Hydrogen Injection for SCR Exhaust Temperature Control
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Solution Overview
Problem
Current diesel engines face challenges in achieving the required exhaust gas temperatures for effective NOx reduction in SCR systems, as existing solutions for adjusting exhaust gas temperatures are costly and require significant modifications.
Innovation Solution
Controllably injecting hydrogen, methanol, or water into the oxidizer feed of a diesel engine to regulate exhaust temperatures within the desired range for efficient NOx conversion, improving combustion efficiency and reducing fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If externally powered reheating or turbocharger re-matching or exhaust gas by-pass is used to adjust exhaust gas temperature, then the required temperature for SCR system is achieved, but the system complexity and cost increase significantly
Solution Approach 1:
The patent uses hydrogen, methanol, or water as simple, inexpensive chemical substances to adjust exhaust temperature. These substances are injected in controlled amounts to provide rapid temperature adjustment without requiring complex mechanical systems like reheating equipment or turbocharger modifications.
Solution Approach 2:
The patent changes the chemical composition parameter of the exhaust gas by injecting hydrogen, methanol, or water. This chemical parameter change triggers exothermic reactions that directly affect the temperature parameter, providing a simple method to achieve the required temperature range for SCR operation.
2Temperature
If externally powered reheating or turbocharger re-matching or exhaust gas by-pass is used to adjust exhaust gas temperature, then the required temperature for SCR system is achieved, but the modification cost becomes prohibitively high
Solution Approach 1:
The patent employs inexpensive chemical substances (hydrogen, methanol, water) instead of expensive mechanical modifications. These substances can be injected using simple dosing equipment, avoiding the high costs associated with externally powered reheating systems or turbocharger re-matching modifications.
Solution Approach 2:
The injected substances (particularly hydrogen and methanol) undergo self-combustion or exothermic reactions within the exhaust stream, providing their own heat source without requiring external energy input systems. This eliminates the need for externally powered reheating equipment and associated costs.
3Temperature
If sufficient hydrogen is injected to raise exhaust temperature above predetermined value, then SCR system temperature requirement is met, but fuel consumption increases
Solution Approach 1:
The patent implements temperature monitoring and controlled injection rates to ensure that only the necessary amount of hydrogen, methanol, or water is injected to achieve the target temperature range. This feedback control prevents excessive injection that would unnecessarily increase fuel consumption.
Solution Approach 2:
The patent offers multiple chemical substance options (hydrogen, methanol, water) with different energy characteristics. By selecting the most appropriate substance for specific operating conditions, the system can achieve temperature adjustment with minimal impact on overall fuel consumption.
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
This method effectively raises or maintains exhaust temperatures to facilitate NOx conversion in SCR systems while enhancing engine efficiency and reducing fuel consumption, offering a cost-effective and efficient solution.
Implementation Method 1
The combustion apparatus comprises a fuel inlet configured to receive a feed of fuel, e.g. diesel fuel, to the engine, e.g. to a combustion chamber thereof. The method may comprise feeding a fuel to the combustion apparatus, e.g. to a combustion chamber thereof.
Implementation Method 2
The release of nitrogen oxides from a diesel engine exhaust can be reduced by using Selective Catalytic Reduction ('SCR') systems. Typically, an SCR system catalyses the conversion of nitrogen oxides, usually using urea or ammonia as a reductant, into nitrogen (N2) and water (H2O).
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An apparatus (10) for use with a combustion apparatus (20) and an associated Selective Catalytic Reduction ('SCR') device (30), comprises a temperature sensing device (40) configured to measure the temperature of an exhaust (25) from the combustion apparatus (20); and an injection unit (50) configured to inject hydrogen (51) into a feed (21) of oxidizer to the combustion apparatus (20). An amount of hydrogen is added to an oxidiser feed of the combustion apparatus sufficient to reach a temperature in the exhaust of at least about 270°C.