Forced Dynamic Ammoxidation for Flexible Acrylonitrile Production
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Solution Overview
Problem
Existing acrylonitrile production methods face challenges in scalability, particularly for small-scale and decentralized production, with high infrastructure costs and inefficiencies in responding to market demand fluctuations, and there is a need for improved catalysts that enhance productivity and yield.
Innovation Solution
The use of forced dynamic operation (FDO) over transition metal promoted bismuth molybdate-based catalysts in the ammoxidation of propene, which involves periodically varying reactor inputs or conditions to optimize catalyst performance, including alternating gas phases and oxygen concentrations, enhancing acrylonitrile yield and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If steady-state operation is used for acrylonitrile production, then large-scale production capacity is achieved, but infrastructure investment is large and flexibility to market demand fluctuations is poor
Solution Approach 1:
The patent implements dynamic operation by periodically switching between reduction atmosphere (high propene, low oxygen) and oxidation atmosphere (low propene, high oxygen) conditions. This dynamic switching allows the catalyst to cycle between reduced and oxidized states, enabling the system to adapt to varying production demands while maintaining high productivity, thus resolving the contradiction between large-scale production capacity and flexibility to market demand.
Solution Approach 2:
The patent employs periodic alternation between two operational phases: a reduction phase where the catalyst is regenerated with lattice oxygen, and an oxidation phase where acrylonitrile is produced. This periodic action enables the system to maintain high average productivity while being adaptable to market fluctuations by adjusting the duty cycle and duration of each phase, effectively resolving the contradiction between sustained production capacity and operational flexibility.
2Productivity
If traditional ammoxidation process is used, then acrylonitrile is produced, but catalyst performance and productivity are limited
Solution Approach 1:
The patent fundamentally changes the operational parameters by implementing dynamic switching between reduction and oxidation atmospheres, rather than maintaining steady-state conditions. This parameter change enables the catalyst to access different active states with enhanced activity and selectivity, significantly improving both productivity and reliability of acrylonitrile production compared to traditional ammoxidation processes.
Solution Approach 2:
The patent performs preliminary reduction of the catalyst in a controlled atmosphere before the main oxidation reaction. This preliminary action regenerates the catalyst surface and prepares it in an optimal state for subsequent acrylonitrile production, enhancing both catalyst performance and productivity while preventing deactivation that would occur under continuous oxidation conditions.
3Productivity
If high oxygen concentration is maintained continuously, then oxidation reactions proceed, but catalyst deactivation and energy consumption increase
Solution Approach 1:
The patent implements periodic switching between low-oxygen reduction phases and high-oxygen oxidation phases. During the reduction phase, oxygen concentration is minimized to prevent catalyst deactivation and reduce energy consumption. During the oxidation phase, high oxygen concentration is applied only when needed for acrylonitrile production. This periodic action maintains high overall productivity while significantly reducing average energy consumption and preventing continuous catalyst deactivation.
Solution Approach 2:
The patent dynamically adjusts oxygen concentration based on the operational phase rather than maintaining a constant high level. The oxygen concentration is kept low during reduction phases to minimize energy consumption and catalyst stress, then rapidly increased during oxidation phases to maintain high reaction rates. This dynamic control resolves the contradiction between maintaining oxidation reaction rate and reducing energy consumption.
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
FDO improves acrylonitrile productivity and yield, reduces energy consumption, extends catalyst lifetime, and allows for rapid adjustments to market demand, making it suitable for low-volume and decentralized production.
Implementation Method 1
The forced dynamic operation leverages catalyst lattice oxygen in ammoxidation of propene to improved acrylonitrile productivity and yield
Implementation Method 2
The forced dynamic operation leverages catalyst lattice oxygen in ammoxidation of propene
Data Source
AI summary
In one aspect, the disclosure relates to a process for acrylonitrile manufacture using forced dynamic operation over transition metal promoted bismuth molybdate-based catalysts. The forced dynamic operation leverages catalyst lattice oxygen in ammoxidation of propene to improved acrylonitrile productivity and yield. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.