Renewable Fuel Pre-Hydrogenation for Hydrogen Purity Reduction
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Solution Overview
Problem
Current processes for producing hydrocarbons from renewable feedstocks, such as plant and animal fats, require high purity and high pressure hydrogen, leading to increased costs and inefficiencies, and result in reduced shelf life and increased capital and operating expenses due to contamination and oxidation issues.
Innovation Solution
A process involving partial hydrogenation of the feedstocks before deoxygenation and isomerization, using lower purity and pressure hydrogen in the pre-hydrogenation stage, which reduces hydrogen demand and extends the shelf life of the feedstocks, allowing for more efficient storage and processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high purity and high pressure hydrogen is used in the deoxygenation zone, then the deoxygenation efficiency is improved, but the hydrogen cost and processing complexity increase
Solution Approach 1:
The hydrogenation process is divided into two distinct zones: a pre-hydrogenation zone using low purity/low pressure hydrogen to handle bulk hydrogenation, and a deoxygenation zone using high purity/high pressure hydrogen for precise deoxygenation. This segmentation allows each zone to use appropriately matched hydrogen quality, reducing overall processing complexity while maintaining deoxygenation efficiency.
Solution Approach 2:
The pre-hydrogenation zone performs preliminary hydrogenation of the feedstock before it enters the deoxygenation zone. By partially hydrogenating the feedstock first, the subsequent deoxygenation step becomes more efficient and requires less high purity hydrogen, thereby reducing the complexity of hydrogen supply requirements while maintaining deoxygenation performance.
2Reliability
If pretreatment steps are added to remove contaminants, then catalyst protection is improved, but feedstock loss and operating cost increase
Solution Approach 1:
Instead of complete removal of all contaminants through extensive pretreatment, the process applies partial pretreatment only where necessary to protect downstream catalysts. The pre-hydrogenation zone handles the bulk of impurity management, allowing minimal pretreatment that removes only the most harmful contaminants, thereby reducing feedstock loss while still protecting catalysts.
3Adaptability or versatility
If polyunsaturated lipids are present in feedstock, then feedstock diversity is improved, but oxidation stability and shelf life deteriorate
Solution Approach 1:
The pre-hydrogenation zone performs preliminary saturation of unsaturated bonds in polyunsaturated lipids before the feedstock enters subsequent processing zones. This preliminary action converts unstable polyunsaturated bonds into more stable saturated bonds, extending shelf life and improving oxidation stability while still allowing acceptance of diverse feedstock types with varying degrees of unsaturation.
Solution Approach 2:
The process changes the chemical parameters of the feedstock by partially hydrogenating polyunsaturated lipids in the pre-hydrogenation zone. This parameter change (reducing unsaturation) improves oxidation stability and shelf life while maintaining the ability to process diverse feedstock types, as the hydrogenation程度 can be adjusted based on the specific feedstock composition.
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 decreases the need for high purity/high pressure hydrogen, reduces contamination-related costs, and enhances the stability and storage capabilities of the feedstocks, leading to more efficient and cost-effective production of hydrocarbon fuels.
Implementation Method 1
pre-hydrogenating the pretreated feedstock in a pre-hydrogenation zone, the pre-hydrogenation zone comprising at least one reactor having a hydrogenation catalyst and being operated under conditions to partially hydrogenate the pretreated feedstock
Implementation Method 2
deoxygenating the pre-hydrogenated feedstock in a deoxygenation zone, the deoxygenation zone comprising at least one reactor having a catalyst capable of deoxygenating the pre-hydrogenated feedstock
Implementation Method 3
deoxygenating (via catalytic decarboxylation, decarbonylation and/or hydrodeoxygenation)
Implementation Method 4
deoxygenating (via catalytic decarboxylation, decarbonylation and/or hydrodeoxygenation)
Data Source
AI summary
Processes for the production of hydrocarbons from a renewable feedstock in which the renewable feedstock is partially hydrogenated prior to being deoxygenated. The partially hydrogenation utilizes a lower pressure, lower purity or both hydrogen gas compared to the deoxygenation. The partially hydrogenated product may be stored in containers and transported to be deoxygenated. Prior to partially hydrogenation, the feedstock may be pretreated. After deoxygenation an isomerization zone may be used to increase the cold flow properties for a diesel fuel.