DE1545302A1 - Process for reducing the mercaptan content of petroleum hydrocarbons - Google Patents

Description

Process to reduce mercaptan levels of Brdttlkohlenwaesermtoffen

for the registration the priority tob April 22, 1964 from the U3A ~ P4vtentan «eldung Serial Io 361 879 is claimed.

»En ·

The invention relates to a method sua reducing the Mereaptane content of coal water, which is particularly suitable for the treatment of oil-based hydrocarbons. That Processes can therefore be used, including the meroaptan content the Tersohiedensten raw material β, such as liquefied Brdölgase. acidic light gasoline (such as split acidic light gasoline, acidic mineral oil, directly divided gasoline or Gealeohe dereelben), heavy gasoline, solvents, DUeentreibetoffe, Iieuehtule and Heleöle.

Ärdölkohlenwaaeeretoffe often contain elementary substances Sulfur and sulfur compounds such as hydrogen sulfide. Mercaptans, organic sulfides and disulfides · Ia in general

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are sulfur compounds in petroleum hydrocarbons! * undesirable. " ^{Petroleum hydrocarbons 11} are understood here as well as distillates such as light petrol, Sehwerbenzine, Leuhtoils, jet fuels and heating oils, which are obtained from petroleum, as well as liquefied petroleum gases and natural bones which are obtained from natural gas sources. Of the sulfur compounds contained in petroleum hydrocarbons Hydrogen sulphide and mercaptans are particularly undesirable because they give the petroleum hydrocarbons an unpleasant odor even in very low concentrations. In addition, the petroleum hydrocarbons are often corrosive due to the contents of hydrogen sulphide and meroaptans, which leads to difficulties in their handling and storage. Hydrogen sulphide can easily be removed by washing with alkali Some lower-boiling mercaptans can also be extracted relatively easily by alkali washing. However, higher-boiling keroaptans cannot easily be extracted by alkali washing, because the mercaptans are so acidic d, whose aoidity decreases with increasing molecular weight. The mercaptans can often be removed from very light petroleum hydrocarbons, such as liquefied petroleum gases, in a satisfactory manner by simple alkali washing, because these hydrocarbons contain only very light mercaptans. In the case of somewhat higher boiling hydrocarbons, such as light gasoline, the removal of the mercaptans by alkali water is only possible to a limited extent, even if they are carried out in the presence of dissolving agents.

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leads (so-called "SoIutleer method"; TgI * Zerbe, Mineral oils and related products, 1952, page 320). Because of the difficulty in removing the mercaptans, they will often converted into disulfides by the so-called sweetening process, which are relatively odorless. Geaäae is used in petroleum products to denote ale "sties" when it denotes the Dootor-Teet is enough. This test is against heroaptan sulfur or hydrogen sulfide in concentrations of 5 to 10 ppa sensitive.

The Doctor-Teet is carried out as follows The sample is shaken into a test tube with sodium plumbite solution. If it contains hydrogen sulfide, sohwar-Ees solid PbS precipitates. If no PbS fails, the present becomes determined by mercaptans by adding a pinch of "sulfur flowers" and shaking. If mercaptans are present, it falls here PbS off. The reagent solutions and recommended procedures are detailed in "UOP Laboratory Test Methods for Petroleum and its Products "4th Edition, published 1959t by D.P. Johnson, Jr., Yerlag Universal Oil Products Company, Des PlaineSr Illinois, described.

The horns for many petroleum products are mandated to be sweet, as determined by the Doctor's test. Under certain circumstances, however, it is sufficient to just make petroleum products "sweet-smelling". This can be achieved by reducing the hydrogen sulfide and mercaptan sulfur content to 20 to 50 ppm. So while it is comparatively easy

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according to the process described here petroleum hydrocarbons so far ssu fines that they qualify for the Dootor test, it is also possible to terminate the sweetening reaction in any intermediate stage. In such a case one does not get one naoh the doctor test as "sweet" found product, but the Mereaptan content is significantly reduced.

The invention relates to a method for sweetening petroleum hydrocarbons. According to the process according to the invention, petroleum hydrocarbons with molecular oxygen in the presence of catalytic! Amounts of one or more oxides of nitrogen, namely NO, NO ₂ , HgO ^, N ₃ O ₄ and / or N ₂ O ^, treated. This treatment converts the mercaptans into disulphides. The process can be carried out on its own in which the mercaptans initially contained in the petroleum hydrocarbons are converted into disulphides. The process can also be carried out in combination with an alkali wash. In the latter case, only the meroaptans that cannot be extracted by the alkali are converted into disulfides, and the total sulfur content of the petroleum hydrocarbons is reduced.

