Method and composition to decrease iron sulfide deposits in pipe lines

Method and formula for reducing iron sulphide deposits in pipelines

Method and Composition to Decrease Iron Sulfide Deposits in Pipe Lines

Hello full description

Background of the invention

The invention relates to methods and compositions for reducing or removing iron sulfide deposits in or on the conduit of a gas stream. H2S (Hydrogen sulfide) is a naturally harmful contaminant of fluids that is encountered, for example, during the treatment of Oil or gas 0 The corrosive nature of hydrogen sulfide typically leads to the accumulation of particulate iron sulfide, which can easily become suspended in hydrocarbons along with suspension in glycol, salts and other contaminants, forming Deposits that can interact with the surfaces of connecting pipes such as pipelines. These deposits pose a major problem for the oil and gas industries because pipelines must be physically cleaned. In addition, iron sulfide deposits hinder accurate estimates of the structural integrity of the pipeline, which can be assessed by measuring machines known as scrapers. Smart. SMART PIGS There has been limited skills and equipment available for these techniques to reduce or remove iron sulfide present from pipelines. US Patent No. 5,820,766 in the name of Gevertz et al., for example, describes the use of inorganic bromate

Inorganic bromates or inorganic iodates oxidize fluid-entrained sulfides suspended in a fluid to solid elemental sulfur, which must be mechanically collected and then removed from the pipeline. The by-product of this mechanical cleaning process is dirt that may be flammable and must be disposed of in a designated place between the layers of the earth. US Patent No. 236 4370 on behalf of Ferguson discloses a method in which iron sulfide is removed from a gas stream by washing using a mixture of a hydrocarbon and water. The resulting aqueous phase containing the soluble particulate iron sulfide must be removed by, for example, additional natural and chemical treatment steps. See US Patent No. 61,531,000.

An exchange method, as stated in general chemical principles, is to dissolve iron sulfide in water. Iron (II) ions and iron (III) ions are generally relatively insoluble compounds in water at normal pH values, and these iron compounds begin to precipitate from an aqueous solution at pH values of 5 or more. For example, iron (II) precipitates from normal solutions at a pH of 7 and is oxidized to iron (III) hydroxide in the presence of oxygen. Therefore, the normal method for converting iron II or iron III from compounds that are insoluble in water to compounds that are soluble in water, is to treat the solid in an aqueous mixture using a strong mineral acid, which works to lower the pH. And thus dissolving the iron compound 0. On the other hand, in the case of iron sulfide II, this method leads to the generation of hydrogen sulfide, and if this is done in a sufficient quantity (greater than 437 cubic centimeters per liter at a temperature of 0 degrees Celsius), it is released as a toxic gas. From the solution. There is an additional disadvantage to the use of strong mineral acids

In cleaning pipelines, most of the pipes are made of steel or iron, and these metals are easily susceptible when attacked by strong acids, and thus this leads to corrosion, damage and rupture of the pipes. Furthermore, such an attack results in the production of hydrogen gas, which is flammable and explosive in air.

There is also another method for removing iron sulfide disclosed in the Patent Cooperation Agreement publication for Universal Patent No. 02/08127 which describes the use of aqueous compositions of tris(hydroxymethyI)phosphine or a corresponding phosphonium salt (for short, &THP&) having a pH of less or less. Much higher than normal pH. On the other hand, the publication of the Patent Cooperation Agreement for Universal Patent No. 27 81 02/0 reveals that the use of tris(hydroxymethyl)phosphine, at the pH required for the rapid complexation of iron sulfide, is fraught with practical obstacles that include the formation of an insoluble polymer. When tris(hydroxymethyl)phosphine is formed with ammonium as a co-reagent, the compound tris(hydroxymethyI)phosphine oxide is also oxidized and converted into uncomplexed tris(hydroxymethyl)phosphine oxide. In light of these problems, UPC Publication No. 02/08127 reveals that iron sulfide can be chelated by amino phosphonic acids and amino carboxylic acids in formulas with THP. According to what was published, the use of THP in the absence of ammonium ion or ammonium gives a catalytic effect to dissolve iron sulfide. Because acidic common reagents are expensive, on the other hand, they are not preferable to use when large quantities are needed to remove iron sulfide deposits present.

Accordingly, there remains a need in the art for an improved method for removing iron sulfide deposits today, which uses safe, readily available, inexpensive materials, requires minimal mechanical input, and avoids chemical hazards, such as polymeric precipitates, found in prior art methods.

General description of the invention

To remedy this and for other requirements, the present invention provides a composition obtained by a process comprising the incorporation of at least one compound having the formula (I)

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With at least one amine or an ammonium moiety of that amine in the presence of an aqueous solvent. In the formula ( It is in the range from about 6 to about 9. Also, the most preferable of all of the above is for the pH of the aqueous solvent to be about 8 0.

In another aspect, the present invention provides a method for reducing the level of iron sulfide in a conduit pipe. The method of the invention includes contacting the conduit with the composition described above, resulting in the formation of a second composition, and then the second composition is removed from the conduit. This method derives in part from the unexpected discovery that the formula readily dissolves iron sulfide.

