Dampfsterilisation von Molke in einem Bioreaktor

Ich versuche einen Bioreaktor zu entwerfen, um Zitronensäure mit Molke und Aspergillus Niger herzustellen.

Der erste Schritt in diesem Prozess wäre, Molke mit etwas Dextrose (ca. 10%) in den Reaktor zu geben. Dann sollte diese Lösung sterilisiert werden, und ich dachte darüber nach, eine Chargen-Dampfsterilisation durch direkte Injektion des Dampfes in den Reaktor zu verwenden. Die Sterilisation sollte bei 121 ° C erfolgen.

Ich bin mir nicht sicher, wie ich die Sterilisationszeit und die für ein bestimmtes Reaktorvolumen (ca. 600 m ³ ) erforderliche Dampfmenge berechnen soll . Ich dachte daran, es so zu berechnen, als hätte ich einen 600 m ^{3 großen} Autoklaven, aber ich bezweifle, dass die Annäherung zutrifft. In diesem Fall wäre die Todeskinetik durch die Arrhenius-Gleichung gegeben :

k = A e^{\frac{- E}{R T}}

$k = Ae^{\frac{-E}{RT}}$

I'd need to determine the activation energy, $E$ , the pre-exponential factor $A$ , or some approximation for $k$ . Then, I'd just have to integrate the equations for the heat and hold energy required:

\begin{aligned} \nabla h e a t & = l n (\frac{N_{0} V_{0}}{N_{1} V_{1}}) = \int_{t_{0}}^{t_{1}} k (t) d t \\ \nabla h o l d & = l n (\frac{N_{1} V_{1}}{N_{2} V_{2}}) = k (t 2_{-} t_{1}) d t \end{aligned}

$\begin{align} \nabla heat &= ln(\frac{N_0 V_0}{N_1 V_1}) = \int_{t_0}^{t_1} k(t) dt \\ \nabla hold &= ln(\frac{N_1 V_1}{N_2 V_2}) = k(t2_-t_1) dt \end{align}$

To figure out $t_1$ and $t_2$ .

Am I approaching this problem correctly?

chemical-engineering process-engineering steam

— facuq
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Do you know the SAL you need? My process engineering handbook goes into this, but only briefly and I want to think about it a bit before I give a wrong answer.

— mart

Sterilization can be achieved both with temperature and pressure. Maybe you should investigate the pressure side of the question as well.

— BOB

It all depends on the sterilization level you want to achieve. As you say, you would need to know the death kinetics parameters, or equivalently the log-decimal reduction time (D) and how it changes with temperature (Z). As sterilization is a problem that takes place almost everywhere in food industry, a standard sterilisation cycle lasts for 30 min. at 121 degC at the cold spot of your reactor. This ensures that the spores of many Bacillus, Clostridium and other thermophilic microorganisms cannot survive.
For a 600 m3 reactor the easiest is to have a temperature probe inside of the reactor. As how much steam? That depends on how well isolated your reactor is. The best is to make a feedback loop with setpoint 121 degC that would send steam whenever temperature starts to drop. Otherwise, you can try to do the same manually.

— Toulousain
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