Ethanol production by fermentation
. Construct a flowchart of the process and a separate diagram for one of the fermentation batteries containing two reaction vessels, one pump, and one heat exchanger. Calcu¬late and fill in the component flow rates (lb,„/h) and temperatures of each stream on the chart to the extent possible from the given information.

2. Calculate the feed rate of corn in Ibm/h. Estimate the acreage required to supply this plant with corn. (Mote: According to the U.S. Department of Agriculture, Crop Production, 11/9/78, p. A-3, 101.2 bushels of corn are harvested from an acre.)

3. Calculate the molar flow rate (lb-moles/h) of ethanol product.

4. How much water (combined fresh water and condensates) must be added to the mixing tank to obtain the desired mash volume?

5. The C02 produced as a by-product from the fermentation reactor may be useful if it is recovered in sufficient quantity. Estimate the production rate of C02 in pound-moles per hour and standard cubic feet per minute.

6. What fraction of the dried grains must be recycled to control the moisture content of the grains entering the dryer? What production rate of dried grains can be expected from this process?

7. What is the minimum pressure at which the cooking vessel must operate? What is the pressure to which the mash must be flashed to provide a resultant liquor temperature of 145°F? At what rate (lbm/h) is water vaporized in this step?