The present invention relates to a granular-material dehumidification plant including at least one silo or hopper arranged to receive granular material to be dehumidified at the top thereof and provided with a controlled lower delivering mouth, at least one feeding duct designed to be dipped in the granular material contained in each hopper to supply hot and dry processing air thereto, and at least one exhaust duct for humid processing air; at least two molecular sieve towers arranged alternatively to supply hot and dry processing air to the at least one hopper, each tower delimiting therein a space for housing molecular sieves and a chamber for housing heating means, the space and the chamber being in fluid communication with one another at one end thereof, while being in fluid communication at the other end thereof, with a respective air inlet/outlet duct.