Ammonia diesel dual-fuel engine tail gas treatment device

Abstract

The invention discloses an ammonia-diesel dual-fuel engine tail gas treatment device, and relates to the technical field of tail gas treatment, the device comprises an exhaust collecting pipe, selective catalytic reduction equipment, a water spray tower, an ammonia water storage pool, an ammonia water sensor, an ammonia water injection pump, an ammonia water nozzle and a controller; tail gas generated by the ammonia-diesel dual-fuel engine is sequentially guided into the selective catalytic reduction equipment and the water spray tower by the exhaust header and then is exhausted to the atmosphere; the water spray tower is used for spraying an ammonia water solution from top to bottom, and the ammonia water solution is used for adsorbing ammonia gas in the tail gas; the ammonia water sensor detects the mass concentration of ammonia in the ammonia water solution in the ammonia water storage pool; and the controller adjusts the combustion efficiency of the ammonia-diesel dual-fuel engine according to the mass concentration, supplements ammonia water in the selective catalytic reduction equipment, and controls tail gas emission of the ammonia-diesel dual-fuel engine and the water spray tower when the mass concentration is smaller than a first set concentration value. According to the ammonia-diesel dual-fuel engine, emission of unburned ammonia and nitric oxide can be reduced, and the thermal efficiency of the ammonia-diesel dual-fuel engine is improved.

Description

Technical Field

[0001] The present application relates to the technical field of exhaust gas treatment, and in particular to an exhaust gas treatment device for an ammonia-diesel dual-fuel engine. Background Art

[0002] As the world strives to reduce greenhouse gas emissions, ammonia, as a new type of carbon-free fuel, is gradually becoming a hot topic in sustainable energy research. Its unique physical and chemical properties, such as the fact that it does not produce greenhouse gas carbon dioxide as a combustion product, high hydrogen energy density, and easy storage and transportation, make ammonia have significant advantages in environmental protection and energy efficiency. Therefore, the research and development and application of ammonia-diesel dual-fuel engines are of great significance to promoting the green transformation of energy structure.

[0003] However, in actual applications, ammonia-diesel dual-fuel engines still face the problem of high emissions of unburned ammonia and nitrogen oxides, which will aggravate environmental pollution and limit the widespread promotion and application of ammonia-diesel dual-fuel engines. Summary of the invention

[0004] The purpose of the present application is to provide an exhaust gas treatment device for an ammonia-diesel dual-fuel engine, which can reduce the emission of unburned ammonia and nitrogen oxides.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] The present application provides an exhaust gas treatment device for an ammonia-diesel dual-fuel engine, the exhaust gas treatment device for an ammonia-diesel dual-fuel engine comprising: an exhaust manifold, a selective catalytic reduction device, a water spray tower, an ammonia water storage tank, an ammonia water sensor, an ammonia water injection pump, an ammonia water nozzle and a controller; the exhaust manifold is an exhaust manifold of an ammonia-diesel dual-fuel engine; the exhaust manifold, the selective catalytic reduction device and the water spray tower are connected in sequence, the ammonia water storage tank is located at the bottom of the water spray tower, the ammonia water injection pump is arranged between the ammonia water storage tank and the selective catalytic reduction device, and the ammonia water nozzle is arranged at the end of the ammonia water injection pump output pipeline;

[0007] The exhaust manifold is used to introduce the exhaust gas generated by the ammonia-diesel dual-fuel engine into the selective catalytic reduction device and the water spray tower in sequence, and the remaining gas after passing through the water spray tower is discharged into the atmosphere;

[0008] The water spray tower is used to spray ammonia solution from top to bottom, and the ammonia solution is used to absorb NH3 in the tail gas;

[0009] The ammonia water sensor is used to detect the mass concentration of ammonia in the ammonia solution in the ammonia water storage tank;

[0010] The ammonia sensor and the ammonia-diesel dual-fuel engine are both connected to the controller;

[0011] The controller is used to control the combustion efficiency of the ammonia-diesel dual-fuel engine to reach a set efficiency value when the mass concentration of ammonia in the ammonia solution reaches a first set concentration value, and at the same time, the ammonia solution in the ammonia storage tank is increased to a set pressure value through the ammonia injection pump, and is injected into the selective catalytic reduction device in a set amount through the ammonia nozzle to react with the exhaust pollutants NO in the exhaust gas. x to react;

[0012] The controller is also used to control the NH3 content in the exhaust gas emitted by the ammonia-diesel dual-fuel engine to reach a set content value when the mass concentration of ammonia in the ammonia aqueous solution is less than a first set concentration value, by spraying the ammonia aqueous solution from top to bottom in the water spray tower to adsorb ammonia in the exhaust gas, thereby increasing the mass concentration of ammonia in the ammonia aqueous solution in the ammonia storage tank until the first set concentration value is reached.

