Use of triazine-containing silica nanoparticles for H2S capture

Abstract

H from Stream 2 1. A method for removing S, comprising adding a silica nanoparticle composition, and optionally a triazine, wherein the stream is an oil stream, a gas stream, a CO 2 point source purification streams, and geothermal energy system streams.

Description

[Technical Field]

[0001] The present invention relates to the field of chemicals used to remove hydrogen sulfide (H2S) from oil streams, gas streams, CO2 point source cleanup and geothermal energy systems. [Background technology]

[0002] Hydrogen sulfide is present in natural gas from many gas fields and may also be present in oil and gas streams, CO2 point source cleanup, and geothermal energy systems.

[0003] It is a highly undesirable component because it is toxic, corrosive and has a very unpleasant odor, so several methods have been developed for its removal.

[0004] One such method involves injecting an aqueous solution of 1,3,5-tris(2-hydroxyethyl)hexahydro-s-triazine into a gas stream. Because triazine is a liquid scavenger, this process is economical for up to approximately 50 kg of HS per day, removing HS to about 5 ppm in streams containing relatively low concentrations of HS. However, because the products and details of the reaction are unknown, optimal conditions for HS removal cannot always be applied. See "Hydroxylysis of 1,3,5-Tris(2-hydroxyethyl)hexahydro-s-triazine and Its Reaction with HS," Ind. Eng. Chem. Res. 2001, 40, 6051-6054, page 6051. https: / / www.corrosionpedia.com / definition / 1645 / hydrogen-sulfide-scavenger-hs-scavenger

[0005] Hydrogen sulfide (H2S) scavengers are specialized chemical or fuel additives widely used in hydrocarbon and chemical processing facilities. These specialized chemicals selectively react with and remove H2S, helping to meet product and process specifications. Products treated for H2S include crude oil, fuels, and other refined petroleum products in storage tanks, tanker ships, rail cars, and pipelines.

[0006] Hydrogen sulfide can damage piping by reacting directly with steel to form iron sulfide corrosion films or by increasing the acidity of the liquid / gas mixture within the pipe. H2S can be oxidized to elemental sulfur when dissolved in water, which can also produce iron sulfide corrosion films when in direct contact with metal surfaces. Therefore, it is essential to remove H2S from crude oil as quickly and efficiently as possible. Triazines, the most commonly used liquid H2S scavengers, have a heterocyclic structure similar to cyclohexane, but with three carbon atoms replaced by nitrogen atoms. The oilfield term triazine differs from the IUPAC common name triazinane.

[0007] There are three variations of triazines based on the substitution position of the nitrogen atom: 1,2,3-triazine, 1,2,4-triazine, and 1,3,5-triazine (also known as s-triazine).

[0008] Further variations, including substitution of hydrogen atoms with other functional groups, are used in various industries. This substitution occurs at any number of "R" positions: 1, 2, 3, 4, 5, or 6. Different substitutions result in different reactivities with HS, changes in the solubility of the triazine, and changes in the solubility of the reaction products ("R" groups). Thus, triazines can be "tuned" to better suit applications or disposal considerations.

[0009] direct injection In direct injection applications, triazine is sprayed directly into a gas or mixed fluid stream, typically using an atomizing quill. The removal rate depends on the dissolution of H2S into the triazine solution, not the reaction rate. As a result, gas flow rate, contact time, and mist size and distribution contribute to the final scavenger performance. This method excels at removing H2S when there is good annular mist flow and sufficient time for reaction. Most suppliers recommend a minimum contact time of 15-20 seconds with the product for best results. While typical efficiencies are lower due to H2S dissolution in the product, removal efficiencies of approximately 40% can reasonably be expected. Careful consideration of injection location and product selection is required for direct injection to be effective.

[0010] In a contact tower, the feed gas is bubbled through a column packed with triazine. As the gas bubbles through the liquid, it dissolves in the triazine and the H2S is removed. The limiting factors in this application are the surface area of ​​the bubbles, the concentration of the solution, and the bubble transit time (contact time). Finer bubbles improve the reaction rate but can cause unwanted foaming. This application is not suitable for high gas flow rates. The H2S removal efficiency of contact towers is much higher, up to 80%. As a result, much less chemical is used, resulting in significant reductions in operating expenses ("OPEX"). However, contact towers and chemical storage require significant space and weight, making them less practical for offshore applications.

