Modelling of Gasification of Refuse-derived fuel (RDF) based on - PowerPoint PPT Presentation

Modelling of Gasification of Refuse-derived fuel (RDF) based on laboratory experiments Juma Haydary Department of Chemical and Biochemical Engineering Institute of Chemical and Environmental Engineering Faculty of Chemical and Food Technology Slovak University of Technology in Bratislava, Slovakia Cyprus 2016

Slovak University of Technology in Bratislava Faculty of Chemical and Food Technology Cyprus 2016

Institute of Chemical and Environmental Engineering Reactor Engineering National center for research Reaserch Group and application of renewable energy sources • Experimental study and mathematical modeling of fuel thermal processes • Pyrolysis, gasification and combustion of solid fuels • Biomass, polymer waste, MSW, and coal thermal and catalytic processing for production energy and materials Cyprus 2016

Refuse-Derived Fuel (RDF) Hazardous Inorganics Biodegradables Metals wastes Cyprus 2016

RDF composition Component Material w i [kg/kg] 0,6317 Paper White paper, recycled paper 0,1578 Foil LDPE, HDPE 0,1910 Plastics Rigid plastics, polystyrene, polyurethane 0,0194 Textile Polyamide, polyester, cotton , wool Cyprus 2016

Proximate and Elemental Composition of RDF Com. Mois. VM* FC* ASH* C H N S O** Wt. % 10 75.5 8.9 15.6 51.7 5.9 0.9 0.4 25.5 *moisture free basis **calculated to 100% Cyprus 2016

Behaviour of Thermal decomposition Cyprus 2016

Behaviour of Thermal decomposition Cyprus 2016

Heating value of RDF Heating value Component [kJ/kg] Paper 13410 Foil 43860 Plastics 33570 Textile 19770 Mixed RDF 20810 Cyprus 2016

Tar content measurement 90 80 70 Tar (mg/g RDF) 60 50 40 30 20 600 700 800 900 1000 1100 1200 Temperature (°C )

Gasification Model Global material balance of RDF gasification Assumptions: • Steady state flow is        CH O N S x O x H O x CO x CO x H x CH x H O c e 1 2 2 2 3 4 2 5 2 6 4 7 2 b d    RDF considered inside the x NH x H S x CH O N S 8 3 9 2 10 b 1 c 1 d 1 e 1 TAR gasifier Reactions: • No temperature and    C 0,5 O CO     2 C H O H CO concentration gradient 2 2       CO 0,5 O CO C CO 2 CO exist inside the reactor 2 2 2        H 0,5 O H O CH H O 3 H CO • The residence time is 2 2 2 4 2 2        enough long to reach CH 2 O CO 2 H O C 2 H CH 4 2 2 2 2 4     CO H O CO H complete decomposition 2 2 2 Equilibrium constant: of RDF and unreacted part  of RDF is only carbon.    P i         K x i i • Only the major species are a i i   0 P considered in the product   298 G ,  gases, i.e CO, CO 2 , H 2 , CH 4 298 r      K e 298 298 298 G H T S a r r r RT , H 2 O, NH 3 , H 2 S, N 2 and Tar           298 298 298 298 H H S S r i f i r i f i         298 T  H H c ( T 298)       298 S S c ln 298 r r i pi r r i pi

Enthalpy balance:        H H H Q H H H Q 2( ) RDF O air steam R gas ash C loss      Q m wQ ( H n ) IF, T air =T RDF =T ref , then =0, =0 R RDF i i c i i H H RDF O 2( air )        m wQ ( H n ) Q   RDF i i c i i loss T T    ref    nc m c m c m c i pi C pC ash pash steam steam Q – heat of reaction [ J ], m RDF – mass flow of RDF feed [kg] R H – enthalpy of RDF feed [ J ], RDF H – enthalpy of oxygen and air respectively [ J ], n i – mole flow of component i in the products [kmol] O 2( air ) H – enthalpy of water steam [ J ], steam w i – maas fraction of component i in the feed (paper, foil, plastics, textil H – enthalpy of gas [ J ], gas H – enthalpy of ash [ J ], Q i – lower heating value of component i in the feed (paper, foil, plastics, ash -1 ], textile) [Jkg H – enthalpy of unreacted carbon [ J ], C  - heat of combustion of component i in the products [Jkmol -1 ] c H Q i – heat losses from the reactor [ J ] loss m ash – mass flow of ash [kg] m ash – mass flow of remaining carbon [kg] m steam – mass flow of steam [kg] – specific heat capacity of ash [Jkg -1 K -1 ] c pash – specific heat capacity of remaining carbon [Jkg -1 K -1 ] c pC – specific heat capacity of steam [Jkg-1K -1 ] c psteam