[0013] Optionally, the exhaust gas treatment device of the ammonia-diesel dual-fuel engine further comprises a three-way pipe joint, a water tank and a water pump, wherein the first pipe joint of the three-way pipe joint is connected to the ammonia storage tank through a pipeline, the second pipe joint of the three-way pipe joint is connected to the water tank through a pipeline, and the third pipe joint of the three-way pipe joint is connected to the water pump through a pipeline; the water pump is connected to the controller;

[0014] The ammonia water sensor is also used to detect the liquid level of ammonia in the ammonia water solution in the ammonia water storage tank at the bottom of the water spray tower;

[0015] The controller is also used to replenish the ammonia solution storage tank by controlling the water pump when the liquid level of the ammonia solution is lower than the set liquid level.

[0016] Optionally, the exhaust gas treatment device of the ammonia-diesel dual-fuel engine further includes a first solenoid valve and a second solenoid valve, wherein the first solenoid valve is arranged on a pipe connecting the first pipe joint and the ammonia water storage tank, and the second solenoid valve is arranged on a pipe connecting the second pipe joint and the water storage tank; the first solenoid valve and the second solenoid valve are both connected to the controller;

[0017] When the liquid level of the ammonia solution is lower than the first set concentration value, the controller controls the first solenoid valve to close, controls the second solenoid valve to open, and controls the water pump to transport water from the water storage tank to the water spray tower for spraying from top to bottom;

[0018] When the liquid level of the ammonia solution is higher than the first set concentration value, the controller controls the second solenoid valve to close and the first solenoid valve to open, and controls the water pump to transport the ammonia solution from the ammonia storage tank to the water spray tower for spraying from top to bottom. When the concentration of the ammonia solution reaches the first set concentration value, the water pump stops working, the first solenoid valve and the second solenoid valve are both closed, and the controller controls the ammonia injection pump to transport the ammonia solution to the ammonia nozzle.

[0019] Optionally, the ammonia-diesel dual-fuel engine exhaust gas treatment device further includes a heat exchanger, which is disposed between the selective catalytic reduction device and the water spray tower, and is used to cool the gas exhausted by the selective catalytic reduction device.

[0020] Optionally, the exhaust gas treatment device of the ammonia-diesel dual-fuel engine further includes a nitrogen oxide sensor, which is arranged on a pipeline between the selective catalytic reduction device and the heat exchanger; the nitrogen oxide sensor is connected to the controller;

[0021] The nitrogen oxide sensor is used to collect the gas flow of the tail gas after the selective catalytic reduction device is treated, as well as the concentration of NH3 and NO in the tail gas after the treatment. x concentration;

[0022] The controller is also used to adjust the concentration of NH3 and NO in the tail gas after treatment. x The concentration of ammonia and diesel is used to adjust the operating condition of the ammonia-diesel dual-fuel engine.

[0023] Optionally, the controller is further configured to obtain a first deviation by subtracting the concentration of NH3 in the treated exhaust gas collected by the nitrogen oxide sensor from the target NH3 concentration. x The concentration of NO x The concentration is subtracted to obtain a second deviation; and PID control is performed on the diesel injection strategy of the ammonia-diesel dual-fuel engine according to the first deviation and the second deviation.

[0024] Optionally, the exhaust gas treatment device for the ammonia diesel engine further includes an exhaust system, which is connected to the selective catalytic reduction device and is used to detect the concentration of NH3 and NO x When the concentration of NH3 or NO x When the concentration of NH3 is greater than NO x When the concentration of NH3 is less than NO xWhen the concentration is greater than 0.04, the ammonia injection pump is controlled to deliver the ammonia solution to the ammonia nozzle, and the ammonia nozzle is controlled to inject ammonia into the selective catalytic reduction device according to a set amount.

[0025] Optionally, the selective catalytic reduction device includes a gas inlet, a gas outlet and a liquid inlet, the liquid inlet is connected to the ammonia nozzle, the gas inlet is used to introduce high-temperature exhaust gas discharged from the ammonia-diesel dual-fuel engine; the gas outlet is provided with a nitrogen oxygen sensor, and the nitrogen oxygen sensor is used to detect NO in the treated exhaust gas. x and NH3 concentration;

[0026] The controller is also used to detect the NO collected by the nitrogen oxygen sensor x and NH3 concentration, and controlling the ammonia injection pump and the ammonia nozzle to adjust the amount of ammonia solution in the selective catalytic reduction device.

[0027] Optionally, the ammonia-diesel dual-fuel engine is a marine ammonia-diesel dual-fuel engine, and the aqueous solution sprayed from top to bottom by the water spray tower is an ammonia aqueous solution lower than a second set concentration value.

