This case is a xylitol evaporation system using KDP's plate evaporator. The xylitol evaporation system is divided into three stages. The first stage is preheating, using condensed water or secondary steam to preheat the low-temperature xylitol solution to near the boiling point, reducing the energy consumption of the subsequent evaporation process. In the second stage of evaporation and concentration, the KDP plate heat exchanger serves as the main heater, providing heat through steam or heat medium to evaporate the water in the xylitol solution. In the third stage, heat recovery recovers the heat of the secondary steam through a multi-effect evaporation or MVR (mechanical vapor recompression) system to reduce fresh steam consumption. Through the reasonable selection and material matching of KDP, the plate heat exchanger can significantly improve the energy efficiency and product purity of xylitol production.