Offshore Technical Services has together with Pieralisi designed a mobile Decanter package in a 20 ft offshore container. A Hercules 470/4 is installed with hydraulic drive. The package includes a strainer to prevent large particles to enter the system. A mono feed pump, flow meter, and conveyer to transport the solids into mud skips. Effluent tank with discharge pump for the water phase. The Decanter is able to remove large amount of solids from wastewater and drilling mud. Fluid containing up to 60% solid are easily handled through the system. The unit could also be used to reduce weight on drilling mud. By changing weir plates dewatering volume is easily changed. Such operation takes normally 20-25 minutes.
The specially designed Decanter could also be converted to a 3 phase Decanter by installing a special design flange and separating oil, water and solids. The operation to dismantle the 2-phase flange and assemble the 3-phase flange takes about 6 hours.
Theoretical capacity as a 2-phase unit is 55 m³/h.
The unit has been tested out onshore on waste fluid from different offshore field with very good result. Laboratories result confirm that sludge which contains more than 75% solids are reduced down to less than 3% on the effluent side. Typical results on solid side are in weight %: Water 4% Oil 12,8% and solids 83,2%. When processing slop water all the solids are removed from the water.
Test with 3-phase flange on typical slop water from offshore indicate that the operator has to test fluid first. This is to verify the total amount of oil that is present in the slop water. Operator is then able to assemble the correct weir plates for the oil and water level inside the decanter. To prevent traces of oil in the water phase the operator needs to set the water level in such matter inside the decanter that some water goes into the oil phase.
The unit is certified for offshore use.