[0028] Optionally, the catalytic reaction equation in the selective catalytic reduction device is:

[0029]

[0030] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0031] The present application provides an exhaust gas treatment device for an ammonia-diesel dual-fuel engine. When the mass concentration of ammonia in the ammonia solution reaches a first set concentration value, the combustion efficiency of the ammonia-diesel dual-fuel engine is controlled to reach the set efficiency value, and at the same time, the ammonia solution in the ammonia storage tank is increased to a set pressure value through the ammonia injection pump, and is injected into a selective catalytic reduction device in a set amount through an ammonia nozzle to react with exhaust pollutants NOx in the exhaust gas; when the mass concentration of ammonia in the ammonia solution is less than the first set concentration value, the NH3 content in the exhaust gas discharged by the ammonia-diesel dual-fuel engine is controlled to reach a set content value, and the ammonia solution is sprayed from top to bottom in the spray tower to adsorb ammonia in the exhaust gas, thereby increasing the mass concentration of ammonia in the ammonia solution until it reaches the first set concentration value; real-time control of the exhaust gas discharged by the ammonia-diesel dual-fuel engine is achieved, and the emission of unburned ammonia and nitrogen oxides can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 A schematic structural diagram of an exhaust gas treatment device for an ammonia-diesel dual-fuel engine provided in one embodiment of the present application.

[0034] Figure 2 A schematic diagram of the working process of an ammonia-diesel dual-fuel engine exhaust treatment device provided in one embodiment of the present application.

[0035] Figure numerals: 1-ammonia-diesel dual-fuel engine, 2-exhaust manifold, 21-intake side, 22-exhaust side, 3-selective catalytic reduction device, 4-nitrogen oxide sensor, 5-heat exchanger, 6-ammonia injection pump, 7-ammonia nozzle, 8-water spray tower, 9-ammonia storage tank, 10-ammonia sensor, 11-first solenoid valve, 12-second solenoid valve, 13-water storage tank, 14-water pump. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0037] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0038] The present application provides an exhaust gas treatment device for an ammonia-diesel dual-fuel engine, such as Figure 1 As shown, an exhaust gas treatment device for an ammonia-diesel dual-fuel engine comprises: an exhaust manifold 2, a selective catalytic reduction device 3, a nitrogen oxide sensor 4, a heat exchanger 5, a water spray tower 8, an ammonia water storage tank 9, an ammonia water sensor 10, a water pump 14, a first solenoid valve 11, a second solenoid valve 12, a water storage tank 13, an ammonia water injection pump 6, an ammonia water nozzle 7 and a controller. The exhaust manifold 2 is the exhaust manifold 2 of the ammonia-diesel dual-fuel engine 1; the exhaust manifold 2, the selective catalytic reduction device 3 and the water spray tower 8 are connected in sequence, the ammonia water storage tank 9 is located at the bottom of the water spray tower 8, the ammonia water injection pump 6 is arranged between the ammonia water storage tank 9 and the selective catalytic reduction device 3, and the ammonia water nozzle 7 is arranged at the end of the output pipe of the ammonia water injection pump 6.

[0039] The exhaust manifold 2 is connected to the gas inlet of the selective catalytic reduction device 3, and the gas outlet of the selective catalytic reduction device 3 is connected to the heat exchanger 5, and the cooled exhaust gas is introduced into the water spray tower 8 through a pipeline. An ammonia water nozzle 7 is arranged at the inlet of the selective catalytic reduction device 3, which is used to spray the ammonia solution into the selective catalytic reduction device 3 at a set pressure and flow rate, and a nitrogen oxide sensor 4 is arranged at the outlet to measure the NOx and NH3 concentrations in the exhaust gas.

[0040] The engine exhaust enters from the bottom of the water spray tower 8 and is discharged to the atmosphere from the top. The water spray tower 8 is used to spray ammonia solution from top to bottom, and the ammonia solution is used to absorb NH3 in the exhaust gas. The ammonia storage tank 9 arranged at the bottom of the water spray tower 8 is used to collect the sprayed aqueous solution.

[0041] The bottom of the ammonia storage tank 9 is connected to the ammonia injection pump 6 through a pipeline. The controller can control the ammonia injection pump 6 to extract ammonia solution from the ammonia storage tank 9 and supply it to the ammonia nozzle 7 at a certain pressure and flow rate. The controller controls the ammonia nozzle 7 to inject the ammonia solution into the selective catalytic reduction device 3.

[0042] The ammonia sensor 10 and the ammonia-diesel dual-fuel engine 1 are both connected to the controller.

[0043] The controller is used to control the combustion efficiency of the ammonia-diesel dual-fuel engine 1 to reach a set efficiency value when the mass concentration of ammonia in the ammonia aqueous solution reaches a first set concentration value, and at the same time, increase the ammonia aqueous solution in the ammonia storage tank 9 to a set pressure value through the ammonia aqueous solution injection pump 6, and inject it into the selective catalytic reduction device 3 in a set amount through the ammonia aqueous solution nozzle 7 to react with the exhaust pollutants NOx in the exhaust gas.

