Liquid ammonia injection system

Abstract

The utility model relates to the technical field of tail gas treatment, in particular to a liquid ammonia injection system, a heating layer and a heat preservation layer are arranged on an ammonia gas pipe, when the environment temperature is low, the ammonia gas pipe is heated by the heating layer, so that the temperature of ammonia gas in the ammonia gas pipe is guaranteed, low-temperature liquefaction of the ammonia gas is avoided, and the ammonia gas pipe is subjected to heat preservation by the heat preservation layer; the temperature of the ammonia gas in the ammonia gas pipe is further guaranteed, the ammonia gas can be prevented from being influenced by the environment temperature in the discharging process, and the tail gas treatment efficiency is guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of tail gas treatment, and in particular to a liquid ammonia injection system. Background Art

[0002] Under the premise of increasingly stringent automobile exhaust emission standards, exhaust gas treatment requires an efficient and energy-saving method. Due to the high efficiency and energy-saving characteristics of ammonia in exhaust gas catalytic reduction purification, some existing technologies use liquid ammonia injection devices for exhaust gas treatment. However, there are still some problems in the existing liquid ammonia injection devices. For example, when the ambient temperature is low, the ammonia will be affected by the ambient temperature during the process of being discharged into the exhaust pipe, resulting in low-temperature liquefaction of the ammonia, which reduces the efficiency of exhaust gas treatment. Therefore, it is necessary to study a liquid ammonia injection system that can prevent the ammonia from being affected by the ambient temperature during the emission process.

[0003] There is currently no effective technical solution to the above problems. Utility Model Content

[0004] The purpose of the present application is to provide a liquid ammonia injection system, which can prevent ammonia from being affected by ambient temperature during the emission process and ensure the efficiency of exhaust gas treatment.

[0005] The present application provides a liquid ammonia injection system, including a liquid ammonia tank, a pressure temperature liquid level sensor, a heating device, an ammonia pipe, a nozzle and a controller;

[0006] The liquid ammonia tank is provided with the pressure-temperature-level sensor, and the pressure-temperature-level sensor is used to detect the pressure, temperature and level of the liquid ammonia in the liquid ammonia tank. The heating device is arranged in the liquid ammonia tank, and the heating device is used to heat the liquid ammonia in the liquid ammonia tank to generate ammonia gas. The inlet of the ammonia pipe is connected to the outlet of the liquid ammonia tank, and the outlet of the ammonia pipe is connected to the nozzle. The ammonia pipe is provided with a heating layer and a thermal insulation layer, and the heating layer is arranged between the ammonia pipe and the thermal insulation layer. The heating layer is used to heat the ammonia pipe, and the thermal insulation layer is used to insulate the ammonia pipe. The controller is respectively connected to the pressure-temperature-level sensor, the heating device and the nozzle, and the controller is used to control the heating device according to the detection data of the pressure-temperature-level sensor, and the controller is used to control the nozzle according to the detection data of the external nitrogen and oxygen sensor.

[0007] Through the above arrangement, the ammonia gas can be prevented from being affected by the ambient temperature during the emission process, thereby ensuring the efficiency of the exhaust gas treatment.

[0008] Optionally, the heating layer is a self-limiting temperature heating material.

[0009] Through the above arrangement, precise temperature control can be achieved.

[0010] Optionally, the self-limiting temperature heating material includes a self-limiting temperature electric heating tape or a self-limiting temperature heating sheet.

[0011] Optionally, the thermal insulation layer is made of polyurethane foam material.

[0012] Through the above arrangement, a good thermal insulation effect is provided for the ammonia pipe.

[0013] Optionally, the material of the ammonia pipe is any one of EPDM rubber, polylaurolactam, polytetrafluoroethylene or silicone.

[0014] Optionally, the heating device is an electric heating wire.

[0015] Optionally, the heating device is a hot water heating pipe.

[0016] Optionally, a manual stop valve is provided on a side of the ammonia pipe close to the liquid ammonia tank.

[0017] Optionally, a mechanical pressure reducing valve is provided on a side of the ammonia pipe close to the nozzle, the mechanical pressure reducing valve is connected to the controller, and the mechanical pressure reducing valve is used to adjust the injection pressure of the nozzle.

[0018] Optionally, the ammonia pipe is provided with a first solenoid valve, which is arranged between the manual stop valve and the mechanical pressure reducing valve, and is connected to the controller. The first solenoid valve is used to switch the flow direction in the ammonia pipe when liquid ammonia is added to the liquid ammonia tank.

