Scale-up of steam pressure filtration

The characteristic of steam pressure filtration is the distinctive and even dewatering front. First, the interest has been focused on the main dewatering mechanism of steam pressure filtration. The question was whether the even and sharply distinctive dewatering front remains stable when the filtration face is scaled up by the factor 50. The experimental studies were carried through on a 3.75 m(2) disc filter which was modified for steam pressure filtration. A temperature sensor was installed in the rotating disc of the filter. The temperature at the filter cloth, opposite to the steam atmosphere is measured. The steam break through which determines the end of the mechanical displacement of the filtrate can be detected. The duration until the steam breaks through the filter cake in pilot scale is compared to the duration measured in lab scale. A simple calculation is presented which computes approximately the steam break through. The calculated steam breakthrough is also compared to the experimental data. The degree of moisture reached using the pilot scale steam filter is compared to conventional pressure filtration on the same pilot filter and data measured in lab scale. (C) 1999 Elsevier Science S.A. All rights reserved.