DE1035830B - Process for sweetening mercaptan-containing hydrocarbon oils - Google Patents

Description

The invention relates to a process for sweetening sour, ie mercaptan-hydrocarbon oils, and especially the preparation of sweetened, color-stable oils, which boil in the range of about 150-340 ⁰ C, such as that commonly referred to as distillate fuels heavy naphtha, kerosene, diesel oil, fuel oil and heating oil .

One of the most widely used methods of getting rid of the offensive odor of almost all naturally occurring Hydrocarbon oils, especially those obtained by distilling crude oil, are the so-called Cuprichloride process as described in * Oil and Gas Journals, March 22, 1947, p. 195. It was found, however, that using cuprichloride sweetened oil is not color-fast, especially at elevated temperatures. For those boiling in the light gasoline range Oiling can easily remedy this color instability by adding very small amounts of a copper deactivator will. Such deactivators are relatively ineffective when oils are made color-fast that boil higher than in the light petrol range. In the case of oils from some raw oils, e.g. B. West Texas Petroleum, the cuprichloride process leads to such a deterioration in color that it is fresh sweetened oil is of completely unsatisfactory color.

A process has now been found for sweetening mercaptan-containing hydrocarbon oils in which the oil is brought into intimate contact in the liquid state in the presence of free oxygen with a catalyst which consists essentially of an inert adsorbent, a copper salt and water and which is characterized by this that the treatment is ^{carried out between 88 and HO 0} C, the catalyst contains at least 8 percent by weight of water and the copper salt is copper sulfate and / or a preferably water-soluble copper sulfonate.

The preferred water-soluble copper sulfonates are copper alkyl sulfonates having no more than 10 carbon atoms in the molecule or copper aryl sulfonates with not more than a total of 8 carbon atoms in the optionally alkyl substituents present.

A catalyst is preferably used which consists essentially of 8 to 45 percent by weight of water and of the inert adsorbent and the copper salt in a weight ratio of 12: 1 to 3: 1, and a treatment ^{temperature between 93 and 104 °} C. is selected.

The usability of the catalyst can be increased by introducing oxygen or a free oxygen-containing one Gas can be extended into the oil before it meets the catalyst. The procedure only slightly deteriorates the original color of the oil, but results in a color-fast oil, without adding a copper metal deactivator. The drawing explains in a schematic representation a facility for carrying out the procedure.

Process for sweetening hydrocarbon oils containing mercaptan

Applicant:

Standard Oil Company, Chicago, 111. (V. St. A.)

Representative: Dr.-Ing. H. Ruschke, Berlin-Friedenau, and Dipl.-Ing. K. Grentzenberg, Munich 27,

Pienzenauerstr. 2, patent attorneys

Jack H. Krause, Hammond, Ind. (V. St. A.) has been named as the inventor

The present process is applicable to any hydrocarbon oil containing mercaptans. It is particularly useful for distillates such as gasoline, light oil, diesel oil, fuel oil and heating oil. This process can be applied particularly advantageously to distillates boiling above the light gasoline range, since, as mentioned, it is difficult to obtain a color-fast product by the customary cupric chloride process. The following tests were carried out on fuel oil distillates obtained from West Texas and Midcontinent crude oils with the following properties ^:

specific weight

Mercapt number

Saybolt color scale ..
ASTM distillation:

Start of boiling,

10%

50%

90%

maximum

West texas

Raw distillate

0.824

70
+ 19

166 ° C 199 ⁰ C 229 ⁰ C 260 ° C 284 ° C

west

Texas-

Distillate,

with acid

treated

0.821 3

+ 20

166 ° C 186 ⁰ C 218 ° C 263 ° C 29O ⁰ C

Midcon

tinent

Raw-

distillate

0.818

8 + 22

164 ° C 194 ° C 229 ° C 269 ⁰ C 290 ⁰ C

The acid treated West Texas distillate was prepared by treating West Texas raw distillate at 24 grams 98% sulfuric acid per liter of distillate, separation of the sludge, removal of suspended particles, neutralist » 580/530

sizing the oil with caustic alkali and washing out the lye residues with water.

