High-efficiency fuel cell system with carbon dioxide capture assembly and method

Patent metadata

Field	Value
Publication number	US-10170782-B2
Application number	US-201615298316-A
Country	US
Kind code	B2
Filing date	Oct 20, 2016
Priority date	Jun 5, 2015
Publication date	Jan 1, 2019
Grant date	Jan 1, 2019

Abstract

A high efficiency fuel cell system includes a topping fuel cell assembly that includes a topping cathode portion and a topping anode portion, as well as a bottoming fuel cell assembly that includes a bottoming cathode portion and a bottoming anode portion. The assembly also includes a flue gas generating device configured to provide flue gas to the topping cathode portion and/or the bottoming cathode portion, and an oxidizer assembly configured to (i) oxidize anode exhaust output from the bottoming anode portion with air and/or oxygen to generate carbon dioxide-containing exhaust and (ii) generate waste heat for heating the flue gas before the flue gas is provided to the topping cathode portion and/or the bottoming cathode portion. A separation assembly is configured to receive the carbon dioxide-containing exhaust from the oxidizer assembly and to separate carbon dioxide from the carbon dioxide-containing exhaust.

First claim

What is claimed is:

1. A high efficiency fuel cell system comprising:
a topping fuel cell assembly comprising a topping cathode portion and a topping anode portion;
a bottoming fuel cell assembly comprising a bottoming cathode portion and a bottoming anode portion, wherein the bottoming anode portion receives anode exhaust output from the topping anode portion;
a flue gas generating device configured to provide a portion of the flue gas to each of the topping cathode portion and the bottoming cathode portion in parallel;
an oxidizer assembly configured to (i) oxidize anode exhaust output from the bottoming anode portion with air and/or oxygen to generate carbon dioxide-containing exhaust and (ii) generate waste heat for heating the flue gas before the flue gas is provided to the topping cathode portion and/or the bottoming cathode portion; and
a separation assembly configured to receive the carbon dioxide-containing exhaust from the oxidizer assembly and to separate carbon dioxide from the carbon dioxide-containing exhaust.

2. The high efficiency fuel cell system of claim 1 , further comprising a controller configured to control a temperature in the oxidizer assembly by controlling an amount of the air and/or oxygen provided to the oxidizer assembly.

3. The high efficiency fuel cell system of claim 1 , wherein:
the separation assembly comprises a condenser, and a carbon dioxide separator;
the condenser is configured to condense out water and output water separated carbon dioxide-containing exhaust to the carbon dioxide separator, and
the carbon dioxide separator is configured to separate carbon dioxide from the water separated carbon dioxide-containing exhaust.

4. The high efficiency fuel cell system in accordance with claim 3 , wherein the carbon dioxide separator is configured to separate the carbon dioxide using compression and cryogenic cooling to generate liquid carbon dioxide.

5. The high efficiency fuel cell system in accordance with claim 3 , wherein the carbon dioxide separator is configured to separate the carbon dioxide using solvent washing.

6. The high efficiency fuel cell system in accordance with claim 3 , wherein the carbon dioxide separator is configured to separate the carbon dioxide using a membrane process.

7. The high efficiency fuel cell system in accordance with claim 1 , wherein one of the topping cathode portion and the bottoming cathode portion receives at least a portion of the flue gas output from the flue gas generating device and generates cathode exhaust, and the other one of the topping cathode portion and the bottoming cathode portion receives the cathode exhaust generated by the one of the topping cathode portion and the bottoming cathode portion.

8. The high efficiency fuel cell system in accordance with claim 7 , wherein the topping cathode portion receives at least a portion of the flue gas output from the flue gas generating device and generates cathode exhaust, and the bottoming cathode portion receives the cathode exhaust generated by the topping cathode portion.

9. The high efficiency fuel cell system in accordance with claim 1 , wherein the topping cathode portion and the bottoming cathode portion are configured to selectively receive the flue gas in parallel or in series, and wherein the system further comprises a controller configured to selectively control a flow of the flue gas to the topping cathode portion and the bottoming cathode portion to be in parallel or in series.

