CH631739A5 - Process for the production of lubricating oil - Google Patents

Description

An object of this invention is to provide a universally applicable process for the production of a high purity lubricating oil base from used lubricating oils with high detergents.

The used lubricating oils treated by the process which is the subject of the invention are first of all the oils set aside after use as a lubricant in internal combustion engines such as crankcase oils, for example in petrol engines. or diesel engines. Other sources of used oils include steam turbine oils, transmission and transmission oils, steam engine oils, hydraulic oils, heat transfer oils and the like.

The oils used for the abovementioned uses are the lubricating sections of the refining of paraffinic, mixed or naphthenic crude oil. Their viscosity is generally between about 20 and about 400 centistokes at 38 ° C (100 to 1,800 SUS at 100 ° F). The oils also contain various additives such as oxidation inhibitors (for example, barium alcoyithiophosphates, calcium and zinc, di-t-butyl-p-creat-30 sol, etc.), anti-friction agents ( for example, organic lead compounds such as diorganophosphorodithioates, zinc dialkoyldithiophosphates, etc.), corrosion inhibitors (e.g. calcium and sodium sulfonates, etc.), dispersants (e.g. sulfonates and calcium and barium phenates, etc.), viscosity index correctors (e.g. polyisobuty-lenes, poly- (alkylstyrenes), etc.), detergents (e.g. calcium and barium of alkylbenzene sulfonic acids) and detergents of the type without combustion residue such as alkylated succinimides, etc.

40 If desired, the water entrained in the untreated used lubricating oil can be removed before using it in the process which is the subject of the invention. Such separation can easily be carried out by elimination of the aqueous phase which can be found in the storage tanks for used lubricating oils.

The treating agents consisting of ammonium salts useful for the process which is the subject of the present invention are preferably chosen from the group consisting of ammonium sulfate, ammonium bisulfate, ammonium phosphate, mono -50 ammonium hydrogen phosphate, ammonium dihydrogen phosphate, as well as their mixtures.

In addition, if desired, precursors of said ammonium salts can be used in place of some or all of the ammonium salt. Here are some examples of such 55 precursors: ammonium thiosulfate, ammonium polyphosphates such as ammonium metaphosphate, urea sulfate, guanidine sulfate, urea phosphate and guani-dine phosphate. Other precursors which can be used include reactive combinations of ammonia and / or ammonium hydroxide 60 with sulfuric acid and / or phosphoric acid and / or a hy-drogeno-sulphate or ammonium phosphate, that is to say ammonium bisulfate, ammonium monohydrogenphosphate, and / or ammonium dihydrogenphosphate. When the precursor consists of a combination of such compounds which react with each other to give the desired salt in situ, the compounds of the combination can be introduced at the same time, or one of the compounds can be added before introduction of the other.

3

631,739

Although the concentration of the treating agent in the aqueous solution of treating agent is not critical and more dilute solutions can be used, the economic efficiency of the process is improved by the use of relatively concentrated solutions so that the amount of water to be removed next is not too large. In general, the concentration of the treating agent in the aqueous solution will be between 30 and 95 percent by weight, for example about 80 percent by weight, of that which an aqueous solution at 25 ° C. saturated with the treating agent would have. . Frequently, there is water in the used oil, and in this case the concentration of the treating agent can be adjusted accordingly.

As a general rule, the treating agent must be used in an amount sufficient at least to react with all the metal compounds contained in the used oil. Although the ratio of the weights of the treating agent to the used oil can vary widely, depending on the nature and concentration of the metal compounds of the oil and the particular treating agent used, it will generally be between 0.002: 1 and 0.05: 1, most often between 0.005: 1 and 0.015: 1, and, in a typical example,

approximately equal to 0.01: 1. Although larger amounts of treating agent can be used, in most cases this would be a waste of treating agent.

Referring to Figure 1 by way of example, the used oil is taken from the storage tank 1 via line 2 to the heater 3. The aqueous treating agent containing monohydrogenphos-ammonium lime from the preparation tank 8 is introduced via line 7, in an amount slightly in excess compared to that required by the reaction with the compounds forming combustion residues contained in the used oil, in line 2 where it mixes. After heating in the heater 3, the hot mixture of oil and resulting treating agent is led by line 4 in the contacting reactor 5 where sufficient stirring is produced, such as that resulting from the action of blades 6 , to ensure complete dispersion of the aqueous treating agent in the oily phase of the mixture introduced into the stirred contacting reactor 5. Although it is preferred, in the present case, to add the aqueous treating agent upstream of the heater 3 because of the relatively small volume of agent used, the aqueous treating agent can be added either downstream of the heater 3 in the line 4, or directly in the contacting reactor 5.

