Firstly, polysaccharide (sucrose, starch) is dissolved to 58% with purified water in a hydrolysis tank, the PH value is adjusted to 4.5, and is decomposed into glucose and fructose under the action of hydrogen ions. Next, the mixed sugar solution passes through an ion
exchange column, and glucose solution and fructose solution are respectively obtained through different absorbability of the ion sugar solution. Hydrogenation under the condition of nickel as catalyst to produce mannitol dilute solution. Mannitol dilute solution can be
further concentrated by a plate evaporation and concentration device or a tubular evaporation and concentration device, because a large amount of steam needs to be consumed during concentration, multi-effect evaporation or heat pump can be used to reduce energy consumption. The mannitol solution with increased concentration enters a crystallizer, cools
and crystallizes, and is separated under the action of a centrifuge to obtain crude mannitol crystals. In order to further obtain industrial mannitol crystals, the crude mannitol crystals are dissolved in water, filtered, re-crystallized in a crystallizer, centrifugally separated and screened to finally obtain industrial mannitol with qualified quality.
