Integrated Desulfurization via Fraction Segmentation and Oxidation
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Solution Overview
Problem
Existing hydroprocessing facilities struggle to meet stringent sulfur and nitrogen reduction standards in hydrocarbon fuels due to the difficulty in upgrading existing hydrotreating reactors to operate under severe conditions required for ultra-low sulfur production, making it costly and inefficient to remove refractory sulfur and nitrogen compounds.
Innovation Solution
An integrated process combining hydrotreating and oxidative desulfurization/denitrification, where the hydrocarbon stream is separated into aromatic-lean and aromatic-rich fractions, with the aromatic-lean fraction undergoing hydrotreating and the aromatic-rich fraction undergoing oxidation to convert refractory compounds into oxidized forms that can be easily removed, optimizing equipment use and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing hydrotreating reactors are upgraded to operate under severe conditions for ultra-low sulfur production, then sulfur reduction capability is improved, but equipment complexity and capital investment increase
Solution Approach 1:
The patent segments the hydrocarbon stream into aromatic-lean and aromatic-rich fractions based on aromatic content. The aromatic-lean fraction (containing labile sulfur compounds) is subjected to mild hydrotreating, while the aromatic-rich fraction (containing refractory sulfur compounds) is subjected to oxidation. This segmentation allows each fraction to be processed under optimized conditions, avoiding the need to upgrade existing hydrotreating reactors to severe operating conditions for the entire stream.
Solution Approach 2:
The patent applies different processing qualities to different fractions: mild hydrotreating conditions for the aromatic-lean fraction and oxidation conditions for the aromatic-rich fraction. This local quality approach allows the system to achieve ultra-low sulfur levels without subjecting all feedstock to severe hydrotreating conditions, thereby reducing equipment complexity and capital investment requirements.
2Ease of manufacture
If conventional hydrotreating is used to remove refractory sulfur and nitrogen compounds, then processing simplicity is maintained, but sulfur and nitrogen reduction efficiency deteriorates
Solution Approach 1:
The patent segments the removal of sulfur and nitrogen compounds into two distinct processes: mild hydrotreating for labile compounds and oxidation for refractory compounds. This segmentation maintains processing simplicity for each individual step while significantly improving overall reduction efficiency by targeting refractory compounds that conventional hydrotreating cannot effectively remove.
Solution Approach 2:
The patent introduces oxidation as an intermediary process between the hydrotreating step and the final product. The oxidation step converts refractory sulfur and nitrogen compounds into more removable forms, acting as a mediator that enhances the overall efficiency of sulfur and nitrogen reduction without requiring complex modifications to the original hydrotreating process.
3Manufacturing precision
If the entire hydrocarbon stream is subjected to oxidation, then refractory compound removal is improved, but energy consumption and operational costs increase
Solution Approach 1:
The patent segments the oxidation step to apply it only to the aromatic-rich fraction containing refractory sulfur and nitrogen compounds, rather than treating the entire hydrocarbon stream. This segmentation significantly reduces energy consumption and operational costs while maintaining effective removal of refractory compounds, as only the fraction requiring oxidation undergoes this energy-intensive process.
Solution Approach 2:
The patent applies partial action by oxidizing only the aromatic-rich fraction (containing refractory compounds) rather than the entire stream. This partial oxidation approach is sufficient to achieve the desired removal of refractory compounds while avoiding the excessive energy consumption and operational costs that would result from oxidizing the complete hydrocarbon stream.
4Ease of operation
If existing facilities operate under mild conditions, then operational ease is maintained, but sulfur reduction to ultra-low levels is insufficient
Solution Approach 1:
The patent segments the sulfur reduction process into two pathways: mild hydrotreating for the aromatic-lean fraction (maintaining operational ease) and oxidation for the aromatic-rich fraction (achieving ultra-low sulfur levels). This segmentation allows the system to maintain operational ease under mild conditions for the majority of the stream while achieving the required ultra-low sulfur reduction levels through the oxidation step.
Solution Approach 2:
The patent changes the processing parameters by introducing oxidation as a complementary process to mild hydrotreating. Instead of operating hydrotreating at severe conditions to achieve ultra-low sulfur levels, the system changes the approach by adding oxidation to handle refractory compounds, thereby maintaining operational ease while achieving the desired sulfur reduction level.
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 allows for efficient and cost-effective reduction of sulfur and nitrogen levels in hydrocarbon fuels by targeting different classes of compounds, minimizing equipment capacity and operational costs, and avoiding unnecessary oxidation of labile compounds, thus producing fuels with ultra-low sulfur and nitrogen content.
Implementation Method 1
contacting the aromatic-lean fraction with a hydrotreating catalyst in a hydrotreating reaction zone under mild operating conditions to remove labile organosulfur and organonitrogen compounds
Implementation Method 2
contacting the aromatic-rich fraction with an oxidizing agent and a metal catalyst in an oxidation reaction zone to convert the refractory organosulfur and organonitrogen compounds into oxidized organosulfur and oxidized organonitrogen compounds
Data Source
AI summary
Deep desulfurization of hydrocarbon feeds containing undesired organosulfur and organonitrogen compounds to produce a hydrocarbon product having low levels of sulfur-containing and nitrogen-containing compounds, is achieved by first subjecting the entire feed to an extraction zone to separate an aromatic-rich fraction containing a substantial amount of the refractory organosulfur and organonitrogen compounds and an aromatic-lean fraction containing a substantial amount of the labile organosulfur and organonitrogen compounds. The aromatic-lean fraction is contacted with a hydrotreating catalyst in a hydrotreating reaction zone operating under mild conditions to convert the labile organosulfur and organonitrogen compounds. The aromatic-rich fraction is oxidized to convert the refractory organosulfur and organonitrogen compounds to oxidized organosulfur and organonitrogen compounds. These oxidized organosulfur and organonitrogen compounds are subsequently removed, producing a stream containing reduced levels of organosulfur and organonitrogen compounds.