Device and method for providing a reducing agent

Abstract

To provide a reducer providing device 1 of a combustion engine.SOLUTION: A device 1 has a reducer providing section 2 having a reactor 3b and a reductant supply unit 3a for reducer liquid. The reactor 3b has a heating system 4 including a heating control unit 5 and a heating element 6 for heating an inside volume portion and / or contents 7 of the reactor 3b. The device 1 further has a supply system 8 suitable for dispensing a reducer gas and a reducer liquid to an exhaust gas. The supply system 8 has first piping 18 for guiding the reducer liquid and the reducer gas from the reactor to the exhaust gas, and an output line 15 is connected to the heating control unit 5 of the heating system 4 of the reactor 3b. The control unit is designed to start heating of the inside volume portion and / or the contents of the reactor to provide the reducer gas according to necessity, or to guide the reducer liquid to the exhaust gas through a non-heating reactor.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention is related to a device and method for providing a reducing agent, an exhaust aftertreatment system, and a combustion machine.

[0002] The present invention relates to the technical field of combustion engines and their emissions reduction.

[0003] The present invention preferably relates to an internal combustion engine such as a large marine or ship engine having a cylinder with an inner diameter of at least 200 mm, or a stationary engine. The engine is preferably a two-stroke engine or a two-stroke cross-head engine. The engine can be a diesel or gas engine, a dual-fuel or multi-fuel engine. It is possible to burn liquid and / or gaseous fuel in such an engine, either with self-ignition or forced ignition.

Background Art

[0004] The internal combustion engine can be a longitudinally scavenged two-stroke engine.

[0005] The term internal combustion engine also refers to large engines that can be operated in the Otto mode characterized by spark ignition of the fuel, as well as in the Diesel mode characterized by self-ignition of the fuel, or a mixture of the two. Further, the term internal combustion engine specifically includes dual-fuel engines and large engines in which the self-ignition of one fuel is used for the spark ignition of another fuel.

[0006] The engine speed is preferably below 800 RPM, especially for four-stroke engines, and more preferably below 200 RPM, especially for two-stroke engines, which indicates the designation of a low-speed engine.

[0007] The fuel can be diesel or marine diesel oil, or heavy fuel oil, or emulsion, or slurry, or methanol, or ethanol, and gases such as liquefied natural gas (LNG), liquid petroleum gas (LPG).

[0008] Further possible fuels that can be added upon request are LBG (liquefied biogas), biofuels (such as oils made from algae or seaweed), ammonia, hydrogen, and synthetic fuels from CO2 (made, for example, by Power-To-Gas or Power-To-Liquid).

[0009] Large ships, especially those for transporting goods, are usually powered by internal combustion engines, especially diesel and / or gas engines, mainly two-stroke cross-head engines. In the case of liquid fuels such as heavy fuel oil, marine diesel oil, diesel, or other liquids burned by the engine, and in the case of gaseous fuels such as LNG, LPG, or others, the exhaust from this combustion process needs to be cleaned to comply with existing regulations such as IMO Tier III.

[0010] IMO emission standards, generally referred to as Tier I…III standards, define, among other things, NOx emission standards for existing and new marine engines. x for emissions.

[0011] In the case of large ships, the emission requirements are increasing, especially with regard to nitrogen oxide emissions. Therefore, it is necessary to reduce the amount of nitrogen oxides in the exhaust gas emitted by the internal combustion engines of these ships.

[0012] Nitrogen oxides (NOx) in the exhaust gas of combustion engines xTo reduce the level of [[ID=]], Selective Catalytic Reduction (SCR) technology is used. SCR is commonly used in onshore engines, such as heavy vehicles, industrial plants, and other applications. SCR technology is also used in marine environments in combination with two-stroke diesel engines. Due to regulatory requirements regarding said marine and onshore engines, the need for an efficient SCR system is increasing.

[0013] SCR can be based on reducing nitrogen oxides in the exhaust gas with a reducing agent gas in gaseous form, or in a solution such as an aqueous solution, or a reducing agent such as ammonia (NH3) as urea.

[0014] Normally, ammonia is generated by injecting a liquid reductant agent precursor substance, such as a urea solution, into the exhaust gas of a combustion engine. For example, the urea solution is sprayed into the high-temperature exhaust gas by a nozzle, where the liquid urea solution reacts to form a gaseous reducing agent, namely ammonia, carbon dioxide, and water vapor. The ammonia then reduces the nitrogen oxides to nitrogen (N2) and water (H2O) under the influence of a catalyst in the SCR reactor. The generation of ammonia from liquid urea is endothermic. Therefore, the decomposition of the urea solution is complete and the nitrogen oxides (NO x ) are reduced to nitrogen (N2) only when the exhaust gas is sufficiently hot. As the exhaust gas temperature decreases, the residence time required for sufficient decomposition and mixing with the exhaust gas increases.

[0015] European Patent Application No. 17196592.4, published as European Patent Application Publication No. 3460639(A), which is incorporated by reference, discloses a compact device for generating a reducing agent gas from a solid or liquid reducing agent such as a reductant agent precursor substance. The reductant solution is heated and reacts with the gaseous ammonia injected into the exhaust gas of the combustion engine.

[0016] To operate high-temperature and low-temperature exhaust gases, the combustion engine can have a device for injecting a liquid reductant precursor substance and a device for generating and injecting a reducing agent gas. Preparing two devices requires extra space.

Prior Art Documents

Patent Documents

[0017]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0018] Therefore, an object of the present invention is to prevent the drawbacks of the prior art, and in particular, to minimize the emission of side reaction products such as N2O and SO3 and / or reduce the administration of reducing agents such as ammonia or ammonia precursor substances, to ensure a compact arrangement of the exhaust aftertreatment system and the reactor, and to reduce energy consumption, and to provide a device and method for providing a reducing agent, an exhaust aftertreatment system, and a combustion machine.

Means for Solving the Problems

[0019] This object is achieved by the features of the independent claims.

[0020] The device for providing a reducing agent has at least one reducing agent providing section.

[0021] The reducing agent preferably results in the reduction of pollutants in the exhaust gas of the combustion engine, especially NO x of.

[0022] The reducing agent providing section preferably has at least one reactor for generating a reducing agent gas and / or a heated reducing agent liquid.

