Pyrolysis Of Pine Wood Research Articles

Iron nanoparticles in situ encapsulated in biochar-based carbon as an effective catalyst for the conversion of biomass-derived syngas to liquid hydrocarbons

Biochar, a by-product from the fast pyrolysis of pine wood, was used as the support material for the synthesis of carbon-encapsulated iron nanoparticles. The nanoparticles were characterized for physicochemical properties by multiple morphological and structural methods (e.g., SEM, TEM, XRD, FTIR, and TPD). The Fischer–Tropsch synthesis (FTS) process was carried out to evaluate the catalytic activity of the nanoparticles on conversion of biomass-derived synthesis gas (bio-syngas) to liquid hydrocarbons. Characterization results revealed that the nanoparticles had core–shell structures with iron in situ encapsulated within a graphitic shell. Moreover, significant amounts of iron carbide (mainly Fe3C) were formed as an interface between the carbonaceous shell and the iron core. FTS tests indicated that such carbon-encapsulated iron nanoparticles possessed a high activity on conversion of bio-syngas and good selectivity towards liquid hydrocarbons (of which olefins were the dominant product). Over a 1500 h testing period, the nanoparticles showed striking stability against deactivation, with CO conversion maintained at about 95% and liquid hydrocarbon selectivity at about 68%.

Catalytic upgrading of biomass pyrolysis vapours using faujasite zeolite catalysts

Bio-oil produced via fast pyrolysis of biomass has the potential to be processed in a FCC (fluid catalytic cracking) unit to generate liquid fuel. However, this oil requires a significant upgrade to become an acceptable feedstock for refinery plants due to its high oxygen content. One promising route to improve the quality of bio-oil is to pyrolyse the parent biomass in the presence of a catalyst. This work investigates the influence of faujasite catalysts on the pyrolysis of pinewood. Pyrolysis process with Na-faujasite, Na0.2H0.8-faujasite, and H-faujasite (Na-FAU, Na0.2H0.8-FAU, and H-FAU) were carried out in a fixed-bed reactor at 500 °C. It is shown that, in the same condition, catalytic upgrading of pyrolysis vapour is superior to in-situ catalytic pyrolysis of biomass when it comes to quality of bio-oil. The yields of coke, gas and water increase while that of organic phase decreases proportional with the concentration of protons in catalysts. Compared to the other two catalysts, Na0.2H0.8-FAU removes the most oxygen from bio-oil, reduces amount of acids and aldehydes/ketones which result in a higher energy-contained and more stable oil with less corrosive property. However, the biggest contribution to the oxygen removal is via the formation of reaction water, which is not an optimum path. This leaves space for future development.

Stepwise Fast Pyrolysis of Pine Wood

This paper reports the yields and product composition obtained from the stepwise pyrolysis of pine wood in a fluidized bed reactor. The first step temperature was varied between 260 °C and 360 °C. After the first step, the solid residue was cooled to ambient temperature and pyrolyzed again at 530 °C. If the first step temperature was below 290 °C, the cumulated yields (the sum of steps 1 and 2) were identical to yields of the single-step experiment at 530 °C. This indicates that the chemical and transfer processes taking place below 290 °C do not lead to chemical and structural changes that affect the outcome of the processes occurring in the temperature range from 290 °C to 530 °C. When the first step temperature was higher than 310 °C the cumulated yields of char, water, light organic compounds, and furans were higher, whereas the cumulated yields of volatiles (gases plus organic liquids) were lower than those obtained if the pyrolysis was conducted in a single step at 530 °C. To explain these observations, a mechanism is proposed in which the main emphasis lies on the competition between routes that lead to char formation and routes that release compounds from the biomass particle. Single compounds and lumped groups could not be concentrated with the stepwise approach. A separation into lighter and heavier oils turned out to be possible.

On-line product analysis of pine wood pyrolysis using synchrotron vacuum ultraviolet photoionization mass spectrometry

The pyrolysis process of pine wood, a promising biofuel feedstock, has been studied with tunable synchrotron vacuum ultraviolet photoionization mass spectrometry. The mass spectra at different photon energies and temperatures as well as time-dependent profiles of several selected species during pine wood pyrolysis process were measured. Based on the relative contents of three lignin subunits, the data indicate that pine wood is typical of softwood. As pyrolysis temperature increased from 300 to 700 °C, some more details of pyrolysis chemistry were observed, including the decrease of oxygen content in high molecular weight species, the observation of high molecular weight products from cellulose chain and lignin polymer, and potential pyrolysis mechanisms for some key species. The formation of polycyclic aromatic hydrocarbons (PAHs) was also observed, as well as three series of pyrolysis products derived from PAHs with mass difference of 14 amu. The time-dependent profiles show that the earliest products are formed from lignin, followed by hemicellulose products, and then species from cellulose.

