LU501024B1

LU501024B1 - Preparation method of nano particle modified insulating oil based on iron occurrence form

Info

Publication number: LU501024B1
Application number: LU501024A
Authority: LU
Inventors: Haidan Lin
Original assignee: Electric Power Res Institute Of Jilin Electric Power Co Ltd Jilin China
Priority date: 2021-12-16
Filing date: 2021-12-16
Publication date: 2022-06-16

Abstract

A method for preparing nano-particle modified insulating oil based on iron occurrence form. The preparation method includes: the ethanol solution of sodium oleate and the ethanol solution of hexamethylenetetramine with different mass fractions are respectively prepared, and then mixed uniformly with insulating oil, and hexadecene is added to continue the reaction under stirring and constant temperature water bath conditions. The method of the present invention effectively eliminates the influence of different occurrence forms of iron on the aging and electrical properties of insulating oil, and successfully solves the agglomeration, precipitation and other problems that occur in different occurrence forms; different forms of iron can form modified nanoparticles, which can significantly improve the insulating performance and thermal conductivity of insulating oil; the formed nanoparticles can capture oxygen molecules generated during the aging process of the insulating oil and adsorb metal ions, thereby delaying the aging of the insulating oil.

Description

DESCRIPTION 0501084 Preparation method of nano particle modified insulating oil based on iron occurrence form

TECHNICAL FIELD The invention belongs to a technology of preparing modified nano particles, more specifically relates to a method for preparing modified insulating oil nano particles in an oil-immersed power transformer.

BACKGROUND In the process of power transmission and transformation, transformers play a vital role in the safe operation of the whole power grid. Insulating oil is an important medium for insulating and cooling of transformers, and its operation stability mainly depends on the insulation performance and heat dissipation performance of insulating oil. In recent years, the content of metal ions in insulating oil has attracted much attention, and metal corrosion and deposits usually occur in some faulty transformers. Numerous studies have found that the increase of metal content in insulating oil seriously declines the insulation ability of transformers, thus leading to the decrease of the initial voltage and breakdown strength of partial discharge, and finally causing the overheating or discharge failure of transformers.

When the subway type transformer core is in abnormal operation state such as overheating or discharging, the polar substances inherent in insulating oil and free radicals generated at the initial stage of oxidation attack the surface of iron material, which accelerates the corrosion or melting loss of iron and dissolves iron in oil, thereby forming different occurrence forms of iron, such as ionic state, inorganic state and organic complex state; different occurrence forms of iron will establish a relatively stable dissolution equilibrium in oil products. For example, when there is a large amount of peroxide in oil, the peroxide will react with iron ions to form a stable organic complex state, and the acidic substances generated in the reaction process will accelerate the transformation of simple iron or inorganic iron into iron ions.

Iron ion as an active charged ion, can activate the surrounding hydrocarbon molecules to generate free groups under the condition of applied voltage, so as to make directional movement in the electric field, thus increasing the electrophoretic conductivity phenomenon;

more importantly, iron ions as catalyst, accelerate the decomposition of intermediate products LUS01024 produced in the oxidation process of oil products, thus accelerating the aging of insulating oil, leading to the degradation of chemical properties of insulating oil and seriously affecting the electrical properties of oil products. In view of the fact that the iron content in insulating oil has an important influence on the chemical properties, fluidity and electrical properties of oil products; therefore, how to efficiently and environmentally-friendly remove iron pollutants in insulating oil is of great significance to ensure the safe and stable operation of transformers.

However, at present, there are few researches and effective treatment measures for removing iron impurities in oil.

In the previous research, some scholars used white earth, activated alumina, chitosan, sepiolite and other adsorbents to remove iron impurities in insulating oil, and achieved good removal effect. However, in the process of removing iron impurities by the adsorbent mentioned above, many impurities will also be dissolved in the insulating oil, and the influence of impurities on the performance of oil needs further exploration. For example, when oil is treated with activated alumina, a large amount of aluminum ions are dissolved in the oil, resulting in aluminum pollution. At present, the research based on nano-modified electrolyte has attracted much attention, many scholars have made nano-adding treatment for traditional electrolyte materials. Compared with traditional electrolyte, nano-electrolyte shows excellent electrical performance. Therefore, adding nanoparticles into insulating oil to form nanofluid has become an important means to improve the dielectric strength and thermal conductivity of insulating oil.

Based on this, the invention proposes a method for preparing nano-particle modified insulating oil based on the occurrence form of iron. Combining the occurrence form of iron impurities in insulating oil and the chemical characteristics of insulating oil, the pollution of iron impurities is removed through the generation of modified nano-particles, and improving the performance of insulating oil at a lower cost.

SUMMARY The objective of the invention is to propose a method for preparing nano-particle modified insulating oil based on iron occurrence form, so as to improve the shortcomings of the prior art.

A method for preparing nano-particle modified insulating oil based on iron occurrence 17901026 forms comprises the following steps: (1) preparing 40 mL of sodium oleate ethanol solution with a mass fraction of 40-80%, stirring well and setting aside, preparing 10 mL of ethanol solution of hexamethylenetetramine with a mass fraction of 5-10%, stirring evenly and setting aside; (2) mixing the prepared ethanol solution of oleic acid and ethanol solution of hexamethylenetetramine, stirring them evenly, and standing for 2-4 hours; (3) 1 L of insulating oil and the solution obtained in step (2) are evenly mixed, 5-10 mL of hexadecene is added, and the mixture is stirred at 200 r/min and continuously reacted for 2 hours in a constant temperature water bath at 60-80°C.

The principle of the present invention is that the different occurrence forms of iron in the insulating oil are generally hydrophilic, and are prone to agglomeration, precipitation and other behaviors; according to the invention, iron ions can react to generate ferroferric oxide nanoparticles, and oleic acid as a surfactant can perform surface modification on nanoparticles with different occurrence forms, thus forming long-term stable lipophilic nanoparticles.