The mixture of used oil and aqueous treating agent is kept in the contacting reactor 5 for a period and under conditions of temperature and pressure sufficient to effect the reaction of the treating agent with practically all of the compounds forming combustion residues present in the used oil.

After sufficient reaction of the compounds forming combustion residues contained in the hot oil with the treating agent, the resulting reaction mass consisting of a continuous oily phase is introduced via line 9 into the upper part of the purifier 10. In one of the concrete forms of the invention, before the emulsion enters the purifier 10, a suspension of filter aid in oil or in a light hydrocarbon originating for example from phase 44, can be added to the system from the preparation tank 11 by line 12.

The filtration aids useful in the practice of the process which is the subject of the invention are chosen from the group comprising diatomaceous earth, perlite and cellulose fibers. In this case, we prefer diatomaceous earth.

In a concrete form of the invention, the upper part of the purifier 10 is maintained at a temperature and under a pressure sufficient to effect the rapid distillation of most of the water and of the light hydrocarbons contained in the mixture, which are therefore extracted and led by line 13 to the phase separator 14 in which a layer of hydrocarbons 15 and a layer of water are formed 16. The layer of hydrocarbons can then be transferred by line 17 to the storage tank 18. The layer of water can be drawn off through line 19 and discarded or used for any desired use, such as, for example, use in a steam boiler.

The resulting residual mixture, which has a sulfuric ash content of about 0.3 to about 10 percent by weight (ASTM D 847-72) without counting the filter aid or the treating agent possibly present, comprising a phase io hot oily which is practically free of water but which contains an excess of treating agent, a little residual water, and filter aid if one is used, in addition to the solids forming combustion residues present originally in, or coming from used oil, crosses down the purifier 15 10.

Although it is not mandatory, it is in the present case preferable, while the oil is still at high temperature, to introduce steam through line 40 into the purifier 10 to aid in the extraction of the constituents lightweight and dual system water. Then, the resulting purified hot oil is brought by line 20 to the filter 21 to remove the materials forming combustion residues entrained in suspension.

Although a filter aid may be added to the emulsion before cleaning, as described above, to facilitate the subsequent separation of the solids from the substantially water-free oily phase, it is preferable to coat the filter 21 with a filtration aid chosen from those which have been mentioned above, applied directly to the filter. If desired, the filter aid can be used both added to the emulsion before it is cleaned and to coat the filter.

In the presently preferred application of the invention, the cake forming on the filter 21 is evacuated by the line 47 and optionally leads to the oven 48 at the outlet of which, after combustion or calcination, the resulting ash containing earth from Diatoms can be sent to waste via line 49 or recycled to the suspension preparation tank 11 for later use in the system.

The filtered oil, essentially freed from the constituents forming combustion residues which it previously contained, i.e. now having a sulfuric ash content of about 0.01 to about 0.3 percent by weight (ASTM D 847-72) not including the excess of treating agent or the filter aid which could have inadvertently passed through the filter, is suitable for a variety of industrial uses such as heating oils without further treatment , in accordance with the overall integrated process which is the subject of the invention. For example, the used oil taken at this stage in the overall treatment system which is the subject of the invention can be used as heating oil, in the composition of greases or for the preparation of so certain types of lubricating oils. . When this is decided, the oil can be drawn from the system through line 23.

However, in the integrated process according to the presently preferred invention, the hot oil is conducted, after filtration, by line 22 to the heater 25 so as to bring the oil to a temperature between 200 and 480 ° C. If desired, a first quantity of hydrogen can be added to it via line 24. The resulting hot oil having undergone the addition of hydrogen then passes through the contacting reactor 26 where the decomposition of the sulfonates takes place. contained in the oil. 60 Although it is preferred in the present case that the contacting reactor contains bauxite or a bed of activated carbon, this unit can use other adsorbents such as those which can be chosen from the group consisting of gel silica, clay, activated alumina, mixtures thereof and their appearance. The adsorbent is used to break down and decompose ammonium salts of sulfonic acids and detergents without combustion residue contained in the oil. The adsorbent is also used to collect a small part of the resulting products and

631,739

4

This prevents the passage of such unwanted decomposition products through the hydrogenation reactor. These adsorbents can be regenerated by conventional means and reused.