[0011] The reaction of one mole of triazine with two moles of H2S results in the formation of a dithiazine as the major by-product. An intermediate product is formed but is rarely observed. The R group released during the two-step reaction varies depending on the source and can be tailored for solubility. Continuing the reaction can result in the formation of an insoluble trithiane product.

[0012] The reacted triazine by-products are readily biodegradable and relatively non-toxic. Excess unreacted triazine is highly aquatic toxic and tends to form carbonate scale with produced water or seawater. This can lead to emulsion stabilization and an increase in the overboard oil-in-water (OIW) content.

[0013] Unreacted triazines are also problematic for refineries because they can affect the desalting process and cause accelerated corrosion in crude distillation units. They can also cause foaming in glycol and amine units and discoloration of glycol units. An unpleasant odor has also been reported from excessive use of triazine, although some suppliers offer low-odor versions. While triazine itself is relatively safe to handle, it can cause chemical burns on contact.

[0014] Triazines and derivatives are used successfully by many operators and facilities worldwide. They are also used in a variety of other applications where control of low levels of H2S is essential, including scale remediation and reservoir stimulation. In the United States, they are commonly used in sour shale gas production.

[0015] Triazines and derivatives are primarily used to remove low levels of H2S (<100 pounds per million standard cubic feet, or "ppmv / mmscf"). Their application using contact columns can increase the efficiency of H2S removal (up to twofold), but H2S levels above 200 ppmv / mmscf require the use of amine-based sweetening units. Triazines are also preferred in situations where the acid gas stream contains high levels of CO2 in addition to H2S. Triazines react preferentially with H2S, and the reaction is not inhibited by CO2, avoiding unnecessary chemical consumption. They are also preferred when concentrated sour waste gas streams cannot be contained or disposed of.

[0016] US2018 / 291284A1, "Microparticles For Capturing Mercaptans," published on October 11, 2018, is assigned to Ecolab. This now-abandoned patent application describes and claims sequestering and antifouling nanoparticle compositions useful in applications related to crude oil and natural gas production, transportation, storage, and separation, and oral hygiene. Also disclosed are methods for making the nanoparticle compositions as sequestering and antifouling agents, particularly in applications related to crude oil and natural gas production, transportation, storage, and separation, and oral hygiene.

[0017] Faeze Tari et. al., "Modified and Systematic Synthesis of Zinc Oxide-Silica Composite Nanoparticles with Optimum Surface Area as a Proper H2S Sorbent," Canadian Journal of Chemical Engineering, vol. 95, No. 4, 1 April 2017, pages 737-743, describes a study conducted to synthesize high-surface-area zinc oxide / silica composite nanoparticles via a facile and systematic process. Regarding the importance of surface area in the application of such nanoparticles, the variation of this factor was studied by varying reaction parameters including zinc acetate solution concentration, pH, and calcination temperature via response surface methodology combined with central composite design (RSM-CCD). The optimal surface area (337 m) was determined. 2 g -1 ) and non-optimal surface area (95 m 2 g -1 Comparison of two 0.1 g / g (10 wt%) ZnO / silica samples with ZnO / silica showed that the nanoparticles prepared under optimal conditions with an average diameter of about 18 nm exhibited an H2S adsorption capacity of about 13 mg per gram of adsorbent.

[0018] US5980845, "Regeneration of Hydrogen Sulfide Scavengers," issued on November 9, 1999. This issued US patent describes and claims sulfide scavenger solutions and processes that have high sulfide scavenging capacity, reduce or eliminate solids formation, and avoid the use of chemicals that present environmental concerns. The invention utilizes a dialdehyde, preferably ethanedial, to react with amines, amine carbonates, or other derivatives of amines that are liberated when certain scavenger solutions react with hydrogen sulfide and sulfides such as mercaptans. The scavenger solutions found to liberate amines are those formed by the reaction between the amine and the aldehyde.

[0019] US2013 / 004393, "Synergistic Method for Enhanced H2S / Mercaptan Scavenging," issued on October 11, 2016, as U.S. Patent No. 9,463,989 B2. This patent describes and claims that the use of a dialdehyde (e.g., glyoxal) and a nitrogen-containing scavenger (e.g., triazine) separately injected into a medium containing hydrogen sulfide (H2S) and / or mercaptans to capture H2S and / or mercaptans therefrom results in synergistically better reaction rates and overall capture efficiency, i.e., capacity, compared to the use of the same total amount of dialdehyde and nitrogen-containing scavenger but either the dialdehyde or the nitrogen-containing scavenger alone. The medium can include an aqueous phase, a gas phase, a hydrocarbon phase, and a mixture of a gas phase and / or a hydrocarbon phase with an aqueous phase.

