Bioreactor Draft Tube Blade Angles Gas Mixing
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Solution Overview
Problem
Conventional bioreactors face inefficiencies in gas dissolution and short residence time of gases in the reaction mixture, limiting the growth of micro-organisms due to large gas bubbles and inadequate mixing.
Innovation Solution
A bioreactor design featuring a draft tube with a smaller inner diameter and height, surrounded by blade structures at specific angles, which breaks down gas bubbles and generates a flow to increase the residence time of the gas-liquid mixture, ensuring efficient mixing and gas utilization by micro-organisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If gases are pumped into the bottom of the bioreactor to dissolve in liquid, then gases are provided to micro-organisms, but the residence time of gases in liquid is short and energy efficiency is reduced
Solution Approach 1:
The bioreactor is divided into distinct functional zones: a gas injection zone at the bottom with spargers for gas distribution, a middle reaction zone for micro-organism growth, and a top gas collection zone. This segmentation allows gases to be introduced at the bottom, rise through the liquid phase for dissolution, and be collected at the top, thereby extending the residence time of gases in the liquid phase without requiring recirculation systems.
2Stability of the object's composition
If Rushton turbines are used to break gas bubbles, then mixing is improved, but liquid free zones form and energy efficiency decreases
Solution Approach 1:
The patent extracts the bubble-breaking function from the traditional Rushton turbine system and relocates it to the gas-liquid interface region. Gas bubbles are broken down as they rise through the liquid phase and enter the gas collection zone, eliminating the need for high-energy mechanical agitation in the bulk liquid and avoiding the formation of liquid free zones.
Solution Approach 2:
The system uses pneumatic principles to break gas bubbles through controlled gas injection and pressure differential as gases rise from the bottom spargers to the top collection zone. The bubble breaking occurs naturally through the gas-liquid interaction and pressure changes, rather than through mechanical means, thereby improving energy efficiency.
3Loss of time
If U-tube arrangement or airlift reactor designs are used to increase residence time, then gas utilization improves, but the systems only support slow growing cultures and do not support intensive microbial growth
Solution Approach 1:
The patent merges the advantages of airlift reactor designs (extended gas residence time through vertical flow) with the capabilities of high-shear mixing systems. The gas injection zone provides intensive mixing for high cell density cultures, while the vertical gas rise path ensures extended residence time, allowing the system to support both intensive microbial growth and efficient gas utilization.
Solution Approach 2:
The system dynamically adjusts the balance between gas injection rate, liquid circulation, and bubble rise velocity to optimize both residence time and mixing intensity. By controlling the gas flow rate and sparger configuration, the system can adapt to different microbial growth rates, supporting both slow-growing and fast-growing cultures effectively.
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 bioreactor design enhances gas-liquid mixing, increases the surface area for gas absorption, and prolongs the residence time of gases within the reaction mixture, leading to improved micro-organism growth and energy efficiency.
Implementation Method 1
means for generating flow of the reaction mixture within the reaction chamber
Implementation Method 2
blade structure... which breaks down gas bubbles and generates a flow to increase the residence time
Implementation Method 3
gases are pumped with a defined pressure from a bottom of the bioreactor, into the liquid contained in the bioreactor... gases are generally used by the micro-organisms in a time the gases rise from the bottom to the top
Data Source
AI summary
A bioreactor for growing micro-organisms, has a reaction chamber containing a reaction mixture with a reaction medium and micro-organisms. A draft tube is arranged inside the reaction chamber, which has a gas inlet, an inlet for the reaction mixture at its first end, and an outlet for the reaction mixture at its second end. The bioreactor includes means for generating flow of the reaction mixture within the reaction chamber and a first blade structure arranged inside the reaction chamber, surrounding the draft tube. The first blade structure has blades arranged at, at least one of an angle α1 with respect to a direction defined by the height of the reaction chamber, or an angle α2 with respect to a direction defined by the height of the reaction chamber. The bioreactor also includes an inlet for reaction medium and an outlet for withdrawing medium with grown micro-organisms.