Two-Stage Etherification Guard Bed for Catalyst Protection
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Solution Overview
Problem
Existing methods for producing tertiary alkyl ethers face challenges due to impurities in olefinic hydrocarbon feedstock and alcohol that deactivate catalysts, leading to equipment corrosion and by-product formation, and require additional water washing which increases costs and generates wastewater.
Innovation Solution
A method involving a two-stage etherification process with a first reactor system acting as a guard-bed to remove impurities, followed by a second reactor system and a distillation column, where the first catalyst is replaced more frequently than the second, eliminating the need for water washing and reducing capital and operating costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water washing is used to remove impurities from olefinic hydrocarbon feedstock, then catalyst deactivation is reduced, but equipment complexity increases and wastewater is generated
Solution Approach 1:
The harmful impurities (basic nitrogen compounds, ionic metal compounds, deactivators) are extracted from the olefinic hydrocarbon feedstock using a guard bed containing an acidic adsorbent material. This removes the harmful components before they reach the etherification catalyst, eliminating the need for water washing and its associated complexity and wastewater generation.
Solution Approach 2:
An acidic adsorbent guard bed is introduced as an intermediary component between the feedstock and the etherification catalyst. This guard bed acts as a mediator that selectively removes basic impurities and deactivators through acid-base interactions, protecting the main catalyst without requiring water washing equipment.
2Reliability
If water washing is used to remove impurities, then catalyst deactivation is reduced, but loss of substance increases due to wastewater generation
Solution Approach 1:
The harmful impurities are extracted from the feedstock using solid-phase adsorption in the guard bed, eliminating the need for liquid water washing. This prevents the generation of wastewater streams that would otherwise require treatment and disposal, reducing substance loss.
Solution Approach 2:
The purification method changes from liquid-phase water washing to solid-phase adsorption. This parameter change in the purification mechanism eliminates wastewater generation while maintaining effective removal of basic nitrogen compounds and deactivators that would poison the catalyst.
3Reliability
If water washing is used to remove impurities, then catalyst deactivation is reduced, but manufacturing cost increases
Solution Approach 1:
The guard bed extracts harmful impurities through adsorption, replacing the more expensive water washing process. This eliminates capital costs for wash columns and auxiliary equipment, as well as operating costs for water consumption and wastewater treatment, while maintaining catalyst protection.
Solution Approach 2:
The guard bed uses a relatively small amount of acidic adsorbent material that can be regenerated or replaced periodically. This is more economical than continuous water washing operations, as the adsorbent capacity can be restored through thermal or chemical regeneration, reducing both capital and operating costs.
4Reliability
If water washing is used to remove impurities, then catalyst deactivation is reduced, but equipment corrosion increases
Solution Approach 1:
The guard bed removes basic nitrogen compounds and deactivators that would otherwise require water washing. By eliminating the water washing step, the system avoids creating water-saturated hydrocarbon feeds that promote corrosion in production equipment, thereby protecting equipment from harmful corrosive effects.
Solution Approach 2:
The acidic adsorbent in the guard bed is deliberately chosen to be chemically reactive toward basic impurities. This converts the potential harm of acidic materials into a benefit by selectively removing basic nitrogen compounds and deactivators through acid-base reactions, protecting downstream equipment from corrosion while maintaining catalyst activity.
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 high tertiary alkyl ether production efficiency while minimizing catalyst deactivation and equipment corrosion, reducing costs by avoiding water washing and wastewater generation.
Implementation Method 1
supplying alcohol and olefinic hydrocarbon feedstock to a first etherification reactor system containing first catalyst to produce a first reaction effluent
Implementation Method 2
supplying the first reaction effluent from the first etherification reactor system to a second etherification reactor system containing second catalyst to produce a second reaction effluent
Implementation Method 3
supplying the second reaction effluent to a distillation column at a feed-point between a bottom and a top of the distillation column, and taking out the produced ether from the bottom of the distillation column
Data Source
AI summary
A system for producing ether includes a first etherification reactor system containing first catalyst and producing a first reaction effluent when supplied with alcohol and olefinic hydrocarbon feedstock, a second etherification reactor system containing second catalyst and producing a second reaction effluent when supplied with the first reaction effluent, and a distillation column receiving the second reaction effluent at a feed-point between the bottom and the top of the distillation column. The produced ether is taken out from the bottom of the distillation column. Volume of the first catalyst contributing the production of the first reaction effluent is at most 15% of total volume of the first catalyst and the second catalyst contributing the production of the second reaction effluent. The first etherification reactor system acts as a guard-bed reactor which removes unwanted components from the feed and thus protects the second etherification reactor system.