Integrated Desulfurization via Mild Hydrotreating 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 at higher temperature and pressure conditions required for ultra-low sulfur production, making conventional desulfurization methods costly and inefficient.
Innovation Solution
An integrated process combining mild hydrotreating with an oxidation reaction zone to separate and remove labile and refractory sulfur and nitrogen compounds, where hydrotreating converts easily removable compounds, and oxidation targets harder-to-remove aromatic compounds, followed by extraction and adsorption of oxidized products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If existing hydrotreating reactors are upgraded to operate at higher temperature and pressure conditions to achieve ultra-low sulfur production, then sulfur content in fuel is reduced to meet stringent specifications, but capital investment and operational costs increase substantially
Solution Approach 1:
The desulfurization process is segmented into two distinct stages: mild hydrotreating at existing reactor conditions to remove labile sulfur compounds, followed by oxidation treatment specifically targeted at refractory aromatic sulfur compounds. This segmentation allows each stage to be optimized independently, avoiding the need to upgrade existing reactors to harsh conditions while achieving ultra-low sulfur levels in the final product
Solution Approach 2:
The invention changes the operational parameters from conventional harsh hydrotreating conditions (high temperature and pressure) to mild hydrotreating conditions (lower temperature and pressure), followed by oxidation at controlled conditions. This parameter change enables the use of existing reactor infrastructure without substantial upgrades while achieving the required sulfur reduction to ultra-low levels
2Manufacturing precision
If conventional harsh oxidation conditions are used to remove refractory sulfur compounds, then sulfur content is reduced effectively, but fuel quality deteriorates due to harmful side reactions
Solution Approach 1:
The oxidation step is conducted under controlled mild conditions with specific oxidizing agents and catalysts, rather than using conventional harsh oxidation conditions. This parameter control achieves effective removal of refractory sulfur compounds while minimizing harmful side reactions that would degrade fuel quality, such as excessive ring opening or formation of unwanted byproducts
Solution Approach 2:
A catalyst is introduced as an intermediary to facilitate the oxidation of refractory sulfur compounds under milder conditions. The catalyst enables the oxidation reaction to proceed selectively at lower temperatures and with controlled oxidizing agents, reducing the formation of harmful side products while effectively removing sulfur from the fuel
3Manufacturing precision
If new high pressure hydrotreating units are constructed to meet ultra-low sulfur specifications, then sulfur content in fuel is reduced to required levels, but capital investment increases substantially
Solution Approach 1:
The process segments sulfur removal into mild hydrotreating (using existing infrastructure) followed by oxidation treatment (can be implemented as a separate, smaller unit). This avoids the need to construct new high-pressure hydrotreating facilities while achieving the same ultra-low sulfur output, substantially reducing capital investment requirements
Solution Approach 2:
The mild hydrotreating step performs preliminary removal of labile sulfur compounds before the oxidation step targets refractory compounds. This preliminary action reduces the overall burden on any single processing unit, enabling the use of existing facilities rather than requiring new high-capacity units
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 cost-effective and efficient reduction of sulfur and nitrogen levels in hydrocarbon fuels, minimizing capital and operational costs by optimizing existing equipment and avoiding harsh oxidation conditions that can harm fuel quality.
Implementation Method 1
contacting the hydrocarbon stream with a hydrotreating catalyst in a hydrotreating reaction zone under mild conditions
Implementation Method 2
the aromatic-rich fraction is contacted with an oxidizing agent to convert the refractory organosulfur and organonitrogen compounds
Implementation Method 3
the oxidized organosulfur and organonitrogen compounds are removed in a separation zone
Implementation Method 4
followed by extraction and adsorption of oxidized products
Data Source
AI summary
Reduction of sulfur-containing and nitrogen-containing compounds from hydrocarbon feeds is achieved by first contacting the entire feed with a hydrotreating catalyst in a hydrotreating reaction zone operating under mild conditions to convert the labile organosulfur and organonitrogen compounds. An extraction zone downstream of the hydrotreating reaction zone separates an aromatic-rich fraction that contains a substantial amount of the remaining refractory organosulfur and organonitrogen compounds. The aromatic-lean fraction is substantially free of organosulfur and organonitrogen compounds, since the non-aromatic organosulfur and organonitrogen compounds were the labile organosulfur and organonitrogen compounds which were initially removed by mild hydrotreating. The aromatic-rich fraction is oxidized to convert the refractory organosulfur and organonitrogen compounds to oxidized sulfur-containing and nitrogen-containing hydrocarbon compounds. These oxidized organosulfur and organonitrogen compounds are subsequently removed.