarbon feed stream comprises a plurality of hydrocarbons selected from C1-C22 alkanes.

3 . The method of claim 2 , wherein the hydrocarbon feed stream comprises hydrogen.

4 . The method of claim 3 , wherein the oxygen and the carbon are combined by a direct carbon fuel cell comprising a solid oxide, and the oxygen and the carbon are combined by the direct carbon fuel cell at an operating temperature in a range of from about 800° C. (°C) to about 1000° C.

5 . The method of claim 4 , comprising transferring, by a first waste heat recovery heat exchanger, heat from the gas stream to a buffer fluid.

6 . The method of claim 5 , comprising transferring, by a second waste heat recovery heat exchanger, heat from the buffer fluid to the hydrocarbon feed stream prior to exposing the hydrocarbon feed stream to heat in the absence of oxygen.

7 . The method of claim 5 , comprising generating power by a Rankine cycle using the heat transferred from the gas stream to the buffer stream, wherein generating power by the Rankine cycle comprises:
transferring heat from the buffer fluid to a working fluid in a boiler to vaporize the working fluid into a vaporized working fluid; flowing and expanding the vaporized working fluid through a turbine to generate power; condensing the vaporized working fluid into a condensed working fluid; and circulating the condensed working fluid to the boiler.

8 . The method of claim 4 , comprising transferring, by a first waste heat recovery heat exchanger, heat from the carbon dioxide stream to a buffer fluid.

9 . The method of claim 8 , comprising transferring, by a second waste heat recovery heat exchanger, heat from the buffer fluid to the hydrocarbon feed stream prior to exposing the hydrocarbon feed stream to heat in the absence of oxygen.

10 . The method of claim 4 , comprising sequestering, within a subterranean formation, the carbon dioxide stream generated by the direct carbon fuel cell, such that the carbon dioxide stream is not released to the atmosphere.

11 . A system comprising:
a hydrocarbon feed stream comprising a hydrocarbon; a pyrolysis chamber configured to receive the hydrocarbon feed stream and expose the hydrocarbon feed stream to heat in an absence of oxygen to convert the hydrocarbon feed stream into a solids stream comprising carbon and a gas stream comprising hydrogen; a gas separation unit configured to receive the gas stream from the pyrolysis chamber and separate the hydrogen from the gas stream to produce an exhaust gas stream and a first hydrogen stream comprising at least a portion of the hydrogen from the gas stream; a carbon separation unit configured to receive the solids stream from the pyrolysis chamber and separate the carbon from the solids stream to produce a carbon stream; a water stream comprising water; an electrolysis unit configured to receive the water stream and electrical power, the electrolysis unit configured to use the electrical power to perform electrolysis on the water stream to produce an oxygen stream comprising oxygen and a second hydrogen stream comprising hydrogen; and a power generation unit configured to receive at least a portion of the oxygen stream from the electrolysis unit and at least a portion of the carbon stream from the carbon separation unit, the power generation unit comprising a direct carbon fuel cell configured to combine the oxygen from the portion of the oxygen stream and the carbon from the portion of the carbon stream to generate power and a carbon dioxide stream comprising carbon dioxide, wherein at least a portion of the power generated by the power generation unit is provided to the electrolysis unit to perform electrolysis on the water stream.

12 . The system of claim 11 , wherein the hydrocarbon feed stream comprises a plurality of hydrocarbons selected from C1-C22 alkanes.

13 . The system of claim 12 , wherein the hydrocarbon feed stream comprises hydrogen.

14 . The system of claim 13 , wherein the direct carbon fuel cell comprises a solid oxide electrolyte configured to operate at a temperature in a range of from about 800° C. (°C) to about 1000° C.

15 . The system of claim 14 , comprising a first waste heat recovery heat exchanger in fluid communication with the gas stream exiting the pyrolysis chamber and a buffer fluid, the first waste heat recovery heat exchanger configured to transfer heat from the gas stream to the buffer fluid.

16 . The system of claim 15 , comprising a second waste heat recovery heat exchanger in fluid communication with the hydrocarbon feed stream entering the pyrolysis chamber and the buffer fluid, the second waste heat recovery heat exchanger configured to transfer the heat from the buffer fluid to the hydrocarbon feed stream prior to the hydrocarbon feed stream entering the pyrolysis chamber.

17 . The system of claim 15 , comprising a Rankine cycle configured to generate power using the heat transferred from the gas stream to the buffer fluid, the Rankine cycle comprising:
a boiler configured to receive a working fluid and the buffer fluid, the boiler configured to transfer heat from the buffer fluid to the working fluid to vaporize the working fluid into a vaporized working fluid; a turbine configured to receive the vaporized working fluid and generate power as the vaporized working fluid flows and expands through the turbine; a condenser configured to receive and condense the vaporized working fluid into a condensed working fluid; and a pump configured to circulate the condensed working fluid to the boiler.

18 . The system of claim 14 , comprising a first waste heat recovery heat exchanger in fluid communication with the carbon dioxide stream exiting the power generation unit and a buffer fluid, the first waste heat recovery heat exchanger configured to transfer heat from the carbon dioxide stream to the buffer fluid.

19 . The system of claim 18 , comprising a second waste heat recovery heat exchanger in fluid communication with the hydrocarbon feed stream entering the pyrolysis chamber and the buffer fluid, the second waste heat recovery heat exchanger configured to transfer the heat from the buffer fluid to the hydrocarbon feed stream prior to the hydrocarbon feed stream entering the pyrolysis chamber.

20 . The system of claim 14 , wherein the pyrolysis chamber comprises a catalyst comprising at least one of activated carbon, carbon black, cobalt, iron, copper, or nickel.

Assignees

• Saudi Arabian Oil Co

Inventors

• Pham Thang
• Perez Omar David Hurtado
• Katikaneni Sai P

Classifications

• Y02E60/50

  Fuel cells · CPC title

• Y02E60/36

  Hydrogen production from non-carbon containing sources, e.g. by water electrolysis · CPC title

• Y02P20/129

  Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines · CPC title

• B01J2208/00106

  by indirect heat exchange · CPC title

• H01M2008/1293

  Fuel cells with solid oxide electrolytes · CPC title