[0019] Beneficial effect: The liquid ammonia injection system provided by the present application sets a heating layer and a thermal insulation layer on the ammonia pipe. When the ambient temperature is low, the heating layer heats the ammonia pipe, thereby ensuring the temperature of the ammonia in the ammonia pipe and avoiding low-temperature liquefaction of the ammonia. The thermal insulation layer insulates the ammonia pipe to further ensure the temperature of the ammonia in the ammonia pipe, which can avoid the ammonia being affected by the ambient temperature during the emission process and ensure the efficiency of the exhaust gas treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the overall structure of the liquid ammonia injection system provided in this application.

[0021] Figure 2 Schematic diagram of the position of the electric heating wire and the liquid ammonia tank provided in this application.

[0022] Figure 3 Schematic diagram of the location of the hot water heating pipe and liquid ammonia tank provided for this application.

[0023] Explanation of reference numerals: 10, liquid ammonia tank; 20, pressure, temperature and liquid level sensor; 30, heating device; 301, electric heating wire; 302, hot water heating pipe; 3021, hot water inlet; 3022, hot water reflux outlet; 3023, second solenoid valve; 40, ammonia pipe; 50, nozzle; 60, controller; 70, manual stop valve; 80, mechanical pressure reducing valve; 90, first solenoid valve; 110, external nitrogen oxide sensor. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0025] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0026] The present application provides a liquid ammonia injection system, including a liquid ammonia tank 10, a pressure temperature liquid level sensor 20, a heating device 30, an ammonia pipe 40, a nozzle 50 and a controller 60;

[0027] The liquid ammonia tank 10 is provided with a pressure-temperature-liquid level sensor 20. The pressure-temperature-liquid level sensor 20 (i.e., a device integrating pressure detection function, temperature detection function, and liquid level detection function) is used to detect the pressure, temperature, and liquid level of the liquid ammonia in the liquid ammonia tank 10. The heating device 30 is provided in the liquid ammonia tank 10. The heating device 30 is used to heat the liquid ammonia in the liquid ammonia tank 10 to generate ammonia gas. The inlet of the ammonia pipe 40 is connected to the outlet of the liquid ammonia tank 10. The outlet of the ammonia pipe 40 is connected to the nozzle 50. The ammonia pipe 40 is provided with a heating layer and a thermal insulation layer. The heating layer is provided between the ammonia pipe 40 and the thermal insulation layer. The heating layer is used to heat the ammonia pipe 40. The thermal insulation layer is used to keep the ammonia pipe 40 warm. The controller 60 is respectively connected to the pressure-temperature-liquid level sensor 20, the heating device 30, and the nozzle 50. The controller 60 is used to control the heating device 30 according to the detection data of the pressure-temperature-liquid level sensor 20. The controller 60 is used to control the nozzle 50 according to the detection data of the external nitrogen and oxygen sensor 110.

[0028] Specifically, Figure 1 As shown, by arranging a heating layer and a heat preservation layer on the ammonia pipe 40, when the ambient temperature is low, the ammonia pipe 40 is heated by the heating layer, thereby ensuring the temperature of the ammonia in the ammonia pipe 40, avoiding the low-temperature liquefaction of the ammonia, and the heat preservation layer is used to insulate the ammonia pipe 40, further ensuring the temperature of the ammonia in the ammonia pipe 40, which can avoid the ammonia being affected by the ambient temperature during the discharge process, and ensure the efficiency of the tail gas treatment. In actual application, the controller 60 controls the operation of the heating device 30 according to the detection data of the pressure temperature liquid level sensor 20, heats the liquid ammonia in the liquid ammonia tank 10 to generate ammonia, and the ammonia is discharged from the outlet of the liquid ammonia tank 10 to the ammonia pipe 40, and the controller 60 adjusts the injection amount of the nozzle 50 according to the detection data (nitrogen and oxygen content) of the external nitrogen and oxygen sensor 110.

[0029] In some embodiments, the heating layer is a self-limiting temperature heating material.

[0030] Specifically, self-limiting temperature heating materials are existing technologies, usually referring to electric heating products with self-control temperature functions. Such products can automatically adjust power output according to changes in ambient temperature, thereby achieving precise temperature control, such as self-limiting temperature heating tapes and self-limiting temperature heating sheets. Among them, self-limiting temperature heating tapes are usually composed of conductive PTC materials and two parallel metal busbars. When current passes through these materials, heat is generated. As the temperature rises, the resistance of the PTC material increases, resulting in a decrease in current, thereby achieving self-regulation of temperature. Self-limiting temperature heating sheets are a type of heating element in the form of a thin film, usually composed of a polymer matrix and a conductive filler (such as carbon black or metal powder), with good conductivity and thermal stability.

