Page 141 - Analysis, Synthesis and Design of Chemical Processes, Third Edition

Suggest some ideas for the zebra mussel problem in Example 4.1.

One possible idea is to invent a chemical or determine whether there is a chemical that can kill existing
infestations. It would be nice if this were combined with a chemical that can prevent the infestations. If
either of these methods were to be used, some type of delivery system would be needed. Another
possibility is to place some type of filter at the water intake to keep the zebra mussels out of the water
intake. Because zebra mussels are attracted to the warmer water near power plants and water treatment
facilities, another possibility is to find a way to cool this water. There are undoubtedly other
possibilities. Can you think of any?

Example 4.6

Suggest some ideas for the chlorine problem in Example 4.2.

An alternative disinfectant to chlorine would be one possibility. A chemical would need to be developed
that has similar disinfectant properties to chlorine, but without the smell and irritation. This would
address those problems but not the problem of the time and effort needed to add disinfectant. Another
possibility is some type of automatic dispenser for chlorine or a replacement disinfectant, so that a
disinfectant reservoir would only have to be changed periodically and would not require daily attention.
Another possibility is a device that makes chlorine from a less toxic chemical, in situ, somewhere in the
filtration system. This would keep chlorine out of the pool, confining it to the region where water is
circulated through the filter. There are undoubtedly other possibilities. Can you think of any?

Example 4.7

Suggest some ideas for a power source for laptop computers, as discussed in Example 4.4.

One possibility is to develop better batteries. This is currently being done. Early laptop computers used
NiCd batteries. The next generation was Ni-metal-hydride batteries, and the current generation is Li-ion
batteries. There will probably be another generation forthcoming. Another possibility is to develop fuel
cells that can be used to power a laptop computer. There may be other possibilities. Can you think of any?

4.4 Selection

Once a sufficient number of ideas has been generated, it is necessary to screen the ideas and select a few
for more detailed investigation. Scientific principles can be applied. If it is thermodynamically
impossible to manufacture an alternative, that idea can be eliminated. If it is determined that the kinetics
of a desired reaction are unfavorable, that idea might be eliminated or downgraded, although this might
stimulate development of a new catalyst to improve selectivity. If it is possible to determine at this stage
that an alternative will be far too expensive relative to another idea, that idea might be eliminated or
downgraded. However, when in doubt, it is probably best not to reject any idea too soon.