MXPA99006403A - A process for the production of a corrosion-inhibitor surfactant compound, with no emulsification tendency, and resultant product - Google Patents

Abstract

La presente invención se refiere al proceso para la producción de un compuesto químico orgánico inhibidor de corrosión para medios para medios alcalinos, del tipo fílmico, solubles en hidrocarburos y dispersable en agua, desarrollado para controlar la corrosión provocada por la presencia de diversos agentes agrsivos, tales como:ácido sulfhidríco,ácido clorhidrico, amoníaco y bisulfuros en plantas de refinación de destilación, que evita la tendencia a la emulsificacion de hidrocarburos en agua y que tiene la capacidad de actuar como tensoactivo en la interfase, particularmente en plantas hidrodesulfuradoras de turbosina. Se considera la tecnología que se proporciona como un avance notable en el campo de inhibidores de corrosión, ya que combina la protección fílmica para la corrosión con el rompimiento de emulsión y acondicionamiento de la interfase para promover un efecto nulo de emulsificación de fases.

Description

PROCESS FOR THE PRODUCTION OF A TENSITIVE COMPOUND INHIBITOR OF CORROSION, WITHOUT TRENDS TO EM ULSI FICATION, AND RESULTING PRODUCT DESCRIPTION TECHNICAL FIELD OF THE INVENTION The present invention relates to the process for the production of an organic chemical compound corrosion inhibitor for alkaline media, of the filmic type, soluble in hydrocarbons and dispersible in water, developed to control the corrosion caused by the presence of various aggressive agents, such as : Hydrogen sulphide, hydrochloric acid, ammonia and disulphide distillation refining plants, which avoids the tendency to emulsify hydrocarbons in water and has the ability to act as a surfactant at the interface, particularly in turbosine hydrodesulfurization plants.

The technology that is provided as a breakthrough in the field of corrosion inhibitors is considered, as it combines film protection for corrosion with emulsion breaking and interface conditioning to promote a zero effect of phase emulsification.

BACKGROUND OF THE INVENTION Corrosion is a physicochemical phenomenon that commonly occurs in metal equipment of the oil refining industry. Its effects have very important scopes that can cause various problems, such as unscheduled plant shutdowns, reduced production, increased maintenance costs, poor product quality, high operating costs, accidents and other undesirable consequences.

In the hydrodesulfurization process, a stream rich in hydrogen and a hydrocarbon with a high content of pollutants are mixed, which are passed through a heating train to be later fed to a reactor with a nickel-molybdenum catalyst in order that the olefinic, aromatic or naphthenic hydrocarbons are saturated with hydrogen and the polar hydrocarbons containing sulfur, nitrogen and oxygen in their molecules decompose to regenerate the hydrocarbon and lead to the formation of the following by-products: H2 R-SH W H9S + RH? H2 R-NH, w NH3 + RH? H2 R-OH W H, O + RH? H2 R-CI - > - HCl + RH where: R represents a variable chain alkyl radical.

The use of wash water and steam in the reaction, fractionation and depletion sections promotes the dissolution of these by-products and the formation of highly corrosive alkaline bitter waters (pH between 8 and 13). In addition, the combined presence of hydrogen sulphide and ammonia causes a new aggressive agent to arise: Alkaline pH H? S + NH, A ^ H + + HS - + NH4 + lon lon Bisulfide Ammonium Disulfide ions represent the main cause of corrosion in hydrodesulphurizing plants and cause problems of generalized corrosion and localized corrosion (pitting or pitting).

For the specific case of turbosine hydrodesulfurization plants, the use of corrosion inhibitors is essential to avoid the tendency to emulsify as this hydrocarbon is used as aviation fuel, a high content of emulsified water present in it. It can cause serious problems.

To avoid these problems, corrosion inhibitors formulated with one or more persistent film-forming active components are used to protect against the aggression of aggressive agents, which is applied at low dosage levels and, above all, which favor the total separation of hydrocarbons. processed and resulting bitter waters.

As background of the process of the present invention, we have the national patent with file number 925707, related to the composition corrosion inhibitor, filmic type, soluble in hydrocarbons and dispersible in water, useful to reduce corrosion caused by bitter gases in alkaline media containing high concentrations of ammonia, in hydrodesulfurization plants of naphtha, turbosine, diesel and vacuum gas oil, as well as in hydrodesulphurisation and catalytic cracking plants of vacuum gas oils; and the Russian patent SU 611410A1, which mentions the obtaining of a corrosion inhibitor for aviation fuels (turbosine), which contains in its chemical structure a secondary amino group and an ester group. These groups are not of strong polar character, which reduces their tendency to adhere to surfaces such as glass, a factor that is critical when performing the water tolerance test on gasolines and turbosinas, according to the ASTM-D-1094 method.

