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11CHEMICAL SCIENCES
DEVELOPMENT OF NEW INHIBITORS AND RESEARCH OF THEIR PROPERTIES
Kamilov T.
Master's student of the Tashkent Chemical-Technological Institute
Kholikova S.
Candidate of Technical Sciences, Tashkent Chemical-Technological Institute
Ziyadullayeva K.
Chiqchik State Pedagogical institute of Tashkent region DOI: 10.5281/zenodo.6579812
ABSTRACT
Convenient methods have been developed for the synthesis of corrosion inhibitors based on available local raw materials in the process of condensation of Croton aldehyde with ammonia under normal conditions. The optimal conditions for the process have been established.
Keywords: corrosion inhibitor, oil production, croton fraction, ammonia, condensation.
Introduction: Corrosion control of gas production and transport equipment is carried out by various methods: by applying anti-corrosion insulation, by means of electrochemical protection, by using special grades of steels, inhibitors, etc. The demand of the Republic for corrosion and scale inhibitors is more than 5 thousand tons per year. Due to the lack of production of corrosion and scale inhibitors, the latter are imported from other countries for foreign currency.
The chemical industry is well developed in Uzbekistan. Ammonia, formaldehyde, acetaldehyde, urea, triourea, they can serve as potential raw materials for the production of corrosion and scale inhibitors, are large-tonnage products of the chemical industry of the Republic. In this regard, the development of convenient one-stage methods for the synthesis of corrosion and scale inhibitors based on local raw materials is highly relevant.
There are many known methods of combating corrosion. Of these, four main groups can be distinguished. The first group of protection is used at the stage of metal production in the process of its metallurgical and mechanical processing. The general theory of alloying is based on three main factors that characterize the effectiveness of the corrosive element.
The corrosion rate can be reduced or prevented altogether by creating alloys that form a layer of corrosion products with high protective properties on their surface under the action of an aggressive environment. Alloying structural steels with copper-zinc and aluminum increases the protective properties of the surface layer and eliminates the possibility of the appearance of internal stresses in it [1].
Experimental technique: The second fundamentally different way to increase the corrosion resistance of a metal is the electrochemical method. In the process of dissolution of a metal on its surface, two electrode reactions occur simultaneously: anodic -dissolution of the metal and cathodic - reduction of the oxidizer. With significant contact of the metal with an aggressive medium, the corrosion process stabilizes and a stationary state occurs, characterized by the equality of the rates of the anodic and cathodic reactions (ja=jk) and the corresponding values of the potential Ecor, called the stationary potential. It follows
from the stationarity condition that, to slow down the rate of dissolution of the metal, it is sufficient to reduce the rate of at least one of the electrode reactions [2].
Results and discussion: Programs of target projects for the modernization and technical renewal of the basic sectors of our economy make it possible to introduce modern innovative technologies designed to give a powerful impetus to Uzbekistan's entry into new frontiers, ensuring the competitiveness of our country in the world market. The accelerated development of the oil and gas industry has an impact on scientific and technological progress in the field of engineering and technology of drilling, production, transportation and processing of oil and gas. The growth in the number of new gas, gas condensate and oil fields involved in the development, the commissioning of gas pipelines and compressor stations requires the use of cost-ef ective methods and technical means to prevent the phenomena of corrosive ef ects on downhole, field, transport equipment and pipelines. About 60 billion cubic meters of natural gas, about 8 million tons of oil and gas condensate are produced annually in Uzbekistan. Natural gas, gas condensate and oil contain highly corrosive components such as hydrogen sulfide (1-5% vol.) And carbon dioxide (0.5-6.0 %).
In world practice, cathodic protection is widespread in protection against marine or underground corrosion, where most of the metal structures, pipelines, etc. are subject to protection in one form or another. Magnesium alloys are used as soluble anodes and protectors to protect ferrous metals, less zinc and aluminum alloys. Cathodic protection with the use of anodes - protectors has its own inconveniences, since it requires rather frequent replacement of consumable protectors, which can sometimes become economically unprofitable.
Anodic protection is used to protect sections of chemical plants, which are made of metal that can be passivated in this environment. The method of anodic protection is promising, but requires the development of control over the mode of maintaining the required potential [4].
