JP6239033B2 - Combustion engine - Google Patents

Description

  The present invention relates to a combustion engine, in particular a diesel engine, preferably a two-cycle large diesel engine according to the superordinate concept of claim 1 for turbocharging and exhaust gas circulation, in which the circulation line passes through gas treatment equipment. Guided.

  Especially in large diesel engines, a turbocharge stage is usually used to remove energy from the exhaust gas coming from the engine, thereby compressing the charge air to be supplied to the engine or the charge gas to be supplied to the engine and improving combustion. It is. Particularly in multi-cylinder engines, a plurality of turbochargers are used for this purpose, and these turbochargers together form a turbocharge stage.

  In addition to means such as turbocharging, which correspond to recovering energy from the exhausted combustion gas or exhaust gas, the cleanest possible combustion is currently directed. For this purpose, part of the exhaust gas is often circulated to the inlet side of the engine, thus reducing the combustion temperature and the NOx emissions of the engine.

  An example of a two-cycle large diesel engine that circulates exhaust gas or combustion gas is described in Patent Document 1 of the present applicant. Here, the circulation line is provided with a compressor of a low-pressure turbocharger, and compresses a portion of the exhaust gas to be circulated to a desired filling air pressure. This filling air pressure is the pressure on the air inlet side, that is, in the filling air collecting container or the filling air distribution pipe. The exhaust gas stream to be returned here is cooled in order to reduce the required capacity of the compressor. For this purpose, a rotary heat exchanger is provided in the circulation line, and the exhaust gas partial flow to be returned by this rotary heat exchanger is cooled by the charged air flow. The heat exchanger can also be configured as a plate heat exchanger. Here, the exhaust gas stream to be pumped back to the engine inlet side can be dried in a heat exchanger and thus humidified downstream of the rotary heat exchanger and further cooled by evaporative cooling of the absorbed water vapor. The charge air partial stream branched to cool the exhaust gas partial stream to be returned is on the one hand cooled by humidification and used to drive the compressor for the returned exhaust gas partial stream. The heat exchanger, the humidifier and the compressor thus form a gas treatment device, through which the circulation line is guided.

  Here, the temperature of the exhaust gas partial flow is surely lowered by increasing the humidity of the exhaust gas partial flow after the return. However, thermal energy can no longer be removed from the returned exhaust gas partial stream, or at least little can be removed. This is because the resulting moisture is not separated and is entrained through the compressor as vapor or aerosol particles. Therefore, the exhaust gas cleaning of the exhaust gas partial flow to be returned is not performed or sufficient cleaning is not performed even in the humidification step. This is because the sulfur particles and carbon particles contained in the exhaust gas do not reach separable condensed water, or only a very small portion reaches the condensed water. Here, the exhaust gas return certainly contributes to NOx reduction, but this increases the sulfur contamination in the exhaust gas. Furthermore, harmful substances contained in the exhaust gas that has been returned are highly invasive to the equipment used in the circulation line, and at least not only to the compressor to which the exhaust gas humidifier is connected in front. In particular, it is highly invasive to heat exchangers.

  Frequently, heavy oil is used as fuel, especially exhaust gas that is returned to the combustion chamber in large ship engines contains large amounts of sulfur and carbon, and in order to clean this, is it necessary to provide a gas scrubber in the circulation line? Or it is known to guide a circulation line through a gas scrubber.

  An example of a two-cycle large diesel engine in which exhaust gas or combustion gas is circulated and a gas scrubber is disposed upstream of the compressor in the circulation line is disclosed in Patent Document 2 (International Application No. PCT / PCT). DK93 / 00398). The gas scrubber has a plurality of water spray stages, i.e. water scrubbers, in which water is injected to wash off sulfur particles and carbon particles from the exhaust gas partial stream to be returned. The exhaust gas partial flow returned here is also cooled as a side effect in order to reduce the required capacity of the compressor. However, the exhaust gas partial flow that is returned carries most of the injected water through the compressor as vapor and aerosol cargo, so that the compressor is thereby entrained or entrained Since the pressure is increased by the partial pressure of water, it must be designed with a large rated output as usual. Here, the gas treatment device is formed by a compressor and a multi-stage water scrubber.

  Patent Document 3 (unexamined) and the corresponding US Patent Application Publication No. 2009/0107141 discloses a turbomachine having an exhaust gas recirculation system, along the recirculation line, upstream cooler, steam, acid A gas scrubber for removing aldehyde, a downstream cooler, and a wet electrostatic precipitator are arranged. In the gas scrubber, ammonia, a limestone-based liquid reagent, water, etc. are injected to perform an adsorption process that removes the above components from the exhaust stream by producing particulate matter. In removing particulate matter that comes with the exhaust stream from the gas scrubber, the wet electrostatic precipitator removes particulate matter by inducing an electrostatic charge and using a liquid to perform an action similar to cleaning. .

