Non-catalytic Fast Pyrolysis Research Articles

Thermal Reactivity of Bio-Oil Produced from Catalytic Fast Pyrolysis of Biomass.

Catalytic fast pyrolysis (CFP) of biomass is a versatile thermochemical process for producing a biogenic oil that can be further upgraded to sustainable transportation fuels, chemicals, and materials. CFP oil exhibits reduced oxygen content and improved thermal stability compared to noncatalytic fast pyrolysis oil. However, some level of reactive oxygenates remain in CFP oils, and reactions between these species can result in molecular weight growth and increased viscosity, leading to the potential for challenges during transportation, storage, and downstream processing. Previous research has provided considerable insight into the reactivity of noncatalytic fast pyrolysis oils, but CFP oils have yet to be studied in a similar fashion. Consequently, the degree of catalytic upgrading that is necessary to effectively stabilize CFP oils has yet to be established, and little is known about the mechanistic details underlying the process. The current study addresses this knowledge gap by controlling the CFP reaction conditions to systematically vary the oxygen content of the resulting oil. Accelerated thermal reactivity studies were then performed, and the CFP oils were analyzed using gas chromatography-mass spectrometry (GC-MS), Fourier transform ion cyclotron mass spectrometry (FT-ICR MS), gel permeation chromatography (GPC), and viscometry to evaluate the impact of heating on their physical and chemical properties. The results revealed that short chain carbonyls, anhydrosugars, and lignin derivatives with conjugated vinyl groups likely play a role in the thermal reactivity of CFP oils. Additionally, experiments performed across a wide variety of feedstocks revealed relatively low thermal reactivity for CFP oils with oxygen contents of <20 wt %. However, above this threshold value, the thermal reactivity grew exponentially as a function of oxygen content, resulting in large increases in viscosity and molecular weight. These results serve to deepen the mechanistic understanding of CFP oil thermal reactivity and help inform the development of quality specifications for catalytic upgrading to effectively stabilize CFP oils.

Catalytic upcycling of post-consumer multilayered plastic packaging wastes for the selective production of monoaromatic hydrocarbons

In order to obtain extended storage life of food-grade materials and better barrier properties against environmental factors, a multilayer plastic packaging (MLP) is often used. The multilayer packaging plastics are labelled as “other” (SPI#7) category, and are manufactured with a combination of barrier plastics, rigid plastics and printing surface. Owing to their complex composition and difficulty in separating the layers of MLP, its mechanical recycling is challenging. In this study, MLP wastes (MLPWs) were collected from zero-waste garbage collection center of IIT Madras, India, and thoroughly characterized to determine their composition and plastic types. MLPWs were characterized using various physico-chemical methods such as thermogravimetric/differential scanning calorimetric analysis, Fourier transform infrared spectroscopy, bomb calorimetry, and proximate and ultimate analyses. The MLPWs were mainly made up of polyethylene (PE) and polyethylene terephthalate (PET). Further, the non-catalytic and zeolite-catalyzed fast pyrolysis of these MLPWs were studied using analytical pyrolysis coupled with gas chromatograph/mass spectrometer (Py-GC/MS). The non-catalytic fast pyrolysis of MLPWs primarily produced a mixture of aliphatic and alicyclic hydrocarbons, while zeolite catalyzed fast pyrolysis resulted in the formation of mono-aromatic hydrocarbons (MAHs). The activity of HZSM-5, zeolite Y (HY) and zeolite beta (Hβ) catalysts were evaluated, and the salient products were quantified. The yields of MAHs like benzene, toluene, ethylbenzene and xylene using the zeolites followed the trend: HZSM-5 (14.9 wt%) > HY (8.1 wt%) > Hβ (7.8 wt%), at 650 °C. The use of HZSM-5 resulted in highest yield of MAHs, viz. 16.1 wt%, at the optimum temperature of 550 °C and MLPW-to-catalyst ratio of 1:15 (w/w). The superior activity of HZSM-5 is due to its nominal acidity and larger pore size of 4.24 nm, as compared to HY and Hβ. The MAHs yield from three other types of MLPWs varied in the range of 9–16 wt%. The present study demonstrates a promising pathway for the catalytic upcycling of highly heterogeneous MLPWs in the context of circular economy.

