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

Patent metadata

Field	Value
Publication number	US-2016359182-A1
Application number	US-201514732032-A
Country	US
Kind code	A1
Filing date	Jun 5, 2015
Priority date	Jun 5, 2015
Publication date	Dec 8, 2016
Grant date	—

Abstract

A high efficiency fuel cell system adapted to receive flue gas from a flue gas generating device and to capture carbon dioxide from the flue gas, the 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, and a separation assembly configured to receive carbon dioxide-containing exhaust and to separate carbon dioxide from the carbon dioxide-containing exhaust, wherein the carbon dioxide-containing exhaust is one of anode exhaust output from the bottoming anode portion and a gas derived from the anode exhaust output from the bottoming anode portion, and wherein at least 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.

First claim

1 . A high efficiency fuel cell system adapted to receive flue gas from a flue gas generating device and to capture carbon dioxide from the flue gas, the high efficiency fuel cell system comprising:
a topping fuel cell assembly comprising two or more topping fuel cell modules, each topping fuel cell module 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; and a separation assembly configured to receive carbon dioxide-containing exhaust and to separate carbon dioxide from the carbon dioxide-containing exhaust, wherein the carbon dioxide-containing exhaust is one of anode exhaust output from the bottoming anode portion and a gas derived from the anode exhaust output from the bottoming anode portion, wherein at least 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, wherein the topping fuel cell assembly has a greater number of fuel cells than the bottoming fuel cell assembly so that the topping fuel cell assembly utilizes more fuel than the bottoming fuel cell assembly, and wherein the system is configured such that anode exhaust from each of the topping anode portions of the topping fuel cell modules is combined after exiting the respective topping anode portions, and the combined anode exhaust is received by the bottoming anode portion.

2 . The high efficiency fuel cell system in accordance with claim 1 , wherein the topping cathode portion and the bottoming cathode portion each receive a portion of the flue gas output from the flue gas generating device in parallel.

3 . 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.

4 . The high efficiency fuel cell system in accordance with claim 3 , 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.

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

6 . The high efficiency fuel cell system in accordance with claim 1 , wherein:
the carbon dioxide-containing exhaust is anode exhaust output from the bottoming anode portion, the separation assembly outputs separated carbon dioxide and separately outputs separated anode exhaust with a reduced amount of carbon dioxide, and the separated anode exhaust is recycled to the topping anode portion for use as fuel.

7 . The high efficiency fuel cell system in accordance with claim 6 , further comprising a conduit and a flow control member for bleeding off a small amount of the separated anode exhaust to remove inert gases prior to recycling the remaining separated anode exhaust to the topping anode portion.

8 . The high efficiency fuel cell system in accordance with claim 1 , wherein:
the system further comprises an oxidizer assembly for oxidizing anode exhaust output from the bottoming anode portion with one or more of air and oxygen to generate the carbon dioxide-containing exhaust and to generate waste heat for heating the flue gas before the flue gas is provided to the at least one of the topping and bottoming cathode portions, and the separation assembly outputs separated carbon dioxide and separately outputs a separated gas with a reduced amount of carbon dioxide.

9 . The high efficiency fuel cell system in accordance with claim 1 , wherein the separation assembly comprises:
a condenser for cooling the carbon dioxide-containing exhaust to separate water from the carbon dioxide-containing exhaust and to output a water separated carbon dioxide containing exhaust, and a carbon dioxide separator for separating carbon dioxide from the water separated carbon dioxide-containing exhaust to output a separated gas with a reduced carbon dioxide content and to separately output carbon dioxide suitable for one or more of storage and external use.

10 . The high efficiency fuel cell system in accordance with claim 9 , wherein the carbon dioxide separator separates the carbon dioxide using one or more of compression and cryogenic cooling to generate liquid carbon dioxide, solvent washing, and a membrane process.

11 . The high efficiency fuel cell system in accordance with claim 1 , further comprising a controller for controlling the flow rate of the flue gas to the one or more of the topping cathode portion and 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 CO2 utilization of 50% or greater.

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

13 . 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.

14 . The high efficiency fuel cell system in accordance with claim 1 ,
wherein the bottoming anode portion further receives supplemental fuel, and the high efficiency fuel cell system further comprises a controller for controlling the amount of supplemental fuel conveyed to the bottoming anode portion, wherein the controller controls the amount of current generated in the bottoming fuel cell assembly by controlling the amount of supplemental fuel conveyed to the bottoming anode portion.

15 . The high efficiency fuel cell system in accordance with claim 1 , further comprising a controller, wherein the controller controls one or more of:
(a) the amount of current generated in the topping and bottoming fuel cell assemblies so 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; (b) the amount of current generated in the bottoming fuel cell assembly based on electricity needs so that the amount of current generated in the bottoming fuel cell assembly is increased when the electricity need increases; (c) the flow of the flue gas to be conveyed to the topping fuel cell assembly and to the bottoming fuel cell assembly in parallel or in series; (d) the flow rate of flue gas to the topping fuel cell assembly and to the bottoming fuel cell assembly to achieve a predetermined overall CO2 utilization; (e) the pr

Assignees

• Fuelcell Energy Inc

Inventors

• Farooque Mohammad
• Juhas Carla
• Venkataraman Ramakrishnan

Classifications

• H01M8/249

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

• H01M2008/147

  Fuel cells with molten carbonates · CPC title

• H01M8/0491

  of fuel cell stacks · CPC title

• H01M8/04089

  of gaseous reactants · CPC title

• H01M8/04753

  of fuel cell reactants · CPC title