Process and apparatus for the preparation of a cylinder oil

Abstract

A process for production of cylinder oil comprises providing used oil, providing fresh cylinder oil, and blending the used oil with the fresh cylinder oil. The used oil has a lower TBN value than the fresh cylinder oil. A process for the operation of an internal combustion engine comprises preparing cylinder oil as described and using the cylinder oil in the internal combustion engine. An apparatus for the preparation of a cylinder oil comprises a blending means for blending used oil and fresh cylinder oil. The blending means is in flow communication with at least one compartment of an internal combustion engine that comprises used oil or at least one storage compartment comprising used oil, at least one storage compartment for fresh cylinder oil, and at least one cylinder of an internal combustion engine. Used oil and fresh cylinder oil are used for the preparation of cylinder oil.

Claims

1. Process for the production of a cylinder oil having a total base number (TBN) value of 30 or more and adapted for use in a two-stroke crosshead internal combustion engine, comprising the steps: providing a used oil in a first compartment, providing a fresh cylinder oil in a second compartment, and blending the used oil with the fresh cylinder oil in a blending apparatus to prepare the cylinder oil having a TBN value of 30 or more, wherein the used oil has a lower TBN value than the fresh cylinder oil.

2. Process according to claim 1, wherein the cylinder oil produced comprises at least 1% by weight used oil, based on the total amount of cylinder oil produced and/or at least 1% by weight of fresh cylinder oil, based on the total amount of cylinder oil produced.

3. Process according to claim 1, wherein the cylinder oil produced comprises at least 10% by weight used oil, based on the total amount of cylinder oil produced and/or at least 10% by weight of fresh cylinder oil, based on the total amount of cylinder oil produced.

4. Process according to claim 1, wherein the used oil has a lower kinematic viscosity than the cylinder oil.

5. Process according to claim 1, wherein the used oil comprises one or more oils selected from the group consisting of used hydraulic fluids, used gear oils, used system oils, used trunk piston engine oils, used turbine oils, used heavy duty diesel oils, used compressor oils and mixtures thereof.

6. Process according to claim 1, wherein the process is performed on a marine vessel.

7. Process according to claim 1, wherein the amount of used oil and fresh cylinder oil blended is determined by the TBN value desired for the cylinder oil, the TBN value of the used oil and the TBN value of the fresh cylinder oil.

8. Process according to claim 1, wherein the fresh cylinder oil has a TBN value of 50 or more.

9. Process according to claim 1, wherein the fresh cylinder oil has a TBN value of 80 or more.

10. Process according to claim 1, wherein the fresh cylinder oil has a TBN value of 90 or more.

11. Process according to claim 1, wherein the fresh cylinder oil has a TBN value of 100 or more.

12. Process according to claim 1, wherein the used cylinder oil has a TBN value of less than 30.

13. Process according to claim 1, wherein the used cylinder oil has a TBN value of less than 30 and the fresh cylinder oil has a TBN value of 80 or more.

14. Process according to claim 1, wherein the used cylinder oil has a TBN value of less than 15 and the fresh cylinder oil has a TBN value of 80 or more.

15. Process for the operation of a two-stroke crosshead internal combustion engine comprising the steps of: preparing a cylinder oil having a total base number (TBN) value of 30 or more using a process for the production of a cylinder oil, said process for the production of a cylinder oil comprising the steps: providing a used oil in a first compartment, providing a fresh cylinder oil in a second compartment, and blending the used oil with the fresh cylinder oil in a blending apparatus to prepare the cylinder oil having a TBN value of 30 or more, wherein the used oil has a lower TBN value than the fresh cylinder oil, and using the cylinder oil in the internal combustion engine.

16. Process according to claim 15, wherein the cylinder oil is used as an all-loss cylinder oil, and the used oil comprises used system oil of the two-stroke crosshead engine.

17. Process according to claim 15, wherein the used oil is derived from at least one engine compartment, and the cylinder oil is delivered to at least one cylinder of the internal combustion engine.

18. Process according to claim 15, wherein the amount of used oil and fresh cylinder oil blended is determined by the TBN value desired for the cylinder oil, the TBN value of the used oil and the TBN value of the fresh cylinder oil.