Another aspect of the present invention relates to a composition including: tris(hydroxymethyl)phosphine (TRIS), at least one amine or ammonium radical thereof, and a solvent. solvent

This invention also provides a method for reducing the level of iron sulfide in the conduit pipe, in which the conduit is brought into contact with a composition of tris(hydroxymethyl)phosphine, as previously described, to form a second composition, and then the second composition is removed from the conduction pipe.

conduit

The present invention may be implemented in relation to a variety of delivery pipes, such as dry gas delivery pipes and processed fluid delivery pipes.

Furthermore, the present invention contains both a continuous supply of the compositions of the present invention and an intermittent supply, i.e. a batch process.

In one embodiment of the invention, the X anion of formula (I) is monoanionic, dianionic, or trianionic. Therefore, acceptable anions are selected, but not limited to: chloride, bromide, iodide, lower alkyl carboxylates, bisulfite, bisulfate, hydrocarbyl sulfonates, dihydrogenphosphate, nitrate, hexafluorophosphate, sulfate, sulfite,

, monohydrogenphosphate, and phosphate

The preferred anions contain chloride and sulfate, so the preferred structures of formula (I) are tetrakis(hydroxymethyl)phosphonium chloride, and

tetrakis(hydroxymethyl)phosphonium sulfate.

The amines which are particularly useful in the practice of this invention include, but are not limited to:

ammonium, alkylamines, dialkylamines, alkylenediamines, cycloalkylamines, and accordingly, the acids accompanying these amines are also effective. It is preferable that the amine be ammonium or alkylamine. It is more preferable for the amine to be ammonium or methylamine. The preferred conjugate acid is ammonium chloride.

The present invention typically involves the use of a solvent. In particular, for a composition and method that uses compounds of formula (I), the solvent is an aqueous solvent and the preferred solvents contain, but are not limited to, water and alcohols. A solvent may also include two or more solvents such as water and alcohol. The preferred alcohol is .methanol

For both the compounds of formula (I) and the compounds of tris(hydroxymethyl)phosphine along with their amines or ammonium derivatives, the relative amounts and concentrations used in accordance with the present invention can vary widely. According to one aspect of the invention, the amount of the formula (I) compound or the TRIS compound varies in the range from about 1% to

About 90% (w/w), preferably 5% (w/w), and the most

Preferably, the amount of amine or its ammonium derivative changes within the limits of about 0.05%.

(w/w) to about 2% (w/w) 0. All quantities depend on the total weight of the composition.

The relative quantities of the components of the formulations are adjusted according to the molecular volume ratio of phosphorus to nitrogen. For compositions that include one or more compounds of formula (I), this molecular volumetric ratio is based on the molecular volumetric quantity of phosphorus contained in the phosphonium ions of formula (I). For compositions containing the compound tris(hydroxymethyl)phosphine, the molecular volume ratio is based simply on the molecular volumetric amount of tris(hydroxymethyl)phosphine. In any classification of the composition, the molecular volume ratio between phosphorus and nitrogen can vary in the range from about 1:1 to About 1:15. It is preferable for the molecular volume ratio to be in the range from 1:1.5 to about 8:1, while the most preferred molecular volume ratio is 1:2.5.

Detailed description

The present invention effectively reduces iron sulfide levels in delivery pipes, such as processed fluid pipe lines and dry gas pipe lines. Iron sulfide can be in a gas bar or, for example, on the surface of a gas stream conduit. A conduit that retains iron sulfide or contains iron sulfide must be placed in contact with the composition of the present invention, so that the iron sulfide is a complex, soluble compound that can be easily removed from the conduit. The invention is carried out at a pH value equal to the normal value or at a value close to it, and thus the pipes or any other connecting pipes are not corroded.

Composition:

The compositions of this invention are particularly effective in converting iron sulfide into a complex compound or in dissolving iron sulfide. According to one aspect of the present invention, this result can be easily achieved by placing one or more compounds of formula (I) in a mixture with at least one amine or with the ammonium moiety of such amine. Anion X balances the total positive charge

For one or more:-

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Of phosphonium cations. Typically, N in the formula (I) is 1, 2, or 3. Thus, X is typically monoanionic, dianionic, trianionic, or trianionic, respectively.

While any conventionally obtained Therefore, suitable monoanions contain halides such as chloride, bromide, and iodide.

The invention also intends to include lower alkyl carboxylates, where the expression &amp; lower alkyl refers to a straight or branched alkyl group containing a number of carbon atoms ranging from one carbon atom to six carbon atoms. Examples of lower alkyl carboxylates include:

lower alkyl carboxylates are methyl carboxylate (ie, acetate), ethyl carboxylate, and

Propyl and iso-propyl carboxylates. Other monoanions contain sulfur-based anions such as bisulfite, bisulfate, and hydrocarbyl sulfonates.

Hydrocarbyl sulfonates are anions with the formula RS(O)2O, where R is an aryl or lower alkyl group. Examples of hydrocarbyl sulfonates include, but are not limited to, methylsulfonate, benzenesulfonate, paratoluenesulfonate, and isomers of xylenesulfonate. And there are still monoanions

Another suitable product contains nitrate and hexafluorophosphate.

Dianions X contains sulfate, sulfite, and monohydrogenphosphate. Phosphate is the accepted trianion.

