HK40000954A - Process and apparatus for the production of a cylinder oil and related method, ship and use - Google Patents

Description

Method and apparatus for preparing cylinder oil and related method, vessel and use

The present application is a divisional application of a patent application having an application date of 2014, 18/2, application number 201480009457.7 entitled "method and apparatus for preparing cylinder oil" (corresponding international application PCT/EP 2014/053132).

Technical Field

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

-providing a used oil,

-providing new cylinder oil, and

-mixing the used oil with fresh cylinder oil,

wherein the used oil has a lower TBN than the fresh cylinder oil.

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

-preparing a cylinder oil according to the process for preparing a cylinder oil described herein, and

-using the cylinder oil in an internal combustion engine.

The invention also relates to an apparatus for preparing cylinder oil, comprising a mixing device for mixing used oil with fresh 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 compartment containing waste oil,

at least one storage tank for fresh cylinder oil, and

-at least one engine cylinder.

Another aspect of the invention relates to the use of used oil and virgin cylinder oil for the preparation of cylinder oil.

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

Background

Cylinder oil is an oil that is commonly used to lubricate cylinders in internal combustion engines. The cylinder oil has multiple functions. The main function of the cylinder oil is to provide lubrication between the cylinder and/or piston rings and the cylinder liner. The purpose of the cylinder oil is therefore wear control. Another important function of cylinder oil is to prevent corrosion of the material of the cylinder and of the liner or wall of the combustion chamber. The cylinder oil itself should be stable against thermal decomposition, and the cylinder oil should have good oxidation resistance, good anti-foaming properties, and good water emulsifiability. Pressure performance is also important for cylinder oil.

Most of these properties of cylinder oils are controlled by additives. Kinematic viscosity (kinematical viscosity) is controlled primarily by the composition of the oil itself. Hydrocarbons with long carbon chains and hydrocarbons with branched carbon chains tend to have higher kinematic viscosities. The cylinder oil is imparted with corrosion-preventing properties mainly by adding a basic organic compound (e.g., amine, etc.). Organic diimines (organic di-imines) as described in GB 1,183,345 a are mainly used as additives in cylinder oils to control anti-corrosion properties. The basic additive neutralizes acids (e.g., sulfuric acid and other acids) formed from sulfur or sulfur-containing compounds contained in the fuel during combustion in the combustion chamber. The cylinder oil may comprise 0.1 to 30% by weight of these diimines. Another example of a suitable additive that enhances wear and corrosion resistance is alkylamine-alkylphosphonates, as disclosed in US2004/144355 a.

For some lubrication applications (e.g., in lubricated cylinders in crosshead diesel engines that employ full loss lubrication systems and burn heavy fuel oil with widely varying sulfur content), this large degree of engine lubrication demand and with sufficient frequency of changes makes one lubricant formulation unable to provide adequate performance over the entire operating range. This inability results in at least increased engine maintenance requirements and more commonly unnecessary expenses due to maintenance costs, down time and excessive fuel consumption. Thus, there is a need to be able to vary the composition of the lubricant in response to the actual lubrication needs of the engine. US2004/144355a proposes a system in which additives are added to the primary lubricant to tailor the corrosion resistance properties to the fuel and engine conditions. The use of waste oils is not disclosed in the literature.

The cylinder typically wears to a greater extent than other parts of the engine, which has a higher temperature and the combustion process imposes further harsh conditions on the cylinder oil. Therefore, the cylinder oil is usually more contaminated than the oil in the rest of the engine (so-called system oil). In engines where the system oil is integrated with or in contact with the cylinder oil, the cylinders carry a significant amount of contaminants into the system oil. In large engines, which can use tens of thousands of liters of system oil, the cylinder oil and the system oil are thus usually separated to prevent contamination of the system oil. In such systems, cylinder oil cannot be regenerated by mixing with system oil. Therefore, the quality of the cylinder oil is rapidly deteriorated. In order to maintain a sufficient quality of the cylinder oil, the cylinder oil must be exchanged often, or used only once by operating in a so-called "full loss" lubrication system. In a full loss system, the cost of system oil is reduced, but the cost of cylinder oil is still high. EP 1640442B 1 proposes a system in which used system oil of an engine is mixed with an additive to produce cylinder oil. Such a system uses waste oil to prepare cylinder oil, thereby reducing costs and environmental problems. While this system provides adequate control of the corrosion performance of the cylinder oil produced and can utilize excess conventional cylinder oil, it also has disadvantages. The cylinder oil prepared by this method has much lower kinematic viscosity and thus has poorer lubricating properties than general cylinder oils. Therefore, such cylinder oil must be used in large amounts to provide the same lubricating performance. Therefore, this reduces the effect of the reduction in fuel consumption.

