CO2-to-SPK Process Using RWGS and Hydroisomerization
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Solution Overview
Problem
The aviation sector's high carbon emissions and the high cost of sustainable aviation fuel (SAF) compared to fossil fuel-based jet fuel, along with the challenges of blending traditional Fischer-Tropsch (F-T) kerosene into SPK due to its high n-alkane content, necessitate an efficient and economical process to produce synthetic paraffinic kerosene (SPK) using low-carbon hydrogen and captured CO2.
Innovation Solution
A process involving electrolysis of water using renewable electricity to produce hydrogen and oxygen, followed by a Reverse Water Gas Shift (RWGS) reaction to convert CO2 into carbon monoxide, which is then used in a Liquid Fuel Production (LFP) reactor to generate n-alkanes. These n-alkanes are processed through hydroisomerization, oligomerization, and hydrocracking to produce branched alkanes meeting SPK specifications, with a carbon intensity as low as zero.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional Fischer-Tropsch process is used to produce kerosene, then the process can generate jet fuel components, but the high n-alkane content in the product limits blending into semi-synthetic jet fuel
Solution Approach 1:
The patent applies parameter changes by modifying the Fischer-Tropsch process conditions (temperature, pressure, catalyst type) to alter the chemical composition of the produced kerosene. Specifically, it uses cobalt-based catalysts and optimizes reaction parameters to reduce n-alkane content and increase iso-alkane content, thereby improving blending compatibility while maintaining production volume
Solution Approach 2:
The patent introduces an intermediary hydroprocessing unit between the Fischer-Tropsch reactor and the blending stage. This intermediary unit performs hydrocracking and hydroisomerization to further modify the kerosene composition, converting high n-alkane content into more blendable iso-alkane structures, thus resolving the blending compatibility issue
2Object-generated harmful factors
If sustainable aviation fuel is produced from low-carbon hydrogen and CO2, then carbon emissions are reduced, but the production cost is significantly higher than fossil fuel-based jet fuel
Solution Approach 1:
The patent applies self-service by utilizing CO2 that is already captured from industrial processes or atmospheric sources as a feedstock, rather than requiring additional carbon input. The system uses this available CO2 combined with low-carbon hydrogen to produce SAF, thereby reducing overall carbon emissions while managing production costs through efficient use of available resources
Solution Approach 2:
The patent optimizes process parameters including temperature, pressure, and catalyst selection to maximize the efficiency of converting CO2 and hydrogen into fuel. By using cobalt-based catalysts and optimizing the Fischer-Tropsch conditions, the system improves conversion efficiency and reduces operational costs, making the high-carbon-intensity fuel more economically viable
3Manufacturing precision
If hydroisomerization is applied to convert n-alkanes to iso-paraffins, then blending performance is improved, but additional processing steps and costs are required
Solution Approach 1:
The patent merges the hydroisomerization step with the existing hydroprocessing unit that already performs hydrocracking. By combining these functions into a single integrated unit with appropriate catalyst beds, the system achieves both hydrocracking and hydroisomerization in one stage, improving blending performance while minimizing the increase in processing steps and operational complexity
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 process achieves a kerosene selectivity of 50-100% and produces SPK with a carbon intensity of 0-10%, meeting jet fuel specifications and significantly reducing aviation emissions.
Implementation Method 1
Renewable or low carbon electricity is used in an electrolyzer to convert water to hydrogen and oxygen
Implementation Method 2
Carbon dioxide is reacted with at least a portion of the hydrogen to produce a stream comprising carbon monoxide
Implementation Method 3
The catalytic hydrogenation of carbon monoxide to produce light gases, liquids, and waxes, ranging from methane to heavy hydrocarbons (C100 and higher) in addition to oxygenated hydrocarbons, is typically referred to Fischer-Tropsch (or F-T) synthesis
Implementation Method 4
The invention overcomes this issue and concentrates on the 'straight run kerosene' but via hydroisomerization, thereby overcoming the issues of blending straight run F-T kerosene into the SPK. The hydroisomerization converts the n-alkanes to iso-paraffins
Implementation Method 5
These F-T waxes are then hydrocracked and/or further processed to produce diesel, naphtha, and other fractions
Data Source
AI summary
A process for the production of sustainable aviation fuel (SAF) with low carbon intensity. The jet fuel is produced from the reaction of hydrogen from the electrolysis of water with captured carbon dioxide. The hydrogen and carbon dioxide are reacted to product a stream comprising carbon monoxide. Hydrogen and carbon monoxide are reacted to produce n-alkanes. Alkanes are hydroisomerized to produce sustainable aviation fuel with low carbon intensity.