Table 4 - uploaded by Francisco Antonio Rocco Lahr
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This research reports an investigation of the potential of Eucalyptus grandis and Corymbia citriodora for structural applications in civil construction with an emphasis on the wood-charring process in fire condition. Published data on wood carbonization to determine the charring rate for structural propose are sparse in Brazil as there have been on...
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Fractionated pyrolysis coupled to gas chromatography and mass spectrometry (Py-GC/MS) appears as an interesting analytical tool for elucidating lignocellulosic biomass structure, as it allows the progressive release of chemical fragments representative of biomass macromolecular composition. In this paper the effect of fractionated pyrolysis time (f...
Citations
... Pinto et al. [5] stated that the insufficiency of oxygen in wood combustion process results in the wood decomposition into several components as well as charred layer formation. ...
... Wetter wood needs more energy for reaching the flash point or autoignition temperature, i.e., the flame spread index is lower. Pinto et al. [5] stated that the insufficiency of oxygen in wood combustion process results in the wood decomposition into several components as well as charred layer formation. ...
... It is often described as a black porous solid part of the wood. Its composition is formed mostly by elemental carbon [5]. Many authors stated that it consists of several layers. ...
The aim was to investigate the relationship of charred layer parameters (also wood fire resistance) and moisture content of European larch (Larix decidua L.) wood. For this purpose, finite element model (FEM) was developed. To develop FEM, ANSYS software and transient thermal analysis were applied. To validate developed FEM, the medium-scale fire tests were provided in the laboratory chamber. In the fire tests the beams made of larch wood have undergone the thermal loading with radiant panel. The FEM validation results showed very strong correspondence of numerical and experimental results, when achieving the overall accuracy of 93.4%. Validated FEM was further used to determine the relationship between the larch beams moisture content and formation of charred layer, i.e., its parameters. The results from the simulation pointed out the fact, the wetter the wood, the higher its fire resistance. This is very important information for studying the formation of a charred layer and a layer of degraded wood. After increasing the moisture content
from 10% to 30%, the area of the charred layer decreased by approximately 20%. The area of degraded wood decreased by almost 30%, so it can be stated that the area of the charred layer of wood and
degraded wood decreases exponentially with increasing wood moisture content.
... Regarding the thermal gravimetric curves (TG and DTG) shown in Fig. 3, they can be divided into three regions, wherein: region I is related to moisture loss (from 20 ºC to 100 ºC), region II is related to degradation in hemicellulose and cellulose (from 160 ºC to 480 ºC), and region III is related to degradation of cellulose and lignin (from 450 ºC to 600 ºC), as suggested by Pinto et al. (2016). ...
... Proses pemasakan serpih bambu dan bambu dekortikasi dilakukan pada kondisi yang sama dan hasil analisis rendemen dan bilangan Kappa pulp belum putih ditunjukkan pada Gambar 3. (Kojima et al., 2014;Antes and Joutsimo, 2015;Neiva et al., 2015;Zhou et al., 2015;Gallina et al., 2016;Hou et al., 2016;Pinto et al., 2016;Poletto, 2016) 2 (Ataç and Eroǧlu, 2013;Gulsoy and Tufek, 2013;Xiang and He, 2013;Cotana et al., 2014;Herrera et al., 2014;Castillo et al., 2015;Gulsoy and Ozturk, 2015;Reyes et al., 2016;Valenzuela et al., 2016) Gambar 3. Rendemen dan Bilangan Kappa Pulp Belum Putih dari Serpih Bambu dan Bambu Dekortikasi lebih rendah dibandingkan serpih bambu, hal itu dimungkinkan karena ukuran partikel bambu dekortikasi lebih kecil sehingga penetrasi cairan kimia pemasak lebih mudah (Gambar 1). Delignifikasi oleh cairan kimia pemasak akan lebih intensif sehingga menyebabkan rendemen dan bilangan Kappa lebih rendah. ...
The need for long fiber dissolving pulp in Indonesia can only be met from imports. Bamboo is a nonwood plant and known as source of long fiber. This research aims to study the potential of spiny bamboo to be used as raw material for producing long fiber dissolving pulp. This research was conducted using two different types of raw materials preparation to produce bamboo chip and decorticated bamboo. The pulping process is carried out by pre-hydrolysis kraft and bleaching performed with two different bleaching sequences, i.e DoED1D2 and DoEpD1D2 . Based on the experimental results, spiny bamboo has good potential to be used as raw material for dissolving pulp. Spiny bamboo belongs to long fibers with an average fiber length of 2.46 mm. The dissolving quality depends on the preparation of the raw material and the bleaching sequence. The yield of spiny bamboo dissolving pulp ranged from 37.97 - 40.76% with alpha cellulose content of 94.88 - 98.67%, and viscosity of 16.43 - 25.75 cP. Decorticated bamboo with bleaching sequence of DoEpD1D2 produced the highest quality of dissolving pulp with the highest brightness and alpha cellulose were 89.61% ISO and 98.67%, respectively.
... Only processes I and II (Table 4) describe the thermal degradation of wood samples, and they confirm the theory of two-stage wood degradation (Lowden et al. 2013). Pinto et al. (2016) showed via TGA that their analyzed wood species were stable up to 250 °C. ...
Wood as a flammable material can be characterized by fire and technical parameters, such as initial temperatures of its degradation, caloric heat, caloric value, and explosion limits. These parameters reflect the suitability of using a particular type of wood for construction purposes or as biofuel. This article presents selected characteristics of beech wood (Fagus sylvatica L.) particles (dust fractions) on the basis of continual thermal loading. The thermal properties of beech particles were characterized by thermogravimetric analysis (TG), which indicated different thermal degradation patterns for different dust fractions. The beech wood dust consisted mainly of fractions of 80 μm, 32 μm, and < 32 μm, which was 70.50% of the sample. These fractions form explosive mixtures with air, and their thermal degradation involves only one step.
In the process of computer modeling the formation of a charred layer in wood materials, it is important to implement the correct material data. In thermal analysis, there exist two different approaches of implementation: the temperature-dependent material data properties, heat capacity approach and enthalpy approach, which is not commonly used but which has a few advantages. This approach should be examined in more detail because it can solve the problem associated with inaccurate results at temperatures around 100 ◦C. This scientific paper deals with the assessment of the computer-aided fire modeling and simulation suitability based on the enthalpy approach for determining the charred layer of structural elements. The structural elements selected for testing were spruce wooden beams with rectangular and circular cross-sections. A finite element model (FEM) was created in ANSYS software. The model was validated by medium-scale fire tests data of the spruce wooden beams loaded with a radiation panel. Boundary conditions were identical to the medium-
scale fire test. Due to the enthalpy approach, the temperature curves from the simulations also faithfully simulated the section with a constant temperature around 100 ◦C. Within the temperature profiles, the accuracy of simulations averaged 91.7%. The accuracy of the simulations describing the total area of the charred layer was 93.0% on average. Presented FEM can be used in the search for new construction solutions for wooden elements and modifications to the design of cross-sections of wooden beams or wooden joints so that they can better withstand fire conditions.