In addition, the additives used have a very high transportKinematic viscosity, generally close to 100mm at 100 ℃ or higher²And s. If the liquid is to be kept warm, this liquid can only be moved by means of a pump. Therefore, tanks, pipes, mixers and other equipment in contact with the additives need to be equipped with heaters. In cold climates, equipment such as tankers that deliver the additive to ships or other equipment in contact with the additive also needs to be equipped with heaters or good insulation. Therefore, when cylinder oils are manufactured in situ using such additives, logistics is a major problem. In addition to the logistics, there is always the risk of local overheating, which is liable to occur and contributes to the oxidation of the additive, which would significantly reduce the quality of the additive and thus affect the quality of the cylinder oil produced.

Disclosure of Invention

It is an object of the present invention to provide a system for reducing the amount of lubricant used in an internal combustion engine, in particular the amount of cylinder oil and/or system oil. Meanwhile, the present invention is directed to providing a method and apparatus that can better control kinematic viscosity when preparing cylinder oil from waste oil. It is another object of the invention to improve wear and corrosion.

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

-providing a used oil,

-providing new cylinder oil, and

-mixing the used oil with fresh cylinder oil,

wherein the used oil has a lower TBN than fresh cylinder oil.

The method allows the reuse of used oil as cylinder oil, thereby reducing costs and reducing environmental problems. The method also provides a partially recovered cylinder oil having a higher kinematic viscosity than the methods described in the prior art, i.e. the kinematic viscosity of the partially recovered cylinder oil is closer to that of a typical cylinder oil. The mixing of waste oil with cylinder oil has an unexpected advantageous effect, especially for the mixing of system oil and cylinder oil, since the general purpose of cylinder oil is only available when the system oil is separated from the cylinder oil. Therefore, mixing these oils to produce cylinder oil has never been considered before the present invention.

According to the invention, the cylinder oil is an oil designed for lubrication of cylinders in an internal combustion engine. The cylinder oil preferably comprises an alkaline (i.e. alkali-containing) additive. Preferably, the cylinder oil prepared 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 for use in a crosshead diesel engine, in particular a two-stroke crosshead diesel engine, in particular a diesel engine mounted on a vessel, such as a ship. However, the engine may also be mounted in a stationary system. Alternatively, it is preferred that the cylinder oil is designed for use in a four-stroke diesel engine with or without a crosshead, in particular a diesel engine mounted on a vessel (e.g. a ship). Such an engine may for example be an auxiliary engine on a ship for generating energy in combination with a generator or the like.

Further preferably, the used oil at least partly comprises used system oil from at least one diesel crosshead engine employing a total loss lubrication system for the cylinders. Most preferably, however, the internal combustion engine is mounted on a ship and the method is performed on the ship. Further preferably, the engine is a crosshead diesel engine employing a full loss lubrication system for the cylinders.

In the context of the present invention, the expression "fresh cylinder oil" means cylinder oil free from untreated used oil. However, the new cylinder oil may include a regenerated oil (i.e., a circulating oil) that has been processed in the factory. These examples are cylinder oils which are generally commercially available. Preferably, the cylinder oil used in the present invention has a high TBN value and a high viscosity. Particularly useful is a resin having a thickness of 20mm at 100 deg.C²Kinematic viscosity/s and NAVIGO100MCL with TBN value of 100^TM(available from Luke Marine lubricating oils, Hamburg, Germany, LUKOIL Marine Lubricants) which is the only commercially availableA cylinder oil having a TBN value of 100 or more.

