Characteristics of oil shale pyrolysis in a two-stage fluidized bed

Rapid pyrolysis of oil shale coupled with in-situ upgrading of pyrolysis volatiles over oil shale char was studied in a laboratory two-stage fluidized bed(TSFB) to clarify the shale oil yield and quality and their variations with operating conditions. Rapid pyrolysis of oil shale in fluidized bed(FB) obtained shale oil yield higher than the Fischer Assay oil yield at temperatures of 500-600 ℃. The highest yield was 12.7 wt% at 500 ℃ and was about1.3 times of the Fischer Assay oil yield. The heavy fraction(boiling point 350 ℃) in shale oil at all temperatures from rapid pyrolysis was above 50%. Adding an upper FB of secondary cracking over oil shale char caused the loss of shale oil but improved its quality. Heavy fraction yield decreased significantly and almost disappeared at temperatures above 550 ℃, while the corresponding light fraction(boiling point 350 ℃) yield dramatically increased. In terms of achieving high light fraction yield, the optimal pyrolysis and also secondary cracking temperatures in TSFB were 600 ℃, at which the shale oil yield decreased by 17.74% but its light fraction yield of 7.07 wt% increased by 86.11% in comparison with FB pyrolysis. The light fraction yield was higher than that of Fischer Assay at all cases in TSFB. Thus, a rapid pyrolysis of oil shale combined with volatile upgrading was important for producing high-quality shale oil with high yield as well.     

Synthesis and pyrolysis behavior of a soluble polymer precursor for ultra-fine zirconium carbide powders

A soluble polymer precursor for ultra-fine zirconium carbide (ZrC) was successfully synthesized using phenol and zirconium tetrachloride as carbon and zirconium sources, respectively. The pyrolysis behavior and structural evolution of the precursor were studied by Fourier transform infrared spectra (FTIR), differential scanning calorimetry, and thermal gravimetric analysis (DSC–TG). The microstructure and composition of the pyrolysis products were characterized by X-ray diffraction (XRD), laser Raman spectroscopy, scanning electron microscope (SEM) and element analysis. The results indicate that the obtained precursor for the ultra-fine ZrC could be a Zr–O–C chain polymer with phenol and acetylacetone as ligands. The pyrolysis products of the precursor mainly consist of intimately mixed amorphous carbon and tetragonal ZrO₂ (t-ZrO₂) in the temperature range of 300–1200 °C. When the pyrolysis temperature rises up to 1300 °C, the precursor starts to transform gradually into ZrC, accompanied by the formation of monoclinic ZrO₂ (m-ZrO₂). The carbothermal reduction reaction between ZrO₂ and carbon has been substantially completed at a relatively low temperature (1500 °C). The obtained ultra-fine ZrC powders exhibit as well-distributed near-spherical grains with sizes ranging from 50 to 100 nm. The amount of oxygen in the ZrC powders could be further reduced by increasing the pyrolysis temperature from 1500 to 1600 °C but unfortunately the obvious agglomeration of the ZrC grains will be induced.     

Additive and pyrolysis atmosphere effects on polysiloxane-derived porous SiOC ceramics

Porous silicon oxycarbide (SiOC) is emerging as a much superior ultrahigh surface area material that can be stable up to high temperatures with great tailorability through composition and additive modifications. In this study, bulk SiOCs were fabricated from a base polysiloxane (PSO) system by using different organic additives and pyrolysis atmospheres followed by hydrofluoric acid (HF) etching. The additives modify the microstructural evolution by influencing the SiO₂ nanodomain formation. The SiOC ceramics contain significantly less SiC and more SiO₂ with Ar + H₂O atmosphere pyrolysis compared to Ar atmosphere pyrolysis. Water vapor injection during pyrolysis also causes a drastic increase in specific surface areas. The addition of 10 wt% tetraethyl orthosilicate (TEOS) with Ar + H₂O pyrolysis produces a specific surface area of 1953.94 m²/g, compared to 880.09 m²/g for the base PSO pyrolyzed in Ar. The fundamental processes for the composition and phase evolutions are discussed as a novel pathway to creating ultrahigh surface area materials. The ability to drastically increase the specific surface area through the use of pyrolysis atmosphere and organic additives presents a promising processing route for highly porous SiOC ceramics.     

