OIL RECOVERY FROM TANK BOTTOM SLUDGE

OFT's proprietary Bio-Mechanical Combination Process is developed for recovery of useful oil from the tank bottom sludge.

In this process, the tank bottom sludge is mixed with an aqueous phase solvent known as SOLPAR.*The mixture is then pumped into a blending tank. In the blending tank, the
dissolved sludge is blended with cutter stock such as crude oil in the ratio of 1:0.5 to 1:1.

The blended sludge is then pumped to Gyro separators. The Gyro Separators have a unique circular motion vibration screens arranged in two different layers. Each layer has a
certain opening to allow passage of liquid. The screens act as first stage solid filters. At this stage, the solids in the range of 40 microns and above are removed, and then
transported to a solids collection bin.

The solids are then treated with SOLPAR solution at high concentration to permanently destroy any residual hydrocarbons making the solids readily disposable. After this first stage filtration stage where more than 80% of the solids are removed, the liquids are pumped into a Tricanter Centrifuge. The centrifuge then separates the three phases of water, oil and solids. Solids once again are treated with SOLPAR solution and collected into the solids disposal bin.

The recovered water is then passed through a Coalescer where the recoverable oil is separated from the water and water having hydrocarbon content of less than 100 ppm is allowed to pass through for re-use in the operation.

Oil recovered is clean and has less than 1% solids and thus pumped to the client storage facilities. Normally, SOLPAR solution separates out of the oil phase due to its inherent oleophobic property. However, sometimes, it may require the assistance of the heat energy to break the emulsion, particularly in case the sludge is of napthenic nature and has a tendency to form ready emulsions. In such an event , the recovered oil is passed through a heat exchanger where the temperature of the fluid is raised to app. 60 deg C., to allow for the clean separation of the oil and water phases. This operation is normally undertaken before
the centrifuge stage.

The Recovered oil meets with the BS&W norms and delivered to the receiving facility. The solids are collected and after testing for oil content, they are moved to the disposal area. However, in case they do not meet the disposal norms, then they are re-introduced into the process system for further stripping of oil, till the solids are left with the oil content that meets the approval standards.

Salient Features of this Advanced Sludge Processing System

* The process used is eco-friendly and the biosurfactants used are non-toxic, and biodegradable.
* The hydrocarbon recovery from the process is the highest in the industry and we have achieved a recovery factor of more than 98% from the existing oil content in
the sludge.
* The Process is low on power needs and high on efficiency due to minimum number of moving parts. The downtime due to mechanical repairs is very low and non-existent.
* The recovered oil meets the highest standards set by the refineries.
* The residual solids and water are treated as well.The water outflow contains hardly any hydrocarbons and safe for disposal.