| OCR Text |
Show 2.1.18 EXPERIMENTAL TECHNIQUES The apparatus used was a termobalance reactor constructed for the combustion and pyrolysis study of powderized fuel and chips up to 30 mm by diameter. The temperature programming* allows both isothermal and dynamic (constant temperature rate) experiments within the power limits of the heating coil (3 kW). The temperature of the gas flow is programmed by on/off principle. The maximum deflect between the measured and the programmed temperatures is ±0.3 K (Pt/Pt10%Rh-thermocouples). The main components of the apparatus are shown in Fig.4. 1. vent 2. pressure regulator 3. dryer 4. flow meter 5. gas mixer 6. thermocouple Pt 10 % Rh/Pt /. 8. sample 9. gas sanpling tube 10. pump 11. 3-way stopcock 12. filter 13. gas catching bottle 14. balance Sartorius 12651^ + converter 15. computer HP 9845 16. HP-IP-way 17. data-logger HP 3497 18. QN-OFF regulator 19. power regulator 20. regulator unit 21. heating element ~h^) ® ® ® ® (? _KZZrCIHIH> Fig. 4 . The main components of the thermobalance reactor. For the dynamic experiments (5 K/min,Fig.1) the sample was milled to particle size < 0.5 mm. The weight of the sample was 1 g. The flat sample cup made of acid resistant steel was 30 mm by diameter, For the isothermal experiments with wood particles (willow,Salix Alba) a small hole was bored through the chip. The chip was hung from a hook made of acid resistance steel by using a thin Pt-wire (0.1 mm). In the experiments the reactor was heated by a gas flow (873 K), after which (within 2 seconds) the top of the furnace was rapidly lifted, the chip was hung, and the top lifted down around the sample. The accuracy of the balance above the furnace was 0.001 g. |
