Single-Stage Hydroprocessing of Paraffinic Feedstocks for Jet Fuel
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing processes for producing sustainable aviation fuel and diesel from paraffins derived from sustainable feedstocks face challenges in meeting fuel specifications such as freeze point, cloud point, and pour point, and producing high-quality base oil due to the high carbon numbers of the paraffins produced, which require additional hydrocracking and hydroisomerization stages.
Innovation Solution
A single reaction stage is used for hydrocracking and hydroisomerizing the feed stream, combining both processes to reduce capital costs and improve cold flow properties, while producing jet fuel and base oil suitable for lubricants, by adjusting hydroisomerization severity to meet fuel specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate hydrocracking and hydroisomerization units are used to process paraffins, then fuel specifications (freeze point, cloud point, pour point) can be met, but device complexity and capital costs increase
Solution Approach 1:
The patent combines hydrocracking and hydroisomerization into a single integrated reaction unit with a dual-function catalyst system. The catalyst contains both hydrocracking components (acid sites for C-C bond cleavage) and hydroisomerization components (metal sites for skeletal isomerization), allowing both processes to occur simultaneously in one reactor. This eliminates the need for separate hydrocracking and hydroisomerization units while meeting fuel specification requirements for freeze point, cloud point, and pour point.
2Productivity
If higher carbon number paraffins are produced from sustainable feedstocks, then renewable fuel production increases, but cold flow properties deteriorate
Solution Approach 1:
The patent employs a dual-function catalyst system that simultaneously performs hydrocracking to reduce carbon numbers and hydroisomerization to improve cold flow properties. The catalyst comprises metal sites (Group VIII metals like Pt, Pd, or Ru) for hydrogenation and skeletal isomerization, combined with acid sites (from zeolites or amorphous silica-alumina) for hydrocracking. By adjusting the ratio and strength of these catalytic functions, the process optimizes the balance between producing sufficient fuel yield from high-carbon sustainable feedstocks and achieving acceptable cold flow properties through controlled carbon number reduction and branching.
3Productivity
If hydrocracking severity is increased to reduce carbon numbers, then jet fuel yield increases, but isomer content and cold flow properties may be compromised
Solution Approach 1:
The patent uses a composite catalyst system that integrates both hydrocracking and hydroisomerization functionalities in a single catalyst formulation. The composite catalyst typically combines metal particles (0.1-5 wt% Pt, Pd, or Ru) supported on an acidic matrix (zeolite or amorphous silica-alumina with controlled acidity). This composite structure enables synergistic interaction where the metal sites promote isomerization and the acid sites promote cracking, allowing the process to achieve high jet fuel yield through controlled carbon number reduction while simultaneously improving cold flow properties through skeletal branching. The dual functionality ensures that even at high conversion levels, sufficient isomer content is maintained to meet cold flow specification.
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 fuel and base oil that meets specifications, increasing jet fuel yield and reducing the carbon footprint, while eliminating the need for separate hydroisomerization units, thus enhancing profitability through Renewable Identification Numbers (RINs) and government incentives.
Implementation Method 1
hydrocracking a hydrocracking feed stream comprising greater than 90% paraffins in a hydrocracking reactor in the presence of hydrogen over a hydrocracking catalyst
Implementation Method 2
hydroisomerizing the hydrocracked stream in an hydroisomerization reactor in the presence of hydrogen over a hydroisomerization catalyst selected from
Data Source
AI summary
A process for hydroprocessing a sustainable feedstock is disclosed. The process comprises hydrocracking a hydrocracking feed stream comprising greater than 90% paraffins in a hydrocracking reactor in the presence of hydrogen over a hydrocracking catalyst comprising one or more Group VIII metal and/or Group VIB to provide a hydrocracked stream. The hydrocracking reactor is operated at a temperature of about 290° C. (550° F.) to about 450° C. (842° F.) and a pressure of about 2.7 MPa (gauge) (400 psig) to about 20.7 MPa (gauge) (3000 psig). The hydrocracked stream is hydroisomerized in a hydroisomerization reactor in the presence of hydrogen over a hydroisomerization catalyst to provide a hydroisomerized stream. The hydroisomerized stream is separated to provide a jet fuel stream, a diesel stream, and an unconverted oil stream.