HK1217510B - Process and apparatus for the preparation of a cylinder oil - Google Patents

Description

Method and apparatus for preparing cylinder oil

Technical Field

The present invention relates to a method for producing cylinder oil, comprising the following steps:

- Provide waste oil,

- Provide new cylinder oil, and

- Mix the used oil with new cylinder oil,

Among them, used oil has a lower TBN value than new cylinder oil.

The invention also relates to a method for operating an internal combustion engine, comprising the following steps:

- preparing a cylinder oil according to the method for producing a cylinder oil as described herein, and

- Using the cylinder oil in an internal combustion engine.

The present invention also relates to an apparatus for preparing cylinder oil, comprising a mixing device for mixing waste oil with new cylinder oil, wherein the mixing device is in fluid communication with:

- at least one internal combustion engine compartment containing waste oil, or at least one storage tank containing waste oil,

- at least one storage tank for new cylinder oil, and

- At least one cylinder of an internal combustion engine.

Another aspect of the present invention relates to the use of waste oil and new cylinder oil to prepare cylinder oil.

The method, apparatus and use of the invention are particularly suitable for use with a two-stroke crosshead engine installed on a ship and/or with a four-stroke auxiliary engine installed on a ship.

Background Art

Cylinder oil is a type of oil typically used to lubricate the cylinders in internal combustion engines. Cylinder oil has multiple functions. Its primary function is to provide lubrication between the cylinder and/or piston rings and cylinder liners. Therefore, its purpose is wear control. Another important function of cylinder oil is to prevent corrosion of the cylinder material and the liner or walls of the combustion chamber. The cylinder oil itself should be stable against thermal decomposition and have good oxidation resistance, good anti-foaming properties, and good water emulsification properties. Pressure performance is also important for cylinder oil.

Most of these properties of cylinder oils are controlled by additives. Kinematic viscosity is primarily controlled by the composition of the oil itself. Hydrocarbons with long carbon chains and hydrocarbons with branched carbon chains tend to have higher kinematic viscosities. Cylinder oils are primarily given corrosion protection by adding alkaline organic compounds (e.g., amines). Organic diimines, as described in GB 1,183,345 A, are primarily used as additives in cylinder oils to control corrosion protection. Alkaline additives neutralize acids (e.g., sulfuric acid and other acids) formed by sulfur or sulfur-containing compounds contained in the fuel during combustion in the combustion chamber. Cylinder oils may contain 0.1% to 30% by weight of these diimines. Another example of a suitable additive for enhancing wear and corrosion resistance is alkylamine-alkylphosphates, as disclosed in US 2004/144355 A.

For some lubrication applications (e.g., in lubricating cylinders in crosshead diesel engines using a total loss lubrication system and burning heavy fuel oils with widely varying sulfur contents), the engine lubrication requirements vary to such a large extent and with sufficient frequency that a single lubricant formulation cannot provide adequate performance over the entire operating range. This inability to respond leads to at least increased engine maintenance requirements and, more commonly, unnecessary expenses due to repair costs, downtime, and excessive oil consumption. Therefore, there is a need to be able to change the composition of the lubricant in response to the actual lubrication needs of the engine. US 2004/144355 A proposes a system in which additives are added to the primary lubricant to adapt the corrosion resistance to the fuel and engine conditions. The use of waste oil is not disclosed in the literature.