[0023] The reactor preferably has a heating system with a heating control unit and a heating element. At least one of the inner volume of the reactor and the contents of the reactor such as a reducing agent and / or a reducing agent precursor substance can be heated.

[0024] The reactor can have a first and a second heating zone. The first and second heating zones each have at least one heating element, and the first and second heating zones can be controllable independently of each other by a heating control unit.

[0025] The heating system is preferably an electric heating system and can have electric heating rods. The heating rods can be U-shaped. The heating rods are advantageous because they can extend through the inner volume and thereby provide a large surface area for heating the inner volume.

[0026] The reactor is preferably adapted to decompose a reducing agent liquid or a reducing agent precursor substance into a reducing agent gas, for example, to decompose urea into a gas mixture containing NH3, CO2, and H2O.

[0027] The heating system can be arranged inside the reactor.

[0028] The reducing agent supply section preferably has a reductant supply unit for the reducing agent liquid.

[0029] The reducing agent liquid can be guided directly from the reductant supply unit to the exhaust gas and / or to the reactor.

[0030] The reductant supply unit can have a reservoir for storing the reducing agent liquid and / or piping for guiding the reducing agent liquid.

[0031] The reductant supply unit and the reactor can be arranged in a common housing or separately.

[0032] Preferably, the supply unit is designed such that the reducing agent is always guided through the reactor. The reducing agent is advanced from the reductant supply unit to the reactor even when the reducing agent liquid is sent to the exhaust gas. The reactor can be heated to evaporate the reducing agent liquid only when required. Preferably, the reactor is heated only when the exhaust gas temperature is low. Therefore, the dimensions of the reactor can be chosen to be as compact as possible. Additional piping from the reductant supply unit to the exhaust is not necessary.

[0033] Preferably, the device does not have a second pipe that communicates from the reductant supply unit to the region between the cylinder and the SCR reactor and bypasses the reactor.

[0034] When the reducing agent liquid is sent directly from the reductant supply unit to the exhaust gas, it is not necessary to advance the entire reducing agent liquid through the reactor. The reactor can be used only when required, preferably only when the exhaust gas temperature is low.

[0035] The device further preferably has a supply system suitable for dispensing a reducing agent gas containing ammonia and a reducing agent liquid preferably having urea.

[0036] The supply system is adjustable to dispense either a reducing agent gas or a reducing agent liquid or both a reducing agent gas and a reducing agent liquid into the exhaust gas.

[0037] In particular, the supply system is adjustable to dispense the reducing agent liquid from the reductant supply unit into the exhaust gas. Preferably, the supply system is adjustable to advance all of the reducing agent through the reactor for dispensing the reducing agent in an evaporated state and a liquid state.

[0038] Alternatively, the supply system can also be adjustable to guide the reducing agent liquid to the exhaust gas without advancing the reducing agent liquid through the reactor.

[0039] Therefore, the supply system can be adjusted to simultaneously dispense the reductant liquid and the reductant gas into the exhaust gas, such that on the one hand, the reductant liquid can be guided to the exhaust gas without advancing it into the reactor, and on the other hand, the reductant can be guided to the reactor and evaporated.

[0040] The supply system can include piping, valves, and pumps and / or nozzles. Thus, the reductant liquid, heated reductant liquid, and / or reductant gas can be supplied by a single device. The heated reductant liquid and the reductant gas can be provided only when needed.

[0041] Typically, when unheated urea is injected into the exhaust gas, the exhaust gas system needs to provide a specific extra space and / or residence time to enable heating and decomposing the urea upstream of the SCR reactor if the exhaust gas is not warm enough to quickly heat the urea. As the exhaust gas temperature decreases, the required residence time for sufficient decomposition and mixing increases.

[0042] Since the reductant can be heated and decomposed by a device, such extra space is not necessary.

[0043] When the engine load is high and the respective exhaust gas temperatures are high, the reductant can be injected directly into the SCR reactor, at least in the immediate vicinity of the SCR reactor upstream of the SCR reactor, without heating.

[0044] When the engine load is low, heated reductant liquid or reductant gas can be provided.

[0045] Thus, the reductant can be prepared in a suitable form within the reductant supply section.

[0046] The device can preferably further include a mixing unit adapted to circulate the reductant within the reactor of the supply section and / or within the reductant supply unit during heating.

[0047] More preferably, the device can have one or more direct or indirect temperature sensors and / or one or more pressure sensors, and the heating control unit is adapted to keep the temperature in the inner volume of the reactor at a preset temperature and / or keep the pressure in the inner volume of the reactor at a preset pressure. Thereby, a certain reaction state is provided.

[0048] The device can have a storage tank for providing a stock of reducing agent liquid, reducing agent solid, reducing agent gas, and / or reducing agent precursor substance.

[0049] The device can thus provide a stock of reducing agent gas and / or heated reducing agent liquid. Additionally or alternatively, the reducing agent gas and / or heated reducing agent liquid can be produced in the reactor as needed.

[0050] In a preferred embodiment, the device can have a plurality of reducing agent providing sections. Thereby, the throughput is increased.

[0051] The device further has a control unit adapted to select an injection mode, where at least a first injection mode corresponds to providing a reducing agent liquid and a second injection mode corresponds to providing a reducing agent gas. The control unit may be adapted to provide a selection of further injection modes, where a reducing agent liquid heated to a selected temperature is dispensed.

[0052] The control unit has at least one input line for receiving an input signal, preferably an input signal from a measuring unit.

[0053] The input signal can also be provided by, for example, an engine control unit to transmit information related to the engine load and / or by an input terminal to enable, for example, a user to give commands.

[0054] The control unit has a processor unit. The control unit has at least one output line, and the output line transmits a control signal to adjust the supply system and / or the reducing agent providing section so as to dispense a reducing agent liquid and / or a reducing agent gas.

[0055] By determining the control signal, each injection mode is selected.

[0056] The control unit can thus adjust the supply system and / or the reducing agent providing section so as to send a reducing agent liquid or a reducing agent gas into the exhaust gas.

[0057] The control unit can be designed to start heating the inner volume and / or the contents of the reactor to provide a reducing agent gas when required, or to guide a reducing agent liquid through an unheated reactor to the exhaust gas.

[0058] For example, at least one output line can set at least one valve so as to enable guiding a reducing agent liquid or a reducing agent gas into the exhaust gas.

