Hydrothermal Stable Molecular Sieve Catalyst for Light Olefins
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional processes for producing light olefins, such as steam cracking and catalytic cracking, face challenges in maintaining catalyst stability and activity in severe environments of high temperature and humidity, leading to reduced efficiency and selectivity.
Innovation Solution
A process using a porous molecular sieve catalyst with hydrothermal stability, prepared by modifying the surface pores with a phosphate compound and a water-insoluble metal salt, is employed to produce light olefins from full-range naphtha, maintaining high cracking activity even at lower temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional steam cracking process is used to produce light olefins, then high temperature (800-900°C) is required to achieve cracking reaction, but this leads to high energy consumption and accounts for about 40% of total energy required in petroleum chemical industry
Solution Approach 1:
The patent replaces the thermal cracking mechanism (relying on high temperature thermal energy) with a catalytic cracking mechanism using HZSM-5 zeolite catalyst. The catalyst provides alternative reaction pathways with lower activation energy, enabling cracking at 650-750°C instead of 800-900°C, thus substituting thermal-mechanical energy input with chemical-catalytic action.
Solution Approach 2:
The patent changes the operating temperature parameter from 800-900°C in steam cracking to 650-750°C in catalytic cracking. This parameter change is enabled by the introduction of the HZSM-5 catalyst, which maintains cracking activity at lower temperatures, directly reducing the energy input requirement while maintaining productivity.
2Reliability
If porous solid acid catalyst (zeolite) is used in catalytic cracking process, then catalytic activity is enhanced, but when placed in steam atmosphere of more than 500°C, dealumination of tetrahedral framework occurs causing structural breakdown and rapid reduction in catalytic activity
Solution Approach 1:
The patent acknowledges that steam is necessary for the cracking process but transforms the harmful effect of steam (cause of dealumination) into a beneficial pretreatment step. By conducting steam treatment before use, the catalyst surface is modified to create a more stable structure that resists subsequent dealumination during actual cracking operations, converting the harmful steam exposure into a protective pre-conditioning process.
Solution Approach 2:
The patent applies steam treatment to the HZSM-5 catalyst before actual cracking operations as a preliminary action. This pre-treatment modifies the catalyst surface structure and removes labile aluminum species that would otherwise be rapidly lost during cracking, thereby pre-establishing structural stability and extending catalyst lifetime during subsequent high-temperature steam-containing cracking reactions.
3Productivity
If conventional catalytic cracking process uses HZSM-5 catalyst at reaction temperature of at least 650°C with at least 30% steam in feed, then light olefins can be produced, but the catalyst structure breaks down due to dealumination in steam atmosphere
Solution Approach 1:
The patent applies steam treatment to the HZSM-5 catalyst before actual cracking operations as a preliminary action. This pre-treatment modifies the catalyst surface structure and removes labile aluminum species that would otherwise be rapidly lost during cracking, thereby pre-establishing structural stability and extending catalyst lifetime during subsequent high-temperature steam-containing cracking reactions.
Solution Approach 2:
The patent optimizes the steam content parameter in the feedstock, maintaining it within 10-50% rather than the conventional 30% or higher. This parameter optimization, combined with the catalyst's inherent stability from proper synthesis, allows sustained catalytic activity and structural integrity throughout the cracking process, balancing productivity with catalyst durability.
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 achieves high yield and selectivity of light olefins, with ethylene and propylene content exceeding 30% in the effluent, and maintains catalyst activity after hydrothermal treatment, improving energy efficiency and economic viability.
Implementation Method 1
A process using a porous molecular sieve catalyst with hydrothermal stability, prepared by modifying the surface pores with a phosphate compound and a water-insoluble metal salt, is employed to produce light olefins from full-range naphtha, maintaining high cracking activity even at lower temperatures
Implementation Method 2
a catalyst which, even in an atmosphere of high temperature and humidity, has a relatively stable structure, thereby maintaining its catalytic activity over a long period of time, and shows hydrothermal stability
Data Source
AI summary
Disclosed is a process for producing light olefins from hydrocarbon feedstock. The process is characterized in that a porous molecular sieve catalyst consisting of a product obtained by evaporating water from a raw material mixture comprising a molecular sieve with a framework of Si-OH-Al- groups, a water-insoluble metal salt, and a phosphate compound, is used to produce light olefins, particularly ethylene and propylene, from hydrocarbon, while maintaining excellent selectivity to light olefins. According to the process, by the use of a specific catalyst with hydrothermal stability, light olefins can be selectively produced in high yield with high selectivity from hydrocarbon feedstock, particularly full-range naphtha In particular, the process can maintain higher cracking activity than the reaction temperature required in the prior thermal cracking process for the production of light olefins, and thus, can produce light olefins with high selectivity and conversion from hydrocarbon feedstock.