MXPA03011659A

MXPA03011659A - Composition for inhibiting corrosion based on bisimidazoline 2-oleic-2'-naphthenic.

Info

Publication number: MXPA03011659A
Authority: MX
Inventors: Maria Ruth Martinez Aguile Luz
Original assignee: Mexicano Inst Petrol
Priority date: 2003-12-16
Filing date: 2003-12-16
Publication date: 2005-06-20

Abstract

The present invention refers to a composition for inhibiting corrosion based on bisimidazoline 2-oleic-2'nephthenic, which is a bicyclic compound presenting in a first imidazoline ring as a C2 substituent an hydrocarbonated chain of 18 carbons with a double bond between the carbon atoms 9 and 10; and in the C2' of the remaining imidazoline ring a cyclohexyl. The aforementioned imidazoline rings are linked with an ethyl by tertiary nitrogen atoms. Said bisimidazoline is useful as an active principle for preparing the corrosion inhibiting composition, the same comprising isopropanol and xylene or naphtha, so as to be applied in low concentrations in atmospheric distillation towers containing heavy crudes, which are highly corrosive due to the high content of salts and heavy metals such as vanadium and nickel.

Description

CORROSION INHIBITORY COMPOSITION BASED ON BISI IDAZOLINE 2-OLÉICO-2'-NAFÉNÉNICA DESCRIPTION TECHNICAL FIELD The present invention relates to a corrosion inhibiting composition using a new mixed bisimidazoline with two different substituents having superior properties to inhibit corrosion with greater efficiency in the bitter waters resulting from the industrial oil refining plants.

BACKGROUND OF THE INVENTION Heavy crude oil has higher amounts of corrosive materials such as water and salts such as sodium chloride, calcium chloride, magnesium chloride, hydrogen sulphide in addition to organic sulfides and disulfides and coordinated vanadium compounds that cause corrosion damage in refinery equipment, which is why it is necessary to look for new formulations that inhibit corrosion to extend the useful life of the equipment.

This behavior of greater corrosive capacity makes necessary the design of more efficient corrosion inhibitors and with an improved rheological behavior, that is to say that no emulsions or suspensions are formed with the chemical products used in the refining of the crude oil, besides complying with the protection functions.

Mexican patent MX 133364 of publication date of September 11, 1976, where imidazolines substituted with a hydrocarbon chain of 16 to 18 carbon atoms are present in the C2 atoms and a 1-H-imidazole protonated in N2 of the imidazolidine, that is, that the structure has an imidazoline ring and an imidazole ring.

In US Patent 4,482,724 of publication date of November 13, 1984 assigned to Hoechst Aktiengesellschaft, it mentions the use of bisimidazolines with dimerized fatty acid chains of 22 to 42 carbons and with substituents of hydrogen, methyl, ethyl, benzyl and radicals polyethoxylates that are used as demulsifiers and corrosion inhibitors. This American patent represents the closest prior to the structure of the base compound of the formulation of this invention, however, the substituents and raw materials from which the compounds protected by US Pat. No. 4,482,724 are made are different. , the radicals protected by it are also different.

The Mexican patent application No. of File PA / a / 2003/011620 of filing date on December 15, 2003, whose inventors are the undersigned, refers to mixed bisimidazolines as active principles of corrosion inhibiting compositions that present in the structure of the imidazoline ring two identical or different substituents which may be hydrogen, oleyl, naphtenyl, dodecylbenzenesulfonyl, abieyl or dehydroabieyl. Preferably, protection of the active ingredients with new chemical structures, such as 2,2'-oleic bisimidazolines, and a bisimidazoline - [(1-aminoethyl) -imidazoline] -1,6-hexanoic which is abbreviated (bis- 6-hex).

The present invention relates to the preparation of a composition having as an active principle 2-oleic-2'-naphthenic bisimidazoline to inhibit corrosion. This new composition has a greater character dispersible in water to guarantee that the inhibitor acts in both phases, both in the hydrocarbon and in the bitter waters resulting from the industrial oil refining plants and solves the problems of formation of emulsions and / or suspensions at the water-hydrocarbon interface.

