Large two-stroke uniflow scavenging supercharged closed-loop oxygen fuel internal combustion engine

Abstract

A large two-stroke uniflow scavenging internal combustion engine includes: a plurality of cylinders including combustion chambers; an intake system including a scavenging gas receiver connected to the cylinder to supply scavenging gas to a combustion chamber in the cylinder; a fuel system configured to supply a carbon-based fuel to the combustion chamber; comprising an exhaust gas receiver coupled to the combustion chamber via an exhaust valve, where the engine is a closed loop oxyfuel engine and comprises: a recirculation conduit connecting the exhaust gas receiver to a scavenging gas receiver; a blower located in the recirculation duct; a constructed oxygen supply system; and a separation and carbon dioxide liquefaction system wherein a portion of the exhaust stream generated in the combustion chamber is diverted to the separation and carbon dioxide liquefaction system, the separation and carbon dioxide liquefaction system being configured to separate oxygen from the diverted exhaust stream by liquefying carbon dioxide from the diverted exhaust stream.

Description

Technical Field

[0001] The present invention relates to a large two-stroke internal combustion engine, in particular to a large two-stroke uniflow scavenged supercharged closed-loop oxygen fuel internal combustion engine provided with a CO2 capture system. Background Art

[0002] Large two-stroke uniflow scavenged turbocharged crosshead internal combustion engines are commonly used in propulsion systems of large ships or as prime movers in power plants. The huge size, weight and power output make large two-stroke uniflow scavenged turbocharged crosshead internal combustion engines completely different from ordinary internal combustion engines and put large two-stroke turbocharged compression ignition internal combustion engines in a class of their own.

[0003] These large two-stroke single-flow scavenged turbocharged crosshead internal combustion engines used to operate mainly with hydrocarbon fuels, such as fuel oil, such as diesel, or fuel gas, such as natural gas or petroleum gas. The combustion of hydrocarbon fuels releases carbon dioxide (CO2) and other greenhouse gases that cause atmospheric pollution and climate change. Unlike fossil fuel impurities that cause byproduct emissions, CO2 is an inevitable result of hydrocarbon combustion. The energy density and CO2 footprint of a particular fuel depend on the hydrocarbon chain length and the complexity of its hydrocarbon molecules. Therefore, the footprint of gaseous hydrocarbon fuels is smaller than that of liquid hydrocarbon fuels, but the disadvantage is that gaseous hydrocarbon fuels are more challenging and more expensive to handle and store. In order to reduce the CO2 footprint, a large two-stroke single-flow scavenged turbocharged crosshead compression ignition internal combustion engine operated with hydrocarbon fuels has been proposed, which has a system for capturing and storing CO2.

[0004] One known CO2 capture and storage technology consists of equipping these large two-stroke, uniflow, scavenged, turbocharged, crosshead internal combustion engines with amine-based scrubbers. This is considered the most mature carbon capture solution currently and is currently planned to be installed on board ships as pilot and demonstration equipment in the next few years. The disadvantages of this technology are that amines degrade over time, as they are sensitive to SOx, NOx, O2, particulate matter and temperatures above about 150°C. Amines form harmful emissions, which must be controlled. The energy consumption of the reboiler is huge - up to 60% of the engine shaft power.

[0005] Another known CO2 capture and storage technology consists of equipping large two-stroke uniflow scavenged turbocharged crosshead internal combustion engines with EGR and upstream air separation (N2 and O2) followed by downstream CO2 liquefaction. The upstream air separation is performed by membranes. The disadvantages of this technology are that the air separation membranes are bulky, expensive, have high pressure losses, and can be fragile. Initially, this technology was tested in land-based power plants (to avoid NOx formation), but was never successful. In addition, when O2 and CO2 are separated in the exhaust, a large amount of O2 can be wasted.

[0006] Another known technology is to thermally crack / reform the fuel upstream into a mixture of H2 and CO2. H2 and CO2 are separated by a membrane, H2 is burned in a hydrogen engine, and CO2 is liquefied. The disadvantages of this technology are that thermal cracking / reforming requires a catalyst, which reduces the operating temperature and increases the selectivity of the reaction. The catalyst is expensive, may be sensitive to impurities in the fuel, has a limited service life, and the product stream from the cracking / reforming process may contain other substances (possibly CO, CH4) in addition to the required CO2+H2. The energy consumption of thermal cracking / reforming is about 40% of the engine shaft power. In addition, the technology requires a membrane to effectively separate H2 and CO2. There is little information about CO2 / H2 membrane separation, but cost, size and life must be considered. Finally, the technology requires the development of a large hydrogen-type two-stroke single-flow scavenged turbocharged crosshead internal combustion engine.

[0007] Another technology is a large two-stroke uniflow scavenged turbocharged crosshead internal combustion engine running on ammonia fuel synthesized from hydrogen and nitrogen. This technology is under development. The disadvantage of this technology is that ammonia is extremely toxic and corrosive to certain materials. Ammonia engines also require an SCR catalyst and possibly an N2O catalyst. Although carbon-free, ammonia ICEs can be expected to reduce the GWP by about 90% relative to diesel due to N2O emissions. The combustion characteristics of ammonia are very unsuitable for compression ignition (diesel) engines. Summary of the invention

[0008] The object is to provide a large two-stroke uniflow scavenged turbocharged crosshead internal combustion engine to overcome or at least reduce the above problems. Another object is to provide a method for eliminating or at least reducing gaseous CO2 emissions from a large two-stroke uniflow scavenged turbocharged crosshead internal combustion engine.

[0009] The above-mentioned objects and other objects are achieved by the features of the independent claims. Further implementations are apparent from the dependent claims, the description and the drawings.

