Study On Alteration Of Fluidized Bed Dryer For ABS Plant

The mostly resolved alteration of dryer is insufficient cushioning capacity of hopper in ABS. If powder lot is easily blocked up, oxidation by contact of air and powder lot can be reduced. The alteration improves product appearance quality and is in favor of safety in production. But in ABS productive process, there is no precedent used by N2 circle drying system, and many technical problems have not been resolved and carried out. The ABS plant had started up since 1997, owing to the deficient design, instability of drying system is continuous, the plant was unable to achieve the design load, and the system was always in the in-and-out condition. Because of product inhomogeneous appearance, users' reflection is not good. So price of products is 300RMB/ton lower than other products at home and abroad. Aiming at this condition, at the beginning of onset by versatile comparisons technician in branch factory hold up N2 circle drying system, in which heated N2 instead of heated air and N2 is closed loop. The system uses spray tower removing moisture carried secretly in N2. Extraction of heat quantity is two-stage refrigeration, the initial chilling uses circulating water, the secondary chilling uses shallow cold water. Pressure in the circle drying system is split control, which can supply and release N2 in time. Draft blower is changed to high-power to increase exit pressure. By high-power draft blower the drag of cooling tower is overcome in order to guarantee amount of wind in the drying system. On the distribution plate under fluidized bed dryer large granule discharge pipes are installed, which can achieve the aim of mostly resolved alteration. Using N2 circle drying system instead of air drying can prevent powder lot contacting air. The resolved can avoid not only system deflagrating but also ABS products changing color by oxidation. Effects of alteration guarantee products uniform color and make safety.