Liquid-full Hydrotreating and Dewaxing Middle Distillate
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Solution Overview
Problem
Conventional hydroprocessing methods for producing low-sulfur and ultra-low-sulfur diesel fuels with improved cold flow properties are inefficient, requiring large quantities of hydrogen, expensive equipment, and result in catalyst deactivation due to coke formation and vulnerability to sulfur and nitrogen contaminants.
Innovation Solution
A liquid-full hydroprocessing process that dissolves hydrogen in a middle distillate fuel feedstock with a diluent, allowing for hydrotreating and dewaxing in a single phase without separate hydrogen recycling, using a zeolite catalyst that tolerates sulfur and nitrogen, thereby reducing sulfur and nitrogen content and improving cold flow properties without additional hydrogen and minimizing catalyst deactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional trickle bed reactors are used for hydroprocessing, then sulfur and nitrogen can be removed from diesel fuel, but large quantities of hydrogen are required and expensive hydrogen recycling equipment is needed
Solution Approach 1:
The invention changes the physical state of hydrogen from gas phase to dissolved liquid phase by controlling hydrogen solubility parameters in the hydrocarbon feed. This parameter change allows hydrogen to be supplied in solution without requiring gas compression and recycling equipment, directly reducing both hydrogen consumption and device complexity
Solution Approach 2:
The invention uses hydraulic principles by dissolving hydrogen in the liquid hydrocarbon feed to create a homogeneous liquid mixture. This eliminates the need for pneumatic hydrogen gas circulation systems, removing expensive compressors and recycling equipment while maintaining effective hydrogen supply for the hydroprocessing reactions
2Reliability
If conventional trickle bed reactors are used for hydroprocessing, then hydrocarbon feed can be treated, but significant coke formation occurs on catalyst surface leading to catalyst deactivation
Solution Approach 1:
The invention changes the reaction medium from gas-liquid two-phase to liquid-full single phase by dissolving hydrogen in the hydrocarbon feed. This parameter change prevents coke formation by ensuring uniform hydrogen distribution and avoiding localized carbon deposition, thereby maintaining catalyst stability and reliability
Solution Approach 2:
The dissolved hydrogen acts as an intermediary that mediates between the hydrocarbon feed and catalyst surface. By being pre-dissolved in the liquid phase, hydrogen is uniformly distributed and readily available at the catalyst surface, preventing the formation of coke intermediates that would otherwise deposit and deactivate the catalyst
3Manufacturing precision
If conventional hydroprocessing methods are used, then diesel fuel can be produced, but cold flow properties are not improved and dewaxing requires separate equipment
Solution Approach 1:
The invention merges the dewaxing function with the hydroprocessing reaction by using the same liquid-full reactor system. The dissolved hydrogen enables simultaneous hydrodesulfurization, hydrodenitrogenation, and dewaxing in a single integrated process, eliminating separate dewaxing equipment and improving cold flow properties as part of the core manufacturing process
Solution Approach 2:
The liquid-full reactor system achieves multi-functionality by performing hydroprocessing and dewaxing operations simultaneously. The dissolved hydrogen provides universal reactivity that enables both sulfur/nitrogen removal and wax component modification, allowing a single device to accomplish multiple functions that would otherwise require separate equipment
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
The process achieves a high yield of middle distillate fuel with improved cold flow properties, such as reduced cloud point, cold filter plugging point, and pour point, while maintaining a high iso- to n-paraffin ratio, and significantly reduces the need for hydrogen recycling and expensive catalysts.
Implementation Method 1
dissolves hydrogen in a middle distillate fuel feedstock with a diluent, allowing for hydrotreating and dewaxing in a single phase
Implementation Method 2
using a zeolite catalyst that tolerates sulfur and nitrogen
Implementation Method 3
contacting the feedstock/diluent/hydrogen mixture with a hydrotreating catalyst in a first reaction zone, to produce a first product effluent; and contacting the first product effluent with a dewaxing catalyst in a second reaction zone
Data Source
AI summary
Novel liquid-full process for improving cold flow properties and increasing yield of middle distillate fuel feedstock by hydrotreating and dewaxing the feedstock in liquid-full reactors.