[0020] US2009 / 065445A1, "Aromatic Imine Compounds for Use as Sulfide Scavengers," issued on July 26, 2011, as U.S. Patent No. 7,985,881 B2. This patent describes and claims compositions and methods related to aromatic imine compounds, and methods of their use. The compounds are formed from aromatic aldehydes and amino or amino derivatives. The compounds and their derivatives are useful, for example, as hydrogen sulfide and mercaptan scavengers for use in both water and petroleum products.

[0021] US2018 / 345212, "Architectured Materials as Additives to Reduce or Inhibit Solid Formation and Scale Deposition and Improve Hydrogen Sulfide Scavenging," was published on December 6, 2018. This patent application describes and claims a method for capturing hydrogen sulfide from a hydrocarbon or water stream and / or reducing or inhibiting solid or scale formation, comprising introducing into the water or hydrocarbon stream an additive composed of structured materials such as star polymers, hyperbranched polymers, and dendrimers, which may be used alone or in conjunction with aldehyde-, triazine-, and / or metal-based hydrogen sulfide scavengers. A treated fluid comprising a hydrogen sulfide-containing fluid and an additive for capturing hydrogen sulfide or reducing or inhibiting solid and scale formation, composed of structured materials such as star polymers, hyperbranched polymers, and dendrimers. The fluid may further contain an aldehyde-, triazine-, and / or metal-based hydrogen sulfide scavengers.

[0022] L. Chu et al., "Glycidoxypropyltrimethoxysilane Modified Colloidal Silica Coatings," published in Mat. Res. Soc. Symp. Proc. Vol. 435, © Materials Research Society, describes the preparation of coatings from suspensions of colloidal silica particles containing glycidoxypropyltrimethoxysilane (GPS) and a polyamine curing agent. GPS was first added to an aqueous silica suspension containing ethanol (30 wt%) to enhance mixing. The addition of GPS to the basic silica suspension favored condensation between silane monomers and oligomers, resulting in precipitation. In contrast, acidic conditions slowed the condensation reaction, which led to silane adsorption onto silica, as tracked by ATR-FTIR. After GPS addition and aging, the pH of the suspension was increased, a polyamine was added, and coatings were prepared on polyester webs. The GPS-modified coatings were denser, adhered better to polymer substrates, and could be made thicker than unmodified silica coatings.

[0023] In "Surface Chemical and Hermodynamic Properties of γ-glycidoxypropyltrimethoxysilane-Treated Alumina: An XPS and IGC Study," Chehimi et al., J. Mat. Chem., 2001, 11, 533-543, © The Royal Society of Chemistry 200, alumina and hydrated alumina were treated with hydrolyzed γ-glycidoxypropyltrimethoxysilane (GPS) in aqueous solution. The powders were then dried at various temperatures ranging from room temperature to 120°C. The hydration treatment used to create hydroxyl sites was found to be efficient with respect to GPS adsorption. GPS uptake was determined by quantitative XPS analysis, and the hydrated powders exhibited the highest uptake at all drying temperatures except room temperature. Summary of the Invention

[0024] A first aspect of the claimed invention is a method for removing H2S from a stream, comprising: a) one or more hydrous acidic silica nanoparticle compositions, and b) one or more triazine compounds adding The method wherein the stream is selected from the group consisting of an oil stream, a gas stream, a CO2 point source cleanup stream, and a geothermal energy system stream.

[0025] A second aspect of the invention as claimed is the process of the first aspect of the invention, wherein one of the triazines present is hexahydro-1,3,5-tris(hydroxyethyl)-s-triazine. DETAILED DESCRIPTION OF THE INVENTION

[0026] For the purposes of this patent application, silica nanoparticles include silica nanoparticles ,and and silica-alumina nanoparticles.

[0027] Silica nanoparticles can be sourced from any form of precipitated SiO2, such as: a) dry silica, b) fumed silica, c) colloidal silica, d) surface-treated silica, including silica reacted with an organosilane; e) combinations of metals or metal oxides with silica, and f) Precipitated silica.