Although less desirable, it is possible to omit the contacting reactor 26 and eliminate the small amount of combustion residue products and highly polar materials present in the low residue filtered oil. combustion, by heating the oil to a temperature between 300 and 410 ° C, for example about 380 ° C, in the presence of hydrogen and an adsorbent suspended in the oil. After such treatment, the oil is cooled to a temperature between 60 and 200 ° C, for example about 150 ° C, and filtered again. The above-mentioned adsorbents for use in stationary contacting reactors are suitable for this contact treatment process and give similar results.

Preferably, the adsorbent contains approximately 0.2 to approximately 20 percent by weight of at least one metal chosen from the group consisting of the metals of group VIB and of the group VHI, this percentage by weight being calculated on the total weight. modified adsorbent. This modified adsorbent can, and this is often preferable, be prepared by impregnating the adsorbent with an aqueous solution of a water-soluble compound of a group VIB or group VIII metal, followed by water evaporation. The water soluble compounds preferred in this case for this use are iron compounds such as ferric ammonium oxa-late, ferric ammonium citrate, ferric sulfate, and ferrous ammonium sulfate.

The resulting treated oil is then transferred from the contacting reactor 26 via line 27 to the hydrogenation reactor 28, which is maintained at an elevated temperature which destroys various additive systems originally contained in the oil. . The hydrogen necessary for the desired hydrogenation reaction is introduced into the system by line 29 in communication with line 27 or, if desired, directly in the hydrogenation reactor 28.

In the hydrogenation reactor 28 the oil is subjected to hydrogenation conditions in the presence of a catalyst sufficient to remove the undesirable compounds and the unsaturated materials and to effect the decomposition of the sulfur, oxygen and residual nitrogen bodies.

The catalysts suitable for use in the hydrogenation reactor are chosen from the group consisting of metals of group VIB and group VIII and their combinations, on a refractory support, used in conventional hydrodesulfurization processes.

After the hydrogenation, the resulting oil is brought through line 30 to the separation-reflux column 31 which is used to remove the water and the other by-products from the previous oil treatments. If desired, and particularly when HCl is present, water can be injected into column 31 to assist in the removal of most of the HCl and part of the H2S and NH3 in the form water-soluble salts. The distillation head of column 31 comprising hydrogen, H2S, NH3, and water is led by line 32 to the desulphurization unit 33. This unit, for example a bed of zinc oxide , eliminates H2S. The resulting stream of hydrogen sulfide then passes through line 34 to the cooler 35. The ammonia is then removed, for example by washing with water in a unit (not shown) on line 36. The hydrogen is then reis cycled through line 36 to line 29.

An example of another useful material in unit 33 is iron oxide. Alternatively, a solvent process using substances such as alkanolamines and / or other amines can be employed, the H2S then being oxidized to sulfur by a Claus type process.

The product from the bottom of the column 31 is transferred via line 37 to the lubricating base purifier 38 where an additional steam treatment is carried out by introducing steam through line 39.

The purification, preferably the steam purification, of the oil is essential to the integrated process which is the subject of the invention because it serves to eliminate light hydrocarbon products boiling lower than the oil, such as kerosene or heavy gasoline, which have remained entrained in oil or which are byproducts of hydrogenation. One can also alternatively employ a purification using a gas such as hydrogen.

The resulting purified hot product, consisting essentially of a pure base of lubricating oil, after cooling 35 as permitted by the use of the heat exchanger 25, is then transferred by line 41 to a base tank of lubricating oil (not shown) for storage and subsequent use as an additive free lubricating oil base suitable for reformulation with additives if desired.

40 The distillation head of the purifier 38, essentially composed of heating oil and water, is led by the line 42 to the decanter 43 where a hydrocarbon phase 44 and a layer of water 45 are formed. layer of hydrocarbons 44 is evacuated via line 46 and combined, if desired, with the phase of hydrocarbons stored in tank 18 for later use. The small amount of gas present in line 46 can be removed by reducing pressure.

25

Estimated Operating Parameters

Fig. 1 Ref. no.

