1.A manufacturing plant is seeking to mix wood chips with corn stover to fire a boiler. The mixture has a target energy content of 18.8 MJ/kg.

What is the percentage of corn stover in the mixture?

Wood chips: 19.5 MJ/kg
Corn Stover: 17.7 MJ/kg
1 MT = 1000 kg
Answer tolerance: ± 1 percentage point

2.The City of Ames (IA) power plant mixes RDF (Refuse Derived Fuel) with coal to generate electricity. The mixture consists of 12.8% RDF. What is the energy content (in BTU/lb) of the resulting mixture?

Coal: 11,643 BTU/lb
RDF: 5,484 BTU/lb
Answer tolerance: ± 50 BTU/lb

3. A biorefinery uses fast pyrolysis to convert hybrid popular (wood chips) into pyrolysis oil. The pyrolysis unit is fed wood chips at a rate of 49 MT/day. How many gallons of pyrolysis oil is produced per day?
1 lb of wood chips yields 0.68 lb of pyrolysis oil.
1 MT = 1 metric ton = 1000 kg = 2204.6 lbs
Pyrolysis oil density = 1280 kg per m3
Answer tolerance: ± 50 gal/day

4. A biorefinery uses fast pyrolysis to convert hybrid popular (wood chips) into pyrolysis oil. The pyrolysis oil is used to fire a steam boiler that consumes energy at a rate of 4,799 kW.
At what rate (MT/day) must the pyrolysis unit be fed wood chips to provide supply the boiler at the required energy rate?

1 lb of wood chips yields 0.71 lb of pyrolysis oil.
1 MT = 1 metric ton = 1000 kg = 2204.6 lbs
Pyrolysis oil density = 1280 kg per m3
Pyrolysis oil energy content = 18 MJ/kg
Answer tolerance: ± 1 MT/day

5. A biorefinery uses fast pyrolysis to convert hybrid popular (wood chips) into pyrolysis oil. One of the byproducts is biochar. The biochar is spread on cropland as a soil amendment.
The pyrolysis unit is fed wood chips at a rate of 74 MT/day. Biochar is spread at a rate of 19 tons per acre.

How many acres are needed to use all the generated biochar if the biorefinery operates for 182 days?

1 MT of wood chips yields 0.12 MT of biochar
1 ton = 2000 lbs = 0.90718 metric tons (MT) = 907.18 kg
Answer tolerance: ± 25 acres