Hydroisomerization Reactor Recycle Stream for Jet Fuel Freeze Point
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The production of jet fuel from biorenewable feedstocks faces challenges in meeting jet fuel specifications, particularly the freeze point, due to carryover of C16 hydrocarbons, which results in yield loss and poor cold flow properties.
Innovation Solution
The process involves hydrotreating a biorenewable feed stream to remove heteroatoms and hydroisomerizing it to improve cold flow properties. Specifically, the process separates a hydrotreated hot separator vapor stream into a liquid stream that is routed to the hydroisomerization reactor, ensuring that normal C16 hydrocarbons are hydroisomerized to address carryover issues without compromising yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If hydroisomerization reactor is operated at higher severity to meet jet fuel freeze point specification, then freeze point is improved, but jet fuel yield is reduced by about 1 wt% to about 1.5 wt%
Solution Approach 1:
The process segments the hydrocarbon stream by separating C16 hydrocarbons from the jet fuel product stream through distillation. This segmentation allows the C16 fraction to be diverted to hydroisomerization while the remaining stream meets freeze point specifications without requiring severe hydroisomerization conditions that would reduce yield.
Solution Approach 2:
The harmful C16 hydrocarbon fraction is extracted from the jet fuel stream through distillation separation. By removing this fraction that causes poor cold flow properties, the remaining jet fuel naturally meets freeze point specifications without subjecting the entire stream to severe hydroisomerization that would compromise yield.
2Manufacturing precision
If hydrocracking is performed to meet jet fuel specifications for larger molecules, then molecular weight distribution is improved, but production yield is reduced
Solution Approach 1:
Larger C16 hydrocarbon molecules are extracted from the feed stream through distillation before entering the hydroisomerization reactor. This pre-separation prevents these molecules from requiring severe hydrocracking to meet specifications, thereby reducing unnecessary yield loss while still achieving the required molecular weight distribution in the final jet fuel product.
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
This approach allows for the production of jet fuel range material that meets the jet fuel specification without affecting yield, thereby improving the cold flow properties and reducing the freeze point of the jet fuel.
Implementation Method 1
hydrotreating a biorenewable feed stream to remove heteroatoms
Implementation Method 2
Hydrotreating is a process in which hydrogen is contacted with hydrocarbons in the presence of hydrotreating catalysts
Implementation Method 3
hydroisomerizing it to improve cold flow properties
Implementation Method 4
Hydroisomerization or hydrodewaxing is a hydroprocessing process that increases the alkyl branching on a hydrocarbon backbone in the presence of hydrogen and hydroisomerization catalyst
Implementation Method 5
Hydrocracking is a hydroprocessing process in which hydrocarbons crack in the presence of hydrogen and hydrocracking catalyst to lower molecular weight hydrocarbons
Data Source
AI summary
A process and apparatus for producing biofuel from biorenewable feedstock is disclosed. The process comprises hydrotreating the biorenewable feed stream in a hydrotreating reactor to hydrodeoxygenate a biorenewable feed stream to provide a hydrotreated effluent stream. The hydrotreated effluent stream is separated in a hot separator into a hot separated vapor stream and a hot separated liquid stream. A hydroisomerization feed stream is taken from the hot separated liquid stream and hydroisomerized in a hydroisomerization reactor to provide a hydroisomerized stream. All or a portion of a return stream taken from the hot separated vapor stream is recycled to the hydroisomerization reactor. The disclosed process and apparatus minimize the carryover of the normal C16 to the biofuel and maximizes the hydroisomerization of n-paraffin hydrocarbons in the hydrotreated effluent stream to produce a biofuel which meets the biofuel specification without affecting or compromising the biofuel yield.