Single Catalyst Cycled Through Reformers for Aromatics
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Solution Overview
Problem
Current methods for upgrading naphtha feedstreams to increase aromatic content, such as benzene, toluene, and xylenes, are limited by the need for multiple catalysts and high costs, and do not effectively optimize reaction conditions for maximizing yields of aromatics in the C6 to C8 range.
Innovation Solution
A process that uses a single catalyst cycled through reactors and regenerators, with separate reaction conditions for light and heavy hydrocarbon streams, optimizing temperature profiles and residence times to enhance the production of aromatics by segregating naphtha feedstreams and processing them in non-isothermal and isothermal zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple catalysts are used for different hydrocarbon streams, then the aromatic production is optimized, but the device complexity and cost increase
Solution Approach 1:
A single catalyst system is designed to perform multiple functions by processing both light (C6) and heavy (C7-C8) hydrocarbon streams. The catalyst is cycled through multiple reformers handling different feedstocks, eliminating the need for separate catalyst systems while maintaining optimized aromatic production for each stream type.
Solution Approach 2:
The patent combines the functionality of multiple catalyst systems into a single catalyst that serves all reformers. The catalyst is shared across different reaction zones processing light and heavy naphtha, merging what would traditionally require separate catalyst systems into one universal catalyst solution.
2Device complexity
If a single catalyst is used across all reformers, then the device complexity is reduced, but the ability to optimize reaction conditions for different hydrocarbon streams is limited
Solution Approach 1:
The catalyst system is made dynamic by cycling it through different reformers with different feedstocks (light and heavy naphtha). The catalyst adapts to different reaction conditions in each reformer, with temperature and residence time adjusted according to the specific hydrocarbon stream being processed, allowing a single catalyst to serve multiple functions.
Solution Approach 2:
Different reaction parameters (temperature, residence time) are applied to the same catalyst when it processes different hydrocarbon streams. Light naphtha is processed at higher temperatures with shorter contact times, while heavy naphtha is processed at lower temperatures with longer contact times, allowing the single catalyst to be optimized for each stream type.
3Quantity of substance
If light naphtha is processed at high temperature with long contact time, then conversion is improved, but selectivity to aromatics decreases due to over-cracking
Solution Approach 1:
The patent optimizes the balance between temperature and contact time for light naphtha processing. By adjusting these parameters within specific ranges, the process achieves high conversion while maintaining aromatic selectivity, preventing over-cracking that would occur with excessively long contact times or temperatures.
4Manufacturing precision
If heavy naphtha is processed at low temperature with short contact time, then aromatic selectivity is improved, but conversion is insufficient
Solution Approach 1:
The patent optimizes the balance between temperature and contact time for heavy naphtha processing. By adjusting these parameters within specific ranges, the process achieves high aromatic selectivity while maintaining sufficient conversion, avoiding the need for excessively high temperatures that would compromise selectivity.
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 increases the yields of aromatics by allowing for different operating conditions with a single catalyst, reducing costs and improving the efficiency of aromatic production in the C6 to C8 range, counterintuitively requiring shorter contact times for C6 compounds and higher temperatures.
Implementation Method 1
The catalyst is passed from a regenerator to a first reformer, and generates a catalyst effluent stream. The catalyst effluent stream from the first reformer is passed to a second reformer
Implementation Method 2
The reaction conditions in the reformers include the first reformer reaction temperature greater than the second reformer reaction temperature
Data Source
AI summary
A process for reforming a hydrocarbon stream is presented. The process involves splitting a naphtha feedstream to at least two feedstreams and passing each feedstream to separation reformers. The reformers are operated under different conditions to utilize the differences in the reaction properties of the different hydrocarbon components. The process utilizes a common catalyst, and common downstream processes for recovering the desired aromatic compounds generated.