Fast Pyrolysis Of Pine Sawdust Research Articles

Oxidative fast pyrolysis of biomass in a quartz tube fluidized bed reactor: Effect of oxygen equivalence ratio

The effect of oxygen equivalence ratio (ER) on oxidative fast pyrolysis of pine sawdust was investigated in a quartz tube fluidized bed reactor. The results showed that the introduction of oxygen into fluidizing gas would mainly oxidize the biochar, thus provided the largest contribution to heat demand during biomass pyrolysis towards autothermal operation. The increase of ER from 0 to 11.15% decreased the biochar yield from 21.03 to 9.5 wt%. The enthalpy for fast pyrolysis of pine sawdust was about 1084.49 kJ/kg, and a theoretical ER to achieve autothermal pyrolysis was thus calculated as ∼3.92%. The addition of oxygen indeed changed the formation and distribution of bio-oil. With ER of 6.47%, although the bio-oil yield decreased slightly, the light compounds in bio-oil (e.g., linear alcohols/carbonyls/acids, furan compounds and cyclopentanones/cyclohexanones) were largely consumed, while the heavy compounds (e.g., phenols/aromatic hydrocarbons and anhydrosugars) were mostly retained with the formation of anhydrosugars being promoted.

Effects of microwave pretreatment on catalytic fast pyrolysis of pine sawdust

In this work, thermal behavior and pyrolysis products of pine sawdust after treated by different microwave pretreatment condition had been studied. Surface structure of samples getting collapsed after microwave pretreatment and the characteristics of thermal decomposition with CaO addition under four kinds heating rates was investigated by thermogravimetric analyzer. Pyrolysis process was carried and the products composition were detected both on Pyrolysis-Gas Chromatography/Mass Spectrometry. Under the condition of 567 W power treatments for 3 min, the yield of phenols rose from 3.64% to 18.21% and the ketones decreased from 55.80% to 40.27%. The activation energy was calculated by Flynn-Wall-Ozawa method. After microwave pretreatment, the activation energy of pine sawdust reach the maximum increase 7.26% at 329 W for 3 min, which meant that microwave pretreatment had little positive effect on promoting the pyrolysis reaction.

Influence of the Composition of Raw Bio-Oils on Their Valorization in Fluid Catalytic Cracking Conditions

This study delves on the catalytic cracking in fluid catalytic cracking (FCC) conditions of two raw bio-oils of different compositions, obtained from the fast pyrolysis of pine sawdust (PBO) and black poplar sawdust (BPBO). The FCC runs have been carried out using an equilibrated FCC catalyst at 550 °C, 6 s of contact time and in the C/O (catalyst/bio-oil) range of 1.8–10 gcat (gfeed)−1. The effect of the C/O ratio has been studied on product distribution (CO + CO2, carbon products, water, and coke); on the yields of CO + CO2, dry gas (C1–C2), liquefied petroleum gases (C3–C4), gasoline (C5–C11), light cycle oil (C12–C22), and coke; on the conversion of specific bio-oil oxygenates; and on the hydrocarbon and oxygenates composition of the gasoline product. A gasoline yield of 45.7 wt % was achieved, with a hydrocarbon yield of 29.6 wt % and a liquid fraction (C5–C20) yield of 13.8 wt % at C/O = 7.3 gcat (gfeed)−1. The differences in the results of both bio-oils can be explained from their different composi...

Synthesis and Characterization of Novel Catalytic Materials Using Industrial Slag: Influence of Alkaline Pretreatment, Synthesis Time and Temperature

Industrial ferrous wastes found their application in construction. However, they are mostly stored polluting the environment. In the current work, possibility of value added products synthesis from steel slag with their further use as catalysts was investigated. Slag-based catalysts were obtained by alkaline treatment with sodium hydroxide by variation of synthesis parameters. The physico-chemical properties of the synthesized materials were determined by N2-physisorption, SEM, EDX, TEM, XRD and TPD. Slag-based catalysts were applied in the transformation of wood biomass, namely softwood sawdust. Novel catalytic materials synthesized from industrial slag exhibited the presence of strong basic sites and highly crystalline phases of SiO2, Al2O3, CaCO3, Ca(OH)2, Fe2O3, MgO and TiO2. Alkaline treatment of the raw material promoted creation of mesoporosity and an increase of the surface area. Catalytic fast pyrolysis of pine sawdust displayed variations in the yields of the reaction products in the presence of catalysts as compared to thermal fast pyrolysis.Graphical

Analysis of Bio‐Oil Derived from Catalytic Pyrolysis of Pine Sawdust over Sodium Salts‐Supported γ‐Al2O3

Catalytic pyrolysis of pine sawdust with five sodium salts‐supported γ‐Al2O3 was performed in a fixed‐bed reactor at 500°C for liquid products. The liquid products were analyzed for its physics and chemical properties, such as product yield, oil phase proportion and yield, water content, chemical composition, elemental analysis, and calorific value. The results indicate that liquid yields decreased with the five catalysts compared with non‐catalytic pyrolysis, whereas phase separation (oil and aqueous phases) was observed. The oil phase water content drops sharply to around 10% compared to non‐catalytic bio‐oil (30%). The acid was not observed in the chemical composition of the oil phase product when the catalysts were present. The oxygen content of the oil phase products was significantly reduced. Of the five catalysts, Na2SiO3/γ‐Al2O3 catalyst showed better catalytic performance for its maximum oil phase product yield and oil quality. High heat value of the five oil phase products was all above 30.0 MJ/kg with this catalytic system. The new sodium ion species generated from the combination of sodium salts and γ‐Al2O3, which may be responsible to the improvement of bio‐oil quality. Furthermore, the excess sodium salts on the γ‐Al2O3 surface play an important role on the fast pyrolysis of pine sawdust. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019

Co-upgrading of raw bio-oil with kitchen waste oil through fluid catalytic cracking (FCC)

Raw bio-oil was produced from fast pyrolysis of pine sawdust in a fluidized-bed boiler at 550 °C. Then the raw bio-oil is partially mixed with kitchen waste oil (100:0, 50:50, 0:100 by weight) and subsequently subjected to off line co-catalytic cracking process for upgrading over HZSM-5. The raw bio-oil mixed with kitchen waste oil test shows that the co-catalytic cracking improves the organic bio-oil yield and inhibits the coke formation. The oxygen content of organic bio-oil decreased significantly after upgrading. The reaction pathway of co-upgrading is proposed, which shows that kitchen waste oil, as a hydrogen supplier, transform hydrogen from high saturation degree to the unsaturation oxygenated compounds to form hydrocarbons. Co-catalytic cracking process of raw bio-oil and kitchen waste oil not only can be used in raw bio-oil upgrading but also can recycle kitchen waste oil with relatively low cost. Moreover, the deactivation catalysts are analyzed by TG-FTIR (Thermogravimetric-Fourier Transform Infrared spectroscopy) and SEM (Scanning Electron Microscope).

Stability of a Rh/CeO2–ZrO2 Catalyst in the Oxidative Steam Reforming of Raw Bio-oil

The oxidative steam reforming (OSR) of raw bio-oil (obtained by fast pyrolysis of pine sawdust) has been studied on a Rh/CeO2–ZrO2 catalyst under a wide range of operating conditions (600–750 °C; steam-to-carbon molar ratio, 3–9; oxygen-to-carbon molar ratio, 0.34; space time, 0.15–0.6 gcatalyst h/gbio-oil) in order to delimit the suitable conditions for high and stable H2 production. The runs were conducted in a two-step system provided with a thermal step (at 500 °C) for bio-oil vaporization and pyrolytic lignin retention, followed by an online catalytic reforming step in a fluidized bed reactor. The spent catalyst was characterized by temperature-programmed oxidation, temperature-programmed reduction, and transmission electron microscopy in order to ascertain the causes of deactivation and the effect of the reaction conditions on these causes. The evolution with time on stream of both bio-oil oxygenates conversion and yields of reaction products shows different periods and catalyst states, with two sha...

Steam reforming of raw bio-oil over Ni/La2O3-αAl2O3: Influence of temperature on product yields and catalyst deactivation

The hydrogen production by steam reforming (SR) of raw bio-oil (obtained by fast pyrolysis of pine sawdust) has been studied in a continuous two-step process, which consists of a thermal treatment at 500 °C, followed by SR in a fluidized bed reactor with Ni/La2O3-αAl2O3 catalyst. The effect of SR temperature on bio-oil conversion, product yields and catalyst deactivation was evaluated in the 550–700 °C range. The bio-oil conversion and H2 yield were significantly enhanced by increasing temperature. A H2 yield of around 88% and low catalyst deactivation were achieved at temperatures above 650 °C, for a S/C (steam/carbon) ratio of 6 and space-time of 0.10 gcatalysth/gbio-oil. The influence temperature has on product yields and catalyst deactivation was explained by the different nature of the coke deposited. The temperature-programmed oxidation (TPO) curves of coke combustion allow identifying two fractions: i) Coke I, which is the main responsible for deactivation (by encapsulating the Ni sites), whose formation depends on the concentration of bio-oil oxygenates; ii) Coke II, which has filamentous nature and CO and CH4 as main precursors. The effect of temperature on the formation of both types of coke depends on the space–time. Thus, for low values (0.04 gcatalysth/gbio-oil) there is significant formation of both types of coke, with their content increasing with temperature. For higher values (0.38 gcatalysth/gbio-oil), the increase in reaction temperature promotes the removal of coke I, and therefore this is the prevailing fraction at 550 °C and is negligible at 700 °C. This fact is of special relevance for attenuating the Ni/La2O3-αAl2O3 catalyst deactivation.

Study on pine sawdust pyrolysis behavior by fast pyrolysis under inert and reductive atmospheres

Fast pyrolysis of pine sawdust (PS) was investigated in a drop tube quartz reactor to understand the effects of temperature and atmosphere (Ar and H2) on the product yields, gas composition, bio-oil characteristics (organic composition and molecular mass distributions (MMDs)), and the carbon and oxygen conversion. The pyrolysis behavior and typical products from PS pyrolysis were also conducted using a thermogravimetry-mass spectroscopy (TG-MS) and pyrolysis-gas-chromatography/mass spectrometry (Py-GC/MS). The results show that the highest oil yields can be obtained at 500°C of 55.09 and 54.41wt.% under Ar and H2 atmosphere, respectively. In comparison to an inert atmosphere, H2 created lower oil yields but higher gas yields, especially for CO and CH4 yields, and narrower MMDs, smaller Mn and Mw, and fewer char especially at high temperatures. The high temperatures and H2 atmosphere contribute to the oxygen and carbon transferring from material to volatile, especially to the gaseous products. H2 can promote the secondary cracking of macromolecules and weaken the re-polymerization of anhydrosugar and lignin oligomers.

Effect of Hot Vapor Filter Temperature on Mass Yield, Energy Balance, and Properties of Products of the Fast Pyrolysis of Pine Sawdust

The fast pyrolysis in a fluidized-bed reactor using pine sawdust has been studied at 500 °C with ceramic hot vapor filter (HVF). The effects of HVF temperature (350, 400, 450, and 500 °C) on mass balance, energy balance, and physical properties of pyrolysis products were investigated. The results were reported that the maximum yields of bio-oil and organic liquid were 58.7 and 41.6 wt % at HVF temperatures of 350 and 400 °C, respectively. When HVF temperature increased from 350 °C to 500 °C, the maximum biochar yield was 25.3 wt % at 350 °C, while the minimum noncondensable gas (NCG) yield was 19.2 wt % at 400 °C. The energy consumption of pine sawdust pyrolysis was calculated as 2.38 MJ/kg. The optimized HVF temperature for energy balance was 450 °C. Under these conditions, the potentially recovered energy of bio-oil and total pyrolysis products reached maximum values of 7.49 MJ/kg and 17.91 MJ/kg, respectively. Maximum energy recovery ratios of total pyrolysis products and bio-oil were 0.92 and 0.39, re...

Study of a new combined method for pre-extraction of essential oils and catalytic fast pyrolysis of pine sawdust

A new combined method for the pre-extraction of essential oils (EOs) and the uniformly dispersion of alkaline earth metal oxide (AEMO) on pine sawdust (PS) was investigated. EOs were firstly extracted from PS after mixing with a certain amount of AEMO through steam distillation (SD), and then the pretreated PS was utilized in the process of fast pyrolysis to produce the upgraded bio-oil. A maximum extraction yield of EOs was 1.61 wt% from PS mixed with 5 wt% CaO within 300 min, compared with 1.21 wt% from the control (raw PS). The proportion of alcohols in EOs increased significantly when using PS mixed with AEMO. When PS was pretreated by the combined AEMO mixing and SD, the content of hydrocarbons in organic phase of the bio-oil increased significantly while that of acids and CnHmOx decreased. The analysis of physicochemical properties for the bio-oil further demonstrated that the quality of bio-oil was improved based on the new pretreatment method. Furthermore, the maximum bio-oil yield was obtained at pyrolysis temperature of 500 °C in almost all cases.

Influence of industrial alcohol and additive combination on the physicochemical characteristics of bio-oil from fast pyrolysis of pine sawdust in a fluidized bed reactor with hot vapor filter

Effects of different mass fractions of industrial alcohol additive (10% and 20%) and additive combination (ethanol: 6.58%, acetonitrile: 1.00%, methyl acetate: 2.42%) on the physicochemical characteristics of pine sawdust bio-oil aging for three months by fast pyrolysis of 1–5 kg/h bench-scale fluidized bed reactor with hot vapor filter were investigated. The results indicated that addition of industrial alcohol and additive combination had a significant effect on improving the physicochemical characterization of bio-oil. The additives could significantly lower the viscosity and instantly increase pH value of the bio-oil remarkably and also delay the aging rates of the bio-oil. Results showed that compared with the blank (bio-oil without additive), the pH values of the bio-oils with 10% industrial alcohol (10% IA bio-oil), 20% industrial alcohol (20% IA bio-oil), and additive combination (AC bio-oil) were immediately increased by 12%, 12%, and 21%, respectively when the additives were added. After stored for 90 days, viscosities of crude bio-oil, 10% IA bio-oil, 20% IA bio-oil and AC bio-oil were increased by 200%, 54%, 69%, and 62%, respectively. Two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOFMS) analysis indicated that the aged bio-oil after 90 days storage had a lower levels of phenols than that of the crude bio-oil and the contents of ketones and esters were increased. FT-IR analysis demonstrated that the structures of non-volatile residue of bio-oils were changed and polymerization occurred with other compounds such as alcohols and aldehydes during storage.

Combustion kinetics of pine sawdust biochar

The combustion kinetics of biochar derived from fast pyrolysis of pine sawdust was investigated by using nonisothermal thermogravimetric analysis under air atmosphere at different heating rates. The experimental conversion (α–T) curves contain some experimental errors, and the corresponding derivative conversion (dα/dT–T) curves have many fluctuations. Two strategies of obtaining the smooth dα/dT–T curves were used based on the robust locally weighted scatterplot smoothing method coupled with the corrected AIC smoothing parameter selection method. In the strategy of firstly smoothing α–T data and then differentiating smoothed α–T data, although the smoothed α–T data are relatively smooth, the dα/dT–T curves obtained from the differentiation of the smoothed α–T data have fluctuations. In the strategy of firstly differentiating α–T data and then smoothing dα/dT–T data, the obtained dα/dT–T curves with the optimal smoothing parameters are smooth enough, which indicates that the second strategy is effective. The isoconversional kinetic analysis of the smoothed dα/dT–T curves was performed by using the Friedman differential isoconversional method. The effective activation energies of biochar combustion were obtained and found to significantly vary with the conversion degree (from about 150 to 250 kJ mol−1 in the range of conversion degree from 0.05 to 0.95).

Effects of biochar application rate on sandy desert soil properties and sorghum growth

The addition of biochar (BC) has been suggested to increase the soil fertility and crop productivity of agricultural lands. This study evaluated the effect of different levels of BC on properties of sandy desert soils and its ultimate impact on plant growth. The samples of desert sand were taken from the Kubuqi of Inner Mongolia, China and the Thar Desert, Pakistan. The sands were treated with a BC made from the fast pyrolysis of pine sawdust at 400°C. Four BC application rates i.e. 0, 15, 22 and 45tha−1 were used in this study. Effects of BC addition on the water consumption and plant growth of sorghum were monitored for eight weeks in a pot experiment. The hydraulic and chemical properties of soil were analyzed to discern the effect of BC on the fertility of sandy desert soils.The results showed that BC amendment significantly improved soil hydraulic and chemical properties. The BC applied at the rate of 22tha−1 provided the best results as compared to all other treatments. Compared with the control group, the soil water-holding capacity (WHC) increased by 11% and 14%, water-retention capacity (WRC) increased by 28% and 32% and hydraulic conductivity decreased by 32% and 7% under the Kubuqi and the Thar Desert soils, respectively when BC was applied at 22tha−1. Similarly, total C increased by 11% and 7%, total K increased by 37% and 42%, total P increased by 70% and 68% and total Ca increased by 69% and 75% while soil pH significantly reduced by 0.67 and 0.79units, in the Kubuqi and the Thar Desert soils, respectively. The sorghum dry matter yield (DMY) was also significantly improved by 18% and 22% under the Kubuqi and the Thar Desert soils, respectively. The higher sorghum DMY consequently improved water-use efficiency (WUE) by 40% and 41% under the Kubuqi and the Thar Desert soils, respectively. In contrast, the plant growth and DMY declined at higher application rate (45tha−1) of BC. The BC made from fast pyrolysis of pine sawdust at a temperature of 400°C showed great potential in improving the quality of sandy desert soils. Hence, it can be used for sandy desert soil management.

Production of Bio-oil from Pine Sawdust by Rapid Pyrolysis in a Fluidized-bed Reactor

This article reports the experimental results of rapid or fast pyrolysis of pine sawdust in a bench-scale plant equipped mainly with a fluidized-bed reactor and a hot vapor filtration unit. The influence of pyrolysis temperature on product distribution was investigated. In each experiment, the mass balance was established and the chemical and physical characteristics of the products were examined. Fast pyrolysis experiments were conducted at a temperature range of 400–500°C using a biomass particle size of 250–425 µm. Results showed that the optimal reaction temperature for bio-oil production was 462°C. The maximum bio-oil yield was approximately 68.4 wt%. The density of bio-oil was found to be 1.2 g/ml. The lower heating value of the bio-oil was 18.2 MJ/kg, while the pH values of the bio-oil were approximately 2.5. The solids and ash contents of bio-oil were 0.3 and 0.01 wt%, respectively.

Product quality and catalyst deactivation in a four day catalytic fast pyrolysis production run

Catalytic fast pyrolysis of pine sawdust was successfully carried out in VTT's 20 kg h−1 Process Development Unit using a spray dried HZSM-5 catalyst. Approximately 250 kg of partially deoxygenated pyrolysis oil was produced over a period of four days. The catalytically produced pyrolysis oil had an average moisture content of 8.3 wt%, and average carbon and oxygen contents of 72.0 and 21.5 wt% on a dry basis, respectively. Approximately 24% of the original biomass carbon was present in the pyrolysis oil, whereas 14% of carbon was in the form of aqueous side products, which totaled approximately 600 kg. The pyrolysis oil contained a high amount of lignin derived water-insoluble material, as well as 6.4 wt% of aromatic hydrocarbons. The majority of the carbohydrate derived products, i.e. acids, aldehydes, ketones and sugar-type compounds, were found in the aqueous product fraction. While the quality of pyrolysis oil remained quite stable during the four day experiment, distinct changes were observed in the properties and the behavior of the catalyst. Coke formation was heaviest at the beginning of the experiment, and then subsided over time. Catalyst micropore area and volume also decreased during the experiment. This transformation was accompanied by apparent changes in the crystallinity and the structure of the catalyst. Scanning electron microscope images of the catalyst also revealed clear physical damage to the particles. Biomass alkali metals also deposited on the catalyst, and the spent catalyst contained a total of 1.1 wt% of Ca, K, Mg and P after the experiment. A linear correlation was observed between catalyst alkali metal content and acidity, which indicated that biomass alkalis substituted the proton functionalities of the HZSM-5 acid sites.

Removal of Tar during Pine Sawdust Fast Pyrolysis with Catalysts

At 600°C, fast pyrolysis of pine sawdust with and without catalysts were investigated in a fixed-bed reactor to determine the effects of five catalysts on the removing tar and changing components of tar. Based on difference of the physical properties and chemical catalytic, five catalysts, including sand, porous silica, activated alumina, fused alumina and zeolite were chosen. The gas chromatography/mass spectrometry (GC/MS) was used to analyze tar compositions. The results showed that the conversion rates of tar: zeolite>activated alumina>fused alumina>porous silica>sand. The physical properties and the chemical catalytic activities of the catalysts were the two main reasons, in which the physical properties of catalysts mainly influenced the contents of aldehydes, hydrocarbons and phenols, while chemical catalytic activities of catalysts mainly influenced the contents of acids, aldehydes, ketones, hydrocarbons and phenols.

Upgrading of the liquid fuel from fast pyrolysis of biomass over MoNi/ γ-Al 2O 3 catalysts

The hydrotreatment of bio-oil, which obtained from fast pyrolysis of pine sawdust, was investigated over MoNi/ γ-Al 2O 3 catalyst under mild conditions (373 K, 3 MPa hydrogen pressure). Acetic acid was taken as a model compound to investigate the effects of Mo promoter contents and reducing temperatures of catalysts on the catalysts activity under the condition of 473 K and 3 MPa hydrogen pressure. X-ray diffraction and temperature programmed reduction showed that the addition of Mo promoter benefited the uniformity of nickel species and inhibited the formation of NiAl 2O 4 spinel in the catalysts. The GC spectrum of liquid products showed the mechanism of the model reaction. The maximum conversion of acetic acid (33.20%) was attained over 0.06MoNi/ γ-Al 2O 3 catalysts being reduced at 873 K. This catalyst was chosen for the upgrading of raw bio-oil. After the upgrading process, the pH value of the bio-oil increased from 2.33 to 2.77. The water content increased from 35.52 wt.% to 41.55 wt.% and the gross calorific value increased from 13.96 MJ/kg to 14.17 MJ/kg. The hydrogen content in the bio-oil increased from 6.25 wt.% to 6.95 wt.%. The product properties of the upgraded bio-oil, particularly the hydrogen content and the acidity were considerably improved. The results of gas chromatography–mass spectrometry analysis showed that both hydrotreatment and esterification had happened over 0.06MoNi/ γ-Al 2O 3 (873) catalyst during the upgrading process.