[0010] According to a first aspect, there is provided a large two-stroke uniflow scavenged internal combustion engine, the engine comprising:

[0011] - a plurality of cylinders having a cylinder liner and a reciprocating piston located in the cylinder liner and a cylinder head covering the cylinder,

[0012] - a combustion chamber formed inside the cylinder liner 1 between the reciprocating piston and the cylinder head,

[0013] a scavenging port arranged in the cylinder liner for admitting scavenging gases into the combustion chamber,

[0014] an exhaust gas outlet which is arranged in the cylinder head and which is controlled by an exhaust valve,

[0015] an intake system comprising a scavenging gas receiver connected to the cylinder for supplying scavenging gas to a combustion chamber in the cylinder,

[0016] - a fuel system configured to supply a carbon-based fuel to the combustion chamber,

[0017] an exhaust system comprising an exhaust receiver coupled to the combustion chamber via an exhaust valve for receiving an exhaust gas flow resulting from the combustion of a carbon-based fuel in the combustion chamber,

[0018] Wherein the engine is a closed-loop oxygen-fuel engine and comprises:

[0019] a recirculation duct connecting the exhaust gas receiver to the purge gas receiver,

[0020] a blower located in the recirculation duct for compressing the exhaust gas from the exhaust gas receiver and forcing the compressed exhaust gas to the purge gas receiver,

[0021] an oxygen supply system configured to supply oxygen to the intake system, and

[0022] a separation and carbon dioxide liquefaction system, wherein a portion of the exhaust gas stream produced in the combustion chamber is diverted to the separation and carbon dioxide liquefaction system, the separation and carbon dioxide liquefaction system being configured to separate oxygen and carbon dioxide from the diverted exhaust gas stream by liquefying carbon dioxide from the diverted exhaust gas stream,

[0023] A transfer duct for diverting a diverted portion of the exhaust gas flow, the transfer duct being coupled to the recirculation loop, the transfer duct comprising a divert compressor and one or more coolers.

[0024] This large two-stroke single-flow scavenged internal combustion engine has no gaseous emissions. The energy consumption for oxygen separation and carbon dioxide liquefaction in this engine is relatively low compared to known technologies. Efficient oxygen and carbon dioxide separation minimizes O2 consumption. The engine is compatible with a variety of fuels and potential retrofit solutions. No rare or expensive rare earth metals are required, which are used in catalysts and known gas separation membrane carbon dioxide capture technologies. Another advantage of this engine is that the oxygen concentration in the scavenging air can be freely set. In addition, since the formation of NOx does not have to be considered, the SFOC (specific fuel consumption) is reduced, that is, the engine can be operated at higher combustion temperatures and pressures, thereby improving fuel efficiency.

[0025] In a possible realization form of the first aspect, the transfer duct is coupled to the recirculation circuit at a point downstream of the first cooler and preferably upstream of the blower.

[0026] In a possible realization form of the first aspect, one or more coolers are arranged downstream of the transfer compressor, the transfer conduit preferably opening into a separation and liquefaction vessel.

[0027] In a possible implementation form of the first aspect, the separation and carbon dioxide liquefaction system comprises: a compressor for compressing the transferred stream to a target pressure; and one or more heat exchangers for cooling the transferred stream to a target temperature, the combination of the desired pressure and the desired temperature causing the carbon dioxide in the steam to liquefy and thereby causing the liquefied carbon dioxide to be separated from the oxygen in the transferred stream in a separation vessel, the target pressure being preferably at least 7 bara and the target temperature being preferably below -50°C.

[0028] In a possible implementation form of the first aspect, the oxygen supply system includes a liquid oxygen tank.

[0029] In a possible implementation form of the first aspect, the carbon-based fuel is a hydrocarbon fuel, and combustion of the hydrocarbon fuel in the combustion chamber produces water, and the engine includes a water separation system configured to separate water from the exhaust gas flow.

[0030] In a possible implementation form of the first aspect, the engine comprises a first cooler in the recirculation duct for cooling the exhaust gas, the first cooler being arranged upstream of the blower.

[0031] In a possible implementation form of the first aspect, the first cooler is configured to separate water from the exhaust gas.

[0032] In a possible implementation form of the first aspect, the combustion chamber is configured to combust a carbon-based fuel with oxygen to generate an exhaust gas flow containing carbon dioxide.

[0033] In a possible implementation form of the first aspect, the mole fraction of carbon dioxide in the purge gas supplied to the combustion chamber is higher than 0.70 mol / mol.

[0034] In a possible implementation form of the first aspect, the mole fraction of nitrogen in the scavenging gas supplied to the combustion chamber is lower than 0.05 mol / mol.

[0035] In a possible implementation form of the first aspect, the mole fraction of oxygen in the scavenging gas supplied to the combustion chamber is higher than 0.17 mol / mol.

[0036] In a possible implementation form of the first aspect, at least one of the coolers in the transfer conduit is a heat exchanger that exchanges heat between the transferred exhaust gas and liquid oxygen supplied from the liquid oxygen source to the purge gas receiver.

[0037] According to a second aspect, there is provided a large two-stroke uniflow scavenged internal combustion engine, the engine comprising:

[0038] - a plurality of cylinders having a cylinder liner and a reciprocating piston located in the cylinder liner and a cylinder head covering the cylinder,

[0039] - a combustion chamber formed inside the cylinder liner between the reciprocating piston and the cylinder head,

[0040] a scavenging port arranged in the cylinder liner for admitting scavenging gases into the combustion chamber,

[0041] an exhaust gas outlet which is arranged in the cylinder head and which is controlled by an exhaust valve,

[0042] an intake system comprising a scavenging gas receiver connected to the cylinder for supplying scavenging gas to a combustion chamber in the cylinder,

[0043] - a fuel system configured to supply a carbon-based fuel to the combustion chamber,

[0044] an exhaust system comprising an exhaust receiver coupled to the combustion chamber via an exhaust valve for receiving an exhaust gas flow resulting from the combustion of a carbon-based fuel in the combustion chamber,

[0045] Characterized in that the engine is a closed-loop oxygen-fuel engine and comprises:

[0046] a recirculation duct connecting the exhaust gas receiver to the purge gas receiver,

[0047] a blower located in the recirculation duct for compressing the exhaust gas from the exhaust gas receiver and forcing the compressed exhaust gas to the purge gas receiver,

[0048] an oxygen supply system configured to supply oxygen to the intake system, and

[0049] a separation and carbon dioxide liquefaction system, wherein a portion of the exhaust gas stream produced in the combustion chamber is diverted to the separation and carbon dioxide liquefaction system, the separation and carbon dioxide liquefaction system being configured to separate oxygen and carbon dioxide from the diverted exhaust gas stream by liquefying carbon dioxide from the diverted exhaust gas stream,

[0050] The separation and carbon dioxide liquefaction system includes a compressor for compressing the transferred stream to a target pressure and one or more heat exchangers for cooling the transferred stream to a target temperature, the combination of the desired pressure and the desired temperature causing the carbon dioxide in the stream to liquefy and thereby separate the liquefied carbon dioxide from the oxygen in the transferred stream in a separation vessel.