Fabrication of porous Al2O3-based ceramics using ball-shaped powders by preceramic polymer process in N2 atmosphere

Porous Al₂O₃-based ceramics were successfully fabricated using ball-shaped powders by preceramic polymer process in N₂ atmosphere. These results showed that the amorphous Si-O-C ceramics were formed on the surface of ball-shaped Al₂O₃ particles by the pyrolysis of the silicone resin during sintering in N₂ atmosphere, which played a role in connecting the Al₂O₃ particles by forming the sintering necks. When the sintering temperatures increased from 1100 °C to 1600 °C, the formed Si-O-C ceramics still existed in the amorphous state and had no crystallization. Interestingly, the amorphous β-SiC formed at 1300 °C and its amount gradually increased with further increasing temperatures. The linear shrinkage rate of the samples varied from 0.49% to 0.73% and the weight loss rate increased from 2.01% to 10.77%. The apparent porosity remarkably varied with the range of 24.9% and 34.5%, as the bulk-density varied from 2.66 to 2.47 g/cm³. The bending strength gradually increased from 9.36 to 22.51 MPa with increasing temperatures from 1100 °C to 1500 °C, however, the bending strength remarkably decreased at 1600 °C, which was attributed to the comprehensive function of the high porosity, broken Al₂O₃ particles and weak connection between Al₂O₃ particles in the samples.     

Coke formation and reaction pathways of catalyst-surface-generated radicals during the pyrolysis of ethane using Ni mesh catalyst

The use of a conventional porous catalyst in the study of the pyrolysis of ethane (or any hydrocarbon) is complicated because reactions take place both on the catalyst surface and in the gas phase (including pores). A non-porous nickel mesh catalyst was used to study the catalytic pyrolysis of C₂H₆ in a quartz tubular reactor at 750 °C. Our experimental results strongly indicate that the radicals formed on the catalyst surface could easily desorb from the catalyst surface when the gas film around the mesh wires was thinned by increasing the gas flow rate passing through the mesh. The desorption of radicals from the catalyst surface greatly limited the formation of coke on the catalyst surface, leading to sustained high catalytic activities even in pure C₂H₆ at 750 °C. The catalyst could have dual roles. It could act as a chain reaction terminator by providing a surface for the chain termination reactions to take place. The mesh catalyst could also act as a chain reaction re-initiator by providing additional radicals into the gas phase in which the desorbed radicals re-initiate and participate in the chain reactions. The dual roles of the mesh catalyst were largely responsible for the changes in net product formation rates and product distribution (e.g. the C₂H₄/CH₄ ratio).     

The volatilization behavior of chlorine in coal during its pyrolysis and CO2-gasification in a fluidized bed reactor

The volatilization behavior of chlorine in three Chinese bituminous coals during pyrolysis and CO₂-gasification in a fluidized bed reactor was investigated. The modes of occurrence of chlorine in raw coals and their char samples were determined using sequential chemical extraction method. The Cl volatility increases with increasing temperature. Below 600 °C the Cl volatility is different, depending on the coal type and the occurrence mode of Cl. Above 700 °C, the Cl volatilities for the three coals tested are all higher than 80%. About 41% of the chlorine in Lu-an coal and 73% of that in Yanzhou coal are organic forms, and most of them are covalently-bonded organic chlorine, which shows high volatile behavior even at low pyrolysis temperatures (below 500 °C), while the inorganic forms of chlorine in two coal samples are hardly volatilized even at low pyrolysis temperatures (below 400 °C). The restraining efficiency of addition of CaO on chlorine volatility is greatly dependent on pyrolysis temperature. The optimal restraining efficiency can be obtained at temperature range from 450 to 650 °C during pyrolysis of Lu-an coal. The volatile behavior of Cl is mainly dependent on temperature. Above 700 °C high volatility of Cl is obtained in both N₂ and CO₂ atmospheres.     

