Gas Engine Catalyst Activation via Lower-Energy Agent
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Solution Overview
Problem
Natural gas engines face challenges in activating catalysts at an early stage after cold start due to the higher activation energy required for catalytic reactions of hydrocarbons with small carbon numbers, such as methane, which slows down the catalytic reaction rate.
Innovation Solution
A gas engine system that includes a catalyst in the exhaust system, a temperature detector, a catalyst activating device, and a controller to supply an activation promoting agent with lower activation energy, adjusting intake air, oxygen concentration, and fuel injection to decrease the excess air ratio and facilitate catalyst activation by promoting a catalytic reaction that increases the catalyst temperature quickly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a catalyst is set in the exhaust system of a natural gas engine, then uncombusted fuel gas can be oxidized more efficiently at high temperatures, but the catalyst cannot be activated promptly after cold start due to high activation energy requirements
Solution Approach 1:
The patent introduces an activation promoting agent as an intermediary substance that facilitates the activation of the catalyst. This agent has lower activation energy requirements than the main fuel gas, allowing it to initiate catalytic reactions at lower temperatures and generate heat to warm up the catalyst quickly after cold start, thereby enabling the catalyst to reach its optimal working temperature faster and improve both activation speed and purifying performance
Solution Approach 2:
The patent changes the chemical parameters of the exhaust gas by adding an activation promoting agent with different combustion characteristics. This agent has lower activation energy and different reactivity compared to the main fuel gas, allowing the catalytic reaction to proceed at lower temperatures during cold start, thus enabling catalyst activation without requiring high initial temperatures
2Temperature
If fuel injection is performed to supply uncombusted fuel and oxygen to the exhaust passage for catalyst activation, then catalyst temperature increases, but the catalytic reaction rate remains low due to high activation energy of methane
Solution Approach 1:
The activation promoting agent serves as a mediator that bridges the gap between the cold catalyst state and the high-temperature catalytic reaction. By having lower activation energy, it can react more readily at lower temperatures, generating heat to raise the catalyst temperature while also demonstrating that the catalytic reaction can proceed at lower temperatures with the right chemical conditions, thus improving both temperature increase efficiency and reaction rate
Solution Approach 2:
The patent changes the chemical composition parameters of the exhaust gas by introducing an activation promoting agent with different combustion properties. This agent has lower activation energy and different reactivity compared to methane, allowing the system to achieve both temperature increase and acceptable reaction rates by operating at different chemical parameter conditions than the main fuel gas alone
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 effectively activates the catalyst at an earlier stage by utilizing a catalytic reaction with an activation promoting agent, ensuring the catalyst reaches its optimal temperature range more quickly, enhancing its purifying performance.
Implementation Method 1
a catalyst converter (6) provided on a passage between the exhaust gas outlet (41) of the exhaust pipe (4) and the exhaust gas inlet (53) of the turbocharger (5); catalysts (65) which oxidize uncombusted fuel gas contained in exhaust gas discharged from the gas engine (2)
Implementation Method 2
the activation promoting agent contains a first activation promoting agent containing a hydrocarbon that has a less activation energy value for a catalytic reaction catalyzed by the catalysts (65) than the fuel gas of the gas engine (2)
Implementation Method 3
a gas engine (2) that combusts fuel gas
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A gas engine system includes: a gas engine; an exhaust pipe through which exhaust gas discharged from the gas engine flows; a turbocharger connected to the exhaust pipe; a catalyst that oxidizes uncombusted fuel gas in the exhaust gas of the gas engine; a temperature sensor configured to measure a temperature of the catalyst; a catalyst activating device configured to supply an activation promoting agent that promotes activation of the catalyst to a passage extending from the exhaust pipe to the catalyst; and an engine controller. The activation promoting agent contains a hydrocarbon that has a less activation energy value for a catalytic reaction catalyzed by the catalyst than the fuel gas of the gas engine.