[0044] The controller is also used to control the NH3 content in the exhaust gas emitted by the ammonia-diesel dual-fuel engine 1 to reach a set content value when the mass concentration of ammonia in the ammonia aqueous solution is less than a first set concentration value, by spraying the ammonia aqueous solution from top to bottom in the water spray tower 8 to adsorb ammonia in the exhaust gas, thereby increasing the mass concentration of ammonia in the ammonia aqueous solution in the ammonia storage tank 9 until the first set concentration value is reached.

[0045] The exhaust gas treatment device of the ammonia-diesel dual-fuel engine also includes a three-way pipe joint, a water tank 13 and a water pump 14. The first pipe joint of the three-way pipe joint is connected to the ammonia storage tank 9 through a pipeline, the second pipe joint of the three-way pipe joint is connected to the water tank 13 through a pipeline, and the third pipe joint of the three-way pipe joint is connected to the water pump 14 through a pipeline; the water pump 14 is connected to the controller.

[0046] The ammonia water sensor 10 is also used to detect the ammonia water solution level of ammonia in the ammonia water solution in the ammonia water storage tank 9 at the bottom of the water spray tower 8.

[0047] The controller is also used to replenish the ammonia solution storage tank 9 by controlling the water pump 14 when the ammonia solution level is lower than the set level.

[0048] The controller controls the opening or closing of the first solenoid valve 11 and the second solenoid valve 12 to control the water pump 14 to pump out the ammonia solution in the ammonia storage tank 9 for spraying, or controls the water pump 14 to pump out the water in the water outlet tank for spraying.

[0049] The ammonia water sensor 10 is arranged in the ammonia water storage tank 9 and is used to measure the temperature, liquid level and ammonia water concentration of the ammonia water solution in the ammonia water storage tank 9 .

[0050] The ammonia sensor 10, the ammonia injection pump 6, the ammonia nozzle 7, the nitrogen oxide sensor 4, the first solenoid valve 11, the second solenoid valve 12, the water pump 14, and the ammonia-diesel dual-fuel engine 1 are all connected to the controller.

[0051] Finally, the real-time control of the exhaust gas discharged by the ammonia-diesel dual-fuel engine 1 is achieved, which can reduce the emission of unburned ammonia and nitrogen oxides.

[0052] The heat exchanger 5 is disposed between the selective catalytic reduction device 3 and the water spray tower 8 , and the heat exchanger 5 is used to cool the gas exhausted from the selective catalytic reduction device 3 .

[0053] The nitrogen oxide sensor 4 is disposed on a pipeline between the selective catalytic reduction device 3 and the heat exchanger 5 ; the nitrogen oxide sensor 4 is connected to the controller.

[0054] The nitrogen oxide sensor 4 is used to collect the gas flow of the exhaust gas after being treated by the selective catalytic reduction device 3, as well as the concentration of NH3 and NO in the exhaust gas after being treated. x concentration.

[0055] The controller is also used to adjust the concentration of NH3 and NO in the tail gas after treatment. x The concentration of ammonia and diesel dual fuel engine 1 is adjusted to the working condition, such as Figure 2 shown.

[0056] The controller is also used to obtain a first deviation by subtracting the concentration of NH3 in the treated exhaust gas collected by the nitrogen oxide sensor 4 from the target NH3 concentration. x The concentration of NO x The concentration is subtracted to obtain a second deviation; and PID control is performed on the diesel injection strategy of the ammonia-diesel dual-fuel engine 1 according to the first deviation and the second deviation.

[0057] The exhaust gas treatment device of the ammonia diesel engine also includes an exhaust system, which is connected to the selective catalytic reduction device 3. The exhaust system is used to collect the concentration of NH3 and NO x When the concentration of NH3 or NO x When the concentration of NH3 is greater than NO x When the concentration of NH3 is less than NO x When the concentration is greater than 0.04, the ammonia solution injection pump 6 is controlled to deliver the ammonia solution to the ammonia solution nozzle 7, and the ammonia solution nozzle 7 is controlled to inject ammonia solution into the selective catalytic reduction device 3 according to the set amount.

[0058] The selective catalytic reduction device 3 includes a gas inlet, a gas outlet and a liquid inlet. The liquid inlet is connected to the ammonia nozzle 7. The gas inlet is used to introduce high-temperature exhaust gas discharged by the ammonia-diesel dual-fuel engine 1. The gas outlet is provided with a nitrogen oxygen sensor 4. The nitrogen oxygen sensor 4 is used to detect NO in the treated exhaust gas. x and NH3 concentration.

[0059] The controller is also used to detect the NO collected by the nitrogen oxygen sensor 4. x and NH 3 concentration, and controls the ammonia injection pump 6 and the ammonia nozzle 7 to adjust the amount of ammonia solution in the selective catalytic reduction device 3 .

[0060] The aqueous solution sprayed from top to bottom by the water spray tower 8 is an ammonia solution lower than the second set concentration value.