Compounds of formula (I) are commercially available or can be obtained traditionally by well-known synthetic methods. For example, particularly favored Formula I compounds are tetrakis(hydroxymethyl)phosphonium sulfate and tetrakis(hydroxymethyl)phosphonium chloride, both of which are available commercially, for example, from Rhodia (Cranberry, NJ). Nippon Industries (Tokyo, Japan) and Cytec Industries

((Mobile, AL

Tetrakis(hydroxymethyl)phosphonium sulfate is normally available as an acid solution

Water has a pH ranging from 1 to 4. Other compounds with the formula can be prepared

(I) The X anions are directly electrolyzed by the well-known reaction between phosphine and formaldehyde in the presence of aqueous HX as described, for example, in the procedure described in US Patent No. 4,044,055 by Katz et al. The amine or ammonium derivative that combines with one or more compounds of formula (I) can be selected from a group of different amines and conjugated acids. It is preferable but not essential that when the amine or its conjugate acid is a solid, it must be soluble in the solvent used in the composition according to the present invention. Likewise, when the amine or its conjugate acid is a liquid, it is preferably miscible with the solvent. Ammonium is one of the preferred amines.

Primary amines, for example alkylamines, are particularly effective in applying this invention in practice. Examples of alkylamines include, but are not limited to, methylamine, ethylamine, normal- and iso-propylamines, and -normal- and tert butylamines. Other primary amines are investigated over alkylenediamines, such as for example: l,2-diaminoethane and 1,3-diaminopropane. There are still other typical primary amines represented by cycloalkylamines, such as, for example, cyclopropylamine, cyclobutylamine, cyclopentylamine, and cyclohexylamine.

Ammonium derivatives can also be used for these amines. The ammonium derivative is the conjugate acid of amine. The conjugate acid of the amine is obtained by the traditional addition of an acid to this amine. Suitable acids contain inorganic acids, such as, for example, HCI acid, HBr acid, and HI acid, and organic acids, such as, for example, carboxylic acids. Therefore, the present invention uses a group of ammonium derivatives. Particularly preferred ammonium derivatives include ammonium chloride, ammonium nitrate, cethlammonium chloride, and methylammonium chloride.

According to certain embodiments of this invention, the composition is made by combining suitable amounts of at least one compound having the formula (I) and at least one amine or ammonium derivative of such amine in the presence of an aqueous solvent. The order of adding reagents can be changed, although it is preferable to add an amine or ammonium derivative to the solution of the formula compound (I), where the pH has been adjusted as described later.

Particularly preferred solvents contain water and alcohol. Alternatively, mixtures of water and alcohol can be used. Examples of alcohols include methanol and ethanol

And isopropanol.

In preferred embodiments, the amount of the compound having formula (I) is about 5% (w/w), or as little as 1% (w/w), depending on the total weight of the composition. The adequate amount of the amine or ammonium derivative varies from about 0.05% (w/w) to about 2% (w/w) depending on the total weight of the composition.

The pH of the highly prescribed mixture is adjusted to a value ranging from about 4.5 to about 1.0. Alternatively, solid compounds with formula (I) or their dilute solutions can be dissolved in an aqueous solvent whose pH has already been adjusted in the range from about 4.5 to about 10. In either case, adding the appropriate acid or base will produce the desired adjustment to the pH. Suitable acids contain hydrochloric and sulfuric acids. Suitable bases contain sodium and potassium hydroxides and organic bases such as triethylamine. For models that use commercially available aqueous solutions from:

tetrakis(hydroxymethyl)phosphonium sulfate, its pH must be raised. This is achieved by adding a suitable base to the mixture. The pH can be maintained at the required value by using a pH-regulating substance. In the Namonji procedure, acetic acid at a concentration of 0.1 molar is dissolved in less than 0.5 liters of water, and the pH of the product is adjusted to be 5 by adding sodium hydroxide at a concentration of 2 molars. The mixture is diluted with water to a volume of approximately 1 liter, then repeated. The pH is adjusted to be 5 using sodium hydroxide, and finally the volume is adjusted to be 1 liter. Alternatively, sodium or potassium acetate and acetic acid can be used so that the total amount of acetate ion from any source is 0.1 mole, and the solution is diluted to a , It arrives The volume is about 1 liter, then the pH is adjusted to 5 using acetic acid, and then the solution is diluted until its volume reaches exactly 1 liter. Other pH-regulating substances can be used, such as phosphate and citrate, to give a pH in

As regulating materials for nitriloacetic acids, the required field. In addition, nitrilotriacetic acid (NTA) can be used, and typical acids contain: Hydrogen pH

ethylenediamine-N,N,N',N'-tetraacetic acid (EDTA).

As previously stated, the present invention is generally effective when forming complex iron sulfide compounds over a wide range of pH. The inventor discovered that the rate of formation of a complex compound of iron sulfide increases with increasing pH. Therefore, the preferred pH is in the range from about 6 to about 9, and the most preferable pH is about 8. For clarification purposes, in laboratory experiments using an aqueous solution of FeSO4 at a concentration of 0.015 M, NH4+ at a concentration of 0.03 M, and tetrakis (hydroxymethyl)phosphonium sulfate at a concentration of 0.06 M, its pH was regulated to be 4.5, the rate of formation of the complex compound was For iron at a temperature of 22 degrees Celsius, it is half an hour, and the rate decreases to 0.01 hours for a similar solution at a pH equal to 5. For the purposes of these measurements, the rate is defined as the time required to raise the absorbance of the solution at 500 nm to 1. Without wanting to adhere to any special theory or principle, the inventor believes that compounds of formula (I), especially when we are exposed to aqueous solutions that have a high pH, give the compound (tris(hydroxymethyl)phosphine (TRIS). Therefore, a suitable method is used to produce the compound ris(hydroxymethyl)phosphine by adjusting the pH of an aqueous solution of tetrakis(hydroxymethyl)phosphonium sulfate to the value 8 by adding sodium hydroxide or potassium hydroxide, where 95% of the phosphorus is

