Biomass Aromatics Process via Segmented Catalyst Stages
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Solution Overview
Problem
Current processes for producing aromatics from biomass have low carbon availability and yield, and result in a low proportion of xylene in the aromatic product, leading to increased operation costs and complexity in separation and purification steps.
Innovation Solution
A process involving a specific sequence of reaction steps using a compound with a lactone group as a platform compound, including decarboxylation, dimerization, and aromatization reactions with layered catalysts, to enhance carbon availability, yield, and selectivity to xylene, resulting in a product rich in xylene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional processes are used to convert biomass to aromatics, then the process can produce aromatic products, but the carbon availability and yield are relatively low
Solution Approach 1:
The patent segments the conversion process into three distinct reaction stages: (1) decarboxylation of platform compounds to form intermediates, (2) oligomerization of intermediates to form C8+ hydrocarbons, and (3) cyclization and aromatization to form final aromatic products. Each stage uses optimized catalysts and conditions to maximize carbon utilization at that step, thereby improving overall carbon availability and aromatic yield from biomass.
Solution Approach 2:
The patent systematically optimizes reaction parameters including temperature (50-250°C for decarboxylation, 200-400°C for oligomerization, 300-500°C for aromatization), pressure (1-10 MPa), catalyst composition (zeolite types, metal promoters), and space velocity to maximize carbon conversion efficiency. These parameter changes enable higher aromatic yields while minimizing carbon loss to gases or coke.
2Quantity of substance
If conventional processes are used to produce aromatics from biomass, then aromatic products can be obtained, but the proportion of xylene is low
Solution Approach 1:
The patent employs different catalysts with specific pore structures and acid site distributions tailored for each reaction stage. The oligomerization catalyst (e.g., ZSM-22, ZSM-23) has pore structures that favor C8 hydrocarbon formation, while the aromatization catalyst (e.g., ZSM-5, ZSM-11) has shape-selective properties that preferentially produce xylene isomers. This local optimization of catalyst properties at each stage maximizes xylene selectivity without sacrificing overall aromatic yield.
Solution Approach 2:
The patent uses composite catalyst systems combining multiple functional components: decarboxylation catalysts (e.g., sulfonated carbon, heteropolyacids), oligomerization catalysts (e.g., ZSM-22, ZSM-23 with specific Si/Al ratios), and aromatization catalysts (e.g., ZSM-5, ZSM-11 with metal promoters). These composite material systems work synergistically to achieve high xylene proportion while maintaining high aromatic productivity through optimized carbon flow through each reaction stage.
3Ease of manufacture
If conventional processes are used, then aromatics can be produced, but operation cost and complexity of separation and purification steps are increased
Solution Approach 1:
The patent performs preliminary shape-selective synthesis in the reaction stage itself, where the catalyst pore structures pre-organize the product distribution to favor xylene isomers. This preliminary action reduces the complexity of downstream separation by eliminating the need for complex fractional distillation sequences, thereby reducing operation costs while maintaining high aromatic productivity.
4Loss of substance
If existing processes are used to convert biomass to aromatics, then the process can proceed, but carbon is lost as gaseous carbon and carbon deposition
Solution Approach 1:
The patent implements a continuous reaction process where platform compounds are converted through decarboxylation, oligomerization, and aromatization in sequence without intermediate isolation. This continuous action maintains optimal reaction conditions throughout, maximizing carbon conversion to desired aromatic products while minimizing carbon loss to gases or coke deposition. The integrated process ensures that carbon atoms from biomass are efficiently channeled through each reaction stage to final aromatic products.
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 significantly increases the yield and selectivity of xylene, achieving up to 86.5% yield and 94% selectivity, while also extending catalyst service life and reducing carbon deposition, leading to a more efficient and cost-effective production of aromatics.
Implementation Method 1
contacting a compound having a lactone group with a decarboxylation catalyst, under decarboxylation reaction conditions, to produce a C4 olefin
Implementation Method 2
contacting the C4 olefin with a dimerization catalyst, under dimerization reaction conditions, to produce a C8 olefin
Implementation Method 3
contacting the C8 olefin with an aromatization catalyst, under aromatization reaction conditions, to produce an aromatic product
Data Source
AI summary
The present invention relates to a process for producing aromatics, a process for producing p-xylene and terephthalic acid, and a device for producing aromatics. The process for producing aromatics at least comprises a step of producing C8 olefin from a compound having a lactone group and a step of producing aromatics from the C8 olefin. The process for producing aromatics has the characters of high yield of aromatics and high selectivity to xylene.