[0051] According to a third aspect, there is provided a large two-stroke uniflow scavenged internal combustion engine, the engine comprising:

[0052] - a plurality of cylinders having a cylinder liner and a reciprocating piston located in the cylinder liner and a cylinder head covering the cylinder,

[0053] - a combustion chamber formed inside the cylinder liner between the reciprocating piston and the cylinder head,

[0054] a scavenging port arranged in the cylinder liner for admitting scavenging gases into the combustion chamber,

[0055] an exhaust gas outlet which is arranged in the cylinder head and which is controlled by an exhaust valve,

[0056] an intake system comprising a scavenging gas receiver connected to the cylinder for supplying scavenging gas to a combustion chamber in the cylinder,

[0057] - a fuel system configured to supply a carbon-based fuel to the combustion chamber,

[0058] an exhaust system comprising an exhaust receiver coupled to the combustion chamber via an exhaust valve for receiving an exhaust gas flow resulting from the combustion of a carbon-based fuel in the combustion chamber,

[0059] Characterized in that the engine is a closed-loop oxygen-fuel engine and comprises:

[0060] a recirculation duct connecting the exhaust gas receiver to the purge gas receiver,

[0061] a blower located in the recirculation duct for compressing the exhaust gas from the exhaust gas receiver and forcing the compressed exhaust gas to the purge gas receiver,

[0062] an oxygen supply system configured to supply oxygen to the intake system, and

[0063] - a separation and CO2 liquefaction system, to which a part of the exhaust gas flow produced in the combustion chamber is diverted, the separation and CO2 liquefaction system being configured to separate oxygen and carbon dioxide from the diverted exhaust gas flow by means of liquefying the carbon dioxide from the diverted exhaust gas flow, wherein the molar fraction of carbon dioxide in the purge gas supplied to the combustion chamber is higher than 0.70 mol / mol.

[0064] According to a fourth aspect, there is provided a large two-stroke uniflow scavenged internal combustion engine, the engine comprising:

[0065] - a plurality of cylinders having a cylinder liner and a reciprocating piston located in the cylinder liner and a cylinder head covering the cylinder,

[0066] - a combustion chamber formed inside the cylinder liner between the reciprocating piston and the cylinder head,

[0067] a scavenging port arranged in the cylinder liner for admitting scavenging gases into the combustion chamber,

[0068] an exhaust gas outlet which is arranged in the cylinder head and which is controlled by an exhaust valve,

[0069] an intake system comprising a scavenging gas receiver connected to the cylinder for supplying scavenging gas to a combustion chamber in the cylinder,

[0070] - a fuel system configured to supply a carbon-based fuel to the combustion chamber,

[0071] an exhaust system comprising an exhaust receiver coupled to the combustion chamber via an exhaust valve for receiving an exhaust gas flow resulting from the combustion of a carbon-based fuel in the combustion chamber,

[0072] Characterized in that the engine is a closed-loop oxygen-fuel engine and comprises:

[0073] a recirculation duct connecting the exhaust gas receiver to the purge gas receiver,

[0074] a blower located in the recirculation duct for compressing the exhaust gas from the exhaust gas receiver and forcing the compressed exhaust gas to the purge gas receiver,

[0075] an oxygen supply system configured to supply oxygen to the intake system, and

[0076] - a separation and CO2 liquefaction system, to which a portion of the exhaust gas flow produced in the combustion chamber is diverted, the separation and CO2 liquefaction system being configured to separate oxygen and carbon dioxide from the diverted exhaust gas flow by liquefying the carbon dioxide from the diverted exhaust gas flow, wherein the molar fraction of nitrogen in the purge gas supplied to the combustion chamber is less than 0.05 mol / mol.

[0077] According to a fifth aspect, there is provided a large two-stroke uniflow scavenging internal combustion engine, the engine comprising:

[0078] - a plurality of cylinders having a cylinder liner and a reciprocating piston located in the cylinder liner and a cylinder head covering the cylinder,

[0079] - a combustion chamber formed inside the cylinder liner between the reciprocating piston and the cylinder head,

[0080] a scavenging port arranged in the cylinder liner for admitting scavenging gases into the combustion chamber,

[0081] an exhaust gas outlet which is arranged in the cylinder head and which is controlled by an exhaust valve,

[0082] an intake system comprising a scavenging gas receiver connected to the cylinder for supplying scavenging gas to a combustion chamber in the cylinder,

[0083] - a fuel system configured to supply a carbon-based fuel to the combustion chamber,

[0084] an exhaust system comprising an exhaust receiver coupled to the combustion chamber via an exhaust valve for receiving an exhaust gas flow resulting from the combustion of a carbon-based fuel in the combustion chamber,

[0085] Characterized in that the engine is a closed-loop oxygen-fuel engine and comprises:

[0086] a recirculation duct connecting the exhaust gas receiver to the purge gas receiver,

[0087] a blower located in the recirculation duct for compressing the exhaust gas from the exhaust gas receiver and forcing the compressed exhaust gas to the purge gas receiver,

[0088] an oxygen supply system configured to supply oxygen to the intake system, and

[0089] - a separation and CO2 liquefaction system, to which a portion of the exhaust gas flow produced in the combustion chamber is diverted, the separation and CO2 liquefaction system being configured to separate oxygen and carbon dioxide from the diverted exhaust gas flow by liquefying the carbon dioxide from the diverted exhaust gas flow, wherein the molar fraction of oxygen in the purge gas supplied to the combustion chamber is higher than 0.17 mol / mol.

[0090] According to a sixth aspect, there is provided a large two-stroke uniflow scavenging internal combustion engine, the engine comprising:

[0091] - a plurality of cylinders having a cylinder liner and a reciprocating piston located in the cylinder liner and a cylinder head covering the cylinder,

[0092] - a combustion chamber formed inside the cylinder liner between the reciprocating piston and the cylinder head,

[0093] a scavenging port arranged in the cylinder liner for admitting scavenging gases into the combustion chamber,

[0094] an exhaust gas outlet which is arranged in the cylinder head and which is controlled by an exhaust valve,

[0095] an intake system comprising a scavenging gas receiver connected to the cylinder for supplying scavenging gas to a combustion chamber in the cylinder,

[0096] - a fuel system configured to supply a carbon-based fuel to the combustion chamber,

[0097] an exhaust system comprising an exhaust receiver coupled to the combustion chamber via an exhaust valve for receiving an exhaust gas flow resulting from the combustion of a carbon-based fuel in the combustion chamber,

[0098] Characterized in that the engine is a closed-loop oxygen-fuel engine and comprises:

[0099] a recirculation duct connecting the exhaust gas receiver to the purge gas receiver,

[0100] a blower located in the recirculation duct for compressing the exhaust gas from the exhaust gas receiver and forcing the compressed exhaust gas to the purge gas receiver,

[0101] an oxygen supply system configured to supply oxygen to the intake system, and

[0102] - a separation and carbon dioxide liquefaction system, wherein a portion of the exhaust gas flow generated in the combustion chamber is transferred to the separation and carbon dioxide liquefaction system, which is configured to separate oxygen and carbon dioxide from the transferred exhaust gas flow by means of liquefying the carbon dioxide from the transferred exhaust gas flow.