The third most versatile method of protecting
metals from corrosion is the application of both metallic and non-metallic coatings to the metal surface.
The main purpose of the protective coating is, on the one hand, to create a barrier layer that prevents the penetration of a corrosive medium to the metal surface, and on the other hand, to restrict or completely prevent the formation of a new phase of corrosion products at the metal-coating interface. The material of the protective coating, first of all, must have high chemical resistance, low permeability to water, gases, chlorine vapor, sulfate, etc., mechanical strength and structural stability [1].
Among protective metal coatings, zinc coatings account for the largest specific weight. Their main area of application is the protection of ferrous metal products from atmospheric corrosion. Zinc protects ferrous metals from corrosion not only mechanically as a coating, but also electromechanically acting as an anode. According to the materials used and the method of production, non-metallic coatings are subdivided into lining, rubber coating, paint and varnish and others [2]. Modern paints and varnishes are complex mixtures containing, in addition to a film-forming agent and a pigment, fillers such as surfactants, dispersants, thickeners, solvents and other additives. Paints and varnishes have a number of advantages over other types of protective coatings. The main disadvantages of paint and varnish coatings include their limited steam, gas and water permeability, as well as insuffi-
cient heat resistance [5]. The fourth group of methods of combating corrosion is the treatment of a corrosive environment by introducing corrosion inhibitors. The introduction of small amounts (no more than 1 %) of an inhibitor into a corrosive environment can lead to a significant decrease in the corrosion rate of metals. In this case, the corrosion inhibition coefficient, equal to the ratio of corrosion rates in the absence and in the presence of an inhibitor, reaches values of 1000 or more.
Currently known inhibitors can protect almost any metal in a wide variety of environments: air, aggressive gases, sea and fresh water, coolants, water mixtures, acids and alkalis.
The main advantages of using inhibitors, in addition to the simplicity of the technology, is the ability to use conventional carbon steels instead of expensive stainless steels, and in some cases the possibility of improving the mechanical properties of the metal. The use of inhibitors is justified for technological processes with circulation of limited volumes of corrosive liquids and under the condition of low losses, which determines the actual consumption of the inhibitor.
Numerous organic and inorganic compounds with at least one element with unpaired electrons in their molecule can serve as corrosion inhibitors. In the production of oil and gas treatment, dozens of names of large-tonnage chemical reagents are used.
Table 1
Until now, Uzbekneftegaz JSC uses the following chemicals:
№ Name Brand Quantity ton
1. Water-soluble demulsifier Dissolvan - 4411 100,0
2. Oil-soluble demulsifier Dissolvan - 3359, Brand K-1 160,0
3. Gas Production Corrosion Inhibitor Dodikor V - 4543 350,0
4. Corrosion inhibitor for oil production Dodikor V -4712 1150,0
5. Scale inhibitor (concentrate) Dodiscale V- 2570 K 400,0
6. Antifoam (antifoam) DanoxAF-200 100
7. Fluorine containing foaming agent Finiflan- A3 F/A 270
8. Hydrocarbon foaming agent Analogue- nO-6 10000
Total 3530
Out of 8 positions, not a single chemical is produced in the Republic. In the Republic, JSC "Navoia-zot" produces methanol - 35 thousand tons per year: formaldehyde - 7 thousand tons per year; acetaldehyde - 200 thousand tons per year; acetic acid - 20 thousand tons per year, ammonia - more than 500 thousand tons/year. In the production of acetaldehyde, the so-called croton fraction is formed as a byproduct. In the amount of 800-3500 tons per year. Which is not processed but burned. The croton fraction has a trace. Composition % mass (average) Crotonic aldehyde - 57,4-66,95
Paraldehyde -13,45-29,47 Acetone - 0,63-10,56 Water - rest
In the literature [6] there are data on the use of crotonaldehyde as an inhibitor of hydrogen sulfide corrosion. However, due to the high toxicity of crotonaldehyde (its MPC in the working area is 0.5 ng / m3), this inhibitor has not found industrial application. With the aim of using crotonic aldehyde, creating a waste-free technology and protecting the environment, we studied the condensation reaction of crotonalde-hyde with ammonia monoethanolamine.