[0061] The engine mentioned in the present application is an ammonia-diesel dual-fuel engine 1. In an exemplary embodiment, the ammonia-diesel dual-fuel engine 1 is a marine ammonia-diesel dual-fuel engine 1. Ammonia can be used as a marine engine fuel. It has a high difficulty in spontaneous combustion and a slow flame propagation speed. Combining ammonia with a highly active fuel can solve some of the problems. However, as a fuel, incomplete combustion of ammonia will produce NO. x , there may also be NH3 residues, all of which may cause environmental pollution. x The residual NH3 gas content is different due to the different content of chemical components. This application can effectively solve the emission pollution in different situations.

[0062] The present application adjusts the diesel injection parameters of the ammonia-diesel dual-fuel engine 1 according to the concentration of ammonia solution and the different proportions of gas components under different working conditions to accurately adjust the ratio of ammonia and nitrogen oxides in the exhaust gas that produce greater pollution effects. The ammonia-diesel dual-fuel engine 1 is used as a marine power source, and the main exhaust pollutants are NH3 and NO x , it is necessary to match the post-treatment device to treat the exhaust pollutants. Under different speed, load, ammonia-diesel energy ratio and other working conditions, NH3 and NO x The present invention uses water as a medium, and when the exhaust emission of NH3 is high, NH3 is adsorbed by spraying to form an ammonia solution and collect it. The concentration of the ammonia solution is measured by the ammonia sensor 10. When the set concentration is reached, the controller adjusts the diesel injection parameters of the ammonia-diesel dual-fuel engine 1 to control the combustion parameters, thereby improving the combustion thermal efficiency of the ammonia-diesel dual-fuel engine 1, and thus improving the exhaust pollutant NO x The ammonia solution is injected into the selective catalytic reduction device 3 to treat NO with the ammonia solution. x . When the ammonia solution is consumed, the combustion parameters are controlled by adjusting the diesel injection parameters of the ammonia-diesel dual-fuel engine 1 to increase the NH3 content of exhaust pollutants. NH3 is adsorbed by water spraying to increase the ammonia concentration of the ammonia solution, and the cycle repeats. (The ammonia-diesel dual-fuel engine 1 uses diesel to ignite ammonia. The combustion thermal efficiency is adjusted by adjusting the diesel injection timing. When the injection timing is advanced, the combustion thermal efficiency increases and the exhaust pollutant NH3 decreases. When the injection timing is delayed, the combustion thermal efficiency decreases and the exhaust pollutant NH3 increases).

[0063] The working process of the exhaust gas treatment device of the ammonia-diesel dual-fuel engine of the present application is as follows.

[0064] 1. Determine whether to start valve water spraying according to the concentration of ammonia solution in ammonia storage tank 9.

[0065] 2. When the concentration of the ammonia solution reaches the set value, the water spray system is stopped, and the controller controls the ammonia solution injection pump 6 to transport the ammonia solution to the ammonia solution nozzle 7. The controller controls the ammonia solution nozzle 7 to inject the ammonia solution into the selective catalytic reduction device 3 at a set flow rate.

[0066] 2.1 The controller controls the ammonia-diesel dual-fuel engine 1, adjusts the fuel injection parameters, controls the inlet of the engine exhaust selective catalytic reduction device 3, NO x The concentration is higher than that of NH3.

[0067] 2.2 Exhaust NOx measured by NOx sensor 4 at outlet of selective catalytic reduction device 3 x and NH3 concentration.

[0068] 2.3NO xWhen the concentration is higher than the target value, the flow rate of the ammonia solution sprayed by the ammonia solution nozzle 7 is increased.

[0069] 2.4NO x When the concentration is lower than the target value, the flow rate of the ammonia solution sprayed by the ammonia solution nozzle 7 is reduced.

[0070] 3. When the concentration of ammonia solution is lower than the set value, turn on the water spray system.

[0071] 3.1 The controller controls the ammonia-diesel dual-fuel engine 1, adjusts the fuel injection parameters, controls the inlet of the engine exhaust selective catalytic reduction device 3, NO x The concentration is lower than that of NH3.

[0072] 3.2 When the liquid level of the ammonia solution in the ammonia storage tank 9 is lower than the set value, the first solenoid valve 11 is closed, the second solenoid valve 12 is opened, and the water pump 14 draws water from the water storage tank 13 for spraying until the set liquid level is reached.

[0073] 3.3 When the liquid level of the ammonia solution in the ammonia solution storage tank 9 is higher than the set value, the first solenoid valve 11 is opened, the second solenoid valve 12 is closed, and the water pump 14 draws the aqueous solution from the ammonia solution storage tank 9 for spraying until the set concentration is reached. Enter 1 reciprocating cycle.

[0074] The exhaust gas treatment device of the ammonia-diesel dual-fuel engine of the present application comprises a selective catalytic reduction system, an exhaust gas cooling system, a spray system and a control system. The control system comprises a controller.

