Use of recycled base oil

Abstract

The present invention provides the use of reclaimed base oil in an industrial lubricating fluid comprising at least one base oil and at least one additive to improve one or more of the oxidative stability and low temperature performance of the industrial lubricating fluid.

Description

[Technical Field]

[0001] The present invention relates to the use of recycled base oils in industrial lubricant formulations. [Background technology]

[0002] Lubricating fluids are required in all industrial equipment with moving parts. Thus, industrial lubricating fluids include hydraulic oils, gear oils, compressor oils, circulating oils, turbine oils, etc. Such industrial lubricating fluids generally contain one or more base oils and one or more additives. Typically, the additive treat rate of industrial lubricating fluids is much lower than that of engine oils, with additive treat rates of less than 5 wt.% being common.

[0003] At such low additive treat rates, the base oil used is of key importance. Typically, so-called "virgin" base oils are used in the manufacture of industrial lubricating fluids. These are typically produced directly from crude oil or natural gas via refining or synthetic processes.

[0004] Disposal of used lubricating fluids requires careful processing, and waste streams are often used as burner fuel. In all technology sectors, it is necessary to consider the carbon footprint of products and try and ensure that raw materials are reused and recycled where possible. This has led to the development of so-called "refined base oils." Refined base oils (RRBOs) are base oils obtained from reprocessing used lubricating oils to remove contaminants, oxidation products, and additives.

[0005] Techniques such as distillation, thermal deasphalting, or solvent (often propane) deasphalting are used to recycle used lubricating fluids. The intermediate products produced by recycling techniques are unfinished and typically unsuitable for use as lubricants without further improvement. Finishing techniques such as clay treatment, hydrotreating (see, for example, EP 3921390 A1 and U.S. Pat. No. 11034895 B1), or solvent extraction (as described in CN 107574012 A) can then be used to "finish" the intermediate to a marketable base oil. The combination of recycling and finishing techniques is commonly referred to as reclaiming. Additional pretreatment steps can also be used to remove sludge, water, and added metals before recycling.

[0006] Previously, recycled base oils were considered to be of inferior quality to unrefined base oils. With the development of improved recycling technologies, this is no longer the case. However, recycling technologies and the recycled base oils thus produced have focused on producing and using base oils of sufficient quality that can meet the standards set for lubricating oils throughout the industry (see, for example, Chinese Patent Application Publication Nos. 104673460(A) and 104673461(A)). The inventors' intention is to use RRBOs to develop improved lubricating oils. Summary of the Invention

[0007] Accordingly, the present invention provides the use of reclaimed base oil in an industrial lubricating fluid comprising at least one base oil and at least one additive to improve one or more of the oxidative stability and low temperature performance of the industrial lubricating fluid. DETAILED DESCRIPTION OF THE INVENTION

[0008] One or more specific embodiments of the present disclosure are described below. The described embodiments are examples of the techniques of the present disclosure. Moreover, in order to provide a concise description of these embodiments, all features of an actual implementation may not be described in this specification.

[0009] When introducing elements of various embodiments of the present disclosure, the articles "a," "an," and "the" are intended to mean that there are one or more of the elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements. In addition, it should be understood that references to "one embodiment" or "an embodiment" of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

[0010] The present inventors have surprisingly found that reclaimed base oils can be used to provide improved fluids for use as industrial lubricating fluids.

[0011] Industrial lubricating fluids include, but are not limited to, those used as hydraulic oils, gear oils, compressor oils, circulating oils, and turbine oils. Industrial lubricating fluids according to the present invention comprise at least one base oil and at least one additive.

[0012] The industrial lubricating fluid preferably comprises at least 95 wt. % of the base oil. According to the present invention, at least a portion and up to 100 wt. % of this base oil is recycled base oil. Preferably, at least 10 wt. % of the base oil in the industrial lubricating fluid is recycled base oil. Depending on the viscosity grade of the industrial lubricating fluid, the RRBO treat rate can be as high as nearly 100% for light grade industrial lubricating fluids, while heavy grade industrial lubricating fluids may require heavy unrefined base oil to fill the viscosity gap.

[0013] The base oil in the industrial lubricating fluid that is not recycled base oil may be any suitable base oil typically used in lubricating fluids, including base oils belonging to Groups I to IV of the API (American Petroleum Institute - see Table 1) base oil categories, which may be used alone or in mixtures.

[0014] [Table 1]

[0015] The reclaimed base oil used in the present invention is preferably Group I or Group II according to the API base oil category. More preferably, the reclaimed base oil used in the present invention is Group I according to the API base oil category. A typical reclaimed Group I base oil falls within the API category of Group I base oil, but has characteristics that are not typical of unrefined Group I base oils. Preferably, the saturates content of the reclaimed Group I base oil is at least 80%, more preferably at least 90%. The viscosity index of the reclaimed Group I base oil is preferably at least 95, more preferably at least 105. The sulfur content of the reclaimed Group I base oil is preferably 0.3% or less, more preferably 0.1% or less. The sulfur content of the reclaimed Group I base oil is greater than 0.03%, consistent with the API classification.

[0016] The reclaimed base oil used in the present invention is preferably a base oil recycled from used lubricating fluids using solvent extraction or hydroprocessing.