3

7

5

Unit description

Heater

Processing agent Contact reactor

Typical values

Temperature 160 ° C. Pressure 14.6 atm (215 psia) Agent: oil weight ratio = 0.01: 1 Temperature 160 ° C. Pressure 14.6 atm (215 psia) Duration 30 minutes

Areas

Approximate Preferred 60-200 ° C.

1-17 atm (atmos.-250 psia)

0.005: 1-0.05: 1 60-200 ° C.

1-17 atm (atmos.-250 psia) 10 minutes — 2 hours

10 Purifier Above:

Temperature 160 ° C. Pressure 1.1 atm (16 psia) Bottom:

Temperature 115 ° C. Pressure 1.1 atm (16 psia)

60-200 ° C.

0.14—1.4 atm (2-20 psia) 60-200 ° C.

0.14-1.4 atm (2—20 psia)

5 631739

14

Separator

Temperature 40 ° C.

0-80 ° C.

of phases

Atmospheric pressure

1—3.1 atm (atmos.-45 psia)

21

Filtered

Temperature 115 ° C.

60-200 ° C.

Differential pressure:

5.4 atm (80 psi) plate filter

0.3-6.8 atm (5-100 psi)

Continuous drum filter

rotary 0.7 atm (10 psi)

0.14-0.95 atm (2-14 psi)

48

Oven

Temperature 760 ° C.

650-870 ° C

Atmospheric pressure

1 atm approximately

12

Auxiliary

Weight ratio

auxiliary filtration: oil = 0.01: 1

0: 1-0.15: 1

24

Charge

hydrogen

111 vol./vol. oil

80-3000 vol./vol. oil

25

Heater

Temperature 370 ° C.

200-480 ° C.

Pressure 50 atm (735 psia)

10.2-204.1 atm (150-3000 psia)

26

Reactor of

Temperature 370 ° C.

200-480 ° C.

put in contact

Pressure 50 atm (735 psia)

10.2-204.1 atm (150-3000 psia)

28

Hydrogenator

Temperature 360 ° C.

200-430 ° C.

Pressure 49.7 atm (730 psia)

10.2-204.1 atm (150-3000 psia)

29

Charge

hydrogen

222 vol./vol. oil

80-3000 vol./vol. oil

31

Reflux

Temperature 325 ° C.

290-400 ° C.

Pressure 48 atm (705 psia)

40.8-54.4 atm (600-800 psia)

33

Unit of

Temperature 290 ° C.

150-430 ° C.

desulfurization

Pressure 47.6 atm (700 psia)

6.8-204.1 atm (100-3000 psia)

35

Cooler

Inlet temperature 290 ° C.

260-370 ° C.

Outlet temperature 55 ° C.

40-95 ° C.

38

Purifier

Temperature 370 ° C.

280-395 ° C.

Pressure 1.4 atm (20 psia)

1-3.4 atm (atmos.-50 psia)

43

Decanter

Temperature 55 ° C.

0-80 ° C.

Pressure 1.1 atm (16 psia)

1-3.1 atm (atmos.-45 psia)

In the table below are given the standard compositions of the main products for the operating conditions set out above.

40

Table I

Kilograms of products per day

45

Product no.

2

7

9

20

22

24

29

30

32

34

37

42

46

41

Oil

3016

3016

3016

2926

2872

14.5

14.5

2857

14.5

14.5

2843

Metals plus P *

23.2

S *

6.8

5.9

5.9

5.9

<0.5

<0.5

<0.5

o **

22.7

20.4

20.4

20

<0.5

<0.5

<0.5

not*

4.5

4.5

4.5

4.5

<0.05

<0.05

<0.05

h2o

189

63.6

253

0.9

0.9

24.5

24.5

27.7

145

nh3

1.8

1.8

9.1

9.1

9.1

h2s

6.4

6.4

Hydrocarb.

light

136

136

68.1

68.1

125

84

84

40.9

40.9

40.9

(nh4) 2hpo4

31.8

ch4

30.4

30.4

62.2

59.9

59.9

2.3

2.3

2.3

h2

30

30.4

52.2

51.8

51.8

0.5

0.5

0.5

Insoluble

in the oil

58.1

58.1

Earth

diatoms

31.8

* Present in combined form in used oil.

»» Present in combined form in used oil, not including water.