  Further, Patent Document 4 of the present applicant also discloses a diesel engine in which a gas cleaning device is arranged in a circulation pipe and performs exhaust gas circulation. The gas scrubber has a water jet part to the circulation line in the previous stage, thereby forming an aerosol including water particles as a water condensation core for depositing carbon particles and sulfur particles by soot. Thereafter, the circulation line is divided into a plurality of channels, each of which has an injection nozzle for injecting additional water as a cleaning liquid in a separate stage, so that separate water particles are smoke, water, and aerosol. Formed inside. Subsequently, a supersaturated mass flow in which harmful particles contained in the injected water and exhaust gas are deposited is guided downward through a washing bath, and in this washing bath, a harmful substance to which a part of the flowing water contained in the aerosol is attached. It is absorbed and discharged with the particles. Finally, the gas stream is guided upward through the bottom of the cleaning bath around the deflection edge of a deflection shield used as a water drop catcher, and the remaining water drops dripping onto this deflection shield. However, gas scrubbers are large and must be correspondingly heat resistant because of the high exhaust gas temperatures, and are therefore expensive. Again, the gas scrubber duct wall in front of the scrubbing bath is exposed to the attack of invasive harmful substances in the exhaust gas. Here, the gas processing device is formed by a gas cleaning device.

  In the improved form of circulating gas cleaning, the applicant's patent document 5 discloses a diesel engine that performs exhaust gas circulation and is turbo-filled. In this diesel engine, a gas cooler is provided with a cooler in a circulation line, and in this cooler, steam contained in the circulation gas is condensed and discharged after gas cleaning, and then the circulation gas is supplied to the intake pipe again. Is done. Due to cooling by heat dissipation from the returned exhaust gas, most of the water vapor and water aerosol particles that are always contained are condensed and deposited from the returned exhaust gas, and these are then separated into the rear liquid discharge part Can be removed from the mass flow through the circulation circuit. Therefore, on the one hand, the volumetric flow is reduced due to a decrease in the exhaust gas temperature and, on the other hand, a reduction in mass or a decrease in the partial pressure of the water condensed and taken out as aerosol particles.

  Patent Document 6 discloses a combustion engine that is charged in two stages and performs exhaust gas circulation. Here, the circulation line branches off from the exhaust gas line before the first turbocharge stage and joins the inlet air line between the two compressors. A gas cleaning device is disposed in the circulation line, and a cooler is incorporated therein.

German patent invention No. 103 31 187 WO94 / 29587 pamphlet JP 2009-108848 A German Patent Invention No. 10 2009 010 808 specification JP 2011-157959 A International Publication No. 2011-141431 Pamphlet

  Starting from here, the object of the present invention is to reduce the cost of the gas processing equipment through which the exhaust gas to be returned flows in the combustion engine of the type described at the beginning, while maintaining a good cleaning action. Is to configure.

  According to the present invention, a gas processing device has an apparatus that creates a moist environment in a section of a circulation line. This section removes heat from the returned exhaust gas and is guided, inter alia, through a cooling device operated by a coolant. Furthermore, the cooling device has at least one liquid outlet downstream in the flow direction, and a gas scrubber is downstream in the flow direction of the cooler, i.e. downstream of the cooler. This is because the advantage of heat removal in the cooled circulation line section is particularly increased. That is, the gas scrubber can be configured to be much smaller and cheaper than a gas scrubber that does not perform wet cooling beforehand, and the pressure drop can remain the same. In particular, cooling allows the use of plastic components or plastic components in the gas scrubber, thereby significantly reducing manufacturing costs and weight and forming the surface of the gas scrubber non-corrosive or almost corrosive. be able to. The additional gas scrubbing equipment in the circulation system can of course further improve the flushing of carbon and sulfur from the return exhaust gas already performed by the cooler.

  Here, particularly efficient gas cleaning is achieved by the cleaning bath. The exhaust gas to be circulated is guided through this washing bath and preferably has a pre-connected water washing nozzle. According to the present invention, the circulation pipe further extends from the cooling section to the rear gas scrubber with an inclination, so that the coolant flowing through the cooling wall in the cooling section is also moist in the gas scrubber and the corrosion protection layer. This coolant can be removed from the circulation system at the liquid outlet present anyway. Here, since there is a washing bath at the lowest point of the slope, the contaminated coolant flowing on the surface is absorbed by the washing bath and can be discharged from there when the bath is changed.