[0059] For example, the valve can be set so that a reducing agent liquid is guided through an unheated reactor to the exhaust gas, or so that a reducing agent liquid can be guided directly from the reductant supply unit to the exhaust gas.

[0060] The valve can also be set so as not to allow a reducing agent liquid to be guided directly from the reductant supply unit to the exhaust gas.

[0061] The valve can be set, for example, so that a reducing agent liquid is guided through a reactor without being heated to at least one nozzle for sending the reducing agent liquid into the exhaust gas.

[0062] The valve can be set such that the reducing agent liquid is guided through the heated reactor, and thus the reducing agent gas is guided to at least one nozzle for sending the reducing agent gas into the exhaust gas.

[0063] Preferably, the output line is connected or connectable to the heating control unit of the heating system of the device. The control unit can thus initiate the heating of the inner volume and / or the contents of the reactor, for example, to provide the heated reducing agent liquid and / or the reducing agent gas when required.

[0064] The control unit can operate according to a certain operating procedure and provide control signals according to a predetermined scheme.

[0065] The control unit can provide control signals for setting the valves and pumps of the supply system and / or the reducing agent supply section so that the reducing agent gas is provided, for example, during the first stage of operation when the engine load is usually low.

[0066] In the second operating stage when the engine load increases, the control signal can be changed to set the valves and pumps of the supply system and / or the reducing agent supply section so that the reducing agent liquid is provided.

[0067] The control unit can have an input device, and by means of the input device, the user can set the operating mode to control the output line.

[0068] In an advanced embodiment of the device, the control unit is configured to provide at least one control signal in response to at least one input signal. The control unit can have a processor.

[0069] The control unit can use a look-up table or a processing scheme to determine the control signal in response to at least one input signal.

[0070] In a preferred embodiment, the device has at least one sensor for measuring at least one operating parameter.

[0071] Preferably, the device is a device as described above, and the sensor is connected or connectable to an input line of the control unit or to a sensor signal output line that is connected or connectable.

[0072] The operating parameter measured by the sensor can thus be used by the control unit as an input signal.

[0073] The sensor can be, for example, a temperature sensor for measuring the temperature of the exhaust gas, especially upstream and / or downstream of the SCR reactor.

[0074] Alternatively or additionally, the device can have sensors for measuring further operating parameters, the pressure in the cylinder, the pressure of the exhaust gas, the temperature difference of the exhaust gas upstream and downstream of the SCR reactor, and / or the components of the exhaust gas.

[0075] The input signal can also be provided, for example, by the engine control unit for transmitting information regarding the engine load and / or by the input terminal for enabling the user to give commands, for example.

[0076] The reducing agent supply section can have at least one dosing unit for adjusting the amount of reducing agent to be dispensed.

[0077] The dosing unit can have an input line that is connected or connectable to an output line of the control unit for receiving a control signal transmitted by the control unit.

[0078] Thus, the control unit can not only function to determine the state of the reducing agent, such as liquid or gaseous, and the temperature of the reducing agent, but the control unit can also determine a control signal for adjusting the amount of reducing agent dispensed into the exhaust gas.

[0079] The dosing unit can have one dosing pump or two or more dosing pumps and / or one or two or more pumps with dosing valves. Thereby, the outflow that sends the reducing agent gas and / or the reducing agent liquid and / or the heated reducing agent liquid into the exhaust gas, and / or the outflow that sends the reducing agent liquid from the reductant supply unit to the reactor can be controlled.

[0080] The device can have a first dosing unit for setting the flow through and from the reductant supply unit, and a second dosing unit for setting the flow through and from the reactor.

[0081] The device can have at least one pre-reactor for generating the reducing agent liquid from the solid reducing agent.

[0082] Solid reducing agents are generally easier to handle on board. Transport and storage can be managed with less effort.

[0083] In particular, solid urea is advantageous because it is a stable non-volatile material that can be stored, transported, and handled safely. Furthermore, solid urea is available at low cost.

[0084] The water used for mixing can be from the water separator of the marine vessel. The device can include a filter for filtering the water from the water separator.

[0085] The pre-reactor can have a mixing unit and a heating unit.

[0086] By heating, a higher concentration is achieved in the reducing agent liquid.

[0087] Preferably, the pre-reactor is incorporated within the reducing agent providing section. The pre-reactor may be disposed within a housing common to the reactor or may be disposed separately.

[0088] The pre-reactor may be disposed upstream of the reactor.

[0089] The pre-reactor may be part of the reductant supply unit.

[0090] The pre-reactor can be disposed upstream of the reductant supply unit for the reducing agent liquid, and the reducing agent liquid produced within the pre-reactor can be guided to the piping or reservoir of the reductant supply unit.

[0091] Additionally or alternatively, the pre-reactor can provide a reservoir for the reducing agent liquid.

[0092] The pre-reactor can provide a reducing agent liquid that can be directly guided to the exhaust gas when the pre-reactor is part of the reductant supply unit. Alternatively, the pre-reactor can provide a reducing agent liquid that can be guided to or advanced to the reductant supply unit.

[0093] The pre-reactor can provide a reducing agent liquid that can be advanced to the exhaust gas via the reducing agent providing section, particularly via the reactor.

[0094] Alternatively, the first pre-reactor can provide a reducing agent liquid that can be directly guided to the exhaust gas or guided via the reductant supply unit. The second pre-reactor can provide a reducing agent liquid that is guided to the reactor.

[0095] In a preferred embodiment of the device, the supply system has a first pipe for guiding the reducing agent liquid and / or the reducing agent gas from the reducing agent providing section to the exhaust gas. Preferably, the supply system has a pipe heating device, for example, equipped with a heating element.

[0096] The first pipe can be arranged downstream of the reactor.

[0097] Additionally, the device can have a second pipe for guiding the reducing agent liquid from the reducing agent supply section to the exhaust gas.

[0098] The second pipe can be arranged downstream of the reductant supply unit for the reducing agent liquid.

[0099] The second pipe enables the reducing agent liquid to be directly guided to the exhaust gas without entering the reactor.

[0100] The control unit can be adapted to select an injection mode, where the reducing agent liquid and the reducing agent gas are simultaneously dispensed into the exhaust gas. The reducing agent liquid can be guided through the second pipe, while the reducing agent gas can be guided through the first pipe.

