Ammonia Cracking Bypass for Cold-Start Hydrogen Generation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge of generating hydrogen efficiently on-board vehicles for use in internal combustion engines due to the endothermic nature of ammonia cracking, which requires heat that is difficult to provide with limited electrical supply, and the safety and control issues associated with hydrogen storage.
Innovation Solution
An on-board ammonia cracking system that includes an exhaust gas cracking unit and an electric cracking unit, with a bypass system to route ammonia to either unit based on exhaust gas temperature, utilizing valves and an electronic control unit to manage ammonia flow, ensuring efficient hydrogen production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If ammonia is used as fuel in internal combustion engines, then zero CO2 emissions are achieved, but combustion is inconsistent under low engine load and high engine speed operating conditions
Solution Approach 1:
The patent combines ammonia fuel with hydrogen fuel in a dual-fuel system. Ammonia provides zero CO2 emissions while hydrogen provides rapid combustion characteristics. The two fuels are merged in the combustion chamber to achieve both environmental benefits and reliable combustion performance across all operating conditions.
Solution Approach 2:
Hydrogen acts as an intermediary substance that facilitates ammonia combustion. The hydrogen burns rapidly and consistently, creating conditions that enable more reliable ammonia combustion. This intermediary approach allows ammonia to maintain its zero CO2 emission advantage while overcoming its slow combustion rate limitation.
2Quantity of substance
If hydrogen is stored in compressed tanks, then fuel availability is ensured, but safety issues and control problems arise
Solution Approach 1:
The system generates hydrogen on-board through an ammonia cracking unit that decomposes ammonia into hydrogen and nitrogen. This self-service approach eliminates the need for external hydrogen storage tanks, ensuring hydrogen availability while avoiding the safety risks associated with storing large quantities of compressed hydrogen.
Solution Approach 2:
The hydrogen storage function is segmented into two parts: ammonia is stored in a stable, safe manner in the ammonia tank, and hydrogen is generated on-demand through cracking when needed. This segmentation separates the storage safety concerns from the fuel availability requirements.
3Quantity of substance
If electrical heating is used for ammonia cracking, then hydrogen production is achieved, but energy consumption increases due to limited electrical supply
Solution Approach 1:
The patent merges the ammonia cracking function with the exhaust gas treatment system. The exhaust gas, which would otherwise be wasted, is used to provide thermal energy for the endothermic cracking reaction. This combination converts a waste resource into a useful function, reducing electrical energy consumption while maintaining hydrogen production.
Solution Approach 2:
The hot exhaust gas, which represents wasted energy, is converted into a beneficial thermal source for driving the ammonia cracking reaction. This transforms a harmful waste product into a useful resource, significantly reducing the electrical energy required for hydrogen production.
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
Facilitates efficient hydrogen production from ammonia without the need for additional storage tanks, addressing safety and control issues, and providing a reliable fuel source for internal combustion engines.
Implementation Method 1
an exhaust gas cracking unit... when the internal combustion engine is producing exhaust gas having a temperature sufficient to facilitate ammonia cracking
Implementation Method 2
an electric cracking unit coupled to the exhaust gas cracking unit... routes ammonia to the electric cracking unit when the internal combustion engine is not producing exhaust gas having a temperature sufficient to facilitate ammonia cracking
Implementation Method 3
U.S. patent application Ser. No. 18/241,321 entitled 'SYSTEMS AND METHODS FOR THE ON-BOARD CATALYTIC PRODUCTION OF HYDROGEN FROM PHASE-CONTROLLED GASEOUS AMMONIA'
Data Source
AI summary
The present invention relates, in general, to systems and methods for generating hydrogen from ammonia on-board vehicles, where the produced hydrogen is used as fuel source for an internal combustion engine. The present invention comprises an exhaust heat cracking unit and an electric cracking unit fluidly connected by a controllable bypass path. When exhaust heat from the engine is unavailable, the bypass path redirects the gaseous ammonia flow away from the unheated exhaust heat cracking unit and directly into the electric cracking unit. This configuration prevents the introduction of cold or partially condensed ammonia into the exhaust heat cracking unit passages, thereby mitigating condensation, volume expansion, and thermal stress that could otherwise result in structural damage or thermal shock within the exhaust heat exchanger. The system enables seamless transition between heat sources, ensuring safe and efficient operation across dynamic vehicle or operating and power conditions.