Cobalt Catalyst Precursor Calcination Control

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Solution Overview

Problem

The preparation of cobalt-containing Fischer-Tropsch synthesis catalysts often results in varying catalyst activity due to inconsistencies in the calcination process, particularly with regards to space velocity and heating rate, which affect the size and dispersion of cobalt crystallites.

Innovation Solution

A process involving calcination of a loaded catalyst support at a temperature of 220°C with a heating rate below 10°C/minute and a space velocity of at least 19m³/n/kg cobalt compound/hour to produce a cobalt-containing hydrocarbon synthesis catalyst precursor, utilizing a catalyst support with specific pore and modifying components to enhance catalyst performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional calcination is carried out without strict control of heating rate and space velocity, then the process is simpler and faster, but the cobalt crystallite size becomes larger and dispersion decreases, resulting in lower catalyst activity

Engineering Contradiction:
Improvecobalt crystallite size controlVSAvoidcalcination process control
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by strictly controlling the heating rate (below 10°C/minute) and space velocity (at least 19m³/n/kg cobalt compound/hour) during calcination. These parameter adjustments prevent cobalt crystallite aggregation and maintain small crystallite size with high dispersion, directly resolving the contradiction between manufacturing precision and process complexity.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If calcination is performed with high heating rate and low space velocity, then the process is more efficient and faster, but the cobalt crystallites aggregate into larger particles, reducing catalyst activity

Engineering Contradiction:
Improvecalcination efficiencyVSAvoidcatalyst activity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent resolves this contradiction by optimizing two key parameters simultaneously: maintaining a low heating rate (below 10°C/minute) to prevent rapid crystallite growth, while ensuring high space velocity (at least 19m³/n/kg cobalt compound/hour) to maintain good dispersion. This balanced parameter control achieves both acceptable productivity and high catalyst activity.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the calcination process uses uncontrolled heating and gas flow, then the operation is easier and requires less equipment, but the cobalt compound decomposes unevenly, resulting in inconsistent catalyst performance

Engineering Contradiction:
Improvecalcination operation simplicityVSAvoidcobalt oxide composition uniformity
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by controlling the heating rate (below 10°C/minute) to ensure uniform and complete decomposition of the cobalt compound. The controlled slow heating allows consistent transformation to cobalt oxide throughout the support matrix, while the specified space velocity ensures uniform gas distribution. This results in homogeneous catalyst composition and consistent performance.

Inventive Principle:
Principle #35Parameter changes

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

This method yields catalysts with smaller cobalt crystallites, leading to improved activity and performance in hydrocarbon synthesis, specifically in Fischer-Tropsch processes, by optimizing the calcination conditions to achieve higher dispersion and activity.

Implementation Method 1

the calcination involving decomposing the cobalt compound and/or causing the cobalt compound to react with oxygen, the calcination converting the cobalt compound into a cobalt oxide

Methodology Applied
Scientific EffectDecomposition: Decomposition (biological)

Implementation Method 2

the calcination involving decomposing the cobalt compound and/or causing the cobalt compound to react with oxygen

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 3

heating the loaded catalyst support to a temperature, T, of 220°C at a heating rate below 10°C/minute

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 4

effecting gas flow at a space velocity of at least 19m³/n/kg cobalt compound/hour

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2704828B1Process for preparing a cobalt-containing hydrocarbon synthesis catalyst precursor
Publication Date: 2021.05.26 SASOL TECHNOLOGY (PTY) LTD
  • EP2704828B1 patent drawingFigure 1~2

AI summary

A process for preparing a cobalt-containing hydrocarbon synthesis catalyst precursor includes calcining a loaded catalyst support comprising a catalyst support supporting a cobalt compound. The calcination includes subjecting the loaded catalyst support to heat treatment by heating the loaded catalyst support to a temperature, T, of at least 220°C at a heating rate below 10°C/minute, and effecting gas flow at a space velocity of at least 9m3n/kg cobalt compound/hour over the loaded catalyst support during at least part of the heating. The cobalt-containing hydrocarbon synthesis catalyst precursor is thereby produced.