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Table 4 Use of autohydrolysis of mixed Southern hardwoods to produce sugar-laden hydrolysate and autohydrolysis residue

From: Integration of pulp and paper technology with bioethanol production

Comparison of autohydrolysis options

Hardwood Pretreatments

 

Mixed Southern hardwood

Mixed Southern hardwood

2-Stage Autohydrolysis

Newsprint Repurpose

 

Quantity

Cost per unit

Quantity

Cost per unit

Mixed Southern Hardwood

454,545

$72.18

454,545

$72.18

Annual Ethanol Production, Liters

141,771,687

 

122,880,735

 

Ethanol Yield, Liters per BDt

312

 

270

 

CAPEX Total/per Annual Liter

213,776,300

$1.50

$117,823,560

$0.96

Total Biomass Cost per Liter

 

$0.25

 

$0.29

Total Enzyme Cost per Liter

 

$0.11

 

$0.12

Total Energy Credit/Cost

 

$0.00

 

-0.01

Total Direct Cost per Liter

 

$0.37

 

$0.43

Total Indirect Cost per liter

 

$0.36

 

$0.33

Total Cash Cost per liter

 

$0.51

 

$0.61

Total Cost per liter

 

$0.73

 

$0.76

M. E. R,$ per liter

 

$0.71

 

$0.73

IRR, 0025

 

12%

 

12%

  1. The residue is mechanically refined to improve accessibility to enzymes. The hydrolysate is treated with ion exchange resins to remove acetic acid, and then combined with the residue for enzymatic hydrolysis (see Figure4).