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Table 7 Analysis of the main costs and energy balance of corn-to-ethanol in this study

From: Replacing process water and nitrogen sources with biogas slurry during cellulosic ethanol production

  Fresh water Biogas slurry
Amount Costs (RMB) Energy (kJ/kg) Amount Costs (RMB) Energy (kJ/kg)
Main process inputs
 Corn straw 1000 kg 300a 16,350 1000 kg 300a 16,350
 NaOH 134 kg 335b 148.91 134 kg 335b 148.91
 Process water 10 m3 30c 42.0 0 m3 0 0
 Biogas slurry 0 m3 0 0 10 m3 0 0
 Nitrogen source 18 kg 180d 753.48 0 kg 0 0
Total costs (RMB) − 845   − 635  
Total energy input (MJ/kg corn straw)   − 17.29   − 16.5
Main process outputs
 Ethanol 95.2 kg 761.6e   86.8 kg 694.4e  
 Ethanol (Yuan/kg)   8.88    7.32  
Net profit (Yuan)   − 83.4    59.4  
Total energy output (MJ/kg corn straw)    2.83f    2.58f
Net energy value (MJ/kg corn straw)    − 14.46    − 13.92
  1. a, b, c, dThe costs of corn straw, NaOH, process water, biogas slurry, and nitrogen source are calculated based on the fact of China
  2. eThe output of ethanol is calculated as 8.0 Yuan/kg
  3. fEnergy value based on lower heating value