METHOD OF TREATING OIL FOR INTERNAL COMBUSTION ENGINES AND APPARATUS USABLE FOR CARRYING OUT THE METHOD

Abstract: Method of treating oil in a system comprising a store tank, a separator and an internal combustion engine. According to the novel method a heat exchanger is used for heating the oil from the store tank, the heat exchange being regenerative. The invention also relates to a heat exchanger usable for carrying out the method.

Description: Method of treating oil for internal combustion engines and apparatus usable for carrying out the method. This invention relates to a method of treating oil for an internal combustion engine preferably on a ship, oil from a store tank being conducted in a conduit via a heater to a sepa¬ rator where it is cleaned before it reaches the engine via a collecting tank. The invention also comprises an apparatus usable for carrying out the method. The combustion oils for engines on ships for instance have very low quality for reasons of expense. Therefore, the oil has to be cleaned in a separator before it reaches the internal combustion engine. In the separator, the temperature of the oil has to be about 100°C if the separation process shall be able to func¬ tion. According to the stand point .of technics the oil is stored in a store tank on the ship for instance, in which tank the tempera- ture is about 50°C and from which the oil is conducted to a separator. Thus, before the oil reaches the separator it has to be heated up to about 100°C and this occurs in a heater usually by means of electricity or steam. The oil runs from the heater to the separator where the pollutions are separated' from the oil, which is accordingly cleaned there. From the separator the oil runs to a collecting tank, wherefrom oil is conducted to an internal combustion engine. The heating of the oil in the heater is very expensive and, therefore, there is a strong wish to reduce the heating cost. Furthermore, nowadays demands are put forward that the oil, that shall be stored in the collecting tank on the ship for instance, for security reasons must not hold a temperature that is higher than the flash-point (60°C) of the oil minus 10°C, i.e. ftRE l OMPI about 50°C. Thus, the hundred-degrees centigrade-oil leaving the separator has to be cooled down to about 50°C for storage in the collecting tank. This cooling down means a further expen¬ sive step in the treatment of the oil, since the oil temperature shall be reduced in the cooler from about 100°C to about 50°C. This invention is intended to reduce the cost for heating the oil in advance of the separator and for cooling down the oil after the separator. This is made possible by a method of the kind mentioned by way of introduction, which method is charac¬ terized in that a heat exchanger for regenerative heat exchange is placed in the conduit between the store tank and the heater. The invention also relates to a novel heat exchanger of plate- type which is usable for carrying out the mentioned method. A preferred embodiment of the invention shall be described more closely in connection to the accompanying drawings, in which * Fig. 1 shows a schematic sketch over the different steps when treating oil for internal combustion engines according to the novel system, Fig. 2 shows an embodiment of a plate heat exchanger usable in the system according to Fig. 1, Fig. 3 shows a view from the front of a frame plate of the heat exchanger according to Fig. 2, Fig. 4 shows another embodiment of a plate heat exchanger usable in the system according to Fig. 1, and Fig. 5 shows a view from the front of a frame plate of the heat exchanger according to Fig. 4. In Fig. 1 the novel system is shown which principally differs from the known system described in the introductory part of the specification in that way that a heat exchanger for regenerative heat exchange is introduced into the system for heating oil from the store tank. Thus, the system comprises a store tank 11, a heat exchanger 12, a heater 13, a separator 14, a cooler 15, a collecting tank 16, and an internal combustion engine 17. The heated medium of the heat exchanger 12 is oil from the store tank 11, while the heating medium of the heat exchanger is the warm oil leaving the separator 14. Due to the heat exchange in the heat exchanger, the oil from the store tank is heated up and if it does not reach the temperature of about 100°C, it is heated further in a heater by means of electricity or steam. For this reason the heating cost for the oil is essentially reduced. Furthermore, the oil intended to be conducted from the separator to the collecting tank is cooled down. This is of great impor¬ tance, because thanks to that the cooler, that is placed in advance of the collecting tank and intended to secure a tempera¬ ture of the oil not exceeding 50°C, can have smaller dimen- sions. For this reason also the cost for cooling the oil is reduced. The described system for treating the oil for the internal com¬ bustion engine must now and then be overhauled, the oil in the system congealing as a rule. This has the consequence that the heat exchanger must be designed in a special way so that the oil can stream through it when the system is taken into operation again after a service- or operation-stop. In Fig. 2 there is shown a plate heat exchanger which is desig¬ ned in that way that the exchanger is possible to use in a system where the oil periodically congeals. The heat exchanger 20 as usual comprises a frame plate 21, a number of heat exchanger plates 22 and a pressure plate 23. The purpose of the heat exchanger is to exchange heat between the oils I and II. The two heat exchanger plates 22A, B closest to the frame plate form a channel 24 into which a particular medium shall be introduced for heating up the oils I and II, which, as a rule, congeal during the service periods of the heat exchanger. Preferably, the heat exchanger plates 22A, B have a design similar to that of the remaining plates 22. This medium is suitably steam that is introduced into the channel 24 between the plates 22A and 22B via a conduit 25 going through the frame plate 21 and having connection to the plate 22A. The steam that is introduced into the channel heats up the space in it and this heat is spread to the remaining channels by the metallic contact between the plates 22, the heated oil in the adjacent channel contributing to transfer the heat. In cer¬ tain cases when the heat exchanger contains many plates and accordingly many channels for the heat exchanging media it can be suitable to arrange a channel with the same function as the channel 24 at the other end of the heat exchanger, i.e. close to the pressure place 23. When the steam from the conduit 25 comes into the channel 24 it emits heat and is transformed into condensate that Is taken out of the channel via a conduit 26 which is also connected to the plate 22A and extends through the frame plate 21. Due to the fact that the heat from the channel 24 and possibly a channel at the pressure plate 23 is spread to the remaining channels of the heat exchanger, oil in these ones possibly con- gealed is rapidly heated up, whereby the heat exchanger begins to function rapidly after a service- or operation break. A frame plate, as a rule, comprises four holes (so called ports) 31, 32, 33, 34 (see Fig. 3) for connection to the two media that shall exchange heat with each other. In this connection each medium is taken into the heat exchanger via its own hole in the frame plate and out of the heat exchanger via its own of another hole. This means that the connections to the steam channel 24 must be made via two separate ports 35, 36 in the frame plate. Due to that fact two additional holes have to be drilled in the frame plate. Moreover, two holes must be made in the plate 22A for the conduits 25, 26. These additional drillings, of course, mean increased expenses when manufacturing the heat exchanger. The costs for arranging the steam channel, however, can be re¬ duced if a pressure plate is used which in conformity with the frame plate is provided with four connections. In such a case a steam channel can be arranged in each end of the heat exchanger, two of the connections in each of the frame plate and the pres¬ sure plate being used for introducing steam and taking out the condensate, respectively. This is illustrated in Figs. 4 and 5. Oil I and steam for a channel 42 is introduced and taken out, respectively, through the frame plate 41, while oil II and steam for another channel 43 is taken in and out, respectively, through the pressure plate 44. In Fig. 5 there is shown a view from the. front of the frame plate. In this figure there are shown openings 51, 54 for intro¬ ducing and taking out, respectively, oil I and openings 52, 53 for introducing steam and taking out condensate, respectively. Instead of introducing and taking out, respectively, oil I via the frame plate it is possible to introduce oil I via the frame plate and take it out via the pressure plate. In such a case it is suitable to introduce the oil II via the pressure plate and take it out via the frame plate, whereby counterflow-effect Is obtained. .OMPI ^ ^ ^ wiPoT It is not necessary to arrange the steam channel at the end of the heat exchanger but it can be arranged at the middle of the heat exchanger for Instance. Due to that fact that advantage can be obtained that the heat is spread in the two directions. In such a case steam is suitably taken in and condensate out at the side of the heat exchanger. The heat exchanger according to the Invention Is usable when heat exchanging not only oil but also other media which have high viscosity and accordingly congeal at room temperature. A

