Renewable Jet Fuel Fractionation to Limit Sour Hydrocracking
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Solution Overview
Problem
Conventional methods for producing renewable jet fuel involve multi-stage processes that increase complexity and cost, and single-stage processes often result in reduced selectivity and yield due to 'sour' conditions, leading to overcracking and loss of jet boiling range fractions.
Innovation Solution
A single-stage process is implemented using a sweet hydrocracking stage followed by separation to form a jet boiling range fraction, with either non-hydrocracked or dewaxed components, or dewaxing under sour conditions without hydrocracking, allowing for noble metal catalyst use and improved yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-stage process is used for renewable jet production, then process complexity and cost are reduced, but selectivity and yield are reduced due to overcracking under sour conditions
Solution Approach 1:
The process segments the treatment of different carbon chain ranges by separating the feedstock into C10-C16 and C17+ portions, applying different processing strategies to each segment to optimize both yield and product quality
Solution Approach 2:
The process changes operating parameters by conducting hydrocracking at lower severity conditions (300-400°C, 50-150 bar) compared to conventional processes, and uses sweet conditions rather than sour conditions to prevent overcracking and improve selectivity
2Productivity
If exposure to hydrocracking conditions is minimized, then yield of renewable jet fuel is enhanced, but cold flow properties may be compromised
Solution Approach 1:
The process performs preliminary dewaxing on the C17+ fraction before hydrocracking, which prepares the feedstock for more efficient hydrocracking and helps ensure cold flow properties are achieved with minimal hydrocracking exposure
Solution Approach 2:
The process applies different quality treatments to different portions of the feedstock, with the C10-C16 fraction receiving dewaxing treatment and the C17+ fraction receiving both dewaxing and hydrocracking treatment, optimizing both yield and cold flow properties
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 reduces complexity and cost by minimizing exposure to hydrocracking conditions while maintaining target cold flow properties, enhancing the yield of renewable jet fuel with low freeze points.
Implementation Method 1
triglycerides, FAME, FFA are hydrotreated with conventional hydrotreating catalysts under typical hydrotreating conditions to convert fatty acid chains to n-paraffins
Implementation Method 2
contacting at least a portion of the second fraction with a hydrocracking catalyst under hydrocracking conditions to produce a hydrocracked effluent
Implementation Method 3
cascading at least a portion of the hydrocracked effluent into a reactor containing a dewaxing catalyst under dewaxing conditions to produce an effluent comprising the hydrocracked, dewaxed co-feed
Implementation Method 4
The deoxygenated liquid fraction is separated to form at least i) a jet boiling range fraction having a T90 distillation point of 230° C. or lower and a freeze point of −40° C. or lower
Data Source
AI summary
Systems and methods are provided for production of renewable jet fuel and/or jet fuel blending component fractions using a single stage reaction system. Although only a single separation stage is used, the systems and methods can reduce or minimize the volume of feedstock that is exposed to hydrocracking conditions while still producing a jet boiling range fraction having beneficial cold flow properties.