631,739

6

In another concrete form of this invention, as shown in FIG. 2, the used oil is transferred from the storage tank 101 by the line 102 to the heater 103 and to the contacting reactor 106. The aqueous treating agent containing ammonium monohydrogen phosphate from the preparation tank 105 is introduced via line 104. If desired, the agent precursors, ammonia, phosphoric acid and water can be introduced into the hot oil downstream of the heater 103, thus forming the treating agent in situ in line 102 and the contacting reactor 106. The oil coming from the heater 103 is brought, mixed with the treating agent, to the first reactor contacting 106 in which the mixture is kept under stirring for a time sufficient for the reaction of the constituents forming combustion residues contained in the oil. Preferably, a stream of recycled mixture is passed through line 152, pump 153 and then through heater 154 before it returns to the contacting reactor 106, thereby providing heat and agitation to the contents of the contacting reactor. . An agitator can also be used.

Then the mixture is transferred via line 107 to the second contacting reactor 109, which is maintained at a temperature between about 110 ° C and about 140 ° C, for a time sufficient to carry out the distillation of most of the water and at least part of the light hydrocarbons present. Thus, while the mixture is maintained in the contacting reactor 109, practically all of the water and at least part of the light hydrocarbon constituents of the mixture are eliminated by line 110 and led to the separator 111 where a layer d is formed. and a layer of water. The hydrocarbon phase can then be withdrawn and rejected or used for any desired use. Preferably, a stream of recycled mixture is passed through the line 155, the pump 156 and then through the heater 108 before it returns to the contacting reactor 109, thereby providing heat and agitation to the contents of the reactor. An agitator can also be used.

The resulting residual mixture containing a hot oily phase essentially free of water is transferred via line 114 to a third contacting reactor 116 where the mixture is added with diatomaceous earth which is introduced into reactor 116, preferably under the form of a suspension in light hydrocarbons recovered during the integrated process, via line 118 coming from the preparation tank 119. Preferably, a stream of recycled mixture is passed through line 157, pump 158 and then through the heater 115 before returning to the contacting reactor 116, thereby providing heat and agitation to the contents of the reactor. Water and residual hydrocarbons, if any, are removed from the contacting reactor 116 via line 159.

If desired, one, two, or all of the contacting reactors 106, 109 and 116 can be fitted with sleeves heated by steam or other heat source to help maintain the contents of the reactors at desired temperatures. One, two, or all of the contacting reactors 106, 109 and 116 may be equipped with agitators to provide additional agitation. In an installation capable of operating but less desired in the present case, an agitator can be used in one or more of the three contacting reactors instead of the recycling system employed in the corresponding reactor or reactors, any additional heating being provided by heaters on the line upstream of the reactors and / or heating sleeves around the reactors. In addition, if desired, the process can be carried out without the contacting reactor 116, in which case the diatomaceous earth can be brought via line 118 to line 114, from which the resulting mixture comprising oil, solid impurities and diatomaceous earth can be directly transferred to the filter 121. If desired, one, two or all of the lines 102, 107 and 114 can lead into the recycling circuits of the contacting reactors 106, 109 and 116 respectively, that is to say in the lines 152, 155 and 157 respectively, instead of leading directly into the respective reactors as shown in FIG. 2.

After addition of diatomaceous earth, the resulting hot mixture is transferred via line 117 to the filter 121, which can optionally be coated with diatomaceous earth. If desired, other filtration aids such as perlite or cellulose fibers can be used.

The cake forming on the filter 121 is evacuated through the line 147 and possibly leads to the oven 148 at the outlet of which, after combustion or calcination, at least part of the resulting ash-15 dre containing diatomaceous earth can be sent discarded by line 149 or recycled through lines 120 and 160 into the suspension preparation tank 119 for later use in the system. New diatomaceous earth is added via line 160. The light hydrocarbons 2c used for the preparation of the suspension can be recovered during the integrated process and can be brought to tank 119 through line 151.

By carrying out the process corresponding to this application of the invention, a beneficial increase is obtained in the rate of filtration of the oil through the filter 121 when the oil-reagent mixture is maintained in its form for a period of at least 10 minutes at a temperature between 60 and 120 ° C, before continuing the process.

Thus the filtered hot oil, essentially freed from the constituents forming combustion residues which it previously contained, is suitable for a variety of industrial uses and can be drawn from the system by line 123.

