The kinetics of methyl bromide hydrate formation

The rate of formation of methyl bromide hydrate in a continuous stirred tank reactor has been measured under conditions in which the ΔT driving force, the degree of agitation, the salt concentration in the aqueous phase, the volume fraction of liquid methyl bromide present and the fraction of solids present in the slurry were all varied. As long as the agitation intensity is over 0.01 hp/gal and there is at least 3 volume % liquid methyl bromide present in the reactor, the hydrate formation rate appears to be controlled mainly by the kinetics of the interfacial reaction to form crystals. Under these conditions only 10% to 25% of the total driving force is used to boil the refrigerant while the remainder is consumed by the interfacial reaction. This is in contrast to the butane freezing process where nearly all the ΔT is consumed by boiling of the refrigerant. With a slurry solids concentration of 15% and a ΔT of 2.5°C specific reaction rates are over 60 lbs of water solidified per hour per ft3 of slurry.