Hydrotreatment Method with Indirect Heating for Renewable Feedstocks
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Solution Overview
Problem
The integration of renewable sources like vegetable oils and animal fats into traditional refining processes for fuel production faces challenges due to their high molecular weight and viscosity, leading to compatibility issues with modern engines and the need for precise temperature control in hydrotreatment processes to prevent undesirable reactions such as polymerization and catalyst coking.
Innovation Solution
A hydrotreatment method involving a liquid recycle at the entrance to each catalytic zone, allowing for precise temperature control and indirect heating, which enables efficient hydrogenation, deoxygenation, and hydrodenitrogenation of feeds to produce high-quality n-paraffins suitable for gas oil and kerosene production, meeting specific fuel standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If feeds from renewable sources (vegetable oils, animal fats) are directly used in gas oils, then the demand for renewable fuels is met, but engine compatibility problems occur (clogging of injectors, uncontrolled combustion, toxic emissions)
Solution Approach 1:
The patent applies parameter changes by modifying the chemical structure of triglycerides through hydrotreatment reactions. The process changes molecular weight, viscosity, and chemical composition parameters to convert renewable feeds into engine-compatible fuels meeting EN590 and ASTM D1655 specifications
Solution Approach 2:
The patent extracts harmful components from renewable feeds through hydrotreatment. Oxygen is removed via deoxygenation reactions (hydrodeoxygenation, decarboxylation, decarbonylation), and nitrogen is removed via hydrodenitrogenation, eliminating substances that cause engine problems while retaining the desirable hydrocarbon chains
2Productivity
If temperature is increased to achieve hydrodenitrogenation, then nitrogen removal is improved, but runaway reactions and catalyst coking occur due to exothermic nature
Solution Approach 1:
The patent segments the hydrotreatment process into multiple catalytic zones with different functions. The first zone operates at lower temperature (200-260°C) for hydrogenation and deoxygenation, while subsequent zones operate at higher temperatures (260-320°C) for hydrodenitrogenation. This segmentation allows temperature control to prevent runaway reactions while achieving complete nitrogen removal
Solution Approach 2:
The patent uses recycled hydrotreated liquid effluent as an intermediary cooling medium. The recycled liquid, drawn from after the separation stage, is mixed with fresh feed upstream of each catalytic zone to absorb excess heat and control reaction temperatures, preventing catalyst coking and runaway reactions
3Temperature
If liquid recycle rate is increased to control exothermic reactions, then temperature control is improved, but equipment costs and hydraulic capacity requirements increase
Solution Approach 1:
The patent applies local quality by providing targeted cooling at specific locations upstream of each catalytic zone using the recycled liquid. This localized temperature control is more efficient than uniform cooling throughout the system, reducing overall hydraulic capacity requirements while maintaining precise temperature control where needed
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 method effectively controls exothermic reactions, reduces equipment costs, and produces fuels with improved cetane characteristics and low-temperature properties, ensuring compatibility with modern engines and compliance with industry standards.
Implementation Method 1
indirect heating of the effluent from the first catalytic zone and adjustment of the temperature at the entrance to the following catalytic zones
Implementation Method 2
hydrogenation of unsaturations
Implementation Method 3
hydrodeoxygenation: elimination of oxygen by consumption of hydrogen and leading to formation of water
Implementation Method 4
decarboxylation/decarbonylation: elimination of oxygen by formation of carbon monoxide and dioxide: CO and CO2
Implementation Method 5
hydrodenitrogenation: elimination of nitrogen by formation of NH3
Implementation Method 6
complex reactions which are favoured by a hydrogenating catalytic system
Implementation Method 7
The hydrogenation of unsaturations (carbon-carbon double bonds) is strongly exothermic and the increase in temperature resulting from the release of heat of the saturation reactions
Data Source
AI summary
The invention describes a method of treating feeds from renewable sources comprising:a hydrotreatment stage a) comprising at least two catalytic zones in which the entry stream comprising said feed mixed with at least a part of a hydrotreated liquid effluent from stage b) is introduced into the first catalytic zone at a temperature comprised between 150 and 260° C., and the effluent from the first catalytic zone is then introduced, mixed with at least a part of a hydrotreated liquid effluent from stage b) and preheated, into the following catalytic zone or zones at a temperature comprised between 260 and 320° C.,a stage b) of separation of the effluent from the hydrotreatment stage a) permitting the separation of a gaseous effluent and of a hydrotreated liquid effluent of which at least a part is recycled upstream from each catalytic zone of stage a).