NEUTRALIZATION OF HYDROGEN SULFIDE AND LIGHT MERCAPTANES IN HYDROCARBON MEDIA

Abstract

Disclosed is a composition and method for neutralization of hydrogen sulfide and light mercaptanes from hydrocarbon media, and improvement of the copper strip indicator in petroleum products. The composition is an aqueous solution of polysulfides comprising alkali metals and/or polysulfides of primary or secondary ethanolamines, alkali metal hydroxides, water-soluble alkylamines and optionally alkali metal nitrites.

Claims

1. A composition for neutralization of hydrogen sulfide and light mercaptans from hydrocarbon media, the composition comprising: 3-15% by weight of polysulfides of alkali metals and/or polysulfides of primary or secondary ethanolamines, 5-35% by weight of alkali metal hydroxides, 2-7% by weight of water soluble alkylamines, and water.

2. The composition according to claim 1, further comprising 5-35% weight of an alkali metal nitrite.

3. The composition according to claim 1, wherein the alkali metal hydroxide is selected from contains sodium hydroxide and/or potassium hydroxide.

4. The composition according to claim 1, wherein the water-soluble alkylamines is selected from alkanolamines and/or diamines.

5. The composition according to claim 2, wherein the alkali metal nitrite comprises sodium nitrite.

6. The composition according to claim 4, wherein the alkanolamine comprises one or more primary, secondary or tertiary ethanolamine.

Description

DETAILED DESCRIPTION

[0019] In the composition for neutralization of hydrogen sulfide and light mercaptanes and hydrocarbon media, and improvement of the copper strip indicator in petroleum products containing a composition of an aqueous solution consisting of alkali metal compounds and agents containing the amino group, according to the invention, in the capacity of alkali metal compounds, the composition includes polysulfides of alkali metals and/or polysulfides of primary or secondary ethanolamines, alkali metal hydroxides, while in the capacity of agents containing the amino group, it contains water-soluble alkylamines with the following ratio of components:

[0020] polysulfides of alkali metals and/or polysulfides of primary or secondary ethanolamines of 3-15% by weight,

[0021] alkali metal hydroxides 5-35% by weight,

[0022] water soluble alkylamines 2-7% by weight,

[0023] water—the remainder.

[0024] The composition may additionally contain alkali metal nitrite in an amount of 5-35% by weight.

[0025] The composition in the capacity of alkali metal hydroxides may contain sodium or potassium hydroxides.

[0026] In its capacity as water-soluble alkylamines, the composition may contain alkanolamines and/or diamines.

[0027] In its capacity of alkali metal nitrite, the composition may contain sodium nitrite.

[0028] In its capacity of alkanolamines, the composition may contain primary, secondary or tertiary ethanolamines.

[0029] The neutralizer indicated may be applied by the reagent method (introduction into the raw material flow) jointly with any appropriate PAV known from the prior art (sulfonol, neonol, OP-10, aminoxide etc.) for improvement of the dispersion capacity in the petroleum media, or without PAV. The neutralizer may be jointly utilized with organic polar solvents known from prior art, which improve the transition of mercaptanes to the polar phase (methanol, isopropanol, glycols and their ethers, etc.) or without solvents.

[0030] The component for neutralization of hydrogen sulfide and mercaptanes is prepared by simply dissolving the components in water or mixing of their aqueous solutions under normal conditions at room temperature.

[0031] The problem posed is solved in that the neutralizer consists of an aqueous solution of the following components with content in weight %:

TABLE-US-00001 TABLE 1 Polysulfides of alkali metals and/or ethylamines 3-15% (primary or secondary) Aliphatic amines  2-7% Inorganic base 5-35% Water remainder

[0032] If the raw material is processed with a high hydrogen sulfide and mercaptane content, to reduce the processing time it is appropriate to introduce alkali metal nitrite into the composition of the solution, as an oxidant, with content in weight %:

TABLE-US-00002 TABLE 2 Polysulfides of alkali metals and/or ethylamines 3-15% (primary or secondary) Aliphatic amines  2-7% Inorganic base 5-35% Alkali metal nitrite 5-35% Water remainder

[0033] With this, any alternative reagent may be used for purposes of purification of raw material containing only hydrogen sulfide or only mercaptanes, and for purification of raw material that contains hydrogen sulfide and mercaptanes.

[0034] In the capacity of water-soluble aliphatic amines, preferably alkanolamines are used, preferably ethanolamines and/or diamines.