Levoglucosenone, furfural and levomannosan from mannan-rich feedstock: A proof-of-principle with ivory nut

This work pioneers the thermocatalytic conversion of tagua seeds (or ivory nut) from the palm Phytelephas aequatorialis into key chemical building blocks, being levoglucosenone, furfural and levomannosan. Annually, ca. 100,000 metric ton of those seeds are produced in Ecuador. Mannan (a mannose-polymer similar to cellulose) is the main constituent in tagua. Thermocatalytic conversions were first explored on analytical scale to see if – and to which extent – e.g., levoglucosenone, was obtained from tagua, using catalysts with proven activity for cellulose conversion, being H3PO4 or ZnCl2. Non-catalytic fast pyrolysis led to levomannosan as main product (33.89 wt% ± 0.24 wt%), much like levoglucosan is the main product from cellulose pyrolysis. Catalytic fast pyrolysis using H3PO4 or ZnCl2 resulted in value-added levoglucosenone (max 6.64 wt% ± 0.27 wt%) and furfural (max 13.17 wt% ± 0.66 wt%) at the expense of levomannosan (between 12 wt.%–14 wt%). Validation experiments with a continuous fast pyrolysis auger reactor were successful and led to pyrolysis liquids with e.g., 3.69 wt% levoglucosenone, using H3PO4-infused ivory nut. Although further optimization should follow this work, the results showcased a fundamental “mannan to levoglucosenone and furfural” conversion and therefore the potential of mannan-rich feedstock for biorefining. Moreover, these results can be translated to other mannan-rich agricultural residues, like açaí seeds, which are a major residue in Brazil (1.1 million metric ton annually).

Aqueous phase of thermo-catalytic reforming of sewage sludge – quantity, quality, and its electrooxidative treatment by a boron-doped diamond electrode

Pyrolysis is a promising conversion technology to produce biofuels from residues such as sewage sludge. In this study, the chemical composition and the amount of the resulting aqueous phase from the thermo-catalytic reforming process of sewage sludge at different process parameters are compared to those of non-catalytic fast pyrolysis processes from literature. Furthermore, electrooxidation using a boron-doped diamond (BDD) electrode was investigated as purification technology for the resulting aqueous phase. The results of this study show that the quantity of the aqueous phase strongly depends on the temperature of the thermo-catalytic reforming process and is presumably governed by the influence of secondary gas-carbonisate reactions like the water gas shift reaction. Higher reaction temperatures result in a reduced amount of the aqueous phase. The chemical composition of the aqueous phase of fast pyrolysis processes was comparable to that obtained at the thermo-catalytic reforming process. To reduce the chemical oxygen demand (COD) and the number of refractory substances to a level at which the aqueous phase can be discharged into a conventional wastewater treatment plant, electrooxidation experiments with the aqueous phase of the thermo-catalytic process were carried out using a BDD electrode. The treatment efficiency was investigated in galvanostatic operation varying the applied current density and the flow rate of the aqueous phase. A COD removal of 94.6% was achieved after 0.54kWh at an instantaneous current efficiency of 0.47 at a current density of 50 mA/cm2 and a flow rate of 3.7 L/min. This indicates that electrooxidation by a BDD electrode can be a promising purification technology for the aqueous phase from pyrolysis of sewage sludge. However, the high energy consumption of the process will need to be addressed in future studies to make the process economically feasible.

