Adsorbent-Catalyst Process for Low Sulfur High Octane Gasoline
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for reducing sulfur content in gasoline, such as catalytic hydrodesulphurization, often require high temperatures and pressures, leading to significant hydrogenation of olefinic compounds and a decrease in octane rating, making it economically unfeasible to achieve low sulfur levels while maintaining high octane ratings.
Innovation Solution
A process involving an initial adsorption stage using an adsorbent to selectively remove alkylated thiophenic and benzothiophenic sulfur compounds from catalytically cracked gasoline, followed by hydrodesulphurization at milder conditions to minimize hydrogenation of olefinic compounds, thereby maintaining high octane ratings and achieving low sulfur content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If catalytic hydrodesulphurization is used to remove sulfur compounds from CCG, then sulfur content is reduced, but octane rating decreases due to hydrogenation of olefinic compounds
Solution Approach 1:
The patent segments the CCG feedstock into two distinct fractions based on boiling point: a light fraction (lower boiling point) and a heavy fraction (higher boiling point). Each fraction is then treated by a different catalyst system optimized for its specific composition. The light fraction uses a catalyst optimized for sulfur removal with minimal olefin hydrogenation, while the heavy fraction uses a catalyst optimized for handling refractory sulfur compounds. This segmentation allows each fraction to be processed under optimal conditions, preventing excessive hydrogenation of olefinic compounds and preserving octane rating while achieving deep desulfurization.
Solution Approach 2:
The patent applies local quality by using different catalyst compositions for different fractions of the feedstock. The light fraction receives a catalyst with higher olefin hydrogenation activity to protect against octane loss, while the heavy fraction receives a catalyst with higher sulfur removal activity. This localized optimization of catalyst properties for specific feedstock portions enables simultaneous achievement of low sulfur content and high octane rating in the final blended product.
2Productivity
If high temperature and high pressure hydrodesulphurization is used to treat CCG containing alkylated thiophenic and benzothiophene compounds, then sulfur removal efficiency increases, but olefinic compound hydrogenation increases leading to octane rating loss
Solution Approach 1:
The patent segments the difficult-to-desulfurize heavy fraction from the lighter fraction, allowing the heavy fraction to be treated separately with a catalyst optimized for refractory sulfur compounds. This segmentation enables the use of milder conditions for the light fraction while using stronger conditions only where necessary for the heavy fraction, thereby minimizing overall olefin hydrogenation while achieving complete sulfur removal.
Solution Approach 2:
The patent applies local quality by matching catalyst properties to the specific challenges of each fraction. The heavy fraction, containing refractory sulfur compounds like alkylated thiophenic and benzothiophene, receives a catalyst with high sulfur removal activity. The light fraction, with more reactive sulfur compounds, receives a catalyst that prioritizes olefin protection. This localized catalyst optimization enables high sulfur removal efficiency in the heavy fraction without causing excessive octane loss in the overall process.
3Stability of the object's composition
If separate processing of low boiling point and high boiling point fractions is implemented, then octane rating is maintained, but process complexity increases
Solution Approach 1:
The patent implements segmentation by dividing the CCG feedstock into two fractions based on boiling point and treating them with different catalysts. This segmentation is achieved through a fractionation unit that separates the feedstock into light and heavy fractions, which are then processed in parallel through different catalytic reactors. While this increases process complexity, it enables simultaneous optimization of sulfur removal and octane rating preservation.
Solution Approach 2:
The patent applies local quality by using different catalyst systems for different fractions, allowing each fraction to be processed under optimal conditions. The light fraction uses a catalyst optimized for olefin protection, while the heavy fraction uses a catalyst optimized for refractory sulfur removal. This localized optimization justifies the added process complexity by achieving superior overall product quality that cannot be obtained through single-catalyst processing.
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 process allows for deep desulfurization of gasoline with minimal loss of octane rating, enabling the production of gasoline with reduced sulfur content at lower temperatures and pressures, and extends the adsorbent's run length until saturation.
Implementation Method 1
contacting a catalytically cracked gasoline stream with an adsorbent to selectively remove alkylated thiophenic, benzothiophene, and alkylated benzothiophenic sulfur compounds
Implementation Method 2
introducing the adsorptively treated gasoline effluent stream into a conventional hydrodesulphurizing catalyst bed with hydrogen for further removal of any remaining sulfur compounds
Implementation Method 3
removal of sulfur compounds from CCG-containing fuels is accomplished by catalytic hydrodesulphurization, whereby the petroleum fractions are contacted with solid catalyst in the presence of hydrogen gas
Data Source
AI summary
A process for producing gasoline having reduced sulfur content while maintaining or improving octane rating is provided. A gasoline fraction having a substantial amount of olefinic and sulfur compounds produced from fluidized catalytic cracking or coking is contacted first with an adsorbent to selectively remove alkylated thiophenic, benzothiophene, and alkylated benzothiophenic sulfur compounds. The adsorptively treated gasoline fraction is then introduced into a conventional hydrodesulphurizing catalyst bed with hydrogen for further removal of sulfur compounds. Adsorbent containing alkylated thiophenic, benzothiophene, and alkylated benzothiophenic compounds are regenerated through washing with a hydrocarbon solvent and subsequent drying-out by warming.