Ammonia-Fueled Engine Exhaust Purification With Catalyst Bypass
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Solution Overview
Problem
Conventional engine devices using ammonia as fuel face challenges in controlling the amount and ratio of nitrogen oxides and ammonia in exhaust gases, leading to the need for larger exhaust gas purification devices and poor exhaust gas properties.
Innovation Solution
An engine device with a selective reduction catalyst and an ammonia adsorption catalyst, along with bypass passages and switch valves, allows for controlled flow of exhaust gases to optimize the ratio of ammonia and nitrogen oxides, reducing the size of the purification system and improving exhaust gas quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the exhaust gas purification device is constructed based on the estimated maximum value of nitrogen oxides and ammonia, then the purification capability is ensured, but the capacity and size of the exhaust gas purification device are increased
Solution Approach 1:
The patent applies dynamics by making the exhaust gas purification system adjustable through a bypass passage and switch valve. The system can dynamically change its configuration between two states: (1) passing exhaust gas through both the ammonia adsorption catalyst and selective reduction catalyst for maximum purification, and (2) bypassing the ammonia adsorption catalyst when ammonia concentration is low. This dynamic adaptability allows the system to maintain purification capability while reducing the effective size and reducing agent consumption when full purification capacity is not needed.
Solution Approach 2:
The patent changes the operational parameters of the purification system based on detected ammonia concentration. When ammonia concentration exceeds a predetermined threshold, the system activates the ammonia adsorption catalyst pathway; when it remains below the threshold, the system switches to bypass mode. This parameter-based control optimizes the balance between purification effectiveness and system size utilization.
2Ease of operation
If ammonia is mixed and combusted with hydrogen to improve incombustibility, then the combustibility is improved, but the exhaust gas properties deteriorate
Solution Approach 1:
The patent converts the harmful effect of ammonia combustion (production of unburned ammonia and nitrogen oxides in exhaust gas) into a beneficial purification process. By providing an ammonia adsorption catalyst and selective reduction catalyst in the exhaust gas purification device, the system captures and converts the harmful exhaust components. The ammonia adsorption catalyst selectively adsorbs unburned ammonia, and the selective reduction catalyst converts nitrogen oxides into harmless substances, thereby transforming the original harmful exhaust into purified exhaust gas.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The engine device maintains compactness while ensuring good exhaust gas properties and minimizing the use of reducing agents, effectively purifying exhaust gases by optimizing the ratio of ammonia and nitrogen oxides.
Implementation Method 1
a selective reduction catalyst which reduces nitrogen oxides contained in the exhaust gas by a reducing agent
Implementation Method 2
an ammonia adsorption catalyst which adsorbs ammonia contained in the exhaust gas
Data Source
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AI summary
[Problem] Provided is an engine device which facilitates making a device compact, and which can maintain good exhaust gas properties, inhibit the amount of a used reducing agent, and purify the exhaust gas. [Solution] An engine device 1 is an engine device 1 comprising an engine 2 which is operated by a fuel containing at least ammonia, and comprises: an exhaust passage 4 through which the exhaust gas exhausted from the engine 2 is flowed in the exhaust direction; a selective reduction catalyst 6 which is provided in the exhaust passage 4 and reduces nitrogen oxides contained in the exhaust gas by a reducing agent; an ammonia adsorption catalyst 7 which is provided in the exhaust passage 4 on the upper stream side than the selective reduction catalyst 6 in the exhaust direction, and adsorbs ammonia contained in the exhaust gas; a first bypass passage 8 which is connected to the exhaust passage 4 to bypass the ammonia adsorption catalyst 7; and a first path switch valve 9 which is provided on the upper stream side than the ammonia adsorption catalyst 7 in the exhaust direction and switches whether the flow of the exhaust gas is passed through the ammonia adsorption catalyst 7 or not.