Fluidized Catalytic Conversion With C5+ Recycling for Light Olefins
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Solution Overview
Problem
Existing methods for producing ethylene and propylene face challenges such as low ethylene/propylene ratio, low reaction selectivity, high butylene content, and inefficient energy consumption, failing to meet market demands and resource utilization.
Innovation Solution
A fluidized catalytic conversion method involving high-temperature cracking of olefin-rich feedstock, followed by separation and recycling of C5+ olefins and butylene, using a catalyst with specific temperature, pressure, and time conditions to enhance yield and selectivity, and inhibit byproduct formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If steam cracking is used to produce ethylene and propylene, then the production capacity increases, but the ethylene/propylene ratio is low and cannot meet market demand
Solution Approach 1:
The patent changes the operating parameters of the fluidized catalytic cracking process, specifically using reaction temperatures of 500-750℃ and adjusting the catalyst-to-oil ratio to optimize the ethylene/propylene ratio while maintaining high production capacity
Solution Approach 2:
The patent uses a composite catalyst system comprising zeolite and amorphous silica-alumina with specific ratios and pore structures to achieve selective cracking that improves the ethylene/propylene ratio while maintaining high productivity
2Productivity
If C4 fraction is recycled for further cracking to improve conversion rate, then the ethylene and propylene yield increases, but energy consumption increases and butylene content remains high
Solution Approach 1:
The patent extracts and separates butylene from the product stream using a dedicated butylene separation unit, removing the harmful factor of high butylene content while maintaining the benefits of C4 recycling for improved conversion rate
Solution Approach 2:
The patent recovers and separates valuable butylene as a distinct product stream, converting what was previously a waste stream requiring energy-intensive recycling into a recoverable product that reduces overall energy consumption
3Manufacturing precision
If reaction temperature is increased to improve ethylene/propylene ratio, then the ratio increases, but the production of hydrogen, methane and ethane increases
Solution Approach 1:
The patent employs a composite catalyst with specific acidity and pore structure that enables selective cracking at moderate temperatures, achieving high ethylene/propylene ratios without excessive formation of light gases like hydrogen, methane and ethane
Solution Approach 2:
The patent optimizes the catalyst-to-oil ratio and residence time parameters to achieve high selectivity at moderate reaction temperatures, avoiding the need for high temperatures that would increase light gas production
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 significantly increases the yield and selectivity of light olefins, improves the ethylene/propylene ratio, and reduces the generation of hydrogen, methane, and ethane, optimizing resource utilization.
Implementation Method 1
contacting with a catalytic conversion catalyst having a temperature of 650° C. or higher, and reacting under first catalytic conversion conditions
Implementation Method 2
contacting with a catalytic conversion catalyst having a temperature of 650° C. or higher, and reacting under first catalytic conversion conditions
Data Source
AI summary
A fluidized catalytic conversion method for producing light olefins includes the following steps: 1) introducing an olefin-rich feedstock into a fluidized catalytic conversion reactor, and contacting with a catalyst having a temperature of 650° C. or higher for reaction; 2) separating the reaction product vapor obtained by the reaction to obtain a stream comprising C5+ olefins; and 3) recycling at least a part of the stream comprising C5+ olefins to step 1) for further reaction. The fluidized catalytic conversion method can effectively improve the yield of light olefins, improve the selectivity and improve the ethylene/propylene ratio of the product.