As already mentioned, the invention relates to a Method of matching petroleum hydrocarbons to the Doctor's test. Thus, light petrol with the characteristics given below, which contain about 0.0005 to 0.50 wt.% Meroaptan sulfur, can be used according to the method according to the invention be treated:

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Specific gravity, 16 ° / 16 ° C 0.61 to 0.89

Reid vapor pressure, kg / cm ² abs. 0.35 to 1.05 distillation

Onset of boiling, ⁰ C 29 to 60

End of boiling point, ⁰ C 171 to 221

luminous oils with the following characteristics that may contain about 0.0005 to 0.50 wt .- # Hercaptan sulfur being treated according to the method according to the invention

Specific gravity, 16 ° / 16 ° C 0.779 to 0.876

distillation

Beginning of boiling, ° 0 121 to 260

Boiling end, ⁰ O 232 to 399

The method according to the invention is relatively simple, since it requires nothing more than the bringing together of the aromatic hydrocarbons, the molecular oxygen and a catalytic amount of an oxydea of nitrogen. Of the molecular oxygen can be satisfactorily applied in the form of air · the oxide of nitrogen is extremely soluble in petroleum hydrocarbons, which is due to the molecular oxygen does not apply. Therefore, in the treatment, the molecular oxygen and the oxide of nitrogen are used introduced into the petroleum hydrocarbons while the latter are kept in violent motion. In this way an effective contact between the mercaptans in the petroleum hydrocarbons ^ the oxygen and the oxide of nitrogen

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Substance reached, whereby disulfides are formed.

The amount of molecular oxygen to be used in the process according to the invention is at least the amount required to oxidize the mercaptans to disulfides stoichiometrically. Since theoretically 4 moles of mercaptan react with 1 mole of molecular oxygen to form 2 moles of disulfide and 2 moles of water, nan needs at least 0.25 moles of molecular oxygen per mole of the mercaptans contained in the light petroleum distillate to be treated. In other words, if the required amount of solar oxygen is related to the amount of petroleum hydrocarbons to be treated, the stoichiometrically required amount of molecular oxygen is about 0.000125 to 0.125 wt .- # Usually supply oxygen in large excess ¹ . However, it will seldom be advantageous to use more than about 2 to 5% by weight of molecular oxygen, based on the petroleum hydrocarbons to be treated. The amount of nitrogen oxide required, based on the petroleum hydrocarbons to be treated, is at least about 0.000005% by weight, preferably about 0.000025 to 0.25% by weight.

Temperature and pressure are not decisive in the process according to the invention; preferably one works at about room temperature and atmospheric pressure. Although higher temperatures increase the rate of reaction between would lead to the meroaptans and molecular oxygen, this advantage is compensated for by the fact that the molecular

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Cular oxygen more easily escaped from the at higher temperatures Reaction seone escapes. In general, temperatures can range from -1 to 4-66 ° C, preferably from about +10 to 4-32 ° 0, work. The bridge does not affect the reaction rate in any noteworthy Auenasse, if nan disregards the fact that increased pressure introduces the molecular Oxygen «facilitated in the bromohydrocarbons. Ib In general, the process can be carried out at pressures from about 0 to 70 atmospheres, preferably from about 0 to 3-5 atmospheres. You can also work with prevented pressure! however, this does not offer any particular portion of the gate.

The heat resistance depends both on the meroaptana tightness contained in the hydrocarbons to be treated as well as the concentration of the nitrogen oxide used as a catalyst. At very low catalyst concentrations, the conversion of substantial amounts of meroaptans into disulfides can take several days. With high catalyst concentrations, it only takes 30 minutes last. In general one becomes a catalyst concentration where a sweet product is obtained in 30 minutes to 4 hours. The reaction time can therefore be about 5 minutes to 10 days »preferably about 10 minutes to 1 day, in particular about 30 minutes to 4 hours.

Your reaction is easy to stall by the introduction of the molecular "oxygen" into the Petroleum hydrocarbons interrupts and the hydrocarbons

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lets stand without further movement; nan can do the implementation but also carry out until the complete course, in which case they disappear by themselves if the mercaptans ceases to remove excess dissolved oxides dee nitrogen from the petroleum hydrocarbons after the end of the implementation remove, the hydrocarbons can be passed over alkaline substances such as lime, sodium hydroxide, etc. Excess oxides of the nitrogen can also be removed by pouring over the treated petroleum hydrocarbons Adsorbents such as activated carbon, clay, silica gel, aluminum oxide, etc., conducts.