However, in the integrated process according to the presently preferred invention, the hot oil is led, after filtration, by line 122 to the heater 125 so as to bring the oil to a temperature between 200 and 480 ° C, to then treat it in a manner similar to that shown in Figure 1. If desired, a first amount of hydrogen can be added to it by line 124. The resulting hot oil having undergone the addition of hydrogen then passes through the contacting reactor 126 where the decomposition of the sulfonates contained in the oil takes place.

Although it is preferred in the present case that the contacting reactor 126 contain bauxite or a bed of “active carbon”, this unit can use other adsorbents such as those which can be chosen from the group consisting of silica gel, clay, activated alumina, mixtures thereof and the like. The adsorbent is used to break down and decompose ammonium salts of sulfonic acids and detergents 5 (1 without combustion residue contained in the oil. The adsorbent also serves to collect a small part of the resulting products and prevents thus the passage of such undesirable decomposition products in the hydrogenation reactor These adsorbents can be regenerated by conventional means and reused.

Although less desirable, it is possible to omit the contacting reactor 126 and eliminate the small amount of combustion residue products and strongly polar materials present in the filtered oil with low content of 60 combustion residues, by heating the oil to a temperature between 300 and 410 ° C, for example around 380 ° C, in the presence of hydrogen and an adsorbent suspended in the oil. After such treatment, the oil is cooled to a temperature between 60 and 200 ° C, for example about 150 ° C, and filtered again. The aforementioned adsorbents for use in fixed bed contacting reactors are suitable for this contact treatment process and give similar results.

7

631739

Preferably, the adsorbent contains about 0.2 to about 20 percent by weight of at least one metal selected from the group consisting of metals of group VIB and group VIII, this percentage by weight being calculated on the total weight modified adsorbent. This modified adsorbent can be prepared by impregnating the adsorbent with an aqueous solution of a water-soluble compound of a group VIB or group VIII metal, followed by evaporation of the water. The water-soluble compounds preferred in this case for this use are iron compounds such as ferric ammonium oxalate, ferric ammonium citrate, ferric sulfate and ferrous ammonium sulfate.

The resulting treated oil is then transferred from the contacting reactor 126 via line 127 to the hydrogenation reactor 128, which is maintained at an elevated temperature which destroys the various systems of additives previously added to the base d original lubricating oil. The hydrogen necessary for the desired hydrogenation reaction is introduced into the system via line 129 in communication with line 127 or, if desired, directly into the hydrogenation reactor 128.

In the hydrogenation reactor 128, the oil is subjected to hydrogenation conditions in the presence of a catalyst sufficient to remove the undesirable compounds and the unsaturated materials and to effect the decomposition of the sulfur, oxygen and residual nitrogen bodies so as to providing an oily product capable of undergoing further purification to give a base of lubricating oil.

The catalysts suitable for use in the hydrogenation reactor 128 are chosen from the group consisting of the metals of group VIB and of group VIII and their combinations, on a refractory support, used in the conventional hydrodesulfurization processes.

After the hydrogenation, the resulting oil is brought via line 130 to the separation-reflux column 131 which serves to remove the water and various other by-products from the previous oil treatments. If desired, and especially when HCl is present, water can be injected into column 131 to assist in the removal of most of the HCl and part of the H2S and NH3 as water-soluble salts. The distillation head of column 131 comprising hydrogen, H2S, NH3, and water is led by line 132 to the desulfurization unit 133. This unit, for example a bed of zinc oxide, eliminates H2S. The resulting stream of desulphurized hydrogen then passes through line 134 to the cooler 135. The ammonia is then removed, for example by washing with water in a unit eliminating the ammonia (not shown) on line 136. L hydrogen is then recycled through line 136 in line 129.

An example of another useful material in unit 133 is ic consisting of iron oxide. Alternatively, a solvent process using substances such as alkanolamines and / or other amines can be used, the H2S then being oxidized to sulfur by a process of the Claus type.

The product from the bottom of the column 131 is transferred via line 15137 to the lubricating base purifier 138 where additional steam treatment is carried out by introduction of steam through line 139.

The purification, preferably the steam purification, of the oil is essential to the integrated process forming the subject of the invention 2c because it serves to eliminate the light hydrocarbon products boiling lower than the oil, such as kerosene or heavy gasoline, which have remained entrained in oil or which are by-products of hydrogenation. One can also alternatively employ a purification using a gas such as hydrogen.

