Hydrotreating Vegetable Oils Using Segmented Reaction Zones
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Solution Overview
Problem
Existing hydrotreating processes for vegetable oils and animal fats require high hydrogen amounts, lead to heat release issues, and result in undesirable side reactions like cracking and fouling, making them inefficient and prone to catalyst deactivation.
Innovation Solution
A process involving two hydrotreatment reaction zones where an oxygenate feed stream comprising methyl or ethyl esters of carboxylic acids is contacted with a hydrocarbon stream under specific conditions to convert esters to hydrocarbons, with the option to further process the product in a second zone for enhanced conversion, using catalysts like NiMo and CoMo to manage heat and catalyst activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional hydrotreating processes are used to convert vegetable oils and animal fats, then conversion to hydrocarbons is achieved, but high hydrogen consumption and heat release issues occur
Solution Approach 1:
The hydrotreating process is divided into two distinct reaction zones with different catalyst types. The first zone uses NiMo catalyst for initial hydrodeoxygenation, while the second zone uses CoMo catalyst for further conversion. This segmentation allows optimized conditions in each zone, reducing overall hydrogen consumption and managing heat release through staged processing.
Solution Approach 2:
The process changes catalyst parameters between the two reaction zones, switching from NiMo to CoMo catalyst. This parameter change enables different reaction conditions in each zone, optimizing hydrogen utilization and heat management while achieving complete conversion of esters to hydrocarbons.
2Productivity
If conventional hydrotreating processes are used, then ester conversion is achieved, but undesirable side reactions like cracking and fouling occur
Solution Approach 1:
The process segments the conversion process into two stages with different catalysts. The first NiMo zone performs initial hydrodeoxygenation with controlled conditions, while the second CoMo zone completes the conversion. This segmentation prevents excessive heat release and unwanted side reactions that would occur in a single-stage process.
Solution Approach 2:
The process converts the potentially harmful heat release of hydrotreating into a beneficial feature by using the exothermic reaction heat to maintain optimal reaction temperatures in the second zone, while the staged approach prevents runaway reactions and catalyst deactivation.
3Productivity
If conventional hydrotreating processes are used, then conversion is achieved, but catalyst deactivation occurs
Solution Approach 1:
The process divides the conversion function between two catalysts with different characteristics. NiMo catalyst handles the initial conversion, while CoMo catalyst completes the process. This segmentation reduces the operational stress on each catalyst, extending their operational life and reducing deactivation rates.
Solution Approach 2:
The process changes catalyst parameters between zones, using NiMo in the first zone and CoMo in the second. This parameter change allows optimized reaction conditions for each catalyst type, preventing conditions that would cause rapid deactivation and extending overall catalyst life.
4Ease of manufacture
If transesterification is used to convert vegetable oils, then FAME production is achieved, but poor cold flow and lower stability result
Solution Approach 1:
The process replaces the chemical transesterification method with a hydrotreating process that converts esters directly to hydrocarbons through hydrogenation. This substitution eliminates the ester moieties that cause poor cold flow and stability issues, producing stable hydrocarbon fuels while maintaining ease of manufacture through existing refinery infrastructure.
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 reduces hydrogen consumption, minimizes heat-related issues, and extends catalyst life, producing hydrocarbon fuels with low sulfur content and improved stability, suitable for use as diesel, heating, or jet fuel, while being compatible with existing refinery infrastructure.
Implementation Method 1
These methods remove undesirable oxygen by hydrodeoxygenation to produce water, hydrodecarbonylation to produce CO, or hydrodecarboxylation to produce CO2.
Implementation Method 2
In hydrodeoxygenation, unsaturated carbon-carbon bonds present in feed molecules are saturated (hydrogenated) before deoxygenation.
Implementation Method 3
using catalysts like NiMo and CoMo to manage heat and catalyst activity
Implementation Method 4
Direct hydrotreating of vegetable oils or animal fats requires a relatively high amount of hydrogen and is generally accompanied by a large amount of heat release
Data Source
AI summary
A process for preparing fuels, such as diesel fuels or jet fuels, by hydrotreating vegetable oils or fatty acid derivatives that may be applied to existing equipment for treating fossil fuels. The process comprises feeding hydrotreating a combined oxygenate feed stream, such as FAME, and a hydrocarbon feed stream until not more than 86 wt % of the esters in the oxygenate feed stream are converted to hydrocarbons, and optionally further hydrotreating the product stream within at least a second hydrotreatment reaction zone until at least 90 wt % of the esters in the oxygenate feed stream are converted to hydrocarbons, before removing and separating a hydrocarbon stream suitable for use as fuel.