In all tests, the original color of the sweetened oil was determined immediately after washing out or after the catalyst had been separated off, and the color fastness was determined on the basis of the color after accelerated aging. To accelerate aging, 100 cm ^{3 of} the sweetened oil were kept at 93 ° C. in an open beaker for 20 hours. An oil sweetened by means of copper compounds has a satisfactory color fastness during storage if it has a Saybolt color value of + 10 or higher after accelerated aging.

It has been found that by means of copper sulfate or the preferably to be used water-soluble Copper sulfonates in the absence of water sweetening cannot be achieved. The best results were achieved when the catalyst consists of the copper salt, water and an inert adsorbent such as Fuller's earth, attapulgite, silica gel or activated carbon, existed as a carrier. The ones used in the present experiments Catalysts were made by adding a certain amount of water to the copper salt, the specified amount of attapulgite clay was added and the mass was stirred until a uniform mixture Template. (All quantities are based on weight.) The catalyst was a freely flowing, granular material up to a total water content of about 45 percent by weight, based on the sum of Copper salt, solid particles and water. With a higher water content, the catalyst loses its free flowing, granular shape and becomes a muddy mass.

The copper salts are preferably used in the form containing water of crystallization, but it can also be used anhydrous form can be used. The water of crystallization is important when calculating the total water content of the To take into account the catalytic converter.

It has been found that both chemically pure and commercial grade copper sulfate are successful can be used. The copper sulfonates can be made from one of methane, ethane, and butane sulfonic acid or an alkylsulfonic acid mixture consisting of methane, ethane, propane and butanesulfonic acid will. They were preferably made by reacting copper carbonate with the appropriate Sulfonic acids produced. The particular (mixed) copper alkyl sulfonate used in the following examples was a mixture of (30 percent by volume) methyl, (50 percent by volume) ethyl and (10 percent by volume) 2-propyl sulfonic acid, the remainder of 1-propyl and isobutyl sulfonic acids duration. (The preparation of this alkylsulfonic acid mixture was carried out according to that in the USA. Patent 2 433 395.) It was found that the copper alkyl sulfonates with more than 10 carbon atoms are so oil-soluble that the catalyst is quickly destroyed. Likewise are the copper aryl sulfonates with more than 8 carbon atoms in the optionally present alkyl substituents too oil-soluble for the purposes of the present proceedings. We recommend using copper benzene sulfonate or copper toluene sulfonate.

The experiments were carried out as follows: 500 cm ^{3 of} the oil were heated to the treatment temperature in a flask equipped with a stirrer and saturated with oxygen by introducing air. The catalyst, 6 percent by volume based on the oil, was then added and the mixture was kept at the desired temperature for approximately 2 minutes with stirring. If the oil could be sweetened at all by the catalyst in question at the selected treatment temperature, a treatment time of 2 minutes was more than sufficient to achieve a sweetened oil. If the catalyst-oil mixture is stirred well, the sweetening is extremely rapid. The mixture was allowed to settle for about 45 minutes and the treated oil separated. Usually the treated oil was then washed with about 1 part by volume of water to 2 parts by volume of oil, but more or less water can be used. The oil-water mixture was then allowed to settle for about 10 minutes, the oil was decanted and suspended and dissolved water residues were removed through a salt filter. The temperature at which the water wash is carried out is not critical. It has been found that, with many oils, this washing out with water can be omitted without adversely affecting the color stability.

Influence of the treatment temperature

The influence of the treatment temperature in sweetening sour oil was determined using one of 72% by weight Clay, 20 weight percent water and 8 weight percent copper salt existing catalyst examined. The vDoctortest «was used to determine whether the oil was still sour or already sweetened (Shaking the oil with a solution of litharge in sodium hydroxide solution, i.e. sodium plumbite solution; dark cloudiness or precipitation of lead sulfide indicates the presence of sulfur compounds). All color values are on the Saybolt scale related. The starting color is the color of the oil immediately after sweetening (or after washing out with water) and the aging color that after accelerated aging.

