Using a filter press to optimize your drying process
Mechanical dewatering separates liquids from solids and is often the first step in thermally processing a slurry to form a final dry powder. This article describes one type of mechanical dewatering equipment, the filter press. Sections cover filter press basics, filter press types, and automation options.
Many chemical, food, and pharmaceutical processes produce products in liquid-solid suspensions, or slurries, that must be thermally dried to attain the final dry powder product. Generally, whether the slurry is very dilute or very concentrated, using a mechanical dewatering device prior to introducing the slurry into a dryer will greatly improve dryer through-put and reduce the energy required to evaporate residual moisture. The dewatering step removes a large portion of the slurry's liquid phase, or mother liquor, resulting in a filter cake that ranges from soft and moist to firm and barely damp, depending on the equipment you use and your application's requirements. Selecting a dewatering device that produces the highest possible filter cake solids [the firmest, driest filter cake] your dryer can handle will maximize your drying system's throughput.