Experiences in using alternative fuels in Europe and Germany Martin Schneider, Düsseldorf Kielce, 13 November 2008
Structure Boundary conditions in waste legislation Use of alternative fuels in the cement industry Emission and quality control Summary
Clinker burning: high temperatures and long residence times
Process Characteristics of cement kilns max. gas temperature of 2000 C gas retention times of up to 8 s at temperatures above 1200 C max. material temperature 1450 C oxidizing gas atmosphere gas retention times in the secondary firing more than 2 s at temperatures of 1100 C
Process Characteristics of cement kilns (II) uniform burnout conditions destruction of organic pollutants no de-novo syntethis of dioxines and furanes sorption of gaseous components like Hg, HCl, SO 2 on alkaline reactants
Waste incineration under control: Strict requirements from European legislation The European Directive on the incineration of waste: harmonizes European legislation for the incineration of waste confirms the important role of coincineration in European waste policy demands an extremely high level of environmental protection
Wastes always serve as raw materials and fuels Example: used tires organic content: fuel Alkalis, Zn Fe inorganic content: raw material SiO 2 CaO, S, Al 2 O 3
Directive 2000/76/EC on the incineration of waste Pollutant C Total dust 30 HCl 10 HF 1 NO x 500 1) /800 2) Cd+Tl 0.05 Hg 0.05 Sb, As, Pb, Cr, Co, Cu, Mn, 0.5 Ni, V Dioxins and furans 0.1 SO 2 50 3) TOC 10 3) daily average values 10 % O 2, dry in mg/m 3 (dioxins ng/m 3 ) 1) new plants 2) existing plants 3) exemptions may be authorized by the competent authority in cases where SO 2 and TOC do not result from the incineration of waste
Alternative fuels in EU cement industry (2004) In 2004 the European Cement industry recovered more than 6 Mio tonnes of waste This corresponded to an average energy substitution rate of about 17 % Source: CEMBUREAU
European fuel mix for clinker burning percentage of thermal energy 60 50 40 30 20 10 CEMBUREAU 2002 CEMBUREAU 2003 CEMBUREAU 2004 0 coal / lignite petcoke other fossil energy carriers alternative fuels
Alternative fuels (examples) Solid alternative fuels e.g. Paper waste Textile waste Carpet waste Plastic waste Rubber waste Waste tyres Fuller earth Waste wood Fractions of domestic waste Sewage sludge Meat and bone meal Liquid alternative fuels e.g. Tar Acid sludge Waste oil Petrochemical waste Varnish residues Chemical waste Waste solvents Distillation residues Wax suspensions Asphalt sludge Oil sludge Gaseous alternative fuels e.g. Landfill gas Pyrolysis gas
Waste fuels in the German cement industry Share of alternative fuels in % 60 50 40 30 20 10 0 1987 1995 1999 2001 2003 2005 2007
Use of alternative fuels in the German cement industry alternative fuels quantity in 2007 [1.000 t/a] used tyres 289 waste oil 85 fractions of industrial wastes (e.g. plastics, paper, textiles, etc.) 1595 meat and bone meal, fat 293 pretreated fractions of municipal wastes 186 scrap wood 13 solvents 100 sewage sludge 254 others, like 90 oil sludge organic distillation residues
Development of the substitution rate for some alternative fuels 35 30 25 pretreated industrial and municipal wastes Mio GJ/a 20 15 10 5 0 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 meat and bone meal used tyres waste oil sewage sludge
Waste fuels for the cement industry - examples plastics dried sewage sludge animal meal of different origin and granularity
Alternative raw materials (examples) Ca-group Si-group Fe-group Al-group Si-, Al-, Ca-group S-group F-group e.g. e.g. e.g. e.g. e.g. e.g. e.g. Industrial lime Lime sludge Foundry sand Pyrite cinder Synth. hematite Red mud Tin slag Waste from the metal industry Fly ash Slag REA gypsum Chemical gypsum CaF 2 -filter sludge Carbide sludge Drinking water sludge Converter dust Mill scale Residues from paper industry Residues from natural stone industry
Alternative raw material - example concrete crusher sand Demands on physical and chemical properties: main components: CaO, SiO 2, Al 2 O 3, Fe 2 O 3 content of chloride, sulphur, alkaline content of trace element and VOC homogeneity moisture access, e. g. seasonal fluctuations handling, e. g. possibilities of storage
Concrete crusher sand three-substance diagram 0 100 40 CaO in % 20 80 60 Composition of already utilised materials 60 SiO 2 in % 40 80 clinker 20 100 0 20 40 60 Al 2 O 3 + Fe 2 O 3 in % 80 0 100
Choice of samples for simulation of clinker burning process 80 40 60 clinker CaO in % 20 0 100 80 60 Concrete crusher sand no. SiO 2 in % 40 20 1 1L 1F 2 3 4 5 100 0 20 40 60 Al 2 O 3 + Fe 2 O 3 in % 80 0 100
CO 2 saving after 3% substitution of natural sand 3,0% 1F decrease of CO2 emissions 2,5% 2,0% 1,5% 1,0% 0,5% 1 1L 3 2 4 5 0,0% 0% 5% 10% savings of primary raw materials
Used tyres
Used tyres
Used tyres
Liquid alternative fuels Regular sampling of liquid alternative fuels is a decisive prerequisite for a sound quality assurance system
Alternative fuels in cement kilns reduce emissions emissionswaste emissions emissions waste coal waste coal landfill or dedicated incinerator + cement plant cement plants
Landfills result in methane emissions Potential of methane emissions (kg CO 2 eq/t) given for European landfills: food wastes 1500 agricultural wastes 1700 textiles 800 paper 1600 plastics 0 uncontrolled landfills emit about 700 kg CO 2 eq per tonne of waste.
Examples for intake materials to be treated Source: Ecowest GmbH
Pretreated alternative fuel Source: Anneliese Zementwerke AG
Pre-treated alternative fuel
Procedure of mechanical-biological treatment mechanical pre-treatment biological treatment fractional flow (optional) mechanical after-treatment energy recovery ca. 30 % of the intake material recycling landfill Source: BMU
Modern pre-treatment plant
Modern pretreatment plant Source: Ecowest GmbH
Emissions have to be measured according to the Directive
Quality of the wastes has to be monitored when needed
Positive experience with alternative fuels and raw materials Cement works utilize selected wastes the intake material must suit the process and the product The question whether an individual waste is hazardous or not is only of minor importance Waste utilization does not cause any rise in the emission level Product quality is not impaired The cement industry is able to deliver a valuable contribution to an environmentally sound waste management
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