Two-Stage Hydrogenation of Aromatic Feedstocks
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Solution Overview
Problem
Current processes for hydrogenating aromatic compounds in hydrocarbon feedstocks struggle to achieve low enough concentrations of aromatic compounds, particularly benzene, to comply with stringent specifications such as less than 20 ppm by weight, while being simple to implement and cost-effective.
Innovation Solution
A two-stage hydrogenation process using a reactor with a nickel or platinum catalyst dispersed on a substrate, where the first stage reduces aromatic compound content to less than 1,000 ppm and the second stage further reduces it to less than 20 ppm by weight, with specific temperature, pressure, and flow rate conditions optimized for each stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single-stage hydrogenation process is used, then the process is simple to implement, but the aromatic compound content cannot be reduced to below 20 ppm by weight
Solution Approach 1:
The hydrogenation process is divided into two distinct stages: a first stage that reduces aromatic compounds to below 1,000 ppm, and a second stage that further reduces them to below 20 ppm. This segmentation allows each stage to be optimized independently for its specific reduction target, achieving high precision in aromatic compound removal while maintaining manageable process complexity through modular design.
2Productivity
If hydrogenation is carried out at higher temperatures to improve reaction rate, then productivity increases, but the selectivity and control over aromatic compound removal decreases
Solution Approach 1:
The process uses two stages with different temperature conditions: the first stage operates at higher temperatures (200-400°C) to achieve rapid hydrogenation and high productivity, while the second stage uses lower temperatures (100-300°C) to provide selective removal of remaining aromatic compounds. This temporal segmentation of temperature conditions allows both high productivity and precise control to be achieved.
Solution Approach 2:
The process dynamically adjusts temperature conditions between the two stages based on the specific requirements of each hydrogenation phase. The first stage employs elevated temperatures to maximize reaction rate and productivity, while the second stage transitions to lower temperatures to enhance selectivity and control over the removal of trace aromatic compounds, thereby optimizing both productivity and precision throughout the process.
3Manufacturing precision
If a two-stage hydrogenation process is used to achieve below 20 ppm aromatic compounds, then manufacturing precision improves, but the process complexity and cost increase
Solution Approach 1:
The hydrogenation process is segmented into two distinct stages with different operational parameters and catalyst configurations. The first stage handles bulk aromatic compound removal under more aggressive conditions, while the second stage focuses on trace aromatic elimination. This segmentation enables high manufacturing precision for aromatic compound content while maintaining ease of manufacture through standardized, modular process units that can be implemented using conventional hydrogenation technology.
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 effectively achieves aromatic compound concentrations below 20 ppm by weight, meeting stringent specifications, and can be applied to various hydrocarbon feedstocks, including those with high initial aromatic content, ensuring compliance with environmental and industrial standards.
Implementation Method 1
a hydrogenation catalyst comprising nickel or platinum dispersed on a substrate
Implementation Method 2
Process for hydrogenation of aromatic compounds contained in a feedstock comprising hydrocarbons
Data Source
AI summary
Process for hydrogenation of aromatic compounds in a feedstock comprising hydrocarbons having at least five carbon atoms, comprising:a) contacting feedstock, a hydrogen gas, and a nickel or platinum hydrogenation catalyst at 100 to 400° C., 0.5 to 8 MPa, and a feedstock flow rate 0.5 to 5 h−1, as to produce a partially-hydrogenated hydrocarbon feedstock and gas; andb) contacting the partially-hydrogenated feedstock, and a nickel or platinum hydrogenation catalyst at 100 and 400° C., a pressure of between 0.5 and 8 MPa, with a flow rate of the partially-hydrogenated feedstock between 0.3 and 8 h−1, a ratio between the volume of hydrogen and the volume of the partially-hydrogenated feedstock between 0.3 and 3 Nm3/m3, and a ratio between the superficial mass flow rate of the partially-hydrogenated feedstock and the superficial mass flow rate of gas (Ul/Ug) at the inlet of the reactor between 50 and 500.