[0017] Preferably, the total amount of additives in the industrial lubricating fluid is less than 5 wt. %, more preferably less than 3 wt. %, and even more preferably less than 2 wt. %, based on the total weight of the industrial lubricating fluid. Suitably, the total amount of additives in the industrial lubricating fluid is at least 0.1 wt. %, based on the total weight of the industrial lubricating fluid. Additives may be incorporated into the industrial lubricating fluid alone or as part of one or more additive packages. Whether added alone or in an additive package, diluent oil may be included with the additives and form part of the finished industrial lubricating fluid.

[0018] Depending on the end use of the industrial lubricating fluid, different types of additives are suitable, including, but not limited to, anti-wear additives, extreme pressure additives, friction modifiers, viscosity index improvers, pour point depressants, antioxidants, rust and corrosion inhibitors, dispersants, demulsifiers and anti-foam agents.

[0019] Examples of the anti-wear additives and extreme pressure additives include phosphorus compounds such as phosphate esters, acidic phosphate esters, amine salts of acidic phosphate esters, basic phosphate esters, phosphites, phosphorothioates, zinc dithiophosphates, esters of dithiophosphoric acids with alkanols or polyether alcohols, and derivatives thereof, phosphorus-containing carboxylic acids, and phosphorus-containing carboxylic acid esters.

[0020] Examples of viscosity index improvers include non-dispersant viscosity index improvers such as polymethacrylates and olefin polymers such as ethylene-propylene copolymers, styrene-diene copolymers, polyisobutylene, and polystyrene, as well as dispersant viscosity index improvers obtained by copolymerizing these with nitrogen-containing monomers, which may be made of a type other than the copolymer of an olefin and an alkyl methacrylate.

[0021] As examples of pour point depressants, mention may be made of polymethacrylate polymers.

[0022] Suitable antioxidants include amine-based antioxidants, sulfur-based antioxidants, phenol-based antioxidants, and phosphorus-based antioxidants, which may be used alone or in combination.

[0023] Examples of demulsifiers suitable for use in the industrial lubricating fluid according to the present invention include demulsifiers known in the art that are commonly used as additives for lubricating oils. Antifoaming agents may also be added to impart antifoaming properties to the lubricating oil composition of the present invention.

[0024] As examples of antifoaming agents suitable for use in the industrial lubricating fluids according to the invention, mention may be made of organosilicates such as dimethylpolysiloxane, diethylsilicate and fluorosilicones, as well as non-silicone type antifoaming agents such as polyalkylacrylates.

[0025] The invention will now be illustrated by the following non-limiting examples. [Example]

[0026] Various industrial lubricant formulations were blended and tested as shown in Tables 3 to 6. The following base oils (having the properties listed in Table 2) were used in the examples.

[0027] Group I 150SN and 500SN are commercially available from Hindustan Petroleum Corporation Limited (HPCL) under the trade names Alprol N32 and Alprol N100.

[0028] Group II 150N and 500N are commercially available from Hainan Handi Sunshine Petrochemical Co. under the tradenames HDS-150N and HDS-500N.

[0029] Group I RRBO 150SN is commercially available from Hebei Jingu Recycling Resources Development Co. under the trade name JINGU 150SN.

[0030] Group II RRBO 150N is commercially available from Changzhou FINAS Energy Technology Co. under the trade name FINAS 150N.

[0031] [Table 2]

[0032] The hydraulic fluid package used in the formulation is a standard commercial hydraulic fluid additive package.

[0033] The pour point depressants used in the formulation are standard commercially available pour point depressants.

[0034] The anti-foam additives used in the formulations are commercially available anti-foam additives.

[0035] It can be seen from Tables 3-6 that the Group I or Group II RRBO based samples exhibit performance advantages over their crude base oil counterparts, such as higher VI, lower viscosity at 0°C, and better oxidation stability, as reflected by the RPVOT and TOST test results.

[0036] [Table 3]

[0037] [Table 4]

[0038] [Table 5]

[0039] Table 6

Claims

1. 1. Use of recycled base oil in an industrial lubricating fluid comprising at least one base oil and at least one additive to improve one or more of the oxidation stability and low temperature performance of the industrial lubricating fluid.

2. 10. The use of claim 1, wherein the industrial lubricating fluid comprises at least 95% by weight of a base oil.

3. 3. The use according to claim 1 or 2, wherein at least a portion and up to 100 wt. % of the base oil is recycled base oil.

4. 4. Use according to any one of claims 1 to 3, wherein the recycled base oil is selected from one or both of Group I and Group II according to the API base oil categories.

5. 5. The use of claim 4, wherein the reclaimed base oil is a Group I base oil having a viscosity index of at least 95, a sulfur content of 0.3% or less, and a saturates content of at least 90%.

6. The use according to any one of claims 1 to 5, wherein the reclaimed base oil is a base oil recycled from used lubricating fluids using solvent extraction or hydroprocessing.

7. 7. Use according to any one of claims 1 to 6, wherein the total amount of additives in the industrial lubricating fluid is less than 5 wt. %, more preferably less than 3 wt. %, even more preferably less than 2 wt. %, based on the total weight of the industrial lubricating fluid.

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