Carbon molecular sieve dense film membranes derived from Matrimid® for ethylene/ethane separation

Development of dense film carbon molecular sieve (CMS) membranes for ethylene/ethane (C₂H₄/C₂H₆) separation is reported. A commercial polyimide, Matrimid®, was pyrolyzed under vacuum and inert argon atmosphere, and the resultant CMS films were characterized using pure C₂H₄ and C₂H₆ permeation at 35 °C, 50 psia feed pressure. The effects on C₂H₄/C₂H₆ separation caused by different final vacuum pyrolysis temperatures from 500 to 800 °C are reported. For all pyrolysis temperatures separation surpassed the estimated ‘upper bound’ solution processable polymer line for C₂H₄ permeability vs. C₂H₄/C₂H₆ selectivity. C₂H₄ permeability decreased and selectivity increased with increasing pyrolysis temperature until 650–675 °C where an optimum combination of C₂H₄ permeability ～14–15 Barrer with C₂H₄/C₂H₆ selectivity ～12 was observed. A modified heating rate protocol for 675 °C showed further increase in permeability with no selectivity loss. CMS films produced from argon pyrolysis showed results comparable to vacuum pyrolysis. Further, mixed gas (63.2 mol% C₂H₄ + 36.8 mol% C₂H₆) permeation showed a slightly lower C₂H₄ permeability with C₂H₄/C₂H₆ selectivity increase rather than a decrease that is often seen with polymers. The high selectivity of these membranes was shown to arise from a high ‘entropic selection’ indicating that the ‘slimmer’ ethylene molecule has significant advantage over ethane in passing through the rigid ‘slit-shaped’ CMS pore structure.     

CFB air-blown flash pyrolysis. Part II: Operation and experimental results

The main operational characteristics of a novel gasifier operating in the CFB mode are outlined in this paper, based on the experimental results from a total of 11 runs in the pyrolysis mode. The operation runs constituted the main experiments in the CFB reactor, carried out to derive meaningful mass balance and additional operational data for the CFB pyrolyzer. The experiments were conducted in varying operating conditions determined by the most important parameters, i.e., biomass flowrate, fluidizing gas flowrate, air factor, initial bed inventory), temperature in the CFB riser, vapor residence time and nominal air factor – or equivalence ratio, S_b.The results obtained showed that the reactor configuration successfully operated as a biomass fast pyrolysis system to maximize liquid yields reaching 61.50 wt% on a maf biomass basis, with the novel feature of providing for autothermal operation at 500 °C and with 0.46 s gas–vapor residence time, by utilizing the by-product char energy content in a single reactor. The reactor provides a very high specific throughput of 1.12–1.48 kg/h m² and the lowest gas-to-feed ratio of 1.3–1.9 kg gas/kg feed compared to other fast pyrolysis processes based on pneumatic reactors and has a good scale-up potential, providing significant capital cost reduction. Results to date suggest that the process is limited by the extent of char combustion. Future work should address resizing of the char combustor to increase overall system capacity, improve the solid separation and substantially increase liquid recovery.     

Effects of thermal pretreatment in helium on the pyrolysis behaviour of Loy Yang brown coal

A wire-mesh reactor capable of multi-step heating/holding and minimising secondary reactions of volatiles was used to investigate the effects of thermal pretreatment in inert gas on the subsequent rapid pyrolysis behaviour of Loy Yang brown coal. Our results indicate that the presence of small amounts (<10 wt%) of moisture in brown coal has little influence on the tar and char yields from the pyrolysis of brown coal at 1000 K s⁻¹. While the hydrogen bonds between the moisture and the O-containing functional groups in the brown coal have little effects on its pyrolysis behaviour, the hydrogen bonds among the O-containing functional groups tend to induce cross-linking reactions to reduce the tar yields. Preheating the brown coal at >250 °C leads to reduced tar and increased char yields. However, the characterisation of tars using UV-fluorescence spectroscopy indicates that significant decreases in the release of larger aromatic ring systems are only observed after preheating at >380 °C for 30 min. The presence of ion-exchangeable cations (e.g. Ca²⁺) in the brown coal tends to stabilise the carboxylate groups and only preheating at >350 °C would result in changes in pyrolysis yields during the subsequent pyrolysis at 1000 K s⁻¹. These results may be explained by considering the formation of cross-links involving peripheral groups at low preheating temperatures and the formation of cross-links involving aromatic ring systems at elevated temperatures.     