[0035] Amine polysulfides and alkali metal polysulfides used in this invention are water-soluble compounds containing a simple (non-branched) chain of sulfur atoms Sn.sup.2−, where n=2, 3, 4, 5 or 6. With this, the most widespread and stable compounds are deemed to be polysulfides S.sub.2.sup.2−, S.sub.4.sup.2−, although the polysulfides S.sub.3.sup.2−, S.sub.5.sup.2−, S.sub.6.sup.2− may also be present in the overall weight. Thus, sodium polysulfide is a compound with the overall formula of NaSnNa, while monoethanolamine polysulfide is HOCH.sub.2CH.sub.2NH.sub.3 S.sub.nNH.sub.3CH.sub.2CH.sub.2OH. Polysulfides may be obtained by methods known in the prior art in situ, for example, by fusion of elemental sulfur and alkali, or by dissolving elemental sulfur into ethanolamine while heating, or be obtained in the form of ready-made substances for sale on the market.

[0036] A change in the share of components that goes beyond the limits indicated above, leads to a degradation of the result or to unproductive consumption of reagent. An increase in the share of inorganic base salts or alkali metal nitrite above the limits indicated above results in problems with the solubility of components, and an undesired growth in solution density.

[0037] The proposed neutralizer of hydrogen sulfide and mercaptanes under normal conditions is a uniform mobile liquid whose color is light yellow to saturated yellow in color, with a density within the limits of 1.05-1.34 g/cm.sup.3, and a hydrogen indicator of pH 11.0 and greater (depending on the content of the inorganic base, alkylamine and polysulfides).

[0038] For better comprehension, the invention may be illustrated, but not exhaustively, by the following non-limiting examples of its specific implementation.

EXAMPLES

Example 1

[0039] In preparing the neutralizer, dry reagents are added to the solution sequentially after all the previous additives have dissolved. The liquid reagents are added after the dry reagents have dissolved. Mix until a uniform product is obtained. All preparation is done at room temperature.

[0040] Into a vessel equipped with a mechanical mixer, 79 g of water is added, and 14 g of sodium hydroxide is loaded into it, after dissolving, 4 g of sodium polysulfide is added, after dissolving 3 g of diethanolamine is added and mixed until a uniform product is obtained. The obtained composition A1 with a content by weight % of sodium polysulfide 4, potassium hydroxide 14, diethanolamine 5, and water—remainder, is used for neutralization of hydrogen sulfide and light mercaptanes.

[0041] Similarly, other compositions are also obtained, with weight by %: [0042] A2: sodium polysulfide—4, potassium hydroxide—14, sodium nitrate—10, diethanolamine—5, water—remainder. [0043] A3: monoethanolamine polysulfide—8, potassium hydroxide—11, sodium nitrate—10, amylamine—4, water—remainder. [0044] A4: diethanolamine polysulfide—10, sodium hydroxide—25, monoethanolamine—6, Water—remainder. [0045] P (prototype, RU 2241018): sodium hydroxide—5, monoethanolamine—6, sodium nitrite—20, water—remainder. [0046] A6: diethanolamine polysulfide—6, sodium hydroxide—14, ethylenediamine—7, water—remainder. [0047] A7: diethanolamine polysulfide—6, sodium hydroxide—14, ethylenediamine—20, water—remainder. [0048] A8: potassium polysulfide—5, sodium hydroxide—10, diethylamine—5, sodium nitrite—10, water—remainder. [0049] A9: potassium polysulfide—0.5, sodium hydroxide—10, diethylamine—5, sodium nitrite—10, water—remainder. [0050] A10: potassium polysulfide—5, sodium hydroxide—1, diethylamine—5, sodium nitrite—10, water—remainder. [0051] A11: potassium polysulfide—5, sodium hydroxide—1, diethylamine—0.5, sodium nitrite—10, water—remainder.

Examples 2-25

[0052] In the examples presented, a test of the composition for effectiveness in neutralizing hydrogen sulfide and light methyl and ethyl mercaptanes is conducted for the following raw-material products. [0053] High-sulfur-content H1 oil, containing hydrogen sulfide—86 ppm, total methyl and ethyl mercaptanes—214 ppm. [0054] High-sulfur—content H2 oil, containing hydrogen sulfide, 256 ppm, methyl and ethyl mercaptanes—not present. [0055] GC gas condensate, hydrogen sulfide content—2 ppm, total methyl and ethyl mercaptanes—1325 ppm. [0056] Benzene fraction of cracking BC (n.c.—205° C.), hydrogen sulfide content—120 ppm, total methyl and ethyl mercaptanes—457 ppm, test on copper strip as per GOST 6321-92—did not pass (class 3 A).

