A kinetic model of fumigant sorption by grain using batch experimental data

Abstract

The model describes the transient changes of fumigant concentrations in both the intergranular air and grain. It provides the capacity to predict fumigant concentrations throughout grain stacks for a wide range of scenarios of industrial importance.

Modelling the kinetics of ethyl formate sorption by wheat using batch experiments

“…A brief review of modelling of the kinetics of fumigant sorption by grain can be found elsewhere 2. Fig.…”

“…Fig. 1 illustrates the mass transfer model proposed in this work, which is an extension of that developed previously 2. Reversible fumigant transport between the air and the adsorption surface within the grain kernel pores is accounted for by a simple linear mass transfer coefficient.…”

“…Batch adsorption of fumigants by grain usually exhibits two phases 1, 2. Firstly, there is an initial rapid uptake of fumigant, illustrating the dominance of a smaller mass transfer resistance.…”

“…This is followed by a slower sorption phase that can extend for many weeks. Most fumigants are observed to react with grain constituents,1, 2 yet desorption studies indicate that the reaction kinetics is slow, as significant amounts of unreacted fumigant exist after several weeks 1, 2. Sorption of ethyl formate also exhibits these characteristics 3–7…”

“…Most fumigant sorption studies have involved dilute concentrations that correspond to relative saturations of < 3%,1, 2, 28 and full adsorption isotherms have not been defined accordingly. Moisture adsorption isotherms for wheat involving the full range of relative saturations have been determined and exhibit ‘type‐II’ curves 18, 29, 30.…”