Environmental Engineering Reference
In-Depth Information
5
Some local governments and even countries have adopted laws that limit
plasticsuseinspecificapplications.However,itisalsonotuncommonfor
the regulations to be so lax that it is environmentally counterproductive
but might be profitable.
6
LPG is a by-product of the petroleum refining process, and NGLs are
removed from natural gas before it is used as fuel gas in transmission
lines. Coal can also be used to make plastics; the first nylon made was
based on coal feedstock.
7
According to 2006 data by the US Energy Information Administration,
4.6% of petroleum resources were used by plastics industry.
8
Percentage of the thermal energy from burning fuel converted into
mechanical work in an internal combustion engine is around 26%.
However, the actual mechanical efficiency is lower as some of the energy
is wasted in overcoming frictional forces.
9
This is why theoretical calculations based on thermodynamic
considerations are not that useful in environmental assessments. All
processes are inefficient and produce waste, and the energy costs depend
on the type of energy used.
10
By comparison, the energy in crude oil is about 47 GJ/ton.
11
The value for glass is from Joshi et al. (2004).
Fuel Combustion.” (International Energy Agency, Paris, France).
13
The value is for plastic resin manufacturing operation only. For
extraction of petroleum, the IR ~ 80%.
14
All varieties of “cling” films do not contain plasticizers; some are based
on polyethylene.
15
Good plasticizer molecules have a balance between polar and nonpolar
groups, the latter allowing self-association or “pooling” within the
polymer matrix.
16
There are a few examples of plasticizers such as epoxy plasticizers in PVC
that are covalently linked to the polymer chain.