  Clean the heat exchanger or cooler by allowing the cooling to take place in a moist environment, i.e. moistening the surface cooled by the cooler or chiller with water or other suitable liquid beforehand, for example with a humidifier. Can be kept and protected from corrosion. This is because the heat exchanger or cooler is not directly exposed to invasive carbon particles or sulfur particles in the exhaust gas. These particles tend to adhere when the surface is hot and dry. This is because the surface facing the exhaust gas is always covered with a liquid film acting as a corrosion protection layer. The liquid adhering here is always exchanged with water condensed by cooling from the returned exhaust gas. Therefore, the cooler self-cleans to some extent. This is particularly important in the case of a suitable cooler, for example a heat exchanger or a fluidized bed cooler. This is because there must be a large surface when the pipe cross section is small. This makes it possible to use a cooler with particularly fine tube capillaries, which promises a large heat removal from the circulated exhaust gas. The efficiency here is further increased since the water film itself already allows an improved heat transfer to the cooled surface.

  It is advantageous here if the flow path from the cooled line section in the circulation line to the liquid outlet elapses with an inclination to carry the liquid. Further advantageously, the gas scrubber can be optimized for washing out fine particles since the coarse particles are already prewashed in the cooling section of the cooler or circulation system.

  Furthermore, it is advantageous if the gas treatment device is designed such that the circulation line or the exhaust gas stream flowing therethrough is cooled below the dew point of the water contained in the exhaust gas to be returned. Therefore, at the junction to the intake pipe, the pressure level present in the intake pipe is slightly raised, so the compressor provided there for the exhaust gas to be returned, i.e. the circulating gas compressor, is relatively modest in capacity. Can be designed. However, this makes it possible to size other devices that are connected downstream of the cooler as compared to the case where heat removal is not performed by the exhaust gas flow.

  It is particularly advantageous here for the temperature drop to allow plastic components to be integrated into the sections after the cooler and the equipment of the circulation system or circuit, which not only significantly reduces the production costs, but also the components. In addition, it is possible to obtain a surface with less tendency to adhere and corrode. Also from the viewpoint of operation reliability, it is advantageous that the temperature of the pipe section placed after the cooler is lowered to, for example, a temperature of 50 ° C to 60 ° C. The heat extracted from the circulated exhaust gas can also be used for other purposes in addition to it, for example for hot water preparation in power plants or for ships where combustion engines are used. . Along with the condensed water, carbon particles and sulfur particles adhering to the water droplets are discharged, so that a certain amount of gas cleaning is already performed only by cooling in a humid environment. This gas cleaning protects the downstream apparatus, for example, the circulating gas compressor at the junction to the intake pipe, from corrosion. Here, it should be considered that the water droplets grow larger if the sulfur or carbon to be cleaned deposits better on the water droplets. However, as the temperature decreases, the size of water particles or droplets in the aerosol increases.

  Advantageously, the device for creating a moist environment is pre-injected in the direction of flow in the section of the circulation line cooled by the cooler and injects coolant into the exhaust gas circulation line or Has a pre-injection device. By humidifying the returned exhaust gas flow in advance, a temperature drop in the returned exhaust gas is achieved. This is because sufficient liquid is jetted, the pipe wall is moistened by the jetted water, and water condensation from the exhaust gas is achieved. Of course, a plurality of pre-injection stages can also be provided. Further, in addition to the pre-injection unit or the front nozzle device, it is also possible to inject water into the flowing gas flow by the cooler itself or in the cooling section of the circulation line.

  As an alternative or supplement, a cold water supply can be provided which is led to a cooling device or cooler. This cold water supply wets or wets the surface facing the exhaust gas in the cooling section of the circulation line via a suitable water distributor.

  Either the area preceding the cooling section of the circulation line, or the cooling area itself of the circulation line, instead of or replenishing the water stream or other aqueous liquid (eg salt water) into a gas stream by atomization In particular, it is also advantageous to direct a water stream to the surface of the circulation line exposed to the exhaust gas and create a wet and moist environment with the resulting corrosion protection layer. If such water injection is performed in the region of the circulation line preceding the cooling section, it is advantageous if the circulation line has an inclination to the cooling section, so that the injected water is It flows to the section to be cooled along the pipe wall.

  The cooler suitable for the cooling device provided by the present invention can be a wet bed cooler, which has, for example, its own cold water supply and an injection device or sprinkler device connected to it, and a circulation pipe A wet surface film is formed on or wetted on the surface of the cooling section of the passage facing the exhaust gas to be circulated. For this purpose, the wet bed cooler preferably has a large surface or an enlarged surface relative to a simple pipe line, this surface being, for example, a grid, a sieve, a flowing plate or rib, or a flowing solid It is attached to the circulation line there in the form of a solid which is always wetted with liquid via a sprinkler device. A fluid bed that cools and wets the gas stream in this way is obtained from the coolant flowing over the surface. Therefore, heat removal from the returned exhaust gas takes place through the flowing wet fluidized bed. As an alternative or in addition to the cooler's own cold water supply, if it is guaranteed that the cooler surface is always wet, it will be pre-filled in the area of the circulation line that precedes the cooler. An injection device can be provided.