[0101] The first pipe can have a diameter of 10 - 50 mm and can be pressure-resistant up to 80 bar, preferably up to 2 - 50 bar, more preferably up to 2 - 40 bar. The first pipe is preferably a double-walled pipe.

[0102] The second pipe can have a diameter of 5 - 30 mm.

[0103] The first pipe and the second pipe can preferably merge within a third pipe or a nozzle upstream of the SCR reactor.

[0104] Alternatively, the first pipe and the second pipe do not merge until they lead into the exhaust gas system and remain separate pipes.

[0105] The supply system can be arranged to guide the reducing agent liquid within the region downstream of the cylinder and upstream of the SCR reactor. In particular, the second pipe can be arranged to guide the reducing agent liquid into the exhaust gas system upstream of the SCR reactor, such as an exhaust gas manifold.

[0106] The supply system can be arranged to guide the reducing agent gas directly to the SCR reactor or to the region immediately upstream of the SCR reactor. In particular, the first pipe can be arranged to guide the reducing agent gas directly to the SCR reactor or near the upstream of the SCR reactor.

[0107] The first pipe can lead to the inlet of the SCR reactor.

[0108] The first pipe can be connected to at least one nozzle for sending the reducing agent liquid into the exhaust gas and at least one nozzle for sending the reducing agent gas into the exhaust gas.

[0109] The first pipe can have at least one valve, preferably two valves. The first pipe can have one valve for opening and closing the connection to at least one nozzle for sending the reducing agent liquid into the exhaust gas and one valve for opening and closing the connection to at least one nozzle for sending the reducing agent gas into the exhaust gas.

[0110] Generally, the nozzle for sending the reducing agent liquid has a smaller total outlet area than the nozzle for sending the reducing agent gas.

[0111] In an alternative embodiment, the first and / or second pipe is arranged to guide the reducing agent to the exhaust gas system upstream of the SCR reactor. In a preferred embodiment, the supply system has a two-fluid injection nozzle for delivering the reducing agent liquid.

[0112] The nozzle can preferably have at least one inlet for fluid connected to a liquid pipe and / or a liquid reductant supply unit, and at least one inlet for gas connected to a gas pipe and / or a gas reservoir, in particular an air supply unit for providing pressurized air.

[0113] Pressurized air can be mixed with the reductant liquid inside the nozzle, whereby the reductant liquid is sprayed out of the nozzle and finely and evenly distributed.

[0114] The nozzle can be connected to a pipe for guiding the reductant liquid, preferably to a first pipe and / or a second pipe for guiding the reductant liquid.

[0115] In a preferred embodiment, the supply system has a two-state injection nozzle for delivering both the reductant liquid and the reductant gas through the same nozzle and in their respective appropriate states. The two-state injection nozzle can be connected to a first pipe for supplying the reductant liquid or the reductant gas.

[0116] This object is also preferably achieved by a device for delivering a reductant for reducing pollutants, in particular NO x in the exhaust gas of a combustion engine, and this device has at least one reductant-providing section and preferably has a supply system suitable for dispensing a reductant gas containing ammonia and a reductant liquid preferably having urea into the exhaust gas. The device further has at least one two-state nozzle for delivering both the reductant liquid and the reductant gas.

[0117] The reductant-providing section has a reductant supply unit for the reductant liquid and at least one reactor, and the reactor has a heating system with a heating control unit and a heating element for heating at least the inner volume and / or the contents of the reactor.

[0118] The device can have only a first pipe for guiding the reducing agent liquid and / or the reducing agent gas from the reactor to the area between the cylinder and the SRC reactor. The device can additionally have a second pipe for guiding the reducing agent liquid from the reductant supply unit to the area between the cylinder and the SRC reactor and bypassing the reactor. The first pipe and ultimately the second pipe can be or can be connected to a two-state injection nozzle.

[0119] The nozzle can have a further opening for dispensing only the reducing agent gas. The nozzle can have, for example, a switch having valves for guiding the reducing agent to their respective outlets.

[0120] The two-state injection nozzle can be switchable between a first state in which the two-state injection nozzle can have at least one opening having a first total opening area for the reducing agent liquid to exit to the outside, and a second state in which the two-state injection nozzle can have at least one opening having a second total opening area for the reducing agent gas to exit to the outside.

[0121] The second total opening area is larger than the first total opening area.

[0122] The total opening area can be the sum of the opening areas of a plurality of openings.

[0123] In the first state, the two-state injection nozzle can have at least one further outlet for the pressurized gas to exit to the outside for spraying the reducing agent liquid.

[0124] The two-state nozzle preferably has at least one movable element, such as a movable inner pipe member or a movable closing element. When the movable element is in a first position, the two-state nozzle is in a first state for dispensing the reducing agent liquid, and when the movable element is in a second position different from the first position, the two-state nozzle is in a second state for dispensing the reducing agent gas.

[0125] The supply system can have an air supply unit, and the air supply unit can be connected to or connectable to the first pipe and / or the second pipe and / or the two-component injection nozzle and / or the two-state injection nozzle.

[0126] The air supply unit is preferably arranged upstream of the two-component injection nozzle or upstream of the two-state injection nozzle.

[0127] The air supply unit can provide pressurized air to the pipes and / or nozzles for spraying the reducing agent liquid into the exhaust gas.

[0128] The air supply unit can alternatively or additionally be connectable to the reactor and the reductant supply unit for the reducing agent liquid. When the operation of the engine is interrupted, the air supply can be used to clean all the pipes of the reactor and / or the reductant supply unit and the supply system and the reducing agent providing section. Thus, if there are residues of the reducing agent that may be toxic and unwanted residues, these can be removed.

[0129] The supply system can have a gas and / or vapor administration unit. The gas and / or vapor administration unit is preferably arranged downstream of the reactor. The gas and / or vapor administration unit can be adapted to limit or adjust the pressure in the reactor and / or the pressure of the reducing agent gas leaving the reactor.

[0130] The device can have pipe heating for the first pipe, the second pipe, and / or the third pipe. The pipe heating can heat the pipes to 50°C, 60°C, 70°C, 80°C, 130°C, or 145°C. By heating the pipes, the energy consumption of the reactor is reduced, and a higher concentration of the reducing agent can be transported through the pipes without damaging the pipes.

[0131] When the pipes are heated, for example, the urea solution can have a maximum of 77% by weight of urea. Alternatively, the urea solution can have only 40% by weight of urea.