[0057] The test of the composition for effectiveness in neutralizing hydrogen sulfide and light methyl and ethyl mercaptanes in the raw material is conducted in an unheated reaction flask incorporating a mixer at room temperature. The calculated amounts of raw material and neutralizer are placed in the flask. The mass of the raw material and neutralizer is determined by weight. After the calculated time, the mixer is stopped and the sample is removed for analysis. The experimental results are presented in Table 3.

TABLE-US-00003 TABLE 3 Example Neutralizer, Raw material Processing time, Processing time, Test on copper Number dosage product result (ppm) result (ppm) strip 1 A1, 400 g/τ H1 2 hours, 14 hours, H2S = none. H2S = none RSH = 101 RSH = 12 2 A1, 320 g/τ H2 2 hours, 14 hours H2S = 132. H2S = none 3 A1, 2000 g/τ G 4 hours, 14 hours, H2S = none H2S = none RSH = 550 RSH = 21 4 A2, 400 g/τ H1 2 hours, 14 h   ., H2S = none H2S = none RSH = 94 RSH = 8 5 A2, 320 g/τ H2 2 hours, 14 hours, H2S = 101 H2S = none 6 A2, 2000 g/τ G 4 hours, 24 hours, H2S = none. H2S = none RSH = 376 RSH = 2 7 A3, 400 g/τ H1 2 hours, 14 h   ., H2S = 12 H2S = none RSH = 87 RSH = 21 8 A3, 320 g/τ H2 2 hours, 14 hours, H2S = 122 H2S = none. 9 A3, 2000 g/τ G 7 hours, 7 hours, H2S = none H2S = none RSH = 453 RSH = 28 10 A4, 500 g/τ H1 1 hour, 7 hours, H2S = none H2S = none RSH = 91 RSH = 2 11 P, 500 g/τ H1 1 hour, 14 hours, H2S = 56 H2S= none RSH = 181 RSH = 66 12 A5, 500 g/τ H1 1 hour, 14 hours, H2S = 44 H2S = none RSH = 114 RSH = none 13 A4, 700 g/τ BC 3 hours, 12 hours, Passed H2S = none H2S = none (Class 1A) RSH = 117 RSH = 11 14 P, 700 g/τ BC 3 hours, 12 hours, Did not pass H2S = 51 H2S = none (class 2B) RSH = 328 RSH = 125 15 A5, 700 g/τ BC 3 hours, 12 hours, Passed H2S = none H2S = none (Class 1A) RSH = 224 RSH = 16 16 A6, 700 g/τ BC 3 hours, 12 hours, Passed H2S = none H2S = none (Class 1A) RSH = 217 RSH = 23 17 A7, 700 g/τ BC 3 hours, 12 hours, Passed H2S = none H2S = none (Class 1A) RSH = 208 RSH = 21 18 A8, 2000 g/τ G 7 hours, 16 hours, H2S = none H2S = none RSH = 420 RSH = 21 19 A9, 2000 g/τ G 7 hours, 16 hours, H2S = none H2S = none RSH = 510 RSH = 112 20 A10, 2000 g/τ G 7 hours, 16 hours, H2S = 1 H2S = none RSH = 890 RSH = 670 21 A11, 2000 g/τ G 7 hours, 16 hours, H2S = 1 H2S = none RSH = 608 RSH = 420 22 A8, 290 g/τ H2 1 hour, 15 hours, H2S = 155 H2S = none 23 A9, 290 g/τ H2 1 hour, 15 hours, H2S = 196 H2S = 78 24 A8, 720 g/τ BC 3 hours, 12 hours, Passed H2S = none H2S = none (Class 1A) RSH = 110 RSH = none 25 A9, 720 g/τ BC 3 hours, 12 hours, Did not pass H2S = none H2S= (class 3A) RSH = 211 RSH = 82

[0058] The examples presented demonstrate that it is possible to purify the raw material from mercaptanes only, or separately from hydrogen sulfide, or do simultaneous removal of hydrogen sulfide and mercaptanes.

[0059] Examples 10-15 show the improvement in results of processing as compared with the prototype both of the level of reduction in mercaptanes and hydrogen sulfide, and in testing of corrosion on a copper strip.

[0060] Examples 16-17 show that the increase in alkylamine content beyond the limits indicated for this invention, does not bring about a substantial improvement in the result.

[0061] Examples 1-6 show that addition of sodium nitrite into the composition results in a reduced processing time.

[0062] Examples 18-25 show that reduction in the content of a component below the limits indicated for this invention (potassium disulfide in examples 18, 19, 22, 23, 24, sodium hydroxide in example 20, and alkylamine in example 21) results in impairment in purification and the copper strip corrosion indicator.