[0075] The selective catalytic reduction system mainly includes a selective catalytic reduction device 3, an ammonia injection pump 6, an ammonia nozzle 7, a nitrogen oxide sensor 4 and other equipment. The exhaust gas generated by the ammonia diesel dual-fuel engine 1 is introduced into the gas inlet of the selective catalytic reduction device 3 through the exhaust manifold 2, and the nitrogen oxide sensor 4 is arranged at the gas outlet of the selective catalytic reduction device 3. The controller detects NH3 and NO in the exhaust gas according to the nitrogen oxide sensor 4. x concentration, and the demand for NH3 and NO x When NO x When the measured concentration is higher than the required concentration, increase the injection amount of the ammonia injection pump 6 and the ammonia nozzle 7. x When the measured concentration is lower than the required concentration, the injection amount of the ammonia injection pump 6 and the ammonia nozzle 7 is reduced to achieve closed-loop control.

[0076] The selective catalytic reduction device 3 includes a gas inlet and a liquid inlet. The liquid inlet is used to introduce ammonia solution in the ammonia storage tank 9 at the bottom of the water spray tower 8, and the gas inlet is used to introduce engine exhaust gas; the gas outlet is provided with a nitrogen oxygen sensor 4, and the nitrogen oxygen sensor 4 is used to detect NH3 and NO in the exhaust gas. x concentration.

[0077] The basic principle of the selective catalytic reduction device 3 is to use NH3 to reduce NO x The reduction function is achieved by using ammonia as a reducing agent, and a certain concentration of ammonia solution is sprayed into the selective catalytic reduction device 3 through an ammonia injection pump and an ammonia nozzle to react with NO in the exhaust gas. x After mixing, it diffuses to the catalyst surface, and under the action of the catalyst, ammonia (NH3) reduces NO and NO2 in the exhaust gas into harmless nitrogen (N2) and water (H2O).

[0078] The catalytic reaction equation in the selective catalytic reduction device 3 is:

[0079] The exhaust gas treatment device of the ammonia-diesel dual-fuel engine also includes an exhaust gas cooling system, which mainly includes a heat exchanger 5, which cools the exhaust gas to less than 100° C. through heat exchange between cooling water and high-temperature exhaust gas.

[0080] The spray system mainly includes a water spray tower 8, an ammonia storage tank 9, an ammonia sensor 10, a first solenoid valve 11, a second solenoid valve 12, a water tank 13, a water pump 14, a nozzle and connecting pipes, etc. The ammonia storage tank 9 is arranged at the lower part of the water spray tower 8 to collect the aqueous solution under spraying. The ammonia sensor 10 is arranged at the bottom of the ammonia storage tank 9. The ammonia storage tank 9 and the water tank 13 are connected to the inlet of the water pump 14 through a tee, and the pipeline switch is controlled by a solenoid valve. The outlet of the water pump 14 is connected to the nozzle in the water spray tower 8 through a pipeline.

[0081] The ammonia sensor 10 arranged in the ammonia storage tank 9 identifies the temperature, liquid level and ammonia concentration of the ammonia solution, calculates the amount of ammonia solution in the ammonia storage tank 9 and the amount of NH3 required to meet the set concentration requirement, and then calculates the theoretical ammonia flow rate in the tail gas to be processed under this working condition, and then feedback controls the ammonia-diesel dual-fuel engine 1, adjusts the diesel injection parameters, and regulates the NH3 and NO x ratio, so that the NH3 concentration in the exhaust gas discharged by the engine is higher than that of NO x After the ammonia solution reaches the set concentration, the water pump 14 stops working, the spray tower stops spraying, and the ammonia-diesel dual-fuel engine 1 is feedback-controlled to adjust the diesel injection parameters and regulate the NH3 and NO x ratio, so that the NO x The concentration is higher than that of NH3. The above control achieves high combustion thermal efficiency, NH3 recycling and low harmful gas pollutant emissions. Water is used as the medium to cyclically adsorb and release NH3, making full use of the NH3 discharged from the tail gas to treat the NO discharged from the tail gas. x , improve energy utilization.

[0082] When the liquid level of the ammonia solution in the ammonia storage tank 9 is higher than the set value, the controller controls the first solenoid valve 11 to open and the second solenoid valve 12 to close, and the aqueous solution sprayed from top to bottom by the water spray tower 8 is an ammonia solution with a concentration lower than the set concentration. When the liquid level of the ammonia solution in the ammonia storage tank 9 is lower than the set value, the controller controls the second solenoid valve 12 to open and the first solenoid valve 11 to close, and the aqueous solution sprayed from top to bottom by the water spray tower 8 is the water in the water storage tank 13, and the ammonia storage tank 9 is replenished with water until the set liquid level is reached, thereby realizing automatic water replenishment of the system.

[0083] The present application makes full use of exhaust pollutants from the ammonia-diesel dual-fuel engine 1 through mechanical systems, sensors and electronic control systems, improves the utilization of exhaust pollutants and the efficiency of exhaust treatment, controls the operating conditions of the ammonia-diesel dual-fuel engine 1, improves the combustion thermal efficiency of the ammonia-diesel dual-fuel engine 1, and reduces air pollution caused by exhaust emissions.