  As an alternative to or in addition to the wet bed cooler, the gas treatment device preferably also has a regenerative heat exchanger that operates with water or other suitable aqueous fluid, for example seawater as the coolant. As a result, the exhaust gas returned or the pipe wall of the circulation pipe can be cooled. Here, the regenerative heat exchanger can directly cool the surface of the circulation line through which the exhaust gas to be returned flows in the cooling section, or indirectly by using, for example, seawater as a primary cooling liquid, The circulation line through which the exhaust gas flows is cooled again in the cooling section by the secondary cooling liquid, for example, pure water.

  Heat is extracted from the returned exhaust gas with the highest efficiency by cooling with a regenerative heat exchanger operating with water as a cooling medium. Additional to sprinkle on the enlarged surface on the side facing the exhaust gas in the regenerative heat exchanger (eg in the form of cooling ribs around the pipe bundle in the cooling section of the circulation line and through which the coolant flows) With a simple sprinkler device, the cooling capacity can be further improved.

  However, it is equally conceivable to use an indirect cooler, for example an adiabatic cooler. The adiabatic cooler discharges evaporative cooling generated in the other gas flow to the regenerative heat exchanger or the fluidized bed cooler on the circulation line side with water as a coolant. For this purpose, other gas streams can be used, for example air streams coming from the environment, non-returned exhaust gas that exits the environment at the end of the exhaust pipe, or filled air supplied to the combustion engine inlet Water can be injected into this gas stream to form evaporative cooling. Furthermore, on the side that is not suitable for the exhaust gas, it is conceivable that the coolant flow is not passed through the wall of the circulation pipe, and the coolant evaporates there, and the amount of coolant that causes the corresponding evaporative cooling is simply sprinkled. .

  In order to further enhance the exhaust gas drying effect achieved paradoxically by cooling in a humid environment, a water drop remover can be provided after the cooling section in the direction of flow. Advantageously, if present, the gas scrubber is also followed by a water drop remover. Despite the need for contact between the returned exhaust gas flow and the cleaning liquid (water) for gas cleaning in the gas cleaning equipment, the exhaust gas flow is saturated when the temperature of the cooled exhaust gas is low This is because water vapor cannot be absorbed due to the small limit, or a large amount of water vapor cannot be absorbed, but in some cases, a larger number of aerosol particles can be entrained in a supersaturated state. These water drops can then be removed from the volumetric stream flowing through the circulation circuit with a water drop remover on the outlet side and discharged from a suitable water condensation outlet. This further reduces the mass flow to be raised to the pressure level in the intake pipe at the junction to the intake pipe. The use of deflector plates, solid bodies, sieves, and perforated plates as a water drop remover has proven effective, and these can be made of plastic because of the exhaust gas cooling.

  In order to further improve the desired drying and cleaning action, the gas processing equipment can also be configured in multiple stages.

  In order to further improve the space savings achieved by cooling when sizing the gas scrubber equipment, at least the gas scrubber equipment and the cooler, preferably other elements of the gas treatment equipment, or all other elements Can be integrated into one overall device with a common housing.

  In the following, preferred embodiments of the present invention will be described with reference to the schematic drawings.

1 is a schematic view of a combustion engine according to a first embodiment of the present invention. FIG. 3 is a schematic view of a combustion engine according to another embodiment of the present invention. FIG. 3 is a schematic diagram of a gas processing device for a combustion engine according to another embodiment of the present invention. FIG. 3 is a schematic diagram of a gas processing device for a combustion engine according to another embodiment of the present invention. FIG. 3 is a schematic diagram of a gas processing device for a combustion engine according to another embodiment of the present invention. FIG. 3 is a schematic diagram of a gas processing device for a combustion engine according to another embodiment of the present invention. FIG. 3 is a schematic diagram of a gas processing device for a combustion engine according to another embodiment of the present invention. FIG. 3 is a schematic diagram of a gas processing device for a combustion engine according to another embodiment of the present invention. FIG. 3 is a schematic diagram of a gas processing device for a combustion engine according to another embodiment of the present invention.

  The main field of application of the invention is large engines, especially two-cycle large diesel engines that can be used as ship drives or in power plants. The structure and operation of this type of engine is known per se.

  FIG. 1 schematically shows a two-cycle large diesel engine that can have an in-line cylinder Z. Each cylinder Z restricts the combustion chamber B by the piston K which cooperates. One exhaust valve A is provided at the upper end of each combustion chamber B, and exhaust gas generated during combustion is discharged to the exhaust gas collection container 15 through this exhaust valve. From there, the exhaust gas reaches the turbine 18 of the turbocharger 1 through one (or more) exhaust line 23. However, part of the exhaust gas is fed back from the circulation line 3 branched from the exhaust line 12 to the inlet side of the combustion engine or the intake pipe. The circulation line can be branched from the exhaust pipe already upstream of the exhaust gas collection container 15 or can be branched by a unique outlet already in the combustion chamber B. The intake pipe has a compressor 19 of the turbocharger 1 on the inlet side, and this compressor is driven by the exhaust gas guided through the turbine 18 to raise the supplied charge air to a high pressure level. From the compressor 19, a filling air line 11 leads to a filling air collecting container 14 or a filling air collecting line 14 via an optional filling air cooler 13, from which the individual combustion chambers B Fresh air is sent to The exhaust gas circulation line 3 joins the filled air line 11 in front of the filled air accumulator 14. That is, they merge at the front or rear of the filled air cooler 13. Here, the circulation pipe 3 is supplied to a gas processing device indicated by a broken line and indicated by 2.

  The gas processing device 2 has a pre-injection device 5 on the inlet side. That is, it has one or a plurality of nozzles provided in the circulation line 3, and cold water coming from the liquid supply unit 4 is sent to the nozzles, and this cold water is injected into the circulation line 3, thereby the circulation pipe A moist environment is created in the path 3, especially in the region of the circulation line 3 that is placed after the pre-injection device 5. This region is led through the regenerative heat exchanger 6 and is thereby cooled.

  Therefore, there is a moist environment on the exhaust gas side of the regenerative heat exchanger 6, and this moist environment is in a liquid state on the outer wall of the heat exchanger 6 against carbon adhesion and chemical invasion of sulfur particles contained in the exhaust gas. A corrosion protection protective layer is formed. On the coolant side, chilled water flows through the regenerative heat exchanger, which in most cases can be advantageously prepared and has a high heat transfer capacity. When using a combustion engine for a ship, sending seawater to the heat exchanger 6 is also considered. The liquid jetted to the circulation pipe 3 by the pre-injection device 5 flows along the pipe wall into the region of the circulation pipe 3 that is cooled by the heat exchanger 6. This is because the heat exchanger 6 exists below the pre-injection device 5 in the gravity line. In other words, the circulation line 3 has an inclination from the pre-injection device 5 through the heat exchanger 6.

  There is a gas cleaning device 7 in the region of the circulation line 3 placed behind the regenerative heat exchanger 6 in the flow direction, and the circulation line 3 is guided through this gas cleaning device. The gas cleaning device 7 is located below the regenerative heat exchanger 6, so that the coolant that is injected into the circulation line 3 by the pre-injection device 5 and flows through the heat exchanger 6, and the exhaust gas by cooling in the heat exchanger 6. The liquid condensed from the flow flows into the gas scrubber 7. Here, the cooling of the heat exchanger 6 and the condensation of water vapor that is always contained in the exhaust gas associated therewith (the exhaust gas contains 25% by mass of water in the case of a large diesel engine) Cleaning is performed. This is because carbon particles and sulfur particles contained in the exhaust gas adhere better to the formed condensation nuclei as the water droplets become larger, and are therefore absorbed in the liquid phase. Here, the gas cleaning device 7 can be provided with an overflow bath to which water as a cleaning liquid is continuously sent, and the gas stream previously dried and pre-cleaned by the cooler 6 is guided through this overflow bath. In the cleaning bath, fine dust particles still contained in the exhaust gas are absorbed and separated by overflow with the contaminated cleaning liquid. Here, the gas cleaning device 7 can have a specific cleaning liquid supply section as indicated by a broken line. However, since the cleaning liquid sprayed by the pre-injection device 5 flows into the cleaning bath, it is sufficient to send the pre-sprayed cleaning liquid. Furthermore, one or a plurality of water washing stages can be pre-connected to the washing bath, in which further washing liquid, ie pure water or salt water, is injected into the circulation line 3.

  A water droplet separator can be optionally provided further downstream of the circulation line 3. That is, for example, various deflecting plates can be provided in the exhaust gas flow path, or corresponding solid bodies can be provided, thereby separating the water droplets still contained in the cold exhaust gas flow, thereby reducing the exhaust gas flow. Further drying and final cleaning can be performed.

  There is also a liquid outlet or liquid outlet line 8, in which a discharge pump can optionally be arranged if it is likewise not guided with an inclination.

  The cooled, dried and purified exhaust gas stream is fed to the compressor 10. This compressor is at the end of the circulation line 3 and raises the circulated exhaust gas to a pressure level in the inlet line 11 so that the exhaust gas can be circulated into the combustion chamber B together with freshly charged air. . By removing the water vapor initially contained in the circulated exhaust gas, the gas volume flow to be conveyed becomes relatively small, and therefore the compressor 10 can also be designed to be relatively small. In particular by radical exhaust gas cleaning, the compressor 10 is further exposed to much less erosion than in the case of known devices of this type and therefore has a longer life. This has a great advantage on the operating costs of the combustion engine. This is because the compressor 10 is relatively expensive. Due to the cooling of the returned exhaust gas stream (exhaust gas existing at 400 ° C., for example, by wet cooling can be cooled to a value of 100 ° C. or lower, and in part, 50 ° C. or lower), exhaust gas cleaning A number of plastic housing members and conduit members can be used in the device 7, as is the compressor 10. Here, the gas cleaning device 7 can also be sized significantly smaller than a combustion engine that does not cool the exhaust gas that is circulated, which increases the pressure loss in the exhaust gas cleaning device 7. There is no. For reasons of space saving and simple installation, the individual devices of the gas treatment device 2 can be integrated into one common gas treatment device, preferably in one common housing.

  FIG. 2 shows a combustion engine that is substantially different from the combustion engine shown in FIG. 1 in that the circulation line 103 exists on the low pressure side of the turbocharger 1. Accordingly, the same or functionally identical components are provided with the same reference numerals as in FIG. 1, and different reference numerals are used only for the gas processing equipment 102 in the circulation system.

  However, the principle of wet cooling the returned exhaust gas to dry the exhaust gas stream and clean the carbon and sulfur particles is the same. In the pre-injection device 105, water from the supply unit 104 is injected into the circulation pipe 103, and flows to the regenerative heat exchanger 106 along the pipe wall along a fall line. The regenerative heat exchanger operates with water as a coolant and operates in a humid environment on the side facing the exhaust gas. That is, it is moistened with water sprayed by the pre-injection device 105. Subsequently, in the gas cleaning device 107, the exhaust gas that has already been pre-cleaned by condensation in the cooler 106 is subjected to final cleaning, followed by final drying of the exhaust gas in the water droplet remover 109, and the cleaning liquid and cooling liquid are circulated in the exhaust gas. It is discharged from the conduit 3 through the outlet 108. Next, the returned exhaust gas flow reaches the compressor 104, and the returned exhaust gas flow is sucked by the compressor from the low pressure side of the exhaust pipe to the low pressure side of the intake pipe.

  FIGS. 3-9 show alternative gas treatment equipment 2 and 102 according to another embodiment of the present invention.

  The only difference between the gas treatment device shown in FIG. 3 and the gas treatment device 2 shown in FIG. 1 is that the additional gas cleaning device 7 is omitted here. This is because sufficient exhaust gas scrubbing can already be achieved for many applications by only sufficient cooling in a humid environment. The pre-injection device 5, again the regenerative heat exchanger 6 used as a cooler 6, and the water drop remover 9, which is provided behind this regenerative heat exchanger in the flow direction and is provided with a liquid outlet 8, is again a compressor The same reference numerals as those in FIG.

  In contrast, FIG. 4 shows an embodiment of a gas processing device provided with a fluidized bed cooler 16. In this fluidized bed cooler, a large surface such as a cooling rib is provided on the side facing the exhaust gas, and this surface is moistened by the coolant directly guided to the cooler 16 via the coolant supply unit 17. The The coolant then flows down from the fluid bed cooler 16 in the direction of the liquid outlet 8 along a drop line or slope. A water drop remover 9 can be further connected to the liquid outlet. Thus, the returned exhaust gas first reaches the fluidized bed cooler 16 where it comes into contact with a large wet and cold surface. This cools and under heat removal, the coagulated water on which the carbon particles and gas particles are deposited is precipitated. The carbon particles and gas particles are discharged from the circulation line at the liquid outlet 8 together with the liquid phase. The dried, cooled, and cleaned exhaust gas then passes through the water drop remover 9 and then flows through the circulation line to the compressor 10 where it is pumped to the intake pipe of the combustion engine. As an option, a flow cooler 19 is arranged at the inlet 17, which is here configured as a regenerative heat exchanger 19 that operates with water as the coolant. Therefore, the coolant supplied to the fluidized bed cooler or wet bed cooler 16 is a secondary coolant. Here, for example, fresh water can be used, and seawater can be used as the primary coolant in the flow cooler 19. Therefore, the contained salt does not reach the exhaust gas circulation line. Here, the flow cooler 19 can be part of an adiabatic cooling system. This adiabatic cooling system uses the cooling prepared here as evaporative cooling, removes it from another air flow or gas flow as an exhaust gas flow, and in the case where a liquid to be evaporated is injected into the filling air cooler 13, for example, filling The air stream is removed with a filled air cooler 13.

  Another variation suitable as a substitute for the gas treatment equipment 2 or 102 is shown in FIG. The modification shown in FIG. 5 corresponds to the modification of the gas processing apparatus shown in FIG. 4. Here, the pre-injection device 5 is further connected in front of the wet bed cooler 16 in the flow direction. Yes. In this pre-injection device, additional water is injected into the circulation line, and then the exhaust gas reaches the cooler 16.