Cylinders typically experience greater wear than other engine parts, as engines have higher temperatures and the combustion process places even harsher conditions on the cylinder oil. Therefore, cylinder oil is often more contaminated than the oil in the rest of the engine (the so-called system oil). In engines where the system oil is integrated with or in contact with the cylinder oil, the cylinders introduce significant amounts of contaminants into the system oil. In large engines that can use tens of thousands of liters of system oil, the cylinder and system oils are typically kept separate to prevent contamination of the system oil. In such systems, cylinder oil cannot be regenerated by mixing with the system oil. Consequently, the quality of the cylinder oil rapidly deteriorates. To maintain adequate cylinder oil quality, the cylinder oil must be frequently exchanged or, through operation in a so-called "total loss" lubrication system, the cylinder oil is only used once. While total loss systems reduce the cost of the system oil, the cost of the cylinder oil remains high. EP 1 640 442 B1 proposes a system in which the engine's used system oil is mixed with additives to produce cylinder oil. This system uses waste oil to produce cylinder oil, thereby reducing costs and environmental concerns. While this system provides adequate control over the corrosive properties of the produced cylinder oil and allows for the utilization of surplus conventional cylinder oil, it also has disadvantages. The cylinder oil produced by this method has a significantly lower kinematic viscosity and, therefore, inferior lubricating properties compared to conventional cylinder oil. Consequently, a larger amount of this cylinder oil must be used to achieve the same lubricating properties, thus diminishing the effect of reducing oil consumption.

Furthermore, the additives used have a very high kinematic viscosity, typically approaching 100 ^mm² /s at temperatures greater than or equal to 100°C. This liquid can only be moved by pumps if it is insulated. Consequently, tanks, pipes, mixers and other equipment that come into contact with the additive need to be fitted with heaters. In cold climates, equipment such as tank trucks that deliver the additive to ships or other installations that come into contact with the additive also need to be fitted with heaters or well insulated. Logistics are therefore a major issue when using such additives on site to manufacture cylinder oils. In addition to logistics, there is always the risk of local overheating, which can easily occur and contribute to oxidation of the additive, which can significantly reduce the quality of the additive and therefore the quality of the cylinder oil produced.

Summary of the Invention

The present invention aims to provide a system for reducing the amount of lubricant used in internal combustion engines, in particular the amount of cylinder oil and/or system oil. Furthermore, the present invention aims to provide a method and apparatus for better controlling the kinematic viscosity when producing cylinder oil from waste oil. Another object of the present invention is to improve wear and corrosion resistance.

The present invention relates to a method for producing cylinder oil, comprising the following steps:

- Provide waste oil,

- Provide new cylinder oil, and

- Mix the used oil with new cylinder oil,

The waste oil has a TBN value lower than that of new cylinder oil.

This method allows waste oil to be reused as cylinder oil, reducing costs and environmental concerns. It also provides partially recovered cylinder oil with a higher kinematic viscosity than methods described in the prior art, i.e., the kinematic viscosity of the partially recovered cylinder oil is closer to that of typical cylinder oil. Mixing waste oil with cylinder oil has unexpectedly beneficial effects, particularly for mixing system oil with cylinder oil, as the typical purpose of cylinder oil is only achieved when system oil and cylinder oil are separated. Therefore, mixing these oils to produce cylinder oil had not been considered before the present invention.

According to the present invention, cylinder oil is an oil designed to lubricate the cylinders in internal combustion engines. The cylinder oil preferably contains alkaline (i.e., alkaline) additives. Preferably, the cylinder oil produced by the present invention is an oil designed to be used as an all-loss oil. It is also preferred that the cylinder oil is designed to be used in a crosshead diesel engine, in particular in a two-stroke crosshead diesel engine, in particular a diesel engine installed on a ship (e.g., a steamer). However, the engine may also be installed in a fixed system. Alternatively, it is preferred that the cylinder oil is designed to be used in a four-stroke diesel engine with or without a crosshead, in particular a diesel engine installed on a ship (e.g., a steamer). Such an engine may, for example, be an auxiliary engine on board a ship for generating energy in combination with a generator, etc.

Further preferably, the waste oil at least partially comprises used system oil from at least one crosshead diesel engine that utilizes a total-loss lubrication system for its cylinders. However, most preferably, the internal combustion engine is installed on a ship and the method is performed on board. Further preferably, the engine is a crosshead diesel engine that utilizes a total-loss lubrication system for its cylinders.