[0132] In the heated pipe, the risk of forming condensate or any other unwanted deposits is reduced.

[0133] The device can have a high-pressure and / or high-temperature vessel. Preferably, the reactor is arranged within a high-pressure and / or high-temperature vessel. The reaction and decomposition occur faster at higher temperatures.

[0134] The vessel can be adapted to a pressure of up to 80 bar, preferably from 2 to 50 bar, more preferably from 2 to 40 bar, and / or a temperature of up to 300 °C.

[0135] The vessel can have an inner volume of less than 3200 liters, preferably less than 1600 liters, particularly preferably less than 200, 120, or 60 liters. Thereby, a lightweight and compact device is provided. Such a device can be advantageous in applications where space is limited, such as marine applications.

[0136] This object is also achieved by an exhaust aftertreatment system having a device as described above and a selective catalytic reduction (SCR) reactor.

[0137] This object is also achieved by a large marine engine having a combustion engine, preferably a two-stroke engine having at least one cylinder, preferably at least one cylinder having an inner diameter of at least 200 mm, and a device as described above or an exhaust aftertreatment system as described above.

[0138] This object is also achieved by a method for delivering a reducing agent, preferably for reducing pollutants, in particular NO x in the exhaust gas of a combustion engine. The reducing agent is preferably provided within a device as described above.

[0139] The method preferably has a supply system suitable for dispensing a reducing agent gas containing ammonia and / or a reducing agent liquid having urea, and / or adjusts a reducing agent providing section to dispense a reducing agent gas containing ammonia and / or a reducing agent liquid having urea.

[0140] The adjustment of the supply system and / or the reducing agent providing section can include setting at least one dosing pump, setting at least one dosing valve, providing an appropriate amount or rate of the reducing agent liquid, providing an appropriate amount or rate of the heated reducing agent liquid, providing an appropriate amount or rate of the reducing agent gas, and / or heating the reducing agent liquid.

[0141] In a subsequent step, the reducing agent gas and / or the reducing agent liquid is dispensed by the supply system from the reducing agent providing section into the exhaust gas. Preferably, the reducing agent gas and / or the reducing agent liquid is dispensed from a heatable reactor.

[0142] Preferably, in order to adjust the supply system, an injection mode is preferably selected by a control unit.

[0143] After selection of the first injection mode, the supply system and / or the reducing agent providing section is adjusted to provide the reducing agent liquid.

[0144] After selection of the second injection mode, the supply system and / or the reducing agent providing section is adjusted to provide the reducing agent gas.

[0145] Preferably, after selection of the third injection mode, the supply system and / or the reducing agent providing section is prepared to provide the heated reducing agent liquid.

[0146] Each reducing agent is provided within the reducing agent providing section and guided into the exhaust gas of the combustion machine.

[0147] After selecting each injection mode, the reducing agent liquid can be heated within the reducing agent providing section, thereby providing the heated reducing agent liquid and / or reducing agent gas.

[0148] In a device having a first pipe and a second pipe as described above, another fourth injection mode can preferably be selected by a control unit. After selecting the fourth injection mode, the supply system and / or the reducing agent providing section are adjusted to simultaneously provide the reducing agent gas and the reducing agent liquid.

[0149] At least one operating parameter, in particular the temperature of the exhaust gas, the engine power and / or the engine load, can be checked, and the selection can be made according to at least one operating parameter.

[0150] In a preceding step, the reducing agent solution can be mixed by dissolving a solid reducing agent in water in the mixing tank of the pre-reactor.

[0151] Preferably, the solution is preheated.

[0152] The reducing agent solution is preferably guided, in particular pumped, through an inlet pipe, preferably through a heated pipe, from the mixing tank to the reductant supply unit and / or the reactor of the reducing agent providing section.

[0153] Alternatively, the reducing agent solution can be mixed in the reductant supply unit of the reducing agent providing section.

[0154] A further advantageous aspect of the invention is explained below by way of exemplary embodiments and figures.

Brief Description of the Drawings

[0155]

Figure 1

Figure 2

Figure 3a

Figure 3b

Figure 4a

Figure 4b

[0156] FIG. 1 shows a schematic diagram of a first example of a combustion machine 100 including a cylinder 32 and an exhaust aftertreatment system 33 having an SCR reactor 30 and a device 1 for providing a reducing agent.

[0157] The reducing agent can reduce pollutants, particularly NO x in the exhaust gas of the combustion engine 10.

[0158] The device 1 has at least one reducing agent providing section 2 including a reactor 3b and a reductant supply unit 3a.

[0159] The reductant supply unit 3a can receive a stock of the reductant liquid.

[0160] The device 1 has a heating system 4 including a heating control unit 5 and a heating element 6 for heating the inner volume and / or the contents 7 of the reactor 3b.

[0161] The reactor 3b can receive the reductant liquid from the reductant supply unit 3a, and the reductant liquid can become a heated reductant liquid after heating or can be decomposed into a reductant gas. The reactor 3b is disposed within a high-pressure and high-temperature container 24.

[0162] The device 1 preferably has a supply system 8 suitable for dispensing a reductant gas preferably containing ammonia and a reductant liquid preferably having urea.

[0163] The supply system 8 dispenses a reducing agent gas and / or a reducing agent liquid to the exhaust gas away from the cylinder 32 of the engine 10 according to the selection by the control unit 11.

[0164] The supply system 8 has a two-fluid injection nozzle 9. The nozzle 9 is connected to a reductant supply unit 3a and an air supply unit 19 for providing pressurized air. Therefore, the reducing agent liquid is guided from the reductant supply unit 3a to the nozzle 9 through the second pipe 17 and can be sprayed into the region 31 upstream of the SCR reactor 30 by the pressurized air supplied by the air supply unit 19.

[0165] The reducing agent gas generated in the reactor 3b can be guided through the first pipe 18 to the region 31 between the cylinder 32 and the SCR reactor 30, directly to the SCR reactor 30, or near the SCR reactor 30.

[0166] When the reducing agent liquid is dispensed into the region 31 between the cylinder 32 and the SCR reactor 30, the reducing agent liquid takes time to decompose. When the exhaust temperature is low, more time is required.

[0167] When the engine 32 operates at high load and the exhaust gas temperature is high, the reducing agent liquid can be dispensed upstream and near the SCR reactor 30. The reason is that the liquid decomposes quickly by the high-temperature exhaust gas.

