Gallium Catalyst for Propane Dehydrogenation
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Solution Overview
Problem
Current propane dehydrogenation processes are limited by thermal cracking during long hot residence times, restricting overall propane conversion and propylene yield, necessitating a catalyst that provides high selectivity to propylene, stability at high temperatures, straightforward regeneration, and low manufacturing costs.
Innovation Solution
A dehydrogenation catalyst comprising gallium on an amorphous and non-acidic alumina-phosphate or silica-alumina-phosphate support, optionally with platinum, which is calcined to achieve high mesoporosity and selectivity to propylene with minimal side-reactions, and is used in a process where the catalyst is heated to provide thermal energy for the reaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional propane dehydrogenation processes are used with long hot residence times, then thermal energy is provided for the reaction, but thermal cracking occurs that limits propane conversion and propylene yield
Solution Approach 1:
The patent extracts the harmful thermal cracking function from the heating process by using a circulating catalyst that is heated separately in a regenerator and then passed to the reaction zone. This separates the thermal energy provision from the residence time in the reaction zone, eliminating thermal cracking while maintaining the necessary thermal energy for dehydrogenation.
Solution Approach 2:
The circulating catalyst acts as an intermediary carrier of thermal energy. It is heated in the regenerator using air combustion, then transports this thermal energy to the reaction zone where it provides the necessary heat for propane dehydrogenation without requiring long hot residence times that cause thermal cracking.
2Speed
If high temperatures are used to drive dehydrogenation, then reaction rate increases, but catalyst stability and selectivity deteriorate due to thermal cracking
Solution Approach 1:
The patent changes the operational parameters by using a circulating catalyst system that allows short residence times at high temperatures. The catalyst is rapidly cycled between the reaction zone and regenerator, enabling high reaction rates without prolonged exposure to conditions that cause deactivation and loss of selectivity.
3Productivity
If catalysts with high dehydrogenation activity are used, then propylene production increases, but manufacturing cost increases
Solution Approach 1:
The patent implements a continuous catalyst circulation system where the catalyst is regenerated in situ in the regenerator by burning off coke deposits with air. This eliminates the need to discard and replace deactivated catalyst, reducing manufacturing costs while maintaining high propylene production through continuous catalyst activity.
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 achieves higher catalytic conversion of propane to propylene with reduced thermal cracking, maintaining stability and selectivity at high temperatures, and offers a cost-effective solution for improved dehydrogenation processes.
Implementation Method 1
A de-hydrogenation catalyst is provided that has low cracking activity. The catalyst comprises gallium on an essentially non-acidic and amorphous alumina-phosphate or silica-alumina-phosphate support
Implementation Method 2
an improved process, where circulating catalyst instead of feed stream is heated and provides thermal energy for the dehydrogenation reaction
Data Source
AI summary
A de-hydrogenation catalyst and its use in dehydrogenation of hydrocarbons. The catalyst has low cracking activity and comprises gallium or gallium and platinum on an essentially non-acidic and amorphous alumina-phosphate or silica-alumina-phosphate support with an empirical chemical composition of [Al2O3][SiO2]Y[P2O5]Z, wherein Y is between 0 and 0.2 and Z is between 0.01 and 1.1, with a BET surface area above 50 m2/g, as measured by N2 adsorption experiment.