10. The high efficiency fuel cell system in accordance with claim 1 , further comprising a controller configured to a the flow rate of the flue gas to the topping cathode portion and/or the bottoming cathode portion to support a fuel cell cathode side electrochemical reaction in each of the topping and bottoming fuel cell assemblies and to achieve an overall carbon dioxide utilization of 50% or greater.

11. The high efficiency fuel cell system in accordance with claim 1 , further comprising a controller configured to control flow rates of flue gas and fuel through the topping fuel cell assembly and bottoming fuel cell assembly such that pressures between the topping anode portion and the topping cathode portion are balanced and pressures between the bottoming anode portion and the bottoming cathode portion are balanced.

12. The high efficiency fuel cell system in accordance with claim 1 , wherein overall fuel utilization by the high efficiency fuel cell system is 80% or greater.

13. The high efficiency fuel cell system in accordance with claim 1 , further comprising:
a supplemental fuel source configured to supply supplemental fuel to the bottoming anode portion; and
a controller configured to control an amount of current generated in the bottoming fuel cell assembly by controlling an amount of supplemental fuel conveyed to the bottoming anode portion.

14. The high efficiency fuel cell system in accordance with claim 1 , further comprising a controller configured to control an amount of current generated in the topping and bottoming fuel cell assemblies such that, as operating time of the high efficiency fuel cell system increases, the amount of current generated by the topping fuel cell assemblies decreases and the amount of current generated by the bottoming fuel cell assemblies increases.

15. The high efficiency fuel cell system in accordance with claim 1 , further comprising a controller configured to control a flow rate of flue gas to the topping fuel cell assembly and to the bottoming fuel cell assembly to achieve a predetermined overall carbon dioxide utilization.

16. The high efficiency fuel cell system in accordance with claim 1 , further comprising a controller configured to control an amount of supplemental air supplied to the topping cathode portion and/or the bottoming cathode portion so as to control the temperature and concentration of carbon dioxide and oxygen in a cathode inlet gas conveyed to the topping cathode portion and/or the bottoming cathode portion.

17. A method of operating a high efficiency fuel cell system, the method comprising:
providing a topping fuel cell assembly comprising a topping cathode portion and a topping anode portion;
providing a bottoming fuel cell assembly comprising a bottoming cathode portion and a bottoming anode portion,
providing a portion of the flue gas to each of the topping cathode portion and the bottoming cathode portion in parallel;
receiving, at the bottoming anode portion, anode exhaust output from the topping anode portion;
oxidizing, with an oxidizer assembly, anode exhaust output from the bottoming anode portion with air and/or oxygen to generate carbon dioxide-containing exhaust;
heating the flue gas before the flue gas is provided to the topping cathode portion and/or the bottoming cathode portion using waste heat generated during said oxidizing; and
receiving, at a separation assembly, the carbon dioxide-containing exhaust from the oxidizer assembly and separating carbon dioxide from the carbon dioxide-containing exhaust.

18. A high efficiency fuel cell system comprising:
a topping fuel cell assembly comprising a topping cathode portion and a topping anode portion;
a bottoming fuel cell assembly comprising a bottoming cathode portion and a bottoming anode portion, wherein the bottoming anode portion receives anode exhaust output from the topping anode portion;
a flue gas generating device configured to provide flue gas to the topping cathode portion and/or the bottoming cathode portion;
an oxidizer assembly configured to (i) oxidize anode exhaust output from the b

Assignees

• Fuelcell Energy Inc

Inventors

• Farooque Mohammad
• Juhas Carla
• Venkataraman Ramakrishnan

Classifications

• H01M2008/147

  Fuel cells with molten carbonates · CPC title

• H01M2008/1293

  Fuel cells with solid oxide electrolytes · CPC title

• H01M8/249

  comprising two or more groupings of fuel cells, e.g. modular assemblies · CPC title

• H01M8/0668 Primary

  Removal of carbon monoxide or carbon dioxide · CPC title

• H01M8/0612

  from carbon-containing material · CPC title