Fermentation Cooling via Evaporative Recycle Loop
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Solution Overview
Problem
Fermentation processes in large reactor volumes with high temperatures and high biomass and fermentation product concentrations face challenges in maintaining a constant temperature, leading to inhomogeneous heating, scale formation, and decreased microorganism activity, with existing solutions like heat exchangers being inadequate and inflexible.
Innovation Solution
A fermentation process where part of the fermentation medium is withdrawn, cooled by evaporation in a pressure vessel to reduce temperature by 1-8°C, and then recycled back to the reactor, eliminating the need for biomass separation and reducing costs and maintaining apparatus requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat exchangers are provided in the reactor to control temperature, then temperature control is improved, but the free reactor volume is reduced and the system becomes more complex and expensive
Solution Approach 1:
The invention extracts the cooling function from the reactor interior to an external cooling loop. A portion of the fermentation medium is continuously withdrawn from the reactor, passed through a cooling exchanger where heat is removed, and then returned to the reactor. This externalizes the heat exchange function, preserving the reactor's free volume while maintaining temperature control.
Solution Approach 2:
The invention introduces a cooling medium as an intermediary substance to transfer heat away from the fermentation medium. The cooling medium flows through the cooling exchanger, absorbing heat from the fermentation medium without directly contacting it, thus enabling indirect heat exchange and maintaining the reactor volume.
2Temperature
If heat exchangers are installed in the reactor for cooling, then temperature control is improved, but the device complexity and cost increase
Solution Approach 1:
The cooling exchanger is designed to perform multiple functions: it serves as both a heat exchange device and a temperature control mechanism. By integrating the cooling function into the existing fermentation process flow (through withdrawal and return of medium), the system achieves temperature control without requiring separate, complex temperature regulation equipment.
Solution Approach 2:
The invention establishes a continuous cooling loop where fermentation medium is continuously withdrawn, cooled, and returned to the reactor. This continuous circulation ensures constant temperature control without intermittent operation, eliminating the need for complex on/off control systems and maintaining stable fermentation conditions.
3Temperature
If cooling capacity is increased to handle large reactor volumes, then temperature control is improved, but the reactor volume available for fermentation is reduced
Solution Approach 1:
The cooling system is segmented into a separate cooling loop that operates independently from the fermentation volume. Instead of placing cooling elements within the reactor that would displace fermentation volume, the system segments the cooling function into an external circuit that processes a portion of the fermentation medium without occupying reactor space.
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
This approach achieves a homogeneous temperature profile, improving fermentation performance by preventing hot and cool spots, reducing scaling, and maintaining microorganism activity while being cost-effective and flexible.
Implementation Method 1
providing the recycle stream comprising biomass to a pressure vessel wherein the pressure is selected such that the temperature of the recycle stream decreases with a value of 1-8°C, as compared to the temperature of the fermentation medium in the fermentation reactor, by the evaporation of water
Data Source
Figure 1~2
AI summary
The invention pertains to a process for manufacturing a fermentation product comprising - fermenting under fermentation conditions in an aqueous fermentation medium in a fermentation reactor a carbohydrate source with a microorganism capable of converting the carbohydrate into a fermentation product, wherein the fermentation product is a salt or a product with a boiling point above the boiling point of water, - during the fermentation process withdrawing part of the fermentation medium comprising biomass from the fermentation reactor in the form of a recycle stream, - providing the recycle stream comprising biomass to a pressure vessel wherein the pressure is selected such that the temperature of the recycle stream decreases with a value of 1- 8º C, as compared to the temperature of the fermentation medium in the fermentation reactor, by the evaporation of water - recycling the cooled recycle stream to the fermentation reactor. It has been found that the process according to the invention makes it possible to obtain a homogeneous temperature profile of the fermentation medium with limited occurrence of hot or cool spots within the reactor. This has been found to result in improved fermentation performance.