Catalytic Microwave Pyrolysis Research Articles

HZSM-5 supported with N-doped Fe for microwave catalytic pyrolysis of lignin

Microwave catalytic pyrolysis of lignin is one of emerging technologies for efficiently converting lignin into fuels and chemicals. Molecular sieves (HZSM-5) are widely used as carriers to load metallic components for biomass pyrolysis but often encounter challenges such as high diffusion resistance and insufficient acidity of acidic sites. Traditionally, HZSM-5 is directly modified to enhance the activity of the acidic sites, but this modification is ineffective in improving the metallic components’ activity. Instead, we made nitrogen doping on Fe and then supported on HZSM-5 to construct Fe-N25/HZSM-5 catalysts for microwave catalytic pyrolysis of lignin. The N-doped Fe has the effect of “killing two birds with one stone” on enhancing the catalytic activity. The characterization results indicated that N replaced C of the graphitic carbon network to form carbon nitride structure, and further combined with Fe to generate Fe-N bonds, improving the electronegativity of the metallic component. Besides, the loading of N-doped Fe increased the acidity of the catalyst. The utilization of 1.00Fe-N25/HZSM-5 obtained the greatest bio-gas yield (35.2 wt%), a hydrogen yield of 27.8 mL/min, bio-oil yield (36.4 wt%) and phenol selectivity of 46.2 %. The likely pathway of microwave catalytic pyrolysis on Fe-N25/HZSM-5 was proposed through DFT calculation, using guaiacol as a model compound. The results suggested that N-doped Fe on HZSM-5 8 T tended to break the side-chain methoxy during pyrolysis of guaiacol, with energy barrier of 0.14 eV. This paper provides a promising strategy for modification of microwave pyrolysis catalysts.

Experimental Study on Optimizing Hydrogen Production from Sludge by Microwave Catalytic Pyrolysis Using Response Surface Methodology.

Catalytic pyrolysis technology is a harmless and useful solid waste treatment method. Studying the catalytic pyrolysis of sludge for hydrogen production is of practical significance. Therefore, this paper prepared a bifunctional catalyst with both microwave absorption and catalytic properties from electroplating sludge through carbonization and acid modification processes and then was characterized by XRD, BET, SEM, XPS, and FTIR. An experimental study employed a conventional-then-microwave pyrolysis method to investigate the catalytic pyrolysis process of municipal sludge. Combining central composite design (CCD) and response surface methodology (RSM) with three factors and five levels, this paper investigated the interactive effects of the conventional pyrolysis temperature, microwave irradiation time, and catalyst addition ratio on the unit hydrogen production (UHP) of sludge. A predictive model based on a second-order polynomial regression equation was developed. The results revealed that the catalyst possesses a specific surface area and pore structure and that the second-order polynomial model fits well. The conventional pyrolysis temperature, microwave irradiation time, catalyst addition ratio, and interaction between the latter two significantly affected the UHP of sludge. The optimal operation conditions of conventional pyrolysis temperature, microwave irradiation time, and catalyst addition ratio were 462.7 °C, 8.8 min, and 12.4%, respectively. Under these optimal conditions, the UHP was 13.22 mmol/g, with a relative error of only 1.12% compared to the predicted model value of 13.37 mmol/g.

Anaerobic Digestion of Food Waste with the Addition of Biochar Derived from Microwave Catalytic Pyrolysis of Solid Digestate

This study explores the potential of biochar derived from microwave-assisted catalytic pyrolysis of solid digestate as an additive to enhance the stability and performance of the anaerobic digestion process. The focus was placed on the effects of biochar dosage, pyrolysis temperature, and pyrolysis catalyst on methane production. Biochemical methane potential (BMP) tests using synthetic food waste as the substrate revealed a dosage-dependent relationship with specific methane yield (SMY). At a low biochar dosage of 0.1 g/g total solids (TS), improvement in methane (CH4) production was marginal, whereas a high dosage of 0.6 g/g TS increased CH4 content by at least 10% and improved yield by 35–52%. ANOVA analysis indicated that biochar dosage level significantly influenced CH4 yield, while pyrolysis temperature (400 °C vs. 500 °C) and catalyst (20 wt% K3PO4 vs. 10 wt% K3PO4/10 wt% clinoptilolite) did not lead to significant differences in CH4 yield between the treatments. Correlation analysis results suggested that biochar’s most impactful properties on methane yield would be dosage-adjusted specific surface area (or total surface area per unit volume of substrate) and aromaticity index. The findings underscore the potential of solid-digestate-derived biochar as a beneficial additive for anaerobic digestion and hence the sustainability of food waste management system.

Microwave catalytic pyrolysis of solid digestate for high quality bio-oil and biochar

Microwave-assisted catalytic pyrolysis (MACP) of solid digestate (SD) into value-added products presents a promising solution for waste SD. Both types of catalysts and reactor temperature critically influence the properties of MACP products. This study systematically investigated pyrolysis of SD mixed with different catalysts (K3PO4, natural zeolite, and mixture of K3PO4 and natural zeolite) at various pyrolysis temperatures (300, 400, and 500 ℃) for bio-oil and biochar production. The results showed that higher temperatures led to reduced bio-oil and biochar yields, favoring gas production. The bio-oil derived from SD with 20 wt% K3PO4 and 20 wt% natural zeolite at 500 ℃ exhibited the largest fraction of aromatic hydrocarbons, reaching 92.43 % and 91.56 %, respectively. Catalytic pyroysis resulted in reduction in bio-oil acidity. Biochar specific surface area is influenced by both heating rate and temperature, with the highest surface area (207 m2/g), pore volume (0.2244 cm³/g), and a more regular pore structure being obtained at 500 ℃ and 66.1 °C/min with 20 wt% K3PO4. This work demonstrated the feasibility of upgrading waste SD into value-added chemicals, materials, and energy-rich fuels by MACP. Notably, SD with 20 wt% K3PO4 at 500 ℃ represents the optimal operating condition for both bio-oil and biochar production.