[0103] According to a seventh aspect, there is provided a large two-stroke uniflow scavenging internal combustion engine, the engine comprising:

[0104] - a plurality of cylinders having a cylinder liner and a reciprocating piston located in the cylinder liner and a cylinder head covering the cylinder,

[0105] - a combustion chamber formed inside the cylinder liner between the reciprocating piston and the cylinder head,

[0106] a scavenging port arranged in the cylinder liner for admitting scavenging gases into the combustion chamber,

[0107] an exhaust gas outlet which is arranged in the cylinder head and which is controlled by an exhaust valve,

[0108] an intake system comprising a scavenging gas receiver connected to the cylinder for supplying scavenging gas to a combustion chamber in the cylinder,

[0109] - a fuel system configured to supply a carbon-based fuel to the combustion chamber,

[0110] an exhaust system comprising an exhaust receiver coupled to the combustion chamber via an exhaust valve for receiving an exhaust gas flow resulting from the combustion of a carbon-based fuel in the combustion chamber,

[0111] Characterized in that the engine is a closed-loop oxygen-fuel engine and comprises:

[0112] a recirculation duct connecting the exhaust gas receiver to the purge gas receiver,

[0113] a blower located in the recirculation duct for compressing the exhaust gas from the exhaust gas receiver and forcing the compressed exhaust gas to the purge gas receiver,

[0114] an oxygen supply system configured to supply oxygen to the intake system, and

[0115] - a separation and carbon dioxide liquefaction system, wherein a portion of the exhaust gas stream generated in the combustion chamber is transferred to the separation and carbon dioxide liquefaction system, the separation and carbon dioxide liquefaction system being configured to separate oxygen and carbon dioxide from the transferred exhaust gas stream by means of liquefying carbon dioxide from the transferred exhaust gas stream, wherein the oxygen supply system comprises a liquid oxygen tank, and wherein at least one of the coolers in the transfer line is a heat exchanger which exchanges heat between the transferred exhaust gas and liquid oxygen supplied by a liquid oxygen source to a purge gas receiver.

[0116] These and other aspects will be apparent from the drawings and from one or more embodiments described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0117] In the following detailed description of the present disclosure, various aspects, embodiments and implementations will be described in more detail with reference to example embodiments shown in the accompanying drawings, in which:

[0118] Figure 1 is a front elevation view of a large two-stroke internal combustion engine according to an embodiment,

[0119] Figure 2 yes Figure 1 A side elevation view of a large two-stroke engine.

[0120] Figure 3 It has a separation and carbon dioxide liquefaction system Figure 1 A schematic diagram of an embodiment of a large two-stroke engine, and

[0121] Figure 4 It has a separation and carbon dioxide liquefaction system Figure 1 Schematic diagram of an embodiment of a large two-stroke engine. DETAILED DESCRIPTION

[0122] In the following detailed description, the internal combustion engine will be described with reference to a large two-stroke, low-speed, uniflow, scavenged, turbocharged, crosshead internal combustion engine in an exemplary embodiment. The large two-stroke, low-speed, uniflow, scavenged, turbocharged, crosshead internal combustion engine may be of the following (high pressure) type: in the (high pressure) type engine, the fuel is injected at or near the top dead center (TDC) of the piston, i.e., compression ignition, or of the (low pressure) type engine, in which the fuel is mixed with the scavenging air before or during compression (premixed engine), and the mixture of air and fuel is ignited by spark ignition or the like. In a premixed engine, a "pilot" ignition is usually performed at or near TDC by an ignition fluid, such as fuel oil, to ensure reliable ignition.

[0123] Figure 1 , Figure 2 and Figure 3 There is shown a large, low speed, turbocharged, two-stroke engine having a crankshaft 8 and a crosshead 9, the engine being configured to operate according to the Diesel principle, ie the engine is a compression ignition engine. Figure 3 A schematic diagram of a large, low-speed, turbocharged, two-stroke diesel engine and the intake and exhaust systems of the engine is shown. In this exemplary embodiment, the engine has six cylinders in line. Large, low-speed, turbocharged, two-stroke internal combustion engines typically have four to fourteen cylinders in line carried by a cylinder frame 23, which is carried by the engine frame 11. The engine can be used, for example, as a main engine in a marine vessel or as a stationary engine for operating a generator in a power station. The total output of the engine is, for example, in the range of 1,000 kW to 110,000 kW.

[0124] The engine can be configured as a dual fuel engine. The engine can be a compression ignition engine or a premixed engine. The engine according to the present embodiment is a two-stroke uniflow engine, wherein there is a scavenging port 18 in the lower region of the cylinder liner 1 and a central exhaust valve 4 at the top of each cylinder liner 1. The engine has at least one mode in which the engine is operated with a carbon-based fuel such as natural gas, methanol, dimethyl ether (DME) or fuel oil (e.g. marine diesel).

[0125] The scavenging gas is delivered from the scavenging gas receiver 2 to the scavenging port 18 of each cylinder 1. The piston 10 reciprocating between the bottom dead center (BDC) and the top dead center (TDC) in the cylinder liner 1 compresses the scavenging gas. When the piston is at or close to TDC, the fuel is injected into the combustion chamber at high pressure through the fuel valve 50 arranged in the cylinder head 22 (diesel principle-compression ignition). When the engine is configured as a premixed engine, when the piston moves toward TDC (Otto principle-premixed engine), the fuel is allowed to enter from the fuel admission valve (usually there are 2 or more fuel admission valves for each cylinder) at a relatively low pressure. The fuel admission valve can be arranged in the cylinder liner at a position above the scavenging port 18, or arranged in the cylinder head 22. Combustion is then carried out and exhaust gas is produced. If the engine is configured as compression ignition, each cylinder head 22 is provided with two or more fuel valves 50. The fuel valve 50 is configured to inject fuel only into the combustion chamber. The fuel valve 50 is arranged in the cylinder head 22 around the central exhaust valve 4. In addition, an additional, usually smaller fuel valve (not shown) is optionally provided in the cylinder head 22 for injecting an ignition fluid to ensure reliable ignition of the fuel (e.g., a gaseous fuel). The ignition fluid is, for example, dimethyl ether (DME) or fuel oil, but may also be another form of ignition enhancer, such as hydrogen. In an embodiment (not shown), the fuel valve is arranged along the cylinder liner (indicated by a dotted line) and allows fuel to enter the cylinder before the piston 10 passes through the fuel valve on the way from BDC to TDC. Therefore, when the engine is configured for premixed operation, the piston 10 compresses a mixture of scavenging air and fuel. Timing ignition at or near TDC is triggered by sparks, lasers, ignition fluid injection, etc. In an embodiment having a fuel valve, the pressure at which fuel is admitted is much lower than the pressure at which fuel is injected in the following embodiment: this embodiment has a fuel valve 50 located in the cylinder head 22, which injects when the piston is at or near top dead center (TDC), and the pressure at which fuel is injected needs to be significantly higher than the compression pressure.

