Page 139 - Materials Chemistry, Second Edition

L1644_C03.fm Page 113 Tuesday, October 21, 2003 3:11 PM

level. Explain briefly the main faults of eco-indicator 95 and the advan-
tages introduced by eco-indicator 99.
8. Summarize the weighting methods proposed for use in LCIA and briefly
describe their advantages and disadvantages.
9. How many times should the glass bottle be recycled to generate the same
amount of equivalent CO as the plastic bottle? Answer: 7 times.
2
10. Compare plastic sheets to paper from cellulose pulp.
According to NASA, the ozone’s layer hole above Antarctica has been in-
6
creasing. If, on September 19, 1998, it was measured 27.2 × 10 km 2
and, 2 years later, on September 3, this surface had increased to 28.3 ×
2
6
10 km , determine what would have a worse effect on the ozone’s lay-
er: using a 5-g paper pulp sheet or a 5-g low density polyethylene
(LDPE) sheet. The comparison must be based on the measurement of
the ozone depletion potential (ODP) expressed as kilograms of CFC-11
equivalent. The needed environmental loads (ELs), in this case emis-
sions of chlorfluorinated compounds (CFCs) to the air for paper and
polyethylene production and the corresponding impact factors, are giv-
en in the following table:
EL Unit Paper (EL/kg) LDPE (EL/kg)
Halon 1301 kg 7.15 × 10 –8 6.85 × 10 –7
CFC-11 kg 2.37 × 10 –9 4.06 × 10 –9
CFC-114 kg 6.24 × 10 –8 1.07 × 10 –7
CFC-12 kg 5.08 × 10 –10 8.73 × 10 –10
CFC-13 kg 3.19 × 10 –10 5.48 × 10 –10
HCFC-22 kg 5.66 × 10 –10 9.60 × 10 –10
Impact factors:
Compound Unit Factor
Halon-1301 kg 1.6 × 10 1
CFC-11 kg 1
CFC-114 kg 8.0 × 10 –1
CFC-12 kg 1
CFC-13 kg 1
HCFC-22 kg 5.5 × 10 –2
11. Compare the use of two different plastics: PP and PVC. A company
endeavors to compare the environmental impact due to the industrial use
of two polymers: polypropylene (PP) and polyvinyl chloride (PVC) as
raw material for manufacturing piping. It considers it necessary to take
into account two variables: the raw material and its transport. Two alter-
natives are supposed:
1. Buying PP piping from a distributor who receives the product by
train from a factory 1000 km away and uses a van to deliver the
product to a consumer who is 200 km from the distributor
2. Buying PVC tubes from a distributor who acquires the product by
a 16-t truck from a factory 700 km away and uses a van to deliver
the product to a consumer who is 50 km from the distributor
To compare the environmental behavior of each product, the company
makes use of three parameters: kilograms of consumed oil, GWP

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