Technoeconomic analysis of corn stover to transportation fuels via fast pyrolysis and

enzymatic hydrolysis-fermentation

Prepared by: Alec SlungaardUW – Madison

Chemical Engineering

Cellulosic Biofuels

Biofuel production goal: 16 billion gallons/yr by 2022

2010 20220

500

1000

1500

2000

Cellulosic Biofuel Production Rates

Production Rates

Year

Mg

al/

yr

Enzymatic hydrolysis-fermentation is the preferred conversion method High production rates

Pyrolysis alternative – small-scale combustion sites with a centralized hydroprocessing facility

Collaboration is necessary for first cellulosic biofuel plant

Key Points

Corn is composed of two separable sub-units

Corn Cob Corn Stover

No full-scale commercial plants

Enzymatic Hydrolysis-Fermentation

Pyrolysis

Process Efficiency

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It is 10 times cheaper to use coal or natural gas to produce steam than burn the solid waste products

Production Analysis

Table 2—Product analysis of pyrolysis and EHF

Process Product Yield Fuel Production Operation time

Enzymatic Hydrolysis-fermentation (EHF)a

89.8 gal/ton 69.3 Mgal/yr 350 d/yr

Pyrolysisb 88.2 gal/ton 58.2 Mgal/yr 330 d/yr

Sources: a) Aden; b) Anex

Nth plant: benefits from the experience gained through construction and start-up of the first plant

Product Value (PV): combines operating costs and product yield into a quantitative assessment

Nth plant analysis and product value

Economic Analysis

Table 3—Total capital investment and product value for biomass-to-liquid fuelProcess Scenario Total capital

investment ($ millions)Product value ($/GGE)

EHF 380 5.05EHF (pioneer plant) 886 8.75

Pyrolysis 200 2.11

Pyrolysis (pioneer plant)

585 3.41

Source: Anex (2010)    

Enzymatic hydrolysis-fermentation is better suited to achieve the goal of 16 billion gallons/yr

Pyrolysis alternative – small-scale combustion sites with a centralized hydroprocessing facility

Pioneer plants are prohibitively expensive Collaboration could prove to be successful

Recommendation

Questions?

Discussion Questions

1.What are some other possible alternatives to pyrolysis?

2.Does anyone have any first-hand experience with this industry?

3.With the 2022 deadline approaching, does it make sense to explore other options?