The development of the present invention for hydrodesulphurizing plants allows to increase the efficiency of inhibition to corrosion and to reduce the tendency to emulsification, for which it promotes an adequate separation of the processed hydrocarbons and the bitter waters produced in the process.

The present invention relates to the synthesis of a new chemical compound inhibiting the corrosion of metallic surfaces of the monoethoxylated cycloalkylamine type, directly applicable to the hydrodesulfurization process equipment of turbosine which is in contact with aggressive media of the alkaline type, whose Bitter waters from the separators of the reaction, fractionation and exhaustion sections have an alkaline pH, with high concentrations of hydrogen sulphide, ammoniacal nitrogen and disulphide ions.

The chemical compound object of the present invention aims to provide a high level of protection when used at continuous dosages in the range of 2 to 10 ppm, since it keeps the corrosion within the limits allowed in the aforementioned process.

On the other hand, this compound offers the advantage of not emusing the processed hydrocarbon stream and the bitter waters present, by acting as a surfactant in the emulsion and in the interface.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the synthesis of a new chemical compound corrosion inhibitor of the filmic type, soluble in hydrocarbon and dispersible in water, useful to reduce the corrosion of surface and by pitting produced by aggressive agents, particularly hydrogen sulfide, ammonia and disulphides in alkaline media in turbosine hydrodesulfurization plants in particular.

The chemical compound of the present invention is a monoethoxylated cycloalkylamine and will hereafter be referred to as IMP-ICCE-9606. It is an organic liquid, stable, transparent in color, characteristic odor, soluble in hydrocarbons and dispersible in water.

The functional groups of the molecule confer the following characteristics: The nitrogenous group possesses the quality of using its free electrons to carry out a chemical walk on the metallic surface and in this way give rise to the formation of protective film of corrosion. The oxygenated group allows the compound to act as a surfactant in the emulsion and in the interface, due to the polarity it provides to the molecule. The cyclic group does not cause the emulsification of the process currents, unlike a linear alkyl group that would cause this problem.

The inhibitor composition has a suitable viscosity and runoff temperature for easy handling and dosing, even at low temperatures.

Next, some examples that serve to illustrate the present invention are described, but do not limit the scope thereof.

EXAMPLES EXAMPLE No.1 In a stainless steel reactor provided with heating, cooling, stirring, nitrogen injection and vacuum system, 69 kg of cyclohexylamine are introduced, adding 35 g of anhydrous potassium hydroxide, pulverized technical grade.

The reactor is closed and pressed with nitrogen until reaching ± 3 Kg / cm2, defoaming on four occasions for the elimination of air and humidity, initiating the agitation and heating. The temperature of the reaction mixture rises gradually until reaching 110 ° C, then proceeding to the addition of 31 kg of ethylene oxide, continuing the temperature increase to a maximum value of 160 ° C, for two hours.

The neutralization of the catalyst is carried out by adding 37 g of anhydrous acetic acid technical grade, resulting in a material with the following characteristics: TABLE l IMP-ICCE-9606 TEST UNIT SPECIFICATION METHOD ASTM Specific weight 20/4 ° C 1298 0.91 - 0.93 Kinematic viscosity 25 ° C cSt 445 180 - 210 Temp. of freezing ° C 97 -37 maximum Temp. of inflammation ° C 93 50 minimum Nitrogen content% weight E-258 8 - 12 Viscous liquid appearance EXAMPLE No. 2 In the reactor described in Example No. 1, conditioned with a water vapor condensation system and an accumulator, 142 kg of monoethoxylated cyclohexylamine and 282 kg of oleic acid were charged.

The reactor is closed, stirring and heating the mixture to a temperature of ± 150 ° C, at which the production of water as a result of the esterification reaction is observed.

The amount of water produced is used to define the term of the reaction, obtaining a homogeneous product of the amino ester, crystalline type, with a low nitrogen content (3.45% weight).

EXAMPLE No. 3 Considering the importance of the adequate separation of the process hydrocarbons and the water used for the washing of the condensers of the reaction section (high pressure separator), as well as of the bitter waters of the dome section of the exhausting column and of the dome section of the fractionating column of the hydrodesulphurisation plant, the tendency to emulsification of the product IMP-ICCE-9606, of the amino ester mentioned in example No. 2, as well as other commercial reference products according to the ASTM-D-1094 method of water tolerance.

This test method determines the presence of water-soluble components in gasolines and turbosines and the effect of these components on the water-fuel interface.

By performing the test with agitation at room temperature and using a phosphate-based buffer solution, the change in volume of the aqueous layer, the appearance of the interface and the degree of separation of the two phases, which indicate the tolerance to the water, are determined. fuel water.