Copper salt

Treatment temperature ° C

oil

Color of the treated oil

at first

aged

West Texas oil pre-treated with acid

Sulfate.

Alkyl sulfonate mixture
Toluenesulfonate

*) Do not wash with water after sweetening.

66 angry - - 82 not completely cute yet - --- 93 Sweet 18th 17th 104 Sweet 18th 17th 104 *) Sweet 16 12th 66 angry - -. 82 not completely cute yet - - 93 Sweet 17th 13th 85 not completely cute yet - - 91 Sweet 22nd 19th

5 Copper salt Treatment
temperature ° C oil 6th Color of the treated oil
initially | aged

Sulfate.

Alkyl sulfonate mixture

Sulfate.

Alkyl sulfonate mixture

Midcontinent oil ) angry
not completely cute yet
Sweet
Sweet
Sweet 19th
19th
18th 19th
19th
19th 66
82
93
104
104 * angry
not completely cute yet
Sweet 19th 16 82
93
104 West Texas Crude Oil ! 6 10 82
93
104 16 10 82
93
104 angry
not completely cute yet
Sweet angry
not completely cute yet
Sweet

Do not wash with water after sweetening.

Distillate fuels that are to be used for domestic heating purposes must have a mercapt number below 1. According to the doctor's test, this corresponds to an oil that is “not yet completely sweet”. The present proceedings makes it possible to produce a satisfactory oil in terms of sweetening and color fastness when the reaction is carried out at about 88 ° C. A completely sweetened oil is obtained by treating at about 93 ° C. Self an oil which is very contaminated with respect to the mercaptan content leads at a treatment temperature of about 104 ° C to a satisfactory product.

Influence of the water content

The influence of the total water content of the catalyst on acid oil sweetening was investigated by changing the total water content at a constant weight ratio of clay to copper sulfate of 9: 1 became.

water
salary
Weight
percent Treatment
lung
tempe-
temperature ⁰ C oil Color of
treated oil
initially | aged West Texas Crude Oil Z 3.6
3.6 82
104 angry
angry - 10 8.7
8.7 93
104 angry
angry - 4th
0 20.0
20.0
20.0 82
93
104 angry
not yet
totally cute
Sweet 16 43.0
43.0
43.0 82
93
104 angry
Sweet
Sweet 10
10

water Treatment salary lung Weight tempe- percent temperature ⁰ C

oil

Color of
treated oil

initially ί aged

West Texas oil pre-treated with acid

3.6
3.6 82
104 angry
angry 8.7
8.7 82
99 angry
Sweet 20.0
20.0
20.0 66
82
93 angry
not yet
totally cute
Sweet 43.0
43.0
43.0 82
93
104 angry
not yet
totally cute
Sweet

18 I 8

-

18th

12th

17th

12th

From this it can be seen that the mercapto number of the oil being treated has some influence on the minimum water content required to obtain a satisfactory end product. While the acid pretreated oil with the mercapt number 3 ^{can be sweetened at around 88 °} C. and a water content of around 8%, the oil with the mercapt number 70 at around 93 ^° C. requires a water content of 20%. Basically, when sweetening sour petroleum with a mercapt number below 10, the catalyst should contain 8 to 40 percent by weight of water and with a mercapt number below 80 it should contain about 20 percent by weight of water.

The values obtained at 43% water content already show a significant deterioration in the initial color of the treated oil and, in the case of the starting oil with a very high mercapt number, also an unsatisfactory one Color after aging.

Influence of the copper content

It also increased the sweetening power of the catalyst

determined with constant total water content and different weight ratio of clay to copper sulphate. It

could not have a noticeable influence on the sweetening power of the catalyst in the range between the Clay to copper sulphate ratios of 12: 1 and 3: 1 can be found. If the ratio is greater than 12: 1, then the copper content is so low that the treatment time required to achieve a sweetened end product becomes inexpediently long. But if the ratio is less than 3: 1, the end product will be sweetened received, but there are other disadvantages such. B. poor color of the treated product.

