Molybdenum Vanadium Catalyst Crystallinity Control
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Solution Overview
Problem
Current catalysts for producing acrylic acid from propane and/or acrolein by gas-phase catalytic oxidation with molecular oxygen suffer from low selectivity and short catalyst life, leading to decreased yield over time, especially during prolonged industrial-scale reactions.
Innovation Solution
A catalyst with a specific composition and crystallinity range, including molybdenum, vanadium, and additional elements, is prepared by adding an aqueous solution containing component B to an aqueous solution of molybdenum and vanadium, with controlled crystallinity T between 5% and 20% and crystallinity ratio R between 0.06 and 0.30, enhancing catalytic activity and selectivity while extending catalyst life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional molybdenum-vanadium catalysts are used for gas-phase catalytic oxidation of propane and/or acrolein, then catalytic activity is achieved, but selectivity is low and catalyst life is short
Solution Approach 1:
The patent applies parameter changes by precisely controlling the crystallinity of the catalytic active component within the range of 5% to 20% and the crystallinity ratio R within 0.06 to 0.30. This parameter optimization resolves the contradiction by establishing specific crystallinity conditions that simultaneously achieve high selectivity (yield of acrylic acid) and long catalyst life, transforming the conventional approach of using generic molybdenum-vanadium catalysts into a highly optimized catalyst system with controlled crystal structure characteristics
Solution Approach 2:
The patent employs composite materials by creating a catalytic active component with a specific composite structure containing molybdenum, vanadium, and other elements (A, B, C, D) in defined ratios. This composite approach resolves the contradiction by integrating multiple elements with complementary functions to achieve both high selectivity for acrylic acid production and extended catalyst life, rather than relying on a single-element catalyst
2Duration of action of moving object
If catalyst operates for prolonged periods, then production continuity is maintained, but yield decreases over time
Solution Approach 1:
The patent applies the inversion principle by reversing the conventional understanding that catalysts naturally degrade over time. Instead of accepting yield decline as an inevitable consequence of prolonged operation, the patent inverts this relationship by designing a catalyst with controlled crystallinity (5-20%) and crystallinity ratio (0.06-0.30) that maintains stable performance for 8000 hours or more. This inversion transforms the time-yield relationship from negative correlation to positive correlation, where prolonged operation does not compromise yield
Solution Approach 2:
The patent rejects the disposable catalyst approach by creating a catalyst designed for long-term operation. Instead of replacing catalysts after short periods due to deactivation, the patent develops a catalyst with enhanced stability that can operate continuously for 8000 hours or more without significant yield loss, eliminating the need for frequent catalyst replacement and maintaining high productivity throughout the operational period
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 provides stable high-yield production of acrylic acid over a long period, maintaining performance for up to 8000 hours with minimal yield decrease, improving both catalytic activity and selectivity.
Implementation Method 1
a catalyst for producing acrylic acid from propane and/or acrolein by gas-phase catalytic oxidation with molecular oxygen
Implementation Method 2
gas-phase catalytic oxidation with molecular oxygen-containing gas
Implementation Method 3
measured by an X-ray diffraction analysis with Cu-Kα radiation
Data Source
AI summary
A catalyst for producing acrylic acid from propane and/or acrolein by gas-phase catalytic oxidation with molecular oxygen-containing gas, comprising a catalytic active component containing molybdenum and vanadium as essential elements, and having a crystallinity T of 5% or more and 20% or less in the 2θ range of 5° to 90°, measured by an X-ray diffraction analysis with Cu-Kα radiation; and a process for producing acrylic acid by gas-phase catalytic oxidation of propane and/or acrolein with molecular oxygen, comprising the step of conducting the gas-phase catalytic oxidation in the presence of the catalyst. According to the catalyst and the process for producing acrylic acid of the present invention, it is possible to stably produce acrylic acid at a high yield for a long period.