Hybrid Microalgae Raceway with Vertical Photobioreactor Columns

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Solution Overview

Problem

Traditional microalgal cultivation systems face challenges such as contamination, water loss, poor photon capture, and low CO2 absorption due to their design, with closed systems being costly and open systems being inefficient and prone to contamination.

Innovation Solution

A hybrid microalgae cultivation equipment that integrates multiple upright photobioreactor columns within a raceway system, enhancing surface area to volume ratio, CO2 absorption, and gas exchange, while minimizing energy input and operational costs through controlled gas inlets and circulation mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If open pond or raceway systems are used for microalgae cultivation, then construction cost and operational simplicity are reduced, but contamination risk increases and photon capture efficiency deteriorates

Engineering Contradiction:
Improveconstruction costVSAvoidcontamination risk
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent combines open raceway pond advantages (low cost, simplicity) with closed photobioreactor advantages (contamination control, high photon capture) by integrating transparent vertical columns into the open raceway system. The columns are positioned within the raceway to create a hybrid configuration that captures photons more effectively while maintaining open system benefits.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from a two-dimensional open surface system to a three-dimensional structure by adding vertical photobioreactor columns. This increases the surface area to volume ratio and photon capture capability by utilizing vertical space, while the columns remain integrated within the horizontal raceway circulation system.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If open pond or raceway systems are used for microalgae cultivation, then construction cost is reduced, but CO2 absorption capability deteriorates

Engineering Contradiction:
Improveconstruction costVSAvoidCO2 absorption capability
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent adds vertical dimension through tall photobioreactor columns integrated into the horizontal raceway system. This increases the liquid medium height and surface area available for CO2 absorption from the atmosphere, enhancing carbonation capability while maintaining the low-cost open system architecture.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If tubular photobioreactor designs are used for microalgae cultivation, then contamination risk is reduced and photon capture efficiency is improved, but energy consumption increases

Engineering Contradiction:
Improvecontamination riskVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent merges passive open system circulation (using natural convection and minimal pumping) with active closed system photobioreactor columns. The hybrid design reduces reliance on energy-intensive air compressors and centrifugal pumps by utilizing the raceway's natural flow to circulate culture through the vertical columns.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system utilizes natural convection currents and gravity-driven flow to circulate culture medium through the photobioreactor columns, reducing dependence on mechanical pumping systems. The design allows the system to partially self-regulate flow and gas exchange, minimizing external energy input requirements.

Inventive Principle:
Principle #25Self-service

4Ease of manufacture

If traditional raceway design is used for microalgae cultivation, then construction simplicity is maintained, but surface area to volume ratio deteriorates

Engineering Contradiction:
Improveconstruction simplicityVSAvoidsurface area to volume ratio
Core Design Contradiction:
Ease of manufactureVSArea of stationary object

Solution Approach 1:

The patent dramatically increases surface area to volume ratio by adding vertical photobioreactor columns to the horizontal raceway system. The columns provide additional illuminated surface area for photon capture while occupying minimal horizontal space, effectively adding a vertical dimension to the cultivation area.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent segments the cultivation system into horizontal raceway circulation channels and vertical photobioreactor columns. This segmentation allows each component to perform its specialized function while collectively achieving high surface area to volume ratio without compromising construction simplicity.

Inventive Principle:
Principle #1Segmentation

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 hybrid system significantly improves photon capture efficiency, reduces contamination risks, and enhances CO2 absorption, leading to increased biomass productivity and reduced operational costs, while maintaining control over growth conditions.

Implementation Method 1

one or more gas inlets for providing gas bubbles, in use, passing upwards in each of the photobioreactor columns

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 2

a circulation promoting facility for causing liquid growth medium to circulate from the raceway component through the photobioreactor columns to become discharged back into the raceway

Methodology Applied
Scientific EffectPumping: Pump

Implementation Method 3

a flow inducing arrangement for inducing a flow of liquid growth medium within the endless channel of the raceway

Methodology Applied
Scientific EffectFluid flow induction:

Data Source

PatentEP3317393B1Microalgae production process and equipment
Publication Date: 2025.01.15 NELSON MANDELA METROPOLITAN UNIV
  • EP3317393B1 patent drawingFigure 1~2
  • EP3317393B1 patent drawingFigure 3~4
  • EP3317393B1 patent drawingFigure 5~6

AI summary

Microalgae cultivation equipment for the cultivation of microalgae is provided in which a raceway is modified so as to contain multiple generally upright photobioreactor columns spaced apart along its length so as to increase the total surface area of liquid growth medium directly exposed to light and to improve the transfer of CO2 from the gas-phase to the liquid-phase by providing adequate height inside the vertical photobioreactor columns. The lowermost ends of the photobioreactor columns are immersed inside the liquid growth medium in the raceway component and are fed with liquid growth medium by a circulation promoting facility circulating the liquid growth medium from the raceway through the photobioreactor columns to become discharged back into the raceway. Gas inlets provide CO2 containing gas bubbles passing upwards in each of the photobioreactor columns. One or more paddle wheels or jet pumps induce a flow of liquid growth medium within the raceway.