  FIG. 6 shows a modified form of the gas processing apparatus that is expanded in that the gas cleaning apparatus 7 is placed behind the wet bed cooler 16 with respect to the modified form of the gas processing apparatus shown in FIG. Accordingly, the gas processing device shown in FIG. 6 corresponds to the gas processing device shown in FIG. 1, but here, the wet bed cooler 16 is used as a cooling device instead of the regenerative heat exchanger. The wet bed cooler 16 has an inherent liquid supply 17 as a mere option as shown by the broken line. The liquid supply unit can be supplementarily provided in the pre-injection device 5 when the moisture provided through the pre-injection device 5 is not sufficient, and thereby the surface of the cooling section of the circulation line can be sufficiently provided by the liquid. Can be moistened. This also applies to the embodiment of FIGS. 5 and 7 where the liquid supply 17 of the wet bed cooler is also optional, as is the liquid supply to the gas scrubber 7 shown in FIG. . The gas scrubber 7 can also be driven solely by the condensed water flowing into the gas scrubber 7 and the cooling and cleaning liquid supplied at 4 and 17.

  FIG. 7 shows a modification of the gas processing apparatus, which is expanded by the amount of the water droplet remover 9a between the wet bed cooler 16 and the gas scrubber 7 placed behind the wet bed cooler 16. In the additional water drop remover 9 a, the gas mass flow or aerosol mass flow is dried, entrained particles are removed, and then the mass flow is directed to the gas scrubber 7. The water drop remover 9a is provided with a liquid outlet 8a, in which pre-cleaning during pre-injection in the pre-injection device 5, heat removal and condensation in the cooler 16 associated therewith, and subsequent water drop remover By removing the water droplets at 9a, the contaminated cleaning liquid or cooling liquid is discharged from the circulation line, and then the gas stream reaches the gas scrubber 7. The gas cleaning device 7 can then be supplied with fresh water as a cleaning liquid, so that the cleaning power of non-contaminated water can be demonstrated with improved exhaust gas decontamination. As is known, the gas scrubber 7 can further be provided with a water drop remover 9 b with a liquid outlet 8 b, from which the exhaust gas stream returned to the compressor 10. If the flow rate in the gas cleaning device 7 is sufficiently slow, the post-droplet remover 9b can be omitted.

  FIG. 8 shows a modification of the gas processing device corresponding to FIG. Here, an additional preprocessing stage is pre-connected to the known gas processing equipment from FIG.

  The pre-treatment stage is provided with a water injection device 25 on the inlet side for finely subdividing water into the preheated gas stream, so that for the first time water condensation nuclei are formed in the gas stream. Carbon particles and other harmful substance particles can be deposited on the water condensation core. A subsequent water drop remover 19 removes these contaminated water drops from the gas stream. Thus, the gas stream that has already been pre-cleaned reaches the main part of the gas treatment device previously described with reference to FIG.

  FIG. 9 also shows a multi-stage gas processing device. This gas processing device has a main stage 32 corresponding to the gas processing device shown in FIG. 7, and a preprocessing stage 22 is connected in front of the main processing stage 32. This preprocessing stage corresponds to the structure of the gas processing equipment of FIG. 5, but the compressor 10 is not intermediately connected between the preprocessing stage 22 and the main processing stage 32.

  Changes and modifications to the illustrated embodiments are possible without departing from the scope of the present invention.

  It is also conceivable to install a steam generator in front of another device in the gas processing stage, for example, in a circulation line and use the heat contained in the circulated exhaust gas for steam generation. And this steam can drive the steam turbine which forms an electric current, for example for onboard power supplies, such as a ship.

DESCRIPTION OF SYMBOLS 1 Turbocharger 2 Gas processing apparatus 3 Circulation line 4 Liquid supply part 5 Pre-injection apparatus 6 Heat exchanger 7 Gas washing apparatus 8 Liquid outlet 9 Water drop remover 10 Compressor 11 Filling air line 12 Exhaust line 13 Filling air cooler 14 Filled air collection container 15 Exhaust gas collection container 16 Cooler 17 Liquid supply unit 18 Turbine 19 Compressor 23 Exhaust pipe 25 Water injection device 102 Gas treatment device 103 Circulation line 104 Supply unit 105 Pre-injection device 106 Regenerative heat exchanger 107 Gas cleaning device 108 Exit 109 Water drop remover

Claims (15)

