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Table 1 Bio-energetic product yields, utility demands and energy efficiencies (optimized by pinch point analysis) (CD/CHPSC – Ethanol Production with Conventional Distillation with energy generation from pretreatment residues using CHPSC; CD/BIGCC – Ethanol production with Conventional Distillation with energy generation from pretreatment residues using BIGCC; VD/CHPSC – Ethanol Production with Vacuum Distillation with energy generation from pretreatment residues using CHPSC; VD/BIGCC – Ethanol production with Vacuum Distillation with energy generation from pretreatment residues using BIGCC; CHPSC-EE – Exclusive electricity generation from residues using CHPSC; CHPSC-EE (Dryer) – Exclusive electricity generation from residues using CHPSC where biomass is dried; BIGCC-EE – Exclusive electricity generation from residues using BIGCC)

From: Techno-economic comparison of ethanol and electricity coproduction schemes from sugarcane residues at existing sugar mills in Southern Africa

  Ethanol cogeneration Exclusive electricity
Scenarios CD/CHPSC CD/BIGCC VD/CHPSC VD/BIGCC CHPSC-EE CHPSC –EE (Dryer) BIGCC-EE
Net Outputs
Bioethanol Production (l/hr) 9601 9577 9599 9575    
Electricity Production (MW) 22.06 33.94 23.42 46.47 51.00 55.85 88.63
Steam Generation and Requirements
Gross Steam Generation (tons/hr) 204.58 146.43 204.58 146.42 277.22 294.71 191.98
Mill Steam Demand (tons/hr) 120.00 120.00 120.00 120.00 120.00 120.00 120.00
Ethanol Generation Steam Demand (tons/hr) 51.06 51.06 30.25 30.25    
Steam Contingency (tons/hr) 33.53 −24.63 54.34 −3.83 157.22 174.71 71.98
As percentage of Total Steam Demand 19.60 −14.40 36.17 −2.55 131.02 145.59 59.99
Electricity Generation and Requirements
Gross Electricity Generation (MW) 38.52 187.50 40.76 187.51 65.49 70.50 263.36
Power (MW) 1.17 122.63 1.36 122.63 2.00 2.15 162.24
Ethanol Utilities (MW) 2.81 18.44 3.49 5.91    
Mill Electricity Demand (MW) 12.49 12.49 12.49 12.49 12.49 12.49 12.49
Net Energy Efficiency 25.57% 29.17% 25.98% 32.91% 15.44% 16.86% 26.83%