The process of condensation of crotonaldehyde form an unsaturated amino alcohol according to the with ammonia under normal conditions has been stud- scheme: ied. In this case, crotonaldehyde adds ammonia to
CHrCH=CH-CHO+NH;—> CH3-CH=CH-CH-NH2
!
OH
The reaction proceeds with the release of heat. The heat of formation of aminocrotonol was calculated [7], which is 41.97 kcal / mol.
When the condensation product of crotonalde-CHj CH=CH-CM NH2 —
I OH
We proved the occurrence of both reactions by taking the IR spectrum. In the IR spectra (tablets with KBr) of the resins, intense absorption bands were found - NH2 groups (1600-1500 cm-1), OH groups (3400-3200 cm-1), NH groups (3100-3500 cm-1 , CH -groups (3000-2700 cm-1), -C = C- (1680-1600 cm-1; 3100-300 cm-1. The presence of intense absorption bands in the IR spectra in the region of 750-650 cm-1 and 970-960 cm-1, characteristic for the -CH- group,
The resulting mixture of oligomers, mixture of products (IV and V) was tested as a corrosion inhibitor in a hydrochloric acid environment. The influence of the inhibitor concentration on the corrosion rate of steel grade C-3 in 15% hydrochloric acid was studied. (t =600C; t = 42).
Conclusion: Among the known methods of combating corrosion, inhibition is the most widely used, one of the simplest and most cost effective methods. The great advantage of this method is the possibility of its application without changing the existing technological processes for collecting and transporting gas. At present, the weight of gas condensate wells, in the production of which corrosive components are found - carbon dioxide and hydrogen sulfide, highly mineralized formation waters are subject to inhibition in order to protect from corrosive destruction of tubing and flow pipes, gas treatment units. Oil production processes are often accompanied by the deposition of solid sediments of inorganic substances that accumulate on the walls of wells and risers, in pumping equipment and ground communications of the oil collection and treatment system. The accumulation of salts complicates oil production, leads to damage to expensive equipment, time-consuming repair work, and, as a result, to a significant shortage and
hyde with ammonia is heated to a temperature of 200-1200C, it loses water and forms an unsaturated imine according to the following scheme:
—> CH . - CI l=CH - CI l=NH II
the formation of products IV and V.
Experiments have shown that the formation of products IV and V proceeds more easily than product III. If the final formation of compound III requires 4 days, then to obtain products IV and V, only 2-32 are required. It seems to us that this is due to the fact that compound II contains conjugated double bonds, which are easily broken, as in the case of 1,3-dienes.
Table 2
loss of oil.
References
1. Rachev H., Stepanov S. Corrosion Handbook. Per. with bulg. Ed. Isaeva N.I. -M; Mir, 1992, - 520 p.
2. Corrosion resistance of chemical production equipment. Methods for protecting equipment from corrosion. Ref. ed. Ed. Strokhana B.V., Sukhotina A.M. - L.; Chemistry, 1997, - 280 p.
3. Navruzov Kh., Sarankina SA et al. Alkylation of phenol in the presence of KU-2 cation. Uzbek. chem. magazine., 1999, No. 5, - p. 53-55.
4. Kezek V. M., Kukurs O. K. Purin B. A. Protection of metals from corrosion. - Riga; Avets, 2001, - 174 p.
5. Technology of varnishes and paints. O. V. Or-lova, T. N. Fomicheva, A. Z. Okupchikov, T. R. Kur-skiy. - M; Chemistry, 2000, -392 p.
6. Kurbanov F.K., Abdullaev T. et al. The use of crotonic aldehyde to protect steel from hydrogen sulfide corrosion. Express information. Ser. Corrosion and environmental protection, 2005, issue 9, p. 7-11.
7. Stall D., Westrum E., Zinke G. Chemical thermodynamics of organic compounds, Moscow: Mir, 2001, 807 p.
№ Inhibitor concentration, % Corrosion rate g/m2 hour Degree of protection %
1. No additive 13 -
2. 0,2 6,5 95,0
3. 0,4 4,7 96,4
4. 0,6 4,1 96,8
5. 0,8 2,0 99,0
6. 1,0 1,4 99,0
7. 1,2 2,4 97,6