[0028] Known methods for modifying the surface of colloidal silica include the following. 1. Covalent bonding of inorganic oxides other than silica. 2. Non-covalent attachment of small molecule, oligomeric, or polymeric organic materials (PEGylated, amine or polyamine, sulfides, etc.). 3. Covalent bonding of organic molecules, including oligomeric and polymeric species: a. Reaction with organosilanes / titanates / zirconates / germinates. b. Formation of organosilane / titanate / zirconate / germate oligomers followed by their reaction with the colloidal silica surface. c. Post-reaction formation of oligomeric / dendritic / hyperbranched / polymeric species after silane treatment, initiated from the colloidal silica surface. d. Formation of oligomeric / dendritic / hyperbranched / polymeric silanes / zirconates / titanates and their subsequent reaction on the SiO2 surface.

[0029] The silica particles contained in the colloidal silica may have any suitable average diameter. As used herein, the average diameter of the silica particles refers to the average maximum cross-sectional dimension of the silica particles. In certain embodiments, the silica particles may have an average diameter of about 0.1 nm to about 100 nm. In certain embodiments, the silica particles may have an average diameter of about 1 nm to about 100 nm. In certain embodiments, the silica particles may have an average diameter of about 5 nm to about 100 nm. In certain embodiments, the silica particles may have an average diameter of about 1 nm to about 50 nm. In certain embodiments, the silica particles may have an average diameter of about 5 nm to about 50 nm. In certain embodiments, the silica particles may have an average diameter of about 1 nm to about 40 nm. In certain embodiments, the silica particles may have an average diameter of about 5 nm to about 40 nm. In certain embodiments, the silica particles may have an average diameter of about 1 nm to about 30 nm. In certain embodiments, the silica particles may have an average diameter of about 5 nm to about 30 nm. In certain embodiments, the silica particles may have an average diameter of about 7 nm to about 20 nm.

[0030] In certain embodiments, the silica particles have an average diameter of about 30 nm or less. In another embodiment, the silica particles may have an average diameter of about 25 nm or less. In another embodiment, the silica particles may have an average diameter of about 20 nm or less. In another embodiment, the silica particles may have an average diameter of about 15 nm or less. In another embodiment, the silica particles may have an average diameter of about 10 nm or less. In another embodiment, the silica particles may have an average diameter of about 7 nm or less. In another embodiment, the silica particles may have an average diameter of at least about 5 nm. In another embodiment, the silica particles may have an average diameter of at least about 7 nm. In another embodiment, the silica particles may have an average diameter of at least about 10 nm. In another embodiment, the silica particles may have an average diameter of at least about 15 nm. In another embodiment, the silica particles may have an average diameter of at least about 20 nm. In another embodiment, the silica particles may have an average diameter of at least about 25 nm. Combinations of the above-referenced ranges are possible.

[0031] Colloidal silica is a flexible technology medium, allowing for customized surface treatment based on the application. In one embodiment, the silica is glycidoxypropyltrimethoxysilane-functionalized silica. GPTMS-functionalized silica includes alkaline sol silica available from Nissan Chemical America as ST-V3. Another GPTMS-functionalized silica is an acidic silica sol available from Nissan Chemical America as ST-OV3.

[0032] The amount of silica nanoparticles used per unit of H2S is as follows: in one embodiment, 1 unit of silica nanoparticles per 3 units of H2S, in another embodiment, 1 unit of silica nanoparticles per 5 units of H2S, and in another embodiment, 1 unit of silica nanoparticles per 10 units of H2S.

[0033] Alumina nanoparticles can be sourced from any form of precipitated Al2O3, such as: a) dry alumina; b) fumed alumina; c) colloidal alumina, d) surface-treated alumina, including alumina reacted with organosilanes; e) a combination of a metal or metal oxide with alumina, and f) Precipitated alumina.

[0034] Known methods for modifying the surface of colloidal alumina include the following. 1. Covalent bonding of inorganic oxides other than alumina. 2. Non-covalent attachment of small molecule, oligomeric, or polymeric organic materials (PEGylated, amine or polyamine, sulfides, etc.). 3. Covalent bonding of organic molecules, including oligomeric and polymeric species: a. Reaction with organosilanes / titanates / zirconates / germates. b. Formation of organosilane / titanate / zirconate / germate oligomers followed by their reaction with the colloidal alumina surface. c. Post-reaction formation of oligomeric / dendritic / hyperbranched / polymeric species after silane treatment initiated from the colloidal alumina surface. d. Formation of oligomeric / dendritic / hyperbranched / polymeric silanes / zirconates / titanates and their subsequent reaction on the Al2O3 surface.