The resulting purified hot product, consisting essentially of a pure base of lubricating oil, after cooling as permitted by the use of the heat exchanger 125, is then transferred by line 141 to a base tank of lubricating oil ( not shown) for storage and subsequent use as a lubricant oil base without additives suitable for reformulation with additives if desired.

The distillation head of the purifier 138, essentially composed of heating oil and water, is led by the line 142 to the decanter 143 where a hydrocarbon phase 144 and a layer of water 145 are formed. The layer of hydrocarbons 144 is evacuated via line 146 and combined, if desired, with the hydrocarbon phase stored in tank 113 for later use, or recycled to the tank for preparing the filtration aid 119 via line 151. The small amount of gas present in line 146 can be eliminated by reducing the pressure.

Estimated Operating Parameters

Fig. 2

Description

Typical values

Areas

Ref. no.

of unity

Preferred Approximates

103

Heater

Temperature 95 ° C.

60-120 ° C.

Pressure 1,2 atm (17 psia)

1—17 atm (atmos.-250 psia)

104

Agent

Weight ratio

treating oil agent = 0.01: 1

0.005: 1-0.05: 1

106

Reactor of

Temperature 95 ° C.

60-120 ° C.

put in contact

Pressure 1,2 atm (17 psia)

1-3.4 atm (atmos.-50 psia)

Duration 30 minutes

10 minutes-2 hours

109

Reactor of

Temperature 125 ° C.

110-140 ° C.

put in contact

Pressure 1.1 atm (16 psia)

0.3-1.7 atm (5-25 psia)

Duration 30 minutes

10 minutes- 2 hours

116

Reactor of

Temperature 160 ° C.

140-200 ° C.

put in contact

Pressure 1.1 atm (16 psia)

0.3-1.7 atm (5-25 psia)

Duration 30 minutes

10 minutes-2 hours

111

Separator

Temperature 40 ° C.

0-80 ° C.

out of phase

Atmospheric pressure

1-3.1 atm (atmos.-45 psia)

121

Filtered

Temperature 115 ° C.

60-200 ° C.

Differential pressure:

5.4 atm (80 psi) plate filter

0.3-6.8 atm (5-100 psi)

Continuous drum filter

rotary 0.7 atm (10 psi)

0.14-0.95 atm (2-14 psi)

631739

8

148

Oven

Temperature 760 ° C.

650-870 ° C.

Atmospheric pressure

1 atm approximately

118

Auxiliary

Weight ratio

auxiliary filtration: oil = 0.01: 1

0: 1-0.15: 1

124

Charge

hydrogen

111 vol./vol. oil

80-3000 vol./vol. oil

125

Heater

Temperature 370 ° C.

200-480 ° C.

Pressure 50 atm (735 psia)

10.2-204.1 atm (150-3000 psia)

126

Reactor of

Temperature 370 ° C.

200-480 ° C.

put in contact

Pressure 50 atm (735 psia)

10.2-204.1 atm (150-3000 psia)

128

Hydrogenator

Temperature 360 ° C.

200-430 ° C.

Pressure 49.7 atm (730 psia)

10.2-204.1 atm (150-3000 psia)

129

Charge

hydrogen

222 vol./vol. oil

80-3000 vol./vol. oil

131

Reflux

Temperature 325 ° C.

290-400 ° C.

Pressure 48 atm (705 psia)

40.8-54.4 atm (600-800 psia)

133

Unit of

Temperature 290 ° C.

150-430 ° C.

desulfurization

Pressure 47.6 atm (700 psia)

6.8-204.1 atm (100—3000 psia)

135

Cooler

Inlet temperature 290 ° C.

260-370 ° C.

Outlet temperature 55 ° C.

40-95 ° C.

138

Purifier

Temperature 370 ° C.

280-395 ° C.

Pressure 1.4 atm (20 psia)

1-3.4 atm (atmos.-50 psia)

143

Decanter

Temperature 55 ° C.

0-80 ° C.

Pressure 1.1 atm (16 psia)

1-3.1 atm (atmos.-45 psia)

In the table below are given the standard compositions of the main products for the operating conditions set out above.

