Introduction
VMAT is designed to handle motor oil, hydraulic oil or similar oil products with viscosity @40°C between 70-80cSt. Feed shall be visually inspected to prevent undesirable substances entering the system, such as water, solvent, glue, paint, large amount of solids, or sludge etc.
Feed is first settled at the sedimentation tank to separate free water and large solids. Then it is pumped through heating and vacuum dewatering system. The temperature will be maintained at around 90°C and water content should be less than 1%. Small amount of water and volatile organic may be extracted, which could be removed by condensation or activated carbon. Dewatered feed is maintained at 80-85°C passing through a protective filter before entering vibrating membrane.
Vibrating membrane filters the feed into permeate and concentrate. Permeate is clear brown color and is immediately suitable for low grade lubricant or further processing, with viscosity @40°C between 40-45cSt. Concentrate is viscous dark lubricant together with viscosity improver and residual additives, with viscosity @40°C between 130-140cSt. To achieve higher recovery rate, the concentrate is fed to the feed tank through a centrifuge that also takes gummy tar out of the feed. Since the permeate does not expose to high temperature, it is not cracked and does not carry bad, mercaptan odour.
The process can maintain steady filtration up to 2 weeks depending on feed conditions and feed supply. Upon switching to other feed source, operator will flush the filter pack with permeate for half an hour. The operator may also wash the filter pack with Dunwell supplied cleaner in case flux goes down.
VMAT implies minimal secondary pollution, low temperature/energy cost, small footprint, purely physical separation and continuous production.