[0084] The controller is also used to determine the content of NH3 and NO in the tail gas. x The concentration of ammonia is controlled to control the ammonia injection pump 6 and the ammonia nozzle 7.

[0085] The electronic control system of this application is based on the NH3 and NO in the exhaust gas measured by the nitrogen oxygen sensor 4. x concentration, and the set NH3 and NO x The concentration is compared to calculate the theoretical required ammonia solution flow rate that takes into account both ammonia dissolution and reduction of nitrogen oxide pollutants. The ammonia solution is injected into the selective reduction device through the ammonia injection pump 6 and the ammonia nozzle 7 to supplement the NH3 and NO in the tail gas. x Carry out chemical reaction to reduce NH3 and NO in tail gas x concentration, forming a closed-loop control.

[0086] The present invention controls the combustion parameters of the ammonia-diesel dual-fuel engine 1, thereby controlling the exhaust pollutants NH3 and NO X The ratio of NH3 to NH4 is used to balance the thermal efficiency of the engine and the concentration of exhaust pollutants by adjusting the ammonia-diesel dual-fuel engine 1 under different speed, load, ammonia-diesel energy ratio and other working conditions. Water is used as a medium for storing ammonia. Water can absorb a large amount of NH3 to form an ammonia solution. When the set ratio is reached, the ammonia solution is used to treat the NO in the exhaust gas. x . Realize the reuse of tail gas ammonia and save energy.

[0087] This application adjusts the proportion of ammonia and nitrogen oxides discharged under different fuel combustion modes, measures the concentration of ammonia solution generated by tail gas treatment, and achieves simultaneous reduction of nitrogen oxides and residual ammonia concentrations in the tail gas treatment system through coordinated control of various components of the tail gas treatment system, improves tail gas treatment efficiency, and optimizes the control system of ammonia treatment, and ultimately achieves closed-loop control of nitrogen oxides and ammonia concentrations in tail gas emissions. This helps reduce pollutant emissions, especially unburned ammonia and nitrogen oxides, and makes positive contributions to promoting the widespread application of clean energy and addressing global climate change.

[0088] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0089] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. An exhaust gas treatment device for an ammonia-diesel dual-fuel engine, characterized in that: The exhaust gas treatment device of the ammonia-diesel dual-fuel engine comprises: an exhaust manifold, a selective catalytic reduction device, a water spray tower, an ammonia water storage tank, an ammonia water sensor, an ammonia water injection pump, an ammonia water nozzle and a controller; the exhaust manifold is the exhaust manifold of the ammonia-diesel dual-fuel engine; the exhaust manifold, the selective catalytic reduction device and the water spray tower are connected in sequence, the ammonia water storage tank is located at the bottom of the water spray tower, the ammonia water injection pump is arranged between the ammonia water storage tank and the selective catalytic reduction device, and the ammonia water nozzle is arranged at the end of the ammonia water injection pump output pipeline; The exhaust manifold is used to guide the exhaust gas generated by the ammonia-diesel dual-fuel engine into the selective catalytic reduction device and the water spray tower in sequence, and the remaining gas after passing through the water spray tower is discharged into the atmosphere; The water spray tower is used to spray ammonia solution from top to bottom, and the ammonia solution is used to absorb NH3 in the tail gas; The ammonia water sensor is used to detect the mass concentration of ammonia in the ammonia solution in the ammonia water storage tank; The ammonia sensor and the ammonia-diesel dual-fuel engine are both connected to the controller; The controller is used to control the combustion efficiency of the ammonia-diesel dual-fuel engine to reach a set efficiency value when the mass concentration of ammonia in the ammonia solution reaches a first set concentration value, and at the same time, the ammonia solution in the ammonia storage tank is increased to a set pressure value through the ammonia injection pump, and is injected into the selective catalytic reduction device in a set amount through the ammonia nozzle to react with the exhaust pollutants NO in the exhaust gas. x to react; The controller is also used to control the NH3 content in the exhaust gas emitted by the ammonia-diesel dual-fuel engine to reach a set content value when the mass concentration of ammonia in the ammonia aqueous solution is less than a first set concentration value, by spraying the ammonia aqueous solution from top to bottom in the water spray tower to adsorb ammonia in the exhaust gas, thereby increasing the mass concentration of ammonia in the ammonia aqueous solution in the ammonia storage tank until the first set concentration value is reached.

2. The exhaust gas treatment device of an ammonia-diesel dual-fuel engine according to claim 1, characterized in that: The exhaust gas treatment device of the ammonia-diesel dual-fuel engine also includes a three-way pipe joint, a water tank and a water pump, wherein the first pipe joint of the three-way pipe joint is connected to the ammonia water storage tank through a pipeline, the second pipe joint of the three-way pipe joint is connected to the water tank through a pipeline, and the third pipe joint of the three-way pipe joint is connected to the water pump through a pipeline; the water pump is connected to the controller; The ammonia water sensor is also used to detect the liquid level of ammonia in the ammonia water solution in the ammonia water storage tank at the bottom of the water spray tower; The controller is also used to replenish the ammonia solution storage tank by controlling the water pump when the liquid level of the ammonia solution is lower than the set liquid level.

