US1698257A - Process of reclaiming used lubricating oil - Google Patents

Description

Jan. 8, 1929. 1,698,257

G. L. CHERRY l PROCESS OF RECLAIMING USED LUBRICATING OIL Filed May 5, 1926 H H II H II II I! an. aaaiiuai 0 I Patented Jan. 8, 1929.

UNITED STATES GEORGE L. CHERRY, OF LIBERTYVILLE,

ILLINOIS, ASSIG NOR TO THE LAVAL SEPARATOB COMPANY, NEW YORK, N. Y., A CORPORATION. OF NEW JERSEY.

/ 1 PROCESS OI BECLAIMING USED LUBRICATING OIL.

Application filed May '5,

My invention relates to the reclamation of.

used lubricating oil and is particularly applicable to the reclamation of used car axle oil.

5 This dirty oil consists of so tight an emulsion of water, very fine dirt and oil that even when heated to about 210 F. for several days it shows no sign of separation.

The object of the invention is to so thoroughly remove impurities from the oil that itlwill be suitable for re-use in place of new 01 Attempts have been made, without success, to recover this oil by adding solutions of salts and alkalies.

I have found that the addition of from one to three per cent of an alkali, Such as caustic soda, in a dry state, to the dirty oil, while it isheated to about 210 R, will cause, after 2 the soda has been dissolved in the water press ent, a slow separation of most of the dirt and water from the oil, which is left in such a condition that the remaining dirt and water may be easily removed by a centrifuge;

The process is not dependent for its'exe- 1 cution on the use of any particular apparatus, but the apparatus shown in elevation in the accompanying drawing affords a means for carrying out the process with great elliciency. A closed steam-jacketed conical-bottomed treating tank a has, attached to its top, a relief valve 6 and an inwardly opening check valve 0. Through a pipe d steam may be supplied to the jacket, which is provided with a condensate outlet 6. At the apex'of the conical' bottom, there is provided a large sludge draw-01f pipe f with a controlling valve g.

Entering the pipe f above the valve 9 is an oil inlet pipe It with a valve i, fed by a pump y from a sump tank k.

Within the treating tank, float Z supports a swinging draw-off pipe m-leading, through a pipe n, with valve 0, to a centrifugal oil purifier'p. From the pipen a branch 9 with a valve r leads to the sump tank 70.

A hot water inlet to the pipe n is provided through a pipe 8 with valve t.

The centrifugal separator has three outlets, the bottom one u, adapted to discharge the heavy constituents, discharging into a pipe 4; leading to the sewer; the middle one w, adapted to discharge the light constituent, discharging into a pipe as leading to a clean oil storage tank; and the upper one 3 being 1926. Serial naioass'z.

an overflow arranged to discharge into'the sump tank is. Y

On the side of the treating tank a is a series of try cocks z. A manhole a with a tightcover is provided in the top of the tank to permit, examination of the inside of the tank..

A pipe 10 enters through the tank top, extends nearly to the bottom, and ends in a horizontal radial nozzle 11 for a water jet to flush out any solids that may collect on the bottom. A valve 12 controls the flow.

In order to carryout my process, the above described apparatus is operated in, preferably, the following manner:

Dirty oil, as collected, is put into the sump tank is until there is enough for a batch. It is then pumped into tank a through pipe h and heated. When the temperature is nearly 210 F., the pump j is started and the valve 0 opened enough to keep the inlet to the pump covered. Dry ground caustic soda isnow poured slowly into the sump tank, wherein it meets the stream from the pipe 9. The addition of soda is continued until about 1% per cent of soda by weight of oil, or about twelve pounds of caustic soda per 100 gallons of oil, has been added. (While some oils will not need more than one per cent, others may need as much as three per cent, though I have found 1 per cent suitable for many oils.) The circulation through the sump tank, pump, treating tank, etc., is continued until all the soda is dissolved and thoroughly mixed with the oil. The oil is then allowed to stay in the treating tank for from ten to fourteen hours with the, temperature maintained in the neighborhood of 210 F. At the end of that tinietherewill be found in' the bottom of the tank a layer of sludge,

above that a layer of water, and above that ture of oil and water to enter the centrifugal.

No exact ratio of the proportion of water to oil is necessary, but, a ratios-of three to fi ve'- ity adapted for use'instead of new oil. The

float-supported swinging pipe permits drawing off all the oil without also drawing off any of the sludge from the bottom of the tank, w

After all the oil has been drawn off and run through the oil purifier, the valve 9 may be opened and all the sludge and water allowed to escape to the sewer; A'sudden flow of water from the jet 11 will wash out the last of the sludge.