[0031] In some embodiments, the self-limiting temperature heating material includes a self-limiting temperature electric heating tape or a self-limiting temperature heating sheet.

[0032] Specifically, the self-limiting temperature electric heating tape or the self-limiting temperature electric heating sheet can be conveniently arranged on the outer wall of the ammonia pipe 40 to heat the ammonia pipe 40 .

[0033] In some embodiments, the insulation layer is a polyurethane foam material.

[0034] Specifically, the polyurethane foam material has low density, high strength, good thermal insulation performance and sound absorption performance, and provides good thermal insulation effect for the ammonia pipe 40 .

[0035] In some embodiments, the material of the ammonia pipe 40 is any one of EPDM rubber, polylaurolactam, polytetrafluoroethylene or silicone.

[0036] Specifically, EPDM has the characteristics of aging resistance, heat resistance, electrical insulation and chemical resistance. The melting temperature of polylaurolactam (commonly known as nylon 12) is 240°C-300°C. Polylaurolactam also has the characteristics of low water absorption, low temperature resistance, oil resistance and wear resistance. The operating temperature range of polytetrafluoroethylene is very wide, and it can maintain stable performance from -200°C to +250°C. Polytetrafluoroethylene also has a very low friction coefficient and excellent chemical corrosion resistance, and can resist strong acids, strong alkalis and strong oxidants; silicone can withstand temperatures as high as 300°C, and can also work normally in an environment of -100°C. Silicone also has excellent electrical insulation and chemical inertness, and is very stable to thermal oxidation and ozone. Therefore, in order to extend the service life of the ammonia pipe 40, the material of the ammonia pipe 40 can be any one of EPDM, polylaurolactam, polytetrafluoroethylene or silicone.

[0037] In some embodiments, the heating device 30 is an electric heating wire 301 .

[0038] Specifically, Figure 2 As shown, by setting the heating device 30 as an electric heating wire 301, the liquid ammonia in the liquid ammonia tank 10 can be heated conveniently and directly, wherein the material of the electric heating wire 301 can be nickel-chromium alloy, iron-chromium-aluminum or tungsten wire, etc., which have good chemical stability and antioxidant properties at high temperatures and will not directly react with the liquid ammonia or ammonia gas in the liquid ammonia tank 10, wherein the electric heating wire 301 is electrically connected to an external power supply.

[0039] In some embodiments, the heating device 30 is a hot water heating pipe 302 .

[0040] Specifically, Figure 3 The hot water heating pipe 302 shown can also heat the liquid ammonia in the liquid ammonia tank 10. In actual application, the hot water heating pipe 302 has a hot water inlet 3021 and a hot water reflux outlet 3022. Hot water enters the hot water heating pipe 302 from the hot water inlet 3021, heats the liquid ammonia in the liquid ammonia tank 10 by heat transfer, and then flows out from the hot water reflux outlet 3022. A second solenoid valve 3023 is provided at the hot water inlet 3021 end of the hot water heating pipe 302. The second solenoid valve 3023 is connected to the controller 60. The controller 60 controls the switch of the second solenoid valve 3023 according to the detection data of the pressure, temperature and liquid level sensor 20. The hot water inlet 3021 is connected to the outlet of the external hot water tank, and the hot water reflux outlet 3022 is connected to the inlet of the external hot water tank.

[0041] In some embodiments, a manual stop valve 70 is provided on a side of the ammonia pipe 40 close to the liquid ammonia tank 10 .

[0042] Specifically, in order to meet the safety requirements of the liquid ammonia tank 10, a manual stop valve 70 is provided on the side of the ammonia pipe 40 close to the liquid ammonia tank 10. For example, when the ammonia pipe 40 leaks and needs to be repaired or the nozzle 50 needs to be replaced, the manual stop valve 70 is closed to prevent the ammonia in the liquid ammonia tank 10 from being discharged into the ammonia pipe 40.

[0043] In some embodiments, a mechanical pressure reducing valve 80 is disposed on one side of the ammonia pipe 40 close to the nozzle 50 . The mechanical pressure reducing valve 80 is connected to the controller 60 . The mechanical pressure reducing valve 80 is used to adjust the injection pressure of the nozzle 50 .