A combustion engine, the combustion engine comprising:
Combustion chamber (B) limited by a cylinder and a piston that cooperates with a crankshaft, formed between a valve body of an exhaust valve (A) and an assigned valve seat, and an exhaust pipe (12 15) at least one outlet for discharging exhaust gas and at least one inlet for supplying cleaning gas from the intake pipe (11, 13, 14), which can be controlled by the piston (K). At least one combustion chamber (B) comprising:
At least one turbocharger (1) comprising a compressor in the intake pipe (11, 13, 14) and a turbine in the exhaust pipe (12, 15);
The exhaust pipe (12, 15) or the combustion chamber (B) branches to the intake pipe (11, 13, 14), and the exhaust gas partial flow is circulated to the intake pipe (11, 13, 14). A circulation line (3; 103) guided through a gas treatment device (2; 102),
The gas processing equipment (2; 102)
A device (5; 105; 17; 5, 17) for creating a moist environment in the cooling section of the circulation line (3; 103);
At least one gas scrubber (7; 107);
And at least one liquid outlet (8; 108; 8a, 8b) placed downstream in the flow direction in the cooling device (6; 106; 16, 26),
In the combustion engine, the cooling section removes heat from the returned exhaust gas and is guided through a cooling device (6; 106; 16, 26) operated by a coolant.
The gas cleaning device (7; 107) has at least one cleaning bath through which circulating exhaust gas flows, and is disposed downstream of the cooling section of the circulation pipe (3; 103), and the circulation Combustion engine characterized in that the pipe line (3; 103) is guided with an inclination from the cooling section to a gas cleaning device (7; 107) placed downstream.   2. Combustion engine according to claim 1, characterized in that the gas scrubber (7; 107) has at least one water scrubber stage connected in front.   The device (5; 105; 5, 17) for creating the moist environment is placed in front of the cooling section of the circulation line (3; 103) in the direction of flow, and the circulation line (3 103) a pre-injection device (5; 105) for moistening the surface of the cooling section facing the exhaust gas returned to the exhaust gas with the coolant, 3) The combustion engine according to claim 1 or 2, characterized in that there is an inclination in a section from the pre-injection device (5; 105) to the cooling section.   The device (17; 5, 17) for creating the moist environment has a coolant supply unit (17) that merges with the cooling device (16), and the coolant supply unit is connected to the cooling section. The combustion engine according to any one of claims 1 to 3, further comprising a coolant distributor for moistening the surface on the side facing the exhaust gas to be returned with coolant.   Combustion according to any one of the preceding claims, characterized in that the cooling device (6; 106; 16, 26) comprises at least one regenerative heat exchanger (6; 106; 26). organ. The cooling device (16, 26) has at least one wet bed cooler (16), which is wetted by the coolant on the side facing the exhaust gas to be returned and therefore has a large cooled surface. For example in the form of a grid, sieve, plate, rib, solid and / or diameter-changing part arranged in the circulation line (3; 103),
The combustion engine according to any one of claims 1 to 5, further comprising a liquid supply section (17) that joins the wet bed cooler (16) via a coolant distributor.   The gas treatment device (2; 102) has at least one water drop remover (9; 109; 9a, 9b) downstream of the cooling section, and at least one water drop remover (9; 109; 9b) The combustion engine according to any one of claims 1 to 6, wherein the combustion engine is provided downstream of the gas cleaning device (7; 107). The gas treatment device has a plurality of gas treatment stages (22, 32), each of the gas treatment stages being at least one inlet side pre-injection device for moistening the surface facing the returned exhaust gas (5) and at least one cooling device (16, 26) for removing heat from the returned exhaust gas,
Any one of the gas treatment stages can have at least one gas cleaning device according to claim 2 and / or a water drop remover according to claim 7. A combustion engine according to claim 1.   9. The at least one gas cleaning device (7; 107) and the cooling device (6; 106) are also integrated in one overall device (2; 102) having a common housing. The combustion engine according to any one of the above.   The combustion engine according to claim 9, wherein the cooling device cools a pipe wall of the gas cleaning device.   The gas scrubbing device (7; 107) is directly connected to the cooling device (6; 106; 16) by a return exhaust gas flow path, or is connected to the cooling device via an intermediately connected water droplet remover. 11. The apparatus according to any one of claims 2 to 10, characterized in that the gas cleaning device (7; 107) is followed by another water drop remover (9b) in the flow direction. Combustion engine.   The combustion engine according to any one of claims 5 to 11, characterized in that at least a part of the gas scrubbing device (7; 107) is made of a plastic component.   The branch line on the exhaust pipe side of the circulation pipe (3) and the merging section on the intake pipe side are on the high pressure side of the turbocharger (1), and the gas treatment device (2) is a circulation gas compressor. The combustion engine according to any one of claims 1 to 12, characterized in that (10) is provided at an end of the circulation line (3).   14. Combustion according to any one of the preceding claims, characterized in that the exhaust gas circulation line (3) has an inclination in the region of the gas treatment device (2) at least to the liquid outlet (8). organ. The gas processing device has a steam generator upstream of the cooling device and upstream of the pre-injection device, according to any one of claims 4 to 14, when citing claim 3. Or the combustion engine of Claim 3 .

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