[0035] The alumina particles contained in colloidal alumina may have any suitable average diameter. As used herein, the average diameter of the alumina particles refers to the average maximum cross-sectional dimension of the alumina particles. In certain embodiments, the alumina particles may have an average diameter of about 0.1 nm to about 100 nm. In other embodiments, the alumina particles may have an average diameter of about 1 nm to about 100 nm. In other embodiments, the alumina particles may have an average diameter of about 5 nm to about 100 nm. In other embodiments, the alumina particles may have an average diameter of about 1 nm to about 50 nm. In other embodiments, the alumina particles may have an average diameter of about 5 nm to about 50 nm. In other embodiments, the alumina particles may have an average diameter of about 1 nm to about 40 nm. In other embodiments, the alumina particles may have an average diameter of about 5 nm to about 40 nm. In other embodiments, the alumina particles may have an average diameter of about 1 nm to about 30 nm. In other embodiments, the alumina particles may have an average diameter of about 5 nm to about 30 nm. In another embodiment, the alumina particles may have an average diameter of from about 7 nm to about 20 nm.

[0036] In some embodiments, the alumina particles have an average diameter of about 30 nm or less. In some embodiments, the alumina particles have an average diameter of about 25 nm or less. In some embodiments, the alumina particles have an average diameter of about 20 nm or less. In some embodiments, the alumina particles have an average diameter of about 15 nm or less. In some embodiments, the alumina particles have an average diameter of about 10 nm or less. In some embodiments, the alumina particles have an average diameter of about 7 nm or less. In some embodiments, the alumina particles have an average diameter of at least about 5 nm. In some embodiments, the alumina particles have an average diameter of at least about 7 nm. In some embodiments, the alumina particles have an average diameter of at least about 10 nm. In some embodiments, the alumina particles have an average diameter of at least about 15 nm. In some embodiments, the alumina particles have an average diameter of at least about 20 nm. In some embodiments, the alumina particles have an average diameter of at least about 25 nm. Combinations of the above-referenced ranges are possible.

[0037] Colloidal alumina is a flexible technology medium, allowing for customized surface treatments based on the application. In one embodiment, the alumina is GPTMS-functionalized alumina. Glycidoxypropyltrimethoxysilane-functionalized alumina includes alkaline sol silica available from Nissan Chemical America as AT-V6. Another GPTMS-functionalized alumina is an acidic silica sol available from Nissan Chemical America as AT-OV6.

[0038] The amount of alumina nanoparticles used per unit of H2S is as follows: 1 unit of alumina nanoparticles per 3 units of H2S, in another embodiment 1 unit of alumina nanoparticles per 5 units of H2S, and in another embodiment 1 unit of alumina nanoparticles per 10 units of H2S.

[0039] Some examples of nanoparticles may include spherical particles, fused particles such as fused silica or fused alumina, particles grown in an autoclave to form raspberry morphologies, or elongated silica particles. These particles may be bare or surface-treated. If surface-treated, they may be polar or non-polar.

[0040] The surface treatment is sufficient to make the nanoparticles stable during transport and for delivery to areas where H2S adsorbents are needed. Stability is achieved through covalent, charge-charge, dipole-charge, or charge-dipole-charge interactions.

[0041] Triazines useful in the claimed invention include, but are not limited to, 1,2,3-triazine, 1,2,4-triazine, and 1,3,5-triazine (also known as s-triazine). Triazines useful in the claimed invention include hexahydro-1,3,5-tris(hydroxyethyl)-s-triazine.

[0042] Triazines are alkaline and can cause carbonate scaling. Triazines are commercially available.

[0043] Triazine may be present in the process at levels of about 0.1 units to about 1 unit per 3 units of H2S. Units may refer to any quantitative measure, such as grams, pounds, moles, etc.

[0044] CO2 point source purification is described in "Evaluation of CO2 Purification Requirements and the Selection of Processes for Impurities Deep Removal from the CO2 Product Stream", Zeina Abbas et al, Energy Procedia, Volume 37, 2013, Pages 2389-2396. Depending on the reference power plant, fuel type, and capture method used, the CO2 product stream will contain several impurities that can have adverse effects on pipeline transportation, geological storage, and / or enhanced oil recovery (EOR) applications. For all adverse effects, strict quality standards must be set for each application, and the CO2 stream must be purified before it can be used for any of these applications.

