BulkDryRape - Interactive computer-based tool

Abstract

Full scale tests were undertaken in the grain store at the Food and Environment Research Agency to provide data for validation of BulkDryRape, an interactive computer-based tool for oilseed rape drying. This data was compared with a more flexible simulation using the same mathematical calculations as BulkDryRape.

Bins 3 to 6 were each loaded with approximately 15 t of oilseed rape (OSR). Each bin was fitted with a 5.5 kW fan, which was used to dry the OSR at an average flow of 112 m3/h/t. Bins 5 and 6 had average initial moisture contents of 12.9% and 13.3% respectively and were dried successfully using continuous ventilation over 21 days.

Bins 3 and 4 had average initial moisture contents of 12.0% and 11.7% respectively and were dried intermittently over 37 days so that mould was visible before drying was complete. Samples were taken at least twice weekly for assessment of moisture content, the presence of mites and moulds.

Mould was visible by microscope in all samples taken 31 days after harvest from the surface and at depth 0.5 m from bins 3 and 4. No mould was visible in the previous sample set taken two days earlier. No mould was observed in any of the samples from bins 5 and 6 and no mites were observed in any of the samples from any of the bins. The time taken for the appearance of visible mould was in line with results from the literature based on small scale tests on OSR.

Table 1 shows the storage and field mould counts for samples taken immediately after loading the bins and after the drying front had reached the surface of the OSR.

Table 1. Storage and field moulds present at the start and end of drying

Overall, the measured drying behaviour and risk of spoilage were well predicted in both continuous and intermittent drying, giving confidence in the BulkDryRape software.