The test consists of using 100 ml graduated cylinders with a ground stopper, placing 80 ml of hydrocarbon with characteristics similar to the currents of the aforementioned processes and 20 ml of buffer solution with pH 7. Subsequently, the contents of the test tubes are agitated for a period of period of 2 minutes, at the end of which, it is left to rest for 5 minutes and the characteristics of separation of the phases and the condition of the phase are graded.

Using as turbosine test medium and a 50 ppm dosing of the products, the following results were obtained taking as a base of comparison the specification established for this fuel (Separation 2 max, Interphase 1b max.), Observing the best functionality in the IMP-ICCE-9606 product.

TABLE I * Reaction product of naphthenic acids and aminoethylethanolamine. ** Reaction product of C18 fatty acids and aminoethylethanolamine. *** Reaction product of monoethoxylated cycloalkylamine and oleic acid.

The interpretation of the reported results is indicated below in the following table: INTERFACE CONDITIONS Classification Appearance or Grade 1 Clear and clean 1 b Small, clear bubbles that cover no more than 50% estimated at the interface and have no particles, film, or fibers. 2 Inferred with particles, fibers or film. 3 Light foam or thin cream and fibers. 4 Dense fibers or heavy foam or both.

SEPARATION INTERVAL Classification Appearance or Grade (D Absence of all emulsion and / or precipitate in both phases. (2) Same as in (1) except small air bubbles or small drops in the organic phase. (3) Emulsions and / or precipitates either in the organic phase or in the aqueous phase or adhered to the walls of the specimen, excluding the walls of the organic phase.

As can be seen in Table No. II, the product IMP-ICCE-9606 and the product of the amino ester type show an excellent performance in both grades (1 in separation and 1 in interphase). Commercial reference corrosion inhibitors have an unsatisfactory performance in water tolerance.

EXAMPLE No. 4 To establish at laboratory level the behavior of the products mentioned in example 2 as corrosion inhibitors, the following tests were carried out: PROOF OF HERRUMBRE.

The behavior of the products was evaluated, according to the method ASTM-D-665, using as an organic test medium turbosine and a brine with approximately 0.5% salts, mainly sodium chloride, considering that in the hydrobosulfurization plants of turbosina, concentrations of ammonium salts are observed in the range of 2,000 to 4,000 ppm (1, 000 - 2,000 ppm of sulfides and a similar amount of ammoniacal nitrogen).

This evaluation allows to establish the capacity of inhibited mineral oils, to reduce the oxidation or rust in the ferrous parts in contact with water or saline solutions.

The test conditions are as follows: Temperature 38 ° C Time 4 hours Agitation 1000 ± 50 rpm Dosage of inhibitor 50 ppm The amount of salts used in this evaluation provides high severity, such as that observed in turbosine hydrodesulfurization plants The results obtained were the following: TABLE III PROOF OF INHIBITION TO CORROSION.

According to the NACE-ID-182 method, rotary equipment is used to evaluate the degree of protection offered by the inhibitors when a constant concentration of the same is maintained in the system, under conditions similar to those observed in hydrodesulphurisation plants.

The test conditions are as follows: Temperature 70 ° C ± 2 ° C Time 48 hours Test material Carbon steel Test medium * Turbosine * Oxygen-free brine, adjusted to pH 8.5 with 3,000 ppm of hydrogen sulphide, ammonia and cyanides. Dosage of 50 ppm inhibitor The results obtained in the test are shown below: TABLE IV The product IMP-ICCE-9606 shows good efficiency of corrosion inhibition and comparable performance in this regard with respect to the other types of compounds used commercially for this purpose. The notable difference is observed in the behavior of corrosion inhibitors in the tendency to emulsify, where commercial compounds have problems of phase separation and interface conditioning, while IMP-ICCE-9606 has an excellent behavior.

The conclusions derived from the experimental part of the development of the new corrosion-inhibiting chemical compound of the present patent description indicate that IMP-ICCE-9606 allows to achieve a high protection efficiency and does not produce a tendency to emulsify, due to the surfactant effect of its molecule.

Claims (6)

NOVELTY OF THE NATION - 5 Having described the present invention, it is considered as a novelty and therefore, the content of the following clauses is claimed as our property:

1. A process for the protection of a corrosion inhibiting surfactant compound, without tendency to emulsification, characterized in that it comprises reacting cyclohexylamine in an alkaline medium, with ethylene oxide, at temperatures between 110 and 160 ° C and neutralizing the mixture reactant, with an organic acid.

2. A process according to clause 1, characterized in that the alkaline medium 15 comprises an alkali metal hydroxide.

3. A process according to clause 2, characterized in that the alkali metal hydroxide is potassium hydroxide.

4. A process according to clauses 1 to 3, characterized in that the organic acid is selected from acetic acid and oleic acid.

5. A process according to clauses 1 to 4, characterized in that monoethoxylated cyclohexylamine is used.

6. A process according to clause 5, characterized in that the monoethoxylated cyclohexylamine is neutralized with oleic acid.