Friction and wear properties of biomass-derived oils via thermochemical conversion processes

Tribological properties of biomass-derived oils (bio-oils) were experimentally investigated, and the properties were compared with that of standard mineral oils used for lubrication purposes. Bio-oils were obtained from fast pyrolysis (using poultry and pine), gasification (“gasitar” using pine) and hydrothermal liquefaction processes (using Scenedesmus and Nannocholoropsis). The friction and wear tests were conducted using a ball on the disk tribometer test. The results showed that the coefficient of friction (COF) were around 0.02 for both gasitar and Scenedesmus bio-oil; whereas, catalytic and non-catalytic pyrolysis oils had a COF around 0.1. The wear measurements showed that catalytic fast pyrolysis bio-oils had lower wear followed by non-catalytic bio-oil and “gasitar”. Nannocholoropsis bio-oil had the highest amount of wear, and algal bio-oils showed higher wear compared to other oils. The bio-oil chemical analysis indicated that catalytic and non-catalytic fast pyrolysis bio-oil had higher oxygen content, while algal bio-oil had higher nitrogenates. Gasitar had higher hydrocarbon content with lower oxygen and nitrogenates making it a favorable lubricating oil.

Selective preparation of light aromatic hydrocarbons from catalytic fast pyrolysis vapors of coal tar asphaltene over transition metal ion modified zeolites

The catalytic cracking of coal tar asphaltene (CTA) pyrolysis vapors was carried out over transition metalion modified zeolites to promote the generation of light aromatic hydrocarbons (L-ArHs) in a pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS) micro-reactor system. The effects of ultra stable Y (USY), Co/USY and Mo/USY on the selectivity and yield of L-ArHs products and the extent of deoxygenation ( E deoxygenation ), lightweight ( E lightweight ) from CTA pyrolysis volatiles were investigated. Results showed that the yields of L-ArHs are mainly controlled by the acid sites and specific surface area of the catalysts, while the deoxygenation effect is determined by theirs pore size. The E lightweight of CTA pyrolysis volatiles over USY is 9.65%, while the E deoxygenation of CTA pyrolysis volatiles over Mo/USY reaches 20.85%. Additionally, the modified zeolites (Mo/USY and Co/USY) exhibit better performance than USY on L-ArHs production, owing to the synergistic effect of metal ions (Mo, Co) and acid sites of USY. Compared with the non-catalytic fast pyrolysis of CTA, the total yield of L-ArHs obtained over USY (4032 mg∙kg −1 ), Co/USY (4363 mg∙kg −1 ) and Mo/USY (4953 mg∙kg −1 ) were increased by 27.03%, 38.19% and 54.78%, respectively. Furthermore, the possible catalytic conversion mechanism of transition metal ion (Co and Mo) modified zeolites was proposed based on the distribution of products and the characterizations of catalysts.

Improving hydrocarbons production via catalytic co-pyrolysis of torrefied-biomass with plastics and dual catalytic pyrolysis

To increase the low yield and selectivity of aromatic hydrocarbons during the biomass pyrolysis process, we torrefied the biomass and then co-pyrolyzing with plastics such as high-density polyethylene (HDPE), polystyrene (PS), ethylene–vinyl acetate (EVA) and polypropylene (PP) and also single and dual catalyst layouts were investigated by Py-GC/MS. The results showed that non-catalytic fast pyrolysis (CFP) of raw bagasse (RBG) generated no aromatics. After torrefaction non-CFP of torrefied bagasse (TBG) generated low aromatic yield. Indicating that torrefaction would enhance the proportion of aromatics during the pyrolysis process. The CFP of TBG 200°C and TBG 240°C over ZSM-5 produced the total aromatic yield of 1.96 and 1.88 times higher, respectively, compared to non-CFP of TBG. Furthermore, the addition of plastic could increase H/Ceff ratio of the mixture, consequently, increase the yield of aromatic compounds. Among the various torrefied-bagasse/plastic mixtures, the CFP of TBG/EVA (7:3 ratio) mixture generated the highest the total aromatic yield of 7.7 times more than the CFP of TBG alone. The dual catalyst layout could enhance the yield of aromatics hydrocarbons. The dual-catalytic co-pyrolysis of TBG 200°C /plastic (1:1) ratio over USY (ultra-stable Y zeolite)/ZSM-5, improved the total aromatics yield by 4.33 times more than the catalytic pyrolysis of TBG 200oC alone over ZSM-5 catalyst. The above results showed that the yield and selectivities of light aromatic hydrocarbons can be improved via catalytic co-pyrolysis and dual catalytic co-pyrolysis of torrefied-biomass with plastics.