In the context of the present invention, the term "new cylinder oil" refers to cylinder oil that does not contain untreated waste oil. However, new cylinder oil may include recycled oil (i.e., recycled oil) that has been treated at a factory. These examples are typical commercially available cylinder oils. Preferably, the cylinder oil used in the present invention has a high TBN value and a high viscosity. Particularly useful is NAVIGO 100MCL ^™ (available from LUKOIL Marine Lubricants, Hamburg, Germany), which has a kinematic viscosity of 20 ^mm² /s at 100°C and a TBN value of 100, and is the only commercially available cylinder oil with a TBN value of 100 or greater.

In the context of the present invention, the term "waste oil" refers to or includes oil that has been used for any type of lubrication or other purpose. Waste oil may have been used as such, or it may contain oil that has already been used. It is particularly preferred to use waste oil that has been processed in some other way.

One factor to consider when evaluating the lubricating properties of cylinder oil is kinematic viscosity. If the kinematic viscosity of the cylinder oil is too low, the oil film on the cylinder liner may be discontinuous, and the cylinder or piston rings may come into direct contact with the cylinder liner, leading to increased wear. Another important factor in preventing corrosive wear is the alkalinity reserve in the oil film retained on the cylinder surface. As the piston moves downward, the cylinder surface is exposed to a corrosive environment that causes corrosive wear. The thickness of the oil film retained on the cylinder surface depends on the kinematic viscosity of the cylinder oil. The thinner the cylinder oil, the smaller the film thickness and alkalinity reserve of the oil film covering the cylinder surface, because less oil contains fewer alkaline compounds per surface area, leading to higher levels of corrosive wear. If the kinematic viscosity is too high, friction is excessive, resulting in a loss of engine performance, and the alkalinity reserve is excessive, which can form additional deposits on the upper piston area and the back of the piston rings, leading to higher levels of wear or scoring.

For the purposes of the present invention, all values of kinematic viscosity are measured in accordance with DIN 51562/2. Therefore, all values of kinematic viscosity stated herein are kinematic viscosities at 100° C. as stated in DIN 51562/2.

The cylinder oil of the present invention preferably has a kinematic viscosity of 14 mm ² /s or more at 100° C., more preferably 15 mm ² /s or more at 100° C., even more preferably 16 mm ² /s or more at 100° C., most preferably 17 mm ² /s or more at 100° C. The new cylinder oil of the present invention preferably has a kinematic viscosity of 16 mm ² /s or more at 100° C., preferably 18 mm ² /s or more at 100° C., most preferably 19 mm ² /s or more at 100° C. The kinematic viscosity of new cylinder oil is preferably in the range of 16 ^mm² /s to 24 ^mm² /s at 100°C, more preferably in the range of 18 ^mm² /s to 22 ^mm² /s at 100°C, and most preferably in the range of 19 ^mm² /s to 21 ^mm² /s at 100°C. The waste oil of the process of the present invention may have a kinematic viscosity of up to 25 ^mm² /s. The waste oil of the process of the present invention preferably has a kinematic viscosity in the range of 7 ^mm² /s to 15 ^mm² /s, more preferably in the range of 8 ^mm² /s to 13 ^mm² /s, even more preferably in the range of 9 ^mm² /s to 12.5 ^mm² /s, and most preferably in the range of 10 ^mm² /s to 12.5 ^mm² /s. Preferred is the process as described herein, wherein the waste oil has a lower kinematic viscosity than the cylinder oil.

One parameter used to determine the corrosion protection performance of cylinder oils is the TBN value (also known as the BN value or neutralization number). TBN stands for "Total Base Number," which defines the chemical equivalent of KOH, measured in milligrams, as the amount of acid necessary to neutralize the total base content of a 1-gram sample. For the purposes of this description, the TBN value is determined as described in ASTM D 2896.

The TBN value of the cylinder oil produced by any of the methods of the present invention is preferably suitable for the sulfur content of the fuel used in the internal combustion engine according to methods known in the art. For example, background art regarding this method is disclosed in US 2004/144355 A, which is incorporated herein by reference.

