Table 1 shows an abridged portion of the unit process for processing soybeans to make soy oil, which can be used to make alternative fuels. The table has been normalized per unit of soy oil. For ease of use, all separate energy sources have been aggregated into a single "Energy" flow. In each question below you will seek to find the amount of energy associated with producing soy oil and/or soybean meal using allocation and system expansion methods.

Table 1. Soybean processing

Flow (unit)	Value
Inputs
Soybean (lb)	5.7
Energy (MJ)	6
Outputs (lb)		Price	Energy content
Soybean oil	1	1.05 $/kg	37.2 MJ/kg
Soybean meal	4.48	0.29 $/kg	16.2 MJ/kg

 

1. Allocate the input energy flow to the soybean oil and meal on a mass basis.
2. Assuming a market value for soybean oil and meal are $1.05/kg and $0.29/kg, respectively, allocate the input energy flow to the oil and meal on an economic basis
3. Assuming energy content for soybean oil and meal are 37.2 MJ/kg and 16.2 MJ/kg, respectively, allocate the input energy flow on an energy basis.
    

 

 

 Part 2

The tables below provide alternative production data for soybean processing outputs. Use the data as needed to answer questions d and e via system expansion. Where relevant, consider the case where soybean meal substitutes for two kinds of feed on a protein equivalent basis, and soybean meal has a protein content of 48%. Assume oils are equivalent as substitutes.

Table 2. Protein content and energy use for barley and corn as feed

Feed	Protein Content	Energy Use  (MJ/kg)
Barley	12%	2.4
Corn	9%	2.1

 

Table 3. Life Cycle Energy Use for Producing Palm and Rapeseed Oil

Oil	Energy Use  (MJ/kg)
Palm Oil	8
Rapeseed Oil	18

 

Perform system expansion to compare the energy use of soybean meal and oil production to the energy use of an equivalent meal or oil assuming 1) Soy meal as the determining product; and 2) Soy oil as the determining product. 

1. For each system, draw a figure of the system expansion process. Mark your choices of alternative feeds and oils where appropriate.
2. What is the energy use to produce soy meal in (1)? 
3. What is the energy use to produce soy oil in (2)? 

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