Paraffinic Feedstock Hydroprocessing for Jet Fuel Cold Flow
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Solution Overview
Problem
Existing processes for producing sustainable aviation fuel and diesel from biorenewable feedstocks face challenges in meeting fuel specifications such as freeze point, cloud point, and pour point due to the production of paraffins with higher carbon numbers, and there is a need for efficient methods to produce high-quality jet fuel and lubricant oil from sustainable feedstocks.
Innovation Solution
A single reaction stage process combining hydrocracking and hydroisomerization is used to convert paraffins into sustainable distillates, decoupling the effect of hydrocracking carbon number reduction to improve cold flow properties, and produce jet fuel and base oil suitable as lubricant components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrocracking is used to reduce carbon numbers of paraffins, then jet fuel yield is improved, but cold flow properties deteriorate due to loss of isomer content
Solution Approach 1:
The patent combines hydrocracking and hydroisomerization into a single integrated reaction stage using a bifunctional catalyst. This merging allows simultaneous carbon number reduction and isomer formation, resolving the contradiction by achieving both high jet fuel yield and improved cold flow properties in one process rather than sequential steps that would compromise one property for the other.
Solution Approach 2:
The patent changes the operational parameters by using a bifunctional catalyst with specific metal components (Group VIII, VIB, or VB metals) on acidic supports (zeolites, amorphous silica-alumina, or aluminophosphates). This catalyst system enables operation at temperatures of 290-450°C and pressures of 2.7-20.7 MPa to simultaneously achieve hydrocracking and hydroisomerization, transforming the product distribution to meet both yield and cold flow specifications.
2Manufacturing precision
If multiple reaction stages are used for hydrocracking and hydroisomerization, then product quality is improved, but capital and operating costs increase
Solution Approach 1:
The patent consolidates multiple reaction stages (hydrocracking and hydroisomerization) into a single reaction stage with a bifunctional catalyst. This merging reduces the number of reactors, separators, and associated equipment needed, thereby lowering capital costs and simplifying operation while maintaining product quality through the synergistic action of the combined catalyst functions.
Solution Approach 2:
The bifunctional catalyst performs multiple functions simultaneously: it provides metal sites for hydrogenation/dehydrogenation and acidic sites for cracking and isomerization. This multi-functionality in a single catalyst system eliminates the need for separate catalyst beds and reaction stages, reducing both capital investment and operating complexity while achieving the desired product specifications.
3Manufacturing precision
If hydrocracking severity is increased to meet fuel specifications, then carbon number reduction is improved, but isomer content decreases
Solution Approach 1:
The patent changes the chemical environment by introducing a bifunctional catalyst with both metal and acidic sites. This allows the system to operate at hydrocracking severities that reduce carbon numbers to meet fuel specifications while the acidic sites simultaneously promote isomerization, maintaining isomer content in the product. The dual-function catalyst creates a new operational parameter space where both objectives can be achieved together.
Solution Approach 2:
The bifunctional catalyst is a composite material combining metal components (Group VIII, VIB, or VB) with acidic supports (zeolites, amorphous silica-alumina, or aluminophosphates). This composite structure provides both hydrogenation capability and cracking/isomerization activity, enabling simultaneous carbon number reduction and isomer formation that neither component could achieve alone.
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 meets jet fuel specifications and produces high-quality base oil by reducing capital and operating costs through a single reaction stage, enhancing jet fuel yield and cold flow properties while utilizing sustainable feedstocks.
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
Implementation Method 3
Hydrotreating is a process in which hydrogen is contacted with hydrocarbons in the presence of hydrotreating catalysts which are primarily active for the removal of heteroatoms, such as sulfur, nitrogen, oxygen and metals from the hydrocarbon feedstock
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.