Demineralization of wood using wood-derived acid: Towards a selective pyrolysis process for fuel and chemicals production

A process concept for the pyrolysis of demineralized wood to obtain high organic and especially levoglucosan yields is proposed and tested experimentally. The wood is demineralized using organic acids, produced and concentrated within the same pyrolysis process.Pine wood was pyrolyzed in a fluidized bed fast pyrolysis reactor (150g feed per test) in which the produced vapors were condensed in two stages. The liquid obtained in the first condenser, operated at 80°C (outgoing gas), contains the heavy compounds, like the lignin derived aromatic compounds and anhydro-sugars. In the second condenser, operated at −5°C, most of the light compounds (including the acids) are collected. Pine wood was washed with this second condenser liquid at 90°C for 2h to remove the (alkali) minerals to increase the selectivity towards levoglucosan during pyrolysis.Washing pine wood with the second condenser liquid prior to pyrolysis of the biomass, effectively removed the alkali ions initially present in biomass. No significant consumption of acetic acid during the washing step was observed. Rinsing of the biomass after acid washing is required for maximal levoglucosan production, to remove the washing liquid containing the dissolved minerals.Fast pyrolysis of pine wood washed with second condenser liquid combined with rinsing resulted in an increase in organic oil yield and is accompanied with a decrease in water and char yield. The levoglucosan production increased strongly (up to 18wt% on biomass intake) and was concentrated, by staged condensation, in a single fraction up to a concentration of 37wt% in the first condenser oil. The obtained levoglucosan yield is comparable to yields reported in literature obtained by mineral acid washing.The presented concept for demineralization wood, by washing with an aqueous pyrolysis fraction produced from the biomass itself, prior to pyrolysis is demonstrated to be an interesting sustainable process to increase both the organic oil yield and the production of levoglucosan.

Production of p‐Xylene from Biomass by Catalytic Fast Pyrolysis Using ZSM‐5 Catalysts with Reduced Pore Openings

Pores for thought: Chemical liquid deposition of silica onto ZSM-5 catalysts led to smaller pore openings that resulted in >90% selectivity for p-xylene over the other xylenes in the catalytic fast pyrolysis of furan and 2-methylfuran (see scheme). The p-xylene selectivity increased from 51% with gallium spray-dried ZSM-5 to 72% with a pore-mouth-modified catalyst in the pyrolysis of pine wood.

Characteristics of pine wood oxidative pyrolysis: Degradation behavior, carbon oxide production and heat properties

Oxidative pyrolysis of pine wood was studied by thermogravimetric analysis (TGA) coupled with mass spectrometer (MS) and differential scanning calorimetry (DSC) methods. The effects of oxygen concentration on pyrolysis behavior, carbon oxide production and heat properties were investigated. Several parameters were defined to evaluate the oxygen influence. It was found that oxygen dramatically promotes the oxidative degradation and char oxidation rate. The reactivity index was found to be proportional to the oxygen concentration, which suggested that oxidative degradation reactions were under increasingly kinetic control in elevated oxygen concentration environments. Carbon oxides evolution properties were investigated. There are two releasing peaks in MS curves for oxidative condition comparing with one peak under inert condition. They are related with oxidative degradation and char oxidation, respectively. Both total amounts and rates of carbon oxides emission were found to increase with oxygen concentration. The cumulative emission ratio of CO to CO2 first decreases then increases with oxygen concentration with 10% as turning point. It may be caused by different oxygen diffusion behaviors with variable oxygen concentrations. The absolute reaction heat value of oxidative pyrolysis (−7.23MJkg−1, 5% O2) is much larger than that of inert condition (+0.28MJkg−1). Increasing of oxygen concentration results in an increase of heat emission. Comparing with pine wood low heat value, the net heat emission efficiencies under different oxygen concentrations (5%, 10%, 15%, 21%) are 39.73%, 44.84%, 68.90% and 78.41%, respectively.