[0045] Abbas's paper evaluates CO2 stream specifications and impurities from conventional post-combustion capture technologies. Furthermore, it evaluates CO2-limited cleanup requirements for pipeline transportation, enhanced energy recovery, and geological storage. Comparing the impurity levels present in the CO2 stream with their limit targets, it finds that the two major impurities requiring thorough removal due to operational concerns are oxygen and water, at 300 ppmv to 10 ppmv and 7.3% to 50 ppmv, respectively. Furthermore, a list of plausible technologies for oxygen and water removal is reviewed, followed by selection of the most promising. Catalytic oxidation of hydrogen and cooling and condensation are found to be the most promising technologies for oxygen and water removal, respectively.

[0046] The "geothermal energy system stream" is described as follows: · Hot water is pumped under high pressure from deep underground through wells. · When the water reaches the surface, the pressure drops, which causes the water to turn into steam. · This steam turns a turbine that is connected to a generator that produces electricity. The steam is cooled in a cooling tower and condensed back into water. [Example]

[0047] material: Stepanquat 200 is a 78.5% active solution of hexahydro-1,3,5-tris(hydroxyethyl)-s-triazine commercially available from Stepan Corp.

[0048] ST-O40, ST-30, ST-OV4, PGM-ST, ST-C, ST-V3, and MT-ST are colloidal silica products commercially available from Nissan Chemical America Corporation.

[0049] Organosilanes, propylene glycol monomethyl ether solvent, NaHCO3, CuCl2-H2O, and glyoxal were purchased from Sigma Aldrich Corp.

[0050] Synthesis Example 1: 1000 mL of Snowtex® ST-30 (a hydrous alkaline colloidal silica dispersion, 30 wt. % SiO2 solids, 10-15% median particle size) from Nissan Chemical America Corporation was placed in a 2000 mL, four-neck glass reactor equipped with an addition funnel, a thermometer, a heating mantle connected to a voltage regulator, and a mixer equipped with a 2-inch diameter three-way valve mixing blade. Mixing was started at 150 rpm, and the silica sol was brought to 50°C. 49.98 g of aminoethylaminoethylaminopropyltrimethoxysilane (CAS#35141-30-1, Sigma-Aldrich) was weighed into the addition funnel. The addition funnel was attached to the top of the reactor, and the silane was slowly added to the stirring silica sol at a rate of 2 drops per second. After all the organosilane had been added to the reaction, the mixture was allowed to stir at 50°C for 3 hours. The finished surface treated alkaline silica was poured into 2 L Nalgene bottles for storage and use.

[0051] Synthesis example 2: 1.4 L of Snowtex® O-XS (aqueous acidic colloidal silica dispersion, 10 wt% colloidal silica with a median particle size of 5 nm) was transferred to a four-neck reaction kettle. 9.6 L of distilled water was also added to this vessel. 13.87 g of copper(II) chloride anhydrous (CuCl2-H2O, Sigma-Aldrich) was added to the reaction flask and dissolved at room temperature with gentle stirring. A stock solution of NaHCO3 (Sigma-Aldrich ACS reagent grade, ≥99.7%) ("Solution A") was prepared (47.04 g of NaHCO3 dissolved in 12.6 L of distilled water, final concentration 0.04 M). The stirring speed in the reaction vessel was increased to 9500 rpm to achieve vigorous mixing. Solution A was slowly added to the reaction via an addition funnel at 10–15 mL per minute. After complete addition of Solution A, the reaction was allowed to stir at room temperature for 30 minutes, and the contents were removed for storage and use.

[0052] Synthesis example 3: 450 g of Snowtex® PGM-ST (a solvent dispersion of acidic colloidal silica, 30 wt% SiO2 dispersed in propylene glycol monomethyl ether, median particle size 10-15 nm) was placed in a 1000 mL four-neck reaction flask. Similar to Synthesis Example 1, the reactor was equipped with a mixer, thermometer, and heating mantle / voltage regulator. 4.05 g of 3-mercaptopropyltrimethoxysilane (Sigma-Aldrich) was added to an addition funnel and attached to the reactor. The PGM-ST was brought to 50 °C with gentle stirring, and mercaptopropyltrimethoxysilane was added dropwise via the addition funnel at 1 drop / second until addition was complete. The reaction was held at 50 °C for 3 hours, and then the surface-treated silica sol was poured into a Nalgene container for storage and use.