[0126] When the exhaust valve 4 is open, the exhaust gas flows through the exhaust pipe associated with the cylinder into the exhaust gas receiver 3 and continues to flow through the recirculation pipe 5 via the first cooler 14 to the blower 7, from which the exhaust gas flows back to the scavenging gas receiver 2. If the fuel is a hydrocarbon fuel and therefore produces water during combustion, the cooler 40 will be configured to remove most of the water from the exhaust gas flow and transfer the water to the water tank 16. A portion of the exhaust gas is preferably transferred from the recirculation pipe 5 to the separation and carbon dioxide liquefaction system 60 at a location downstream of the first cooler 14 and upstream of the blower 7. The separation and carbon dioxide liquefaction system 60 liquefies the carbon dioxide and stores the liquefied carbon dioxide in the liquefied carbon dioxide storage tank 49, and delivers oxygen separated from the carbon dioxide in the transferred exhaust gas flow to the scavenging gas receiver 60. The oxygen source, i.e., the supply system 12, in this embodiment, is a liquid oxygen tank 12, feeds the oxygen flow to the scavenging air receiver 2.

[0127] The compressed exhaust gas leaving the blower 7 is mixed with oxygen from the oxygen supply system 12 in the scavenging air receiver to form scavenging gas which is ready to be supplied to the combustion chamber in the cylinder liner 1 through the scavenging ports 18 .

[0128] Now referring to 4, in particular, the separation and carbon dioxide liquefaction system is disclosed in more detail Figures 1 to 3The engine of the embodiment. In this scheme of the embodiment, the engine is operated with hydrocarbon fuel, and therefore, the combustion gas includes both water and carbon dioxide. Therefore, the first cooler 14 is configured to condense and separate most of the water in the exhaust gas. The water condensed and separated from the exhaust gas is transported to the water tank 16 through the pipeline 15. A portion of the exhaust gas leaving the first cooler 14 is transferred from the cooled exhaust gas mainstream to the transfer pipeline 40. In an embodiment, the amount of exhaust gas transferred from the recirculation pipeline 5 is regulated by a control valve 38 arranged in the transfer pipeline 40. The amount of exhaust gas transferred is regulated to correspond to the amount of carbon dioxide produced during the combustion process, so that the total amount of carbon dioxide recirculated in the engine is substantially constant. Preferably, the engine includes a controller (not shown), such as a microcontroller, which is aware of the amount of carbon in the injected fuel, and is configured to calculate the amount of carbon dioxide produced by combustion, and is configured to regulate the amount of exhaust gas transferred accordingly. The rest of the exhaust gas from the first cooler 14 enters the blower 7 and enters the scavenging air receiver 2 from the blower 7 as compressed exhaust gas. However, it should be understood that engine operation may be controlled in a different manner without determining the amount of carbon dioxide that needs to be removed, and for example, an absolute pressure in the exhaust gas receiver may be used as a parameter for determining how much exhaust gas carbon dioxide needs to be removed. In this example, the controller uses a reference pressure in the exhaust gas receiver or a reference pressure that is a function of engine operating conditions, such as engine load, to increase, decrease, or maintain the amount of carbon dioxide to be removed, such as when the determined or measured pressure in the exhaust gas receiver is above the reference pressure, more carbon dioxide is removed, when the determined or measured pressure in the exhaust gas receiver is below the reference pressure, less carbon dioxide is removed, and when the determined or measured pressure in the exhaust gas receiver is within an allowable bandwidth about the reference pressure, there is no change in the amount of carbon dioxide removed.

[0129] The transfer pipeline 40 comprises a compressor 42. The compressor is configured to significantly increase the pressure of the transferred exhaust gas, for example by at least 40 bar. Downstream of the compressor 42, a second cooler 44 is provided. The second cooler 44 will condense any remaining water, and this water will be separated and delivered to the water tank 16. A third cooler 45 is arranged downstream of the second cooler. The third cooler 45 is a heat exchanger that exchanges heat with liquid oxygen from the liquid oxygen tank 61 delivered to the purge gas receiver 2 via the production pipeline 63.

[0130] The fourth cooler 46 is arranged downstream of the third cooler 45. The fourth cooler 46 performs heat exchange with a mixture of oxygen and carbon dioxide from the carbon dioxide liquefaction and oxygen separation container 47 and from the liquefied carbon dioxide storage tank 49. The transfer pipeline leads to the carbon dioxide liquefaction and oxygen separation container 47. When the transferred exhaust gas leaves the fourth cooler 46, the temperature is low enough and the pressure is high enough to liquefy the carbon dioxide in the transferred exhaust gas in the carbon dioxide liquefaction and oxygen separation container 47, and thus separate from the oxygen that is not liquefied at these temperatures and pressures. Therefore, the lower part of the carbon dioxide liquefaction and oxygen separation container 47 will contain liquefied carbon dioxide, and the upper part of the carbon dioxide liquefaction and oxygen separation container 47 will contain a mixture of oxygen and carbon dioxide in the gas phase. The lower part of the carbon dioxide liquefaction and oxygen separation container 47 is connected to the liquefied carbon dioxide tank 49 through a liquefied carbon dioxide pipeline 48. The lower part of the liquefied carbon dioxide tank 49 contains liquefied carbon dioxide, and the upper part of the liquefied carbon dioxide tank 49 contains a mixture of oxygen and carbon dioxide in the gas phase. The mixture in the gas phase in the carbon dioxide liquefaction and oxygen separation vessel 47 and preferably also in the liquefied carbon dioxide tank 49 is conveyed to the purge gas receiver 2 in the oxygen return conduit 43 via expansion valves 65 and 66, respectively. The optional return conduit 43 passes through a fourth cooler 46 in an embodiment to exchange heat with the diverted exhaust gas.