Catalytic Pyrolysis of Biomass over H+ZSM-5 under Hydrogen Pressure

Catalytic pyrolysis of pine wood was carried out using H+ZSM-5 in a hydrogen environment. The first objective of this study was to investigate the effect of hydrogen pressure on catalytic pyrolysis using H+ZSM-5. The study found that there was no increase in the aromatic hydrocarbons as the hydrogen pressure increased. The second objective of this study was to incorporate a hydrogenation effect in addition to catalytic-cracking during pyrolysis so that the amount of hydrocarbons in the bio-oil could be increased. The effect of hydrogen pressure on the Mo-impregnated catalyst was investigated in pine wood pyrolysis. The Mo/ZSM-5 catalyst was not as active as H+ZSM-5 in lower pressures (100–300 psi); however, at 400 psi, Mo/ZSM-5 gave more hydrocarbons than H+ZSM-5 did. A significant increase in aromatic hydrocarbons was found when the H+ZSM-5 catalysts were impregnated with metals (Ni, Co, Mo, and Pt) as compared to just the zeolite at 400 psi. On average, 42.5 wt.% of biomass carbon was converted into hyd...

Dynamic Mechanical Properties of Polymeric Diphenylmethane Diisocyanate/Bio-Oil Adhesive System

Abstract Bio-oil obtained from the pyrolysis of pine wood was mixed with polymeric diphenylmethane diisocyanate (pMDI) to form an adhesive binder system for flakeboard. Acetone was added for reducing the viscosity of the adhesive system. The thermal properties and curing behavior of five different adhesive mixes were examined using dynamic mechanical analysis (DMA). Temperature scans were performed in a range of 50°C to 200°C with a heating rate of 10°C/min, frequency of 1 Hz, and strain amplitude of 15 μm. Results indicated that less time was needed to reach the maximum storage modulus of the adhesive mix with an increase in bio-oil content. The adhesive with the pMDI/bio-oil ratio of 25/75 presented the fastest curing speed but the lowest modulus value at temperatures of approximately 100°C. The pMDI-acetone adhesive showed the best thermal mechanical properties among the five adhesive binder systems.

Catalytic fast pyrolysis of wood and alcohol mixtures in a fluidized bed reactor

Catalytic fast pyrolysis (CFP) of pine wood, alcohols (methanol, 1-propanol, 1-butanol and 2-butanol) and their mixtures with ZSM-5 catalyst were conducted in a bubbling fluidized bed reactor. The effects of temperature and weight hourly space velocity (WHSV) on the product carbon yields and selectivities of CFP of pure pine wood and methanol were investigated. A maximum carbon yield of petrochemicals (aromatics + C2–C4olefins + C5 compounds) from pine wood of 23.7% was obtained at a temperature of 600 °C and WHSV of 0.35 h−1. A maximum petrochemical yield from methanol of 80.7% was obtained at a temperature of 400 °C and WHSV of 0.35 h−1. Thus, the optimal conditions for conversion of pine wood and methanol are different. The CFP of pine wood and methanol mixtures was conducted at 450 °C and 500 °C. The hydrogen to carbon effective (H/Ceff) ratio of the feed was adjusted by changing the relative amount of methanol and wood. The petrochemical yield was a function of the H/Ceff ratio and more petrochemicals are produced from biomass when methanol is added to the CFP process. Co-feeding of 12C pine wood and 13C methanol was carried out at 450 °C. The isotopic study showed that all the hydrocarbon products contained mixtures of 12C and 13C, indicating that the carbon is mixed within the zeolite. However, the distribution of carbon was skewed depending on the product. The toluene, xylene, propylene and butenes contained more 13C. The naphthalene and ethylene contain more 12C. Wood was also co-processed with 1-propanol, 1-butanol, and 2-butanol, which showed a similar effect as methanol with an increasing petrochemical yield with an increasing H/Ceff ratio of the feed. This paper demonstrates that CFP can selectively produce a mixture of compounds where the overall yield is a function of the H/Ceff ratio of the feed.

