KR20130047739A - Use of alpha-amino ethers for the removal of hydrogen sulfide from hydrocarbons - Google Patents

Abstract

The present invention provides a method for removing hydrogen sulfide from a hydrocarbon fluid. The method involves using alpha-amino ether as the hydrogen sulfide scavenger. This allows for the introduction of oil soluble scavenger instead of water soluble scavenger.

Description

Use of alpha-amino ether to remove hydrogen sulfide from hydrocarbons {USE OF ALPHA-AMINO ETHERS FOR THE REMOVAL OF HYDROGEN SULFIDE FROM HYDROCARBONS}

Cross-reference to related application

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Statement on Federally Supported Research or Development

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The present invention generally relates to the treatment of acid gas and liquid hydrocarbons to remove or reduce the level of hydrogen sulfide in acid gases and liquid hydrocarbons. The toxicity of hydrogen sulfide in hydrocarbon fluids is well known in the industry. Significant cost and effort are spent every year in reducing its content to safe levels.

In large production plants, it is generally more economical to install a regenerative system for treating a sour gas stream. Such systems typically use compounds used in absorption towers to contact the resulting fluids and selectively absorb hydrogen sulfide and other possible toxic substances such as carbon dioxide and mercaptan. This absorbent compound is then regenerated and reused in this system. Typical hydrogen sulfide absorbing materials include alkanolamines, PEGs, hindered amines, and other species that can be recycled.

Nonregenerative scavengers for small plant hydrogen sulfide removal are generally divided into four categories: 1) aldehyde based, 2) metallic oxide based, 3) caustic based, and 4 ) Other processes. In the removal of hydrogen sulfide by non-renewable compounds, the scavenger reacts with hydrogen sulfide to form nonlethal compounds or compounds that can be removed from hydrocarbons. For example, when formaldehyde reacts with hydrogen sulfide, a compound known as formthional (eg, trithiane) is formed.

Prior art aldehyde scavengers typically include low molecular weight aldehydes and ketones and adducts thereof. Low molecular weight aldehydes may also be combined with alkyl or alkanolamines as described in US Pat. No. 4,748,011. Other aldehyde derived scavengers include reaction products of low molecular weight alkanolamines and aldehydes as described in US Pat. No. 4,978,512. PCT application WO 92/01481 describes a method for reducing sulfide in other applications using certain 3-substituted hexahydro-s-triazines. German document DE4027300 describes a regenerative solvent for removing H ₂ S and mercaptans. U. S. Patent 5,347, 004 describes the use of 1,3,5-alkoxyalkylene hexahydro triazine. PCT application WO 91 US 5232 describes a hydroxyalkyl triazine scavenger, in particular N, N ', N "-tris (2-hydroxyethyl) hexahydro-s-triazine. 5,774,024 describes combinations of alkyl triazine scavengers and quaternary ammonium salts that enhance the efficacy of alkyl-triazines.However, these prior art attempts are often water based chemicals, Significant mixing is required to effectively contact hydrocarbon fluids and remove hydrogen sulfide.

Accordingly, there is clearly a need and utility for an improved method of scavenging hydrogen sulfide from hydrocarbon fluids using a scavenger that is soluble in the hydrocarbon fluid to be treated. The techniques described in this section are not intended to be admitted that any patent, publication or other information referred to herein is a "prior art" with respect to the invention, unless otherwise specified in detail. In addition, this section should not be construed to mean that a search has been conducted or that no other relevant information as provided in 37 CFR § 1.56 (a) exists.

At least one embodiment of the invention relates to a method for removing hydrogen sulfide from a hydrocarbon fluid. The method includes contacting a fluid with a composition comprising an effective amount of hydrogen sulfide scavenger. The amount of hydrogen sulfide scavenger is sufficient to react with hydrogen sulfide to reduce the amount of hydrogen sulfide released to the vapor spcae. The reaction product of the hydrogen sulfide scavenger and hydrogen sulfide is soluble in hydrocarbon fluids. Hydrogen sulfide scavenger contains at least one alpha-amino ether.

The composition comprises

N, N'-oxybis (methylene) bis (N, N-dibutylamine),

N, N '-(methylenebis (oxy) bis (methylene)) bis (N, N-dibutylamine),

And one or more items selected from the group consisting of any combination thereof.

The sulfide scavenging formulation and the reaction product of hydrogen sulfide may not form a separate fluid layer. The method may also further comprise reacting the secondary amine with formaldehyde equivalents to form at least a portion of the scavenging formulation. The hydrocarbon fluid may be a liquid.

