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Table 2 Consumption and production of major chemicals and products during the willow harvesting, hot water extraction, fermentation and ethanol recovery

From: Life cycle greenhouse gas emissions of ethanol produced via fermentation of sugars derived from shrub willow (Salix ssp.) hot water extraction in the Northeast United States

  Unit Previous land use
Cropland Grassland
Harvesting
 Harvester fuel consumption (leaf-on) L/Mg 5.7 6.0
 Harvester fuel consumption (leaf-off) L/Mg 3.1 3.2
 Harvested biomass (leaf on) 103 Mg/year 315 315
 Harvested biomass (leaf off) 103 Mg/year 269 269
   Energy source
Biomass Natural gas
HWE Input
 Wood chips Mg/day 700 700
 Sulfuric acid Mg/day 3.28 3.28
 Hydrochloric acid Mg/day 0.41 0.41
 Calcium hydroxide Mg/day 3.06 3.06
 Sodium hydroxide Mg/day 0.04 0.04
 Formic acid Mg/day 2.07 2.07
 Flocculant Mg/day 0.15 0.15
 Membrane (8 × 40″) unit/year 1527 1527
 Water 103 Mg/day 4.2 4.2
 Energy requirement (extraction) GJ/day 501 506
 Energy requirement (extract processing) GJ/day 750 758
HWE
Output
 HWE processed wood chips Mg/day 393a 543a
 Sugars Mg/day 97.4 97.4
 Acetic acid Mg/day 17.3 17.3
 Phenolic resins Mg/day 28.0 28.0
 Methanol Mg/day 5.04 5.04
 Furfural Mg/day 3.61 3.61
Fermentation and recovery
Input
 Energy requirement (fermentation) GJ/day 23.0 23.0
 Energy requirement (distillation) GJ/day 304 304
 Initial cell concentration (10% v) g/g sugar 0.044 0.044
Fermentation and recovery
Output
 Ethanol Mg/day 39.6 39.6
Waste treatment
Output
 Waste water Mg/day 1760 1760
 Ash Mg/day 1.86 0.00
Excess electricity
 Electricity GJ/day 134 146
  1. aFewer HWE chips leave the system boundary under the biomass scenario than natural gas, because a fraction of the HWE chips is combusted in a combined heat and power (CHP) system to meet the heat and electricity requirement of the biorefinery