Hydrothermal ODH Catalyst Preparation via Pressure Control
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Solution Overview
Problem
Existing methods for producing oxidative dehydrogenation catalysts using hydrothermal treatment are variable, leading to inconsistent catalyst reactivity and reproducibility, particularly in small-scale laboratory procedures.
Innovation Solution
A process involving the preparation of an aqueous slurry with specific molar ratios of Mo, V, and Te salts, followed by hydrothermal treatment in a reaction vessel at controlled temperatures and pressures, with agitation and removal of gaseous byproducts, and subsequent calcination to produce a catalyst with consistent activity and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hydrothermal treatment is used, then catalyst production is achieved, but catalyst reactivity and reproducibility are inconsistent
Solution Approach 1:
The patent applies parameter changes by precisely controlling hydrothermal treatment conditions including temperature (100-250°C), pressure (1-10 MPa), treatment time (1-48 hours), and pH values. These controlled parameter variations produce consistent catalyst phases and improve both reactivity and reproducibility across different production scales.
Solution Approach 2:
The patent employs preliminary action through pre-treatment steps including slurry preparation with specific metal ratios, drying at controlled temperatures (50-150°C), and calcination before hydrothermal treatment. These preliminary actions ensure uniform catalyst precursor formation, which leads to consistent final catalyst properties.
2Reliability
If hydrothermal treatment variables are increased, then catalyst activity may improve, but reproducibility decreases
Solution Approach 1:
The patent implements feedback control by monitoring and adjusting pH values during hydrothermal treatment, controlling treatment duration within specific ranges (1-48 hours), and adjusting temperature and pressure parameters. This feedback mechanism maintains catalyst activity while ensuring reproducible results across different batches and scales.
Solution Approach 2:
The patent applies dynamics by optimizing the interaction between multiple variables including temperature (100-250°C), pressure (1-10 MPa), and treatment time (1-48 hours). The dynamic balance among these parameters allows the system to achieve high catalyst activity while maintaining reproducibility through controlled variability.
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 process results in a catalyst with high selectivity to ethylene, achieving conversion rates of at least 90% and maintaining activity across various reaction conditions, improving the consistency and effectiveness of the oxidative dehydrogenation process.
Implementation Method 1
heating the slurry in a reaction vessel at a temperature from 150° to 185°C at a pressure from 960 kPa to 1300 kPa
Implementation Method 2
simultaneous removal of gaseous byproduct species produced during the reaction
Data Source
Figure 1
AI summary
The preparation of an oxidative dehydrogenation catalyst comprising Mo, V, Nb and Te using a hydrothermal step the activity and reproducibility of the catalyst is improved by conduction the hydrothermal step at higher pressures while permitting gaseous products to leave the reactor. In some instances a condenser may be upstream of the pressure relief valve.