Fuel Specification for fuel cells

Size: px

Start display at page:

Download "Fuel Specification for fuel cells"

Lindsay Carr
6 years ago
Views:

1 Fuel Specification for fuel cells EU workshop on Regulations, codes and standards for H 2 /FC technologies February 25, 2005 Paul van den Oosterkamp Frank de Bruijn ECN-Fuel Cell Technology

2 Outline Fuel Cell Applications and Fuels Fuel diversity and Fuel Cells Production of Fuels for Fuel Cells Centralised Decentralised Impurities for PEMFC Impurities in Fuel Processing Conclusions

3 Fuel Cell Applications and Fuels Hydrogen Methanol Natural Gas Propane Natural Gas Stationary Power (< 250 kw) Portable Power (1-200 W) Hydrogen Gasoline Micro CHP (1-5 kw) Hydrogen Gasoline Marine Hydrogen oil Gasoline Ships APU and propulsion ( kw) Transport ( kw) City Transport (2-5 kw) Kerosine Airplane APU ( kw)

4 Centralised production of Hydrogen Natural Gas, LPG Established tolerance levels Aromatics Organic Sulphur Inorganic Sulphur Fuel specifications and reformate/hydrogen production Hydrogen storage or Fuel Processor Established tolerance levels H 2 S,CO,CO 2,NH 3,H 2 S hydrogen air - Fuel Cell Stack + Established tolerance levels CO Decentralised production of hydrogen reformate!natural gas!lpg!gasoline!diesel!kerosine!biofuels Compressor air CO 2 NH 3 H 2 S SO 2 etc Fuel and air specification needed

5 Fuel diversity and fuel cells Natural Gas LPG Middle Distillates Liquid Bio-fuels Gas-to- Liquids Synthesis Gas Solar Wind Hydrogen PEMFC PAFC SOFC MCFC methane Biomass

6 Centralised Hydrogen production Process steam Desulphurizer H.T. shift Stack Reformer (Radiant section) PSA purge gas drum PSA System Feed Heat recovery (Convection section) Fuel Heat recovery and cooling Hydrogen product 99,999 % H 2

7 Decentralised Hydrogen production NG LPG Sulphur Removal CPO CPO ATR ATR SR SR HT HT shift shift LT LT shift shift PROX PROX fuel fuel cell cell Combined Heat & Power (1-5 kw) exhaust anode anode exhaust exhaust utilisation utilisation

8 Influence of impurities PEMFC Reformer - Primary reformer (SR/ATR/CPO) - Shift (HT & LT) - Pref.Oxidation (Prox)

9 Influence of CO in reformate PEMFC Mean cell potential [V] Source : ECN H2 43%H2 / 41% N2 / 16%CO2,, + 10 ppm CO,, + 10 ppm CO + 1.5% air Current density [A/cm²] Conditions: C 1 atm l=1.25/2

10 1 Influence of H 2 S in hydrogen for PEMFC Cell Voltage (V) ppm H2S 0.2 ppm H2S Source : ECN Time (hrs)

11 Influence of CO 2 in reformate PEMFC Reverse watergas shift 0.5 V [ma/cm 2 ] CO 2 + H 2 CO g,ads + H 2 O - 30% 0.35 mg/cm2 Pt 0.35 mg/cm2 PtRu - 12% 20% CO 2 is equivalent to 10 ppm CO Reverse WGS is hindered on PtRu CO 2 concentration (%) Source : ECN

12 Influence of NH 3 concentration in reformate PEMFC Cell voltage (V) Operating time (hours) Reversible degradation Stationary performance of a cell fed with a mixture of 75% H 2 / 25% N 2 and 5 ppm NH 3 in the interval from 210 hours to 475 hours. Current density is 500 ma/cm 2. Source : ECN

Influence of NH 3 in cathode air PEMFC Current Density @ 0.5 V [A/cm 2 ] 1 0.9 0.8 0.7 0.

13 Influence of NH 3 in cathode air PEMFC Current 0.5 V [A/cm 2 ] ppm NH Anode = cathode = 0.4 mg.cm -2 Pt Time [hours] Source : ECN

14 Influence of SO 2 in cathode air PEMFC Current 0.5 V [A/cm 2 ] ppm SO Source : ECN Time [hours]

15 Example Sulphur influence on CPO reforming (typical conditions) 100 normailsed conversion ppmws 10 ppmws 120 ppmws Same trend is visible for Shift Source : ECN time (hr)

16 Impact on lack of fuel specifications for fuel cells ; example : Sulphur DESIRE (WEU project). Initial fuel specification: NATO-F76 (0.2 wt.% S) R&D spent on sulphur removal: app. 200 keuro By lack of succes in S removal from F-76, City diesel (10 ppm S) is now used. Celina (EU project) Fuel specification:3000 ppm (kerosene) R&D to be spent on fuel characterisation and sulphur removal: app. 250 keuro.

17 Impact on lack of fuel specifications for fuel cells (2) : example : Sulphur Optimisation of centralised production of low sulphur fuels in refinery vs.decentralised S-removal (which needs a lot of R&D) Source : Fuel Cell Energy Fuels for fuel cell systems Source : TU-Delft

18 Fuel specifications/conclusions Should not only focus on hydrogen Should not only focus on fuel cell, also on reformer components Quick decisions on future fuel specifications can save a lot of R&D efforts and money. Especially for liquid fuels with S presence. Specifications need to be a compromise between impact on cost for fuel cell,costs for hydrogen production and costs for infrastructure. It makes no sense to have a fuel quality for the fuel cell which is much higher than the air quality.

Influence of Bio-Syngas Contaminants on SOFC

Influence of Bio-Syngas Contaminants on SOFC BioCellus & Green Fuel Cell Bert Rietveld, Nico Dekker, Jan Pieter Ouweltjes www.ecn.nl Introduction A Solid Oxide Fuel Cell converts H 2 directly in electricity