Catalytic and noncatalytic fast pyrolysis of waste tires to produce high-value monocyclic aromatic hydrocarbons

In this work, catalytic and noncatalytic fast pyrolysis of waste tires were studied in an analytical pyrolyzer coupled with gas chromatography-time-of-flight mass spectrometry to obtain valuable monocyclic aromatic hydrocarbons (MAHs), especially benzene, toluene, ethylbenzene, xylene etc. (BTEX). The various influencing factors such as the heating rate (10−20000 °C/s), atmosphere (He, H2, N2, CH4, O2), temperature (500−800 °C), and time (5−30 s) were explored. The heating rate and temperature had the greatest influence on the distribution of pyrolysis products, where 40.91 % MAHs were obtained at 500 °C/s and 750 °C in helium atmosphere. In the process of catalytic fast pyrolysis, the nine zeolite catalysts were investigated. The Hβ catalyst is conducive to the formation of MAHs (up to 53.09 %), while the content of BTEX was only 9.05 %. The MCM-41Q catalyst is beneficial to the formation of BTEX (22.35 %), as the content of MAHs was 46.09 %.

Hydrocarbon Production from Catalytic Pyrolysis-GC/MS of Sacha Inchi Residues Using SBA-15 Derived from Coal Fly Ash

In this work, Sacha inchi (Plukenetia volubilis L.) residues were used as biomass feedstocks in catalytic upgrading pyrolysis with SBA-15, which is a substance synthesized from coal fly ash (CFA), using alkali fusion, followed by hydrothermal treatment (SBA-15-FA). The catalytic activity of fly ash-derived SBA-15 was investigated through the fast pyrolysis of Sacha inchi residues for upgrading the pyrolysis vapors using the analytical pyrolysis-GC/MS (Py-GC/MS) technique. The pyrolysis temperature was set at 500 °C and held for 30 s while maintaining the Sacha inchi residues to catalyst ratios of 1:0, 1:1, 1:5, and 1:10. In addition, the SBA-15s synthesized from chemical reagent and commercial SBA-15 were evaluated for comparison. The non-catalytic fast pyrolysis of Sacha inchi (SI) mainly consisted of fatty acids (46%), including chiefly linoleic acid (C18:2). Other compounds present were hydrocarbon (26%) and nitrogen-containing compounds (8.7%), esters (9.0%), alcohols (6.4%), and furans (3.6%). The study results suggested that the SBA-15-FA showcased a high ability to improve aliphatic selectivity (mainly C5–C20) and was found to be almost 80% at the biomass to catalyst ratio of 1:5. Moreover, the increase in catalyst contents affected the enhancement of hydrocarbons yields and tended to promote the deoxygenation reaction. Interestingly, the catalytic performance of SBA-15 derived from fly ash could be compared to that of the commercial SBA-15 in terms of producing hydrocarbon compounds as well as reducing oxygenated compounds.

Pilot scale oxidative fast pyrolysis of sawdust in a fluidized bed reactor: A biorefinery approach

