Hydrogen-Enriched Feedstock for FCC Desulfurization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current hydrocarbon fuel processing technologies face challenges in efficiently and economically removing refractory sulfur compounds, leading to high costs and yield losses, especially in meeting stringent sulfur specifications for ultra-low sulfur content fuels.
Innovation Solution
A process that enriches liquid hydrocarbon feedstocks with hydrogen, dissolving it in the feedstock and flashing off excess gas, allowing for efficient desulfurization and denitrification reactions in a fluidized catalytic cracking system, utilizing existing refinery units with minimal modifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional hydrocracking processes are used to remove sulfur compounds, then sulfur content is reduced, but high pressure (150 kg/cm2 or greater) and high catalyst inventory are required, increasing equipment complexity and operating costs
Solution Approach 1:
The patent changes the pressure parameter from conventional hydrocracking high pressure (150 kg/cm2 or greater) to atmospheric or near-atmospheric pressure operation. This parameter change allows the process to achieve sulfur removal without requiring high-pressure equipment, thereby reducing equipment complexity while maintaining the beneficial effect of sulfur content reduction
Solution Approach 2:
The patent employs a disposable catalyst bed that is replaced rather than regenerated. This eliminates the need for complex catalyst regeneration systems and high-pressure equipment, achieving sulfur removal with simpler, less expensive equipment while the catalyst serves its function and is then discarded
2Reliability
If fixed bed hydrocracking is used to achieve long runs and high on-stream reliability, then reliability is improved, but high pressure operation and large catalyst inventory are required, increasing operating costs
Solution Approach 1:
The patent employs a self-service approach where the catalyst bed is designed to be replaced in-situ without requiring catalyst regeneration equipment or large catalyst inventories. The system serves itself by allowing direct catalyst replacement at atmospheric pressure, achieving reliability without the need for maintaining large catalyst stocks or complex regeneration systems
Solution Approach 2:
The patent changes the operating pressure parameter to atmospheric or near-atmospheric conditions, which allows for simplified equipment and reduced catalyst inventory while maintaining on-stream reliability through straightforward catalyst replacement procedures
3Device complexity
If fluidized catalytic cracking is used to operate at low pressure, then equipment complexity is reduced, but the process cannot upgrade hydrocarbon product by hydrogenation and requires high reaction temperatures that accelerate coke formation
Solution Approach 1:
The patent introduces hydrogen gas as an intermediary substance that dissolves in the liquid hydrocarbon feedstock to form a hydrogen-enriched liquid phase. This hydrogenated liquid phase then contacts the catalyst at low temperatures, enabling hydrogenation reactions without requiring high-temperature operation, thus reducing coke formation while maintaining simple equipment
Solution Approach 2:
The patent changes the reaction temperature parameter from conventional high temperatures (650-700°C) to lower temperatures (below 540°C), and introduces hydrogen concentration as a new controlling parameter. This allows the process to achieve both hydrogenation and cracking at low temperatures, minimizing coke formation while keeping equipment simple
4Productivity
If high reaction temperatures are used in FCC to convert hydrocarbons, then conversion efficiency is improved, but coke formation increases, reducing liquid hydrocarbon product yield
Solution Approach 1:
The patent uses dissolved hydrogen as an intermediary that provides hydrogen atoms for cracking reactions at lower temperatures. This hydrogen-enriched liquid feedstock enables efficient hydrocarbon conversion without requiring high temperatures, thereby maintaining high conversion efficiency while minimizing coke formation and preserving liquid hydrocarbon product yield
Solution Approach 2:
The patent changes the temperature parameter from high (650-700°C) to low (below 540°C) and introduces hydrogen concentration as a controlling parameter. This parameter change allows the system to achieve high conversion efficiency through hydrogen-assisted cracking at low temperatures, preventing the temperature-induced coke formation that would otherwise reduce liquid product yield
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 enhances hydrocarbon product quality and yield while reducing sulfur and nitrogen content, minimizing equipment additions and operating costs, and effectively addressing the removal of refractory sulfur compounds.
Implementation Method 1
mixing the liquid hydrocarbon feedstock and an excess of hydrogen gas in a mixing zone to dissolve a portion of the hydrogen gas in the liquid hydrocarbon feedstock to produce a hydrogen-enriched liquid hydrocarbon feedstock
Implementation Method 2
introducing the hydrogen-enriched liquid hydrocarbon feedstock and remaining hydrogen into a flashing zone in which at least a portion of undissolved hydrogen gas is flashed
Implementation Method 3
separating the reaction products, including removing hydrogen sulfide from the reaction products
Data Source
AI summary
A process for catalytically cracking a hydrocarbon oil containing sulfur and/or nitrogen hydrocarbon constituents by dissolving excess hydrogen in the liquid hydrocarbon feedstock in a mixing zone at a temperature of 420° C. to 500° C. and a hydrogen-to-feedstock oil volumetric ratio of 300:1 to 3000:1, flashing the mixture to remove remaining hydrogen and any light components in the feed, introducing the hydrogen saturated hydrocarbon feed into an FCC reactor for contact with a catalyst suspension in a riser or downflow reactor to produce lower boiling hydrocarbon components which can be more efficiently and economically separated into lower molecular weight hydrocarbon products, hydrogen sulfide and ammonia gas and unreacted hydrogen in a separation zone. Hydrogen present in the liquid phase enhances the desulfurization and denitrification reactions which occur during the conversion process and allows for the removal of significantly more sulfur- and/or nitrogen-containing contaminants from the feedstock in an economical fashion.