Dual Catalyst Hydroconversion for Jet Fuel Energy Density
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Solution Overview
Problem
Conventional hydrocracking processes for upgrading heavy hydrocarbon streams to jet and diesel products result in higher H2 consumption due to cracking, dealkylation, and unselective ring opening, leading to products with lower volumetric energy density and failing to meet specifications.
Innovation Solution
A process utilizing a single reactor with a dual or multiple catalyst system, combining hydrotreating, hydrofinishing, and hydroisomerization catalysts to upgrade heavy hydrocarbon feedstocks, where the heavy hydrocarbon feed is reacted with a hydrotreating catalyst followed by a hydrofinishing and/or hydroisomerization catalyst to produce high volumetric energy density jet and diesel products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional hydrocracking processes are used to upgrade heavy hydrocarbon streams, then jet and diesel products are produced, but H2 consumption increases due to cracking, dealkylation, and unselective ring opening
Solution Approach 1:
The catalyst system is segmented into multiple functional zones within a single reactor: a first catalyst bed for hydrotreating (removing heteroatoms) and a second catalyst bed for hydrofinishing (aromatic saturation). This segmentation allows each catalyst to perform its specific function efficiently, preventing unselective cracking reactions that would consume excessive hydrogen while maintaining high product yield.
Solution Approach 2:
Different catalyst compositions are placed in different locations within the reactor to create local functional zones. The first catalyst bed contains hydrotreating catalyst optimized for heteroatom removal, while the second bed contains hydrofinishing catalyst optimized for aromatic saturation. This local quality differentiation ensures that hydrogen is consumed only for necessary reactions, avoiding wasteful cracking while achieving the desired product quality.
2Quantity of substance
If conventional hydrocracking processes are used to upgrade heavy hydrocarbon streams, then jet and diesel products are produced, but volumetric energy density decreases and specifications are not met
Solution Approach 1:
The two-stage catalyst system segments the conversion process into heteroatom removal followed by aromatic saturation. This ensures that the final jet and diesel products have high aromatic content reduction (improving stability and energy density) while maintaining appropriate molecular weight distribution (preserving volumetric energy density and meeting specifications).
Solution Approach 2:
The process controls key parameters including aromatic saturation level, heteroatom removal extent, and product boiling range distribution through the sequential catalyst beds. By adjusting operating conditions (temperature, pressure, space velocity) and catalyst properties, the process optimizes volumetric energy density while ensuring products meet all specifications for jet and diesel fuels.
3Productivity
If multiple catalysts are used in separate reactors, then hydroconversion is achieved, but device complexity increases
Solution Approach 1:
The patent merges the hydrotreating and hydrofinishing catalyst beds into a single reactor vessel, creating a integrated dual-catalyst system. This consolidation maintains the hydroconversion efficiency of separate reactors while significantly reducing device complexity by eliminating the need for multiple reactors, interconnecting piping, and separate control systems. The catalysts are arranged in sequence within the same reactor, allowing continuous processing through a single unit.
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 effectively produces jet and diesel products with net heat of combustion exceeding 125,000 Btu/gal, meeting specifications, and improves low temperature properties such as freezing and cloud points, while reducing H2 consumption and catalyst deactivation.
Implementation Method 1
a catalyst composition comprising a metal component and a support, wherein the metal component comprises at least one of a Group VIII metal component and a Group VIB metal component, and the support comprises an inorganic oxide support
Implementation Method 2
a hydrocarbon feed is contacted with hydrogen to reduce its content of aromatic compounds
Data Source
AI summary
The present invention is directed to a process for converting heavy hydrocarbonaceous feeds to jet and diesel products: using a single reactor, dual catalyst system; or using a single reactor, multiple catalyst system.