Continuous purification of motor oils using a three-phase separator

Patent metadata

Field	Value
Publication number	US-2016304805-A1
Application number	US-201415102130-A
Country	US
Kind code	A1
Filing date	Dec 4, 2014
Priority date	Dec 10, 2013
Publication date	Oct 20, 2016
Grant date	—

Abstract

A method for continuous purification of motor lubricant oil includes circulating lubricant oil between a motor lubricant oil tank and a motor; transporting contaminated lubricant oil from the motor lubricant oil tank in a cleaning loop. The transport in the cleaning loop includes adding at least one liquid separation aid to contaminated lubricant oil; supplying contaminated lubricant oil to a three-phase centrifugal separator; continuously separating contaminants from the lubricant oil in the separator and continuously discharging a first liquid phase including purified lubricant oil from a liquid light phase outlet of the separator, continuously discharging a second liquid phase including solid contaminants from a liquid heavy phase outlet of the separator and continuously discharging a sludge phase from a sludge outlet by the aid of a conveyor screw of the three-phase separator. The method further includes transporting the first liquid phase including purified oil back to the lubricant oil tank. The present invention further provides a system for carrying out the method.

First claim

1 . A method for continuous purification of motor lubricant oil comprising the steps of:
circulating lubricant oil between a motor lubricant oil tank and a motor; transporting contaminated lubricant oil from said motor lubricant oil tank in a cleaning loop, said transport in said cleaning loop comprising the steps of:
adding at least one liquid separation aid to contaminated lubricant oil;
supplying contaminated lubricant oil with said liquid separation aid to a three-phase centrifugal separator;
continuously separating contaminants from said lubricant oil in the separator and continuously discharging a first liquid phase comprising purified lubricant oil from a liquid light phase outlet of the separator, continuously discharging a second liquid phase comprising solid contaminants from a liquid heavy phase outlet of the separator and continuously discharging a sludge phase from a sludge outlet by the aid of a conveyor screw of the three-phase separator; and
transporting said first liquid phase comprising purified oil back to the lubricant oil tank.

2 . The method according to claim 1 , wherein at least 50% of the solid contaminants are discharged in the second liquid phase from the liquid heavy phase outlet of the separator.

3 . The method according to claim 2 , wherein the at least one liquid separation aid comprises polyhydroxy alkoxylate with a density of 1.0-1.1 g/cm 3 at 40° C.

4 . The method according to claim 1 , wherein the at least one liquid separation aid is labelled.

5 . The method according to claim 1 , wherein the step of adding at least one liquid separation aid to contaminated lubricant oil further comprises mixing the contaminated lubricant oil and the liquid separation aid before supply to the three-phase centrifugal separator.

6 . The method according to claim 1 , wherein the flow rate in the in the circulation of lubricant oil between the motor lubricant oil tank and the motor is more than 50 times higher than the flow rate in the cleaning loop.

7 . The method according to claim 1 , wherein the temperature of the contaminated lubricant oil is at least 70° C. during separation in the three-phase separator.

8 . The method according to claim 1 , wherein the step of transporting contaminated lubricant oil from the motor lubricant oil tank in the cleaning loop comprises withdrawing contaminated lubricant oil from a first position in the lubricant oil tank and further wherein the step of circulating lubricant oil between the motor lubricant oil tank and the motor comprises withdrawing lubricant oil from a second position, other than the first position, in the lubricant oil tank.

9 . The method according to claim 8 , wherein the first liquid phase comprising purified oil is transported back to the lubricant oil tank near said second position.

10 . The method according to claim 1 , wherein the method is continuously carried out during running of the motor to which the lubricant oil tank is connected to.

11 . The method according to claim 1 , further comprising measuring the concentration of at least one additive that neutralizes acid contaminants within the motor lubricant oil, and if the concentration is below a predetermined value, then adding at least one additive that neutralizes acid contaminants to the motor lubricant oil.

12 . A system for continuous purification of motor lubricant oil, said system comprising:
a lubricant oil tank, a motor and means for circulating lubricant oil between said oil tank and motor; a three-phase centrifugal separator for separating contaminants from lubricant oil, said separator comprising a rotor enclosing a separation space with a stack of separating discs, a separator inlet for contaminated lubricant oil extending into said separation space, a liquid light phase outlet for purified lubricant oil extending from said separation space, a liquid heavy phase outlet extending from said separation space, and a conveyor screw enclosed in the rotor and arranged for conveying a sludge phase towards and out of a sludge outlet of the separator; means for transporting contaminated lubricant oil from the lubricant oil tank to the separator inlet and means for transporting purified oil from the liquid light phase outlet of the separator back to the lubricant oil tank, means for adding at least one liquid separation aid to the contaminated oil upstream of the separator inlet.

13 . The system according to claim 12 , wherein the system further comprises a motor connected to said lubricant oil tank, and wherein the motor has an effect of at least 1 MW.

14 . The system according to claim 13 , wherein the motor is a two stroke engine or a four stroke engine.

15 . The system according to claim 12 , further comprising a mixer for mixing the added liquid separation aid to the contaminated oil upstream of the separator inlet.

16 . The method according to claim 2 , wherein the at least one liquid separation aid is labelled.

17 . The method according to claim 3 , wherein the at least one liquid separation aid is labelled.

18 . The method according to claim 2 , wherein the step of adding at least one liquid separation aid to contaminated lubricant oil further comprises mixing the contaminated lubricant oil and the liquid separation aid before supply to the three-phase centrifugal separator.

19 . The method according to claim 3 , wherein the step of adding at least one liquid separation aid to contaminated lubricant oil further comprises mixing the contaminated lubricant oil and the liquid separation aid before supply to the three-phase centrifugal separator.

20 . The method according to claim 4 , wherein the step of adding at least one liquid separation aid to contaminated lubricant oil further comprises mixing the contaminated lubricant oil and the liquid separation aid before supply to the three-phase centrifugal separator.

Assignees

• Alfa Laval Corp Ab

Inventors

• Wase Claes
• Englund Mats

Classifications

• C10N2020/055

  Particles related characteristics · CPC title

• C10M175/0058

  by filtration and centrifugation processes; apparatus therefor · CPC title

• B01D21/0042

  Baffles or guide plates · CPC title

• B01D21/01

  using flocculating agents (for purifying water C02F1/52; for liquid radioactive waste G21F9/10) · CPC title

• C10N2030/02

  Pour-point; Viscosity index · CPC title