The resulting solution in the form of TRIS is soluble in water. This transformation has been described in art. Look:. 553 (1962) 32 KA Petrov et al., Zhurnal obshchei Khimii Alternatively, tris(hydroxymethyl)phosphine can be synthesized by the reaction between potassium tetrachloroplatinate formaldehyde and phosphine. See US Patent No. 3030421 by Reuter et al. Tris(hydroxymethyl)phosphine is also commercially available, for example, from Strem Chemical:

Strem Chemicals, Inc. (Newburyport, MA) Another embodiment of this invention, the composition of tris(hydroxymethyl)phosphine, is derived in part from the startling discovery that the products of the reaction of tris(hydroxymethyl)phosphine with at least one amine or ammonium derivative moiety In particular, they are effective scavengers for iron sulfide in the conduit. According to the present invention, the amine or ammonium derivative thereof, as described above, combines with Tris(hydroxymethyl)phosphine in a solvent to form a solution. If the ammonium moiety is used in an aqueous solvent, it is preferable, but not necessary, to raise the pH of the solution.

The composition can be prepared by following two primary methods. In one embodiment, Tris(hydroxymethyl)phosphine is first prepared from an aqueous solution of a compound of formula (I), such as for example tetrakis(hydroxymethyl)phosphonium sulfate or TRIS chloride, following the known previously established method. The resulting solution containing...

The tetrakis(hydroxymethyl) phosphine is directly combined with the amine or ammonium moiety of a special d amine or solutions thereof, to form the composition. In an exchange model, a solution of pure tetrakis(hydroxymethyl)phosphine in a solvent may be combined with an amine or ammonium radical.

It is preferable that the amine be ammonium or a first amine such as methylamine or ethylamine. Methylamine is the most preferred. The preferred solvents are those that dissolve tris(hydroxymethyl)phosphine. Polar solvents, such as for example alcohols or mixtures of alcohols with water, are the preferred solvents. In preferred embodiments, the composition contains tetrakis(hydroxymethyl)phosphine in an amount of 5%

(w/w), or in a small amount up to 1% (w/w), based on the total weight of the composition.

The appropriate amount changes amine or. Its ammonium derivative ranges from about 0.05% (w/w) to about 2% (w/w) depending on the total weight of the formulation.

The methods and compositions of this invention are effective for a range of relative quantities of compounds of formula (I) or tris(hydroxymethyl)phosphine as well as of its amine or ammonium derivative. The molecular volume ratio phosphorus, content in phosphorus ions, content in phosphonium ions for formula (I) or in the TRIS compound, to nitrogen in the amine or ammonium derivative, can vary from about 1:1 to about 1:15. The preferred molecular volume ratio is in the range from about 1:1.5 to about 8:1. It is still more preferable for the molecular volume ratio to be about 2.5:1.

If the amine is ammonium or if the ammonium derivative is an ammonium salt (eg NH4CI), the polymeric precipitate may be observed during the optimum ratio determination period. However, even under conditions of optimum proportion and composition for the precipitate, the precipitate eventually dissolves to give a composition that shows a low but significant iron sulfide solubility. Alternatively, the product of the arrangement can be avoided without any detrimental effect on the final iron sulfide removal by using a molecular volume ratio of nitrogen:phosphorus higher than the optimum. In addition, the use of a primary amine, as previously described, does not result in a polymeric precipitation product. It thus offers a striking advantage over prior art formulations that result in deposition yields. Furthermore, if alkylamine and ammonium are used at the same time, the energy of ammonium without the formation of a precipitate is improved within the pH range useful for the present invention where solutions are produced that are also effective in dissolving iron sulfide. Thus, these compositions of the invention comprising alkylamines offer the advantage of forming a complex of iron sulfide bound to a surplus of water which is rationalized with ammonium. The compositions of the present invention optionally include one or more additives that make the compositions usable in many types of connecting pipes, where iron sulfide deposits present a problem. The additives contain surfactants and biocides, such as, for example:

(glutaraldehyde and 2,2-dibromo-3-nitrilopropionamide (DBPNA), water derivatives, demulsifiers, anti-scale materials, anti-corrosion materials, and anti-peeling materials

diethylhydroxylamine (DEHA)) such as for example oxygen foams and scavengers

and consolidation factors.

anionic surfactants on ionic substances Surfactants refrigerator surfactants contain surfactants and acid-alkaline substances surfactants and surfactants, which generally contain a moiety consisting of non-ionic substances, non-ionic substances, and an alkyl group such as, for example, a hydrophilic group, water, and non-ionic substituents. Water, a cyclic aryl group, a cyclic alkenyl group, an alkyl group, an alkenyl group, and a propyl group contain a number of carbon atoms. The arylalkyl and alkaryl group range from 6 carbon atoms to 4 2 atoms. Carbon, preferably from 10 carbon atoms to 20 carbon atoms, and preferably more than 12 carbon atoms to 18 carbon atoms. Waterless substitutes and polysiloxanes also contain polymeric parts, such as e.g.

polyoxypropylenes

Surfactants contain slightly anionic salts that dissolve in water. Examples of substances include, for example: mono-esters of sulfuric acid or sulfuric acid alkylbenzene sulfonates, alkyl sulfates, alkyl ether sulfates, olefin sulfonates, alkane sulfonates, alkylphenol sulfates, alkylphenol ether sulfates, alkylethanolamide sulfate, alkylethanolamidether dulfate, and alpha sulfo fatty acids

corresponding, each of which contains a number of carbon atoms ranging from 6 carbon atoms, esters or

to 24 carbon atoms.