Comparison with the cuprichloride process

For comparison purposes, the three acid oils already used above were treated with cupric chloride catalyst (72 percent by weight clay, 20 percent by weight * 5 water, 8 percent by weight CuCl ₂ at the usual temperature of 46 ° C.

oil Color of
at first treated oil
aged Midcontinent oil 19th _ 2 West Texas Crude Oil
Pre-treated with acid
West Texas Oil - 4th
0 4 NPA *)
2 NPA Pre-treated with acid
West Texas Oil **) - 12

*) A sediment formed.
**) Treated at 104 ° C.

In all cases a sweetened oil was obtained, however in no case did the cuprichloride process provide a sweetened oil with satisfactory color stability. at the high-mercaptan sulfur-containing West Texas oil, the distillate of which has a color value before treatment of about 20, the color deteriorated through the treatment to below the sufficient Value of 10 Saybolt.

In practice, the acidic oil 10 to be treated, supplied according to the schematic drawing, should be free of hydrogen sulfide or caustic alkalis. If it contains hydrogen sulfide, this can be removed by simply washing it out with caustic alkalis. The fed oil is passed through a rock salt filter 11 to remove any traces of alkali left in the washed oil. From the salt filter 11, the oil passes through the line 12 to the heater 15, in which its temperature is increased to 88 to HO ⁰ C, preferably to 93 ⁰ C ₁ . It has been found that hot oil removes the water from the catalyst, which is quickly deactivated, and that this harmful effect, if not completely suppressed, can be largely prevented if the hot oil is used before it is used with the catalyst comes into contact, saturates with water. Water (from a source not shown) is sent by means of a metering pump 17 through line 18 into the heater 19, where it is heated to about 93 ° C. The hot water then passes through line 20 into line 16 where it enters the flowing hot oil. Only as much water is added as is necessary to saturate the hot oil. Commercially available oxygen or air is introduced through line 22 into the hot oil stream saturated with water. The amount of oxygen to be added depends on the mercaptan content of the acidic oil. For every 0.01 ° / ₀ mercaptan about 1.87 liters of oxygen per hectolitre acidic oil required. The combined stream then enters mixer 25 where the oxygen is finely divided in the hot oil and any water droplets are broken up and dissolved in the hot oil. The water-saturated, oxygen-rich, hot oil then flows through line 26 to pump 27 and then into line 30.

In the slurry tank 32, the catalyst fed in via path 33, which essentially consists of 60 to 75 weight percent inert adsorbent, 5 to 20 weight percent copper salt and 20 weight percent Water, preferably from 72 percent by weight fuller's earth, 8 percent by weight copper sulfate and 20 percent by weight Water, with hot oil supplied from line 16 through line 34 into a pumpable Transformed into slurry. The pump 36 drives this catalyst-oil slurry through line 37 into the Line 30 in which the catalyst enters the stream of hot, acidic oil. The hot oil-catalyst mixture passes through line 40 into the reaction vessel 41, a vessel provided with a conical bottom, in which the catalyst settles out of the sweetened (or not yet completely sweet) oil. The catalyst is then discharged from the reaction vessel 41 through line 42 and can via valve 43 through line 44 removed from the system as exhausted. The oil is drained from reaction vessel 41 through line 47. Through feed line 48, water is fed into line 47 and the water-oil stream thus created mixed in mixer 50. The purpose of this water addition is to remove those suspended in the sweetened oil Particles of copper sulphate and fuller's earth. The amount of water to be used for this can be 25 to 100 parts by volume for every 100 parts by volume of oil; preferably about 50 parts by volume are used. From mixer 50 the water-oil mixture passes through line 51 into the settling tank 52. This becomes the washing water diverted away through line 53 into the sewer, but it can optionally also into line 48 or to the pump 17 are returned. The washed oil leaves the settling tank 52 through line 55 and flows through the cooler 56, where it is cooled to the temperature of the surroundings, and then through the salt filter 58 for drying. The oil leaving the salt filter passes through line 59 as the end product into the storage tank (not shown).

