Integrated Hydroprocessing Reactor for Ultra-Low Sulfur Diesel
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Solution Overview
Problem
Current hydroprocessing methods for producing ultra low sulfur diesel face challenges such as the formation of recombinant mercaptans and the complexity or cost intensiveness of multistage reaction designs, particularly when aiming for sulfur levels below 10 ppm.
Innovation Solution
A multi-stage hydroprocessing system with integrated reactors that include a gas withdrawal zone, a separator zone, and a liquid zone with a catalyst bed, allowing for the separation and recycling of hydrogen sulfide and ammonia to maintain hydrogen concentration and prevent recombinant mercaptan formation, while eliminating the need for external high-pressure separators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional hydroprocessing methods are used to achieve ultra low sulfur diesel, then sulfur removal is accomplished, but recombinant mercaptans are formed and external high-pressure separators are required increasing complexity
Solution Approach 1:
The patent combines the separator zone and catalyst bed zone into a single integrated reactor vessel. The separator zone is positioned above the catalyst bed within the same reactor, eliminating the need for external high-pressure separators. This integration reduces equipment complexity while maintaining the ability to achieve ultra low sulfur content through continuous gas-liquid separation and catalytic treatment.
Solution Approach 2:
The reactor is divided into distinct functional zones: a separator zone for gas-liquid separation and a catalyst bed zone for catalytic treatment. This segmentation allows each zone to perform its specific function efficiently within the integrated reactor, preventing recombinant mercaptan formation through staged processing.
2Manufacturing precision
If multistage reaction designs are implemented to reduce sulfur below 10 ppm, then sulfur specification is met, but process cost and complexity increase
Solution Approach 1:
The patent merges multiple reaction stages into a single integrated reactor with multiple catalyst beds. The first catalyst bed performs initial hydrodesulfurization, the separator zone removes generated gases, and the second catalyst bed completes sulfur removal to below 10 ppm. This integration achieves multistage processing without the cost and complexity of multiple separate reactors and separators.
Solution Approach 2:
The integrated reactor enables continuous hydrodesulfurization processing through sequential catalyst beds and intermediate separation. Hydrogen sulfide is continuously removed between catalyst beds, preventing equilibrium limitations and maintaining high reaction rates throughout the process, achieving ultra low sulfur content in a single continuous operation.
3Productivity
If traditional hydroprocessing reactors are used, then hydrogenation reactions occur, but external separators are needed increasing volume and cost
Solution Approach 1:
The patent combines the separator zone and catalyst bed zone into a single reaction vessel. The separator zone is positioned above the catalyst bed, allowing gas-liquid separation to occur within the reactor itself. This eliminates the need for external high-pressure separators, reducing overall equipment volume while maintaining high reaction efficiency for hydrodesulfurization.
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 configuration effectively reduces sulfur content in diesel to less than 10 ppm, minimizes the formation of recombinant mercaptans, and reduces the volume and cost of catalyst beds, achieving ultra low sulfur diesel production with improved cetane number and operational efficiency.
Implementation Method 1
The liquid zone comprising a catalyst bed; and the integrated hydroprocessing reactor being adapted to receive the effluent from a previous stage hydroprocessing reactor at about the liquid zone, effect separation of the effluent into a gaseous material and a liquid material in the separator zone, effect contacting of the liquid material thus separated with the catalyst bed in the liquid zone to obtain a current stage effluent
Implementation Method 2
the integrated hydroprocessing reactor defining a gas withdrawal zone, a separator zone, a liquid zone and an effluent withdrawal zone in a top to bottom fashion; effect separation of the effluent into a gaseous material and a liquid material in the separator zone
Data Source
AI summary
A multi-stage hydrotreating process obtains ultra-low sulfur diesel boiling range hydrocarbon having less than 10 ppm sulfur with elimination of external hot high pressure separator and avoids the formation of recombinant mercaptans by removing excess hydrogen sulfide formed during hydroprocessing reaction. The process includes mixing a diesel boiling range hydrocarbon feedstock with hydrogen and sending to the first predominantly liquid phase hydroprocessing reaction stage. Effluent from the first hydroprocessing reaction stage is sent to first separator zone of open and empty space in the upper part of the second hydroprocessing reaction stage to flash off the dissolved reaction products hydrogen sulfide and ammonia. Liquid part of the effluent of first hydroprocessing reaction stage is passed to the second predominantly liquid phase hydroprocessing reaction stage. The process is repeated until the liquid product sulfur level of less than 10 ppm is attained and the liquid product is sent to further processing.