Hydrogen Generator Combustor Ignition Stability
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Solution Overview
Problem
Existing hydrogen generator systems face instability in combustor ignition due to low flow velocities of propane and butane, leading to difficulties in stable mixing with combustion air and potential oxygen shortages, which can result in unstable ignitability and carbon monoxide generation.
Innovation Solution
A method for the hydrogen generator that includes a supplementary air flow rate adjuster and controller to adjust the flow rate of supplementary air, ensuring stable combustor ignition by increasing apparent flow velocity without raising material gas concentration, and using detectors to optimize air flow based on material gas composition and temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the concentration of material gas supplied to the combustor is increased to facilitate ignition, then the ignitability of the combustor is improved, but the material gas may not be stably mixed with the combustion air and oxygen shortage may occur
Solution Approach 1:
The patent applies preliminary action by pre-mixing supplementary air with the material gas before it enters the combustor. This pre-mixing ensures that the material gas is already combined with adequate oxygen in the correct proportions before ignition occurs, preventing both poor ignitability and unstable mixing during combustion. The controller adjusts the flow rate of supplementary air in advance based on the type of material gas being used.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the flow rate of supplementary air based on the composition and properties of the material gas. When material gas with lower flow velocity (such as propane or butane) is detected, the system increases the supplementary air flow rate to ensure proper mixing and prevent oxygen shortage. This parameter adjustment resolves the contradiction between achieving reliable ignition and maintaining stable mixing.
2Reliability
If the flow rate of material gas is increased to increase concentration, then ignition becomes easier, but the flow velocity remains low due to high specific gravity causing poor diffusion
Solution Approach 1:
The patent uses supplementary air as an intermediary substance to bridge the gap between material gas and combustion air. This intermediary gas facilitates the mixing process by carrying the heavy material gas (propane or butane) into the combustor and ensuring it mixes properly with the main combustion air stream. The supplementary air acts as a carrier that overcomes the low flow velocity issue caused by the high specific gravity of the material gas.
Solution Approach 2:
The system changes the flow rate parameter of supplementary air based on the specific gravity and flow velocity characteristics of the material gas. For materials with high specific gravity like butane (3.63 times that of city gas), the supplementary air flow rate is increased to compensate for the low diffusion capability, ensuring adequate mixing without requiring the material gas itself to achieve high flow velocity.
3Speed
If supplementary air is added to increase flow velocity, then mixing improves, but the concentration of material gas decreases
Solution Approach 1:
The controller dynamically adjusts the flow rate of supplementary air based on the type of material gas being used and the required ignition conditions. By optimizing the supplementary air flow rate parameter, the system achieves the necessary apparent flow velocity for proper mixing while maintaining the material gas concentration within the optimal range for reliable ignition. The parameter adjustment balances both requirements rather than treating them as conflicting.
Solution Approach 2:
The system uses detectors to detect the composition and properties of the material gas, creating a informational copy of the gas characteristics. This detection information is then used by the controller to adjust the supplementary air flow rate, effectively copying the optimal mixing ratio based on the detected material gas type. This allows the system to maintain appropriate concentration levels while achieving the necessary flow velocity for mixing.
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 method stabilizes combustor ignition by improving diffusivity and mixing of gases, preventing carbon monoxide generation and maintaining reliable ignition determination across varying material gas compositions.
Implementation Method 1
a reformer (6) configured to generate a hydrogen-containing gas by a reforming reaction of a material gas
Implementation Method 2
a combustor (14) configured to burn the material gas
Implementation Method 3
the flow velocity of the propane is 0.36 time the flow velocity of the city gas, and the flow velocity of the butane is 0.28 time the flow velocity of the city gas. Therefore, in a case where the mass flow rate is the same, because of the low flow velocities of the propane and the butane, the combustion fuel hardly diffuses in the combustor
Data Source
Figure 1
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Figure 3
AI summary
A hydrogen generator (100) includes: a reformer (6) configured to generate a hydrogen-containing gas by a reforming reaction of a material gas; a combustor (14) configured to heat the reformer (6) by diffusion combustion of the material gas and combustion air; a supplementary air flow rate adjuster (16) configured to adjust the flow rate of supplementary air added to the material gas; and a controller (30) configured to control the supplementary air flow rate adjuster 16 such that the flow rate of a mixture gas of the material gas and the supplementary air becomes a predetermined value.