[0131] The amount of oxygen in the sweep gas is regulated by adjusting the flow of liquid oxygen from the liquid oxygen tank 61 via the liquid oxygen supply line 63 to the sweep gas receiver 3. The flow is regulated by a control valve 64 arranged in the oxygen supply line 63 and preferably the flow is under the control of a controller.

[0132] A bypass conduit 25 extends from the exhaust receiver 3 to the scavenging gas receiver 2 for bypassing the blower 7. A bypass control valve 26 regulates the gas flow from the scavenging gas receiver 2 to the exhaust receiver 3. The bypass valve is used as a process control handle. By allowing carbon dioxide-rich gas (before oxygen enrichment) to bypass the cylinder and return to the exhaust receiver, the amount of over-scavenging can be reduced. In this way, the amount of short-circuited oxygen can be minimized. In addition, the scavenging efficiency can be reduced so that hot residual gas remains in the cylinder until the next cycle. In this way, higher compression temperatures can be achieved, if necessary, for example to avoid knocking tendencies.

[0133] Example

[0134] Example operating conditions using a fuel of Sfoc = 362 g CH3OH / kWh and assuming a thermal efficiency of 50%:

[0135] In the exhaust gas receiver, the temperature of the exhaust gas is typically between 400° C. and 500° C., the pressure is about 4 bar, yCO2 is about 0.85 mol / mol, and yO2 is about 0.15 mol / mol.

[0136] Downstream of the first cooler 14, the exhaust gas has a temperature of typically about 5°C and a pressure of about 4 bar, yCO2 of about 0.85 mol / mol, and yO2 of about 0.15 mol / mol.

[0137] The blower 7 increases the pressure by 0.3 bar.

[0138] In the purge gas receiver, the purge gas has a temperature of about 10° C. and a pressure of about 4.3 bar. yCO2 is about 0.79 mol / mol, and yO2 is about 0.21 mol / mol.

[0139] The compressor increases the pressure of the diverted exhaust gas by about 41 bar, and downstream of the second cooler 44 the diverted exhaust gas has a temperature of 10° C. and a pressure of about 45 bar. yCO2=0.79 mol / mol, and yO2=0.21 mol / mol.

[0140] When the diverted exhaust gas reaches the carbon dioxide liquefaction and oxygen separation vessel 47, the temperature is minus 20°C and the pressure is about 45 bar.

[0141] The temperature of the liquid oxygen in the liquid oxygen tank 61 is about -140°C, and the pressure is about 20 bar.

[0142] Various aspects and embodiments are described herein in conjunction with various embodiments. However, other variations of the disclosed embodiments may be understood and implemented by those skilled in the art in practicing the claimed subject matter by studying the drawings, the disclosure, and the appended claims. In the claims, the term "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The reference numerals used in the claims should not be interpreted as limiting the scope. Unless otherwise indicated, the drawings are intended to be read together with the application documents (e.g., section lines, component arrangement structures, proportions, degrees, etc.), and the drawings should be considered part of the entire written description of the present disclosure.

Claims

1. A large two-stroke single-flow scavenging internal combustion engine, the engine comprising: - a plurality of cylinders, each cylinder having a cylinder liner (1) and a reciprocating piston (10) located in the cylinder liner (1) and a cylinder head (22) covering the cylinder, - a combustion chamber formed inside the cylinder liner (1) between the reciprocating piston (10) and the cylinder head (22), a scavenging port (18) arranged in the cylinder liner (1) for admitting scavenging gases into the combustion chamber, an exhaust outlet, which is arranged in the cylinder head (22) and which is controlled by an exhaust valve (4), an intake system comprising a scavenging gas receiver (2) connected to the cylinder for supplying scavenging gas to the combustion chamber in the cylinder, a fuel system (30) configured to supply a carbon-based fuel to the combustion chamber, an exhaust system comprising an exhaust receiver (3) connected to the combustion chamber via the exhaust valve (4) for receiving an exhaust gas flow resulting from the combustion of the carbon-based fuel in the combustion chamber, Characterized in that the engine is a closed-loop oxygen-fuel engine and comprises: a recirculation duct (5) connecting the exhaust gas receiver (3) to the purge gas receiver (2), a blower (7) located in the recirculation duct (5) for compressing the exhaust gas from the exhaust gas receiver (3) and forcing the compressed exhaust gas to the purge gas receiver (2), - an oxygen supply system (12) configured to supply oxygen to the intake system, and a separation and carbon dioxide liquefaction system (60), wherein a portion of the exhaust gas stream generated in the combustion chamber is transferred to the separation and carbon dioxide liquefaction system (60), the separation and carbon dioxide liquefaction system (60) being configured to separate oxygen and carbon dioxide from the transferred exhaust gas stream by liquefying carbon dioxide from the transferred exhaust gas stream, a transfer duct (40) for diverting the diverted portion of the exhaust gas flow, the transfer duct (40) being connected to the recirculation loop (5), the transfer duct (40) comprising a transfer compressor (42) and one or more coolers (44, 45, 46).

2. The engine according to claim 1, wherein: The transfer conduit (40) is coupled to the recirculation loop (5) at a location downstream of the first cooler (14).

3. The engine according to claim 1 or 2, wherein: The one or more coolers (44, 45, 46) are arranged in the transfer conduit (40) downstream of the transfer compressor (42).

4. The engine according to any one of claims 1 to 3, wherein: The separation and carbon dioxide liquefaction system (60) includes a compressor (42) for compressing the diverted stream to a target pressure and one or more heat exchangers (44, 45, 46) for cooling the diverted stream to a target temperature, the combination of the desired pressure and the desired temperature causing the carbon dioxide in the steam to liquefy and thereby separate the liquefied carbon dioxide from the oxygen in the diverted stream in a separation vessel (49).

5. The engine according to any one of claims 1 to 4, wherein: The oxygen supply system (12) comprises a liquid oxygen tank (61).

6. The engine according to any one of claims 1 to 5, wherein: The carbon-based fuel is a hydrocarbon fuel, and combustion of the hydrocarbon fuel in the combustion chamber produces water, the engine comprising a water separation system (14, 15, 16) configured to separate water from the exhaust gas flow.