[0168] As the temperature of the exhaust gas decreases, the decomposition of the low-temperature reducing agent liquid becomes more time-consuming. Therefore, a longer flow path is required for the liquid to decompose before reaching the SCR reactor. However, in the device of the present invention, when the exhaust temperature decreases, the heated reducing agent liquid can be injected, thereby decomposing more quickly and not requiring extra space for decomposition.

[0169] Even when the temperature of the exhaust gas is low, the reducing agent gas can be dispensed, and thus no space for decomposition is required. Therefore, the space upstream of the SCR reactor can be minimized.

[0170] In any case, the reducing agent gas can be dispensed very close to the SCR reactor.

[0171] Therefore, the distance between the cylinder 32 and the SCR reactor 30 can be designed with a relatively small size.

[0172] The gas and / or vapor dosing unit 20 is arranged downstream of the reactor 3b. The gas and / or vapor dosing unit can adjust the pressure and / or temperature of the reducing agent gas leaving the reactor 3b via the first pipe 18.

[0173] The device 1 has a control unit 11.

[0174] The control unit 11 has an input line 12 for receiving at least one input signal from the measurement unit 13.

[0175] The control unit 11 has a processor unit 14 and an output line 15 for transmitting at least one control signal for adjusting the reducing agent supply section 2.

[0176] The output line 15 is connected to the heating control unit 5 of the heating system 4 of the reactor 3b.

[0177] Device 1 has a dosing unit 23 for setting pumps and / or valves (not explicitly shown in the figure) that enable guiding each reducing agent to an area 31 upstream of the SCR reactor 30 of the engine 10. The dosing unit 23 can, for example, set a valve to enable guiding the reducing agent liquid into the reactor 3b to heat and / or evaporate it, or can set the valve to enable directly guiding the reducing agent liquid from the reductant supply unit 3a to the area 31 upstream of the SCR reactor 30.

[0178] The dosing unit 23 can also set pumps and / or valves to determine the total amount of the total flow rate of the reducing agent dispensed into the exhaust gas.

[0179] A further output line 15b is connected to the dosing unit 23.

[0180] In response to at least one input signal received from the sensor 13 via the input line 12, the control unit 11 is configured to provide at least one control signal to the output lines 15, 15b.

[0181] Device 1 has a pre-reactor 16 for generating a reducing agent liquid from a solid reducing agent. The pre-reactor 16 can be incorporated into the reductant supply section 2. In this example, the pre-reactor 16 is arranged separately upstream of the reductant supply unit 3a.

[0182] FIG. 2 shows a schematic diagram of a second example of a combustion machine 100 having a cylinder 32, an SCR reactor 30, and an exhaust aftertreatment system 33 having a device 1 for providing a reducing agent, similar to the example shown in FIG. 1.

[0183] Device 1 has a reductant supply section 2 with a reductant supply unit 3a and a heatable reactor 3b.

[0184] The reactor 3b receives the reducing agent liquid from the reductant supply unit 3a.

[0185] Depending on the signal received on output line 15 from control unit 11, the reducing agent liquid is heated and reducing agent gas is produced, or the reducing agent liquid is guided through reactor 3b without being heated.

[0186] Device 1 preferably has a supply system 8 suitable for dispensing a reducing agent gas preferably containing ammonia and a reducing agent liquid preferably having urea.

[0187] Supply system 8 dispenses reducing agent gas and / or reducing agent liquid into the exhaust gas leaving cylinder 32 of engine 10, depending on the selection by control unit 11.

[0188] Supply system 8 has a first pipe 18 connected to a two-fluid injection nozzle 9 and a gas nozzle 35.

[0189] When the reducing agent liquid is guided into first pipe 18 through the reactor, valve 34a receives a signal from control unit 11 via output line 15c and opens, whereby the reducing agent liquid is sent to the exhaust gas by two-fluid injection nozzle 9. At the same time, valve 34b receives a signal from control unit 11 via output line 15d and closes.

[0190] Two-fluid injection nozzle 9 is connected to an air supply unit 19 for providing pressurized air. Thus, the reducing agent liquid can be sprayed.

[0191] A further valve 34c (see Figure 3a) can be arranged between air supply unit 19 and two-fluid injection nozzle 9. Valve 34c and / or air supply unit 19 can be connected to a further output line (not shown in the figure) connected to control unit 11 to cause the supply of pressurized air when required.

[0192] When a reducing agent gas is generated in the reactor and guided into the first pipe 18, the valve 34b is opened by obtaining a signal from the control unit 11 via the output line 15d, whereby the reducing agent gas is sent to the exhaust gas by the gas nozzle 35. At the same time, the valve 34a is closed by obtaining a signal from the control unit 11 via the output line 15d.

[0193] Therefore, only one pipe 18 is required to guide the reducing agent liquid and the reducing agent gas from the reducing agent supply unit 3a to the region 31 upstream of the SCR reactor 30.

[0194] Alternatively, unlike the examples shown in FIGS. 1 and 2, the reducing agent liquid and the reducing agent gas can be guided to the region 31 upstream of the SCR reactor 30 and into the exhaust by the same two-state injection nozzles 35, 50 (see FIGS. 3a, 3b, 4a, and 4b).

[0195] FIG. 3a shows a schematic view of a first example of a two-state injection nozzle 35 in a first state in which the reducing agent liquid can be sprayed.

[0196] The two-state injection nozzle 35 has a nozzle housing 36 having an opening 37. The two-fluid injection nozzle 35 further has an inner pipe member 38 fluidly connected to the first pipe 18.

[0197] The inner pipe member 38 is movable along the longitudinal axis 39 of the two-fluid injection nozzle 35.

[0198] The inner pipe member 38 can be fluidly connected to the first pipe 18 by a telescopic connection (not shown in detail) or by a flexible pipe.

[0199] At the axial end 42 facing outward from the first pipe 18, the inner pipe member 38 has a narrow opening 43. The diameter 44 of the opening 43 is smaller than the open diameter 45 of the first pipe 18.

[0200] The two-state injection nozzle 35 can have an actuation system (not shown in the figures) for axially moving the inner pipe member 38. The actuation system can be a magnetic, mechanical, pneumatic, hydraulic or electrical system, and / or can have magnetic and / or electrical and / or pneumatic and / or hydraulic switches and / or motors.