Catalytic Pyrolysis of Pine Biomass Over H-Beta Zeolite in a Dual-Fluidized Bed Reactor: Effect of Space Velocity on the Yield and Composition of Pyrolysis Products

A dual-fluidized bed reactor was applied in the pyrolysis of pine wood and catalytic upgrading of the pyrolysis vapors over H-Beta zeolite. The temperatures of the pyrolysis and catalytic upgrading reactors were 400 and 440 °C, respectively. The effect of space velocity on the yield and composition of pyrolysis products was investigated. It was found that the catalytic upgrading affects all pyrolysis products, except the char yield which can be considered constant at all space velocities. By lowering the space velocity the gas, water and coke yields increased at the cost of the organic phase of the bio-oil. The coke yield was fairly high, 11 wt% of the biomass, at the lowest space velocity. The spent catalysts could be regenerated by burning away the formed coke and thereby regaining the surface area and most of the acid sites.

Thermopower coefficient of pine-wood biocarbon preforms and the biocarbon-preform/copper composites

The thermopower S(T) of the composites prepared by filling empty sap channels in high-porosity biocarbon preforms of white pine wood by melted copper in vacuum and the thermopower S(T) of these preforms have been measured in the temperature range 5–300 K. The biocarbon preforms have been obtained by pyrolysis of pine wood in an argon flow at two carbonization temperatures, 1000 and 2400°C. An analysis of the experimental data has demonstrated that the thermopower of the composites is determined by the contribution related to the copper filling the channels of the biocarbon preform and exhibits a characteristic temperature dependence with a deep minimum close to 20 K. This suggests that copper in the preform channels is essentially a Kondo alloy with the iron and manganese impurities entering into it from the carbon preform in the course of infiltration of melted copper.

Catalytic upgrading of woody biomass derived pyrolysis vapours over iron modified zeolites in a dual-fluidized bed reactor

In this paper, the influence of the proton forms of beta, Y and ferrierite zeolites and their iron modified counterparts during upgrading of pine wood pyrolysis vapours under nitrogen atmosphere was investigated. A dual-fluidized bed reactor was used where in the first bed pyrolysis of pine wood occurred, and in the second upgrading of the pyrolysis vapours over zeolites was conducted. The temperature for pyrolysis and upgrading was 400 and 450 °C, respectively. De-oxygenation reactions over the proton form and iron modified zeolites increased compared to the non-catalytic pyrolysis. The increased selectivity towards organic compounds through de-oxygenation could be noticed as a higher water yield and CO formation.

Pyrolysis of pine wood in a slowly heating fixed-bed reactor: Potassium carbonate versus calcium hydroxide as a catalyst

Catalytic pyrolysis of pine wood was carried out in a fixed-bed reactor heated slowly from room temperature to 700 °C under a stream of purging argon to examine the effects of the physically mixed K 2CO 3 or Ca(OH) 2 on the pyrolysis behaviors. K 2CO 3 demonstrated a stronger catalysis for decomposition of hemicellulose, cellulose and lignin constituents, leading to the reduced yield of liquid product in conjunction with the increased yields of gaseous and char products because of the promoted secondary reactions of liquid product. With the addition of 17.7 wt.% of K 2CO 3, none of saccharides, aldehydes and alcohols was formed and the formation of acids, furans and guaiacols was substantially reduced, whereas the yields of alkanes and phenols were increased. Potassium led to an increase in the cumulative yields of H 2, CO 2 and CO at 700 °C. Ca(OH) 2 somewhat promoted the decomposition of cellulose and lignin constituents, and the effect of Ca(OH) 2 on the yields of liquid and char was opposite to that of K 2CO 3. With the addition of 22.2 wt.% Ca(OH) 2, some groups of liquid product such as acids and aldehydes disappeared completely and the yields of saccharides, furans and guaiacols were somewhat reduced, while the yield of alcohols was remarkably increased in contrast to the result of K 2CO 3. The addition of Ca(OH) 2 did not significantly change the total yield of gaseous product at 700 °C but enhanced the yield of H 2.

Characterization and application of chars produced from pinewood pyrolysis and hydrothermal treatment

Two types of pinewood chars, hydrothermal char (H300) and pyrolytic char (P700) from biomass-to-energy conversion were characterized and used as adsorbent for the copper removal from aqueous solution. The result showed that the pinewood underwent a deeper carbonization during pyrolysis process and more activated sites available and stable carbon–oxygen complex existed after hydrothermal treatment. Comparing with raw pinewood, hydrothermal treatment increased 95% total oxygen-containing groups (carboxylic, lactone and phenolic group) while 56% oxygen-containing groups decreased after pyrolysis process. SEM analysis indicated that both hydrothermal and pyrolytic processes developed rough surface with new cavities on the chars, and the BET surface area were 21 and 29 m 2/g for H300 and P700, respectively. Although H300 had lower surface area, its adsorption capacity for copper was much higher than P700 since ion-exchange reaction was the predominant removal mechanism by H300, while physical adsorption dominated by P700. The adsorption data could be well described by Langmuir isotherm model for copper onto both H300 and P700.