Other typical anionic surfactants are soapy substances such as, for example:

linoleates, alkyl ether carboxylates, palmitates, resinates, oleates, and stearates; and alkyl sulfosuccinates

Such as for example:

sodium di-2-ethyexylsulfosuccinate and sodium dihexylsulfosuccinate, acyl taurides,

isethionates, alkyl ether sulfosuccinates, acyl sarcosinates, and alkyl sulfosuccinates.

: Surfactants are anionic and can be the substance

anionic phosphate ester, alkyl phosphonate, alkyl amino- or iminomethylene phosphonate.

Each of these surfactants generally contains at least one hydrophobic substituent, as described above. Ether-containing surfactants contain one or more of the following groups:

glyceryl, oxyethylene, oxypropylene, and oxybutylene. The preferred surfactants, anionic salts are sodium substances, while sodium salts are...

Others of commercial importance contain those salts that include: And there are still other salts that can be used. lithium, potassium, calcium, and magnesium

: These are salts that contain

ammonia, monoethanolamine, diethanolamine, triethanolamine, lower alkylamines, alkyl- and hydroxyalkyl-phosphonium.

Non-ionic surfactants contain:

alcohols and tertiary acetylinic glycols, add a group of polyethoxylated mercaptans, add a group of polyethoxylated and carboxylic acids, add a group of polyethoxylated amines, add a group of polyethoxylated hydroxyalkyl amides, add a group of polyethoxylated alkyl phenols, add a group of polyethoxylated glyceryl esters, add a propoxylate group, and derivatives to which a propoxylated group is introduced, or A mixture of derivatives to which a propoxylate group was added. Derivatives to which a propoxylate group was added Propoxylated to those previous compounds. Polymeric non-ionic surfactants contain block copolymers of polyoxypropylene and polyethylene, and copolymers of polyoxybutylene and polyoxyethylene, or polyoxybutylene and polyoxypropylene.

Acid-alkali surfactants contain any surfactant compound that includes a moiety that is not afflicted with water, such as, for example, an alkenyl or alkyl group.

It contains a number of carbon atoms ranging from 6 carbon atoms to 2 carbon atoms, and part

Water does not contain an amine group, quaternary ammonium group, carboxylate sulfate, or sulfonic acid. Typical acid-alkaline surfactants contain betaines, such as for example imidazoline betaines. It contains other materials

The alkyl amine ether sulfates, sulfobetaines, quaternary amine or imidazoline sulfonic acids converted to quaternized and salts thereof. There are still suitable surfactants that contain surfactants with dipolar ions, such as, for example:

N-alkyl taurines and carboxylate amido amines. Specific examples include, but are not limited to:

2-tallow alkyl, 1-tallow amido alkyl, l-carboxymethyl imidazoline and 2-coconut alkyl,

and N-carboxymethyl-2-(hydroxyalkyl)imidazoline.

The cationic surfactants useful in the present invention include alkyl ammonium salts containing at least 8 fatty carbon atoms, preferably containing a number of fatty carbon atoms ranging from 1 to 30 carbon atoms, and preferably containing a number of fatty carbon atoms. The lipid carbon ranges from 2 1 carbon atoms to 2 4 carbon atoms. Particularly preferred cationic surfactants are tetraalkylammonium and tetraalkylammonium salts. Typically, a cationic surfactant will contain one or more fatty chains, each containing a number of carbon atoms ranging from 8 to 2 carbon atoms, and two or three short alkyl groups, each containing a number of carbon atoms. It ranges from one carbon atom to four carbon atoms. Particular examples include dodecyl trimethyl ammonium salts and benzalk'onium salts containing one long alkyl group and two short alkyl groups.

Other useful cationic surfactants contain N-alkyl pyridinium salts, where the alkyl groups contain a number of carbon atoms ranging from 8 carbon atoms to 22 carbon atoms, and it is preferable for the alkyl groups to contain a number of carbon atoms ranging from 10 carbon atoms. To 02 carbon atoms.

The cationic surfactant can also be an alkaryl dialkylammonium salt. Each alkyl group contains a number of atoms

The lipid carbon ranges from one to four carbon atoms, and is alkaryl groups; For example, it is an alkyl benzene group containing a number of atoms

Carbon ranges from 8 carbon atoms to 22 carbon atoms. There is still another class of cationic surfactants containing alkyl imidazoline salts, such as for example:

alkyl methyl hydroxyethyl imidazolinium salts. Examples include alkyl methyl -2 hydroxyethyl imidazolinium salts, alkyl benzyl hydroxyethyl imidazolinium salts, and

alkyl-l-alkylamidoethyl imidazoline salts. There are amines and amines in particular that are useful as cationic surfactants. These are formed by the reaction of a fatty acid, ester, glyceride, or amide, which form derivatives thereof, with di- or poly-amine. Typical polyamines are ethylene diamine and diethylene triamine.

