Calculations

The Gallery below includes screenshots for the most recent calculations as of 4_12_2010
 1)     'Amount of whey needed to create X lbs PLA per year:''

Basis: producing 50 million pounds of Lactic Acid per year which in turn produces X lbs of PLA per year.

Where, LA = Lactic Acid,     L.C. = Lactose Consumed,     L.P. = Lactose Present

2) 'Productivity of Fermentation Process:

Using starting substrate concentration of S0 = (6.24 lb lactose)/(ft3 solution):

Basis: 1 ft3 solution

3) 'Number of fermentation tanks required:

a) Hours of Operation per day: Where,

H.O. = hours of operation, R.T. = Fermentation Run Time, S.T. = Fermentation Startup time

D.T. = estimated downtime between fermentations

b) Assuming tanks will be filled to 80% capacity the number of tanks required is given as:

There you have it ~3 300×103L tanks, each with a seed rermenter. Seed Fermenters will be approximately 1/10 the volume of the Fermenters.

4)     'Cooling water required:

Heat generated (Q) from fermentation ~ 200 Btu/gal broth.

Total broth volume = (300×103L) × (.8) = 240×103L = 63401.29 gal

Cooling Water required:

Where,

Q = heat load in Btu/hr across a single fermenter

m = mass flow rate in lb/hr

V= volumetric flow rate in ft3/hr

5) Bacterial Cell Growth, X

Where,

X = cell concentration

YX/S = mass yield of cells per mass substrate

t = time (in hrs)

6)     Daily shipments required:

Daily Whey requirement:

a) Volume of daily whey requirement:

b) Volume typical shipment can hold:

c) Number of shipments required:

Extra Info:

YP/S = .86

YX/S= .08

% conversion of Lactose to LA by helveticus = 78%

density of whey = 63.64 lb/ft3

μmax = .6 hr -1