For the purposes of the present application, the definitions of terms are as follows:

"Alpha-amino ether" means a molecule according to the formula:

Wherein R ₁ , R ₂ , R ₃ and R ₄ are carbon containing side chains containing 1 to 20 carbon atoms and include cyclic and acyclic compounds. The cyclic compound may be aromatic or non-aromatic. Examples include, but are not limited to, methyl, ethyl, propyl, tert-butyl, cyclopentyl, cyclohexyl, morpholino, and phenyl, all of which may be the same group or one or more different groups. B is an ether group which is an oxygen atom or a group having an oxygen atom at both ends (eg, —OCH ₂ O— or —OC ₂ H ₄ O—).

“Formaldehyde equivalents” means a composition of matter, and / or formaldehyde or related molecules, such as at least one group according to the formula (CH ₂ O) _n where n is an integer of 1 or more. Means a material comprising paraformaldehyde, and / or s-trioxane.

"Hydrocarbon fluids" are kerosene, crude oil, crude oil emulsions, oilfield condensate, petroleum residua, refined fuel, distillate fuel, fuel oil, heating oil, diesel fuel, gasoline, jet fuel, bunker fuel oil, and their By liquid or gas, mainly comprising organic materials, including but not limited to any combination.

"Non-Regenerative Scavenger" means a scavenger consumed by a scavenging process.

"Regenerative Scavenger" means a scavenger that is not consumed by the scavenging process.

A "scavenger" is a substance such as, but not limited to, alpha-amino ether, useful for reducing the amount of or alleviating the effects of some other substance, such as, but not limited to, mercaptan in a fluid medium. Means.

This application, if the definitions or descriptions set forth herein do not correspond (explicitly or implicitly) to the meanings described in the sources generally used in the Dictionary or incorporated herein by reference. And the terms in the claims are specifically interpreted according to the definition or description of the present application and not according to the conventional definition, the dictionary definition or the definition included by reference. In view of the above description, in situations where the term can only be understood when the term is interpreted in a dictionary, the term is described in Kirk - Othmer. Encyclopedia of Chemical Technology , 5th Edition, (2005), (Published by Wiley, John & Sons, Inc.), these definitions will limit how terms are defined in the claims.

In at least one embodiment, the hydrogen sulfide in the hydrocarbon fluid is reduced by introducing an alpha-amino ether scavenger into the fluid.

In at least one embodiment, the alpha-amino ether is part of the scavenging formulation used in the hydrocarbon fluid. The formulation includes alpha-amino ether and may also consist of a carrier liquid. The formulation may be introduced into the hydrocarbon fluid by mechanical means, including but not limited to an infusion pump or any of the mechanisms described in US Pat. Nos. 5,744,024 and 5,840,177. In the environment of gaseous hydrocarbon fluids, the gas may proceed through an absorption tower containing a scavenging formulation.

One advantage of the use of alpha-amino ether scavenger over other scavenger is that such scavenger is soluble in hydrocarbon fluids, since the alpha-amino ether scavenger is not a water based product.

As shown in FIG. 1, in at least one embodiment, a hydrogen sulfide scavenger is produced by reacting a secondary amine with formaldehyde or other formaldehyde equivalents, such as paraformaldehyde or s-trioxane. This results in a composition of matter comprising mainly two forms of alpha-amino ethers (compounds B and C). 10% to 25% of the composition is a mono oxygen ether (Compound B) and 50% to 80% of the composition is a bis oxygen ether (Compound C) with a single carbon atom between the ether oxygens. The reaction product also contains 10 to 25% of non-ether diamines (Compound A). Compound A is an inevitable byproduct of the reaction mixture. This reaction can be carried out by reacting the reactants with a naphtha (Petroleum) Heavy Aromatic Solvent (e.g. Aromatic 150 and Solvesso (ExxonMobil)), or a naphtha light aromatic solvent (e.g. Aromatic 100 (Americhem Sales Corporation) By mixing in a solvent such as (but not limited to)).

In at least one embodiment, the ratio of amine to formaldehyde in the reaction mixture is generally in the range of 1.5: 1 to 1: 1.5 and is preferably 1.2: 1 to 1: 1.2.

In at least one embodiment, any group of the R and R 'groups corresponds to any of R ₁ , R ₂ , R ₃ and R ₄ described in the definition of “alpha-amino ether”.

In at least one embodiment, when R is n-butyl and R 'is H,

Compound A is N, N, N ', N'-tetrabutylmethanediamine,

Compound B is N, N'-oxybis (methylene) bis (N, N-dibutylene),

Compound C is N, N '-(methylenebis (oxy) bis (methylene)) bis (N, N'-dibutylamine).