Cationic surfactants contain an anion, which can be any anion that imparts water solubility to the surfactant. Suitable anions contain, but are not limited to, those anions X in formula (I) described above. The previous surfactants also contain their derivatives that have been polyfluorinated. Particularly preferred surfactants in this category contain alkyl sulfate (polyfluorinated) and quaternary ammonium salts (polyfluorinated).

The surfactants in this invention are those substances that can ideally be used as wetting agents. Wetting agents reduce the surface tension between water and a solid surface that is not familiar with water, such as, for example, the inner surface of a pipeline. The amounts of surfactant in the compositions of the present invention can vary over a wide range. Typically, the surfactant is present in an amount proportional to the weight of the formula (I) compound or the TRIS compound, where the ratio between them ranges from about 1:50 to about 200:1, and it is preferable for the ratio to be in the range from about 1:20 to about 100: 1 It is most preferable for the ratio to be within the limits of approximately 1:1 to approximately 50:1. In particular, it is preferable for the ratio to range from about 2:1 to about 15:1. The anti-scale and corrosion-resistant materials that are useful in this invention include, but are not limited to, phosphonates such as, for example:

1-hydroxyethane-1,1,-diphosphonate, polymaleates, polyacrylates, polymethyacrylates,

Polyphosphates, phosphate esters, soluble zinc salts, nitrates, sulfites, benzoates, tannin, ligninsulfonates, benzotriazole and mercaptobenzothiazole amines, imidazolines, and quaternary ammonium compound resins.

It contains antimicrobial agents. Typical polyacrylamide class of consolidation agents are dispersions and derivatives to which a group of silicones and acetylinic diols are introduced to form foams. Typical biocides contain tin and polyethoxylated compounds. The compositions of this invention may also contain non-surfactant bioenforcing agents, such as those Substances described in US Patent No. 4,778,813.

Non-surfactant biological enforcement agents include:

poly[hydroxyethylene(dimethyhminio)ethylene(dimethyhmin dichloride),

poly[hydroxyethylene(dimethyliminio)-2-hydroxypropylene(dimethyliminio)me-thylene dichloride], and N-[3-(dimethyIammonio)propyl]-N-[3-(ethyleneoxyethylenedimethylammonio)pr- opyl]urea dichloride

An alternative class of non-surfactants are hydrotropism agents which, at concentrations of about 1% or more, increase the solubility in water of slightly or moderately soluble solutes. Typical water tropism agents are glycol ethers that dissolve in water, such as for example diethylene glycol monomethyl ether. Other water tropism agents contain lower alkylaryl sulfonate salts

sodium, potassium, ammonium.

When the composition of the present invention contains a non-surfactant bio-rescue agent, said agent may be used in an amount of about 50% (w/w) and it is preferable that the agent be used in an amount of about 0.2% (w/w). It is more preferable that The amount should be less than about 10% (w/w), and it is most preferable for the amount to be less than about 5% (w/w), based on

The weight of the formula composition (I) or the tris(hydroxymethyl)phosphine compound in the formula. It is preferable that the foregoing additives be combined with preformed compositions according to the present invention. For example, a compound of formula (I) or tris(hydroxymethyl)phosphine is combined with an amine or ammonium moiety, as described herein

Previously. One or more additives are then added to the resulting formulation. Additives may be added as pure compounds or as commercially available preparations of those compounds, such as aqueous solutions.

The compositions of the present invention may be prepared in advance and stored until needed. The formulations are moderately sensitive to oxygen. Therefore, it is preferable but not essential that the installations be purged using an inert gas and stored in an inert gas atmosphere; Like for example dinitrogen. Alternatively, the compositions may simply be stored in an inert gas atmosphere or even in tightly closed, nearly full containers; This is to reduce the volume of air in the folded space of the container to the smallest possible amount.

How to reduce iron sulfide levels

The methods of the present invention are highly effective in dissolving iron sulfide. The desired goal is achieved by touching a conduit pipe containing iron sulfide with a composition of this invention to form a second composition, and then the second composition is removed from the conduit pipe.

These methods are used with a wide range of types of pipes that are contaminated or otherwise clogged due to the formation of iron sulfide deposits. Connecting pipes contain any container that carries water, gas, or other fluid. Examples of connection pipes include, but are not limited to, pipelines, valves, filters, filtration media, tanks, and storage facilities. Connecting pipes that are particularly relevant to the oil and gas industries are connecting pipes that can carry dry gas, treated fluid, or both. Therefore, a special advantage of the present invention in this regard is that the pH of the compositions introduced into the pipelines is adjustable and controllable, thus leading to ease of treatment and maintenance as well as ease of disposal of the compositions. The present invention also aims to treat water and aquatic systems, such as, for example, tank water that is contaminated with iron sulfide. In this regard, the iron sulfide removal process will reduce the tendency to clog the filtration media by the formation of iron sulfide and thus reduce the need for treatments with conventional strong mineral acids which typically lead to concomitant attack on iron pipes and other systems containing iron. .