7. An engine according to any one of claims 1 to 6, comprising a first cooler (14) in the recirculation duct (5), the first cooler (14) being used to cool the exhaust gas.

8. An engine according to claim 7 as dependent on claim 6, wherein: The first cooler (14) is configured to separate water from the exhaust gas.

9. The engine according to any one of claims 1 to 8, wherein: The combustion chamber is configured to combust the carbon-based fuel with oxygen to produce an exhaust stream containing carbon dioxide.

10. An engine according to any one of claims 1 to 9, wherein: The mole fraction of carbon dioxide in the purge gas supplied to the combustion chamber is higher than 0.70 mol / mol.

11. An engine according to any one of claims 1 to 10, wherein: The mole fraction of nitrogen in the purge gas supplied to the combustion chamber is lower than 0.05 mol / mol.

12. An engine according to any one of claims 1 to 11, wherein: The mole fraction of oxygen in the scavenging gas supplied to the combustion chamber is higher than 0.17 mol / mol.

13. An engine according to any one of claims 5 to 12, wherein: At least one of the coolers (45) in the transfer conduit (40) is a heat exchanger that exchanges heat between the transferred exhaust gas and liquid oxygen supplied from a liquid oxygen source (61) to the purge gas receiver (2).

14. A large two-stroke uniflow scavenging internal combustion engine, the engine comprising: - a plurality of cylinders, each cylinder having a cylinder liner (1) and a reciprocating piston (10) located in the cylinder liner (1) and a cylinder head (22) covering the cylinder, - a combustion chamber formed inside the cylinder liner (1) between the reciprocating piston (10) and the cylinder head (22), a scavenging port (18) arranged in the cylinder liner (1) for admitting scavenging gases into the combustion chamber, an exhaust outlet, which is arranged in the cylinder head (22) and which is controlled by an exhaust valve (4), an intake system comprising a scavenging gas receiver (2) connected to the cylinder for supplying scavenging gas to the combustion chamber in the cylinder, a fuel system (30) configured to supply a carbon-based fuel to the combustion chamber, an exhaust system comprising an exhaust receiver (3) connected to the combustion chamber via the exhaust valve (4) for receiving an exhaust gas flow resulting from the combustion of the carbon-based fuel in the combustion chamber, Characterized in that the engine is a closed-loop oxygen-fuel engine and comprises: a recirculation duct (5) connecting the exhaust gas receiver (3) to the purge gas receiver (2), a blower (7) located in the recirculation duct (5) for compressing the exhaust gas from the exhaust gas receiver (3) and forcing the compressed exhaust gas to the purge gas receiver (2), - an oxygen supply system (12) configured to supply oxygen to the intake system, and a separation and carbon dioxide liquefaction system (60), wherein a portion of the exhaust gas stream generated in the combustion chamber is transferred to the separation and carbon dioxide liquefaction system (60), the separation and carbon dioxide liquefaction system (60) being configured to separate oxygen and carbon dioxide from the transferred exhaust gas stream by liquefying carbon dioxide from the transferred exhaust gas stream, The separation and carbon dioxide liquefaction system (60) includes a compressor (42) for compressing the transferred stream to a target pressure and one or more heat exchangers (44, 45, 46) for cooling the transferred stream to a target temperature, the combination of the desired pressure and the desired temperature causing the carbon dioxide in the steam to liquefy and thereby separate the liquefied carbon dioxide from the oxygen in the transferred stream in a separation vessel (49).

15. A large two-stroke uniflow scavenging internal combustion engine, the engine comprising: - a plurality of cylinders, each cylinder having a cylinder liner (1) and a reciprocating piston (10) located in the cylinder liner (1) and a cylinder head (22) covering the cylinder, - a combustion chamber formed inside the cylinder liner (1) between the reciprocating piston (10) and the cylinder head (22), a scavenging port (18) arranged in the cylinder liner (1) for admitting scavenging gases into the combustion chamber, an exhaust outlet, which is arranged in the cylinder head (22) and which is controlled by an exhaust valve (4), an intake system comprising a scavenging gas receiver (2) connected to the cylinder for supplying scavenging gas to the combustion chamber in the cylinder, a fuel system (30) configured to supply a carbon-based fuel to the combustion chamber, an exhaust system comprising an exhaust receiver (3) connected to the combustion chamber via the exhaust valve (4) for receiving an exhaust gas flow resulting from the combustion of the carbon-based fuel in the combustion chamber, Characterized in that the engine is a closed-loop oxygen-fuel engine and comprises: a recirculation duct (5) connecting the exhaust gas receiver (3) to the purge gas receiver (2), a blower (7) located in the recirculation duct (5) for compressing the exhaust gas from the exhaust gas receiver (3) and forcing the compressed exhaust gas to the purge gas receiver (2), - an oxygen supply system (12) configured to supply oxygen to the intake system, and - a separation and carbon dioxide liquefaction system (60), wherein a portion of the exhaust gas flow generated in the combustion chamber is transferred to the separation and carbon dioxide liquefaction system (60), the separation and carbon dioxide liquefaction system (60) being configured to separate oxygen and carbon dioxide from the transferred exhaust gas flow by liquefying the carbon dioxide from the transferred exhaust gas flow, wherein the molar fraction of carbon dioxide in the purge gas supplied to the combustion chamber is higher than 0.70 mol / mol.

16. A large two-stroke uniflow scavenging internal combustion engine, the engine comprising: - a plurality of cylinders, each cylinder having a cylinder liner (1) and a reciprocating piston (10) located in the cylinder liner (1) and a cylinder head (22) covering the cylinder, - a combustion chamber formed inside the cylinder liner (1) between the reciprocating piston (10) and the cylinder head (22), a scavenging port (18) arranged in the cylinder liner (1) for admitting scavenging gases into the combustion chamber, an exhaust outlet, which is arranged in the cylinder head (22) and which is controlled by an exhaust valve (4), an intake system comprising a scavenging gas receiver (2) connected to the cylinder for supplying scavenging gas to the combustion chamber in the cylinder, a fuel system (30) configured to supply a carbon-based fuel to the combustion chamber, an exhaust system comprising an exhaust receiver (3) connected to the combustion chamber via the exhaust valve (4) for receiving an exhaust gas flow resulting from the combustion of the carbon-based fuel in the combustion chamber, Characterized in that the engine is a closed-loop oxygen-fuel engine and comprises: a recirculation duct (5) connecting the exhaust gas receiver (3) to the purge gas receiver (2), a blower (7) located in the recirculation duct (5) for compressing the exhaust gas from the exhaust gas receiver (3) and forcing the compressed exhaust gas to the purge gas receiver (2), - an oxygen supply system (12) configured to supply oxygen to the intake system, and - a separation and carbon dioxide liquefaction system (60), wherein a portion of the exhaust gas flow generated in the combustion chamber is transferred to the separation and carbon dioxide liquefaction system (60), the separation and carbon dioxide liquefaction system (60) being configured to separate oxygen and carbon dioxide from the transferred exhaust gas flow by liquefying carbon dioxide from the transferred exhaust gas flow, wherein the molar fraction of nitrogen in the purge gas supplied to the combustion chamber is less than 0.05 mol / mol.

