Microalgae Culturing via Industrial Gas Cooling and pH Control

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Solution Overview

Problem

Industrial gaseous effluents from cement plants contain inhibiting components that can hinder microalgae growth and lead to metallic element accumulation, making them unsuitable for food or animal feed applications.

Innovation Solution

A process involving the capture, drying, and purification of CO2-rich effluents from cement plants, which includes cooling the effluent to ≤5°C, separating condensate, and injecting the dry, purified CO2 into a photobioreactor with optimized pH control to cultivate microalgae strains like Arthrospira platensis, Chlorella vulgaris, and Nannochloropsis oculata, ensuring safe valorization for food use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If wet industrial gaseous effluent is used directly for carbonation, then CO2 supply is provided, but metallic elements accumulate in algal biomass and growth is inhibited

Engineering Contradiction:
ImproveCO2 supplyVSAvoidmetallic element accumulation
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes harmful metallic elements and water condensate from the industrial gaseous effluent through cooling condensation and separation processes, retaining only the beneficial CO2 for algal carbonation. This resolves the contradiction by selectively removing harmful components while preserving the useful CO2 supply.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary drying and purification system between the effluent source and the algal culture. This intermediary system condenses water vapor and removes metallic contaminants, transforming the harmful wet effluent into a safe dry gas stream for carbonation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If effluent is cooled for drying, then metallic elements and dust are removed, but process complexity increases

Engineering Contradiction:
Improveresidual dust and metalsVSAvoidcooling and separation system
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent utilizes phase transition of water vapor to liquid condensate through cooling, which naturally separates water from the gas stream and carries away metallic elements. This phase change-based separation provides an efficient and relatively simple method for removing contaminants compared to alternative purification technologies.

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The cooling condensation process self-generates the separation mechanism - as water vapor condenses, it naturally entrains and removes metallic particles and dust. The system uses the physical properties of the effluent itself to achieve purification without requiring complex external separation devices.

Inventive Principle:
Principle #25Self-service

3Productivity

If CO2 enrichment is performed, then microalgae growth is enhanced, but pH control becomes critical to prevent acidification

Engineering Contradiction:
Improvemicroalgae growthVSAvoidpH stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements pH monitoring and control as a feedback mechanism to regulate the CO2 enrichment process. By continuously monitoring pH and adjusting CO2 injection accordingly, the system maintains optimal growth conditions while preventing harmful acidification, thus resolving the contradiction between enhanced growth and pH stability.

Inventive Principle:
Principle #23Feedback

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 process effectively recycles cement plant effluents, reduces residual dust and metals, and maintains microalgae quality, allowing for safe use in food and animal feed without metallic element accumulation, while efficiently utilizing waste heat and CO2.

Implementation Method 1

Drying/purifying said gaseous effluent by cooling, causing condensation of the wet fraction

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 2

biomass, such as micro-algae, needs mineral nutrients, but also water, CO2 and light, to carry out photosynthesis

Methodology Applied
Scientific EffectPhotosynthesis: Photosynthesis

Data Source

PatentEP3443070B1Method for culturing microalgae and/or cyanobacteria from industrial gas effluents containing carbon dioxide and facility for implementing said method
Publication Date: 2021.09.15 ITALCEMENTI SPA
  • EP3443070B1 patent drawingFigure 1
  • EP3443070B1 patent drawingFigure 2

AI summary

A method for culturing microalgae and/or cyanobacteria in a photobioreactor (1) of which the carbon-containing source is an industrial gas containing CO2, after treating said gas by cooling, and slaving the introduction of the dry gas thus obtained to the pH of the culture medium. Application to Arthrospira platensis, Chlorella vulgaris and Nannochloropsis oculata. The invention also relates to a facility for implementing said method.