Oxyborate Oxygen Transfer Agents for OCM and ODH
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Solution Overview
Problem
Current catalysts and oxygen transfer agents for oxidative coupling of methane (OCM) and oxidative dehydrogenation (ODH) of ethane and higher hydrocarbons face challenges in maintaining high conversion and selectivity in fluidized bed reactors while being cost-effective and resistant to deactivation by poisons like hydrogen sulfide and carbon dioxide.
Innovation Solution
A family of oxyborates with the general empirical formula M3BO5 or M2′M″BO5, combined with a magnesia-phosphate cement, is used as an oxygen transfer agent, featuring a metal-boron oxide with an average oxidation state of 2.7+ to 4.0+ and a stoichiometric excess of Mn of 10% or less, which enhances conversion and selectivity in OCM and ODH reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional catalysts are used for OCM and ODH reactions in fluidized bed reactors, then high conversion and selectivity can be achieved, but the catalysts suffer from deactivation by poisons such as hydrogen sulfide and carbon dioxide
Solution Approach 1:
The patent employs composite oxyborate materials with specific crystal structures that combine multiple metal oxides (such as alkali metal oxides, alkaline earth metal oxides, and transition metal oxides) to create a catalyst system that is inherently more resistant to poison deactivation while maintaining high conversion and selectivity in OCM and ODH reactions
2Productivity
If catalysts are designed for high conversion and selectivity, then reaction performance improves, but manufacturing cost increases compared to commercial catalysts like FCC catalysts
Solution Approach 1:
The patent optimizes the compositional parameters of the oxyborate catalysts, specifically controlling the ratios of metal oxides and the oxidation states of metals (average oxidation state from 2.7+ to less than 4.0+), to achieve high conversion and selectivity while using cost-effective raw materials and simplifying the manufacturing process to be comparable to commercial FCC catalyst production
3Stability of the object's composition
If the catalyst maintains fluidization properties at reaction temperatures, then reactor operation is stable, but the catalyst may be prone to agglomeration or excessive attrition
Solution Approach 1:
The patent introduces magnesia-phosphate cement as a binder component that provides localized structural support and strength to the oxyborate catalyst particles, enabling them to maintain fluidization stability while resisting agglomeration and attrition at high reaction temperatures through enhanced mechanical properties at the particle level
4Productivity
If the catalyst is designed for long-term operation (one month or more), then productivity is maintained, but the catalyst may deactivate or lose selectivity
Solution Approach 1:
The patent performs preliminary characterization and optimization of the oxyborate catalyst composition and structure, including controlling the average oxidation state of metals and incorporating specific crystal phases, to pre-establish the catalyst's stability and resistance to deactivation, ensuring sustained productivity and selectivity over extended operation periods of one month or more
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 oxyborate-based oxygen transfer agents demonstrate higher conversions and selectivities, maintaining reactor stability and resistance to deactivation, and are cost-effective, comparable to commercial fluid catalysts like FCC catalysts.
Implementation Method 1
These conversions may be done either catalytically by feeding a hydrocarbon and an oxygen containing gas, or in a redox oxygen transfer mode whereby an oxygen transfer agent (OTA) supplies the necessary oxygen for the formation of water
Implementation Method 2
Since OCM and most ODH reactions are quite exothermic, a preferred reactor system for these transformations are moving or fluid beds
Data Source
AI summary
An oxygen transfer agent comprising a metal-boron oxide is provided. The average oxidation state of the metal in the metal-boron oxide is about 3+, and has 10% or less of a stoichiometric excess in moles of Mn with respect to the boron. The oxygen transfer agent may further comprise a magnesia-phosphate cement. The oxygen transfer agent is capable of oxidatively dehydrogenating a hydrocarbon feed at reaction conditions to produce a dehydrogenated hydrocarbon product and water. The oxidative dehydrogenation can take place under reaction conditions of less than 1000 ppm weight molecular oxygen, or in the presence of more than 1000 ppm weight of molecular oxygen. Also provided are methods of using the oxygen transfer agents, and an apparatus for effecting the oxidative dehydrogenation of the hydrocarbon feed.