Sorbent materials for the cleaning of sewage biogas in high temperature fuel cell plants 6-9 novembre 2013 Davide Papurello1, Andrea Lanzini1, Federico Smeacetto2, Massimo Santarelli1 1, DENERG, Corso Duca degli Abruzzi, 24, 10129, Turin, Italy. 2, DISAT, Corso Duca degli Abruzzi, 24, 10129, Turin, Italy.
Summary: 1. SOFCOM mission overview 2. Biogas from SMAT (WWTPs) 3. Trace compounds detection 4. Sorbent material apparatus 5. Experimental investigation on cleaning system sorbent materials (effect of biogas water content) 6. Conclusions and future works 2
3 SOFCOM is an applied research project devoted to demonstrate the technical feasibility, the efficiency and environmental advantages of CCHP plants based on SOFC fed by different typologies of biogenous primary fuels (locally produced) also integrated by a process for the CO2 separation from the anode exhaust gases.
SOFCOM layout: Demo plant Air blower Reformer Oxy-combustor Air pre-heater SOFC Cooling CO2 separation Air CHP Cleaning system 4
Biogas from SMAT waste water treatment plant > 6 digesters each 12000 m3, 17-20 day mean residence time; > 33000 Nm3/day biogas (2010) SMAT Castiglione Torinese WWTP Greatest waste water treatment plant in Italy, serving 2.2 millions equivalent inhabitants in Turin metropolitan area (26000 m3/h). Waste water treatment area: 4 parallel lines: biological tertiary treatment with nitrogen and phosphorus removal Sludge treatment line: pre-dewatering, anaerobic digestion, postdewatering, drying. Treats over 6000 m3/day of sludge (2%tss) In absence of oxygen anaerobic microorganisms turn organic substances of sludge into biogas, a mix of methane (60-65%) and carbon dioxide (35-40%). 5
Biogas trace compounds Sulfur compounds: essentially H2S (70-180 ppmv) Chlorine compounds: essentially HCl (100-400 ppbv) Siloxane compounds: essentially D4- D5 (70-400 ppbv) Contaminant SMAT Analysis Feb 2012 DIGESTOR CA 3033 SMAT Analysis May 2012 DIGESTOR CA 3033 DIGESTOR CA 3034 H2S 78,4 148,5 150,6 Total 120 200 220 Alkene % Vol. % Vol % Vol C2H4 1 1,2 1,4 Total chlorine compounds (as HCl) 165.1 211.4 Total 165.1 211.4 Siloxanes ppbv ppbv ppbv 1,1,3,3,5,5-esametiltrisilossano <8 <13 <14,9 decametilciclopentasilossano D5 89.1 277 202 decametiltetrasilossano L4 <8 <13 <14,9 dodecametilpentasilossano L5 <8 <13 <14,9 esametilciclotrisilossano D3 11.4 157 187 esametildisilossano L2 <8 13.7 <14,9 ottametilciclotetrasilossano D4 71.8 253 129 Total 172.3 839.7 553.4 1,2-dichloroethylene (cis) 69.9 N/A N/A 1,2-dichloroethylene (trans) 0.6 N/A N/A 1,2-dichloropropane 2.5 N/A N/A chloroform 0.7 N/A N/A chloromethane <0.13 N/A N/A vinyl chloride <0.119 N/A N/A dibromochloromethane <0.0811 N/A N/A dichlorodifluoromethane <0.114 N/A N/A dioxane 2.8 N/A N/A hexachlorobutadiene <0.13 N/A N/A dichloromethane 8.8 N/A N/A tetrachloroethylene 76.3 N/A N/A trichloroethylene 11.2 N/A N/A trichlorofluoromethane <0.155 N/A N/A Total 172.9 N/A N/A 6
Siloxane compounds H2S Chlorine compounds: 7
Sorbent material apparatus for the sulfur compound removal The experimental set-up adopted for the sorbent material test with simulated biogas HPR 20 MS (CH4/CO2 = 1.5), H2S at 30.72 ppm(v) and demineralized water at 7.28% vol. Heated trap PDMS filter Blank line Filter line Filter CH 4 /CO 2 + H 2 S + H 2 O 8
Experimental investigation on cleaning system sorbent materials Grain Apparent density Relative density Sorbent material dimension Note (kg m-3) (kg m-3) s (µm) Activated carbon, RST3 Norit Zinc oxide, Actisorb S2 ZnO Clariant Activated carbon, Carb-OX Air dep 200-600 2100 100-180 1090 100-180 520 1650 100-180 The best performance are achieved with low fraction of oxygen and water manufacturer Zn, O C, Fe, Cu SEM 10000x SEM 2000x 9
100 90 80 Experimental investigation on cleaning system effect of biogas water content RST3 - H2O 7.28% ZnO - H2O 7.28% Carb-ox - H2O 7.28% C/Co(%) 70 60 50 40 30 20 10 0 100 0 200 400 600 800 1000 1200 1400 1600 180090 Time (s) 80 70 60 50 C/Co(%) 40 30 20 10 RST3 ZnO Carb-ox 0 10 0 200 400 600 800 1000 1200 1400 1600 1800 Time (s)
Conclusions 3 sorbent materials were tested for the H2S removal. (Biogas) Figure depicts the removal performance as the ratio between the outlet concentration (C) and the inlet concentration (C0) of the filter cartridge. The best performance are achieved by ZnO and RST3 activated carbon for the sulfur removal. Carb-ox activated carbon decreases the filer performance around 9% in dry conditions. At stationary conditions this material removes only 30% whereas the other two sorbents 60%. Under wet conditions the filter performance decrease for RST3 and ZnO around 36% and 28% respectively, whereas in case of Carb-ox they improve of +17%. 11
Future works At the moment we are testing the same set-up apparatus with: Single effect of H2S on RST3, ZnO and air-dep sorbent material plus biogas water effect; Single effect of HCl on RST3, ZnO and air-dep sorbent material plus biogas water effect; Double effect of H2S + HCl on RST3, ZnO and air-dep sorbent material plus biogas water effect Further works on the pollutants removal is needed, especially considering chlorines (HCl, C2Cl4) and siloxane (D4) compounds effect and the contemporary presence of water. 12
References Papurello, D, et al. Monitoring of volatile compound emissions during dry anaerobic digestion of the Organic Fraction of Municipal Solid Waste by Proton Transfer Reaction Time-of-Flight Mass Spectrometry. Bioresource Technology 126, 254 265 Papurello, D, et al. Biogas from dry anaerobic digestion of the organic fraction of municipal solid waste: production, cleaning and direct use in a Solid Oxide Fuel Cell. Waste Management (Under revision) www.polito.it/sofcom/ Papurello, D., Lanzini, L., Santarelli, M., Leone, P., 2013. Solid Oxide Fuel Cell energy production from biogas impact of contaminants (COS, C2H4) on fuel cell performance. ATI 2013. Papurello, D., Schuhfried, E., Lanzini, A., Romano, A., Cappellin, L., Märk, T.D., Silvestri, S., Biasioli, F., 2013. Influence of co-vapors on biogas filtration for fuel cells monitored with PTR-MS (Proton Transfer-Reaction Mass Spectrometry). Fuel Processing Technology 2014; 118: 133-140.(0378-3820/$ - http://dx.doi.org/10.1016/j.fuproc.2013.08.011) 13
Davide Papurello davide.papurello@polito.it 3402351692 DENERG, Corso Duca degli Abruzzi, 24, 10129, Turin, Italy. Thanks for the attention 14