Functioning and process engineering design - Silos

Silos are predominantly constructed as elevated, flat-bottomed, silos with vehicle access underneath, each with an integral displacement cone and a base aeration system as the method of the extraction. Their process engineering design is described with the aid of a specific design variant of this type of silo. Among other things, the function of the displacement cone in the generation of a suitable bulk material flow profile, the potential for bridging in the outer silo space, the requirements for dimensioning the base aeration system and the control engineering aspects are analysed and supported with examples. The structural variant investigated is then compared with two alternative design variants of displacement cone silos. Their differences and the resulting consequences are discussed. The possibility of constructing aerated silos without displacement cones is described for examples of two configurations, of which one is suitable for fairly small storage volumes and the other for extremely large storage volumes. The article ends with advice on the configuration of multi-compartment silos in a cylindrical structure. The investigation makes it clear that there has to be an adequate understanding of the bulk material to be handled as the basis for responsible silo design.