Research and optimisation of the quantitative and qualitative characteristics of grain shipload lots in grain terminals

The structure of loading different crops onto vessels at the company Ukrelevatorprom’s grain terminal has been considered. The total grain shipped in 2012–2015 was comprised of 33.7–41.5% of maize, 19.7– 32.2% of wheat, 14.4–26.0% of rapeseed, 6.7–14.2% of barley, and 5.4– 11.0% of soya beans. When forming a 35,000-tonne grain shipload, grain lots stored in silos are sometimes of lower quality than contracts require: the protein and gluten contents can be inappropriate, or there can be smut grains or those damaged by sunn pests. The accepted technology of grain shipload formation does not guarantee that the grain quality will be uniform throughout the whole period of loading a vessel, especially in the beginning. In the first 1,000 tonnes of a grain shipload formed, the weight content of wet gluten was found to be 22.6% instead of 23%, the Falling Number was 145–180 s instead of 230s, and the content of smut grains was not the tolerable 5%, but 6.95–7.8%. The subsequent 2,000–3,000 tonnes of wheat, too, had the Falling Number lower than the contract prescribed (142–215 s), and only further on, its value achieved the required range 295–356 s. In the wheat sample formed from 5,000 tonnes, only the test values of the Falling Number (176s) and the content of smut grains (5.1%) were different from what the contract required. The calculated arithmetic means of the quality parameters of the 5,000-tonne wheat samples formed were practically the same as those determined experimentally, except for the values of the Falling Number and the smut grain content. The values of the coefficient of variation obtained showed that the grain lot was of non-uniform quality: it varied in such parameters as the foreign material (20.82–50.93%), sunn pest-damaged grains (7.41–25.76%), Falling Number (8.76–36.36%), and smut grain content (35.88–78.34%). Application of linear programming methods to optimise the shipload composition has allowed all the quality parameters to meet the contract requirements. Loading grain from all silos simultaneously, with the optimum flow ratio, will result in its even distribution in a shipload, and the grain lot will be of higher quality by all the parameters the contract specifies.