A crankcase exhaust gas treatment system and method for an ammonia engine

Abstract

This invention discloses an ammonia engine crankcase exhaust gas treatment system and method. The ammonia engine crankcase exhaust gas treatment system includes an ammonia engine. The ammonia engine is connected to an oil-gas separator via an external interface of the engine crankcase. The outlet of the oil-gas separator is connected to a throttle valve, and the other end of the throttle valve is connected to a blower. The blower is connected to a selective catalytic reduction (SCR) device via the engine exhaust pipe. The throttle valve, blower, and SCR device are all electrically connected to a controller. This system can introduce ammonia contained in the crankcase exhaust gas into the SCR device as a reducing agent for NOx purification. This not only treats the ammonia in the crankcase exhaust gas, preventing it from being directly released into the atmosphere and avoiding safety hazards, but also reduces the amount of ammonia used by the SCR device, saving costs.

Description

Technical Field

[0001] This invention relates to the field of ammonia engine control, and more particularly to an ammonia engine crankcase exhaust gas treatment system and method. Background Technology

[0002] Ammonia is carbon-free and can be synthesized from green hydrogen and nitrogen in the air, making it a very promising zero-carbon fuel. Using ammonia in engines can effectively reduce carbon emissions. However, ammonia engines also produce ammonia in their crankcase exhaust. Since ammonia is toxic, directly releasing the crankcase exhaust into the atmosphere like a diesel engine would pose uncontrollable safety risks. Therefore, a system and method for treating ammonia in the crankcase exhaust of ammonia engines is needed. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention discloses an ammonia engine crankcase exhaust gas treatment system, comprising: an ammonia engine, wherein the ammonia engine is connected to an oil-gas separator via an external interface of the engine crankcase, the outlet of the oil-gas separator is connected to a throttle valve, the other end of the throttle valve is connected to a blower, the blower is connected to a selective catalytic reduction device via an engine exhaust pipe, and the throttle valve, blower, and selective catalytic reduction device are electrically connected to a controller, wherein the controller controls the working state of the blower, extracts the exhaust gas flowing out of the external interface of the engine crankcase, merges it with the engine exhaust pipe, and then enters the selective catalytic reduction device.

[0004] The controller controls the opening of the throttle valve so that when the fan draws exhaust gas from the crankcase, the pressure inside the crankcase meets the engine's operating requirements.

[0005] A pressure sensor for detecting the pressure inside the crankcase is installed on the connecting pipeline between the ammonia engine and the oil-gas separator.

[0006] NOx sensors for detecting NOx concentration in exhaust gas are installed on the inlet and outlet pipelines of the selective catalytic reduction equipment.

[0007] A method for operating an ammonia engine crankcase exhaust gas treatment system includes the following steps:

[0008] The controller starts the fan to work after detecting that the ammonia engine speed has reached idle speed;

[0009] The controller opens the throttle valve and receives the crankcase pressure signal collected by the pressure sensor. The controller adjusts the opening of the throttle valve in real time according to the preset crankcase pressure value to keep the crankcase pressure at the preset value.

[0010] The controller receives NOx concentration information at the inlet and outlet of the selective catalytic reduction device from the NOx sensor. At the same time, the controller calculates the amount of ammonia required by the selective catalytic reduction device based on the engine's real-time speed, power, and the difference between the inlet and outlet NOx concentrations, and injects it into the selective catalytic reduction device to reduce the NOx in the exhaust gas.

[0011] By adopting the above technical solution, the ammonia engine crankcase exhaust gas treatment system and method provided by the present invention can introduce the ammonia contained in the crankcase exhaust gas into a selective catalytic reduction device as a reducing agent for purifying NOx. In this way, the ammonia in the crankcase exhaust gas is treated so that it is not directly discharged into the atmosphere, thus avoiding safety hazards. It also reduces the amount of ammonia used as a reducing agent in the selective catalytic reduction device, thus saving costs. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a structural diagram of an ammonia engine crankcase exhaust gas treatment system according to the present invention. Detailed Implementation

[0014] To make the technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention:

