Floating Semi-Permeable Membrane Bioreactor for Scalable Microalgae Culture

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Solution Overview

Problem

Current photobioreactors for mass-culturing marine microalgae are expensive, require significant space, and incur high operational costs due to the need for separate culture media and lighting units, making them economically unfeasible for large-scale commercial production of bio-energy and carbon dioxide removal.

Innovation Solution

A photobioreactor using a semi-permeable membrane culturing bag that allows seawater to pass through while keeping microalgae contained, allowing natural sunlight exposure and eliminating the need for separate culture media, with a floating unit that maintains the bag's shape and allows for expansion, reducing spatial and operational costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional photobioreactor with glass construction and artificial lighting is used, then microalgae culture is effective for small-scale study, but manufacturing costs and operational costs increase significantly when scale is expanded

Engineering Contradiction:
Improvemicroalgae culture effectivenessVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive glass photobioreactors with disposable plastic bags that can be discarded after use. This eliminates the high manufacturing and maintenance costs of glass reactors while maintaining adequate functionality for mass culture, directly resolving the cost contradiction at scale.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The system uses natural sunlight instead of artificial lighting, and natural seawater instead of prepared culture media. This eliminates the need for expensive lighting units and media preparation systems, allowing the system to serve itself using free environmental resources.

Inventive Principle:
Principle #25Self-service

2Reliability

If a traditional photobioreactor is used, then microalgae culture is adequate for small scale, but wide space is required and expansion is limited

Engineering Contradiction:
Improvemicroalgae culture effectivenessVSAvoidspace requirement
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent transitions from two-dimensional surface-based photobioreactors to three-dimensional volumetric culture using floating bags. This allows space utilization in the vertical dimension and enables scaling without proportionally increasing footprint area, resolving the space contradiction.

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

3Reliability

If a traditional photobioreactor is used, then microalgae can be cultured, but operation costs for lighting unit, culture media preparation and replacement are high

Engineering Contradiction:
Improvemicroalgae culture effectivenessVSAvoidoperational cost
Core Design Contradiction:
ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The system eliminates the need for artificial lighting by using natural sunlight, and eliminates culture media preparation and replacement by using natural seawater. This makes the system self-sufficient using free environmental resources, directly resolving the operational cost contradiction.

Inventive Principle:
Principle #25Self-service

4Productivity

If photobioreactor scale is expanded, then mass production capacity increases, but manufacturing cost and maintenance cost increase

Engineering Contradiction:
Improvemass production capacityVSAvoidmanufacturing and maintenance cost
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent divides the culture system into multiple independent small-scale floating bags instead of one large expensive reactor. Each bag can be manufactured cheaply and discarded individually, allowing scalable mass production without proportionally increasing manufacturing and maintenance costs.

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

Enables low-cost, scalable, and economically viable mass-culture of marine microalgae by utilizing seawater as a culture medium and light source, reducing manpower and operational costs, and allowing for efficient carbon dioxide removal and bio-energy production.

Implementation Method 1

a culturing bag (10-1) made of a semi-permeable membrane which allows seawater to pass through, but prevents passing through of the marine microalgae

Methodology Applied
Scientific EffectSemi-permeable membrane filtration: Semipermeable Membrane

Implementation Method 2

a floating unit (30) connected to the culturing bag (10-1) to dispose the culturing bag near a water level, thereby exposing the culturing bag (10-1) to sunlight

Methodology Applied
Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Implementation Method 3

there is a rising interest in the photosynthesis of microorganisms or microalgae due to functional diversity

Methodology Applied
Scientific EffectPhotosynthesis: Photosynthesis

Data Source

PatentEP2360235B1Photobioreactor for a large-scale marine microalgal culture using semi-permeable membrane
Publication Date: 2016.09.07 INHA UNIV RES & BUSINESS FOUNDATION
  • EP2360235B1 patent drawingFigure 1~2
  • EP2360235B1 patent drawingFigure 3~4

AI summary

Provided is a photobioreactor for mass-culturing marine microalgae using a semi-permeable membrane. The photobioreactor installed in a floating type on a water level or immersed at a predetermined depth from the water level to mass-culture isolated marine microalgae includes a culturing bag formed of the semi-permeable membrane wherethrough seawater may pass, but the marine microalgae can not pass, the culturing bag being configured to provide a three-dimensional culturing space for accommodating the marine microalgae; and a floating unit connected to the culturing bag to dispose the culturing bag near the sea level, thereby exposing the culturing bag to sunlight. Since the photobioreactor for mass-culturing the marine microalgae using the semi-permeable membrane is provided, the photobioreactor may be manufactured at a low cost and free from the spatial restrictions, thereby enabling the expansion of the photobioreactor in both the horizontal and vertical directions. Furthermore, the manpower and costs for managing and operating the photobioreactor may be significantly reduced without producing, supplying, and replacing the culture media to easily and economically mass-culture the microalgae. Thus, the photobioreactor may enable the mass production of useful products including bio-energy and removes stumbling blocks of the commercial mass-production while mass-producing the useful products including the bio-energy.