Cylinder oils produced by any of the methods described herein preferably have a TBN value greater than or equal to 10, preferably greater than or equal to 30, more preferably greater than or equal to 50, and most preferably greater than or equal to 60. The TBN value may also preferably be within one of the following ranges: 1 to 80, 1 to 30, 1 to 25, 1 to 10, 10 to 80, 10 to 60, 10 to 30, or 30 to 60. Waste oils typically have a TBN value less than or equal to 50, more typically less than or equal to 30, and often less than or equal to 15. Preferably, the new cylinder oils used in the present invention have a high TBN value and a high viscosity. Typically, the new cylinder oils used in the methods of the present invention as described herein have a TBN value greater than or equal to 10, preferably greater than or equal to 50, more preferably greater than or equal to 80, even more preferably greater than or equal to 90, and most preferably greater than or equal to 100. It may also be preferable to use new cylinder oil having a TBN value of less than or equal to 50, less than or equal to 40, or less than or equal to 25.

Mixing of the waste oil with the new cylinder oil may be accomplished by any means known to those skilled in the art to achieve mixing of the oils, however, mixing is preferably performed in a stationary mixing conduit, mixing tube, or in-line mixing unit. For example, a useful stationary mixer for use with the present invention is described in US Pat. No. 8,147,124. Alternatively, batch mixing can be performed in a separate oil tank equipped with an agitator.

Another preferred method as described herein is wherein the waste oil comprises one or more oils selected from the group consisting of: used hydraulic fluid, used gear oil, used system oil, used trunk piston engine oil, used turbine oil, used heavy-duty diesel oil, used compressor oil, and mixtures thereof. Preferably, the waste oil comprises used system oil. More preferably, the waste oil consists of used system oil.

Cylinder oils produced by any of the methods described herein typically include at least 2% waste oil, preferably at least 5% waste oil, and more preferably at least 10% waste oil. Even more preferably, cylinder oils produced by any of the methods described herein include at least 20% waste oil, and most preferably at least 30% waste oil. Cylinder oils produced by any of the methods described herein may include at least 40% waste oil, or at least 50% waste oil. Preferably, cylinder oils produced by any of the methods described herein include at most 60% waste oil, more preferably at most 50% waste oil, even more preferably at most 40% waste oil, and most preferably at most 30% waste oil. The amount of waste oil in cylinder oils produced by any of the methods described herein is preferably in the range of from 10% to 50%, more preferably in the range of from 20% to 40%.

Cylinder oil produced by any of the methods described herein typically comprises at least 1% new cylinder oil, preferably at least 5% new cylinder oil, and more preferably at least 10% new cylinder oil. Cylinder oil produced by any of the methods described herein may comprise up to 80% new cylinder oil or at least 50% waste oil. Preferably, cylinder oil produced by any of the methods described herein comprises up to 80% new cylinder oil, more preferably up to 60% new cylinder oil, even more preferably up to 40% new cylinder oil, and most preferably up to 35% new cylinder oil. In the cylinder oil produced by any of the methods described herein, preferably the amount of waste oil is at least 1%, and/or the amount of new cylinder oil is at least 1%. More preferably, the amount of waste oil is at least 1%, and/or the amount of new cylinder oil is at least 5%. Even more preferably, the amount of waste oil is at least 1%, and/or the amount of new cylinder oil is at least 10%. Most preferably, the amount of waste oil is at least 10%, and/or the amount of new cylinder oil is at least 10%. All amounts of used oil and new cylinder oil given herein are given as weight percent, based on the total amount of cylinder oil produced in the process described herein, unless otherwise indicated.

Another preferred method, particularly preferred as described above, is described herein, in which waste oil is obtained from equipment on board a ship. Oil is used extensively in various equipment on board ships. Disposal of waste oil is expensive. Therefore, if the waste oil could be reused as cylinder oil, disposal costs could be avoided. This description further describes another preferred method in which the method is performed on board a ship. Waste oil disposal is only possible at a port, and if the waste oil is consumed directly as cylinder oil, rather than transported to a plant that can produce it, the cost of storage facilities can be avoided.

