Fuel Cell Humidification Using Nafion® Moisture Exchange Devices: Fuel Cell Humidification Using Nafion® Moisture Exchange Devices


Slide2: Company History Founder worked at DuPont when Nafion® was developed as an ionomer for electrolysis membranes for production of chlorine and alkali DuPont elected not to pursue development of business exploiting water permeation properties Founder left DuPont, started Perma Pure (PPI) in 1972 to produce Nafion dryers and humidifiers Subsequently purchased exclusive license to produce Nafion tubing from DuPont


Slide3: Company History (continued) Founder patented dryer and humidifier designs, built business supplying to OEM customers Markets are instrumentation for medical, process control, environmental monitoring and laboratory Medical market is largest segment; PPI produces ca. 1,000,000 dryers per year for breath analysis In 1992, founder retired, sold business to Halma plc; present management in place since then.


Slide4: Company History (continued) Halma plc is 106 years old, owns 57 companies; very successful with high capital reserves After purchase, PPI expanded into process applications, including fuel cells PPI business is global, with 51% export sales PPI supplied humidifiers for fuel cells for years; PPI sponsored winning fuel cell-powered car in 1999 Tour de Sol, using PPI humidifier


Gas Dryer and Humidification Technology: Gas Dryer and Humidification Technology


Nafion® Chemical Structure: [ (CF2 CF2 )m CF CF2 ] n O CF2 CF CF3 O CF2 CF2 WHEN: m = 5 to 13.5 n = ca 1,000 z = 1,2,3... x = 1 to 13 Z SO3H [H2O]X . Nafion® Chemical Structure


Slide7: Selectivity Permeation selectivity is based on chemical reactivity, not size Only compounds that chemically associate with sulfonic acid permeate Bases associate with sulfonic acid and permeate through membrane wall Very few bases are gases at typical operating temperatures, so very few compounds permeate


Slide8: Why use Nafion as the moisture exchange membrane in fuel cell humidifiers? Nafion transfers moisture quickly Water transfers through Nafion as a first order kinetic reaction Water transport is driven by partial vapor pressure differential Small device provides high performance Nafion transfers water selectively Water associates readily with sulfonic acid groups and permeates through the membrane wall Permeation selectivity is based on chemical reactivity with sulfonic acid, not size No crossover of any other components besides water Nafion protects expensive fuel cell components Impurities that would poison fuel cell membranes will be trapped in humidifier Humidifier acts as final scrubber before fuel cell stack


Perma Pure’s Nafion-based humidifiers for fuel cells: Perma Pure’s Nafion-based humidifiers for fuel cells Used to humidify hydrogen or air Humidifiers available to handle gas flow from under 1 lpm up to 4,000 lpm Recent advances including development of a molded housing have reduced costs by more than 50% in some devices


Perma Pure’s humidifiers are passive devices: Perma Pure’s humidifiers are passive devices No moving parts No parts to break, wear out, maintain, or control No energy required to operate Will not be a drain on your system No controls needed Self limiting operation means water transfer will never exceed saturation


Slide11: Heat and Moisture Exchange Diagram Perma Pure’ humidifiers consist of a bundle of Nafion tubes, arranged much as a shell and tube heat exchanger. The inlet gases to be humidified typically flow through the bundle of tubes, and the cathode exhaust or heated de-ionized water surrounds the tubes, providing the source of heat and moisture.


Gas to Gas Humidifiers Cathode exhaust stream flows in shell, Inlet gas flows through tubing: Gas to Gas Humidifiers Cathode exhaust stream flows in shell, Inlet gas flows through tubing Most efficient method of humidification available Can achieve high degree of water transfer (over 85% of water content) No energy required Humidifiers available to handle wide range of flows (< 1 lpm up to 4,000 lpm), temperatures (up to 130 C) and pressures (up to 4 bar) New low cost model available with molded shell and fittings


Performance of gas to gas humidifiers: Performance of gas to gas humidifiers


Gas to gas humidifiers offer low pressure drop: Gas to gas humidifiers offer low pressure drop


Partial product line of gas to gas humidifiersNOTE: FC300 style now with low cost molded components: Partial product line of gas to gas humidifiers NOTE: FC300 style now with low cost molded components


Liquid to Gas Humidifiers Water flows in shell, gas flows through tubing: Liquid to Gas Humidifiers Water flows in shell, gas flows through tubing Variable performance can be achieved by regulating temperature of water surrounding Nafion tubing Typically used for test bench applications where variable humidity is required, or to humidify hydrogen Can achieve high degree of humidity (up to 99% RH) Water requirements Heated De-ionized Circulated Cooling water can be used if quality is appropriate


FC 300 gas to gas humidifierNEW: Molded ABS shell and fittings for low cost: FC 300 gas to gas humidifier NEW: Molded ABS shell and fittings for low cost


Slide18: FC 400 gas to gas humidifier


Slide19: FC 400 gas to gas humidifier


Humidifier Development: Humidifier Development Development projects underway: Performance improvements of membrane Optimize tube geometry Packaging developments to meet customer needs Custom shapes and configurations to meet packaging requirements Molded housings to reduce costs in commercialized projects Investigation of new materials and manufacturing methods Improve temperature and pressure tolerance Reduce Costs


Outlook: Outlook Commercialized in several major projects and working with most of the leaders in the industry, Perma Pure is meeting today’s fuel cell humidification requirements. With over 30 years of experience designing and building moisture exchange devices, we believe we will be able to provide the cost effective humidification solutions required by the industry tomorrow.