Predicting CIPC vapour and particle distribution in potato stores

This project aimed to assess the concept of sprout control using CIPC vapour and/or small particles of CIPC in stores, so as to improve the uniformity of CIPC treatments and residue distribution. The approach would only be effective if sufficient CIPC could be released into a store and air flow within the store could be managed to encourage effective dispersion of the released CIPC. Therefore, the work involved generation of the data required to create models to predict CIPC distributions in store.

• Preliminary experiments in which CIPC vapour was introduced into a chamber from which air samples were drawn to determine the size distributions and airborne concentrations of particles suggested that it would be possible to treat potato stores with vapour as a means of distributing CIPC more evenly within a store
•  A potential method of generating CIPC vapour by heating solid material to a controlled temperature in a glass container was shown to be feasible at an experimental scale
•  Models were developed to predict the application of vapour CIPC for sprout control in commercial potato stores. These included models for CIPC evaporation into air, transportation by air movements and absorption by potatoes
•  There was no clear evidence, from available test results, to show a dependence of the absorption coefficients on potato variety, but the absorption coefficients at 10^oC were lower than that at 4^o C
• The models were validated against experimental results. The models gave predicted distribution patterns that showed the same trends as in the measured data
• Predictions were made for CIPC vapour applications in a 12-tonne experimental store using a hot source (i.e. CIPC vapour generated at high temperatures). The predictions were higher than the recoreded measurements. It was proposed that this was because the absorption of vapour CIPC by store walls and floor and by potato boxes had been under-estimated in the models

 The last use of CIPC as a potato sprout supressant was in 2020.