Oxidative fast pyrolysis of sawdust was performed in a pilot scale fluidized bed system (3 kg/h) under stabilized experimental conditions (0.20 equivalence ratio and 550 °C). Experiments were performed in non-catalytic and catalytic (ZSM-5) mode. During non-catalytic fast pyrolysis, bio-oil (∼38 wt%), bio-char (∼12 wt%) and pyro-gas (∼50 wt%) were obtained; in contrast, for catalytic fast pyrolysis bio-oil, bio-char and pyro-gas yields were ∼44 wt%, ∼4 wt% and ∼52 wt% respectively. The obtained bio-oil was characterized through CHNSO, NMR (1H and 13C NMR), FT-IR and GC–MS techniques. GC–MS analysis of the bio-oil shows it is a mixture of ∼21 chemical compounds. Furthermore, NMR (1H and 13C NMR) and FT-IR results indicates presence of hydrocarbon, alcohol, phenol and aldehyde in the bio-oil. The TGA of bio-char shows that it is stable up to 950 °C. The activation energies (Ea) of sawdust and bio-char are found to be 112.3 kJ/mol and 46.92 kJ/mol respectively. FT-IR analysis of bio-char clearly revealed removal of functionalized organic compounds during devolatilization of sawdust. In addition, GC analysis of pyro-gas suggests that it is a mixture of N2 (35.55 vol%), CO (34.49 vol%), CO2 (16.80 vol%), H2 (4.54 vol%), O2 (4.25 vol%), and CH4 (4.41 vol%).

Kinetic analysis and catalytic pyrolysis of spent medicinal herb over HZSM-5 and HY

In this study, the kinetic analysis on the pyrolysis of a spent medicinal herb, namely spent Achyranthes root, is performed using a thermogravimetric analyzer and a model-free kinetic analysis method, allowing the calculation of activation energy values without the assumption of kinetic model. Owing to the structural change of lignin and elimination of hemicellulose during the decoction of raw Achyranthes root, the thermogravimetric analysis results show a large difference between the derivative thermogravimetry curves of spent and raw Achyranthes roots. The average apparent activation energy value of spent Achyranthes root, obtained from the non-isothermal thermogravimetric analysis, are found to be lower than those of raw Achyranthes root. This comes as a result of the much lower content of hemicellulose in spent Achyranthes root caused by the hemicellulose elimination from raw Achyranthes root during the decoction process. The catalytic fast pyrolysis of spent Achyranthes root over HZSM5-30 (HZSM-5 with SiO2/Al2O3 = 30) and HY30 (HY with SiO2/Al2O3 = 30) was performed using a two-stage fixed-bed reactor system. The catalytic fast pyrolysis of spent Achyranthes root over both HY30 and HZSM5-30 produced the much larger amount of aromatic hydrocarbons, compared to the non-catalytic fast pyrolysis, with a parallel decrease of oxygen-containing pyrolyzates. Owing to its robust pore structure and high acidity, it was the HZSM5-30 that produced the highest quality oil during the catalytic fast pyrolysis of spent Achyranthes root, having higher selectivity of mono-aromatic hydrocarbons compared to HY30.

Catalytic and noncatalytic fast pyrolysis of Jatropha seeds: Experimental measurements and modeling

The main problems facing worldwide especially the developing countries are the shortage and high prices of fossil fuels, therefore, searching for renewable sources of energy is highly recommended. Therefore, the conversion of biomass into alternative fuel has become one of the attracting sources of renewable energy. The bio-energy is now accepted as having the potential to provide the major part of the projected renewable energy in the future. However, there are many conversion processes such as pyrolysis, gasification, combustion, and liquefaction. Among them the thermochemical conversion (pyrolysis) which acquired special attention as it can convert it directly into liquid, solid and gaseous products by thermal decomposition in absence of oxygen. The present work will consider Jatropha curcas as the biomass source because Jatropha seeds are high energy bearing seeds available in nature. The aim of this work is to examine the fast pyrolysis process of Jatropha seeds with and without catalyst. Further, a model has been tested using experimental data measured in this study. The thermal decomposition of the Jatropha seed and the kinetics of the fast pyrolysis behavior has been investigated in the two cases using thermogravimetric analysis (TGA) at a heating rate of 20ᵒC/min in air atmosphere which indicated the range of temperature in which rate of decomposition is maximum. The results of TGA and DTG data revealed that iso-conversational free model (KAS) method gave excellent prediction with a good agreement of oil yields. The activation energies of Jatropha curcas seeds were obtained in the range of (60 to 65 kJ/mol-1) which was much lower than that of the literature (196 to 222 kJ/mol-1) concluding that the reaction rate was fast as a fast pyrolysis process already used and the correlation coefficient (R2) is 0.9987.