3. The exhaust gas treatment device of an ammonia-diesel dual-fuel engine according to claim 2 is characterized in that: The exhaust gas treatment device of the ammonia-diesel dual-fuel engine also includes a first solenoid valve and a second solenoid valve, wherein the first solenoid valve is arranged on a pipe connecting the first pipe joint and the ammonia water storage tank, and the second solenoid valve is arranged on a pipe connecting the second pipe joint and the water storage tank; the first solenoid valve and the second solenoid valve are both connected to the controller; When the liquid level of the ammonia solution is lower than the first set concentration value, the controller controls the first solenoid valve to close, controls the second solenoid valve to open, and controls the water pump to transport water from the water storage tank to the water spray tower for spraying from top to bottom; When the liquid level of the ammonia solution is higher than the first set concentration value, the controller controls the second solenoid valve to close and the first solenoid valve to open, and controls the water pump to transport the ammonia solution from the ammonia storage tank to the water spray tower for spraying from top to bottom. When the concentration of the ammonia solution reaches the first set concentration value, the water pump stops working, the first solenoid valve and the second solenoid valve are both closed, and the controller controls the ammonia injection pump to transport the ammonia solution to the ammonia nozzle.

4. The exhaust gas treatment device of an ammonia-diesel dual-fuel engine according to claim 1, characterized in that: The exhaust gas treatment device of the ammonia-diesel dual-fuel engine also includes a heat exchanger, which is arranged between the selective catalytic reduction device and the water spray tower, and is used to cool the gas discharged from the selective catalytic reduction device.

5. The exhaust gas treatment device of an ammonia-diesel dual-fuel engine according to claim 4 is characterized in that: The exhaust gas treatment device of the ammonia-diesel dual-fuel engine further includes a nitrogen oxide sensor, which is arranged on a pipeline between the selective catalytic reduction device and the heat exchanger; the nitrogen oxide sensor is connected to the controller; The nitrogen oxide sensor is used to collect the gas flow of the tail gas after the selective catalytic reduction device is treated, as well as the concentration of NH3 and NO in the tail gas after the treatment. x concentration; The controller is also used to adjust the concentration of NH3 and NO in the tail gas after treatment. x The concentration of ammonia and diesel is used to adjust the operating condition of the ammonia-diesel dual-fuel engine.

6. The exhaust gas treatment device of an ammonia-diesel dual-fuel engine according to claim 5, characterized in that: The controller is also used to obtain a first deviation by subtracting the concentration of NH3 in the treated exhaust gas collected by the nitrogen oxide sensor from the target NH3 concentration. x The concentration of NO x The concentration is subtracted to obtain a second deviation; and PID control is performed on the diesel injection strategy of the ammonia-diesel dual-fuel engine according to the first deviation and the second deviation.

7. The exhaust gas treatment device of an ammonia-diesel dual-fuel engine according to claim 5, characterized in that: The exhaust gas treatment device of the ammonia diesel engine also includes an exhaust system, which is connected to the selective catalytic reduction device. The exhaust system is used to collect the concentration of NH3 and NO x When the concentration of NH3 or NO x When the concentration of NH3 is greater than NO x When the concentration of NH3 is less than NO x When the concentration is greater than 0.04, the ammonia injection pump is controlled to deliver the ammonia solution to the ammonia nozzle, and the ammonia nozzle is controlled to inject ammonia into the selective catalytic reduction device according to a set amount.

8. The exhaust gas treatment device of an ammonia-diesel dual-fuel engine according to claim 1, characterized in that: The selective catalytic reduction device comprises a gas inlet, a gas outlet and a liquid inlet, wherein the liquid inlet is connected to the ammonia nozzle, the gas inlet is used to introduce high-temperature exhaust gas discharged by the ammonia-diesel dual-fuel engine; the gas outlet is provided with a nitrogen oxygen sensor, and the nitrogen oxygen sensor is used to detect NO in the treated exhaust gas. x and NH3 concentration; The controller is also used to detect the NO collected by the nitrogen oxygen sensor x and NH3 concentration, and controlling the ammonia injection pump and the ammonia nozzle to adjust the amount of ammonia solution in the selective catalytic reduction device.

9. The exhaust gas treatment device of an ammonia-diesel dual-fuel engine according to claim 1, characterized in that: The ammonia-diesel dual-fuel engine is a marine ammonia-diesel dual-fuel engine, and the aqueous solution sprayed from top to bottom by the water spray tower is an ammonia aqueous solution lower than the second set concentration value.

10. The exhaust gas treatment device of an ammonia-diesel dual-fuel engine according to claim 1, characterized in that: The catalytic reaction equation in the selective catalytic reduction device is:

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