RU2478687C1 - Commercial oil treatment composition - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to oil industry and can be used for neutralisation of hydrogen sulphide and methyl and ethyl mercaptans in commercial oil during oil treatment and in oil products (fuel oils). The invention deals with composition for neutralisation of hydrogen sulphide and methyl and ethyl mercaptans in commercial oil based on hemiformal mixed with aromatic hydrocarbon, which contains one of the following compounds as aromatic hydrocarbon in quantity of up to 30 wt %: benzene, toluene, xylenes, diethyl benzenes.

EFFECT: increasing reaction speed at reduction of toxicity and cheapening of the composition.

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Description

The invention relates to the oil industry and can be used to neutralize hydrogen sulfide and methyl and ethyl mercaptans in commercial oil in the process of preparing oil and in petroleum products (fuel oils).

Various compositions of hydrogen sulfide neutralizers and mercaptans in oil are known. For example, based on salts of dicarboxylic acids (adipic, succinic, glutaric, etc.) (application No. 2003129715/15), based on various amines (applications 2002120783/04, 99104020/04, 2000128403/03, patents RU No. 2160761, No. 2107085, No. 2141482, No. 2196114), nitrite salts, for example NaNO ₂ (application No. 2003116365/04). A common drawback of these reagents is that the reaction products precipitate and form mechanical impurities insoluble in oil, the so-called ballast.

From patent RU No. 2348679 the composition of a hydrogen sulfide neutralizer and mercaptans based on hemiformal is known. Laboratory tests (Table 1) show that the reaction rate of hemiformal with hydrogen sulfide is low for real use as a neutralizer in oil treatment systems. The complete neutralization reaction at T = 40 ° C takes about 48 hours (dosage 150 g / t).

Tab. one Name of analysis Change in hydrogen sulfide concentration 6 o'clock 24 hours 48 hours The initial content of hydrogen sulfide 72 ppm 48.7 33.5 5.5

The low reaction rate of hemiformal with hydrogen sulfide in oil is due to the fact that hemiformal is a hydrophilic substance, and oil is hydrophobic, they are not soluble in each other.

It is also known that the effectiveness of neutralizers is often necessary to increase.

One way is to add catalysts. So, from the patent RU No. 2348679, the composition of a hydrogen sulfide neutralizer and mercaptans based on hemiformal is known, in which hydrocarbon nitro compounds are also added as a catalyst to increase the efficiency of the neutralization process. On the one hand, hemiformal is a neutralizer of hydrogen sulfide and mercaptans, which forms oil-soluble compounds as a result of reactions, on the other hand, hemiformal is characterized by low solubility in oil, and the reaction rate is increased due to the presence of a catalyst. However, dilution of hemiformal with nitro compounds (for example, nitrobenzene) has a number of significant drawbacks, including high toxicity and high cost of nitro compounds.

Another option is to dilute the base compounds of the converter. The closest analogue is the neutralizer according to patent RU No. 2349627, in which the amino esters of the general formula: (R-) nN (-CH2-OR ′) m, where R is alkyl, isoalkyl, hydroxyalkyl C1-C14 or cyclohexyl or benzyl, or a divalent group of the formula —CH2 — O — CH2 — CH2—, connected to the nitrogen atom of the amino ester to form a five membered heterocyclic ring; R ′ is alkyl, isoalkyl or alkenyl, preferably C1-C4; n is 1 or 2; m = 3-n, diluted with an organic solvent, preferably from aromatic hydrocarbons, for example toluene, ethylbenzene, butylbenzene, polyalkylbenzene fraction or solvent type "Nefras". The solvent is used to reduce viscosity, pour point. The disadvantage of the analogue is that the products of its reactions are toxic and form a mechanical precipitate in the oil.

The aim of the invention is to increase the efficiency of the catalyst for hydrogen sulfide and mercaptans based on hemiformal.

The goal is achieved by adding up to 30 wt.% Aromatic hydrocarbons (toluene, xylenes, diethylbenzenes, benzene) to hemiformal. By adding aromatic hydrocarbons, the solubility of hemiformal in oil increases, which leads to an acceleration of the reaction of hemiformal with hydrogen sulfide and mercaptans, and an increase in the penetrating ability of the neutralizer. At the same time, there are no products insoluble in oil in the oil, the neutralizer eliminates toxic and expensive catalysts.

