The problem of recycling waste fan gear oil

April 17, 2024

The problem of recycling waste fan Gear Oil

Wind turbine gear oil is a synthetic gear oil, because of its special performance characteristics is widely used in the fan growth gear box, the main role is to lubricate the fan gear box gear and bearings, prevent gear and bearings wear, rust, but also play an auxiliary system heat dissipation role. If the speed increase gearbox is compared to the "heart" of the fan, then the gear oil is the "blood" of the fan, it can be seen that the gear oil is an important part of the wind turbine.

Gear oil in the long-term operation process is usually polluted and aging to make it deteriorate, deterioration will have a serious adverse impact on the physical and chemical properties of gear oil, will also accelerate the occurrence of mechanical and chemical wear, shorten the service life of the fan gearbox, serious will increase the risk of gearbox overhaul. Therefore, the fan gear oil has a safe service life, beyond this life, it is necessary to replace the gear oil, otherwise it will bring safety risks.

Second, waste wind turbine gear oil treatment

The service life of the fan gear oil is generally 5-6 years, because the fan is mostly in the extremely hot, extremely cold, dust or near the coast, the harsh natural environment will affect the service life of the fan gear oil, so the monitoring data of the gear oil is an important basis for determining its life.

To achieve the service life, the index detection has not met the requirements of the fan gear oil, that is, the waste fan gear oil, due to the excessive performance and can not play the purpose of protecting the gearbox, this situation requires the waste oil replacement treatment, and the replacement of the waste fan gear oil many are incinerated. The main indexes of new and waste gear oil are compared in Table 1.

Table 1. Comparison of main indexes of new oil and waste oil

In recent years, with the development of wind power industry and the increase in the number of fans, the demand for fan gear oil is also rising. In order to extend the service life of waste fan gear oil and reduce fan maintenance costs, two different fan gear oil treatment methods began to appear in the industry, respectively, "purification" treatment and "regeneration" treatment.

(1) "purification" treatment

Definition of "purification" : the removal of impurities to make an object pure.

"Purification" treatment is a physical treatment process, which can be basically achieved through simple filtration. However, filtration treatment can only reduce the number of particle impurities, the viscosity of the waste oil, acid value, anti-wear elements and other key performance parameters have not changed, the waste oil is still waste oil, and still can not protect the gear box from wear.

It is undeniable that the removal of wear particles is necessary, because wear products will accelerate the aging of the oil and the wear of the metal parts, but only considering the filtration of wear particles is far from enough, and it is more necessary to consider the consumption of additives in the lubricating oil. The study on the loss of organic and inorganic additives in oil products shows that the loss of additives is related to the formation of complexes with aluminum, manganese, nickel and other metals, especially in the initial stage of lubricating oil work. In the later period of the service life of lubricating oil, the products of aging oil and iron, copper, molybdenum and other metals will produce acid-based complexes, which is also a direct influence factor on metal corrosion.

Therefore, the "purification" treatment can not solve the problem of Oil Additive consumption and oil aging products, and it can not fundamentally solve the problem of extending the service life of waste fan gear oil.

(2) "regeneration" treatment

The definition of "regeneration" : the processing of a certain waste product to restore the original performance and become a new product.

"Regenerative" treatment is a chemical treatment process. Chemical treatment requires a site to set up complex equipment and processes, but also requires sufficient chemical reaction temperature and time, these conditions can not be achieved online site. So, can the synthetic fan gear oil be "recycled" in the factory? Not like that!

(3) Waste fan gear oil recycling problems

3.1 Process Problems

The "regeneration" process of waste synthetic oil is complicated and can not achieve effective regeneration. The "regeneration" treatment of waste oil does have a certain market and historical application, and there are also some national laws and regulations and standards, but these are limited to the "regeneration" treatment application of ordinary mineral oil. For example, the National Ministry of Industry and Information Technology announced in 2015 "Waste mineral oil comprehensive utilization industry standard Conditions", the national standard GB/T 41961-2022 "Waste mineral oil lubricating oil treatment and disposal methods", and the group standard T/HEBQIA 141-2023 "Technical Specifications for Waste Mineral Oil recycling" clearly stipulates the process flow and technical methods of waste mineral oil recycling treatment.

Lubricating oil is a mixture of Base Oil and additives. As early as the 1990s, the American Petroleum Institute (API) divided base oils into five categories, one, two and three are mineral oils, four are PAO (English: Poly A-Olefins Chinese: polyalpha-olefin), five are esters, and four and five are synthetic oils. Synthetic oil, as the name suggests, is the oil produced by synthetic technology, which has been completely different from the mineral oil extracted and refined from petroleum, coal, and oil shale. Mineral oil and synthetic oil are different varieties of products, which are clearly stipulated in national standards and are also reflected in documents issued by international authorities.

The chemical composition of PAO based fan gear oil is fundamentally different from that of traditional mineral oil type gear oil, in addition to the huge difference in key physical and chemical properties, the more prominent is the difference in oxygen content. The oxygen content of synthetic fan gear oil is generally higher than that of mineral oil type gear oil. The huge difference in oxygen content, on the one hand, is reflected in the biodegradation properties of the two waste oils, on the other hand, it is also reflected in the "regeneration" treatment, the traditional "regeneration" treatment process of waste mineral oil, For example, solvent extraction process, vacuum distillation and solvent extraction combined process (Vaxon process), thin film evaporation and hydrogenation combined process (CEP process), etc., are completely not applicable to the "regeneration" treatment of high-viscosity waste synthetic oil, and the comparison of major regeneration technologies is shown in Table 2. According to the search data, at present, there are no reports at home and abroad that any professional institutions have successfully realized the recycling and recycling treatment of waste fan gear oil, and there is no association group standard, industry standard or national standard on the promulgation of technical specifications for waste synthetic oil recycling.

Table 2. List of main regeneration technologies

3.2 Legal Issues

There is no legal support for the recovery and "recycling" of waste synthetic oil. At present, the recycling of waste lubricating oil has been restricted by laws and regulations, such as HW08 in the National Hazardous Waste List (2021 edition), which stipulates that "mineral oil and mineral oil-containing waste". However, these laws and regulations only cover mineral oil waste, and do not cover waste synthetic oil. Therefore, the use of the "Hazardous Waste Business License" for the recovery and recycling of the gear oil of the composite fan is a non-compliant violation.

It can be seen that the "regeneration" treatment of waste fan gear oil is only a smoke screen, and there is no real technical treatment means to achieve "regeneration", and it is impossible to extend the service life of gear oil.

Iii. Summary and Suggestions

For waste fan gear oil, as far as the current situation is concerned, whether it is "purification" treatment or "regeneration" treatment can not help the waste oil to extend its service life. However, with the development of science and technology, waste composite fan gear oil will be recycled in the future.

With the increase in the use of synthetic lubricants, it is necessary to further develop regenerative treatment methods. Therefore, it is suggested that the environmental protection department should further standardize the laws and regulations, so that the recycling and recycling behavior of waste synthetic oil can be followed by laws. At the same time, it is also suggested that petrochemical research institutions should break through the technical bottleneck of recycling waste fan gear oil as soon as possible, and realize the recycling of recycling in a real sense.

Author:

Mr. James

E-mail:

sales@cn-lubricantadditive.com

Phone/WhatsApp:

+86 13783582233