Therefore, an object of the invention is to prepare a composition suitable for 2-oleic-2'-naphthenic bisimidazoline to optimize its corrosion inhibiting properties by using it at lower concentrations (10 to 20 ppm) than those used in other compounds reported in the inhibition of corrosion in atmospheric distillation towers with heavy crudes that tend to present more corrosion problems.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composition for optimizing the application of 2-oleic-2'-naphthenic bisimidazoline which belongs to the family of imidazolines and which is a new bicyclic compound linked by an ethyl bridge between nitrogens 1 and 1 'of the imidazoline rings which in turn have in C2 an oleyl group, and in C2' a naphtenyl group.

The composition of the present invention, is prepared with the 2-oleic-2'-naphthenic bisimidazoline with xylene and isopropanol to be used at lower concentrations (10 to 20 ppm) than those used in other compounds reported in the inhibition of corrosion in atmospheric distillation towers with heavy crude oils for diesel and gasoline streams.

The active principle of the inhibitor composition of the present invention is a new bisimidazoline, the result of theoretical studies of molecular modeling with theoretical chemistry programs that allow to predict its reactivity and with it the way in which they have to adhere to the stainless steel surface. They have to protect more efficiently. Below is the new structure with structure 1, from the beginning. active as a component of the composition of the present invention: The 2-oleic-2'-naphthenic bisimidazoline has two imidazoline rings linked by an ethyl bridge and has on the C2 of one of the imidazoline rings an hydrocarbon chain of 18 carbons with a double bond between the carbons 9 and 10 and in the other ring of imidazoline has in C2 'a cyclohexyl. Said molecule has a high protective capacity as a corrosion inhibitor, and has a better dispersibility in both diesel and gasoline and in the bitter waters present in the primary distillation plants. This better miscibility behavior in the aqueous and organic phases allows solving the problems of hydrocarbon-water-inhibitor emulsion formation. Percentages greater than 90% of the corrosion protection efficiency of the synthesized inhibitors were obtained, with a concentration 20 times lower than that on average used with commercial inhibitors.

EXAMPLE General procedure for the preparation of the bisimidazoline 2-oleic-2'-naphthenic which will be the active principle of the composition that functions to inhibit corrosion, object of the present invention. According to the present invention, 1 mole gram (the equivalent to the molecular weight considered in grams) of oleic acid and 1.0 gram of naphthenic acid are heated, with one gram mole of triethylene tetramine in xylene, contained in a reaction equipment with separator. of water until 2 ounces of water have been removed. The xylene is then removed by distillation and the obtained bisimidazoline is stored in a hermetically sealed container until it is used in the preparation of the inhibitor formulation. The 2-oleynic-2'-naphthenic bisimidazoline obtained with the indicated general procedure must be stored in a sealed container to protect its functionality.

The composition is prepared in the range between 0.5 and 3% by weight in xylene, depending on what is reported from the crude in the refinery, regarding the activity in corrosion. At 1% by weight, good results are obtained with crude oil of the heavy specific gravity type lower than 32"API and a content of recovered distillates @ 538 ° C lower than 80% by volume Additionally, 5% by weight of isopropanol is used for prepare the composition that will be applied in the internal parts of the equipment used in diesel and gasoline to protect it from corrosion.

Bisimidazoline 2-oleic-2'-naphthenic 1.0% Isopropanol 5.0% Xylene complete The percentages are by weight of each of the components.

With respect to the industrial application of inhibitory composition of the present invention, the following considerations are taken: Corrosion is the reaction of the metal with oxygen, hydrogen, acids, salts, which gives rise to the formation of corrosion mechanisms. The problem occurs with greater severity in three specific locations in a primary distillation plant in diesel and gasoline streams: 1. - Where water exists as in dew or condensation points. 2. - Where there is a change of direction that affects the speed, erosion and corrosion factor. 3. - Where there are dirt deposits. 4. - Formation of emulsions and / or suspensions in water-hydrocarbon.

On the other hand, it is known that high concentrations of chloride ions give rise to the following diagnosis: 1. - Increase water conductivity. 2. - Increase the solubility of the iron sulfide film at pH less than 5. 3. - Decrease in the initial pH of the condensate associated with the hydrogen ion. 4. - Causes corrosion points in the places where chloride salts are deposited.