At least some contemplated scavenging compositions include (Compounds A, B, and C), (A and B), (A and C), (B and C), (C alone), and (B alone) Contains formulations.

Example

The foregoing may be more readily understood with reference to the following examples, which are described for purposes of illustration and are not intended to limit the scope of the invention.

Samples of hydrocarbon fluids were tested to determine the efficacy of the scavenger. Table 1 compares the compositions of the invention in naphtha at 22 ° C. Table 2 compares kerosene at 22 ° C. and Table 3 compares three slurry oils (eg, carbon black oil, decant oil, and refined slurry oil produced at a refinery). will be. These samples contained varying levels of hydrogen sulfide and were similarly treated with or without varying doses of alpha-amino ether scavenger and recorded the amount of reduced H ₂ S in each sample.

Table 1: Naphtha, 22 ° C

Table 2: Kerosene, 22 ° C

Table 3: Slurry Oil 97 ° C

The amount of H ₂ S present in the vapor space was determined by measuring the vapor space hydrogen sulfide level according to ASTM D5705-03. The test procedure was modified by running at a temperature other than 60 ° C. The 1-gallon sample was divided into several 500 milliliter samples for testing. After pre-administration of Compound A to Compound C in the treated container, the fluid to be tested was poured into the container.

In each example, the dose ratio is the number used to determine the throughput (ppm) for the sample. For Table 1, the untreated sample showed 800 ppm vapor space hydrogen sulfide measurements. A dose ratio of 0.2 indicates that the sample was treated with 160 ppm of additive. A dose ratio of 0.3 indicates that it has been treated with an additive of 240 ppm.

These data indicate that the presence of alpha-amino ether scavenger reduced H ₂ S in hydrocarbon fluids in a relatively short time and continued to decrease H ₂ S when the sample was exposed to alpha-amino ether for a longer time before testing. Prove that.

Although the invention may be embodied in many different forms, particularly preferred embodiments of the invention are shown in the drawings and described in detail herein. The subject matter of the present invention is illustrative of the principles of the invention and is not intended to limit the invention to the specific embodiments illustrated. All patents, patent applications, scientific papers, and any other references mentioned herein are incorporated by reference in their entirety. In addition, the present invention includes any possible combination of some or all of the various embodiments described herein and incorporated herein.

The foregoing is illustrative and not exhaustive. This description will suggest many variations and alternatives to those skilled in the art. All such alternatives and modifications are intended to be included within the scope of the claims, where the term "comprising" means "including, but not limited to". Those skilled in the art can also recognize other equivalents to the specific embodiments described herein, which equivalents are intended to be encompassed by the claims.

All ranges and parameters described herein are understood to include any and all subranges included in such ranges and parameters, and all numbers between such endpoints. For example, the stated range of "1 to 10" will be considered to include any and all subranges between the minimum value of 1 and the maximum value of 10, including the boundary value, i.e. all subranges are 1 or Starts with a minimum of more (e.g., 1 to 6.1), ends with a maximum of 10 or less (e.g., 2.3 to 9.4, 3 to 8, 4 to 7), and finally each number 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 are included within this range.

This describes the description of the preferred and alternative embodiments of the invention. Those skilled in the art can recognize other equivalents to the specific embodiments described herein, and such equivalents are intended to be included in the claims appended hereto.

Claims (4)

A method of reducing the amount of hydrogen sulfide in a hydrocarbon fluid by contacting a hydrocarbon fluid with a composition comprising an effective amount of hydrogen sulfide scavenger, wherein the amount of hydrogen sulfide scavenger is sufficient to react with hydrogen sulfide to reduce hydrogen sulfide in the vapor phase. Wherein the reaction product of the hydrogen sulfide scavenger and hydrogen sulfide is soluble in the hydrocarbon fluid and the hydrogen sulfide scavenger reduces the amount of hydrogen sulfide in the hydrocarbon fluid containing at least one alpha-amino ether. The composition of claim 1 wherein the composition is
N, N'-oxybis (methylene) bis (N, N-dibutylamine),
N, N '-(methylenebis (oxy) bis (methylene)) bis (N, N-dibutylamine), and
A method comprising one item selected from the group consisting of any combination thereof which may include N, N, N'N'-tetrabutylmethanediamine. The method of claim 1, wherein the reaction product of a sulfide scavenging formulation and hydrogen sulfide does not form a separate fluid layer. The method of claim 1, further comprising reacting the secondary amine with formaldehyde equivalents to form some or all of the scavenging formulation.

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