Page History

Current Efficiency Factor

The efficiency factor previously being used in the flocculation model for plant design had been the best estimate of a completely an unknown parameter, so ; it was not necessarily an accurate measure representation of flocculation efficiency in the plant. When the parameters of the existing design parameters plant were used to create a model design in MathCAD, the observed flocculation the location of the maximum floc size as predicted by the model did not match that predicted by the model, and it was the observed location. We therefore determined that the efficiency factor had been incorrectly estimated.  , and that models being created with the design program were not practical. In order to determine a more realistic model for the new plant design, we set out to determine the actual efficiency factor.

Procedure

Flocculation We observed flocculation in the demo plant was observed in order to determine at what point in the length of the flocculator the flocs reached a maximum size before beginning to break up. The These flocs in the current plant were also measured in order to be able to more accurately represent in the flocculation model the maximum floc size currently being achieved that it is possible to achieve in the flocculation modelplant. Using this the location of the largest flocs as an estimate of the optimum plant length, we set the maximum floc size to the size of the measured flocs and changed the value of the efficiency factor in the flocculation model until the design length of the plant model created by the Demo Plant MathCAD design Design program was consistent with the observed results.demo plant design program was used with the previously estimated efficiency, occurrence of maximum floc size.

Results

The maximum flocs were observed at a distance of 28 cm from the flocculator inlet. After that point in the plant, they ceased to get any bigger, and eventually began to break up from too much shear. The size of the largest flocs was about 0.7 mm, so that value was set as the maximum floc size in the flocculation model. When various efficiencies were tried in the model, the plant design program returned a design length of approximately 28 cm for a value of 0.2, and so we have determined that the flocculation efficiency is equal to this value.