1. Wood pellets combustion with rich and diluted air in HTAC furnace Author: Ramona DINU

2. Wood pellets combustion with rich and diluted air in HTAC furnace 2 Paper objective: Paper objective: biomass combustion behavior using high temperature air combustion by burning wood pellets into the HTAC furnace. biomass combustion behavior using high temperature air combustion by burning wood pellets into the HTAC furnace. Measured parameters: pellet’s mass reduction; pellet’s mass reduction; CO 2 and CO flue gases concentrations; CO 2 and CO flue gases concentrations; NO x emission level; NO x emission level; ignition time; ignition time; flame behavior flame behavior

3. Wood pellets combustion with rich and diluted air in HTAC furnace 3 Experimental facility (HTAC furnace): Legend: 1. methane inlet; 2. oxidation air inlet; 3. oxygen inlet; 4. nitrogen inlet; 5. burner; 6. 1 rst part of the combustion chamber; 7. ceramic honeycomb; 8. 2 nd part of the combustion chamber; 9. cooling chamber; 10. cooling nitrogen inlet; 11. pellet inlet flange; 12. glass window; 13. thermocouple (T 1 ); 14. thermocouple (T 2 ); 15. thermocouple (T 3 ); 16. facility outlet; 17. flue gas analysis probe.

4. Wood pellets combustion with rich and diluted air in HTAC furnace 4 Biomass feedstock characteristics Experiments range Temperature(°C)Oxidizer8001000 5 % -30s60s180s300s-30s60s180s300s 10 % -30s60s180s300s-30s60s180s300s 21 % -30s60s180s300s-30s60s180s300s 30 % -30s60s180s300s-30s60s180s300s 70 % -30s60s180s300s-30s60s180s300s 100 % 15s30s60s180s300s15s30s60s180s300s Physical properties: Pellet length mm 13.00 - 15.00 Diameter of the pellet mm8.00-9.00 Average pellet weight g5.00 Proximate analysis (wet basis): Ash content (550 ºC) %11.10 Volatiles content %19.41 Fixed carbon %62.79 HHV MJ/k g 28.95 LHV 27.99 Ultimate analysis (wet basis): Moisture content (105 ºC) %6.7 Carbon (C) %70.91 Hydrogen (H) %3.73 Oxygen (O) %5.78 Nitrogen (N) %1.40 Sulphur (S) %0.32 Chlorine (Cl) %0.01

5. Wood pellets combustion with rich and diluted air in HTAC furnace 5 Experimental Results: b)NO x emission level a)Mass loss

6. Wood pellets combustion with rich and diluted air in HTAC furnace 6 Experimental Results: c)CO 2 concentration level d)CO concentration level

7. Wood pellets combustion with rich and diluted air in HTAC furnace 7 Experimental Results: f)Ignition time and flame behavior 5s 10s - ignition 100s 110s 125s - char Oxidant at 1000 ºC and 5% oxygen concentration Oxidant at 1000 ºC and 100% oxygen concentration 0s - ignition 2s 7s 70s 170s - char

8. Wood pellets combustion with rich and diluted air in HTAC furnace 8 Conclusions: Pellet mass reduction depends on oxidant temperature; Pellet mass reduction depends on oxidant temperature; For lower oxidant temperature 800 ºC, the oxygen concentration has more influence over the mass loss than for the temperature of 1000 ºC; For lower oxidant temperature 800 ºC, the oxygen concentration has more influence over the mass loss than for the temperature of 1000 ºC; The level of NO X is proportional with the oxygen concentration and oxidant temperature; The level of NO X is proportional with the oxygen concentration and oxidant temperature; The levels of CO2 and CO are also dependent on oxygen concentration and temperature; The levels of CO2 and CO are also dependent on oxygen concentration and temperature; The ignition time is strongly influenced by the oxidant temperature and oxygen concentrations. The ignition time is strongly influenced by the oxidant temperature and oxygen concentrations.