scholarly journals The Evaluation of Torrefied Wood Using a Cone Calorimeter

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1748
Author(s):  
Peter Rantuch ◽  
Jozef Martinka ◽  
Aleš Ház

This study focuses on the energy potential and combustion process of torrefied wood. Samples were prepared through the torrefaction of five types of wood: Ash, beech, oak, pine and spruce. These were heated for 2 h at a temperature of 300 °C under a nitrogen atmosphere. Torrefied wood was prepared from wood samples with dimensions of 100 × 100 × 20 mm3. These dimensions have enabled investigation of torrefied wood combustion in compact form. The effect of the external heat flux on the combustion of the samples was measured using a cone calorimeter. The observed parameters, include initiation times, heat release rate and combustion efficiency. The results show that increasing the external heat flux decreases the evenness of combustion of torrefied wood. At the same time, it increases the combustion efficiency, which reached an average value of approximately 72% at 20 kW m−2, 81% at 30 kW m−2 and 90% at 40 kW m−2. The calculated values of critical heat flux of the individual samples ranged from 4.67 kW m−2 to 15.2 kW m−2, the thermal response parameter ranged from 134 kW s0.5 m−2 to 297 kW s0.5 m−2 and calculated ignition temperature ranged from 277 °C to 452 °C. Obtained results are useful both for energy production field and for fire safety risk assessment of stored torrefied wood.

2018 ◽  
Vol 37 (1) ◽  
pp. 3-17 ◽  
Author(s):  
Peter Rantuch ◽  
Lenka Blinová ◽  
Alica Bartošová ◽  
Jozef Martinka ◽  
Igor Wachter

This article deals with the combustion process of biodiesel produced from waste vegetable oil. The main fire-technical properties related to its thermal degradation during pool fire were observed. As a test device, a cone calorimeter with modified specimen holder was used. The measurements were obtained by applying an external heat flux of 20 and 25 kW m−2 and using a spark initiator. On the basis of the measured results, the biodiesel combustion was divided into six consecutive phases described by the heat release rate, CO production, CO2 production and smoke production rate. Mean heat release rate and maximum average heat release energy peaked at 315 kW m−2, respectively at 391 kW m−2 (external heat flux of 20 kW m−2) and at 420 kW m−2, respectively at 504 kW m−2 (external heat flux of 25 kW m−2). The flash point of biodiesel reached a lower value compared to oils. The CO/CO2 ratio in the flue gas showed virtually the same combustion efficiency throughout the whole experiment.


2021 ◽  
Vol 11 (13) ◽  
pp. 5942
Author(s):  
Sun-Yeo Mun ◽  
Jae-Ho Cho ◽  
Cheol-Hong Hwang

The effects of changes in irradiance level (external heat flux), exhaust flow rate, and hood height on CO and soot yield were examined using a cone calorimeter. Black acrylic, having similar constituents as polymethyl methacrylate, was used as a combustible, and external heat fluxes ranging from 15 to 65 kW/m2 were considered. Both auto and spark ignitions were applied as ignition methods. The difference in auto and spark ignition methods had no effect on CO and soot yields, or on the mass loss rate (MLR), heat release rate (HRR), and effective heat of combustion (EHC), which are global parameters of fire. As the external heat flux increased, the mean MLR and HRR linearly increased while the EHC remained constant. When the external heat flux increased, the mean mass flow rates of CO and CO2 had a directly proportional relationship with the mean MLR. Consequently, CO and CO2 yields remained constant regardless of the external heat flux. In contrast, the mean mass flow rate and mean MLR of soot were linearly proportional as opposed to directly proportional, and the soot yield thus increased linearly with external heat flux. Variations in the exhaust flow rate and hood height, which can alter the velocity and temperature fields in post-flame and plume regions, had almost no impact on CO and soot yields, as well as on MLR and HRR. The results of this study are expected to provide improved insight into conventional approaches on the recognition of CO and soot yields as unique properties of each combustible.


2013 ◽  
Vol 390 ◽  
pp. 708-713
Author(s):  
Yu Wei Sun ◽  
Xiao Ning Yang

The thermal vacuum environment simulation test is indispensible for the development of spacecrafts. And the simulation of the external heat flux exerted onto the spacecraft is one of the determining elements of the simulation test. In China, the infra-red simulation is a common method that used as simulation equipment of the external heat flux. The planar infra-red arrays is the most typical structure elements for planar spacecraft surface, but the margin effect of infra-red arrays influences the flux uniformity on heated surface severely. Based on Monte Carlo theory, some optimizing design guidelines had been drawn about planar infra-red arrays in past investigation. This paper introduces some testing and experiment that could confirm these guidelines, and these guidelines had been applied in some vacuum thermal tests of spacecrafts successfully.


2017 ◽  
Vol 131 (2) ◽  
pp. 1463-1470 ◽  
Author(s):  
Xuelin Zhang ◽  
Teng Zhang ◽  
Changhai Li ◽  
Hongshuang Wang ◽  
Xiao Chen ◽  
...  

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