Copper-Containing Catalyst Precipitation with Silica for Alkali Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing copper-containing catalysts for water-gas shift and methanol synthesis result in catalysts with relatively low initial activity and poor stability, often due to high levels of retained alkali and the formation of detrimental phases like Dawsonite.
Innovation Solution
A method involving the co-precipitation of copper, zinc, and aluminum compounds in the presence of a silica precursor, followed by careful control of pH and temperature, to form a catalyst with a silica content of 0.1 to 5.0 wt%, which includes steps of mixing, washing, drying, and calcining to enhance catalyst performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing precipitation methods are used to produce copper-containing catalysts, then the catalysts can be manufactured with standard procedures, but the catalysts exhibit relatively low initial activity and poor stability due to high retained alkali levels and formation of detrimental phases
Solution Approach 1:
The patent extracts and removes harmful retained alkali from the catalyst preparation process by implementing extensive washing steps (water washing, acid washing) to eliminate alkali metal cations from the catalyst precursor, thereby preventing their negative impact on catalyst stability and performance
Solution Approach 2:
The patent changes the chemical composition parameters by introducing silica precursor (sodium silicate or colloidal silica) at controlled concentrations (0.1-5.0 wt% SiO2) during precipitation, which modifies the catalyst structure to prevent Dawsonite phase formation and enhance stability
2Productivity
If existing precipitation methods are used to produce copper-containing catalysts, then the catalysts can be manufactured with standard procedures, but the catalysts exhibit relatively low initial activity and poor stability due to formation of detrimental phases like Dawsonite
Solution Approach 1:
The patent converts the potentially harmful effect of high pH conditions during precipitation into a beneficial outcome by controlling the precipitation sequence to form copper hydroxide first, then aluminium hydroxide, which prevents Dawsonite phase formation while maintaining high catalyst activity
Solution Approach 2:
The patent changes the precipitation parameters by controlling pH progression and adding silica precursor, which prevents the formation of detrimental Dawsonite phase while promoting the formation of active copper species and high-surface-area aluminium hydroxide support
3Reliability
If silica is included in the precipitation steps to provide 0.1 to 5.0 wt% silica content, then the catalyst exhibits enhanced stability and performance, but the preparation process becomes more complex
Solution Approach 1:
The patent merges the silica addition step with the existing precipitation process by adding silica precursor (sodium silicate or colloidal silica) during the precipitation steps, thereby incorporating silica into the catalyst structure without requiring separate processing steps
Solution Approach 2:
The patent makes the precipitation process multi-functional by simultaneously achieving copper and aluminium precipitation, silica incorporation, and catalyst precursor formation in a single integrated process, eliminating the need for separate treatment steps
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 method produces catalysts with high initial activity and excellent stability, featuring small malachite crystallite sizes and high surface areas, thereby improving long-term performance.
Implementation Method 1
combining an acidic copper-containing solution with a first basic precipitant solution in a first precipitation step to form a first precipitate
Implementation Method 2
combining an acidic aluminium-containing solution with a second basic precipitant solution in a second precipitation step to form a second precipitate
Implementation Method 3
a silica precursor is included in the first precipitation step, the second precipitation step or the precipitate mixing step, to provide a catalyst with a silica content
Implementation Method 4
washing, drying and calcining the catalyst precursor to form the copper-containing catalyst
Data Source
AI summary
A method for preparing a copper-containing catalyst is described comprising the steps of: (a) combining an acidic copper-containing solution with a first basic precipitant solution in a first precipitation step to form a first precipitate, (b) combining an acidic aluminium-containing solution, further comprising one or more metal compounds selected from copper compounds, zinc compounds and promoter compounds, with a second basic precipitant solution in a second precipitation step to form a second precipitate, (c) contacting the first and second precipitates together in a further mixing step to form a catalyst precursor, and (d) washing, drying and calcining the catalyst precursor to form the copper-containing catalyst, wherein a silica precursor is included in the first precipitation step, the second precipitation step or the precipitate mixing step, to provide a catalyst with a silica content, expressed as S1O2, in the range of 0.1 to 5.0 wt %.