Another aspect of the present invention is a method for operating an internal combustion engine comprising the steps of:

- preparing a cylinder oil according to any of the embodiments of the method for producing a cylinder oil as described above, and

- Using the cylinder oil in an internal combustion engine.

This method is particularly preferred, wherein the internal combustion engine is a two-stroke crosshead engine. Further preferably, the internal combustion engine of the method can be a four-stroke engine, in particular an auxiliary engine installed on a ship.

This method is further preferably wherein

- the internal combustion engine is a two-stroke crosshead engine or a four-stroke engine,

- the cylinder oil is used as a total loss cylinder oil, and

The waste oil comprises used system oil from a two-stroke crosshead engine or used system oil from a four-stroke engine. In this method, the used system oil from the two-stroke crosshead engine or used system oil from the four-stroke engine can be fully used to prepare cylinder oil according to the method of the present invention, thereby reducing storage and handling costs. The cylinder oil produced in this way can be precisely adjusted to the expected TBN value of the fuel used, and the viscosity of the produced cylinder oil approaches that of new cylinder oil. It is further preferred that any of the methods for operating an internal combustion engine described herein is installed on a ship.

Also preferred is any method for operating an internal combustion engine as described herein, wherein

- waste oil from at least one engine compartment or at least one storage tank,

- mixing of waste oil with new cylinder oil via a mixing device, and

- delivering cylinder oil to at least one cylinder of an internal combustion engine.

Waste oil, new cylinder oil, and the cylinder oil of this method can be of any type as described herein. In this method, equipment typically used with an internal combustion engine (e.g., an oil sump and cylinder) is preferably connected to the mixing device. Thus, a conventional internal combustion engine can be easily retrofitted with this system without significant expense and with a minimum of additional equipment, i.e., piping, agitators, and possibly pumps.

It is further preferred that any of the methods for operating an internal combustion engine as described herein, wherein the amount of waste oil and the mixed cylinder oil is determined based on the expected TBN value of the cylinder oil, the TBN value of the waste oil, and the TBN value of the new cylinder oil. This allows the production of cylinder oil with a precisely determined TBN value, thus allowing the cylinder oil to be adjusted to the fuel used.

Another aspect of the present invention is an apparatus for preparing cylinder oil, comprising a mixing device for mixing waste oil with new cylinder oil, the apparatus being characterized in that the mixing device is in fluid communication with:

- at least one internal combustion engine compartment designed to contain waste oil, or at least one storage tank designed to contain waste oil,

- at least one storage tank for new cylinder oil, and

- At least one cylinder of an internal combustion engine.

An internal combustion engine compartment designed to contain waste oil is any compartment that contains waste oil during normal engine operation or can contain waste oil and can be used to remove it. A storage compartment for fresh cylinder oil is any storage compartment that can accommodate cylinder oil. Furthermore, this device makes full use of equipment typically installed on internal combustion engines that use cylinder oil, such as an oil tank or internal combustion engine compartment and a storage tank for fresh cylinder oil. To prepare an internal combustion engine for operation using the method described herein, generally only a mixing device, piping, and possibly a pump must be installed. The piping and oil tank generally do not require additional heating devices or any other type of equipment.

Further preferred is an apparatus as described herein, further comprising:

- pumps for conveying waste oil to the mixing unit,

- a pump for delivering new cylinder oil to the mixing unit, and

- At least one storage tank for the prepared cylinder oil.

Also preferred is an apparatus as described herein, wherein the waste oil comprises used system oil from an internal combustion engine. As described above, the apparatus allows for optimal utilization of this used system oil and the production of cylinder oil having a precisely desired TBN value and a kinematic viscosity closer to the desired value than in prior art methods. Most preferred is an apparatus as described herein, wherein the internal combustion engine is a two-stroke crosshead engine or a four-stroke engine, in particular a four-stroke auxiliary engine installed on board a ship.