The advantages and beneficial effects of the present invention are: (1) Eliminating the influence of different occurrence forms of iron on the aging and electrical properties of insulating oil effectively, solving the agglomeration, precipitation and other problems successfully of different occurrence forms of iron, and avoid overheating or discharge failure.

(2) Different occurrence forms of iron can form modified nanoparticles, which significantly improves the insulation performance and thermal conductivity of insulating oil.

(3) The formed nanoparticles have a very high specific surface area, which can capture oxygen molecules generated during the aging process of the insulating oil, and can adsorb other metal ions, thereby delaying the aging of the insulating oil.

(4) The method of the invention has the advantages of low cost, simple operation, reliable operation, no secondary pollution and so on.

BRIEF DESCRIPTION OF THE FIGURES The figure shows the change rate of thermal conductivity and breakdown voltage of insulating oil before and after modification under different working conditions.

DESCRIPTION OF THE INVENTION LUS01024 According to the following specific embodiments, the method for preparing nano-particle modified insulating oil based on iron occurrence forms proposed by the invention will be further explained. It should be noted that the following embodiments are narrative rather than limiting, and the scope of protection required by the present invention is not limited by this embodiment. The raw materials used in the embodiments are all commercially available products.

A method for preparing nano-particle modified insulating oil based on iron occurrence forms is completed by the following steps: (1) preparing 40 mL of sodium oleate ethanol solution with a mass fraction of 40-80%, stirring well and setting aside, preparing 10 mL of ethanol solution of hexamethylenetetramine with a mass fraction of 5-10%, stirring evenly and setting aside; (2) mixing the prepared ethanol solution of oleic acid and ethanol solution of hexamethylenetetramine, stirring them evenly, and standing for 2-4 hours; (3) 1 L of insulating oil and the solution obtained in step (2) are evenly mixed, 5-10 mL of hexadecene is added, and the mixture is stirred at 200 r/min and continuously reacted for 2 hours in a constant temperature water bath at 60-80°C.

Embodiment 1 (1) preparing 40 mL of sodium oleate ethanol solution with a mass fraction of 40%, stirring well and setting aside, preparing 10 mL of ethanol solution of hexamethylenetetramine with a mass fraction of 5%, stirring evenly and setting aside; (2) mixing the prepared ethanol solution of oleic acid and ethanol solution of hexamethylenetetramine, stirring them evenly, and standing for 2 hours; (3) 1 L of 1%insulating oil and the solution obtained in step (2) are evenly mixed, 5 mL of hexadecene is added, and the mixture is stirred at 200 r/min and continuously reacted for 2 hours in a constant temperature water bath at 60-80°C.

It can be seen from the attached drawing (working condition 1) that this embodiment significantly improves the thermal conductivity and breakdown voltage of the insulating oil, and improves the electrical and thermal conductivity characteristics of the insulating oil.

Embodiment 2

(1) preparing 40 mL of sodium oleate ethanol solution with a mass fraction of 60%, 17901026 stirring well and setting aside, preparing 10 mL of ethanol solution of hexamethylenetetramine with a mass fraction of 7%, stirring evenly and setting aside; (2) mixing the prepared ethanol solution of oleic acid and ethanol solution of hexamethylenetetramine, stirring them evenly, and standing for 2 hours; (3) 1 L of 2% insulating oil and the solution obtained in step (2) are evenly mixed, 7 mL of hexadecene is added, and the mixture is stirred at 200 r/min and continuously reacted for 2 hours in a constant temperature water bath at 60-80°C.

It can be seen from the attached drawing (working condition 2) that this embodiment significantly improves the thermal conductivity and breakdown voltage of the insulating oil, and improves the electrical and thermal conductivity characteristics of the insulating oil.

Embodiment 3 (1) preparing 40 mL of sodium oleate ethanol solution with a mass fraction of 80%, stirring well and setting aside, preparing 10 mL of ethanol solution of hexamethylenetetramine with a mass fraction of 10%, stirring evenly and setting aside; (2) mixing the prepared ethanol solution of oleic acid and ethanol solution of hexamethylenetetramine, stirring them evenly, and standing for 2 hours; (3) 1 L of 3* insulating oil and the solution obtained in step (2) are evenly mixed, 10 mL of hexadecene is added, and the mixture 1s stirred at 200 r/min and continuously reacted for 2 hours in a constant temperature water bath at 60-80°C.

It can be seen from the attached drawing (working condition 3) that this embodiment significantly improves the thermal conductivity and breakdown voltage of the insulating oil, and improves the electrical and thermal conductivity characteristics of the insulating oil.

Claims

CLAIMS LU501024

1. A method for preparing nano-particle modified insulating oil based on iron occurrence forms, characterized in that the preparation of nano-particle modified insulating oil is completed by the following steps: (1) preparing 40 mL of sodium oleate ethanol solution with a mass fraction of 40-80%, stirring well and setting aside, preparing 10 mL of ethanol solution of hexamethylenetetramine with a mass fraction of 5-10%, stirring evenly and setting aside; (2) mixing the prepared ethanol solution of oleic acid and ethanol solution of hexamethylenetetramine, stirring them evenly, and standing for 2-4 hours; (3) 1 L of insulating oil and the solution obtained in step (2) are evenly mixed, 5-10 mL of hexadecene is added, and the mixture is stirred at 200 r/min and continuously reacted for 2 hours in a constant temperature water bath at 60-80°C.

2. The method for preparing nano-particle modified insulating oil based on iron occurrence forms according to claim 1, characterized in that the insulating oil is applied to an oil-immersed power transformer.