[0201] The inner pipe member 38 is supported by a support member 40. In this case, the support member 40 is an annular member provided with a through hole 41.

[0202] Alternatively, the support member 40 (not shown in the figures) can have circumferentially arranged and circumferentially spaced posts.

[0203] The annular space 47 between the inner pipe member 38 and the nozzle housing 36 can be connected to the air supply unit 19 by a valve 34c.

[0204] In the first state, the axial end 42 of the inner pipe member 38 is positioned near, preferably inside, the opening 37 of the nozzle housing 36 to form a slit 48 between the axial end 42 of the inner pipe member 38 and the nozzle housing.

[0205] The inner pipe member 38 is positioned such that a radially facing hole 46 in the inner pipe member 38 is closed by the support member 40.

[0206] The reducing agent liquid can be guided into the inner pipe member 38 through the first pipe 18. Pressurized air can be guided from the air supply unit 19 into the nozzle housing through the open valve 34c, proceed through the through hole 41 of the support member 40, and exit from the two-fluid injection nozzle 35 through the slit 48.

[0207] The pressurized air causes the reducing agent liquid leaving the inner pipe member 38 to be atomized through the narrow hole 43.

[0208] Figure 3b shows a schematic view of a first example of the two-state injection nozzle 35 in a second state in which the reducing agent gas can be dispensed.

[0209] The valve 34c (see FIG. 3a) is closed.

[0210] The inner pipe member 38 is moved to a position where the axial end portion 42 is disposed at a distance 48 from the opening 37 of the nozzle housing 36.

[0211] The radially facing holes 46 are here opened towards the annular space 48.

[0212] The reducing agent gas guided to the two-fluid injection nozzle 35 by the first pipe 18 (see FIG. 3a) can flow through the radially facing holes 46, through the through holes 41, through the narrow holes 43, and out into the housing 36, from where it can leave through the opening 37 and reach the exhaust gas.

[0213] In the first state, the two-state injection nozzle 35 provides two small separate outlet openings, namely the slit 48 for guiding the pressurized gas and the narrow opening 43 for discharging the reducing agent liquid to the outside. The reducing agent liquid can be sprayed into the exhaust gas.

[0214] In the second state, the two-state injection nozzle 35 provides a larger opening area, namely the total area of the opening 37 of the housing 36. The larger opening area is necessary because a specific amount of the gaseous-phase reducing agent has a larger volume than the liquid phase. Therefore, a higher throughput is required.

[0215] In an alternative embodiment not shown in the figures, the nozzle housing 36 can be movable relative to the inner pipe member 38.

[0216] FIG. 4a shows a schematic view of a second example of the two-state injection nozzle 50 in the first state. FIG. 4b shows a detailed schematic view of the second example of the two-state injection nozzle 50 in the second state.

[0217] The two-state injection nozzle 50 has an inner pipe 51 that is connected to or connectable to the first pipe 19, and an outer pipe 52 arranged coaxially with the inner pipe 51.

[0218] The annular space 53 between the inner pipe 51 and the outer pipe 52 can be connected to the air supply unit 19 by the valve 34c.

[0219] At the end 53 facing outward from the first pipe 18, the inner pipe 51 has a narrow opening 54. The diameter 55 of the opening 54 is smaller than the open diameter 45 of the first pipe 18.

[0220] The end 53 of the inner pipe 51 and the end 56 of the outer pipe 52 limit the slit opening 57. Preferably, the inner pipe 51 and the outer pipe 52 taper towards their respective ends 53, 56.

[0221] The inner pipe 51 has at least one radially facing opening 58 that is radially aligned with at least one radially facing opening 59 of the outer pipe 52. Preferably, all the radially facing openings 58 are aligned with all the radially facing openings 59.

[0222] A closing element 60 is arranged in the annular space 53 between the inner pipe 51 and the outer pipe 52.

[0223] The closing element 60 is movable along the inner pipe 51 and the outer pipe 52 and is supported by a spring 61. The closing element 60 has at least one radially extending opening 62.

[0224] When the spring 61 has no tension, the radially extending opening 62 is aligned with the radially facing opening 58 of the inner pipe 51 and the radially facing opening 59 of the outer pipe 52 to form a radial outlet 63 as shown in Fig. 4b. Preferably, a plurality of radial outlets 63 are formed.

[0225] The reducing agent gas supplied by the first pipe 18 can leave the inner pipe 51 of the two-state injection nozzle 50 through the narrow opening 54 (see Fig. 4a) and through the radially facing openings 58, the radially extending opening 62, and the radial outlet 63 formed by the radially facing opening 58.

[0226] When the reducing agent liquid is supplied by the first pipe 18, the valve 34 is opened and pressurized air flows inwards. The closing element 60 is pressed against the spring 61 in the direction in which the pressurized air flows out (downward in Fig. 4a). The radially facing opening 58 of the inner pipe 51 is closed as shown in Fig. 4a, so that only the reducing agent liquid can leave the two-state injection nozzle 50 through the narrow opening 54.

[0227] The closing element 60 has a longitudinally extending hole. This is along the longitudinal extensions of the inner pipe 51 and the outer pipe 52. The pressurized air can flow through these holes (not shown in the figure) towards the slit opening 57 and spray the reducing agent liquid leaving through the narrow opening 54.

[0228] When the pressurized air is supplied at a pressure of usually 4 to 8 bar, the pressurized air can move the closing element 60 and flow through the longitudinally extending hole in the closing element.

[0229] A second example of the two-state injection nozzle 50 in the first state also provides two small separate outlet openings, namely the slit opening 57 for guiding the pressurized gas and the narrow opening 53 for letting out the reducing agent liquid. The reducing agent liquid can be sprayed into the exhaust gas.

[0230] In the second state, the two-state injection nozzle 50 provides a larger total opening area, namely the sum of the area of the narrow opening 53 and the diameter of the outlet 63 formed by the radially facing opening 58, the radially extending opening 62, and the radially facing opening 59.

[0231] Alternatively, instead of the longitudinally movable closure element 60, a rotatable perforated element (not shown in the figures) can be arranged around the inner tube 51, thereby enabling the opening and closing of the radially facing openings 58, 59.

[0232] In a further alternative embodiment not shown in the figures, a part of the inner tube 51 and / or the outer tube 52 can be movable axially or circumferentially so as to open and close the radially facing openings 58, 59.

