Fuel Cell System By-Product Gas Purification and Reformer Operation
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Solution Overview
Problem
The existing methods for treating landfill gas to purify methane for fuel cells are complex, costly, and inefficient, leading to substantial losses and the need for additional fuel sources to prevent pollution, as they require high levels of impurity removal and catalyst poisoning prevention.
Innovation Solution
A method for operating a fuel cell system that separates by-product gases into purified and residual streams, where the purified stream is used as fuel for the reformer and the residual stream is used to supplement the combustor, optimizing system efficiency and reducing the need for high-purity fuel recovery, allowing for endothermic reforming and lower energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high levels of impurity removal are implemented to purify landfill gas for fuel cells, then fuel purity is improved, but system complexity and cost increase substantially
Solution Approach 1:
The purification system is segmented into multiple functional units including a condenser for water removal, an adsorber for sulfur compound removal, and a filter for particulate removal. Each unit targets specific impurities, allowing the system to achieve high fuel purity through modular, manageable stages rather than a single complex purification process.
Solution Approach 2:
The patent introduces intermediate storage and processing stages between the landfill gas source and the fuel cell stack. The gas passes through intermediate purification units (condenser, adsorber, filter) that act as mediators to progressively remove impurities. This intermediary approach allows complex purification to be broken down into simpler, more manageable steps.
2Reliability
If extensive purification treatment is applied to remove sulfur compounds and other contaminants, then catalyst poisoning is prevented, but operational cost and time increase
Solution Approach 1:
The purification units (condenser, adsorber, filter) are positioned upstream in the system to remove impurities before the gas reaches the fuel cell stack and catalyst. This preliminary action prevents catalyst poisoning before it can occur, rather than requiring complex post-treatment or frequent catalyst regeneration, thereby reducing operational time losses.
Solution Approach 2:
The patent converts potentially harmful impurities in landfill gas into manageable removal tasks. By designing dedicated removal units for specific contaminants (water condenser, sulfur adsorber, particulate filter), the system transforms the harmful presence of these substances into a structured, efficient purification process that protects the catalyst without excessive time or cost penalties.
3Object-affected harmful factors
If complete impurity removal is required to prevent pollution, then environmental protection is improved, but additional fuel sources are needed for flaring waste gas
Solution Approach 1:
The patent recovers and utilizes the waste gas stream containing removed impurities and contaminants. Instead of flaring this gas with additional fuel, the system captures it through the purification units and redirects it to a flare system that can burn the concentrated contaminants efficiently. This recovers the energy value of the waste gas and reduces the need for additional fuel sources while maintaining environmental protection.
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 approach increases fuel-to-electric efficiency, reduces energy requirements, and minimizes losses by utilizing residual gas as supplemental fuel, eliminating the need for flaring and lowering the cost of gas purification, while maintaining system reliability on lower quality fuels.
Implementation Method 1
adsorbing the water vapor and heavier hydrocarbon fractions to form a dried gas stream
Implementation Method 2
cooling the resultant gas to condense the water vapors and heavier hydrocarbons
Implementation Method 3
endothermic steam reforming occurs in the fuel reformer
Implementation Method 4
A portion of the anode tail gas is supplied to the combustor and is combusted with depleted air from the cathode tail gas
Implementation Method 5
The hot effluent from the combustor is then passed through the heat exchanger to add heat to the reforming process
Implementation Method 6
Oxygen ions from the air migrate from the cathode layer through the dense electrolyte to the anode layer in which it reacts with the H2 and CO in the fuel, forming water and CO2, and thereby creating an electrical potential
Data Source
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AI summary
A method of operating a fuel cell system on a by-product gas containing a fuel constituent. The fuel cell system includes a fuel reformer for forming a reformate stream, a combustor for supplying heat energy to the fuel reformer, and a fuel cell stack. The method includes the steps of separating a by-product gas into a purified gas stream and a residual stream with a gaseous fuel purifier, feeding the purified gas stream to the fuel reformer configured to transform the purified gas stream to produce a reformate stream, and feeding the residual gas stream to a combustor configured to provide heat energy to the fuel reformer. The purified gas stream contains a higher concentration of preferable fuel constituents and a lower concentration of contaminants than the residual gas stream.