[0044] Specifically, according to the command of the controller 60, the mechanical pressure reducing valve 80 can be adjusted to adjust the pressure of the ammonia gas discharged from the liquid ammonia tank 10, so that the ammonia gas sprayed from the nozzle 50 meets the pressure range required for quantitative injection, wherein the mechanical pressure reducing valve 80 is a prior art and will not be described in detail here.

[0045] In some embodiments, the ammonia pipe 40 is provided with a first solenoid valve 90, which is arranged between the manual stop valve 70 and the mechanical pressure reducing valve 80, and is connected to the controller 60. The first solenoid valve 90 is used to switch the flow direction in the ammonia pipe 40 when liquid ammonia is added to the liquid ammonia tank 10.

[0046] Specifically, by setting the first solenoid valve 90, when the ammonia injection is working, the air flow direction in the ammonia pipe 40 is from the liquid ammonia tank 10 to the nozzle 50, and when liquid ammonia needs to be added to the liquid ammonia tank 10, the first solenoid valve 90 is controlled to change the flow direction in the ammonia pipe 40, so that the liquid ammonia flows from the nozzle 50 to the liquid ammonia tank 10, thereby eliminating the need to set up additional equipment for adding liquid ammonia, which is beneficial to reducing production costs.

[0047] In this document, relational terms such as first and second, etc. are used merely to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0048] The above are only embodiments of the present application and are not intended to limit the scope of protection of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of protection of the present application.

Claims

1. A liquid ammonia injection system, characterized in that: It comprises a liquid ammonia tank (10), a pressure temperature liquid level sensor (20), a heating device (30), an ammonia pipe (40), a nozzle (50) and a controller (60); The liquid ammonia tank (10) is provided with the pressure-temperature-liquid-level sensor (20), and the pressure-temperature-liquid-level sensor (20) is used to detect the pressure, temperature and liquid level of the liquid ammonia in the liquid ammonia tank (10). The heating device (30) is provided in the liquid ammonia tank (10), and the heating device (30) is used to heat the liquid ammonia in the liquid ammonia tank (10) to generate ammonia gas. The inlet of the ammonia pipe (40) is connected to the outlet of the liquid ammonia tank (10), and the outlet of the ammonia pipe (40) is connected to the nozzle (50). The ammonia pipe (40) is provided with a heating layer and a heat-insulating layer. The heating layer is arranged between the ammonia pipe (40) and the insulation layer, the heating layer is used to heat the ammonia pipe (40), the insulation layer is used to keep the ammonia pipe (40) warm, the controller (60) is respectively connected to the pressure-temperature-level sensor (20), the heating device (30) and the nozzle (50), the controller (60) is used to control the heating device (30) according to detection data of the pressure-temperature-level sensor (20), and the controller (60) is used to control the nozzle (50) according to detection data of an external nitrogen and oxygen sensor.

2. The liquid ammonia injection system according to claim 1, characterized in that: The heating layer is a self-limiting temperature heating material.

3. The liquid ammonia injection system according to claim 2, characterized in that: Self-limiting temperature heating materials include self-limiting temperature electric heating tapes or self-limiting temperature heating sheets.

4. The liquid ammonia injection system according to claim 1, characterized in that: The thermal insulation layer is made of polyurethane foam material.

5. The liquid ammonia injection system according to claim 1, characterized in that: The material of the ammonia pipe (40) is any one of EPDM rubber, polylaurolactam, polytetrafluoroethylene or silica gel.

6. The liquid ammonia injection system according to claim 1, characterized in that: The heating device (30) is an electric heating wire (301).

7. The liquid ammonia injection system according to claim 1, characterized in that: The heating device (30) is a hot water heating pipe (302).

8. The liquid ammonia injection system according to claim 1, characterized in that: A manual stop valve (70) is provided on a side of the ammonia pipe (40) close to the liquid ammonia tank (10).

9. The liquid ammonia injection system according to claim 8, characterized in that: A mechanical pressure reducing valve (80) is provided on a side of the ammonia pipe (40) close to the nozzle (50), the mechanical pressure reducing valve (80) is connected to the controller (60), and the mechanical pressure reducing valve (80) is used to adjust the injection pressure of the nozzle (50).

10. The liquid ammonia injection system according to claim 9, characterized in that: The ammonia pipe (40) is provided with a first solenoid valve (90), the first solenoid valve (90) being arranged between the manual stop valve (70) and the mechanical pressure reducing valve (80), the first solenoid valve (90) being connected to the controller (60), and the first solenoid valve (90) being used to switch the flow direction in the ammonia pipe (40) when liquid ammonia is added to the liquid ammonia tank (10).

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