In the context of the present invention, the word "used oil" means oil that has been used for any type of lubrication or for other purposes, or includes such oil. Used oil may have been used as such oil, or used oil may contain oil that has been used. It is particularly preferred to use waste oils which are otherwise treated.

One factor to consider for 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, resulting in increased wear. Another important factor for avoiding corrosive wear is the alkalinity reserve (aikalinity reserve) remaining in the oil film on the cylinder surface. As the piston moves downward, the cylinder surfaces are exposed to a corrosive environment that causes corrosive wear. The thickness of the oil film remaining on the cylinder surface depends on the kinematic viscosity of the cylinder oil. The thinner the cylinder oil, the smaller the oil film thickness and alkalinity reserve of the oil film covering the cylinder surface, since less oil contains less basic compounds per surface area, resulting in a higher level of corrosive wear. If the kinematic viscosity is too high, the friction is too high, resulting in a loss of performance of the engine and an excess of alkalinity reserve, which can form additional deposits on the upper piston area and on the back of the piston rings, resulting in higher wear levels or scuffing.

For the purposes of the present invention, all values of the kinematic viscosity are measured in accordance with DIN 51562/2. All values of kinematic viscosity described herein are therefore kinematic viscosity at 100 ℃ as described in DIN 51562/2.

The cylinder oil of the present invention preferably has a viscosity of 14mm at 100 deg.C²A kinematic viscosity of 15mm at 100 ℃ or more²A kinematic viscosity of 16mm at 100 ℃ or more²A kinematic viscosity of 17mm at 100 ℃ or more²A kinematic viscosity of/s or greater. The new cylinder oil of the present invention preferably has a viscosity of 16mm at 100 deg.C²A kinematic viscosity of 18mm at 100 ℃ or more²A kinematic viscosity of 19mm at 100 ℃ or more²A kinematic viscosity of/s or greater. Kinematic viscosity of fresh cylinder oil at 100 deg.C preferably at from 16mm²S to 24mm²In the range of/s, more preferably from 18mm at 100 ℃ and²s to 22mm²In the range of/s, most preferably at 100 ℃ preferably from 19mm²S to 21mm²In the range of/s. The waste oil of the process of the invention may have a thickness of up to 25mm²Kinematic viscosity in/s. The used oil of the process of the invention preferably has a size ranging from 7mm²S to 15mm²Kinematic viscosity in/s, more preferably in the range from 8mm²S to 13mm²S, even more preferably in the range from 9mm²S to 12.5mm²S, most preferably in the range of from 10mm²S to 12.5mm²And s. Preferably a process as described herein, wherein the used oil has a lower kinematic viscosity than the cylinder oil.

One parameter that determines the corrosion protection properties of cylinder oils is the TBN value (also called BN value or neutralization value). TBN is an abbreviation for "total base number" which defines the stoichiometric equivalent in milligrams of KOH as the amount of acid necessary to neutralize the total base content contained in a 1 gram sample. For purposes of the description herein, TBN values are determined as described in ASTM D2896.

The TBN value of the cylinder oil prepared by any of the methods of the present invention is preferably suitable for the sulphur content of the fuel used in an internal combustion engine according to the methods known in the art. Background art for this method is disclosed, for example, in US2004/144355A, and this patent is incorporated herein by reference.

The cylinder oil prepared by any of the methods described herein preferably has a TBN value of 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 is preferably also 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. Used oils generally have a TBN of 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 oil used in the present invention has a high TBN value and a high viscosity. Typically, the new cylinder oil used in the method of the present invention as described herein has a TBN value of 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, most preferably greater than or equal to 100. It may also be preferred to use a new cylinder oil having a TBN value less than or equal to 50, less than or equal to 40, or less than or equal to 25.

Mixing of the used oil with the fresh cylinder oil to mix the oils may be accomplished by any means known to those skilled in the art, however, it is preferred to mix in a fixed mixing duct, mixing tube or in-tube mixing unit. Useful static mixers that can be used in the present invention are described, for example, in US 8,147,124. Alternatively, batch mixing can be performed in a separate tank equipped with a stirrer.