[0015] like Figure 1 The diagram illustrates an ammonia engine crankcase exhaust gas treatment system. The ammonia engine 1 has an external crankcase interface 1.1 connected to an oil-gas separator 2, a throttle valve 3, and a blower 4. The oil-gas separator 2 separates engine oil from the crankcase exhaust gas. A pressure sensor 8 is installed between the external crankcase interface 1.1 and the oil-gas separator 2 to detect the crankcase pressure. After the blower 4 is started under the control of the controller 7, it extracts the exhaust gas from the crankcase and delivers it to the engine exhaust pipe 5, where it merges with the exhaust gas before entering the selective catalytic reduction (SCR) device 6. A throttle valve 3 is installed before the blower 4, its opening controlled by the controller 7 to prevent excessive extraction of exhaust gas from the crankcase and ensure that the crankcase pressure meets the engine's operating requirements. NOx sensors 9 for detecting NOx concentration are installed in the inlet and outlet pipelines of the SCR device 6.

[0016] A method for operating an ammonia engine crankcase exhaust gas treatment system specifically includes the following steps:

[0017] S1: After the controller 7 detects that the speed of the ammonia engine has reached the idle speed, the controller 7 powers on the fan 4 to start the fan 4;

[0018] S2: Controller 7 opens throttle valve 3. At the same time, controller 7 receives the crankcase pressure signal collected by pressure sensor 8. Controller 7 adjusts the opening of throttle valve 3 in real time according to the preset crankcase pressure value to keep the crankcase pressure at the preset value.

[0019] S3: The controller 7 receives the NOx concentration collected by the NOx sensor 9 at the inlet and outlet of the selective catalytic reduction device 6. At the same time, the controller 7 calculates the amount of ammonia required by the selective catalytic reduction device 6 based on the engine's real-time speed, power and the difference between the inlet and outlet NOx concentrations.

[0020] S4: Controller 7 controls the amount of ammonia injected into the selective catalytic reduction device 6 to reduce NOx in the waste gas.

[0021] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method of operating an ammonia engine crankcase exhaust treatment system, characterized by: The ammonia engine crankcase exhaust treatment system comprises an ammonia engine (1), the ammonia engine (1) is connected with an oil-gas separator (2) through an engine crankcase external interface (1.1), an outlet of the oil-gas separator (2) is connected with one end of a throttle valve (3), the other end of the throttle valve (3) is connected with a fan (4), the fan (4) is connected with a selective catalytic reduction device (6) through an engine exhaust pipe (5), the throttle valve (3), the fan (4) and the selective catalytic reduction device (6) are electrically connected with a controller (7) respectively, the controller (7) controls the working state of the fan (4), the exhaust gas in the engine crankcase is extracted through the crankcase external interface (1.1), and after being converged with the engine exhaust pipe (5), the exhaust gas enters the selective catalytic reduction device (6); The controller (7) controls the opening degree of the throttle valve (3), so that when the fan (4) extracts the exhaust gas in the crankcase, the pressure in the crankcase meets the engine working requirement; A pressure sensor (8) for detecting the pressure in the crankcase is arranged on a connecting pipeline between the ammonia engine (1) and the oil-gas separator (2); NOx sensors (9) for detecting the NOx concentration are arranged on the inlet and outlet pipelines of the selective catalytic reduction device (6); The working method of the ammonia engine crankcase exhaust treatment system comprises the following steps: After the controller (7) detects that the rotating speed of the ammonia engine (1) reaches the idle speed, the fan (4) is started to work; The controller (7) opens the throttle valve (3) and receives the pressure signal of the crankcase collected by the pressure sensor (8), the controller (7) adjusts the opening degree of the throttle valve (3) according to the preset crankcase pressure value, and controls the pressure in the crankcase to keep at the preset value; The controller (7) receives the NOx concentration information of the inlet and outlet of the selective catalytic reduction device (6) transmitted by the NOx sensor (9), and according to the real-time rotating speed and power of the engine and the difference between the inlet and outlet NOx concentrations, the controller (7) calculates the required amount of the reducing agent ammonia of the selective catalytic reduction device (6), and sprays the reducing agent ammonia into the selective catalytic reduction device (6) to reduce the NOx in the exhaust gas.

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