STUDIO DI UN IMPIANTO E PROVE SPERIMENTALI DI STRIPPAGGIO DELL'ANIDRIDE SOLFOROSA DAI MOSTI D'UVA

For technological and economical reasons, in the grape juices production the long time storage of the must is made by addition of sulphur dioxide (up to 2000 mg/l). For legal reason, on preparing and packing the juice, the stripping of the sulphur dioxide is necessary (legal limit is 10 mg/l). The available stripping plants date back to a patent of 1955 and they have serious troubles to obtain such a deep stripping with economical productivity. Therefore a mathematical model was given to predict the sulphur dioxide stripping by the steam generated from the must; in fact it is forbidden to utilise steam of the boiler. This allowed a right design and the construction of a pilot plant. Experimental results, on different musts, indicated that the new pilot plant is able to stripping with a residual sulphur dioxide under the legal limit. A residual concentration range of 5-9 mg/l was obtained. Also, a high productivity (6000 kg/h) was obtained against about 1000 of old plants.