Am old a 3-liter flask equipped with a magnetic stirrer is charged with 600 ml (412.2 g) laturbenein, which has the following characteristics

Specific weight, 16 ° / 16 ° 0 0.7405

Held vapor pressure (method D323), kg / cm ² abs. 0.57

Hydrocarbon analysis Aromatics, v / v 4.0

Olefins, YoI .- * 0.5

saturated hydrocarbons, 95.5 vol

Distillation (method D 86) Beginning of boiling, ⁰ O 42

50 jC-DeBtlllatpunkt, ⁰ C 61

95 Jt distillate point, ⁰ C 102

End of boiling, ⁰ C 121

Water content, wt. - $> 0.0252

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Over the course of 5 minutes, a total of 0.075 g of NO ₂ and 0.20 g of oxygen are added. It is found here that the HO ₂ largely dissolves in the gasoline. The magnetic stirrer is activated and the reaction is continued for 1/2 hour at 27 ° 0 and 0.35 atm. The product is then examined by doctor-teat.

Example 2

Example 1 is used with 407.0 g of the same gasoline and 0.030 g of NO ₂ with a reaction time of 2 hours. Every half hour, a sample of the product is examined by the poctor test.

Example 3

! fan works, as described above, with 410.7 g of the same Gasoline, but only 0.020 g NOg «within the first For four hours, a sample is taken every half hour and examined by the Doctor test. After another 16 hours it will Again a sample is taken and analyzed by the Doctor-Test,

The reaction mixture is then left to stand for 10 days «,

Example 4

In Examples 1 to 3 was the invention Sweetening process in a glass flask with normal room lighting performed “To see if the light is for the Initiation of the reaction plays an important role, the procedure of Example 2 is followed by shielding the flask against each lighting repeated. In this implementation, the KoI-ben completely enclosed in aluminum foil. Here

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the gasoline won't eüaa in 2 hours; in 2 1/2 hours ee but duroh Doctor-fest as sues. The SUeeung So in the absence of light runs only a little more slowly, from which it can be concluded that the light is the Implementation is somewhat accelerated, dea according to the invention is not necessary.

Example 5

In order to explain the applicability of the process to other hydrocarbons see below, 600 al (478.7 g) of a Luminous oils8 from a site Ib Ordovicium, which includes the following Characteristic values «

Specific gravity, 16 ° / 16 ° 0 0.7923

Carbon dioxide analysis
(Method D1319)

Aromatics, V0I.-9 & 10.5

Olefins, vol ~ # 1.0

Saturated Hydrocarbons, Vol - £ 88.5

Distillation (method D86)

Onset of boiling, ⁰ C 183

£ 50 distillate point, ⁰ O 224

95 ^ distillate point, ⁰ O 262

End of boiling point, ° 0 272

Water content, wt .- ^ 0.0145

According to Example 1 to 3, _{treated with 0.040 g HO 2} and 0.20 g molecular oxygen. In this case, a product found to be sweet according to the doctor's test is obtained within 1/2 hour. The results of Examples 1 to 4 are summarized in Table I, those of Example 5 in Table II.

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Iabslls I

Total sohwsfti, wt .- * Meroaptaneohwsfsl, wt .- * Disulfidesohwsfsi, wt .- *

Starting well

0.088 0.045 0.007

Elemental Sohwefsi, wt .- * <0.0005 Hydrogen sulfide, weight * <0.001 Applied Consumed g, ^ Doctor-Teat eauer

Approximate duration the Suez

Product of the BtI game 1

0.083 <0.00005

0.05 <0.0005 <0.001

0.0186

0.01125

1/2 hour 2 hours «

Product of example 2

0.079 <0 _t 00005

0.052 <P, 0005

0.0074 0.01125

Product Product ds · Bside example ^ game 4

0.082 0.083

<0.00005 <0.00005

0.052 0.055

<0.0005 <0.0005

0.0049 0.0074 0.01125 0.01125

etiee stabbed

10 fags 2 1/2 hours

CO O K>

Table II

Total sulfur, weight Meroaptaneohwe fei, weight -φ disulfide sulfur, weight * -Jt elemental sulfur, weight applied NO ₂ , weight consumed O ₂ * weight doctor test

Approximate duration of the sweetness

Starting good

0.060

0.027

0.003

<0.0005

angry

Product dee example 5

0.051 0.00044 0.021 <0.0005 0.0084 0.00665 sweet

1/2 hour

To determine whether the treated petroleum hydrocarbons are eÜBB, the doctor test is used. The lower-level process proves to be extremely effective for the conversion of mercaptans into disulfides. The total sulfur content of the petroleum hydrocarbons does not change significantly as a result of the treatment, and the other sulfur compounds are also not influenced, as far as this can be determined. Furthermore, it can be seen that the HO _{2 used} actually acts as a catalyst and not as a reaction participant, even assuming that the NO ₂ decomposes completely during the reaction to form atomic or molecular oxygen, the amount of in the NO ₂ in chemical bond to the nitrogen sur the oxygen available in Examples 2, 3 and 4 would not be sufficient to the

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To convert mercaptans into disulfides. ' Although the remaining Sulfur compounds have not been identified, their presence is not harmful in the present context, since the treated petroleum hydrocarbons pass the Doctor's test.