Claims: Claims 1. Method of treating oil for an internal combustion engine preferably on a ship, oil from a store tank being conducted in a conduit via a heater to a separator where It is cleaned before it reaches the engine via a collecting tank, c h a r a c ¬ t e r i z e d i n that a heat exchanger (12) for regenera¬ tive heat exchange is placed in the conduit between the store tank (11) and the heater (13). 2. Method according to claim 1, c h a r a c t e r i z e d i n that the heated medium in the heat exchanger (12) is oil from the store tank (11), while the heating medium is oil from the separator (14). 3. Method according to claim 1 or 2, c h a r a c t e r ¬ i z e d i n that the heat exchanger (12) is a plate heat exchanger (20). 4. Apparatus comprising a plate heat exchanger for exchange of heat between two media of different temperatures, c h a ¬ r a c t e r i z e d i n that the plate heat exchanger (20) comprises a number of heat exchanger plates (22) of which at least two (22A, B) form a channel (24) for a medium that is separated from the two above-mentioned media. 5. Apparatus according to claim 4, the heat exchanger compris¬ ing a frame plate and a pressure plate, c h a r a c t e r ¬ i z e d i n that the two plates (22A, B) are placed closest to the frame plate (21). 6. Apparatus according to claim 4 or 5, c h a r a c t e r ¬ i z e d i n that a conduit (25) is connected to the plate (22A) and brings the medium into the channel (24), and that another conduit (26) is also connected to the plate (22A) and takes the medium from the channel (24). 7. Apparatus according to claim 6, c h a r a c t e r ¬ i z e d I n that the conduits (25, 26) extend through the frame plate (21). 8. Apparatus according to anyone of the claims 5-7, at least the frame plate being provided with four ports for introducing and taking out, respectively, the two media that shall exchange heat with each other, c h a r a c t e r i z e d i n that the frame plate (21) comprises two further ports (35, 36) for introducing and taking out, respectively, the medium to the channel (24). 9. Apparatus according to anyone of the claims 5-7, both the frame plate and the pressure plate having four ports, c h a — r a c t e r i z e d i n that a channel (42, 43) for recep¬ tion of the medium that is separated from the media which exchange heat with each other is placed closest to the frame plate (41) and the pressure plate (44), respectively, and that the ordinary ports of the frame plate (41) and the pressure plate (44) are used for introducing and taking out, respec¬ tively, the mentioned medium. 10. Apparatus according to anyone of the claims 4-9, c a ¬ r a c t e r i z e d i n that the medium that is introduced into the channels (24; 42, 43) is steam. OMPI < WIPO

Inventors: ANDERSSON JARL, LARSSON LEIF, ANDERSSON, JARL, LARSSON, LEIF
Applicants: ALFA LAVAL MARINE POWER ENG, ALFA-LAVAL MARINE & POWER ENGINEERING AB
Application year: 1984
Main classification: F02M31
IPC codes: F02M31, F02M37, F28D9