17. A large two-stroke uniflow scavenging internal combustion engine, the engine comprising: - a plurality of cylinders, each cylinder having a cylinder liner (1) and a reciprocating piston (10) located in the cylinder liner (1) and a cylinder head (22) covering the cylinder, - a combustion chamber formed inside the cylinder liner (1) between the reciprocating piston (10) and the cylinder head (22), a scavenging port (18) arranged in the cylinder liner (1) for admitting scavenging gases into the combustion chamber, an exhaust outlet, which is arranged in the cylinder head (22) and which is controlled by an exhaust valve (4), an intake system comprising a scavenging gas receiver (2) connected to the cylinder for supplying scavenging gas to the combustion chamber in the cylinder, a fuel system (30) configured to supply a carbon-based fuel to the combustion chamber, an exhaust system comprising an exhaust receiver (3) connected to the combustion chamber via the exhaust valve (4) for receiving an exhaust gas flow resulting from the combustion of the carbon-based fuel in the combustion chamber, Characterized in that the engine is a closed-loop oxygen-fuel engine and comprises: a recirculation duct (5) connecting the exhaust gas receiver (3) to the purge gas receiver (2), a blower (7) located in the recirculation duct (5) for compressing the exhaust gas from the exhaust gas receiver (3) and forcing the compressed exhaust gas to the purge gas receiver (2), - an oxygen supply system (12) configured to supply oxygen to the intake system, and - a separation and carbon dioxide liquefaction system (60), wherein a portion of the exhaust gas flow generated in the combustion chamber is transferred to the separation and carbon dioxide liquefaction system (60), the separation and carbon dioxide liquefaction system (60) being configured to separate oxygen and carbon dioxide from the transferred exhaust gas flow by means of liquefying carbon dioxide from the transferred exhaust gas flow, wherein the molar fraction of oxygen in the purge gas supplied to the combustion chamber is higher than 0.17 mol / mol.

18. A large two-stroke uniflow scavenging internal combustion engine, the engine comprising: - a plurality of cylinders, each cylinder having a cylinder liner (1) and a reciprocating piston (10) located in the cylinder liner (1) and a cylinder head (22) covering the cylinder, - a combustion chamber formed inside the cylinder liner (1) between the reciprocating piston (10) and the cylinder head (22), a scavenging port (18) arranged in the cylinder liner (1) for admitting scavenging gases into the combustion chamber, an exhaust outlet, which is arranged in the cylinder head (22) and which is controlled by an exhaust valve (4), an intake system comprising a scavenging gas receiver (2) connected to the cylinder for supplying scavenging gas to the combustion chamber in the cylinder, a fuel system (30) configured to supply a carbon-based fuel to the combustion chamber, an exhaust system comprising an exhaust receiver (3) connected to the combustion chamber via the exhaust valve (4) for receiving an exhaust gas flow resulting from the combustion of the carbon-based fuel in the combustion chamber, Characterized in that the engine is a closed-loop oxygen-fuel engine and comprises: a recirculation duct (5) connecting the exhaust gas receiver (3) to the purge gas receiver (2), a blower (7) located in the recirculation duct (5) for compressing the exhaust gas from the exhaust gas receiver (3) and forcing the compressed exhaust gas to the purge gas receiver (2), - an oxygen supply system (12) configured to supply oxygen to the intake system, and - a separation and carbon dioxide liquefaction system (60), wherein a portion of the exhaust gas flow generated in the combustion chamber is transferred to the separation and carbon dioxide liquefaction system (60), the separation and carbon dioxide liquefaction system (60) being configured to separate oxygen and carbon dioxide from the transferred exhaust gas flow by liquefying the carbon dioxide from the transferred exhaust gas flow.

19. A large two-stroke uniflow scavenging internal combustion engine, the engine comprising: - a plurality of cylinders, each cylinder having a cylinder liner (1) and a reciprocating piston (10) located in the cylinder liner (1) and a cylinder head (22) covering the cylinder, - a combustion chamber formed inside the cylinder liner (1) between the reciprocating piston (10) and the cylinder head (22), a scavenging port (18) arranged in the cylinder liner (1) for admitting scavenging gases into the combustion chamber, an exhaust outlet, which is arranged in the cylinder head (22) and which is controlled by an exhaust valve (4), an intake system comprising a scavenging gas receiver (2) connected to the cylinder for supplying scavenging gas to the combustion chamber in the cylinder, a fuel system (30) configured to supply a carbon-based fuel to the combustion chamber, an exhaust system comprising an exhaust receiver (3) connected to the combustion chamber via the exhaust valve (4) for receiving an exhaust gas flow resulting from the combustion of the carbon-based fuel in the combustion chamber, Characterized in that the engine is a closed-loop oxygen-fuel engine and comprises: a recirculation duct (5) connecting the exhaust gas receiver (3) to the purge gas receiver (2), a blower (7) located in the recirculation duct (5) for compressing the exhaust gas from the exhaust gas receiver (3) and forcing the compressed exhaust gas to the purge gas receiver (2), - an oxygen supply system (12) configured to supply oxygen to the intake system, and - a separation and carbon dioxide liquefaction system (60), wherein a portion of the exhaust gas stream generated in the combustion chamber is transferred to the separation and carbon dioxide liquefaction system (60), the separation and carbon dioxide liquefaction system (60) being configured to separate oxygen and carbon dioxide from the transferred exhaust gas stream by means of liquefying carbon dioxide from the transferred exhaust gas stream, wherein the oxygen supply system (12) comprises a liquid oxygen tank (61), and wherein at least one of the coolers (45) in the transfer pipe (40) is a heat exchanger, which performs heat exchange between the transferred exhaust gas and liquid oxygen supplied by a liquid oxygen source (61) to the purge gas receiver (2).

Images