A Life Cycle Assessment of the PureCell Stationary Fuel Cell System ...

PureCell System Maintenance
Several maintenance activities are needed to keep the fuel cell functioning properly over
its entire lifetime. Maintenance activities included in the inventory table are the
replacement of activated carbon for water treatment and the hexavalent chromium
emissions caused by cleaning the condenser. Other maintenance activities include
replacing the Rohm and Haas resin for water treatment, a quarterly replacement of air
filters and other replacements which are done on a case-by-case basis (e.g., blowers and
fans). These are however not included in the LCA because no data on these activities are
available.
Materials Amount Unit Waste treatment
Activated carbon PureCell
system 1852.5 lb
Total 1852.5 lb
Waste to treatment
inorganic general 1852.5 lb Landfill Compostables
chromium compounds 570 kg LT waste to chemical landfill
chromium compounds 570 kg Waste to chemical landfill
Table 4-26: PureCell system maintenance inventory data
The activated carbon for water treatment is replaced three times a year. Initially, 60 lb
activated carbon is used in the PureCell system. The maintenance data are based on a
PureCell system lifetime of 85,000 hrs. In the definition of the PureCell system
lifetime 8000 hrs is regarded as one year (vs. 8760 actual hours); this means that the
lifetime in years is 10 5/8 year. The total amount of activated carbon needed for
maintenance then becomes: 120 lb + (9*180) lb + 5 *180lb
= 1852. 5lb
.
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The activated carbon waste is indicated as ‘inorganic general’ and is assumed to end up
in landfills.
The condenser is cleaned annually resulting in waste water containing hexavalent
chromium. Per annual cleaning 15 to 30 gallons of waste water are produced with a
hexavalent chromium concentration below 5%. For the calculations it is assumed that 15
gallons with a 5% hexavalent chromium concentration are produced annually.
15 Gallons is equal to 57 liter or 57 kg. With 10 annual cleanings, this results in 570 kg
waste water to treatment, containing 28.5 kg Cr (VI)
. This is a conservative estimate: it
is expected that most of this is Cr (III). Although the waste is described as ‘chromium
compounds’, the SimaPro software only recognizes the amount of waste and the waste
treatment it is sent to. This means that it is not possible in SimaPro to include the exact
amount of hexavalent chromium in the model. The 570 kg waste is assumed to go to
landfill; it appears twice in the inventory table because both the short-term and long-term
effects are taken into account.
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