The method according to the invention is also based on a different one Point of view remarkable. As mentioned above, when the mercaptans are converted into disulfides, water is formed. Furthermore, tnt ~ holds both the gasoline and the luminous oil in front of the dtr Sweetening small amounts of water. These amounts of water are awar small compared to the amount of petroleum hydrocarbons **; however, the amount of water that forms is proportionate large in comparison to the amount of them that are formed. Disulfides. It could therefore have been expected that The presence of this water could also have formed sulfonic acids. Sulphonic acids are extreme in petroleum hydrocarbons undesirable because they are highly corrosive. In fact, however, the formation of sulfonic acids could not be detected will.

With regard to the above-described use of NO ₂ in the process according to the invention, it should be pointed out that at atmospheric pressure there is an equilibrium between NOg and N ₂ O ₂ within a relatively large temperature range (approximately from -11 ° 0 to + 140 ° 0). At low temperatures, the NO ₂ turns into NgO ^, a honey-colored liquid. At higher temperatures, the NgO ^ changes to NO ₂ , a red-brown gas. Therefore, when talking _{about NO 2 here,}

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this also refers to NgO ^, if such conditions exist, under which eich NgO ^, forms.

The process according to the invention offers various advantages over the sweetening processes frequently used in der.Technik. Since the nitrogen oxide used as a catalyst in the process is extremely soluble in petroleum hydrocarbons, an intimate contact only needs to be established between two phases, namely the petroleum hydrocarbons (which contain the catalyst in solution) and the oxygen-containing gas, such as air. In many other methods, for example in the Kupferohlorid-SUssung, wherein the air-Inhlbitor-sweetening or when ⁿ air ⁿ solutizer -SUesung must three phases are brought into close contact with the third phase, either a solid catalyst or a is a liquid that cannot be mixed with the hydrocarbon phase, such as alkali lye. The process according to the invention can also be carried out at low temperatures, for example at 21 to 27 ° C., while some other processes require higher temperatures. For example, the sweetening according to the doctor process is usually carried out at 66 ° C, while the catalytic hydrogenative desulphurisation of hydrocarbons even requires temperatures of 204 to 316 ° C. Finally, the catalyst used is also relatively cheap, and it only needs to be used in very low concentrations. Therefore, the recovery and reuse of the catalyst is possible, but not necessary from an economic point of view.

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Claims (1)

Claims Λ J Process for reducing the mercaptan content of petroleum hydrocarbons, characterized in that the hydrocarbons are used in the presence of catalytic amounts of one or more oxides of nitrogen, namely NO, HO ₂ * N ₂ O ₅ , N ₂ O ₄ and / or N ₂ Oe * treated with molecular oxygen. 2. The method according to claim 1, characterized in that Mineral spirits are treated with molecular oxygen in the presence of catalytic amounts of nitrogen oxide, 3 * Method according to claim 1, characterized in that " Leuohtöl in the presence of catalytic amounts of the oxide des Nitrogen is treated with molecular oxygen. 4. The method according to claim 1 for reducing the Meroaptanehaltes of petroleum hydrocarbons ^ containing about 0.0005 to 0.50 wt .- # mercaptan sulfur, characterized in that the hydrocarbons in the presence of at least about 0.000005 wt .- ^ of the oxide des Nitrogen be treated with at least about 0.000125 wt. -4> molecular oxygen. ^ * 5. The method according to claim 2 for reducing the meroaptan content of light gasoline, which is about 0.0005 to 0.50 wt * - # Contains mercaptan sulfur, characterized in that the light gasoline in the presence of at least about 0.000005 GeWo-56 of the oxide of nitrogen with at least about 0.000125 wt .- # molecular oxygen is treated. - 15 -909825/1288 βρ Method according to claim 3 for preventing the mercaptan content of luminous oil, which is about 0.0005 Ms 0.50 wt .- ^ Contains mercaptan sulfur, characterized in that the Luminous oil in the presence of at least about 0.000005 wt. ■ => # des Oxides of nitrogen with at least about 0.000125 wt% molecular Oxygen is treated. 7. The method according to claim 4 to 6, characterized in that the hydrocarbons are treated with molecular oxygen _{in the presence of at least about 0.000005 wt .- # NO 2.} 8. The method according to claim 7, characterized in that the hydrocarbons in the presence of about 0.000005 to 0.25 Wt .- # NO2 at a temperature of about -1 to + 66 ° C and a pressure of about 0 to 70 atmospheres with about 0.000125 to 0.125 Gewο-56 molecular oxygen. - 16 909825/1288