As a result of the application of the proposed converter, the spent process of preparing commercial oil is not disturbed, the construction of special plants is not required, the cost of the converter itself is low.

The implementation of the invention

Hemiformal is obtained as a product of the interaction of paraformaldehyde and methanol (L.V. Kogan. ZhPKh, No. 12, 1979, "The study of the state of aqueous-methanol solutions of formaldehyde by NMR", p. 2730).

The reaction of hemiformal with hydrogen sulfide is similar to the reaction of formaldehyde with hydrogen sulfide (02.00.13 - Petrochemistry / Gafiatullin Rigat Rukhovich / - Ufa, 2000.- 21 p., Ill., Table. - Bibliography: p.19-20 (11 titles) .- b / c. "Development of environmental and resource-saving processes for processing hydrogen sulfide", p. 7); the reaction product is substances that are soluble in oil, actually turning into part of the oil.

The reaction with hydrogen sulfide

Reactions with methyl and ethyl mercaptans

IV. By mat. the balance of reactions (I-III) 1 ppm of gemiformal neutralizes:

Hydrogen sulfide - 62: 34 = 0.548 ppm

Methyl mercaptans - 62: 48 = 0.774 ppm,

Ethyl mercaptans - 62: 62 = 1.000 ppm.

Ballast in oil with this form of a neutralizing agent - a hemiformal solution is not formed.

For the industrial neutralization of hydrogen sulfide and light mercaptans in crude oil, the following composition is used.

Tab. 2 Composition of a hydrogen sulfide neutralizing agent and light mercaptans with a shortened neutralization reaction time Name The formaldehyde content *,% by weight The content of aromatic hydrocarbons,% by weight The methanol content,% by weight The reaction time in the oil stream, hour Reagent Composition up to 57.5 up to 30 from 37.5 up to 1

As an aromatic hydrocarbon, one of the following compounds is taken: benzene, toluene, dialkylbenzenes (including xylenes), KORB (distillation residue of benzene rectification).

Thus, the patented composition of the hydrogen sulfide neutralizer has a high reaction rate and low consumption coefficient (the number of grams of the reagent required to neutralize 1 gram of hydrogen sulfide and light mercaptans), for example, in comparison with the popular compounds for the neutralization of hydrogen sulfide - amino esters (patent No. 2349627, application 2005134035 / 04), and also does not contain toxic and expensive nitro compounds (Table 3). Table 3 shows the results of laboratory tests of the neutralizers. In relation to the patented composition, experiments were carried out with toluene, benzene, xylene and KORB, the values of the parameters of table 3 for which did not differ within the experimental error.

Table 3 The effectiveness of various hydrogen sulfide and light mercaptan neutralizers in marketable oil in comparison with the patented composition is a mixture of hemiformal with an aromatic hydrocarbon (benzene, toluene, dialkylbenzenes, etc.) Reagent Composition Expense ratio Reaction time Aminoesters 3-6 At least 3 hours Gemiformal 2-3 At least 6 hours Hemiformal + nitrobenzene (in the ratio of 75/25 by weight) 2-3 Not less than half an hour Gemiformal + toluene (in the ratio of 70/30 by weight) 2-3 About an hour Hemiformal + dialkylbenzenes (70/30 by weight) 2-3 About an hour Hemiformal + diethylbenzenes (70/30 by weight) 2-3 About an hour Gemiformal + xylene (in the ratio of 70/30 by weight) 2-3 About an hour

As can be seen from the table data, the addition of aromatic hydrocarbons to the hemiformal significantly increases the rate of neutralization of hydrogen sulfide by hemiformal (the reaction rate decreases by six times). The patented composition is practically not inferior in the rate of neutralization of the hemiformal mixture with nitro compounds (patent No. 2348679, application 2005106566/04), but has undeniable environmental advantages (nitro compounds are usually very toxic; nitrobenzene is “blood poison”) and economically (aromatic hydrocarbons are readily available and cheap).

Claims (1)

Composition for neutralizing hydrogen sulfide and methyl- and ethyl mercaptans in salable oil based on a mixture of hemiformal with an aromatic hydrocarbon, containing as aromatic hydrocarbon in an amount up to 30 wt.% One of the following compounds: benzene, toluene, xylenes, diethylbenzenes.