Flow Distribution Parameters in Relation to Flow Resistance in an Upflow Anaerobic Sludge Blanket Reactor System

The use of flow resistance in the distribution of flows is well known in traditional hydraulics. To evenly distributed flows, flow resistance forms the basis of flow distribution in pipes connected in parallel. Flow distribution in different zones of upflow anaerobic sludge blanket (UASB) reactors is well documented in existing literature, and so far modeling of flow distribution parameters, i.e., the fraction of inflow entering into the bed, the fraction of flow bypassing over the bed and entering into the blanket, and the fraction of inflow to the bed entering into the blanket, has remained empirical in nature. The role of flow resistance in the distribution of flows in UASB reactor systems is still unexplained. In this study, some of the available data on flow distribution parameters are analyzed to assess if there is any correlation between these parameters and flow resistance. It is found that with an increase in flow resistance in the UASB reactor system, the magnitude of short-circuiting flows at the reactor bed increases. Also, the flow distribution at the blanket and settler levels of UASB reactor systems is related to parameters influencing flow resistance. Some of the functional forms derived in this study are expected to form the basis for representing flow distribution in the simulation studies of UASB reactor performance.