Claims

1. A device (1) for delivering a reducing agent for reducing pollutants in the exhaust gas of a combustion engine (10), said device (1) having at least one reducing agent providing section (2), said at least one reducing agent providing section (2) having at least one reactor (3b), said at least one reactor (3b) having a heating system (4), said heating system (4) comprising a heating control unit (5) and a heating element (6) for heating at least the inner volume and / or the content (7) of said reactor (3b), for providing a reducing agent gas as required, and for providing a heated reducing agent liquid as required, and said at least one reducing agent providing section (2) having a reductant supply unit (3a) for the reducing agent liquid, said device (1) further having a supply system (8), said supply system (8) being suitable for dispensing said reducing agent gas, said heated reducing agent liquid, and said reducing agent liquid into said exhaust gas, in the device (1), said device (1) having a control unit (11) adapted to select an injection mode, with at least a first injection mode corresponding to providing said reducing agent liquid, a second injection mode corresponding to providing said reducing agent gas, and a third injection mode corresponding to dispensing said heated reducing agent liquid heated to a selected temperature, said control unit (11) having at least one input line (12) for receiving at least one input signal, said control unit (11) having a processor unit (14), said control unit (11) having at least one output line (15, 15b, 15c, 15d) for transmitting at least one control signal for adjusting said supply system (8) and / or said reducing agent providing section (2) so as to dispense said reducing agent liquid and / or said reducing agent gas and / or said heated reducing agent liquid heated to a selected temperature, The supply system (8) has a first pipe (18) arranged downstream of the reactor (3b) for guiding the reducing agent liquid and the reducing agent gas from the reactor to the exhaust gas, and at least one of the at least one output line (15) is connected to, or connectable to, the heating control unit (5) of the heating system (4) of the reactor (3b), and also the control unit is designed to start heating the inner volume and / or the contents of the reactor to provide the reducing agent gas as needed, or designed to guide the reducing agent liquid through a non-heated reactor to the exhaust gas Device (1), characterized in that it is Device (1). **Claim 2** The supply system (8) has a second pipe (17) for guiding the reducing agent liquid from the reducing agent providing section (2) to the exhaust gas, and also The supply system is adjustable to directly dispense the reducing agent liquid from the reductant supply unit to the exhaust gas without passing through the reactor, according to claim 1 of the device. **Claim 3** The control unit (11) is configured to provide the at least one control signal according to the at least one input signal, according to claim 1 or 2 of the device. **Claim 4** The device (1) has at least one sensor (13) for measuring at least one operating parameter, according to claim 1 or 2 of the device. **Claim 5** The device has at least one dosing unit (23) for adjusting the amount of the reducing agent to be dispensed, according to claim 1 or 2 of the device. **Claim 6** The device (1) has a pre-reactor (16) for generating the reducing agent liquid from a solid reducing agent, according to claim 1 or 2 of the device. **Claim 7** The supply system (8) has a pipe heating device, according to claim 1 or 2 of the device. **Claim 8** The supply system (8) is arranged to guide the reducing agent liquid into the region (31) between the cylinder (32) and the selective catalytic reduction (SCR) reactor (30), and / or The supply system (8) is arranged to guide the reducing agent gas directly to, or in the immediate vicinity of, the selective catalytic reduction (SCR) reactor, according to claim 1 or 2 of the device. **Claim 9** The supply system (8) has an air supply unit (19) and / or The device according to claim 1 or 2, wherein the supply system (8) has a gas and / or steam administration unit (20).

10. The device (1) according to claim 1 or 2 for delivering the reducing agent for reducing the pollutants in the exhaust gas of the combustion engine (10), The device has at least one two-state injection nozzle (35, 50) for delivering both the reducing agent liquid and the reducing agent gas, The two-state injection nozzle (35, 50) has at least one movable element (38, 60), whereby when the movable element (38, 60) is in a first position, the two-state injection nozzle (35, 50) is in a state for dispensing the reducing agent liquid, and when the movable element (38, 60) is in a second position different from the first position, the two-state injection nozzle (35, 50) is in a state for dispensing the reducing agent gas Device (1), characterized in that.

11. An exhaust aftertreatment system having the device (1) according to claim 1 or 2 and a selective catalytic reduction (SCR) reactor (30).

12. A two-stroke large marine engine having at least one cylinder with an inner diameter of at least 200 mm and the device (1) according to claim 1 or 2.

13. In the device (1) according to claim 1 or 2, a method for delivering a reducing agent for reducing pollutants in the exhaust gas of a combustion engine (10), Adjusting the supply system (8) and / or the reducing agent providing section (2) to dispense a reducing agent gas, or a reducing agent liquid, or a reducing agent gas and a reducing agent liquid; Dispensing the reducing agent gas and / or the reducing agent liquid from the reducing agent providing section (2) and the heatable reactor (3b) to the exhaust gas by the supply system (8) and further The method further includes a step of selecting, by the control unit (11), to be in an injection mode, After selecting the first injection mode, the supply system (8) and / or the reducing agent providing section (2) are adjusted to provide the reducing agent liquid, After selecting the second injection mode, the supply system (8) and / or the reducing agent providing section (2) are adjusted to provide the reducing agent gas, After selection of the third injection mode, the supply system (8) and / or the reducing agent providing section (2) are adjusted to provide a heated reducing agent liquid, and each of the reducing agents is guided into the exhaust gas of the combustion engine, Method.

14. The method has a step of selecting an injection mode by a control unit (11), The method according to claim 13 for delivering the reducing agent in the device (1) according to claim 1 or 2, wherein after selection of the fourth injection mode, the supply system (8) and / or the reducing agent providing section (2) are adjusted to provide the reducing agent gas and the reducing agent liquid.

15. The method according to claim 14, wherein at least one operating parameter is determined and the step of selecting the injection mode is based on the at least one operating parameter.

16. The method according to claim 15, wherein the operating parameter includes at least one of the temperature of the exhaust gas, the engine power, and the engine load.

17. mixing the reducing agent solution by dissolving a solid reducing agent in water in a mixing tank (21) of a pre-reactor (16); guiding the reducing agent solution from the mixing tank (21) through an inlet pipe (22) to a reductant supply unit for the reducing agent (3a) liquid and / or the reactor (3b) of the reducing agent providing section (2); and The method according to claim 13, further comprising:

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