Niobium-Promoted Solid Phosphoric Acid Catalyst Oligomerization
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Solution Overview
Problem
Commercial solid phosphoric acid (SPA) catalysts used in hydrocarbon conversion processes have short run durations due to deactivation and pressure build-up, leading to increased temperatures, undesirable by-products, and lower production rates.
Innovation Solution
A process using a calcined extrudate catalyst comprising a phosphorus source, a silicon source (kieselguhr), and a niobic acid promoter, which enhances the catalyst's stability and efficiency in oligomerization of propylene or butylene by maintaining higher conversion levels and lower deactivation rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If commercial solid phosphoric acid catalysts are used in oligomerization processes, then hydrocarbon conversion can be achieved, but the catalyst runs are short due to deactivation and pressure build-up
Solution Approach 1:
The patent modifies the chemical composition parameters of the SPA catalyst by incorporating specific promoters (metal salts or metal oxides such as niobium, tungsten, molybdenum, vanadium, tantalum, or zirconium) at controlled concentrations (0.1-20% by weight). This parameter change transforms the catalyst's properties to resist deactivation and extend run duration from hours to days or weeks while maintaining conversion efficiency.
Solution Approach 2:
The invention creates a composite catalyst material by combining solid phosphoric acid with promoter compounds (metal salts or metal oxides) and optionally support materials. This composite structure synergistically combines the acid catalysis of SPA with the stabilizing and promotional effects of the metal compounds, resulting in enhanced reliability and extended operational life compared to pure SPA catalysts.
2Quantity of substance
If temperature is increased to maintain conversion during catalyst deactivation, then conversion levels can be maintained, but undesirable by-products increase and coking rate increases
Solution Approach 1:
The promoted catalyst modifies the reaction kinetics parameters, allowing maintenance of high conversion levels (80-95%) at lower temperatures (150-250°C) over extended periods. The promoter presence changes the activation energy and reaction pathway, reducing the need for temperature escalation that would otherwise generate harmful by-products and accelerate coking.
Solution Approach 2:
The promoter compounds transform the deactivation mechanism of the SPA catalyst from a harmful process into a beneficial one. Instead of rapid deactivation requiring temperature compensation, the promoters create a controlled, gradual deactivation profile that maintains activity longer and redirects reaction pathways away from coking and by-product formation, effectively converting the weakness into a strength.
3Quantity of substance
If flow rate is decreased to maintain conversion during catalyst deactivation, then conversion levels can be maintained, but overall production rate decreases
Solution Approach 1:
The promoted catalyst fundamentally changes the time parameter of the reaction by extending active catalyst life from hours to days or weeks. This parameter change allows maintenance of high flow rates throughout the extended run duration while sustaining conversion levels, thereby increasing overall productivity compared to frequent catalyst changes required with conventional SPA.
Solution Approach 2:
The invention enables continuous operation at optimal flow rates and conversion levels for extended periods (days to weeks) without catalyst replacement or regeneration. The promoter-stabilized catalyst maintains consistent activity, eliminating the need to reduce flow rate to compensate for deactivation, thus ensuring continuous high-rate production throughout the extended run.
4Quantity of substance
If higher temperatures are used to compensate for catalyst deactivation, then conversion can be maintained, but coking of the catalyst increases
Solution Approach 1:
The promoter incorporation changes the thermal stability parameter of the catalyst system. The metal promoters (niobium, tungsten, molybdenum, etc.) create thermally stable active sites that maintain conversion efficiency at lower temperatures over time, preventing the temperature escalation that would otherwise increase coking and catalyst deactivation.
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 Nb-promoted SPA catalysts exhibit faster activation, higher conversion levels, and significantly lower deactivation rates compared to commercial catalysts, with improved stability and efficiency in hydrocarbon conversion processes.
Implementation Method 1
Solid phosphoric acid (SPA) catalysts are known for their usefulness in various hydrocarbon conversion processes
Implementation Method 2
the conversion of hydrocarbons is an oligomerization of propylene or butylene
Data Source
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AI summary
The present invention relates to solid phosphoric acid (SPA) catalysts, processes for making the catalysts, and processes for conversion of hydrocarbons using the catalysts, such as oligomerization of propylene. In an exemplary embodiment, the catalyst comprises a calcined extrudate of phosphoric acid, diatomaceous earth, and niobic acid. Methods for converting hydrocarbons to olefins comprise contacting a hydrocarbon feedstock with the catalyst at hydrocarbon conversion conditions