Pressure overload safety precaution for ammonia absorption fridge

I acquired all the materials for the construction of a model of the solar ammonia absorption ice maker but we were concerned about the pressure - the system had to be fool proof i.e there needed to be some safety mechanism in case the system overheated and therefore over-pressurised.

Now we could not simply have a pressure release valve as releasing deadly ammonia into the atmosphere would be out of the question.

A brilliant solution to this problem was suggested by Ashley Pursglove: the ammonia released could be reacted with a solution of sulphuric acid to give ammonium sulphate, a relatively benign product which could safely be released into the atmosphere:

Now we just need to figure out the rate of this reaction to propose the equipment required to ensure all the ammonia is converted safely...

... now accoding to wikipedia I think we are supposed to use this equation to determine the rate of reaction:


Where:

r = rate of reaction
k = rate coefficient
A = concentration of reactant 1
B = concentration of reactant 2
m, n = stochiometric coefficients of balanced reaction or constants determined experimentally

Im sure this is a common reaction so these constants should be available somewhere but I havent found them yet. Anyone?

In any case I was thinking the apparatus for the reaction would look something like this:

We would probably want to include a expansion chamber immediately after the pressure release valve rather than blasting ammonia directly to the glassware at 200psi.