Characteristics of hemicellulose,cellulose and lignin pyrolysis

The pyrolysis characteristics of three main components (hemicellulose, cellulose and lignin) of biomass were investigated using, respectively, a thermogravimetric analyzer (TGA) with differential scanning calorimetry (DSC) detector and a pack bed. The releasing of main gas products from biomass pyrolysis in TGA was on-line measured using Fourier transform infrared (FTIR) spectroscopy. In thermal analysis, the pyrolysis of hemicellulose and cellulose occurred quickly, with the weight loss of hemicellulose mainly happened at 220–315 °C and that of cellulose at 315–400 °C. However, lignin was more difficult to decompose, as its weight loss happened in a wide temperature range (from 160 to 900 °C) and the generated solid residue was very high (∼40 wt.%). From the viewpoint of energy consumption in the course of pyrolysis, cellulose behaved differently from hemicellulose and lignin; the pyrolysis of the former was endothermic while that of the latter was exothermic. The main gas products from pyrolyzing the three components were similar, including CO₂, CO, CH₄ and some organics. The releasing behaviors of H₂ and the total gas yield were measured using Micro-GC when pyrolyzing the three components in a packed bed. It was observed that hemicellulose had higher CO₂ yield, cellulose generated higher CO yield, and lignin owned higher H₂ and CH₄ yield. A better understanding to the gas products releasing from biomass pyrolysis could be achieved based on this in-depth investigation on three main biomass components.     

Synthesis and pyrolysis evolution of glucose-derived hydrothermal precursor for nanosized zirconium carbide

Nanosized zirconium carbide (ZrC) was synthesized successfully by a novel hydrothermal precursor conversion method using chelation of polydentate glucose as the carbon source. During the pyrolysis, the core-matrix structure of intimate nanosized ZrO₂ and amorphous carbon mixture forms, resulting in short diffusion path and limit of grain growth. ZrC first appears at a much lower temperature of 1200 °C and completes conversion at 1400 °C in comparison with that of precursor without hydrothermal treatment. By raising the heating temperature to 1600 °C, oxygen content could be reduced (0.55 wt%) with a low residual carbon content (2.3 wt%), and the average size of the spherical crystallite increases from 100 nm to 200 nm. Based on above ZrC powders, the additive-free ceramic with 99.4% relative density by spark plasma sintering (SPS) at a low temperature of 1700 °C has been achieved.     

Effects of oxidation curing and sintering temperature on the microstructure formation and heat transfer performance of freestanding polymer-derived SiC films for high-power LEDs

Effects of oxidation cross-linking and sintering temperature on the microstructure evolution, thermal conductivity and electrical resistivity of continuous freestanding polymer-derived SiC films were investigated. The as-received films consisting of β-SiC nanocrystals embedded in amorphous SiO_xC_y and free carbon nanosheets were fabricated via melt spinning of polycarbosilane (PCS) precursors and cured for 3 h/10 h followed by pyrolysis from 900 °C to 1200 °C. Results reveal that nanoscale structure (β-SiC/SiO_xC_y/C_free) provides an ingenious strategy for constructing highly thermal conductive, highly insulating and highly flexible complexes. In particular, the 3 h-cured films sintered at 1200 °C with satisfying thermal conductivity (46.8 W m^?1 K^?1) and electrical resistivity (2.1 × 10⁸ Ω m) are suitable for the realization of high-performance substrates. A remarkable synergistic effect (lattice vibration of β-SiC nanocrystals and close-packed SiO_xC_y, free-electron heat conduction of β-SiC and free carbon, and supporting role of oxygen vacancy) contributing to thermal conductivity improvement is proposed based on the analysis of microstructure, intrinsic properties and simulations. Eventually, the SiC films without additional dielectric layers are directly silk-screen printed with high-temperature silver paste and used as heat dissipation substrates for high-power LED devices via chip-on-board (COB) package. The final devices can emit bright light with low-junction temperature (52.6 °C) and good flexibility owing to the mono-layer SiC substrate with low thermal resistance and desirable mechanical properties. This work offers an effective approach to design and fabricate flexible heat dissipation ceramic substrates for thermal management in advanced electronic packaging fields.     

Microwave dielectric properties of YAG ceramics prepared by sintering pyrolysised nano-sized powders

YAG ceramics with good dielectric properties were prepared via a modified pyrolysis method, with yttrium nitrate as the yttrium source and combined aluminium sulphate and aluminium nitrate as aluminium sources, and subsequent sintering in a muffle furnace. The effects of the different aluminium sources on the powder characteristic and the impact of sintering temperature, sintering aids (TEOS) and additive (TiO₂) on the dielectric properties of the ceramics were studied. The results show that well-dispersed pure YAG nano-powders can be obtained after calcination at 1000 °C with an aluminium sulphate and aluminium nitrate molar ratio of 1.5:2. The relative density, permittivity (ε_r) and quality factor (Q×f) of the YAG ceramics increase with sintering temperature and TEOS addition. TiO₂ can greatly promote τ_f to near-zero but decreases Q×f. The relative density, ε_r, Q×f and τ_f of the YAG–1 wt% TEOS–1 wt% TiO₂ ceramic obtained at 1520 °C are 97.6%, 9.9, 71, 738 GHz and −30 ppm/°C, respectively.     

