Macroporous Inert Material for Acrylic Acid Reactor Pressure Drop
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Solution Overview
Problem
The existing methods for producing acrylic acid via propylene oxidation in fixed bed reactors face issues with increased pressure drop due to the accumulation of particulate impurities and high boiling point byproducts, leading to reduced catalyst lifetime and reactor efficiency.
Innovation Solution
Incorporating an inert macroporous material with specific pore volume and surface area characteristics into the reactor to prevent the formation and accumulation of heavy byproducts and particulate contaminants, thereby maintaining a low pressure drop and extending catalyst life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If propylene oxidation is performed in a fixed bed reactor with mixed metal oxide catalysts, then acrylic acid is produced, but pressure drop increases over time due to accumulation of particulate impurities and high boiling point byproducts
Solution Approach 1:
An inert macroporous material is introduced as an intermediary substance between the reactant gases and the catalyst bed. This material acts as a mediator that captures particulate impurities and high boiling point byproducts (such as phthalic acid) before they can deposit on the catalyst, thereby maintaining stable pressure drop while allowing continuous acrylic acid production.
Solution Approach 2:
The patent employs an inert macroporous material with specific pore volume (at least 0.2 cm³/g) and surface area characteristics. The porous structure provides extensive surface area for trapping particulate contaminants and heavy byproducts through physical adsorption and capillary condensation, preventing their accumulation in the reactor and maintaining reliable pressure drop conditions.
2Productivity
If the reactor operates for extended periods to maximize productivity, then catalyst lifetime is extended, but pressure drop increases rendering the catalyst unusable
Solution Approach 1:
The inert macroporous material serves as a protective intermediary that extends catalyst lifetime by intercepting harmful particulate impurities and high boiling point byproducts. This allows the reactor to operate for extended periods without catalyst deactivation, as the macroporous material accumulates the contaminants instead of the catalyst.
Solution Approach 2:
The inert macroporous material acts as a sacrificial component that can be replaced more easily and cheaply than the catalyst. By allowing the macroporous material to become saturated with particulate impurities and byproducts, the valuable catalyst is protected from fouling, extending its usable life while the macroporous material serves as a disposable filter.
3Productivity
If reactant feed rate is increased to improve productivity, then acrylic acid yield increases, but pressure drop increases due to higher accumulation rate of byproducts
Solution Approach 1:
The inert macroporous material functions as an intermediary that decouples the relationship between reactant feed rate and byproduct accumulation in the catalyst bed. By providing a dedicated trapping medium, it allows higher feed rates to be maintained without proportionally increasing the harmful effects on the catalyst, as the macroporous material absorbs the increased byproduct load.
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 use of inert macroporous materials effectively reduces the formation of phthalic acid and other heavy byproducts, maintaining a stable pressure drop and increasing the catalyst lifetime, allowing for higher reactant feed rates and yields.
Implementation Method 1
feeding the one or more reactant gases or the oxidized gaseous mixture through an inert macroporous material... the inert macroporous material has a pore volume of at least 0.2 cm³/g and a surface area of from 0.5 to 5.0 m²/g
Implementation Method 2
oxidizing one or more reactant gases, such as propylene, in a fixed bed reactor in the presence of a mixed metal oxide catalyst to form an oxidized gaseous mixture
Data Source
AI summary
The present invention provides methods for monomer production, for example, acrylic acid, wherein the methods comprise oxidizing one or more reactant gases, for example, propylene, in a fixed bed reactor, preferably, two fixed bed reactors, in the presence of oxygen and a mixed metal oxide catalyst to form an oxidized gaseous mixture and, at any point in the oxidizing, feeding or flowing the one or more reactant gases or the oxidized gaseous mixture through an inert macroporous material that has a pore volume of from 0.2 cm3/g to 2.0 cm3/g, a surface area of from 0.01 to 0.6 m2/g, and wherein from 30 to 98 wt.% of the total pore volume in the inert macroporous material has a pore diameter of at least 100 µm.