[0053] Example 1, Comparative: A 1000 mL Nalgene bottle was charged with 300 g of distilled water, 300 g of propylene glycol monomethyl ether ("PGM") solvent, and 300 g of Stepanquat 200. The contents were thoroughly mixed by vigorously shaking the container for 30 seconds.

[0054] Example 2: A 1000 mL Nalgene bottle was charged with 300 g of distilled water, 300 g of propylene glycol monomethyl ether solvent, and 300 g of the fluid from Synthesis Example 1. The contents were thoroughly mixed by vigorously shaking the container for 30 seconds.

[0055] Example 3, Comparative: A 1000 mL Nalgene bottle was charged with 700 g of distilled water and 300 g of Stepanquat 200. The contents were mixed thoroughly by vigorously shaking the container for 30 seconds.

[0056] Example 4: A 1000 mL Nalgene bottle was charged with 300 g of distilled water, 300 g of ST-O40 (a hydrous acidic colloidal silica available from Nissan Chemical America Corporation), and 300 g of Stepanquat 200. The contents were thoroughly mixed by vigorously shaking the container for 30 seconds.

[0057] Example 5: A 1000 mL Nalgene bottle was charged with 300 g of distilled water, 300 g of the fluid from Synthesis Example 2, and 300 g of Stepanquat 200. The contents were thoroughly mixed by vigorously shaking the container for 30 seconds.

[0058] Example 6: A 1000 mL Nalgene bottle was charged with 300 g of distilled water, 300 g of ST-OV4 (a hydrous acidic hydrophilic surface-treated colloidal silica available from Nissan Chemical America Corporation), and 300 g of Stepanquat 200. The contents were thoroughly mixed by vigorously shaking the container for 30 seconds.

[0059] Example 7: A 1000 mL Nalgene bottle was charged with 300 g of distilled water, 300 g of the fluid from Synthesis Example 3, and 300 g of Stepanquat 200. The contents were thoroughly mixed by vigorously shaking the container for 30 seconds.

[0060] Example 8: A 1000 mL Nalgene bottle was charged with 375 g of an aqueous glyoxal solution (Sigma Aldrich, 37.5 wt %) and 625 g of ST-C (a hydrous alkaline colloidal silica dispersion partially surface-treated with aluminum oxide, available from Nissan Chemical America Corporation). The contents were thoroughly mixed by vigorously shaking the container for 30 seconds.

[0061] Example 9: A 1000 mL Nalgene bottle was charged with 375 g of an aqueous glyoxal solution (Sigma Aldrich, 37.5 wt %) and 625 g of ST-O40 (a hydrous acidic colloidal silica dispersion available from Nissan Chemical America Corporation). The contents were thoroughly mixed by vigorously shaking the container for 30 seconds.

[0062] Example 10: A 1000 mL Nalgene bottle was charged with 375 g of an aqueous glyoxal solution (Sigma Aldrich, 37.5 wt %) and 625 g of ST-V3 (a hydrous alkaline hydrophilic surface-treated colloidal silica dispersion available from Nissan Chemical America Corporation). The contents were thoroughly mixed by vigorously shaking the container for 30 seconds.

[0063] Example 11: A 1000 mL Nalgene bottle was charged with 375 g of aqueous glyoxal solution (Sigma Aldrich, 37.5 wt %) and 625 g of MT-ST (solvent-borne acidic colloidal silica with 30 wt % SiO2 and a median particle size of 10-15 nm dispersed in methanol, available from Nissan Chemical America Corporation). The contents were thoroughly mixed by vigorously shaking the container for 30 seconds.

[0064] Example 12: Comparison A 1000 mL Nalgene bottle was charged with 375 g of an aqueous glyoxal solution (Sigma Aldrich, 37.5 wt %) and 625 g of distilled water. The contents were thoroughly mixed by vigorously shaking the container for 30 seconds.

[0065] The MEA triazine concentration was kept constant for all inventive and comparative examples. Similarly, the glyoxal concentration was kept constant for all inventive and comparative examples.

[0066] H2S removal test Each test solution was weight-balanced with 300 g of total solution and placed in a container equipped with an overhead port to measure the HS content in the container headspace. The headspace port was connected to a Drager Pac® 3500 gas monitor (Dragerwerk AG & Co. KGaA). A 10% HS / 90% nitrogen mixture was bubbled through the test solution at a standard rate of 475 mL / min, and the solution was maintained at 22 °C while the HS content of the headspace was monitored. A reading of 0 means that the sensor detected no HS in the flowing gas stream after the gas had passed through the test solution. The HS content of the container headspace was continuously monitored once per minute. When the gas monitor reading reached an HS content of 40, the test example in the solution that reacts with HS was considered consumed, and the experiment was stopped. The time to the first HS reading and the time to complete HS breakthrough were recorded and compared with the control / comparative example.

