Hydrogen Generator Combustion Stability via Valve Control
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Solution Overview
Problem
Hydrogen generating apparatuses face instability in combustion due to pressure fluctuations and controllability issues with combustion air flow, leading to increased carbon monoxide concentrations or extinguishment, particularly during ignition and startup processes.
Innovation Solution
Incorporating a controller to adjust the opening of a first valve in the cooling channel, which controls the amount of combustion air fed to a cooler, thereby stabilizing the combustion process by managing pressure loss and temperature of the hydro-desulfurizer, ensuring it operates within optimal temperature ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat exchanger is provided to cool the hydro-desulfurizer by circulating air, then the hydro-desulfurizer can be kept at an appropriate temperature, but pressure fluctuation occurs in the combustion space and combustion air channel due to unstable combustion condition
Solution Approach 1:
A temperature detection unit is introduced as an intermediary to monitor the hydro-desulfurizer temperature and provide feedback to the control unit. This enables precise control of the air flow rate through the first valve, allowing the system to maintain appropriate temperature while avoiding the instability issues caused by manual or indirect control methods
Solution Approach 2:
The system implements a feedback control mechanism where the temperature detection unit continuously monitors the hydro-desulfurizer temperature and feeds this information back to the control unit. The control unit then adjusts the first valve to maintain the temperature within the optimal range (200-300°C), resolving the contradiction between temperature control and combustion stability
2Quantity of substance
If the temperature of the hydro-desulfurizer is lower than the lowest temperature, then the adsorption capacity significantly decreases, but conversely, when the temperature is higher than the highest temperature, the hydro-desulfurizing agent is thermally degraded
Solution Approach 1:
The control unit dynamically adjusts the air flow rate parameter to the first valve based on temperature feedback, maintaining the hydro-desulfurizer temperature within the optimal range (200-300°C). This parameter control prevents both insufficient adsorption capacity at low temperatures and thermal degradation at high temperatures
Solution Approach 2:
The temperature detection unit provides continuous feedback on the hydro-desulfurizer temperature to the control unit, which then adjusts the cooling air flow rate to maintain the temperature within the optimal range, preventing both low-temperature adsorption failure and high-temperature thermal degradation
3Device complexity
If the opening of the first valve is not controlled, then the structure is simple, but excess and deficiency of combustion air feed or oscillation of combustion flame occurs
Solution Approach 1:
A feedback control system is implemented where the temperature detection unit monitors hydro-desulfurizer temperature and the control unit adjusts the first valve accordingly. This feedback mechanism prevents combustion instability while maintaining reasonable structural complexity
Solution Approach 2:
The control system automatically adjusts the first valve based on temperature feedback without requiring manual intervention. The system serves itself by autonomously maintaining optimal operating conditions, preventing combustion oscillation and improving reliability
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 configuration stabilizes combustion, reduces pressure fluctuations, and prevents excessive carbon monoxide production or extinguishment, allowing for efficient and stable operation of the hydrogen generating apparatus.
Implementation Method 1
a hydro-desulfurizer (3) for removing a sulfur component in a feed stock by hydrogenation reaction
Implementation Method 2
a cooler (14) for cooling the hydro-desulfurizer (3) by circulating air
Implementation Method 3
a method of combusting a fuel offgas from a fuel cell with a combustor
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A hydrogen generating apparatus (1) includes a reformer (6) for reforming a feed stock containing hydrocarbon to generate a hydrogen-containing gas, a combustor (7) for heating the reformer (6) by combusting a combustion gas which is the feed stock or the hydrogen-containing gas and air, and an air feeder (9) for feeding the air to the combustor (7). The hydrogen generating apparatus (1) also includes a combustion air channel (10) for connecting the combustor (7) and the air feeder (9), a hydro-desulfurizer (3) for removing a sulfur component in the feed stock by hydrogenation reaction, and a cooler (14) for cooling the hydro-desulfurizer (3) by circulating the air. Further, the hydrogen generating apparatus (1) includes a contraction part (17), a cooling channel (15) joining downstream the contraction part (17), and a first valve (16) disposed in the cooling channel (15). Further, the hydrogen generating apparatus (1) includes a controller (13) configured to control an opening of the first valve (16) to be increased at a predetermined timing.