JP2013532735A - Improved method for removing hydrogen sulfide - Google Patents

Abstract

The present invention provides a method for removing hydrogen sulfide from a hydrocarbon fluid. The method includes using nitrogen oxide molecules to facilitate sulfide scavengers such as alkyl-triazines. Nitrogen oxides effectively accelerate the scavenger activity. This makes it possible to avoid the introduction of halides into the hydrocarbon stream.

Description

  The present invention relates to an improved method for removing hydrogen sulfide.

(Cross-reference of related applications)
None.
(Description of research and development funded by the federal government)
Not applicable.

  The present invention generally relates to the treatment of acid gases and liquid hydrocarbons to remove or reduce the level of hydrogen sulfide therein. The toxicity of hydrogen sulfide in hydrocarbon streams is known in the industry, and significant costs and efforts are expended every year to reduce its content to a safe level.

  In large manufacturing facilities, it is generally more economical to install a regeneration system for treating acid gas streams. These systems typically employ compounds used in absorption towers to contact the produced fluid and selectively absorb hydrogen sulfide and possibly other toxic materials such as carbon dioxide and mercaptans. . The absorbing compound is then regenerated and reused in the system. Typical hydrogen sulfide absorbing materials include alkanolamines, PEGs, hindered amines, and other species that can be regenerated.

  Non-regenerative scavengers for small factory hydrogen sulfide removal fall into four general categories: 1) aldehyde systems, 2) metal oxide systems, 3) corrosive systems, and 4) other processes. Is done. In removing hydrogen sulfide with non-regenerative compounds, the scavenger reacts with hydrogen sulfide to form a non-toxic compound or compound, which can be removed from the hydrocarbon. For example, when formaldehyde reacts with hydrogen sulfide, a chemical compound known as formthional (eg, trithiane) is formed.

Prior art aldehyde scavengers typically include low molecular weight aldehydes, as well as ketones and adducts thereof. Low molecular weight aldehydes may also be combined with alkyl or alkanolamines as disclosed in US Pat. No. 4,748,011. Other aldehyde-derived scavengers include low molecular weight alkanolamines and aldehyde reaction products, as disclosed in US Pat. No. 4,978,512. PCT application WO 92/01481 discloses a method for reducing sulfides in sewage gas using certain tri-substituted-hexahydro-s-triazines. German reference DE 4027300 discloses a regenerating solvent for removing H ₂ S and mercaptans. US Pat. No. 5,347,004 discloses the use of 1,3,5-alkoxyalkylene hexahydrotriazine. PCT application WO91US5232 discloses hydroxyalkyltriazine scavengers, specifically N, N ′, N ″ -tris (2-hydroxyethyl) hexahydro-s-triazine. US Pat. No. 5,774,024 discloses a combination of an alkyl triazine scavenger and a quaternary ammonium salt, where the quaternary ammonium salt enhances the effectiveness of the alkyl-triazine.

US Pat. No. 4,748,011 US Pat. No. 4,978,512 International Publication No. 92/01481 Pamphlet German Patent Application No. 4027300 US Pat. No. 5,347,004 US Pat. No. 5,774,024

  Thus, there is a clear need and utility for an improved method of scavenging hydrogen sulfide from hydrocarbon fluids. The technology described in this section is "prior art" with respect to the present invention, unless specifically indicated as such, any patents, publications, or other information referred to herein. I do not intend to approve that. In addition, this section should not be construed to mean that research is being conducted or that there is no other relevant information as defined in 37 CFR §1.56 (a).

  At least one embodiment of the present invention is directed to a method for removing hydrogen sulfide from a hydrocarbon fluid. The method includes contacting the fluid with an effective amount of a sulfide scavenger formulated with a nitrogen oxide promoter. The amount of nitrogen oxide promoter is sufficient to accelerate the scavenger scavenging action as compared to the scavenger scavenging action in the absence of the nitrogen oxide promoter.

  For purposes of this application, these terms are defined as follows:

“Alkyl-triazine” has the formula:

Wherein R ₁ , R ₂ , R ₃ are alkyl groups such as methyl, ethyl, propyl, isopropyl, t-butyl, or substituted alkyl groups such as CH ₂ CH ₂ OH R ₁ , R ₂ , R ₃ can all be the same group or one or more different groups. Alkyl-triazines include, but are not limited to, the triazines disclosed in US Pat. No. 5,744,024.

  “Hydrocarbon fluids” are primarily organic, including but not limited to kerosene, crude oil, distillate fuel, fuel oil, kerosene, diesel fuel, gasoline, jet fuel, bunker fuel oil, and any combination thereof. Means liquid or gas containing material.

“Methyltriazine” means an alkyl-triazine in which R ₁ , R ₂ , and R ₃ are all methyl groups.

Nitrogen oxide "has the formula:

Wherein R ₁ , R ₂ , and R ₃ are any alkyl groups containing 1 to 30 carbon atoms and include cyclic compounds.

  “Non-regenerative scavenger” means a scavenger consumed by the scavenging process.

  “Regenerative scavenger” means a scavenger that is not consumed by the scavenging process.

  “Accelerator” means a composition that does not scavenge itself, but significantly increases the effectiveness of the scavenger when combined with a known scavenger.

  “Salt” means a compound comprising an anion and a cation that is normally ionized in solution.

  “Sweeper” means a composition such as, but not limited to, an alkyltriazine that is useful in reducing the amount of any other composition such as, but not limited to, hydrogen sulfide in a fluid medium.