The compositions of this invention may be inserted into connecting pipes by any means or combination of means necessary to place the fittings inside a conduit with iron sulfide deposits present. It is possible for the installations to be inserted continuously or intermittently, that is, in batches, into operating gas pipe lines or fluid pipe lines, for example. Alternatively, batch insertion is effective for pipelines that are not in operation, and have been temporarily taken out of service for cleaning purposes. Industrial procedures include pipe abrasion cleaning, which is effective for pipeline treatment. Fittings can be inserted into pipelines by following a traditional pipe cleaning procedure with scraping to remove remaining iron sulfide. Additionally, formulations can be used in continually evolving treatment of these pipelines to keep iron sulfide levels low.

While the use of any special composition according to the present invention is effective in removing iron sulfide from conductive pipes, the optimum molecular volume ratio of phosphorus to iron for a given composition is about 5:1. The optimum molecular volume ratio may depend in some way on the amine or ammonium derivative contained in the composition, and is easy to determine by conventional experiments. For example, a ratio between phosphorus and iron of 4:1 is particularly effective for combinations of tris(hydroxymethyl)phosphine and ammonium, which give solutions that appear to be a color ranging from pink to bluish-red, depending on the concentration of iron. sulfide, which is transformed into a complex compound. The ratio of phosphorus to iron, which reached 1:5.1, is the most effective ratio for formulations of tris(hydroxymethyl)phosphine methlamine, which typically give complex iron sulfide compounds whose color ranges from

The color is salmon orange (yellowish orange) to dark orange, brown, depending on the concentration of the iron sulfide that has been transformed into a complex compound. On the other hand, it can be done simply by using molecular volume ratios that differ from the optimal ratio, as both processes of transformation into the compound will occur. It is complex, as is the dissolution of iron sulfide, albeit at a slower rate. In any case, iron sulfide solutions that have been dissolved, once formed, become increasingly pale yellow in color as the iron slowly oxidizes when exposed to air, but nevertheless remains homogeneous. The following examples are provided to illustrate the present invention. On the other hand, it must be realized that the invention is not limited to the special cases or the details described in this example.

Example No. (1): A composition produced from:

Tetrakis (hydroxymethyl)phosphonium sulfate (THPS) and Ammonium Chloride. (a) Tetrakis (hydroxymethyl)phosphonium sulfate (THPS) is obtained commercially as an aqueous solution of 75% to 90% by weight with a pH change of less than 4. The following procedure yielded 1000 grams of an aqueous composition at a concentration of 5% capable of Converting iron sulfide into a complex compound, 66.6 grams of (THPS) at a concentration of 75% by weight (in water) and 0.5 grams of ammonium chloride were combined, and the resulting product was diluted using 0.9 grams of water, and the components were then mixed. A sufficient amount of an aqueous solution of 30% by weight of sodium hydroxide or potassium hydroxide was added to raise the pH to 6.5. The total weight of the product was brought to 0 0 0 1 grams by adding water, and then the pH was reset to 0. After dilution, it is possible to reset the pH slightly, if necessary, until it reaches the desired value.

In this example, water can be replaced with methanol in different amounts to produce solutions containing the least amount of water, which is 0%, and solutions containing the largest amount of water, which is up to 95%, depending on the total relative amounts of THPS and water in the solutions. Higher concentration formulations can be prepared simply by determining the amount of water or alcohol used to dilute the reaction solution

(b) Commercial quantities of the composition were prepared following this procedure. 26 gallons of tetrakis (hydroxymethyl) phosphonium sulfate were diluted as an aqueous solution at a concentration

75% until the quantity reached about 0.38 gallons using deionized water. The resulting acidic solution was adjusted to have a pH of 7.7 using aqueous potassium hydroxide at a concentration of 40%, and the volume was brought to 0.39 gallons using deionized water. After mixing well, ammonium chloride (0.47 lb) was added and the resulting mixture was dissolved well by stirring. The pH was adjusted to the required value of 7.7 using a small amount of aqueous potassium hydroxide at a concentration of 0.4%, and the resulting composition was stored in almost full sealed containers under an ideal curtain of nitrogen.

Example No. (2): A composition produced from:

Tetrakis (hydroxymethyl)phosphonium sulfate (THPS) and Methylamine

Following the procedure described in Example No. (1), Formulation . 9 mg of solution, and

(2) Adding 2 1 M of concentrated aqueous caustic potash to form tris(hydroxymethyl)phosphine (with a conversion rate of 95%) with a pH of 7.7, and (3) diluting the product with water until the volume reaches 0.1 mm, and ( 4) Add 0.263 grams of methylamine, and (5) mix the ingredients.

The molecular volume ratio between amine and tris(hydroxymethyl)phosphine in this mixture was 1:2.6.

Example No. (3): Determine the optimal ratio between the materials involved in the reaction and iron. The following determined values illustrate how the relative molecular volumetric amounts of TRIS and amine source influence the ideal formation of iron(II)sulfate complexes. In these determinations, water-soluble heptahydrate (iron(II)sulfate complex II) was chosen as the standard source. Suitable. Tris(hydroxymethyl) phosphine was produced using the general procedures that...

Described in Examples No. (1) and (2).

The complex formed from TRIS, ammonium, and iron II shows an absorbance maximum near 490 nm. To find the optimal ratio of substances involved in the reaction, the absorbance of the different compositions of the components that were converted into a complex compound was measured. The optimum molecular volume ratio for the compounds [TRIS, ammonium, and iron II] was observed as a ratio of 5:8:20.