It has been observed that acidic oils with a mercapto number greater than 10 even then quickly remove the catalyst Ineffective if the oil theoretically contains enough oxygen to regenerate the catalyst. It is believed that the deactivation is primarily a consequence of the dehydration of the catalyst through the hot oil is. This effect can be achieved to some extent by saturating the hot oil with water the collision of the oil with the catalyst can be suppressed. The catalyst can also be used as such can be regenerated by adding water to the exhausted catalyst oil sludge and the slurry treated with oxygen. These measures can reduce the usability of the catalyst extended and this can be returned to the cycle. So if the oil to be treated can be a West Texas fuel oil distillate having a mercapto number of 70 is closed, valve 43 is closed and the catalyst is off The bottom of the reaction vessel 41 can be drained into the valved line 62. The amount of water which is necessary to bring the catalyst to the desired water content, preferably 20 percent by weight, is brought through heater 64, where it is heated to about 93 ° C, and line 65 in line 62 sent. Oxygen is also introduced into line 62 through line 67. Those of free oxygen, water, The slurry made up of the catalyst and oil then enters the mixer 68, where the reactivation takes place

End is performed. The regenerated catalyst passes through line 70 in the admixer 71, which is in one with Valve provided bypass line to line 40 is located. The admixer 71 causes the flow through the Line 62, mixer 68 and line 70. The flow from line 70 mixes with the hot, acid oil and the product from slurry tank 32. The mixture then enters line 40 and through this into the reaction vessel 41.

If an oil of satisfactory color fastness is obtained from the acidic oil without washing it out with water can be, the washing can also be omitted and the oil from the reaction vessel 41 directly by line 75 and line 55 are sent to the cooler.

Further modifications and other procedural measures are apparent to those skilled in the art from the above description readily apparent.

Claims (9)

Patent claims: 1. A method for sweetening mercaptan-containing hydrocarbon oils, in which the oil is brought in the liquid state in the presence of free oxygen with a catalyst in intimate contact, which consists essentially of an inert adsorbent, a copper salt and water, characterized in that the treatment between 88 and 110 ⁰ C is carried out, the catalyst contains at least 8 percent by weight of water and the copper salt is copper sulfate and / or a preferably water-soluble copper sulfonate. 2. The method according to claim 1, characterized in that a catalyst is used in the essentially from 8 to 45 percent by weight water and from the inert adsorbent and the Copper salt in a weight ratio of 12: 1 to 3: 1. 3. The method according to claim 1 or 2, characterized in that the treatment temperature is ^{between 93 and 104 0C.} 4. The method according to claim 1 to 3 for sweetening sour petroleum with a mercapt number below 10, characterized in that the catalyst used contains 8 to 40 percent by weight of water. 5. The method according to claim 1 to 3 for sweetening an acidic petroleum with a mercapt number below 80, characterized in that the catalyst used contains about 20 weight percent water. 6. The method according to any one of the preceding claims, characterized in that a catalyst is used which consists essentially of 60 to 75 percent by weight inert adsorbent (e.g. 72 percent by weight fuller's earth), 5 to 20 percent by weight copper salt and 20 percent by weight Water exists. 7. The method according to any one of claims 1 to 6, characterized in that the copper salt is copper sulfate, a copper alkyl sulfonate containing no more than 10 carbon atoms per molecule or no more than 8 carbon atoms in the alkyl substituents containing copper aryl sulfonate, e.g. B. copper toluenesulfonate. 8. The method according to any one of claims 1 to 7, characterized in that the copper salt is prepared from a mixture of methane, ethane and butanesulphonic acid or an alkylsulphonic acid mixture consisting of methane, ethane, propane and butanesulphonic acid. 9. The method according to any one of the preceding claims, characterized in that the sweetened oil is separated from the catalyst and washed with water. Considered publications:
U.S. Patent Nos. 2,094,485, 2,042,053;
Ellis, The Chemistry of Petroleum Derivatives, 1937, Vol. II, p. 477; Kalichevsky and Stagner, Chemical Refining of Petroleum, New York, 1942, p. 255. 1 sheet of drawings © 80S 580/530 7.