Co-processing of wood and wheat straw derived pyrolysis oils with FCC feed—Product distribution and effect of deoxygenation

The behavior of bio-oils when co-processed with conventional fossil feed in a fluid catalytic cracking (FCC) unit is suitably tested using a microactivity testing unit (MAT). In the present study, non-catalytic fast pyrolysis oils originating from wood and wheat straw were co-processed in a MAT at a 20/80 weight blend (bio-oil/FCC feed). In addition, bio-oil obtained from deoxygenating the straw derived vapors over a steamed HZSM-5/Al2O3 extrudate catalyst was tested. The bio-oils were characterized for elemental composition and moisture content to calculate energy recoveries, amounting to 35% and 30% for the non-catalytically obtained wood and straw oils, while it was 19% for the partly deoxygenated straw oil. Wood oil showed higher acidity (61 mg KOH/g) and molar O/C ratio (0.35) compared to straw oil (54 mg KOH/g and O/C = 0.24). The acidity and O/C ratio was reduced for the straw-derived bio-oil from catalytic vapor treatment (3 mg KOH/g, O/C = 0.08). At constant conversion (77.5%) at the MAT, the wood pyrolysis oil showed a product distribution quite similar to the reference oil while the wheat straw pyrolysis oil gave a 1.6% points higher coke yield and a 1.2% points lower liquid petroleum gas (LPG) yield. For the catalytically treated wheat straw pyrolysis oil, an even higher coke yield (2.6% points) and 1.9% points lower LPG yield resulted. The observations are attributed to the higher content of aromatics, phenolics, and nitrogen containing compounds of the catalytically upgraded straw fast pyrolysis oil.

STEAM REFORMING OF UPGRADED BIO-OIL AQUEOUS PHASE FRACTION FROM SUNFLOWER SEED HULLS: THERMODYNAMIC ANALYSIS

This work focuses on the study of hydrogen production process departing from waste lignocellulosic biomass. The bio-oil was first obtained by non-catalytic fast pyrolysis of sunflower seed hulls. Subsequently, it was upgraded to reduce the concentration of higher molecular weight compounds by water addition and mixing. A 1/1 bio-oil:water ratio was selected here. Later, a thermodynamic analysis based on free energy minimization was profited to study the steam reforming process of the upgraded bio-oil sample. The influence of the operation temperature on the reforming was analyzed. The highest hydrogen yields were obtained at ~740°C. A comparison with acetic acid used as model compound of the bio-oil is included. Results show that acetic acid is not a good approximation of a real aqueous phase of upgraded bio oil fraction. The study concludes with an analysis on the energetic efficiency, showing that its maximum is presented at lower temperatures than the maximum yield, due to the thermal requirements of preheating.

Uncertainty estimation approach in catalytic fast pyrolysis of rice husk: Thermal degradation, kinetic and thermodynamic parameters study

The aim of this study was to understand the influence of catalyst in thermal degradation behavior of rice husk (RH) in catalytic fast pyrolysis (CFP) process. An iso-conversional Kissinger kinetic model was introduced into this study to understand the activation energy (EA), pre-exponential value (A), Enthalpy (ΔH), Entropy (ΔS) and Gibb’s energy (ΔG) of non-catalytic fast pyrolysis (NCFP) and CFP of RH. The study revealed that the addition of natural zeolite catalyst enhanced the rate of devolatilization and decomposition of RH associated with lowest EA value (153.10 kJ/mol) compared to other NCFP and CFP using nickel catalyst. Lastly, an uncertainty estimation was applied on the best fit non-linear regression model (MNLR) to identify the explanatory variables. The finding showed that it had the highest probability to obtain 73.8–74.0% mass loss in CFP of rice husk using natural zeolite catalyst.