Results of modelling RDF gasification Observed parameters: Conversion of RDF Reactor Temperature Gas composition Content of pollutants (NH3, H2S, TAR) Variables: Oxygen (air) to RDF mass ratio Steam to RDF mass ratio

Air Gasification 0,7 0,6 Mole fraction 0,5 H2 0,4 CO 0,3 CH4 0,2 CO2 0,1 N2 0 0 1 2 3 4 m(air)/m(RDF) 1500 120 Temperature (°C ) Conversion (%) 100 1000 80 60 500 40 20 0 0 0 1 2 3 4 m(air)/m(RDF) Temperature Conversion

0,1 0,0035 0,09 0,003 H2S and NH3 mole fraction 0,08 0,0025 Tar mass fraction 0,07 0,06 0,002 0,05 0,0015 0,04 0,03 0,001 0,02 0,0005 0,01 0 0 0 1 2 3 4 m(air)/m(RDF) Tar H2S NH3

Gasification of RDF Using O 2 0,7 0,6 Mole fraction 0,5 H2 0,4 CO 0,3 CH4 0,2 CO2 0,1 0 N2 0 0,2 0,4 0,6 0,8 m(O2)/m(RDF) 3000 150 Temperature (K) Conversion (%) 2000 100 1000 50 Temperature Conversion 0 0 0 0,2 0,4 0,6 0,8 m(O2)/m(RDF)

Effect of RDF composition 3000 150 Com. Wt. % Temperature (K) Conversion (%) Mois 10 2000 100 VM 75.5 FC 8.9 ASH 15.6 1000 50 C 51.7 H 5.9 0 0 N 0.9 0 0,2 0,4 0,6 0,8 S 0.4 O 25.5 m(O2)/m(RDF) Temperature Conversion Sensitivity Results Curve 3000 0,500 0,55 0,27 0,50 100 20,0 19,5 0,26 0,475 95 2800 19,0 0,50 0,45 0,25 18,5 0,450 90 2600 18,0 0,24 Com. Wt. % 0,45 0,40 17,5 0,425 85 0,23 Mois 1.2 2400 17,0 0,40 16,5 0,22 0,35 0,400 80 VM 80.22 TR K 2200 16,0 0,21 XH2 0,35 15,5 FC 5.23 0,375 75 XCO 0,30 0,20 2000 15,0 XCO2 ASH 13.34 0,30 XCH4 0,350 70 14,5 0,19 XC O2 XC H4 CO N TR K XH 2 XC O CON HC 1800 0,25 14,0 C 51.66 HC 0,18 0,325 65 13,5 0,25 H 8.82 1600 13,0 0,17 0,20 0,300 60 12,5 0,20 0,16 N 0.66 1400 12,0 0,275 55 0,15 0,15 11,5 S 0.08 0,15 1200 11,0 0,14 0,250 50 O 25.42 10,5 0,10 0,10 0,13 1000 10,0 0,225 45 9,5 0,12 0,05 0,05 800 9,0 0,200 40 0,11 8,5 600 0,175 0,00 0,10 0,00 35 8,0 0,20 0,25 0,30 0,35 0,40 0,45 0,50 0,55 0,60 0,65 0,70 0,75 0,80 0,85 0,90 0,95 1,00 1,05 1,10 1,15 1,20 1,25 R

Effect of Steam in RDF Gasification 0,5 Mole fraction 0,4 0,3 H2 0,2 CO 0,1 CO2 0 0 0,1 0,2 0,3 0,4 0,5 m(Steam)/m(RDF) 1200 10 Heating Value Temperature (K) 1150 9,5 (MJ/kg) 1100 9 1050 8,5 1000 8 0 0,1 0,2 0,3 0,4 0,5 m(Steam)/m(RDF) Temperature Heating value

Conclusion • For RDF studied in this work,100% of RDF conversion in gasification by air was reached at m air /m RDF =2,2. However, the gas heating value was 4,4 MJ/Nm 3 • Gasification of RDF using Oxygen enables production of a gas with heating value around 10 MJ/Nm 3 at m O2 /m RDF =0,45 • Elemental Composition of RDF has a crutial effect on riquired m air /m RDF • Raw untreated gas tar content was 3.3 mass %; tar fraction content a solid phase insoluble in isopropanol • By increasing the m steam /m RDF the content of H2 and CO 2 increased, However, the content of CO, reactor temperature and gas heating vale decreased October 2015

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