Investigation about Bone Powder as an Alternative Fuel for Circulating Fluidized Bed Combustion

Transcription

1 Investigation about Bone Powder as an Alternative Fuel for Circulating Fluidized Bed Combustion Dr. Leo S. Morf GEO Partner AG Umweltmanagement, Zürich

2 Animal Waste in Switzerland: From Resource to Waste Sudden Disposal Crisis End of year 2000: measures to control BSE Animal waste (Fat, Meat, Bones, Horn) Recycling Disposal Switzerland: Meat powder: t Bone powder: t Animal fat: t Fluidized bed incinerator as an alternative

3 Goal of the Investigation Proof, that the sludge fluidized bed incinerator HARD in Winterthur, Switzerland is suitable for the cocombustion of bone powder no increased environmental loads appear due to feed of this additional fuel.

4 Sludge fluidized bed incinerator ARA HARD (1) Sewage Sludge STEAM PRODUCTION Cleaned Flue Gas Bone Powder NOX-Out Sand COMBUSTION/BOILER FLUE GAS/ WASTE WATER TREATMENT Electrostatic precipitator Acid and Neutral Scrubber Oil Sewer Gas Comb. Air Ash NH3- Stripper Filter Cake Cleaned Waste Water

5 Sludge fluidized bed incinerator ARA HARD (2) Capacity: 3500 kg/h Sewage Sludge (30 w % DS) Steam production (Boiler): 2 t/h Steam: 33 bar / 355 C Energy production: kw hot water (130 C/75 C) - Electricity: 190 kw Combustion chamber temperature: C

6 Bone Powder Bone Powder is a carbon containing Apatit (Dahllit) Composition: Protein: 43 % Fat: 6.6% Water: 2.9 % Phosphat: 23.6% Carbonate: 4.3 % Chlorine: 0.2% Calcium: 18.4 % Heating value: 11 MJ/kg

7 Procedure 1) Definition of experiment (test runs) 2) First Test Run (fuel: only sewage sludge) on the 15th of August 2001: Evaluation of the reference state 3) Test Runs addition of bone powder to sewage sludge - run 1 (24th Sept. 01: 5 w-% bone powder) - run 2 (25th Sept. 01: 15 w-% bone powder) including data collection and sampling procedures 4) Analysis of the samples in the laboratory 5) Data Analysis, Comparision and interpretation of the results

8 Results (1) Input- Mixture Weight-% of the total Waste-Fuel Input Weight-% 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% Bone Powder Sewage Sludge 0% Reference State Run 1 Run 2

9 Results (2) Changes due to Bone Powder Increased bone powder addition results in: a lower auxillary fuel consumption (Sewer Gas, Oil) no siginificant temperature-change in the combustion chamber no increased flue gas NOX-Emissions a lower NOX-OUT -consumption a slightly higher combustion air consumption

10 Result (3) Substances in the Input- Fuels Comparision of Concentrations in Sewage Sludge of Winterthur (KS00/01) Bone Powder () Pb Cd Cr Cu Ni Hg Zn P2O5 Ntot. Concentration in mg/kgds; P2O5 and Ntot. In g/kgds u.g. MW o.g DS: Dry weight Elements

11 Results (4) Quality of Combustion-by-products Fly-Ash Ash Concentration and Bone Powder Concentration in mg/kgds Ptot Porg Ntot Norg Cl Pb Cd Cr Cu Ni Elements Hg Zn Increase of P (total and organic), Cl and Hg Decrease of N (organic), Pb, Cd, Cr, Cu, Ni and Zn No change for N (total)

12 Results (5) Fly ash leaching tests Comparision of Fly Ash Leaching Concentrations Limit Values for the SWISS Residue Landfill Type Concentration in mg/l Pb Cd <0.01 <0.001 <0.1 <0.01 <0.05 Cr Cu Ni Hg Zn Ammonium Cyanid Nitrit Phosphat No value above Emission Limit Increase for Cu, Ni, Zn Decrease for Pb, Cr, Ammonium other Concentrations are below detection limits landfill limit

13 Results (6) Cleaned Waste Water Concentrations Comparision of Cleaned Waste Water Values Emission Limits Conc. in mg/l (Cl: g/l) <0.1 <0.1 <0.1 k.g. k.g. k.g. k.g. k.g. k.g. Ptot Porg Ntot Norg Cl Pb Cd Cr Cu Ni Hg Zn No value above emission limits Increase for N (organic, total), Cl and some heavy metals Decrease for P (total, organic) and Pb, Cd, Cu Emission Limit

14 Results (7) Cleaned Flue Gas Comparision of Flue Gas Values / Bone Powder SWISS Emission Limits (LVR) Concentration [mg/nm3] Reference State ( ) Emission Limit (LVR) 0 CO Nox SO2

15 Conclusions Results demonstrate, that the sludge fluidized bed incinerator HARD in Winterthur, Switzerland is very suitable for the co-combustion of bone powder no increased environmental loads appear due to feed of this additional fuel. The addition of bone powder to sewage sludge up to 15 w-% does not have a negative effect on the operation of the incinerator plant