[0067] Summary of results The minutes listed indicate the length of time the detector detected a value of "0" for H2S. The table is ordered from best to worst performance for H2S removal. [Table 1]

[0068] Remarks on the working example: 1. Example 1: This is a triazine control / comparison example using MEA triazine dissolved in a mixture of water and PGM solvent. This example performed very well, far better than the same concentration of MEA triazine alone dissolved in water. Without intending to be bound by this, it is believed that PGM may indeed be very beneficial in the triazine + HS reaction.

[0069] 2. Example 2 (amine functional SiO2 combined with triazine) performed significantly better than the comparative example, improving / delaying the time to initial H2S breakthrough and the time to final breakthrough (when the H2S reading reaches a level of 40% in the headspace above the sample).

[0070] 3. Example 3 is a triazine + water control and these times were used to compare against all triazine + nanosilica examples. Example 3 illustrates a standard field grade fluid of MEA triazine fluid for sour gas treatment.

[0071] 4. Example 4 (ST-O40, hydrous acidic silica + triazine) showed the best performance of all the triazine + nanosilica examples. Without intending to be bound by this, it is believed that the solid acidity of the acidic silica surface likely acts as a catalyst to make the triazine + H2S reaction more complete, significantly improving / delaying the time to initial H2S breakthrough and complete H2S breakthrough.

[0072] 5. Example 5 (copper functionalized nanosilica + triazine) showed relatively good performance in improving / delaying the time to initial HS breakthrough and complete HS breakthrough. This example is the only example of a transition metal functionalized silica (note that the aluminum present in Example 8 is a "post-transition metal" and therefore not considered a true transition metal).

[0073] 6. Example 6 (ST-OV4 + triazine) is a hydrous acidic silica functionalized with a hydrophilic organic surface treatment, commercially available from Nissan Chemical America. This example had slightly worse time to initial H2S breakthrough compared to the control (Example 3), but significantly improved time to complete H2S breakthrough.

[0074] 7. Example 7 (mercapto-functional nanosilica dispersed in PGM + triazine) showed a slight improvement in time to initial H2S breakthrough and a significant improvement in time to complete H2S breakthrough. Without intending to be bound by this, it is believed that mercapto surface functionality may interfere with polymer formation in the triazine + H2S reaction.

[0075] 8. Example 8 is ST-C (a hydrous alkaline colloidal silica with an aluminum oxide surface) combined with glyoxal. Compared to glyoxal alone, this combination of ST-C + glyoxal showed dramatic improvements in both time to initial H2S breakthrough and time to complete H2S breakthrough. The glyoxal + nanosilica example performed relatively well. Note that the aluminum present in Example 8 is a "post-transition metal" and therefore not considered a true transition metal.

[0076] 9. Example 9 (ST-O40 + glyoxal) performed significantly better than glyoxal alone.

[0077] 10. Example 10 (ST-V3, hydrous alkaline silica with hydrophilic organic surface treatment + glyoxal) showed very good performance compared to glyoxal alone.

[0078] 11. Example 11 (acidic silica dispersed in methanol) did not perform well, and this example produced the worst results of all. Without intending to be bound by this, it is believed that MT-ST completely deactivated the glyoxal from reacting with HSJ.

[0079] 12. Example 12 is a comparative example that is a solution of glyoxal and water only, with no added nanotechnology.

Claims

1. H from the stream ２ A method for removing S, comprising the steps of: c) one or more hydrous acidic silica nanoparticle compositions, wherein the hydrous acidic silica nanoparticles are not surface treated; and d) one or more triazine compounds adding The streams include an oil stream, a gas stream, CO ２ The method is selected from the group consisting of point source purification streams and geothermal energy system streams.

2. 2. The method of claim 1 wherein one of the triazines present is hexahydro-1,3,5-tris(hydroxyethyl)-s-triazine.

3. The method of claim 1 , wherein the stream is an oil stream.

4. The method of claim 1 , wherein the stream is a gas stream.

5. The stream is CO ２ The method of claim 1 , wherein the point source purification stream is a point source purification stream.

6. The method of claim 1 , wherein the stream is a geothermal energy system stream.

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