The device according to the invention can further comprise a system oil tank which is connected to the mixing device via a pipeline. This allows the use of new system oil instead of used system oil or the use of new system oil in addition to used system oil.

Another aspect of the invention is a vessel comprising an apparatus as described herein.

Another aspect of the invention relates to the use of waste oil and new cylinder oil for the preparation of cylinder oil.The waste oil and new cylinder oil used inventively and the cylinder oil resulting from the inventive use may be of any type described herein.

The method, apparatus and use of the present invention are particularly suitable for use with reciprocating internal combustion engines, and most preferably with two-stroke crosshead engines and/or with four-stroke (auxiliary) engines.Most preferably, the engine is mounted on a ship.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 depicts an example of an apparatus according to the invention.

FIG. 2 illustrates another embodiment of the apparatus of the present invention.

3 shows the graphs of the TBN value as a function of the amount of system oil in a cylinder oil produced according to the invention (graph B) and of the TBN value as a function of the amount of system oil in a cylinder oil produced according to the method described in EP 1 640 442 B1 (graph A).

DETAILED DESCRIPTION

FIG1 shows an internal combustion engine 1 having an oil sump 2 connected to a mixing device 5 via a conduit 3. The figure also shows a new cylinder reservoir 6 connected to the mixing device 5 via a conduit 7. The mixing device is also connected to a cylinder oil injection port in a cylinder 10 of the internal combustion engine 1 via a conduit 9. Conduits 3, 7, and 9 each include a valve 4, and conduit 9 also includes a pump 8. Valves 4 and pump 8 are connected to a controller 11.

In normal operation, the TBN value of the cylinder oil produced by mixing device 5 and flowing into conduit 9 is measured by an instrument known in the art (not shown), and an electrical signal is transmitted to controller 11. Controller 11 uses this signal to determine the amount of system oil from oil sump 2 and the amount of new cylinder oil from new cylinder reservoir 6 required to produce cylinder oil with a desired TBN value. Controller 11 controls valve 4 and pump 8 to supply the appropriate amount of cylinder oil with the appropriate TBN value to the oil injection port in cylinder 10 of internal combustion engine 1. In cases where the operation of internal combustion engine 1 requires cylinder oil with a very high TBN value, controller 11 can be programmed to supply 100% new cylinder oil to the cylinder oil injection port in cylinder 10 of internal combustion engine 1.

FIG2 shows an embodiment of the invention similar to FIG1 . The embodiment of FIG2 additionally includes a system oil tank 12 connected to a mixing device 5 via a conduit 14 including another valve 4. This allows new system oil to be used in place of, or in addition to, used system oil from the oil sump 2. The apparatus can also be equipped with additional conduits and valves that allow the controller 11 to replenish used system oil or system oil drained from the oil sump 2. FIG2 also shows a cylinder oil tank 13 that can be used to buffer cylinder oil production and usage.

The following examples illustrate the advantages of the present invention relative to the prior art for conventional cylinder oils. Table 1 shows the amounts of additives that must be mixed with commercially significant system oils with TBN values of 40 to 100, or with fresh cylinder oil, to achieve the desired TBN value. Column 3 of Table 1 lists the additives calculated based on the system known from EP 1 640 442 B1. NAVIGO 100MCL ^™ (available from Lukoil Marine, Hamburg, Germany) with a kinematic viscosity of 20 ^mm² /s at 100°C and a TBN of 100 was used as fresh cylinder oil. A commercially available system oil (i.e., NAVIGO 6SO) with a TBN of 6 and a kinematic viscosity of 11.5 ^mm² /s at 100°C was used as the system oil. A commercially available additive (i.e., Chevron OLOA 49805) with a TBN of 320 and a significant kinematic viscosity of 39 was used as the additive. The kinematic viscosity of this additive, measured at 100°C, is 101 ^mm² /s. However, this additive is a non-Newtonian fluid, and when diluted with oil, its flow properties differ from those of a Newtonian fluid. In the mixture with the system oil, the additive behaves as if it has a kinematic viscosity of 39 ^mm² /s at 100°C. Therefore, this latter value is used to calculate the resulting kinematic viscosity of the cylinder oil.

