Equilibrium Moisture Content and Drying Analysis of Biosolids

Thermo chemical conversion of biosolids to syngas or to fuels often includes a thermal drying step as the moisture content of the biosolids must be around 30%. Equilibrium moisture content (EMC) data of biosolids are required for good design and control of the drying process. The EMC data for Municipal sludge were measured in the relative humidity range of 11-85% at the temperatures from 30^oC to 60^oC. The data were fitted to several well known models, including one model accounting for mixing and swelling contributions to water activity in the biosolids .Using this new model, we characterized both bonded and non bonded water. This information is used in the design of a fluidized bed dryer for handling and processing biosolids including for a preliminary cost analysis.