Manufacturing
Process
Various methods for Reclamation or re-refining of used oils are
in practice and mainly they are classified into two main groups
- Physical Method
- Physio-chemical
Physical Method
Mechanical Filtration
Mechanical Filtration is widely used method of re-cycling. Here
contaminants are separated mechanically or by absorption or
adsorption by passing through materials of controlled porosity. The
principles of various types of filters are described below
- Area or edge type strainer embody a purely mechanical process
of forcing oil by pressure through a straining device which
prevents the passage of solid contaminants above a certain size.
The filter elements are usually made with different porosity.
Porous metallic or non-metallic filters are made in either
cylindrical or disc form by compacting or sintering metal,
ceramics, or glass powder of graded fineness. Other strainers
may be paper, fabric or other materials.
- Depth Filter in turn, may be divided into two general classes
- Absorbent - A mechanical action that remove fine contaminants
such as insoluble oxidised material and coarser particles from
the oil.
- Adsorbent - a process in which one substance attracts another
and retains the material to be removed from the oil on the
surface and throughout the filter medium
- Gravity Filter is actually a low head pressure filter,
depending for its action on slight difference in head between
the dirty and clean oil level.
Vacuums Dehydration It is a well-known oil-recycling method.
Water and oil, for all practical purpose, are immiscible liquids. If
not agitated, water introduced into lubricating oil separates
readily by gravity. However, any kind of agitation can break up the
body of water into small droplets, which become dispersed in the oil
and are then not readily separated by gravity. The more intense and
persistent the agitation, the finer these droplets will split into
particles.
In the vacuum dehydrating-cum-filtering unit, the oil to be treated
is heated to comparatively lower temperature in vacuum, thus
obviating the necessity of using high temperatures with possible
resulting in oxidation of the oil. It employs fuller's earth to
remove suspended solids and oil oxidation products. Vacuum
vaporisation removes moisture, diluent fuel, low molecular weight
organic acids and other impurities, which have a boiling point lower
than that of the oil. Before the oil passes to the clean oil storage
tank, small filter press and then a secondary filter using a fabric
as a filtering medium filter it. The product of this purification
process is straight mineral oil, which can be blended with
additives, as desired.
Centrifugal Separation
It is efficiently used in some commercial oil purifying equipment
to separate solids and free water from the oil. The method involves
whirling the dirty oil to separate it into layer of insoluble
contaminants, water and clean oil. Water and some of solids will be
expelled near the periphery of the bowl, and clean oil through or
near the center. Two types of centrifugal separators are much in
use. One is known as disc type centrifuge. It can be used as a
purifier to eliminate the solids only. In the second, known as a
tubular type centrifuge, the oil enters near the bottom of the
vertical bowl and is expelled at the top.
Both types of centrifugal purifiers can be used either alone or in
combination with pressure filter.
Magnetic Separation
Several types of magnetic filters are used principally for the
removable of ferrous metal contaminants from low viscosity oils and
water-soluble oil coolants. There are two typical devices much in
use viz:
- First type has no moving parts and consists of a stack of
soft steel grids placed between and magnetised by two powerful
permanent magnets. This enuregrid stack is enclosed in a
cylindrical case through which the liquids flow. This filter is
not of the self-cleaning type and must be taken out of use for
cleaning at varying intervals depending upon the service.
- Second type known as rotating-drum design of magnetic filter
consists of a rotating drum from which the ferrous particles are
scrapped off and discharged.
Physio-Chemical Method
These Methods have been developed for those oils, which are heavily
contaminated and re-refining is not possible only by physical
methods.
Re-refining of the used oils has been practiced over the past fifty
years. Among the first commercial approached for this, the ACID/CLAY
refining had been widely adopted in the past.
With the ever-increasing awareness towards the cleaner environment,
following new ECO friendly process producing higher yields of
re-refining oils have been developed which totally eliminates ACID
SLUDGE.
- PROP-Philips Recovery Oil Process
- Resource Technology Process
- K.T.I. Process
- RRL Jorhat Process
- BORC Treatment
Prop-Philips Recovery Oil Process:
PROP is advanced oil Re-refining Technology Developed by Philips
Petroleum Company (USA), that restores waste lubricating oils to
their original quality.
PROP does this without environmentally questionable use of ACID &
or Solvents, & without vacuum distillation.
Pre-treatment of waste oil feed stock is not required.
The process combines unique & proprietary chemical
demetalization followed with hydro treating to produce high yield of
base oil.
Chemical
Industry
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