6.2 Design Equations for Batch Filter Cycles

As described in Section 6.1, the cycle for a batch filter can comprise one or more cake formation phases followed by any sequential combination of consolidation, displacement washing and gas deliquoring phases. While a complex batch cycle may involve the list of operations shown in Table 6.2, a more typical cycle can be represented by

where the subscripts f, c, d and w are used to respectively indicate values during the filtration, consolidation, deliquoring and washing phases of a cycle of total duration t _T; the term t _dn denotes filter downtime, for cake discharge and cloth cleaning, which is largely ignored for the purpose of calculations (although Section 6.2.5 shows how it can be incorporated in determinations of optimum filtration time). Each phase of the cycle can theoretically continue until the desired cake properties have been achieved or the economics of the operation dictate that a particular phase must end. More phases can be accommodated in a cycle by simple additions to equation (6.1).