Another method as described herein is also preferred, wherein the used 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 used oil comprises used system oil. More preferably, the used oil consists of used system oil.

The cylinder oil prepared by any of the processes described herein typically comprises at least 2% used oil, preferably at least 5% used oil, more preferably at least 10% used oil. Even more preferably, the cylinder oil prepared by any of the processes described herein comprises at least 20% used oil, most preferably at least 30% used oil. The cylinder oil prepared by any of the processes described herein may comprise at least 40% used oil, or at least 50% used oil. Preferably, the cylinder oil prepared by any of the processes described herein comprises at most 60% used oil, more preferably at most 50% used oil, even more preferably at most 40% used oil, most preferably at most 30% used oil. The amount of used oil in the cylinder oil prepared 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%.

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

Another preferred process is also described herein, in particular as preferred above, wherein the waste oil is obtained from a shipboard installation. Oil is used in large quantities in a variety of equipment on ships. The disposal of used oils is expensive. Therefore, if the used oil can be reused as cylinder oil, the cost of disposal can be avoided. The description herein further describes another preferred method, wherein the method is performed on a vessel. The treatment of waste oil is only possible at port and the cost of storage facilities can be avoided if the waste oil is consumed directly as cylinder oil, without being transported to a plant or the like where cylinder oil can be produced from the waste oil.

Another aspect of the 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 preparing a cylinder oil as described above, and

-using the cylinder oil in an internal combustion engine.

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

Such a method is further preferred, wherein

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

cylinder oil as total loss cylinder oil, and

the used oil comprises used system oil of a two-stroke crosshead engine or used system oil of a four-stroke engine, respectively. In this method, the used system oil of a two-stroke crosshead engine or the used system oil of a four-stroke engine, respectively, can be completely used for preparing the cylinder oil according to the method of the invention, and storage costs and disposal costs can be saved. The expected TBN value of the fuel used can be precisely adjusted for the cylinder oil prepared in this way, and the viscosity of the prepared cylinder oil is close to that of fresh cylinder oil. Any of the methods for operating an internal combustion engine as described herein is further preferred, wherein the two-stroke crosshead engine and/or the four-stroke engine, respectively, is mounted on a vessel.

Any of the methods for operating an internal combustion engine as described herein are also preferred, wherein

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

-mixing the used oil with fresh cylinder oil by means of a mixing device, and

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

The used oil, fresh cylinder oil, and cylinder oil of this process may be of any type as described herein. In this method, the equipment normally used with internal combustion engines (e.g., oil sump and cylinder) is preferably connected to a mixing device. Thus, a conventional internal combustion engine can be simply retrofitted with this system, without significant expense and with a minimum amount of additional equipment, i.e., piping, agitators, and may be pumps.

Any of the methods for operating an internal combustion engine as described herein is further preferred, wherein the amount of used oil and cylinder oil mixed is determined by the expected TBN value of the cylinder oil, the TBN value of the used oil and the TBN value of the fresh cylinder oil. This allows the production of cylinder oil with a precisely determined TBN value and thus allows the cylinder oil to be adjusted to the fuel used.

Another aspect of the invention is an apparatus for preparing cylinder oil comprising mixing means for mixing used oil with fresh cylinder oil, characterized in that the mixing means are in fluid communication with:

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

at least one storage tank for fresh cylinder oil, and

-at least one cylinder of an internal combustion engine.

An engine compartment designed to contain waste oil is one that contains waste oil in normal operation of the engine or that can contain waste oil and that can be used to remove the waste oil. The storage tank for fresh cylinder oil is any storage tank that can hold cylinder oil. Furthermore, this device makes full use of devices which are usually installed at internal combustion engines using cylinder oil, such as oil sumps or engine compartments, and storage tanks for fresh cylinder oil. In order to prepare an internal combustion engine for operation using the method described herein, it is generally only necessary to install mixing devices, pipes and possibly pumps. The pipes and tanks usually do not require additional heating devices or any other type of equipment.

