Zeolite Catalyst for Ethylene Propylene Selectivity
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Solution Overview
Problem
Existing methods for producing ethylene and propylene through catalytic conversion with zeolite-containing catalysts face challenges such as high catalyst activity leading to aromatic hydrocarbon conversion, coking degradation, and regeneration degradation, resulting in low yields and unstable operation.
Innovation Solution
A method involving a zeolite-containing shaped catalyst with specific properties, including intermediate pore size, low proton amount, silver content, silica binder, and controlled sodium concentration, is used in a fixed-bed reactor to stabilize catalyst performance and prevent powdering, ensuring efficient and long-term production of ethylene and propylene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If catalyst activity is increased to improve ethylene and propylene production rate, then productivity is improved, but ethylene and propylene are converted into aromatic hydrocarbons through successive reaction, worsening product selectivity
Solution Approach 1:
The patent applies parameter changes by precisely controlling catalyst activity through sodium concentration (50-500 ppm) and contact time (0.5-5 seconds). This optimization allows the catalyst to be active enough for high productivity while preventing over-reaction to aromatics, thus resolving the contradiction between production rate and product selectivity
Solution Approach 2:
The patent implements dynamics by using a continuous regeneration system where catalyst activity is dynamically adjusted. The catalyst is periodically regenerated by burning off coke deposits, maintaining optimal activity levels for ethylene and propylene production while preventing excessive conversion to aromatics
2Reliability
If catalyst activity is decreased to prevent conversion to aromatic hydrocarbons, then product selectivity is improved, but yield of ethylene and propylene becomes low, worsening productivity
Solution Approach 1:
The patent optimizes parameter ranges for catalyst activity (sodium concentration 50-500 ppm) and contact time (0.5-5 seconds) to achieve the best balance. Within this optimized range, the catalyst maintains sufficient activity for high ethylene and propylene yield while preventing excessive conversion to aromatics, resolving the contradiction between selectivity and productivity
3Reliability
If regeneration operation is repeated to restore catalyst activity, then catalyst activity is recovered, but aluminium is released from zeolite crystals causing permanent degradation, worsening catalyst stability
Solution Approach 1:
The patent applies parameter changes by strictly controlling regeneration conditions, particularly limiting oxygen concentration to 0.1-5% and maintaining regeneration temperature below 600°C. These controlled parameters enable effective coke removal and catalyst activity recovery while preventing aluminium release and zeolite crystal degradation, thus resolving the contradiction between activity recovery and structural stability
Solution Approach 2:
The patent implements beforehand cushioning by adding sodium to the zeolite catalyst before regeneration. This sodium acts as a protective agent that cushions against the harsh regeneration conditions, preventing aluminium release and structural degradation while still allowing effective coke combustion and activity recovery
4Productivity
If frequent regeneration is performed to maintain catalyst activity, then productivity is maintained, but regeneration degradation occurs more often, worsening catalyst stability
Solution Approach 1:
The patent optimizes regeneration parameters (oxygen concentration 0.1-5%, temperature <600°C) to enable frequent regeneration cycles without causing structural degradation. These controlled parameters allow the catalyst to be regenerated often enough to maintain continuous productivity while protecting the zeolite crystal structure from aluminium release and permanent damage, resolving the contradiction between continuous production capability and structural stability
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 method achieves stable and efficient production of ethylene and propylene with high resistance to degradation, maintaining catalyst activity and selectivity, and preventing channeling and powdering issues, thus facilitating industrial-scale operation.
Implementation Method 1
contacting a hydrocarbon material that contains at least one compound having from 4 to 12 carbon atoms with a zeolite-containing shaped catalyst in a fixed-bed reactor to thereby carry out catalytic conversion
Implementation Method 2
when an olefin-containing hydrocarbon material is subjected to catalytic conversion with a zeolite-containing catalyst, then a carbonaceous deposit may readily form on the surface of the catalyst (coking)
Implementation Method 3
The catalyst of which the catalytic activity has been lowered by coking degradation may be restored to its original catalytic activity generally by heating it in the presence of an oxygen-containing gas to thereby burn away the coke
Implementation Method 4
steam is formed through the coke combustion, and when zeolite is heated in the presence of the steam, then aluminium that is an active point of zeolite is released from zeolite crystals
Data Source
AI summary
The invention is to provide a catalyst excellent in product producibility and selectivity, and in coking degradation resistance and regeneration degradation resistance, which is for production of ethylene and propylene through catalytic conversion from a hydrocarbon material. The invention relates to a method for producing ethylene and propylene through catalytic conversion from an olefin, by contacting a hydrocarbon material with a zeolite-containing shaped catalyst satisfying the following requirements (1) to (6), in a reactor: (1) the zeolite is an intermediate pore-size zeolite having a pore size of from 5 to 6.5 angstroms, (2) the zeolite does not substantially contain a proton, (3) the zeolite contains at least one metal selected from the group consisting of metals belonging to the Group IB of the Periodic Table, (4) the zeolite-containing shaped catalyst comprises silica as a binder, (5) the zeolite-containing shaped catalyst has a side-crush strength of at least 2.5 N/mm, (6) the zeolite-containing shaped catalyst has a sodium content of 500 ppm or less as an H-exchange type thereof.