In situ catalytic pyrolysis of Jatropha wastes using ZSM-5 from hydrothermal alkaline fusion of fly ash

In this work, ZSM-5 catalysts was successfully synthesized from fly ash via alkali fusion followed by hydrothermal treatment with the initial SiO2/Al2O3 ratios of 24 and 40 (HZSM5-FA). HZSM-5 synthesized with SiO2/Al2O3 ratios of 40 exhibited superior physical and textural properties such as higher crystallinity, larger surface area, and smaller particle size. After synthesis, the catalytic activity of HZSM5-FA with SiO2/Al2O3 ratios of 40 was investigated via fast pyrolysis of Jatropha wastes in order to upgrade the evolved vapor using Py-GC/MS technique. In addition, the ZSM-5 prepared from chemical reagents (HZSM5-CV) were evaluated for comparison. The pyrolysis temperature was set at 500 °C with the Jatropha wastes to catalyst ratio of 1:1–1:10. The major components from non-catalytic fast pyrolysis were acids (51%) and nitrogen containing compounds (20%). Other organic compounds were ketones, alcohols, esters, ethers, phenols and sugars. The presence of HZSM5-FA contributed to the elimination of undesirable oxygenated compounds such as fatty acids which could mitigate problem regarding acidity and instability in bio-oil. In addition, this synthesized material also remarkably improved the hydrocarbon selectivity, especially aromatic hydrocarbons. Higher catalyst contents had positive effect on the formation of aromatic hydrocarbons and tended to promote deoxygenation and denitrogenation. At high catalyst proportion (biomass to catalyst ratio of 1:10), HZSM5-FA produced the highest hydrocarbon selectivity of 97%, mainly benzene, toluene and xylene (BTX), which are valuable products due to their high heating values. Interestingly, the catalytic activity of HZSM5-FA was comparable to that of the HZSM5-CV in terms of reducing oxygenates as well as nitrogenous compounds and consequently increasing hydrocarbon compounds. Overall, HZSM-5 derived from fly ash can be economically used as a potential catalyst for pyrolysis oil upgrading applications.

Hydrotreating of Model Mixtures and Catalytic Fast Pyrolysis Oils over Pd/C

Noble metal catalysts may be attractive for hydrotreating of catalytic fast pyrolysis (CFP) oils. Model mixtures of raw noncatalytic fast pyrolysis and CFP oils representative of upgrading over HZSM-5 were hydrotreated in a batch reactor at 250–360 °C with palladium/carbon catalyst and 100 bar (cold) of hydrogen. The CFP oils gave high carbon yields of >95%, consumed less hydrogen per gram of oil produced, and had lower final oxygen concentrations than the raw oils did. GC/MS results were consistent with hydrogenation of alkenes and some oxygen-functionalized aromatic rings (e.g., phenolics) followed by hydrodeoxygenation at 360 °C. Complete deoxygenation was not obtained, and higher temperatures are recommended. The model oils’ chemical transformations, carbon yields, and deoxygenation were similar to those of oils produced in a bench-scale reactor with HZSM-5 catalyst.

Non-catalytic fast pyrolysis and catalytic fast pyrolysis of Nannochloropsis oculata using Co-Mo/γ-Al2O3 catalyst for valuable chemicals

Microalgae is projected as a promising third generation biomass feedstock for the production of biofuel and fine chemical intermediates. This study is focused on the selective production of chemicals from Nannochloropsis oculata microalga via catalytic fast pyrolysis technique using Co-Mo/γ-Al2O3 catalyst. Non-catalytic and catalytic fast pyrolysis (CFP) experiments were conducted in an analytical micropyrolyzer coupled with gas chromatograph/mass spectrometer to study the effects of temperature, catalyst-to-algae ratio, and metal loading on support on pyrolysate composition. The catalyst, Co-Mo/γ-Al2O3, was prepared using wetness incipient impregnation method, and characterized for its structure and pore size distribution. Catalyst-to-algae mass ratios used to study the pyrolysate composition and quality were 1:3, 1:1 and 2:1. The major organic compounds from both non-catalytic fast pyrolysis and CFP of the microalga were long chain nitriles, long chain alkanes and alkenes, polyaromatic and monoaromatic hydrocarbons. The optimum fast pyrolysis temperature under non-catalytic conditions that promoted the selectivity of aliphatic and aromatic hydrocarbons was 500 °C. The incorporation of Co-Mo/γ-Al2O3 catalyst promoted the formation of specific organic compounds like 1‑isocyanobutane and dimethylketene to the tune of 35% selectivity. The formation pathways for these compounds are proposed to involve dehydration, isomerization, ketonization and CH addition reactions of the amide and carboxylic acid moieties generated from the protein and lipid fractions of the alga. Owing to the low oxygen content in the pyrolysates from CFP, the estimated calorific value of organics in the pyrolysates was higher (33–39 MJ kg−1) than that of the microalga (18 MJ kg−1).

Biomass catalytic fast pyrolysis over hierarchical ZSM-5 and Beta zeolites modified with Mg and Zn oxides

Hierarchical ZSM-5 and Beta zeolites, loaded with MgO and ZnO, have been explored for the catalytic fast-pyrolysis of eucalyptus woodchips. These materials exhibit a high dispersion of the MgO or ZnO phases, which is probably due to the presence of a hierarchical porosity with both micro- and mesopores in the zeolitic supports. The incorporation of these metal oxides led to a significant reduction in the textural properties and to changes in the acidic properties of the parent zeolites. Thus, a decrease in the concentration of Bronsted acid sites was observed, which was accompanied by the generation of additional Lewis acid sites with medium strength. In addition, the incorporation of metal oxide promotes the formation of significant amount of basic sites, especially for the samples loaded with MgO. Catalytic fast pyrolysis experiments of eucalyptus woodchips were performed in a fixed bed reactor at 500 °C and atmospheric pressure under a nitrogen flow. In comparison with non-catalytic fast pyrolysis, the use of zeolitic catalysts caused a decrease in the bio-oil* (water free basis bio-oil) production due to enhanced formation of gases, as well as coke deposition on the catalyst. However, the quality of the bio-oil* was enhanced since the catalysts were able to decrease its oxygen content. In this way, h-ZSM-5-based catalysts showed a clearly deeper deoxygenation degree compared to those having h-Beta as support, with very low content of anhydro sugars and the formation of a significant amount of aromatics. Regarding the effect of the metal oxide phase, MgO-loaded samples provided bio-oil* with enhanced energy yields and lower oxygen content, probably due to the adequate balance of Lewis acid and basic sites. Likewise, significant differences were observed among the catalysts regarding the deoxygenation pathways and the compounds families present in the bio-oil*.

Comparative Study on Catalytic and Non-Catalytic Pyrolysis of Olive Mill Solid Wastes

In this study, catalytic and non-catalytic fast pyrolysis of dried olive husk and olive kernels was carried out. A bubbling fluidised bed reactor was used for the non-catalytic processing of the solid olive wastes. In-situ catalytic upgrading of biomass fast pyrolysis vapours was performed in a fixed bed bench-scale reactor at 500 °C, for catalyst screening purposes. A maximum bio-oil yield of 47.35 wt.% (on dry biomass) was obtained from non-catalytic fast pyrolysis at a reaction temperature of 450 °C, while the bio-oil yield was decreased at 37.14 wt.% when the temperature was increased to 500 °C. In the case of the fixed bed unit tests, the highest liquid (52.66 wt.%) and organics (30.99 wt.%) yield was achieved with the use of the non-catalytic silica sand. Depending on the catalytic material, the liquid yield ranged from 47.03 to 43.96 wt.% the organic yield from 21.15 to 16.34 wt.% on dry biomass. Solid products were increased from 28.23 wt.% for the non-catalytic run to 32.81 wt.% on dry biomass, when MgO (5% Co) was used.