Multi-Stage Hydrocarbon Conversion for Aromatic Yield
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Solution Overview
Problem
Current processes for producing aromatic hydrocarbons, such as benzene, face challenges including low yield, catalyst deactivation due to coking, and the need for complex and costly operations, particularly in converting light paraffinic hydrocarbons to aromatic hydrocarbons with reduced byproduct formation.
Innovation Solution
A hydrocarbon conversion process involving three stages, where a feed comprising non-aromatic hydrocarbons is processed with specific catalysts under controlled temperature and pressure conditions to enhance aromatic hydrocarbon yield and reduce catalyst coke formation, utilizing a first stage at lower temperatures and higher pressures, and a second stage at higher temperatures with a different catalyst to optimize aromatic hydrocarbon production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperature and low pressure conditions are used for aromatic hydrocarbon production, then aromatic hydrocarbon yield is improved, but catalyst deactivation due to coking increases
Solution Approach 1:
The process is divided into multiple reaction stages with different catalysts and conditions. The first stage uses a dehydrogenation catalyst at high temperature to produce aromatic hydrocarbons, while the second stage uses a different catalyst system to further process the product. This segmentation allows optimization of each stage independently, maintaining high yield while managing catalyst deactivation through staged processing rather than single-stage operation.
Solution Approach 2:
The invention changes the operating parameters by using high temperature (400-700°C) and high pressure (1-100 atm) conditions instead of conventional low pressure. This parameter change shifts the reaction equilibrium and kinetic favorability toward aromatic hydrocarbon production, improving yield while the high pressure suppresses catalyst coking by increasing the partial pressure of reactants and products.
2Productivity
If feed conversion is increased to improve aromatic hydrocarbon yield, then productivity is improved, but catalyst coking accumulation increases
Solution Approach 1:
The invention converts the harmful effect of high feed conversion (which causes coking) into a beneficial outcome by using high pressure conditions. The high pressure suppresses the formation of coke by shifting the reaction toward desired aromatic hydrocarbon products and by increasing the rate of hydrogen transfer reactions that prevent coke deposition. Thus, high feed conversion can be maintained without the usual harmful coking effects.
3Productivity
If conventional single-stage processes are used, then process simplicity is maintained, but aromatic hydrocarbon selectivity and yield are insufficient
Solution Approach 1:
The process uses multiple reaction stages with different catalyst systems. The first stage employs a dehydrogenation catalyst to convert paraffinic hydrocarbons to aromatic hydrocarbons, while the second stage uses a different catalyst to optimize the product distribution and reduce byproducts. This segmentation enables higher overall yield and selectivity by performing different functions in each stage, accepting the trade-off of increased process complexity for significantly improved productivity.
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 process increases the selectivity for aromatic hydrocarbons and decreases catalyst coke formation, allowing for longer operation cycles without regeneration, and reduces undesirable light hydrocarbon byproducts, improving overall efficiency and yield compared to conventional methods.
Implementation Method 1
contacting the feed with a first catalyst which comprises ≥10 wt. % of a first molecular sieve component and ≥0.005 wt. % of a first dehydrogenation component... contacting at least a portion of the raffinate with a second catalyst which comprises ≥10 wt. % of a second molecular sieve component and ≥0.005 wt. % of a second dehydrogenation component
Implementation Method 2
a first molecular sieve component and ≥0.005 wt. % of a first dehydrogenation component... a second molecular sieve component and ≥0.005 wt. % of a second dehydrogenation component
Data Source
AI summary
The invention relates to the hydrocarbon upgrading to produce aromatic hydrocarbon, to equipment and materials useful in such upgrading, and to the use of such upgrading for, e.g., producing aromatic hydrocarbon natural gas. The upgrading can be carried out in the presence of a dehydrocyclization catalyst comprising at least one dehydrogenation component and at least one molecular sieve.