CaO-Ca3Al2O6 Composite Catalyst for Biodiesel Transesterification

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Solution Overview

Problem

Existing biodiesel production methods using homogeneous alkaline catalysts result in contamination, high energy consumption, and increased costs due to the need for separation and purification processes. Additionally, solid base heterogeneous catalysts face issues with stability and deactivation during repeated cycles due to CaO leaching.

Innovation Solution

A mixed oxide composite catalyst comprising CaO and Ca3Al2O6, which is effective in the transesterification of triglycerides, is used. This composite is more stable than traditional CaO-based catalysts, with enhanced resistance to CaO leaching and a longer catalyst lifetime. The catalyst can be reused and is relatively inexpensive to produce.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If homogeneous alkaline catalysts are used for biodiesel production, then the transesterification reaction proceeds efficiently, but the biodiesel becomes contaminated and requires energy-intensive separation and purification processes

Engineering Contradiction:
Improvetransesterification reaction efficiencyVSAvoidenergy consumption for separation and purification
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent replaces homogeneous chemical catalysts with a heterogeneous solid base catalyst (CaO-based material). This substitution allows the catalyst to be easily separated from the reaction mixture through filtration or decantation, eliminating the need for energy-intensive neutralization and washing steps required by homogeneous catalysts. The solid catalyst maintains high catalytic activity while enabling simple physical separation methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The CaO-based heterogeneous catalyst acts as an intermediary that facilitates the transesterification reaction between triglycerides and alcohols. The solid catalyst particles provide active sites for the reaction to occur, and their heterogeneous nature allows them to be easily separated from the liquid reaction mixture, serving as a mediator that enables both efficient reaction and simple separation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If solid base heterogeneous catalysts are used to avoid contamination and simplify separation, then the process becomes more environmentally friendly, but the catalyst deactivates during repeated cycles due to CaO leaching

Engineering Contradiction:
Improvecatalyst stability and reusabilityVSAvoidCaO leaching from catalyst
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent employs composite CaO-based materials where calcium oxide is combined with other substances (such as alumina, silica, or other stabilizing agents). This composite structure prevents CaO from leaching into the reaction mixture while maintaining the catalytic activity. The supporting material provides a stable matrix that anchors the CaO particles, enabling the catalyst to withstand multiple reaction cycles without deactivation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the physical and chemical parameters of the CaO catalyst by controlling its particle size, surface area, porosity, and chemical composition. These parameter changes enhance the catalyst's stability and resistance to leaching. For example, reducing particle size increases surface area and activity, while appropriate calcination temperatures optimize the crystal structure and prevent sintering during reuse.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If CaO-based heterogeneous catalysts are used for biodiesel production, then the catalyst is low-cost and highly active, but the catalyst requires frequent replacement due to deactivation

Engineering Contradiction:
Improvecatalyst activity and conversion rateVSAvoidcatalyst lifetime
Core Design Contradiction:
ProductivityVSDuration of action of moving object

Solution Approach 1:

The patent uses composite CaO-based materials that combine the high catalytic activity of CaO with the structural stability of supporting materials. This composite approach maintains the high conversion rates and productivity associated with CaO catalysts while significantly extending their operational lifetime through multiple reuse cycles without deactivation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes various parameters including CaO particle size distribution, surface area, pore structure, and chemical composition to achieve both high initial activity and long-term stability. Proper control of these parameters ensures that the catalyst maintains its productivity over extended periods and can be reused multiple times.

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

The mixed oxide composite catalyst achieves high conversion rates and reduces impurities in biodiesel production, improving process efficiency and reducing costs. Its enhanced stability allows for longer catalyst life and easier recycling, making the biodiesel production process more economically feasible and environmentally friendly.

Implementation Method 1

reacting a feedstock comprising fatty acid monoglycerides, diglycerides or triglycerides with a C1 to C4 alcohol in the presence of a mixed oxide particulate composite comprising CaO and Ca 3 Al 2 O 6

Methodology Applied
Scientific EffectCatalysis: Catalysis

Data Source

PatentEP3866967B1Mixed oxide composite comprising calcium oxide and tricalcium aluminate
Publication Date: 2025.04.30 UNIV COURT OF THE UNIV OF ST ANDREWS
  • EP3866967B1 patent drawingFigure 1(a)
  • EP3866967B1 patent drawingFigure 1(b)
  • EP3866967B1 patent drawingFigure 2(a)~2(b)

AI summary

The invention relates to a composite oxide comprising CaO stabilised by Ca3AI2O6 (C3A), wherein the composite is in the form of particles. The mixed oxide composite is useful as a catalyst in the transesterification of triglycerides, e.g. in the production of biodiesel. Calcium leaching is more hindered in CaO-Ca3AI2O6 (2Ca/AI) than in CaO-AI2O3.