EDF R&D Energetic aspects of urban waste treatments Claire Lecointe, Charlotte Barbut 2 nd AWAST Workshop November th, 2001, Rennes

DEPARTEMENT SYSTEMES ENERGETIQUES SUMMARY Introduction  Thermal treatments * Incineration * Thermolysis  Biological treatments * Methanisation * Landfill * Composting  Exergy Conclusion

DEPARTEMENT SYSTEMES ENERGETIQUES Introduction  waste treatments => energy production (steam or gas)  steam or gas => electricity or heat  gas => fuel for buses or injection in natural gas networks  but different outputs  and how to compare ?

EDF R&D Thermal treatments

DEPARTEMENT SYSTEMES ENERGETIQUES Incineration LHV W  s  e =  cg C (T’ ; P 1 ) Q (T ; P 2 ) cc thermal treatment with oxygen (even air excess) ; 900 to 1000°C Waste delivery Combustion Heat recovery (boiler) Slags treatment Smokes treatment Dust removalSmokes cleaningVentilator Steam Electricity Steam Steam sold Electricity sold Selfconsumption turbine alternator

DEPARTEMENT SYSTEMES ENERGETIQUES Outputs  combustion output :  c = C / LHV waste  electric output :  e = W / LHV waste  heat output :  s = Q / LHV waste  co-generation output :  cg =  e +  s Rough estimates => 75 to 90% => 4 to 10% with counter-pressure => 60 to 70%

DEPARTEMENT SYSTEMES ENERGETIQUES Results for 5 french installations

DEPARTEMENT SYSTEMES ENERGETIQUES 191 MJ e /t Electricity consumption : Strasbourg 2MW e 5 MJ e /t 78 MJ e /t 2,7 MJ e /t 50 MJ e /t36 MJ e /t4 MJ e /t 90 MJ e /t 211 MJ e /t Waste delivery Combustion Heat recovery Slags treatment Smokes treatment Dust removalSmokes cleaningVentilator Steam/electricity conversion Steam ElectricitySteam Steam soldElectricity sold Selfconsumption 80% consumption

DEPARTEMENT SYSTEMES ENERGETIQUES Thermolysis Ash cooling Pyrolysis Drying Heating Waste Residues (liquid, solid) Pyrolysis gas (H 2, CO 2, CO, CH 4 …) thermal treatment without oxygen ; 400 to 600°C or 600 to 1000°C

DEPARTEMENT SYSTEMES ENERGETIQUES Development stage No industrial installation in France => no data => Do we keep this process in the project ?

EDF R&D Biological treatments

DEPARTEMENT SYSTEMES ENERGETIQUES Methanisation biological treatment without oxygen ; 35°C or 55°C Waste delivery ReactorPress biogas CH 4, CO 2 solid residues Maturation Centrifugation pressing juice solid residues sludge water excess compost CO 2, H 2 O Energy recovery heating electricity fuel injection in natural gas network heating

DEPARTEMENT SYSTEMES ENERGETIQUES Landfill Waste delivery Deposing and compaction biogas leachate Energy recovery heating electricity fuel injection in natural gas network natural biological decomposition

DEPARTEMENT SYSTEMES ENERGETIQUES Biogaz composition

DEPARTEMENT SYSTEMES ENERGETIQUES Biogas : energy recovery

DEPARTEMENT SYSTEMES ENERGETIQUES Results for methanisation

DEPARTEMENT SYSTEMES ENERGETIQUES Results for landfill Methanisation : biogas 1663 to 2862 MJ LHV /t methanised waste

DEPARTEMENT SYSTEMES ENERGETIQUES Landfill : energy consumption for 1t waste Transport Waste delivery Deposing and compaction leachate heating electricity fuel injection in natural gas network Energy recovery Biogas extraction : 4,9 MJ e 1,3 L fuel Farm building : 0,54 MJ e Heating : 0,045 L fuel

DEPARTEMENT SYSTEMES ENERGETIQUES Landfill : problem of time limits year landfill emissions intensity leachate biogas landfill methane stage controlling stage acceptable concentrations

DEPARTEMENT SYSTEMES ENERGETIQUES Composting  This process doesn’t product any energy but uses it.  It allows material recovery by transforming organic waste in compost which can be used in farming.  Not yet studied because of lack of data. biological treatment with oxygen

EDF R&D Exergy

DEPARTEMENT SYSTEMES ENERGETIQUES Definition Exergy is the maximum part of energy in a system which can be changed in mecanic energy. mecanic and electric energy = pure exergy heat energy = exergy + loss WtWt heat machine  (T) Q Ambient environment (T a ) Carnot engine WcWc Q a = Q * T a / T W g = -Ex (by agreement)

DEPARTEMENT SYSTEMES ENERGETIQUES Exergetic assessment  Carnot factor :  c = 1 - T a / T  exergetic output :  ex =  e +  c  s Rough estimates Paris heating network : 0,432 (T = 240°C and T a = 20°C) Incineration : 33 to 38% towards waste LHV 38 to 45% towards boiler steam Methanisation : 39,8% towards waste LHV 53,5% towards methane

DEPARTEMENT SYSTEMES ENERGETIQUES Conclusion  delicate comparison because of : * different value for burnt and methanised waste * different value for steam and electricity  exergy = solution ?  similar quality measure for waste ?