19. Apparatus for the preparation of a cylinder oil having a total base number (TBN) value of 30 or more, comprising a blending apparatus for blending used oil and fresh cylinder oil, wherein the blending apparatus is in flow communication with at least one compartment of a two-stroke crosshead internal combustion engine that comprises used oil or at least one storage compartment comprising used oil, at least one storage compartment that comprises fresh cylinder oil, and at least one cylinder of the internal combustion engine.

20. Apparatus according to claim 19, comprising additionally a pump for the transport of used oil to the blending apparatus, a pump for the transport of the fresh cylinder oil to the blending apparatus, and at least one storage compartment for the prepared cylinder oil.

21. Ship comprising an apparatus for the preparation of a cylinder oil having a total base number (TBN) value of 30 or more, comprising a blending apparatus for blending used oil and fresh cylinder oil, wherein the blending apparatus is in flow communication with at least one compartment of a two-stroke crosshead internal combustion engine that comprises used oil or at least one storage compartment comprising used oil, at least one storage compartment that comprises fresh cylinder oil, and at least one cylinder of the internal combustion engine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1: FIG. 1 describes an example for an apparatus of the present invention.

(2) FIG. 2: FIG. 2 describes another example for an apparatus of the present invention.

(3) FIG. 3: The graph of FIG. 3 shows the TBN value as a function of the amount of system oil in the cylinder oil prepared according to the present invention (Graph B) and according to the method described in EP 1 640 442 B1 (Graph A).

DETAILED DESCRIPTION OF THE DRAWINGS

(4) FIG. 1 shows an internal combustion engine 1 with an oil sump 2, which is connected via piping 3 with blending means 5. It further shows a fresh cylinder storage tank 6 connected via piping 7 with the blending means 5. The blending means is further connected via piping 9 to the cylinder oil injection openings in the cylinder 10 of internal combustion engine 1. Pipings 3, 7 and 9 each comprise a valve 4 and piping 9 further comprises a pump 8. The valves 4 and the pump 8 are connected to a controller 11.

(5) In usual operation mode, the TBN value of the cylinder oil produced by the blending means 5 and flowing into piping 9 is measured by an instrument known in the art (not shown) and an electrical signal is submitted 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 fresh cylinder oil from the fresh cylinder storage tank 6 that are needed to produce the cylinder oil with the TBN value required. The controller 11 controls the valves 4 and the pump 8 in order to provide the correct amount of cylinder oil with the correct TBN value to the oil injection openings in the cylinder 10 of internal combustion engine 1. For the case that a cylinder oil with very high TBN value is required for the operation of the internal combustion engine 1, controller 11 can be programmed such that 100% fresh cylinder oil is provided to the cylinder oil injection openings in the cylinder 10 of internal combustion engine 1.

(6) FIG. 2 depicts a similar embodiment of the present invention as FIG. 1. The embodiment of FIG. 2 has additionally a system oil tank 12, which is connected, by piping 14, which comprises a further valve 4, to the blending means 5. This allows the use of fresh system oil instead or in addition to the used system oil from oil sump 2. The apparatus may also be fitted with additional piping and valves that would allow the controller 11 to replenish the system oil used or removed from oil sump 2. FIG. 2 further shows a cylinder oil tank 13 that can be used to buffer cylinder oil production and use.

EXAMPLE

(7) The following example will show the advantages of the present invention in view of the prior art for a typical example of a cylinder oil. Table 1 shows for the commercially relevant TBN values 40 to 100 the amount of system oil that must be blended with the additives or with fresh cylinder oil, respectively, to arrive at the desired TBN value. Column 3 of table 1 concerning the additives is calculated in accordance with the system known from EP 1 640 442 B1. As fresh cylinder oil, NAVIGO 100 MCL™ (available from LUKOIL Marine Lubricants Ltd., Hamburg, Germany) with a kinematic viscosity of 20 mm.sup.2/s at 100° C. and a TBN value of 100 has been used. As system oil a commercially available system oil with a TBN value of 6 and a kinematic viscosity of 11.5 mm.sup.2/s at 100° C. has been used (i.e. NAVIGO 6 SO). As additive, a commercially available additive (i.e. Chevron OLOA 49805) with a TBN value of 320 and an apparent kinematic viscosity of 39 has been used. The measured kinematic viscosity of the additives is 101 mm.sup.2/s at 100° C. However, the additives are non-Newtonian fluids and the flow properties differ from those of Newtonian fluids when diluted with oils. In mixtures with system oil, the additive behaves as if it has a kinematic viscosity of 39 mm.sup.2/s at 100° C. The later value is therefore used for the calculation of the kinematic viscosity of the resulting cylinder oil.