Table II

Kilograms of products per day

30

Product no. 102 104 107 117 122 124 129 130 132 134 137 142 146 141

Oil

3016

3016

3016

2926

2872 14.5

14.5 2,857 14.5

14.5 2843

Metals plus P *

23.2

S *

6.8

5.9

5.9

5.9

<0.5

<0.5

<0.5

o * "

22.7

20.4

20.4

20

<0.5

<0.5

<0.5

NOT"

'4.5

4.5

4.5

4.5

<0.05

<0.05

<0.05

h2o

189 63.6

253 0.9

0.9

24.5

24.5

27.7

145

nh3

1.8

1.8

9.1

9.1

9.1

h2s

6.4

6.4

Hydrocarb.

light

136

136 68.1 68.1

125

84

84

40.9

40.9

40.9

(nh4) 2hp04

31.8

ch4

30.4

30.4

62.2

59.9

59.9

2.3

2.3

2.3

h2

30

30.4

52.2

51.8

51.8

0.5

0.5

0.5

Insoluble in oil 58.1 58.1 Diatomaceous earth 31.8

»Present in combined form in used oil.

»» Present in combined form in used oil, not including water.

As used in this text, the term "flash distillation" is assumed to represent a distillation in which all or almost all the heat used to transform the liquid into vapor in the distillation process is supplied in the form of heat sensitive to mixture comprising the liquid when this mixture is under a given pressure, the vaporization of the liquid then occurring by reduction of the pressure. Thus, "flash distillation" is used in the process of FIG. 1 during the removal of water and light hydrocarbons from the mixture which leaves the contacting reactor 5. As used in this process. text, the term "distillation" is assumed to represent the process in which at least most of the heat required to transform the liquid into vapor is supplied to the mixture comprising the liquid when this mixture is approximately at the pressure at which the vaporization takes place. product. Thus, “distillation” is used in the process of FIG. 2 during the removal of water and light hydro-carbides from the contacting reactors 109 and 116.

VS

2 sheets of drawings

Claims (7)

631,739 1. Process for the production of a lubricating oil base practically free of combustion residue from a used lubricating oil containing compounds forming combustion residues, process which comprises: a) bringing said used lubricating oil into contact with an aqueous solution of an ammonium salt, dispersing said salt in said oil, and reacting said salt with said compounds forming combustion residues and b) recovering the resulting oily phase as a product; the process being characterized by step c) extracting most of the water and light hydrocarbons from the mixture of used oil, solids and treatment agent resulting from step a). 2. Method according to claim 1, characterized in that water and light hydrocarbons are extracted by distillation. 2 claims 3. Method according to claim 2, characterized in that practically all the water and light hydrocarbons are extracted by flash distillation. 4. Method according to claim 3, characterized in that the water and light hydrocarbons of said mixture are rapidly distilled at a temperature between 60 and 200 ° C and under a pressure between 0.14 and 1.4 atm. 5. Method according to one of claims 1 to 3, characterized in that the treated oil is recovered by filtration of the mixture resulting from the used oil and the solids. 6. Use of the lubricating oil obtained in accordance with the method according to claim 1, characterized by the fact that the oil obtained is hydrogenated. 7. Use according to claim 6, characterized in that the effluents comprising sulfur and hydrogen originating from said hydrogenation are brought into contact with zinc oxide or iron oxide to remove the sulfur. In recent years an increasing number of additives such as detergents, pour point lowerers, oxidation inhibitors and viscosity index correctors have been used in petroleum lubricating oils. While these additives have greatly improved the performance of lubricating oils, they have also significantly increased the work required to recover such oils after use. More particularly, the resins which normally form in oil during its use, as well as carbon, dirt, metallic debris from wear and other impurities, remain in suspension in the engine thanks to modern detergent additives, such as as the calcium and barium salts of the alkylbenzene sulfonic acids, and detergents of the type without combustion residue such as the alkylated succinimides. In the end, suspended impurities are therefore largely removed from the engine during oil changes and remain in the drained oil. Economically removing impurities from used oils with a high detergent content so that this oil can be reused is no less of a task for the reclaimer and becomes more difficult as more effective detergents are added to the oils. In addition, modern additive systems have presented an additional problem that such additives must be extracted from the oil base if the resulting lubricating oil base is to be suitable for the reformulation of a lubricating oil. High quality. The purification methods used in the past for the separation of carbon and dirt particles from lubricating oils containing no detergent additives or only relatively ineffective additives cannot be used with satisfaction to purify oils with high levels of current detergent. Since almost all mineral lubricating oils used today are of the high detergent type containing many additives, and since service stations tend to put all crankcase drain oils in the same tank, practically all used lubricating oils available for re-refining or recovery processes have the properties of a high detergency rate.