All these problems make it necessary to use additives that act as efficient corrosion inhibitors and also as neutralizers when the nitrogens of the imidazoline ring have the capacity to accept protons from an acidic medium, antifouling agents and demulsifiers by having improved rheological properties that prevent the formation of emulsions or suspensions in the water-hydrocarbon interface. For a good application of these chemicals, certain parameters must be taken into account and in this case the parameters that were analyzed for the injection of the inhibitory composition from the 2-oleic-2'-naphthenic bisimidazoline of the present invention were: • The type of heavy crude with specific gravity lower than 32 ° API and a recovered distillate content @ 538 ° C lower than 80% by volume.

• The type of distillation column: atmospheric, vacuum or pressurized.

• The pH of the bitter waters from each of the condenser banks of the trimmer, fractionator and vacuum columns of the plant (5.5 to 7.5).

• The temperature of the dome (130-160 ° C).

• Injection point of the inhibitor.

For the inhibiting composition of the present invention, it was found to work well in laboratory tests at up to pH = 4 and does not form emulsions or suspensions in the water-diesel or water-gasoline.

Tests of inhibition of corrosion and demulsifying activity.

To quantify the ability to inhibit corrosion of the inhibitory composition of the present invention, NACE evaluation methods TM0172, AST-D-1094 and NACE ID182 are applied.

The NACE TM0172 method evaluates the corrosive properties of distillate fuels and in preparation for transport through pipelines. It uses a steel cylinder that is subjected to a mixture of corrosive hydrocarbon and water. Concentrations are tested from 10 ppm to higher to determine the minimum concentration of maximum efficiency. This test is also called a rust test.

The AST-D-1094 test quantifies the efficiency in the protection against corrosion and allows confirming the results obtained with the NACE TM0172 test. Additionally, the NACE ID182 test methodology allows to determine the demulsifying capacity.

Table 1 shows the results of these tests for the inhibitory composition of the present invention that was prepared with the 2-oleic-2'-naphthenic bisimidazoline as an active ingredient in the composition of the present invention.

Table 1. Comparison of the results obtained with the corrosion inhibiting composition of the present invention and two commercial corrosion inhibiting compositions.

Principle Active tolerance of No.%% to water 10ppm Rust composition Test inhibitor efficiency 10 ppm 10 ppm Corrosion interface Separation Imidazoline- 1 40 65 1 3 imidazole cyclohexylamine 2 50 63 1 3 Bisimidazoline 2-oléica-2'- 3 0 92.6 2 2 naphthenic

Claims

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

1. A corrosion inhibiting composition based on the 2-oleic-2'-naphthenic bisimidazoline characterized in that it comprises the following weight percentage composition: 1.0% bisimidazoline 2-oleic-2'-naphthenic, 5% isopropanol, and the amount necessary to complete 100 g of solution with xylene.

2. A corrosion inhibiting composition based on bisimidazoline 2-oleic-2-naphthenic, according to clause 1, characterized in that structure 1 of the active principle is: where the imidazoline rings are linked by an ethyl bridge, in one of the imidazoline rings there is in C2 an oleoyl hydrocarbon chain having 18 carbons with a double bond between carbons 9 and 10 and in the other imidazoline ring it has in C2 'a cyclohexyl.

3. A corrosion inhibiting composition according to clauses 1 and 2, which when dosed between 5 and 18 ppm in the output of the dome of a primary distillation plant with gasoline and diesel streams, is characterized by an efficiency of 90 98% as a corrosion inhibitor, and a 0% rust value according to the method according to the ASTM-D-1094 test.

4. A corrosion inhibiting composition that when dosed between 5 and 18 ppm at the water-hydrocarbon interface at the outlet of the dome of a primary distillation plant with gasoline, turbosine or diesel streams, in accordance with clauses 1 to 3, characterized because it minimizes the rust to a value of 0 according to the NACE method TM0172.

5. A corrosion inhibiting composition that when dosed between 5 and 18 ppm, in accordance with clauses 1 to 4, is characterized by having a water tolerance of 2 according to the test methodology NACE ID182.

6. A corrosion inhibiting composition, in accordance with clauses 1 to 5, characterized in that it is added to 15 diameters after the exit of the dome from the atmospheric tower

7. A corrosion inhibiting composition, according to clauses 1 to 6, characterized in that it resists acidic media up to a pH = 4.

8. A corrosion inhibiting composition, in accordance with clauses 1 to 7, characterized in that it does not form emulsions or suspensions at the water-diesel or water-gasoline interface.