Amorphous Mixed Metal Oxide Catalyst for Low-Temperature Ethylene Selectivity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for converting alkanes to olefins, such as thermal cracking and oxidative dehydrogenation, are either energy-intensive and costly or face challenges in selectivity due to the reactivity of olefins leading to unwanted byproducts.
Innovation Solution
A catalyst composition comprising a mixed metal oxide with the empirical formula Mo1.0V0.12-0.49Te0.05-0.25Nb0.10-0.20AlcOd, where c is from 0 to 2.0, and an adjuvant like alumina, which is at least 40 wt. % amorphous, is used for oxidative dehydrogenation, optimizing conversion temperature and selectivity to ethylene.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If thermal cracking is used to convert alkanes to olefins, then conversion can be achieved, but energy consumption is high and CO2 production is significant
Solution Approach 1:
The patent changes the operational parameters by introducing oxygen into the reaction system, enabling oxidative dehydrogenation to occur at lower temperatures (300-750°C) compared to thermal cracking temperatures. This parameter change allows the reaction to proceed with reduced energy input while maintaining productivity.
Solution Approach 2:
The patent introduces an oxidative dehydrogenation catalyst as an intermediary substance that facilitates the conversion of alkanes to olefins through oxidation. The catalyst mediates the reaction between alkane and oxygen, enabling the transformation to occur at lower temperatures with reduced energy consumption compared to direct thermal cracking.
2Productivity
If oxidative dehydrogenation is used to convert alkanes to olefins, then higher ethane conversion and ethylene selectivity are achieved, but olefin further oxidation to unwanted byproducts occurs
Solution Approach 1:
The patent applies local quality by creating specific chemical environments within the catalyst structure. The catalyst contains specific metal sites (such as Fe, Co, Ni) that are locally optimized for dehydrogenation activity, while other regions provide selectivity control. This spatial differentiation of catalytic properties ensures high ethylene selectivity while minimizing further oxidation of the produced olefin.
Solution Approach 2:
The patent employs composite catalyst materials combining multiple metal components (Fe, Co, Ni) with specific oxides and supports. This composite structure creates synergistic effects where different metal sites work together to achieve high selectivity for ethylene production while suppressing unwanted byproduct formation through the specific chemical interactions between the composite materials.
3Temperature
If oxidative dehydrogenation catalyst is used, then lower reaction temperatures are required, but catalyst development becomes difficult due to olefin reactivity
Solution Approach 1:
The patent segments the catalytic function into distinct active sites within the catalyst structure. By dividing the catalytic activity into separate functional regions (dehydrogenation sites and selectivity control sites), the catalyst can operate at lower temperatures while maintaining stability. This segmentation prevents the entire catalyst from being overwhelmed by olefin reactivity, making it more manageable and easier to manufacture.
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 catalyst composition achieves a 35% conversion temperature of 350-370°C and selectivity to ethylene greater than 90%, reducing energy consumption and minimizing unwanted byproduct formation.
Implementation Method 1
conversion of paraffins can be accomplished using an oxidative dehydrogenation process where a stream of one or more alkanes are passed over an oxidative dehydrogenation catalyst
Implementation Method 2
The composition is at least 40 wt. % amorphous
Data Source
AI summary
Provided in this disclosure are catalyst compositions. The catalyst compositions include an oxidative dehydrogenation catalyst that includes a mixed metal oxide having the empirical formula:Mo1.0V0.12-0.49Te0.05-0.17Nb0.10-0.20AlcOd wherein c is from 0 to 2.0 and d is a number to satisfy the valence of the oxide. The compositions are at least 40 wt. % amorphous as measured by XRD. The disclosure also provides methods of making the compositions.