Oxidative Dehydrogenation Catalyst Zoning for Butadiene Heat Control
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Solution Overview
Problem
Existing oxidative dehydrogenation methods for producing 1,3-butadiene face challenges in effectively controlling heat generation within the reactor, leading to catalyst deterioration, reduced conversion rate, selectivity, and yield due to excessive heat accumulation.
Innovation Solution
A catalyst system for oxidative dehydrogenation using a reactor filled with a diluted catalyst in an n-layer structure, where the concentration of the active ingredient AB2O4 gradually increases from the reactants inlet to the products outlet, utilizing a porous support coated with AB2O4 and diluted with fillers like alumina, silica, or zirconia, to control heat distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If oxidative dehydrogenation is performed using a metal oxide catalyst, then butadiene can be obtained in high yield at low temperature, but heat accumulates in the catalyst bed causing catalyst deterioration and reduced catalyst life
Solution Approach 1:
The catalyst bed is divided into multiple zones with different catalyst concentrations. The front zone (near reactant inlet) has lower catalyst concentration to reduce heat generation, while the rear zone has higher catalyst concentration for high conversion. This segmentation prevents heat accumulation that would otherwise deteriorate the catalyst and reduce its life.
Solution Approach 2:
Different regions of the catalyst bed are given different properties: the front zone uses diluted catalyst (lower active ingredient concentration) to control heat generation, while the rear zone uses concentrated catalyst (higher active ingredient concentration) to maximize butadiene production. This local quality differentiation resolves the contradiction between maintaining catalyst life and achieving high productivity.
2Temperature
If oxidative dehydrogenation is performed using a metal oxide catalyst, then reaction can be performed at low temperature, but excess heat promotes side reactions and reduces reaction efficiency
Solution Approach 1:
The catalyst bed is segmented into zones with varying catalyst concentrations. The front zone with lower catalyst concentration limits heat generation to prevent excessive temperature rise, while the rear zone with higher catalyst concentration ensures high reaction efficiency and butadiene production. This segmentation allows the system to maintain low reaction temperature while avoiding side reactions.
Solution Approach 2:
Different zones of the catalyst bed have different catalytic activities: the front zone has diluted catalyst (lower activity) to control temperature and prevent side reactions, while the rear zone has concentrated catalyst (higher activity) to maximize reaction efficiency. This local quality variation resolves the contradiction between low temperature operation and high productivity.
3Productivity
If the concentration of active ingredient in the catalyst is increased to improve conversion rate, then butadiene yield increases, but heat generation increases causing catalyst deterioration
Solution Approach 1:
The catalyst bed is divided into zones with different active ingredient concentrations. The front zone has lower concentration to limit heat generation and protect catalyst stability, while the rear zone has higher concentration to achieve high conversion rate and butadiene yield. This segmentation allows the system to simultaneously achieve high productivity and maintain catalyst stability.
Solution Approach 2:
Different regions of the catalyst bed have different active ingredient concentrations: the front zone has diluted catalyst (lower concentration) to maintain catalyst stability and control heat, while the rear zone has concentrated catalyst (higher concentration) to maximize conversion rate. This local quality differentiation resolves the contradiction between conversion rate and catalyst stability.
4Reliability
If space velocity is controlled to reduce heat generation, then catalyst life is improved, but productivity and yield are reduced
Solution Approach 1:
The catalyst bed is segmented into zones with different catalyst concentrations. The front zone has lower catalyst concentration to reduce heat generation and protect catalyst life, while the rear zone has higher catalyst concentration to maintain high productivity and yield. This segmentation allows the system to achieve both extended catalyst life and high productivity without needing to reduce space velocity.
Solution Approach 2:
Different zones of the catalyst bed have different catalytic properties: the front zone uses diluted catalyst to control heat and extend catalyst life, while the rear zone uses concentrated catalyst to ensure high productivity. This local quality variation resolves the contradiction between catalyst life and productivity, allowing both to be optimized simultaneously.
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
This system effectively manages heat within the reactor, improving conversion rate, selectivity, and yield while maintaining catalyst stability and activity over time, without requiring additional apparatus or altering conventional facilities.
Implementation Method 1
butene and oxygen react in the presence of a metal oxide catalyst to generate 1,3-butadiene and water
Implementation Method 2
since oxidative dehydrogenation of normal butene is an exothermic reaction unlike direct dehydrogenation, reaction can be performed at a low temperature
Data Source
Figure 1~2
AI summary
Provided is a catalyst system for oxidative dehydrogenation, a reactor for preparing butadiene including the catalyst system, and a method of preparing 1,3-butadiene. In the catalyst system for oxidative dehydrogenation, a coating catalyst is diluted with a specific dilution filler and a reactor is filled with the diluted catalyst, or a reactor is filled with a catalyst for oxidative dehydrogenation so that the concentration of an active ingredient included in the catalyst gradually increases in the direction from reactants inlet in which reactants are fed into the reactor to products outlet. The catalyst system for oxidative dehydrogenation can efficiently control heat generated inside a reactor, thereby improving conversion rate, selectivity, yield, and long-term stability of a catalyst.