No fi res have been iven above for the rate of eed to the oil purifier, as that will depend on the make and size of the machine. I have found that a De Laval No. 300 machine can properly treat about twenty-five gallons per hour of oil, anda No. 600 machine of the.

same make about seventy-five gallons per hour.

As stated in the preliminary remarks, I know that it is old to treat dirty oils with solutions of salts and alkalies. I have tried soda is a known treating agent for use in the purification of contaminatedoil, and I made such solutions and even dry sodium chloride on the described oil without success while the above described process, evolved after much experimental work, has proven very successful and is now in regular use.

' While I prefer to use caustic soda as the V treating agent, certain other alkalies, such as caustic potash, are also efficient, and itis notiintended, in claiming caustic soda, to exclude equivalents. A solution of caustic no. claim, broadl to theuse of caustic soda or any other a ali or treating agent, my

rocess involving the novel features particutaminated with water and solids in order arly pointed out in the claims.

While I have given a certain temperature for treatment and certain proportions of reagents,"I do not wish to limit myself to precisely 210 Frnor to proportions except in those claims where proportions are distinctly specified, A temperature just below the boiling point of water and the specified proportions, however, have given excellent results and seem to necessarily characterizethe most eflicient way of executing the process. Good, though somewhat less efficient, results may be obtained with other proportions of the reagent and at a temperature as low as 180 F. at atmospheric pressure. In specifyin a temperature approximating or in the nel hborhood of 210 F., I do not mean to exc ude a variation of five degrees or thereabouts from that precise temperature at atmosphericpressure or any equivalent temperature at a different pressure.

Having now fully described 'my invention,

what I claim and desire to protect by Letters Patent is:

1. The process of purifying used oil contaminated with water and solids in order to reclaim it for re-use, which comprises heating the impure oil to not above approximately210 Rand mixing there'with caustic soda in a substantially dry state until the soda is dissolved and subsequently separating the oil from the impurities.

2. The process of purifying used oil contaminated with water and solids in order to reclaim it for re-use, which comprises heat.- ing the impure oil to not above approximately 210 F. and mixing with it caustic soda in a substantially dry state, settling to prec'ipitate the major part of the impurities and treating agent, and subjecting the oil to centrifugal force 0 separate therefrom such portion of the treating agent as is suspended I therein.

3. The process of purifying used oil contaminated with water and solids in order to reclaim it for re-use, which comprises heating the impure oil to not above approximately 210 F. and mixing with it caustic soda in a substantially dry state, settling to pre cipitate the major part of the impurities and treating agent, and washing and centrifugal ly purifying the oil. a 4. The process ofpurifying used oil contaminated with water and solids in order to reclaim it for re-use, which comprises heating the impureoil to a temperature just below the boiling point of water and mixing with it caustic soda in a substantially dry state, settling to precipitate the major part of the impurlties and the treating agent, and subjecting the oil to centrifugal force to sepa rate therefrom the remainder of the impurities and treating agent.

5. The process of purifying'used oil conto reclaim it for re-use, which comprises heating the impure oil to not above approximately 210 F. and mixing withit not less than about one per cent of dry caustic soda, settling to precipitate the major part of the impurities and treating agent, and subjecting the oil to centrifugal force to separate therefrom the remainder of the impurities tling to precipitate the major part of'the impurities and treating agent, and centrifugally purifying the oil.

7. The process of purifying used oil contaminated with water and solids in order to reclaim it for re-use, which comprises heating the impure oil to a temperature just below the boiling point'of Water and mixing with it not less than about one per cent. of caustic soda in a substantially dry state, settling for not less than about eight hours, removing the supernatant, partially purified oil, washing it 'With Water, and centrifugally separating the oil from the wash Water and the remaining impurities and treating agent. 1

8. That process of reclaiming used oil containing Water and solid impurities Which comprises heating to nearly the boiling point of Water, dissolving caustic soda in a substantially dry state in the contained water and mixing with the entire mass, keeping the mass hot While allowing settlement until the major-portion of the solid impurities is in a bottom sludge layer, a major portion of the oil in a top layer and some of the water in an intermediate layer, drawing oi? the supernatant oil, adding clean water, and centrifugally removing the remaining traces of solid impurities and caustic soda with the Water.

9. The process of purifying used'oil contaminated with Water and solids in order to ing the impure oil to a temperature just below the boiling point of Water and mixing with it caustic soda in a substantially dry state until the soda is dissolved and subsequently separating the oil-from the impurities.

In testimony of which invention, I have hereunto set my hand, at Chicago, Illinois, on this 1st day ofMa, 1926.

' E0. L. CHERRY.

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