Solid Ammonium Carbamate Exhaust Purification System
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Solution Overview
Problem
Existing exhaust gas purification systems using liquid urea face issues such as large storage requirements, low nitrogen oxide reduction efficiency, and system damage due to freezing, while solid urea systems require high thermal energy and produce by-products that cause blockages and reduce efficiency.
Innovation Solution
A solid ammonium salt-based system that eliminates the need for separate liquid storage and injection systems, using a module-type design with a lower thermal decomposition temperature, producing ammonia efficiently and preventing by-product formation, and ensuring continuous operation with a smaller energy footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If liquid urea is used for selective catalytic reduction, then nitrogen oxide purification efficiency is improved, but storage container volume and system complexity increase
Solution Approach 1:
The invention changes the physical state of the reducing agent from liquid to solid form. Solid ammonium carbamate is used instead of liquid urea, which eliminates the need for large storage containers and complex injection systems while maintaining the ability to produce ammonia for nitrogen oxide reduction
Solution Approach 2:
The invention utilizes phase transition by heating solid ammonium carbamate to decompose it into ammonia gas. The solid ammonium carbamate is heated in a reaction chamber, transitions to gaseous ammonia, and then injected into the exhaust stream for catalytic reduction of nitrogen oxides
2Volume of stationary object
If solid urea is used for selective catalytic reduction, then storage requirements are reduced, but thermal decomposition temperature increases energy consumption
Solution Approach 1:
The invention changes the chemical composition from solid urea to solid ammonium carbamate. This chemical parameter change results in a lower thermal decomposition temperature, reducing the energy input required for ammonia generation while maintaining solid-state storage advantages
3Productivity
If solid urea is thermally decomposed, then ammonia is produced, but by-products cause blockages and reduce system reliability
Solution Approach 1:
The invention changes the chemical substance from solid urea to solid ammonium carbamate. This chemical parameter change modifies the decomposition reaction to produce only ammonia and carbon dioxide, eliminating harmful by-products like isocyanic acid and cyanuric acid that cause blockages and system failures
Solution Approach 2:
The invention converts the decomposition process into a beneficial reaction that produces only harmless gases (ammonia and carbon dioxide). The decomposition of ammonium carbamate is designed to avoid harmful by-products, turning what would be a harmful process into a clean, reliable ammonia generation method
4Productivity
If liquid urea is used, then ammonia is produced for nitrogen oxide reduction, but freezing at low temperatures damages the system
Solution Approach 1:
The invention changes the physical state of the reducing agent from liquid to solid. Solid ammonium carbamate does not freeze at low temperatures like liquid urea, eliminating the risk of system damage during cold weather operation while still enabling ammonia production when heated
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 system achieves longer operational periods, higher ammonia production capacity, and prevents ammonia coagulation issues, ensuring continuous exhaust gas purification and reducing infrastructure needs.
Implementation Method 1
the solid ammonium salt is heated in a main reactor to produce ammonia
Implementation Method 2
a heating element to heat the solid ammonium salt
Data Source
AI summary
The present invention relates to a technology of reducing nitrogen oxide (NOx) which is harmful discharge gas discharged from an internal combustion engine or a combustor, and to an exhaust gas purification system which inputs solid ammonium salt such as ammonium carbamate or ammonium carbonate into a reactor, thermally decomposes and converts the solid ammonium salt into the ammonia by using engine cooling water, exhaust gas, or an electric heater, which are installed in the reactor, and reduces the nitrogen oxide included in the exhaust pipe on a selective catalytic reduction into nitrogen by injecting the ammonia by using a pressure regulator and a dosing valve.