Further preferred as described herein is an apparatus further comprising:

-a pump for feeding the used oil to the mixing device,

-a pump for delivering fresh cylinder oil to the mixing device, and

-at least one storage compartment for the prepared cylinder oil.

Also preferred as described herein is an apparatus wherein the used oil comprises used system oil of an internal combustion engine. As mentioned above, the apparatus allows for optimal use of the used system oil for an equivalent process and for the production of cylinder oil having exactly the desired TBN value and the kinematic viscosity of which is closer to the desired value than that of the prior art process. Most preferred as described herein is an apparatus wherein the internal combustion engine is a two-stroke crosshead engine or a four-stroke engine, in particular a four-stroke auxiliary engine mounted on a ship.

The apparatus according to the invention may additionally comprise a system tank, which is connected to the mixing device by means of a pipe. This allows replacing the used system oil with a new system oil or using a new system oil in addition to the 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 used oil and virgin cylinder oil for the preparation of cylinder oil. The used and fresh cylinder oils for inventive use and the cylinder oils resulting from inventive use can be of any of the types described herein.

The method, apparatus and application 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.

Drawings

Fig. 1 depicts an example of the apparatus of the present invention.

Fig. 2 depicts another example of the apparatus of the present invention.

The curves of fig. 3 show the TBN value as a function of the amount of system oil in cylinder oil prepared according to the invention (curve B) and the TBN value as a function of the amount of system oil in cylinder oil prepared according to the method described in EP 1640442B 1 (curve a).

Detailed Description

Fig. 1 shows an internal combustion engine 1 with an oil sump 2, which is connected to a mixing device 5 via a line 3. The figure also shows a new cylinder tank 6 connected to the mixing device 5 via a conduit 7. The mixing device is also connected via a conduit 9 with a cylinder oil injection port in a cylinder 10 of the combustion engine 1. The conduits 3, 7 and 9 each comprise a valve 4, and the conduit 9 further comprises a pump 8. The valve 4 and the pump 8 are connected to a controller 11.

In a general mode of operation, the TBN value of the cylinder oil produced by the mixing device 5 and flowing into the conduit 9 is measured by instrumentation (not shown) known in the art and an electrical signal is sent to the controller 11. The controller 11 uses the signal to determine the amount of system oil from the oil sump 2 and the amount of new cylinder oil from the new cylinder reservoir 6 that are required to produce cylinder oil having the desired TBN value. The controller 11 controls the valve 4 and the pump 8 to supply an appropriate amount of cylinder oil having an appropriate TBN value to an oil filling port in the cylinder 10 of the internal combustion engine 1. For the case where operation of the internal combustion engine 1 requires cylinder oil with a very high TBN value, the controller 11 may be programmed such that 100% of the new cylinder oil is provided to the cylinder oil injection port in the cylinder 10 of the internal combustion engine 1.

Fig. 2 shows an embodiment of the invention similar to that of fig. 1. The embodiment of fig. 2 additionally has a system tank 12 which is connected to the mixing device 5 via a line 14 which comprises a further valve 4. This allows replacing the used system oil from the oil sump 2 with new system oil or using new system oil in addition to the used system oil. The apparatus may also be equipped with additional piping and valves that will allow the controller 11 to replenish the used system oil or the system oil drained from the oil sump 2. Figure 2 also shows a cylinder oil tank 13 that can be used to buffer the production and use of cylinder oil.

