Transcript Hardware Description and Operating Characteristics

Hardware Description and Operating Characteristics of the
Plug Power GenSys 5C 5KW Fuel Cell System
Terrence L. Chambers, Ph.D., P.E.
University of Louisiana at Lafayette
Used with permission of Plug Power, Inc.
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Major Fuel Cell System Components
Air
Power
Generation
Module
Fuel
Processor
Natural
Gas or
Propane
Hydrogen
Power
Conditioner
DC Power
AC Power
Heat and
Water
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Fuel Processor
 Convert Energy from Natural Gas (CH4) into
Hydrogen rich Reformate (Fuel)
Main Reactor
 Ensure that the fuel supply for the fuel cell has a
low CO concentration
CO Scrubber
 Reclaim waste fuel in the form of heat, and control
exhaust emissions
Anode Tailgas Oxidizer
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Main Reactor
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Main Reactor Produces Most of the Hydrogen
Chemical Reactions in the Main Reactor
— 98% Catalytic Partial Oxidation
– CH4 + ½ O2  2H2 + CO
— 2% Steam Reformation
– CH4 + H2O  3H2 + CO
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CO Scrubber
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CO is an Anode Catalyst Poison
Chemical Reactions in CO Scrubber
— Section 1: Reduces CO and produces some H2
– CO + H2O  H2 + CO2
— Section 2: Preferential Oxidation of CO
– CO + ½ O2  CO2
If too much O2 is added in Section 2, then you burn up your
fuel
— H2 + ½ O2  H2O
After CO Scrubber, CO concentration < 50 ppm
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Anode Tailgas Oxidizer (ATO)
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Oxidizes any leftover Hydrogen, Natural Gas, or CO in
anode tailgas coming from FC stack
Recovers heat energy
Makes exhaust gasses safe to release into atmosphere
Chemical reactions in ATO
— H2 + ½ O2  H2O
— CH4 + 2O2  CO2 + 2H20
— CO + ½ O2  CO2
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Power Generation Module
Power Generation Module - uses hydrogen in reformate
to produce electricity (DC voltage)
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Power Generation Module
• Fuel & Air Delivery
• Cooling
• Waste Heat Capture
• Integrated Controls
– Fuel Processor
– Stack/Balance of Plant
– Inverter/Grid
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Power Generation Module
The Fuel Cell Process
Every fuel cell has
One positive electrode - cathode
One negative electrode - anode
An electrolyte - carries charged particles
A catalyst - speeds up the reactions
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Power Generation Module
NET REACTION
2H2 + O2 => 2 H2O
Anode Reaction
2H2=>4H+ + 4e-
Cathode Reaction
02+4H++4e-=>2H2O
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Power Generation Module
Engine of the Fuel Cell: the MEA
Primary Function: Site of electrochemistry and power generation
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Membrane Electrode Assembly - 5 layer
— Gas Diffusion Layer bonded to an ionomeric membrane
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Gas Diffusion Layer : GDL
— Provides diffusion of fuel and oxidant gases into catalyst layer
Catalyst may be deposited onto the membrane or the GDL
— Electrode layer may be a catalyst/Teflon or catalyst/ionomer formulation
Plates distribute reactants uniformly over GDL
Plate
Cathode: Air
Gas Diffusion Layer
Catalyst
Membrane
Gas Diffusion Layer
Anode: Hydrogen Rich
Plate
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Power Generation Module
Five Layer Membrane
Electrode Assembly
Power Conditioning Module
Functions
•Convert Stack DC power or Battery DC power to quality AC
residential power
•Provide Auxiliary DC power using stack DC power.
•Maintain batteries using stack DC power
•Provide isolation between the stack and the AC connection
•Provide to the Control Module (SARC) all electrical statistics
including stack voltage and current.
•Provide the ground connection for the entire Fuel Cell System (DC
negative and chassis)
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Power Conditioning Module
Fuel Cell
Auxiliaries
Inverter
J3
Utility
DC Bus
AC Line
Filter
Battery
FC
Contactor
Fuel Cell
Stack
Stack
Converter
Generator
Disconnect
Switch
House Service Panel
120/240 V
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Power Conditioning Module
Functions
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Fuel Cell Contactor: The fuel cell contactor electrically isolates or connects the
stack to the Stack Converter. It is controlled by a digital line from the SARC, as well
as via RS485 commands from the SARC. Both control methods must be configured
to enable the contactor to close in order to draw current from the stack.
Stack Converter. The Stack converter controls all power flow from the stack. It
provides all the power needed for battery charging, auxiliaries and inverter stage
input. This stage must be enabled in order to draw current from the stack.
Batteries. The batteries provide reserve power during start-up and shutdown,
when the stack is unavailable.
Power Inverter. The inverter stage transforms the DC power of the system (battery
or stack) to AC power. It controls in both current control mode (grid parallel) and
voltage control (stand alone).
AC line filter. This filter reduces EMI emissions from the power electronics.
Generator Disconnect Switch. The generator disconnect switch acts to isolate or
connect the grid to the power electronics output (the corcom filter), and the load
connection.
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GenSysTM 5C Fuel Cell System
Product Characteristics
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Size: 74” x 32” x 68 1/4” (LxWxH)
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Power Rating: 5kWe (9kWth)
continuous
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Power: 2.5 - 5kWe (3-9kWth)
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Voltage: 240/120VAC @ 60Hz
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Power Quality: IEEE 519
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Emissions:
— NOx < 1ppm
— SOx < 1ppm
— Noise < 65dBa @ 1 meter
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Certifications:
— CSA International
— UL
— FCC Class B
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GenSysTM 5C Fuel Cell System
CHP mode:
 Reclaims the waste heat generated by the fuel cell and offers
it to the customer
 Can supplement and in some cases replace the heat source
for many existing customer systems such as baseboard heat,
space heating and potable water
 Results in a cheaper, more efficient overall system.
Standby capability:
 Normal operation - the fuel cell provides base electrical
service to the facility and the grid supplements peaks and
surges. Unused electricity will flow back to the grid.
 Power outage - the fuel cell continues to provide electricity to
critical loads (and acts as a back-up generator
 Fuel cell shuts down - electricity to the facility will be
provided uninterrupted from the electric grid.
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Technical Challenges
• Fuel processing, stacks, system integration, size and weight,
response times, …...
• Fuel supply and infra structure
- Natural gas: variation in composition
- Liquid-based fuels (methanol): lacking infra structure
- Hydrogen: 20 - 30 years away
• Low cost components
- Catalysts: precious metal supply, recovery techniques
- Membrane
- Power electronics/inverters
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