OK.... given that pressure has little effect on "reversing a
reversible reaction" at the 400 C range, is it not likely that higher
pressures could act as the equivalent to a "negative activation energy" to
prevent the reaction from occurring in the first place?
As a "Laymen Example".... a little spray of water will
extinguish the match, prventing the firecracker from "reacting." However, if
the firecracker has "reacted", then no amount of water spray will reverse the
reaction..
It would thus seem obvious that pressure applied
before an irreversable gassifying reaction occurred would have a
reasonable expectation of yielding good results, by
potentially preventing the undesired reaction.
Does that make sense?
Kindest regards,
Kevin Chisholm
Dear
Paul: I agree with Tom's comments. Most of my work has emphasized
somewhat lower temperatures, where thermochemical equilibrium is not often
achieved. It is usually instructive to compare observed results with
thermochemical equilibrium predictions. As one approaches equilibrium,
dramatic changes in the product slate become less likely. But in my
experience (at lower temperatures without catalysts) the equilibrium
calculation is only a rough guide, that can offer insights in the absence of
experiments (i.e. its cheaper to run STANJAN than to do an experiment).
For example, detailed thermochemical equilibrium calculations predict a
negligible influence of pressure (above 1 atm) on charcoal yields from
cellulose at 400 C. As my work has shown, this prediction could be quite
misleading. Best regards, Michael.