A similar attempt using methylamine gave a complex compound with an absorption maximum at 473 nm, and an ideal ratio (in moles) of 5:10,5:26 as the ratio between [iron:methylamine:TOS(II)].

Such as No. (4) converting insoluble iron sulfide into a complex compound

Iron (II) sulfide was precipitated from an aqueous solution by combining a reversible iron (II) compound.

Soluble and soluble sulfide in equal molar ratios and in sufficient amounts until the solubility is exceeded

II) iron sulfide. In this example, a combination of 1.65 ml of iron (II

Sulfate heptahydrate with a concentration of 172,. Mueller with 1.65 ml of sodium sulfide solution

nonahydrate at a concentration of 0.172 M in a solution with a total volume of 50 ml, to precipitation.

25 grams of black iron sulfide II or a dispersed suspension, about 500 mg

iron (II) sulfide in every liter of solution.

(a) Converting iron sulfide into a complex compound in a dispersed suspension:

20 milliliters of the 5% aqueous composition by weight that was prepared in Example No. (2) was stirred with 25 milligrams of iron sulfide in an amount of water with a total volume of 0.5 milliliters. The ratio methylamine:TRIS was calculated and was 10:26. Iron sulfide (II) was dissolved at a temperature of 2 2°C at an initial rate ranging from about 0 0 8 1 parts per million per hour to about 33 parts per million per hour when either the composition or the iron sulfide became exhausted.

Alternatively, 20 ml of the aqueous composition in Example (1) was stirred with the dispersed suspension of iron sulfide. The iron sulfide was completely dissolved within 30 minutes, as confirmed by the steady increase in absorbance of the solution at about 500 nm. Formation of a complex compound of iron sulfide precipitate on a filter:-

The dispersed suspension of iron sulfide II, which had been prepared as previously, was filtered on a cloth filter by suction, and the cloth with the iron sulfide to which it was attached was placed in contact with 50 milliliters of pH-regulating citrate at a concentration of 0. 1 In water at pH 5 and 0 2 mM of the composition according to Example No. (1), and the components were stirred. The fabric filter was completely free of sediment in less than 2 hours, during which the absorption of the surrounding solution at 500 nm increased. Example No. (5): The dependence of the pH on the formed structures that convert Iron II into a complex compound:

This example shows that the compositions and methods of the present invention that use tetrakis(hydroxymehyl)phosphonium sulfate (THPS) depend on the pH value. pH

For each entry process in the following table, a raw solution is used containing FeSO4 (0.015 molar), NH4+ (0.030 molar), THPS (0.06 molar), and pH-regulating phosphate (0.1 molar) at a temperature of 22 degrees Celsius. Primary solutions are essentially colorless. The pH-regulating substance phosphate was used at a concentration of 0.1 M to stabilize the pH during each experiment.

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The results show that the conversion of iron sulfide into a complex compound occurs more quickly for formulations prepared from THPS at a high pH of 0. At high pH values that exceed 5, the conversion rates into a complex compound continue to increase, and at a pH value of 7 ,5 For example, the complete transformation into a complex compound is completed within a few seconds.

Example No. (6): Batch procedure using a cylindrical scraper bead. This example shows how to clean a pipeline containing iron sulfide deposits using a composition and method according to this invention.

A cylindrical scraper is launched into the pipeline and comes to rest at a certain position inside the pipeline. A sufficient amount of the aqueous composition that was prepared is injected as stated in Example No. (1); Into line 0, a second cylindrical scraper is launched, and a fluid column is formed between the two rakes, which will cover the entire circumference of the pipeline wall. The scraper bead is fired so that it moves at a speed of 6 miles per hour depending on the pressure control used to move the two scrapers. A third scraper can be fired with a carrier fluid for additional cleaning of any loose particles that were left behind after the previous cleaning. Samples can be taken to the future scraper to determine whether additional scraping cleaning is necessary or not. Example No. (7): Procedure without tightening the pipes 0

This procedure may be necessary for pipelines with serious iron sulfide accumulation or if the pipeline is not equipped with cylindrical scraper receivers and release devices. Some types of separation or stabilization vessels may be necessary above the line. An aqueous composition according to this invention is injected into the pipeline continuously before iron accumulates. Flow rate and pressure are monitored, and samples are taken when possible. The iron sulfide present is removed during the continuous flow of the composition through the pipeline.

Example No. (8): Performing scraping cleaning in batches

The aqueous composition is introduced, according to Example No. (1), in batches into the pipeline by feeding by gravity or by injection, depending on the internal pressure of the pipeline. Then, a cylindrical scraper is launched after the batch using the aqueous composition to move the solution along the line. To get better results, the scraper should move at a speed of 6 mph. Samples can be taken at the scraper receiver to determine whether additional cleaning by scraping is required. All sizes of the composition are based on the length of the pipe, its internal diameter, and the degree of danger of dirt and mineral masses that accumulate in the pipeline. The type of scraper can be chosen based on the degree of seriousness of the materials accumulated in the pipeline. Although the present invention has been described and explained with respect to preferred embodiments as well as the preferred use of those embodiments, it is not limited in that it is possible to make modifications and changes therein that are within the full scope of the invention as explained in the attached claims.