Fabrication of carbon fiber reinforced ceramic matrix composites with improved oxidation resistance using boron as active filler

Boron was introduced into C_f/SiC composites as active filler to shorten the processing time of PIP process and improve the oxidation resistance of composites. When heat-treated at 1800 °C in N₂ for 1 h, the density of composites with boron (C_f/SiC-BN) increased from 1.71 to 1.78 g/cm³, while that of composites without boron (C_f/SiC) decreased from 1.92 to 1.77 g/cm³. So when boron was used, two cycles of polymer impregnation and pyrolysis (PIP) could be reduced. Meanwhile, the oxidation resistance of composites was greatly improved with the incorporation of boron-bearing species. Most carbon fiber reinforcements in C_f/SiC composite were burnt off when they were oxidized at 800 °C for 10 h. By contrast, only a small amount of carbon fibers in C_f/SiC-BN composite were burnt off. Weight losses for C_f/SiC composite and C_f/SiC-BN composite were about 36 and 16 wt%, respectively.     

Modeling and optimization of industrial Fischer–Tropsch synthesis with the slurry bubble column reactor and iron-based catalyst

To optimize industrial Fischer–Tropsch(FT) synthesis with the slurry bubble column reactor(SBCR) and ironbased catalyst, a comprehensive process model for FT synthesis that includes a detailed SBCR model, gas liquid separation model, simplified CO_2 removal model and tail gas cycle model was developed. An effective iteration algorithm was proposed to solve this process model, and the model was validated by industrial demonstration experiments data(SBCR with 5.8 m diameter and 30 m height), with a maximum relative error b 10% for predicting the SBCR performances. Subsequently, the proposed model was adopted to optimize the industrial SBCR performances simultaneously considering process and reactor parameters variations. The results show that C_(5+) yield increases as catalyst loading increases within 10–70 ton and syngas H_2/CO value decreases within1.3–1.6, but it doesn't increase obviously when the catalyst loading exceeds 45 ton(about 15 wt% concentration).Higher catalyst loading will result in higher difficulty for wax/catalyst separation and higher catalyst cost. Therefore, the catalyst loading(45 ton) is recommended for the industrial demonstration SBCR operation at syngas H_2/CO = 1.3, and the C_(5+) yield is about 402 ton" per day, which has an about 16% increase than the industrial demonstration run result.     

Catalytic graphitization of novolac resin for refractory applications

This study investigated how to induce graphite generation from the carbonization process of novolac resins using conditions that can be adopted for carbon-containing refractories (CCRs) production. The effect of boron oxide or boric acid (graphitizing agents), cross-linking additive (hexamethylenetetramine) and some processing parameters (mixing technique, vacuum degassing, heating rate and thermal treatments) on carbon graphitization from a commercial novolac resin were evaluated. The X-ray diffraction (XRD) technique was selected to measure the graphitization level and crystal parameters of the prepared samples. Based on the attained results, adding graphitizing agents prior to the pyrolysis of resin resulted in carbon crystallization. The best graphitization level was obtained when the mixtures containing 6 wt% B₂O₃ or 10 wt% H₃BO₃ were fired up to 1000 °C for 5 h using a heating rate of 3 °C/min. Although the reproducibility of the obtained results was ascertained, heterogeneous graphitization could be observed based on the XRD profiles, as well as some discrepancies in the calculated graphitization level values. This phenomenon was attributed to the additives susceptibility to agglomeration, preferential graphitization starting from lower binding energy sites and heat treatment temperature, among others.     

Silicon oxycarbide-based composites produced from pyrolysis of polysiloxanes with active Ti filler

Phenyl (PPS) and methyl (PMS) containing polysiloxanes were pyrolyzed at elevated temperatures (900–1500 °C) under argon atmosphere to investigate the phase developments within the polymers. It was found that pyrolysis of the polymers under inert atmosphere up to 1300 °C leads to amorphous silicon oxycarbide (SiO_xC_y) ceramics. Conversions at higher temperatures results in the transformations into the crystalline β-SiC phases. Ceramic matrix composites (CMCs) were developed based on the active filler controlled pyrolysis (AFCOP) of polysiloxanes with active Ti filler additions. CMC monoliths were prepared with 60–80 wt.% of active Ti particulates blended into polymer precursors. Green bodies of the composites were made by warm pressing under 15 MPa pressure and ceramics were obtained by pyrolysis at elevated temperatures between 900 and 1500 °C under argon atmosphere. The results showed that due to the incorporation of active Ti fillers, formation of crystalline phases such as TiC, TiSi, and TiO occured within the amorphous matrix due to the reactions between the Ti and the polymer decomposition products. The microstructural and mechanical characterization results of the composites are presented within the paper.     

Liquid flame spray fabrication of WO3-reduced graphene oxide nanocomposites for enhanced O3-sensing performances

WO₃ is one of the inspiring sensing materials that show high response to O₃; an efficient fabrication of WO₃ film with incorporation of complementary additives is essential for enhanced sensitivity. Here we report film deposition by liquid flame spraying, characterization of nanostructured WO₃-reduced graphene oxide (rGO) composites and their gas-sensing activities to O₃. The starting feedstock was prepared from WC_l6 and rGO for pyrolysis synthesis by flame spraying. Nano-porous WO₃-rGO films were successfully fabricated and characterized by transmission electron microscopy, field emission scanning electron microscopy, Raman spectrometry, thermal analyses and X-ray diffraction. Nanosized WO₃ grains exhibited oriented nucleation on rGO flakes whereas rGO retained intact its nano-structural features after spraying. Constrained grain growth of WO₃ of 60–70 nm in size was realized in the rGO-containing films with as compared to ~220 nm in the pure WO₃ film. The WO₃-rGO film sensors showed quicker response to O₃ and faster recovery than rGO-free WO₃ film sensors. Addition of rGO in 1.0 wt% or 3.0 wt% in the films caused a significantly reduced effective working temperature of the film sensors from ~ 250 °C to ~ 150 °C.     

Pb(Zr0.95Ti0.05)O3 powders and porous ceramics prepared by one-step pyrolysis process using non-aqueous Pechini method

Using non-aqueous Pechini method, Pb(Zr_0.95Ti_0.05)O₃ powders were prepared at low temperature by one-step pyrolysis process. The polymeric gels and powders were characterized using a range of techniques, such as DTG, XRD, SEM, Raman spectroscopy, and laser particle size distribution. The perovskite phase was formed at about 350–400 °C and some oxocarbonate impurities can be detected in all samples after calcining at 400–850 °C by one-step pyrolysis process. Phase pure and porous Pb(Zr_0.95Ti_0.05)O₃ ceramics were obtained without pore formers from the powders by one-step pyrolysis process at 500 °C for 4 h. The relative densities were 87%, 91% and 94% for the ceramics sintered at 1100, 1150 and 1200 °C for 2 h, respectively. The porous ceramics sintered at 1200 °C for 2 h have homogeneously dispersed pores and fine-grain structures with an individual grain size of 0.7–2 μm.     

Effect of pyrolysis temperature on the pore structure evolution of polysiloxane-derived ceramics

Homogeneous silicon oxycarbide (SiOC) ceramic powders were prepared by pyrolysis of cross-linked polysiloxane at different temperatures (1250–1500 °C) under vacuum. The effect of pyrolysis temperature on the pore structure evolution was investigated by means of N₂ adsorption, SEM, XRD, IR and element analysis (EA). Studies showed that predominate mesoporous ceramics with the average pore size in the range of 2–13 nm were obtained after pyrolysis in this temperature range. The pore structure transformation is strongly correlated with the thermolytic decomposition process of the used precursor, such as phase separation and carbothermal reduction. At relatively lower temperature (1250–1350 °C), the ceramics had a relative small specific surface areas (35 m²/g) owing to the low degree of carbothermal reduction. However, as the carbothermal degree had an obvious augment at relative higher temperature (1400–1450 °C), the specific surface areas and total pore volume increased and reached to the maximum of 66 m²/g and 0.214 cm³/g, respectively, and subsequently decreased rapidly after 1500 °C for the reason of partial sintering of the nano-sized SiC derived from polysiloxane.