Char-Supported Catalyst for Raw Gas Cleaning
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Solution Overview
Problem
The existing methods for cleaning raw product gas from gasification processes, particularly those using low-rank carbonaceous materials, face challenges such as contamination with tarry residues, particulates, and volatile inorganic species, which lead to operational difficulties and nutrient loss, requiring effective and cost-efficient solutions for purification and nutrient retention.
Innovation Solution
A process and apparatus utilizing char or char-supported catalysts to reform tarry residues and remove particulates, with a heat exchange system using char or solid adsorbents to cool and filter the gas, thereby recovering heat and retaining inorganic nutrients for reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the raw product gas is scrubbed with liquid (water or biodiesel), then tarry residues and other undesirable species are removed, but the gas must be cooled down first causing species to condense, heat recovery becomes challenging due to deposition on heat exchanger surfaces, and liquid waste stream requires expensive treatment
Solution Approach 1:
The patent replaces the conventional liquid scrubbing system with a solid-based catalytic reforming system. Instead of using liquid scrubbers that require cooling and heat exchangers, the invention employs solid catalysts (such as olivine, peridot, or forsterite) in a fluidized bed reactor to reform tarry residues at high temperatures. This substitution eliminates the need for cooling down the gas and avoids deposition issues on heat exchanger surfaces, as the solid catalyst particles remain suspended in the gas stream throughout the reforming process.
2Object-affected harmful factors
If conventional scrubbing is used to remove tarry components, then these species are transferred into water creating liquid waste stream, but this requires expensive treatment and is not feasible in remote areas without suitable water sources
Solution Approach 1:
The patent implements a self-service approach where the solid catalyst particles continuously reform tarry residues in the gas stream, converting them into useful synthesis gas components (CO, H2, CH4). The catalyst particles themselves serve as the reactive medium, eliminating the need for external water sources or liquid waste treatment facilities. The system is entirely self-sufficient, operating on a dry basis that is particularly suited for remote locations where water availability is limited.
3Object-affected harmful factors
If inorganic species volatilise into the product gas during gasification, then they cause corrosion and erosion of turbine/engine components, but conventional cleaning methods transfer them to sludge or waste forms that cannot be returned to the field
Solution Approach 1:
The patent converts the harmful effect of inorganic species volatilization into a beneficial outcome. The solid catalyst particles not only reform tarry residues but also capture and retain volatile inorganic species (such as alkali and alkaline earth metals) on their surfaces. Instead of these nutrients being lost to sludge or waste streams, they remain associated with the solid catalyst particles which can be periodically removed and returned to agricultural land as nutrient-rich amendments, thus converting a potential harm into a beneficial nutrient recycling process.
4Object-affected harmful factors
If the raw product gas is cooled down for scrubbing operation, then tarry residues can be removed, but heat recovery becomes difficult due to unavoidable deposition on heat exchanger surfaces
Solution Approach 1:
The patent replaces the mechanical cooling and liquid scrubbing system with a thermal processing approach using solid catalysts. The gas is maintained at high temperatures throughout the reforming process, eliminating the need for cooling down. The solid catalyst particles in fluidized bed configuration provide continuous contact with the hot gas stream, enabling effective tarry residue removal without heat exchanger deposition. This approach preserves the thermal energy in the gas, which can be directly utilized in downstream applications such as combustion engines or turbines.
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 effectively reduces tarry residues and inorganic contaminants, recovers heat, and retains nutrients, minimizing waste streams and operational costs, while ensuring the long-term sustainability of biomass as a renewable energy source.
Implementation Method 1
contacting the raw product gas with a flow of catalyst under operating conditions in which tarry residues in the raw product gas are reformed
Implementation Method 2
the char or char-supported catalyst is gasified by the gasifying agents in the raw product gas such as H2O and CO2
Implementation Method 3
cooling the resulting product gas via heat exchange with a heat exchange medium in the presence of char or a solid adsorbent medium
Implementation Method 4
condensable organic and inorganic species remaining in the product gas condense and adsorb on the char or the solid adsorbent medium
Data Source
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AI summary
The present disclosure provides a process for cleaning raw product gas. The process comprises contacting the raw product gas with a flow of catalyst to reform organic contaminants and inorganic contaminants in the raw product gas and to remove particulates. Further, the process comprises cooling the resulting product gas via heat exchange with a heat exchange medium in the presence of char or a solid adsorbent medium to condense remaining organic contaminants and inorganic contaminants on the char or solid adsorbent medium and to filter out fine particulates.