The following examples will demonstrate the advantages of the present invention relative to the prior art of conventional examples for cylinder oil. Table 1 shows the amount of TBN value system oil 40 to 100 that must be mixed with additives or with fresh cylinder oil, respectively, to achieve the desired TBN value, which is commercially important. Column 3 of table 1 is the additive calculated according to the system known from EP 1640442B 1. Has been used with a thickness of 20mm at 100 deg.C²Kinematic viscosity/s and NAVIGO100MCL with TBN value of 100^TM(available from Luck Marine lubricating oil, Hamburg, Germany) as new cylinder oil. Have been used with a TBN value of 6 and 11.5mm at 100 deg.C²A commercially available system oil of kinematic viscosity per second (i.e., NAVIGO6SO) was used as the system oil. Commercially available additives having a TBN value of 320 and a significant kinematic viscosity of 39, namely Chevron OLOA 49805, have been used as additives. The kinematic viscosity of the additive, measured at 100 ℃, is 101mm²And s. However, this additive is a non-newtonian fluid and, when diluted with oil, has flow properties that differ from those of newtonian fluids. In the mixture with the system oil, the additive appeared as if it had 39mm at 100 deg.C²The kinematic viscosity in/s is the same. The latter value is therefore used to calculate the kinematic viscosity of the cylinder oil produced.

The TBN value of the cylinder oil produced 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 reach the desired TBN value has been calculated accordingly.

Table 1:

TBN of mixture of system oil and new cylinder oil or additive

Fig. 3 shows the same data as table 1, i.e. the TBN value as a function of the amount of system oil in the cylinder oil produced, in the form of a curve. As can be seen, for any commercially useful TBN value, if the cylinder oil is produced according to the prior art (curve a), at least 70% of the amount of system oil is necessary to achieve the desired TBN value. In contrast, according to the present invention (curve B), an amount of 0% to about 64% of system oil is necessary. For a MAN B & W two-stroke crosshead engine with an 80cm bore, a cylinder oil with a TBN value of 70 and a kinematic viscosity of 17 is recommended at a feed rate of 0.6g/kWh when using Heavy Fuel Oil (HFO) with a sulphur content of 3% by weight. For a TBN value of 70 to be expected, about 30% of the cylinder oil is necessary according to the present invention, and about 80% is necessary according to the prior art. For such engines, manufacturers recommend continuously renewing a certain amount of system oil used in the engine to replenish the system oil and remove the used system oil. Approximately 30% of the system oil in the cylinder oil will be used depending on the amount of used system oil that is continuously recovered from the engine as needed. The method according to the invention thus uses about the same amount of used system oil, which is accumulated when exchanging from the oil in the engine. In contrast, the method according to EP 1640442B 1 uses more than twice the amount, resulting in the use of almost unused system oil, thus generating waste.

As discussed, for the engine described aboveHeavy fuel oils containing 3% by weight of sulphur, a TBN value of 70 and a viscosity of 17 are recommended. From the amounts of system oil and fresh cylinder oil in the produced cylinder oil, and the viscosity data of the system oil and fresh cylinder oil, the kinematic viscosity of the produced cylinder oil can be calculated according to the ukrainer equation (see DIN 51563). For the mixture with a TBN value of 70, the viscosity is significantly lower than the recommended viscosity, i.e. 14.3mm at 100 ℃ for the mixture of system oil and additives²S, 16.6mm at 100 ℃ for a mixture of system oil and fresh cylinder oil²And s. As can be seen, the cylinder oil prepared according to the invention has a kinematic viscosity almost identical to the target viscosity, i.e. 17mm as expected at 100 ℃²The ratio/s at 100 ℃ is 16.6mm²And s. In contrast, the kinematic viscosity of the cylinder oil produced according to the prior art has a much lower viscosity than the target viscosity, i.e. 17mm at 100 ℃²The ratio/s at 100 ℃ is 14.3mm²/s。

As described above, because the viscosity of the oil film is too low for the cylinder oil prepared according to the prior art, the oil film on the cylinder liner may not be continuous, and the cylinder or piston rings may be in direct contact with the cylinder liner, resulting in increased wear. Moreover, as a result of the low oil film thickness, the alkalinity reserve of the oil film covering the bushing surface is too low, since less oil contains fewer basic compounds per surface area (which results in a reduced alkalinity reserve), resulting in a higher level of corrosive wear. This also leads to a reduced alkalinity reserve. The result is that the cylinder oil feed rate must be higher for cylinder oils prepared according to the prior art. Thus, the present invention reduces wear, corrosion and the amount of cylinder oil used, thereby being advantageous over the prior art in the operation of an internal combustion engine.

