General equation of anaerobic process:

 

 

 

Assumptions:

• The reactor perfectly mixed

• The system is isothermal.

• For n=2,

• Only 20% of food waste is reacted in the reactor.

 

Background information:

• From TESCO, amount of food waste per day is 300kg.

• As the retention time for the digester is around 15 days. Therefore, the feed can be calculated as

 

 

Chemical equation for this project:

 

 

Since only 20% of food waste is reacted in the reactor, therefore the conversion x=0.20

 

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Therefore,

 

 

And the chemical equation can be re-written as:

 

 

 

Mass balance calculation:

 

• Calculate the molecular weight of all component:

 

 

 

 

• Calculate the amount of food waste reacted:

 

 

 

 

 

• Therefore, 

 

 

• Calculate the mass of product produced:

• From the chemical equation, 1 mole of will produce 1 mole of and 1 mole of. Thus, 15kmol feed of will produce 15kmol of methane and 15kmol of carbon dioxide.

 

 

 

 

 

 

• Overall mass balance

 

 

 

 

 

 

• Since the input mass is equal to the output mass, the system fulfill the principle of chemical engineering.

 

• Tabulation of data: