Conventional pyrolysis of beech wood has been carried out for heating temperatures in the range 600−900 K, reproducing conditions interest countercurrent fixed-bed gasification. The yields liquids (water and tars) increase with temperature from about 40 to 55% dry mass, confirming results previously obtained a laboratory-scale gasifier. Apart qualitative identification ∼90 species, GC/MS techniques have applied quantify 40−43% tars (40 major contributions acetic acid, hydroxypropanone,...

Weight loss curves of thin layers (150 μm) beech wood powder, measured for heating rates 1000 K/min and final temperatures in the range 573−708 K, show char yields 37−11%. The process is kinetically controlled and, most part, isothermal. A one-step global reaction, with E = 141.2 ± 15.8 kJ/mol ln 22.2 2.9 s-1, a degradation mechanism capable capturing main features process. thermogravimetric also allow formation rate constants to be estimated total volatiles (activation energies 111.7 14.3...

Motivated by the production of compounds good industrial value, pyrolysis fir wood catalyzed alkaline (NaOH, KOH, Na2CO3, K2CO3, KC2H3O2, and NaCl) has been investigated. Catalysts have impregnated in (preliminarily extracted with water) means aqueous solutions resulting concentrations K or Na ion about 0.37−0.41%. Pyrolysis experiments done a fixed-bed reactor preheated at 800 K.The decomposition process is anticipated lower temperatures conversion times from 2.5 (NaOH) to 1.7 (NaCl)...

Packed-bed pyrolysis (heating temperature 800 K) is studied of beech and fir wood, several agro-industrial residues (corn cobs stalks, olive husks, wheat straw, hazelnut almond shells, orange peels, grape residues, artichoke stems, brewer's spent grain, pruning cuts from cherry, olive, vine, poplar trees) cellulose, aimed at determining the potentially most promising feedstock for production furfural. Parameters associated with conversion dynamics are mainly affected by packed-bed density...

The pyrolytic behavior of a cylindrical packed bed beech wood pellets, uniformly heated along the lateral surface, is studied. As heating conditions are varied, trends shown by mass loss rate and yields lumped product classes in agreement with previous literature. Moreover, detailed measurements thermal field permit, for first time, observation at central core bed, sequential (a) exothermic, (b) endothermic, (c) exothermic effects. examination corresponding temperature ranges indicates that...

The thermal decomposition of a cylindrical fixed bed consisting agricultural residues (hazelnut shells, olive pomace, straw pellets) or softwood pellets, uniformly heated along the lateral surface, is investigated for heating temperatures in range 473–800 K, and comparison made with results previously obtained beech wood pellets. Although dependent on external conditions, exothermic reaction heat effects are evident all biomasses, giving rise to maximum temperature overshoots 225 K shells),...

Thermogravimetric curves in air of wood chars obtained from different species and conventional or fast pyrolysis show a low-temperature shoulder (devolatilization) followed by high-temperature peak (combustion). A n-order global reaction provides very poor description the differential and, agreement with previous literature, requires relatively low activation energies (114.5 167 kJ/mol for chars, respectively). The combination an additional first-order devolatilization stage produces...

The pyrolysis of a packed bed fir wood particles, after impregnation with KOH, is investigated. For heating temperature 800 K, maximum variations in the characteristics are observed for KOH concentrations below 1%. Decomposition temperatures become lower (35−70 K), and conversion times rapidly more than halved. Also, char, water, gas yields increase (factors 1.4, 1.6, 1.7, respectively) at expense liquid-phase organic products. Levoglucosan presents very steep decay, whereas diminution...

Motivated by the production of fine chemicals and improvement flame retardance properties, experiments have been performed with a fixed-bed reactor to investigate catalytic action exerted zinc chloride on fir wood pyrolysis (catalyst concentrations between 0 16% dry basis heating temperatures 650 900 K). It has observed that this Lewis acid acts as dehydrating cross-linking agent promoting formation char water total yields up about 73%. As consequence, majority organic condensable products...

The pyrolysis of corncobs impregnated with variable amounts zinc chloride (ZnCl2) (up to 11%, on a dry sample mass basis) is investigated and compared fir wood results. As expected, continuous increase the amount catalyst in observed formation rates char water (total yields from 46% up 64%) associated decline organic condensable products (from 38% 18%) gas 13% 9%). Moderate ZnCl2 concentrations (2%−5%) favor production levoglucosenone trace 1%), acetic acid 4% 6%), furfural 0.65% 6%)....

Acidic pyrolysis of corncobs is carried out at 800 K in a packed-bed reactor using several catalysts (H2SO4, H3PO4, H3BO3, (NH4)2SO4, ZnCl2, NiCl2, MgCl2, and Fe2(SO4)3). In all cases, the yields char, water, some condensable organic compounds (acetic acid, levoglucosenone, 1,4:3,6-dyanhydro-α-d-glucopyranose, furfural) are significantly increased expense phenolic carbohydrate products typical uncatalyzed pyrolysis. The maximum furfural (FF) around 5–6% for H2SO4, Fe2(SO4)3 ,and ZnCl2...

The acid-catalyzed pyrolysis of corncobs is investigated for the production chemicals (in particular furfural) and bioproducts. Particles, preimpregnated with H2SO4 concentrations up to about 4% (dry sample mass basis) predried at 343 K, are exposed in form a packed-bed heating temperature 800 K. gas release rate remains approximately constant, value half respect maximum detected acid-free samples, large part process transients. Conversion times roughly increased by 50% while reaction...

Pyrolysis is carried out using beech wood for packed beds, consisting of pellets and particles various sizes, a block in the same shape size as beds. The different physical properties samples affect heat- mass-transfer rates and, consequently, conversion time. However, effects on yields composition lumped product classes are generally negligible. An exception observed beds made pulverized material, where re-evaporation pyrolysis vapors, previously migrated condensed cold zones, result...

Abstract Reaction‐induced overheating during the pyrolysis of lignocellulosic material has been reported by various authors, but it is still one less understood aspects process. This Review outlines experimental results for a mixed kinetic‐transport control in which exothermicity displayed clearly. The thermal conditions and feedstock properties that enhance these events are discussed. Intraparticle activity, at microscopic level, homogeneous heterogeneous reactions vapor‐phase tars main...

Abstract A 1‐D transient mathematical model was studied for a composite system consisting of substrate (steel) and an intumescent coating exposed to radiative heating. By applying simple heat conduction equation the first material, general proposes three components, which degrade according independent finite‐rate reactions. Mass transfer take place across variable volume medium, including simplified mechanism bubble dynamics material swelling. parametric analysis clarifies role several...