(8) The TBN value of the resulting cylinder oil is the weighted mean average values of the TBN values of the system oil and the fresh cylinder oil used. The values of the amount of system oil necessary to reach the desired TBN value has been calculated accordingly.

(9) TABLE-US-00001 TABLE 1 TBN values of Mixtures of system oil with fresh cylinder oil or additives Fresh cylinder oil Additives Weight percent system oil in Weight percent system oil in TBN the mixture the mixture 40 63.83% 89.17% 50 53.19% 85.99% 60 42.55% 82.80% 70 31.91% 79.62% 80 21.28% 76.43% 90 10.64% 73.25% 100 00.00% 70.06%

(10) FIG. 3 shows the same data as Table 1 as in the form of graphs, i.e. the TBN value as a function of the amount of system oil in the resulting cylinder oil. As can be seen, for any of the commercially useful TBN values, an amount of at least 70% system oil is necessary to arrive at the desired TBN value, if the cylinder oil is produced according to the prior art (Graph A). In contrast, according to the present invention (Graph B), an amount of 0% to about 64% system oil is necessary. For a MAN B&W two-stroke crosshead engine with a bore of 80 cm, when using a heavy fuel oil (HFO) with a sulfur content of 3% by weight, a cylinder oil with a TBN value of 70 and a kinematic viscosity of 17 is recommended at a feed rate of 0.6 g/kWh. For the desired TBN value of 70, about 30% cylinder oil is necessary according to the present invention and about 80% according to the prior art. For such an engine, the manufacturer recommends the continued renewal of a certain amount of system oil used in the engine in order to replenish the system oil and to remove used system oil. The use of about 30% of system oil in the cylinder oil would be in accordance with the amount of used system oil that needs to be withdrawn from the engine continuously. Therefore, the process according to the present invention uses about the same amount of used system oil that accumulates in the same time from the oil exchange in the engine. In contrast, the process, according to EP 1 640 442 B1 uses more than twice that amount, resulting in the use of system oil that is almost unused, thereby resulting in waste.

(11) As discussed, for the above-mentioned engine, a heavy fuel oil comprising 3% by weight sulfur, a TBN value of 70 and a viscosity of 17 are recommended. From the amount of system oil and fresh cylinder oil in the resulting cylinder oil and the viscosity data of the system oil and the fresh cylinder oil, the kinematic viscosity of the resulting cylinder oil can be calculated according to the equation of Ubbelohde-Walther (see DIN 51563). For the mixtures with a TBN value of 70, the viscosities are significantly lower than the recommended viscosity, namely 14.3 mm.sup.2/s at 100° C. for a mixture of system oil and additives and 16.6 mm.sup.2/s at 100° C. for a mixture of system oil with 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, i.e. 16.6 mm.sup.2/s at 100° C. as compared to the desired 17 mm.sup.2/s at 100° C. In contrast, the kinematic viscosity of the cylinder oil produced according to the prior art has a viscosity that is much lower than the target viscosity, i.e. 14.3 mm.sup.2/s at 100° C. as compared to 17 mm.sup.2/s at 100° C.

(12) As discussed 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 the piston ring may come in direct contact with the cylinder liner leading to increased wear. Furthermore, as a consequence of the low oil film thickness the alkalinity reserve of the oil film covering the liner surface is too low, as less oil comprises less base compounds per surface area (which leads to a reduced alkalinity reserve), leading to a higher level of corrosive wear. This also results in a reduced alkalinity reserve. As a consequence, the feed rate for the cylinder oil has to be higher for the cylinder oil prepared according to the prior art. The present invention therefore reduces wear, corrosion and the amount of cylinder oil used and is therefore advantageous in the operation of internal combustion engines over the prior art.

LIST OF REFERENCE NUMERALS

(13) 1 internal combustion engine 2 oil sump 3 piping 4 valve 5 blending means 6 fresh cylinder storage tank 7 piping 8 pump 9 piping 10 cylinder of internal combustion engine 11 controller 12 system oil tank 13 cylinder oil tank 14 piping