The resulting TBN value of the cylinder oil is a weighted average of the TBN value of the system oil used and the TBN value of the new cylinder oil used. The value of the amount of system oil necessary to achieve the desired TBN value has been calculated accordingly.

Table 1:

TBN value of a mixture of system oil and new cylinder oil or additives

Figure 3 graphically illustrates the same data as Table 1: TBN values as a function of the amount of system oil in the produced cylinder oil. As can be seen, for any commercially useful TBN value, if cylinder oil is produced according to the prior art (curve A), at least 70% of the system oil is required to achieve the desired TBN value. In contrast, according to the present invention (curve B), an amount of system oil ranging from 0% to approximately 64% is required. For a MAN B&W two-stroke crosshead engine with an 80 cm bore, when using heavy fuel oil (HFO) with a sulfur content of 3% by weight, a cylinder oil with a TBN of 70 and a kinematic viscosity of 17 is recommended at a feed rate of 0.6 g/kWh. To achieve a desired TBN value of 70, approximately 30% of the cylinder oil is required according to the present invention, while approximately 80% is required according to the prior art. For such engines, manufacturers recommend continuously refreshing the amount of system oil used in the engine to replenish the system oil and remove used system oil. Approximately 30% of the system oil used in the cylinder oil is used, depending on the amount of used system oil that must be continuously recovered from the engine. Therefore, the method according to the present invention uses approximately the same amount of used system oil that has accumulated from oil changes in the engine. In contrast, the method according to EP 1 640 442 B1 uses more than twice that amount, resulting in the use of virtually no system oil, which results in waste.

As discussed, for the aforementioned engine, a heavy fuel oil containing 3% sulfur by weight, a TBN value of 70, and a viscosity of 17 is recommended. Based on the amounts of system oil and fresh cylinder oil in the resulting cylinder oil, as well as the viscosity data for the system oil and fresh cylinder oil, the kinematic viscosity of the resulting cylinder oil can be calculated according to the Ubbelohde-Walther equation (see DIN 51563). For a mixture with a TBN value of 70, the viscosity is significantly lower than the recommended viscosity, namely, 14.3 ^mm² /s at 100°C for the mixture of system oil and additives and 16.6 ^{mm²/s at 100°C for the mixture of system oil and fresh cylinder oil. As can be seen, the cylinder oil produced according to the present invention has a kinematic viscosity that is almost identical to the target viscosity, namely, 16.6 mm² /s at 100°C, compared to the expected 17 mm² /} s at 100°C. In contrast, the kinematic viscosity of the cylinder oil produced according to the prior art has a viscosity much lower than the target viscosity, ie, 14.3 mm ² /s at 100° C. compared to 17 mm ² /s at 100° C.

As described above, because the viscosity of the oil film is too low for cylinder oils prepared according to the prior art, the oil film on the cylinder liner may not be continuous, and the cylinder or piston rings may come into direct contact with the cylinder liner, resulting in increased wear. Furthermore, as a result of the low oil film thickness, the alkalinity reserve of the oil film covering the liner surface is too low, because less oil contains fewer basic compounds per surface area (which results in a reduced alkalinity reserve), leading to a higher degree of corrosive wear. This also results in a reduced alkalinity reserve. As a result, the cylinder oil feed rate must be higher for cylinder oils prepared according to the prior art. Therefore, the present invention reduces wear, corrosion, and the amount of cylinder oil used, thereby benefiting the operation of the internal combustion engine compared to the prior art.