Pyrolysis of Softwood Carbohydrates in a Fluidized Bed Reactor

In the present work pyrolysis of pure pine wood and softwood carbohydrates, namely cellulose and galactoglucomannan (the major hemicellulose in coniferous wood), was conducted in a batch mode operated fluidized bed reactor. Temperature ramping (5 °C/min) was applied to the heating until a reactor temperature of 460 °C was reached. Thereafter the temperature was kept until the release of non-condensable gases stopped. The different raw materials gave significantly different bio-oils. Levoglucosan was the dominant product in the cellulose pyrolysis oil. Acetic acid was found in the highest concentrations in both the galactoglucomannan and in the pine wood pyrolysis oils. Acetic acid is most likely formed by removal of O-acetyl groups from mannose units present in GGM structure.

Catalytic performance of porous carbons obtained by chemical activation

Porous carbons were prepared by the pyrolysis of pinewood in nitrogen at 773 K, followed by chemical activation using different concentrations of KOH in nitrogen at 973 K. Both water-washed and acid-washed samples exhibited much higher specific surface areas than unactivated carbon. The water-washed sample showed strong basicity and a high catalytic performance in the decomposition of isopropanol, even higher than superbase 26%KNO 3/γ-Al 2O 3. Moreover, these porous carbons can act as water-resistant solid bases. The formation of the insoluble basic sites is most possibly related to the intercalation of potassium in the carbon during the chemical activation.

X-ray microtomographic imaging of charcoal

We assess the potential of X-ray microtomography as a tool for the non-destructive, three-dimensional examination of the internal structure of charcoal. Microtomographic analysis of a series of charcoals produced by the experimental pyrolysis of pine wood at temperatures from 300 and 600 °C in nitrogen only and in nitrogen mixed with 2% oxygen indicates that, despite substantial shrinkage, observed porosity, pore size and pore connectivity are all increased by pyrolysis and also by chemical oxidation. Analysis of a number of altered and unaltered archaeological and geological charcoals has demonstrated the capacity of the technique to identify and map the distribution of authigenic mineral contamination within charcoal fragments. The results are of significance to radiocarbon dating in that they provide insights into the mechanisms by which charcoal can be contaminated by extraneous carbon in the natural environment.

Filtration Combustion of Humid Fuels

A comparative study of the filtration combustion of two types of fuel in mixtures with an inert material at various degrees of humidity was performed. The fuels were activated birch charcoal and pinewood. It was demonstrated that the combustion of activated charcoal was only slightly affected by humidity. In the case of pinewood combustion, an increase in the fuel humidity caused substantial decreases in the gasification mass rate and temperature. The composition of the gaseous products was found to change only for mixtures containing a large amount of pinewood with a humidity of more than 35%. This can be accounted for by a change in the extent of pinewood pyrolysis.

Understanding the pyrolysis of CCA-treated wood: Part I. Effect of metal ions

The influence of several inorganic compounds (K 2Cr 2O 7, CrO 3 and CuSO 4) on the pyrolysis of southern pine wood has been investigated. The wood powder was pre-treated with various inorganic compound solutions prior to the pyrolysis and the distribution and yields of the pyrolysis products were obtained by gas chromatography and quantitative 31P nuclear magnetic resonance (NMR) analyses. Our experiments showed that K 2Cr 2O 7 and CuSO 4 salts promoted the formation of levoglucosan (LG). In particular, the former providing higher LG yields up to 26.7%. The CrO 3 treatment induced the production of low tar and high char yields, with a very low yield of LG and high yield of levoglucosenone (LGO). The underlying reasoning behind these findings may be due to an acidic catalysis mechanism, which promotes cellulose depolymerization and dehydration processes. Due to acid-catalyzed lignin condensation reactions, the yield of lignin degradation products from the pyrolysis of pre-treated wood was found to dramatically decrease in comparison to untreated wood.