CrZr Catalyst for Steam Cracking Thermal Stability
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Solution Overview
Problem
Conventional catalysts for hydrocarbon steam cracking suffer from low thermal stability at high temperatures, leading to decreased olefin yield and selectivity, as they often melt or lose catalytic activity due to low melting points and volatilization during the cracking process.
Innovation Solution
Development of oxide and phosphoric oxide catalysts represented by formulas CrZrjAkOx and CrZrjAkPlOx, respectively, which include transition metals like Ti, Nb, Mo, V, Co, Ni, W, Fe, and rare earth metals, prepared through a method involving aqueous solution mixing, coprecipitation, reflux-heating, and calcination to enhance thermal stability and olefin yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional catalysts (magnesium oxide, zirconium oxide, calcium aluminate, etc.) are used for hydrocarbon steam cracking, then olefin yield is increased, but thermal stability deteriorates at high temperature causing catalyst melting and activity loss
Solution Approach 1:
The patent applies composite materials by combining multiple metal oxides (magnesium oxide, zirconium oxide, calcium aluminate, manganese oxide, iron oxide, barium oxide, silica, alumina, potassium magnesium phosphate) into a unified catalyst system. This composite structure leverages the complementary properties of each component: magnesium oxide and calcium aluminate provide high-temperature structural stability, while zirconium oxide and manganese oxide contribute catalytic activity for olefin production. The composite nature prevents individual components from melting or volatilizing at cracking temperatures, thereby maintaining both thermal stability and olefin yield enhancement.
2Productivity
If alkali metal oxide or potassium vanadate catalysts are used, then catalytic activity is enhanced, but olefin yield decreases at high temperature due to low melting points and volatilization
Solution Approach 1:
The patent uses magnesium oxide and calcium aluminate as intermediary carrier materials that support the active catalytic components (potassium vanadate, manganese oxide, iron oxide). These intermediary materials have high melting points and thermal stability, forming a stable matrix that prevents the active components from volatilizing at high temperatures. The intermediaries mediate between the need for catalytic activity and the requirement for thermal stability, allowing the catalyst to maintain both properties simultaneously during steam cracking.
3Temperature
If hybrid catalyst (molybdenum oxide, alumina, silica, silicalite, zirconium oxide) is used, then reaction can proceed at low temperature, but thermal stability is very low causing melting or loss of catalytic activity at high temperature
Solution Approach 1:
The patent modifies the thermal stability parameter of the catalyst system by incorporating high-melting-point materials (magnesium oxide, calcium aluminate, zirconium oxide) in optimized proportions. This parameter change allows the catalyst to withstand the high temperatures (800-900°C) required for hydrocarbon steam cracking without melting or losing activity. The compositional adjustment transforms the catalyst from being thermally unstable to thermally robust while maintaining its ability to facilitate cracking reactions.
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 catalysts demonstrate improved thermal stability and significantly increased light olefin yield, particularly propylene selectivity, maintaining catalytic activity even at temperatures above 1000°C, with the phosphoric oxide catalysts showing enhanced conversion rates and yields compared to conventional methods.
Implementation Method 1
preparing a slurry by coprecipitation after adding ammonia water to the aqueous solution
Implementation Method 2
reflux-heating or hydrothermal treating the prepared slurry
Implementation Method 3
preparing an oxide catalyst for hydrocarbon steam cracking by filtering, drying and calcination the slurry of step (c)
Implementation Method 4
These catalysts were known to increase the yield of olefin by acting as a heating medium during hydrocarbon steam cracking
Implementation Method 5
these catalyst components are volatilized by fast circulation of reaction gas, so that the catalyst activity is decreased with respect to the reaction time
Data Source
AI summary
The present invention relates to an oxide catalyst and a phosphoric oxide catalyst for hydrocarbon steam cracking, method for preparing the same and a method for preparing olefin by using the same. More precisely, the present invention relates to an oxide catalyst for hydrocarbon steam cracking represented by formula 1 and a phosphoric oxide catalyst for hydrocarbon steam cracking represented by formula 3 which would be used for the production of olefin such as ethylene and propylene by hydrocarbon steam cracking, and a method for preparing the same. The present invention provides an oxide catalyst and a phosphoric oxide catalyst for hydrocarbon steam cracking that has excellent thermo-stability at high temperature and improved olefin yield.CrZrjAkOx [Formula 1]CrZrjAkPlOx [Formula 3]Wherein, j, k, l and x are as indicated in the description.