List of reference numerals

1 internal combustion engine

2 oil groove

3 pipeline

4 valve

5 mixing device

6 new cylinder storage tank

7 pipeline

8 pump

9 pipeline

10 cylinder of internal combustion engine

11 controller

12 system oil tank

13 cylinder oil tank

14 pipeline

Claims (15)

1. A process for preparing a cylinder oil, the process comprising the steps of:

-providing a new system oil,

-providing new cylinder oil, and

-mixing the new system oil with the new cylinder oil,

wherein the new system oil has a lower TBN value than the new cylinder oil, and wherein the cylinder oil and the new cylinder oil are all-loss cylinder oils for use in a crosshead diesel engine and comprising basic additives.

2. The method according to claim 1, wherein the prepared cylinder oil comprises at least 1% by weight of the new system oil, based on the total amount of cylinder oil prepared, and/or at least 1% by weight of the new cylinder oil, based on the total amount of cylinder oil prepared.

3. The method according to claim 1 or 2, wherein the prepared cylinder oil comprises at least 10% by weight of the new system oil, based on the total amount of cylinder oil prepared, and/or at least 10% by weight of the new cylinder oil, based on the total amount of cylinder oil prepared.

4. The method of claim 1, 2 or 3, wherein the new system oil has a lower kinematic viscosity than the cylinder oil.

5. The method according to any of the preceding claims, wherein one or more oils are selected for use in addition to the new system oil from the group comprising: 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.

6. The method according to any of the preceding claims, wherein the method is performed on a vessel.

7. Method for operating an internal combustion engine, the method comprising the steps of:

-preparing a cylinder oil according to any one of the preceding claims, and

-using the cylinder oil in the internal combustion engine.

8. The method of claim 7, wherein

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

-using the cylinder oil as a total loss cylinder oil, and

-the new system oil comprises the system oil used by the two-stroke crosshead engine.

9. The method of claim 7 or 8, wherein

-the new system oil comes from at least one engine compartment or at least one storage compartment,

-mixing the new system oil with the new cylinder oil by means of a mixing device, and

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

10. Method according to any of the preceding claims, wherein the amount of the new system oil and the new cylinder oil mixed is determined by the TBN value expected for the cylinder oil, the TBN value of the new system oil and the TBN value of the new cylinder oil.

11. A method according to any preceding claim, wherein the new cylinder oil has a TBN value of 10 or greater, preferably 50 or greater, more preferably 80 or greater, even more preferably 90 or greater and most preferably 100 or greater.

12. An apparatus for preparing cylinder oil, the apparatus comprising:

-a mixing device (5) for mixing new system oil and new cylinder oil,

-an internal combustion engine (1) comprising at least one cylinder (10),

-at least one tank (2) of the internal combustion engine (1) containing the new system oil or at least one storage tank containing the new system oil, and

-at least one storage compartment (6) for said fresh cylinder oil,

characterized in that said mixing device (5) is in fluid communication with:

-the at least one tank (2) of the internal combustion engine (1) containing the new system oil or the at least one storage tank containing the new system oil,

-the at least one storage compartment (6) for said fresh cylinder oil, and

-the at least one cylinder of the internal combustion engine (1),

wherein the internal combustion engine (1) is a two-stroke crosshead engine, wherein the at least one storage compartment (6) for the fresh cylinder oil comprises the fresh cylinder oil, and wherein the cylinder oil and the fresh cylinder oil are as defined in any one of claims 1 to 5 or as defined in claim 11.

13. The apparatus of claim 12, the apparatus further comprising:

-a pump for conveying the new system oil to the mixing device (5),

-a pump for delivering said fresh cylinder oil to said mixing device (5), and

-at least one storage compartment (13) for the prepared cylinder oil.

14. A ship comprising an apparatus according to claim 12 or 13.

15. Use of a new system oil and a new cylinder oil for the preparation of a cylinder oil, wherein the new system oil, the cylinder oil and the new cylinder oil are as defined in any one of claims 1 to 5 or as defined in claim 11.