Reference Number List

1 Internal combustion engine

2 oil tanks

3 Pipeline

4 valves

5 Mixing device

6 New Cylinder Tanks

7 Pipeline

8 pumps

9 Pipeline

10 Cylinders of an internal combustion engine

11 Controller

12 System oil tank

13 Cylinder oil tank

14 Pipeline

Claims (17)

1. A method for producing cylinder oil, the method comprising the following steps: -Provide waste oil, - Provide new cylinder oil, and - Mix the waste oil with the new cylinder oil. The waste oil includes used system oil. The waste oil has a TBN value of less than or equal to 15. The waste oil has a kinematic viscosity of 7 ^mm² /s to 15 ^mm² /s at 100°C. The waste oil has a lower TBN value than the new cylinder oil. The new cylinder oil has a kinematic viscosity of 16 ^mm² /s to 24 ^mm² /s at 100°C, and The cylinder oil and the new cylinder oil are total loss cylinder oils used in crosshead diesel engines and include alkaline additives. 2. The method of claim 1, wherein the produced cylinder oil comprises at least 1% by weight of the waste oil based on the total amount of the produced cylinder oil, and/or at least 1% by weight of the new cylinder oil based on the total amount of the produced cylinder oil. 3. The method according to claim 1 or 2, wherein the generated cylinder oil comprises at least 10% by weight of the waste oil based on the total amount of cylinder oil produced, and/or at least 10% by weight of the new cylinder oil based on the total amount of cylinder oil produced. 4. The method according to claim 1 or 2, wherein the method is performed on a ship. 5. A method for operating an internal combustion engine, the method comprising the following steps: -Preparation of cylinder oil according to any one of the preceding claims, and - The cylinder oil is used in the internal combustion engine. 6. The method according to claim 5, wherein The internal combustion engine is a two-stroke crosshead engine. -Use the cylinder oil as a total loss cylinder oil, and Waste oil includes system oil used in the two-stroke crosshead engine. 7. The method according to claim 5 or 6, wherein - The waste oil comes from at least one engine compartment or at least one storage compartment. - The waste oil is mixed with the new cylinder oil using a mixing device, and - The cylinder oil is delivered to at least one cylinder of the internal combustion engine. 8. The method according to claim 5 or 6, wherein the amount of waste oil and new cylinder oil mixed is determined by the expected TBN value of the cylinder oil, the TBN value of the waste oil, and the TBN value of the new cylinder oil. 9. The method according to claim 5 or 6, wherein the TBN value of the new cylinder oil is 10 or greater. 10. The method according to claim 5 or 6, wherein the TBN value of the new cylinder oil is 50 or greater. 11. The method according to claim 5 or 6, wherein the TBN value of the new cylinder oil is 80 or greater. 12. The method according to claim 5 or 6, wherein the TBN value of the new cylinder oil is 90 or greater. 13. The method according to claim 5 or 6, wherein the TBN value of the new cylinder oil is 100 or greater. 14. An apparatus for preparing cylinder oil, the apparatus comprising: -A mixing device (5) for mixing waste oil and new cylinder oil. - An internal combustion engine (1) including at least one cylinder (10), -The internal combustion engine (1) having at least one compartment (2) containing waste oil or at least one storage compartment containing waste oil, and -At least one storage compartment (6) for new cylinder oil, The characteristic feature is that the mixing device (5) is in fluid communication with the following device: -The internal combustion engine (1) having at least one compartment (2) containing waste oil or the at least one storage compartment containing waste oil. -At least one of the aforementioned storage compartments (6) for new cylinder oil, and -The at least one cylinder of the internal combustion engine (1), The internal combustion engine (1) is a two-stroke crosshead engine, the storage compartment (6) for new cylinder oil includes new cylinder oil, and the cylinder oil and the new cylinder oil are as defined in claim 1 or 2. 15. The apparatus of claim 14, further comprising: - A pump for conveying the waste oil to the mixing device (5), - A pump for delivering the new cylinder oil to the mixing device (5), and - At least one storage compartment (13) for the prepared cylinder oil. 16. A ship comprising the equipment according to claim 14 or 15. 17. The use of waste oil and new cylinder oil, wherein the waste oil and new cylinder oil are used to prepare cylinder oil according to the method defined in claim 1 or 2.