  The above definitions, or explanations elsewhere in this application, may have commonly used meanings, meanings in the dictionary, or meanings given in references incorporated by reference to this application (explicit or In the case of conflict with (implicit), the terms of this application, and particularly the claims, should be interpreted according to the definitions or explanations in this application rather than following the general definitions, dictionary definitions, or definitions incorporated by reference. It is understood. Based on the above, if a term can only be understood if it is interpreted by a dictionary, the term is Kirk-Othmer Encyclopedia of Chemical Technology, 5th Edition (2005) (Published by Wiley & John, Jon , Inc.), this definition shall govern how the term is to be defined in the claims.

  In at least one embodiment, the amount of hydrogen sulfide in the hydrocarbon fluid is reduced by the introduction of an alkyl-triazine scavenger with a nitrogen oxide promoter. Accelerators increase the effectiveness of alkyl-triazine scavengers. Nitrogen oxide is a single component and is superior to prior art quaternary ammonium salt promoters because it does not contain halides such as chlorides.

  The effectiveness of nitrogen oxides as a promoter is unexpected because it is a single neutral compound. In at least one embodiment, the accelerator is 1-25% of the scavenger / accelerator-containing composition.

  In at least one embodiment, at least a portion of the triazine is synthesized according to the process described in US Pat. No. 5,744,024.

  In at least one embodiment, the nitrogen oxides are mixed with a solution of alkyl triazine, the solvent can be water, and the solution with nitrogen oxides is introduced into the hydrocarbon fluid. In at least one embodiment, the nitrogen oxide introduction is concurrent with the alkyl-triazine introduction. The properties of nitrogen oxide promoters are such that they are extremely effective in several different hydrocarbon fluids.

  One advantage of using a nitrogen oxide promoter with a scavenger over prior art scavengers is that the nitrogen oxide promoter is not a salt (it is not a combination of anions and cations), and therefore The lack of halide, especially the lack of chloride.

  In at least one embodiment, the scavenging formulation is used in a hydrocarbon stream. The formulation includes a solvent, an alkyl-triazine, and a nitrogen oxide. The solvent is selected from the list consisting of water, alcohols, aromatic solvents, alkyl-triazines, solvents that solvate nitrogen oxides with each other, and any combination thereof. The formulation is introduced into the hydrocarbon stream by infusion pump or mechanical means including, but not limited to, any mechanism disclosed in US Pat. Nos. 5,744,024 and 5,840,177. can do. In the context of a gaseous hydrocarbon fluid, the gas may pass through an absorption tower containing the scavenging formulation.

  In at least one embodiment, the hydrocarbon fluid is in a liquid state. In at least one embodiment, the hydrocarbon fluid is in a gaseous state.

  The foregoing can be better understood by reference to the following examples, which are presented for purposes of illustration and are not intended to limit the scope of the invention.

A sample of the acidic hydrocarbon stream (fuel oil) was tested to determine the efficiency of the triazine formulated with the accelerator relative to the triazine formulated without the accelerator. Samples were relatively treated with various doses of methyltriazine scavenger, methyltriazine scavenger with accelerator, and the amount of residual H ₂ S for the various samples was recorded. Table 1 compares compositions of the present invention at different concentrations, Table 2 compares accelerated scavengers to unaccelerated scavengers, and Table 3 shows accelerators over time. Compare methyltriazines with and without.

  Vapor space hydrogen sulfide levels were measured according to the procedure described by ASTM D5705-03. The test procedure was modified with respect to Tables 2 and 3 by performing the test in kerosene at room temperature which was about 22 ° C. instead of 60 ° C.

This data demonstrates that the presence of nitrogen oxides allows methyl triazine scavengers to be faster and reduce the level of H ₂ S than methyl triazines without accelerators.

  While the invention may be embodied in many different forms, specific preferred embodiments of the invention are illustrated in the drawings and are described in detail herein. This disclosure is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated. All patents, patent applications, scientific papers, and any other referenced material mentioned herein are incorporated by reference in their entirety. Furthermore, the present invention encompasses any possible combination of some or all of the various embodiments described herein and incorporated herein.

  The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many modifications and alternatives to one of ordinary skill in this art. All these alternatives and modifications are intended to be included within the scope of the claims, and the term “comprising” includes, but is not limited to, including, but not limited to. "Means. Those skilled in the art will recognize other equivalents to the specific embodiments described herein, which are also intended to be encompassed by the claims.

  All ranges and parameters disclosed herein are understood to include any and all sub-ranges contained therein, as well as any number between endpoints. For example, a stated range of “1 to 10” is any and all subranges between (and including) a minimum value of 1 and a maximum value of 10, ie, a minimum value of 1 or more ( For example, from all sub-ranges, starting with 1 to 6.1) and ending with a maximum value of 10 or less (eg 2.3 to 9.4, 3 to 8, 4 to 7) Should be considered to include each number of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 contained within.

  This concludes the description of the preferred and alternative embodiments of the present invention. Those skilled in the art will recognize other equivalents to the specific embodiments described herein, which equivalents are intended to be encompassed by the claims appended hereto.

Claims (4)

  A method of reducing the amount of hydrogen sulfide in a hydrocarbon fluid comprising contacting the fluid with an effective amount of the composition, the composition comprising a sulfide scavenger, a nitrogen oxide promoter, And the amount of the nitrogen oxide promoter is used to accelerate the scavenging action of the scavenger as compared to the scavenging action of the scavenger in the absence of the nitrogen oxide accelerator. Enough, way.   The method of claim 1, wherein the scavenger is an alkyl-triazine.   The method of claim 1, wherein the hydrocarbon fluid is a liquid.   The method of claim 1, wherein no halide is added to the hydrocarbon fluid.