Catalytic Microwave Pyrolysis of Albizia Branches Using Iraqi Bentonite Clays

Catalytic microwave-assisted pyrolysis of biomass is gaining popularity as an alternative to fossil fuels due to health, environmental, climate, and economic issues. This study conducted a catalytic pyrolysis process of the Albizia plant's branches using an Iraqi clay catalyst (bentonite) focusing on the variables including the biomass-particle size, experimental time, microwave power level, and the catalyst-to-biomass ratio. The physical and chemical properties of the resulting biofuel were analyzed presented by HHV, acidity, density, viscosity, GC-MS, FTIR for bio-oil and SEM, EDX, BET, HHV, FTIR for biochar. The study revealed that addition of bentonite as a catalyst led to enhanced production of biogas produced from 5% to 45% and decreased the power level used from 700 W to 450 W. Also, it raised the production of bio-oil generated with less power level and duration time. The addition of catalyst also affected the characteristics of bio-oil produced such as reducing the acidity by increasing its pH from 5 to 5.7, lowering the viscosity from 4.8 to 3.3 cSt, and the density from 1045 to 1039.2 kg/m3. Adding catalyst increased the percentage of aromatic and alcoholic substances in the bio-oil which led to improve the calorific value from 19.5 to 23 MJ/kg. Additionally, the biochar properties also improved, where the surface area and pore volume increased from 0.5512 to 40.384 m2/g and 0.00011 to 0.0361cm3/g respectively. The higher heating value was raised from 23.5 to 25 MJ/kg also. CH4 is also increased from 3.6 to 8.6% which is one of the essential fuel gasses.

Investigation of products characteristics from microwave catalytic pyrolysis of furfural residue based on the effects of Fe/Mn modified biochar

In this paper, the effect of MnCl2 and FeCl3 modified biochar catalysts on the catalytic pyrolysis products of furfural residue (FR) under microwave field was investigated. The results showed that the highest content in the pyrolysis gas obtained from microwave catalytic pyrolysis (MCP) with modified biochar catalysts was CO, while phenols were found in bio-oil. After metal loading, the specific surface area of the catalyst decreased significantly. The CO production was promoted by microwave pyrolysis of FR over modified biochar catalyst, and MFRC gain was more obvious. The content of H2 all continued to increase with increasing mass of loaded metals, and the opposite was true for CO. The highest relative content of phenols in the bio-oils of FFRC and MFRC were 66.76 % for 2FFRC and 63.66 % for 4MFRC, where the relative content of phenols was 15.50 % and 19.27 %, respectively. The production of sugars and ketones was also promoted by Fe and Mn. The lower loading of active metals significantly promoted the conversion of pyrolysis vapors to phenols while releasing more CO. A possible mechanism of MCP of FR was proposed. The results showed that Fe/Mn-modified char-based catalysts could effectively modulate the composition of bio-oil.

Microwave catalytic pyrolysis of heavy oil: A lump kinetic study approach

Managing heavy oil (HO) has become a vital issue in terms of environmental considerations. Microwave pyrolysis of HO is one of the efficient methods of upgrading and recycling this complex material. In this work, microwave catalytic pyrolysis (MCP) of HO was explored by investigating the effect of heating time (2–10 minutes) and temperature (460–730ºC) on the product yield and quality. The most critical point of this study was utilizing a unique design of SiC foam@HZSM-5 as a microwave absorber and catalyst simultaneously. This special design could eliminate the main problem of previous studies: the unwanted temperature gradient inside the reactor, which was misleading the prediction of kinetic parameters by recording the wrong temperature. The yield of each product’s category from the MCP process was reconstructed through a biharmonic spline interpolation (BSI) algorithm to visualize the simultaneous effect of the heating time and temperature on the yield. The optimum temperature for the MCP process was about 600ºC and a heating time of 6 minutes, which yielded the most valuable hydrocarbons in liquid and gas products. The produced liquid oil and non-condensable gases were analyzed through GC-MS and the collected results were categorized based on the properties of the detected compounds. An eight-lump kinetic model was then proposed based on that categorization. The calculated pre-exponential factors (k0) were higher than the expected values, while the apparent activation energies (Ea) were considerably lower than the reported data in the literature, which was due to the non-thermal and thermal effects of microwave irradiation on the reaction mechanism. The validation of the proposed model indicated the capability of this model to predict reliable data under these conditions.

Comparative microwave catalytic pyrolysis of cellulose and lignin in nitrogen and carbon dioxide atmospheres

In this paper, a cleaner pyrolysis strategy combining microwave heating, catalyst and carbon dioxide was explored for converting biomass components into higher quality products. Catalytic pyrolysis was more favorable for the decomposition and conversion of complex biomass structures. For furfural residue pyrolysis, potassium sulfate contained in sample served as the main catalytic component. Potassium sulfate promoted the increase of phenols in bio-oil. Notably, carbon dioxide atmosphere promoted the decomposition of substances and exerted a significant effect on biomass pyrolysis, which increased bio-oil yield and declined gas yield. When the pyrolysis atmosphere was changed from nitrogen to carbon dioxide, the ID/IG ratio decreased from 1.07 to 0.74, indicating that carbon dioxide decreased defect structure in biochar. Carbon dioxide enriched the porous structure and surface roughness of biochar. Also, carbon dioxide as a carrier gas was found to be more effective than nitrogen in improving the heating values of biochar and the acidity of bio-oil under carbon dioxide was lower than that under nitrogen, which was conducive to the subsequent utilization of biochar and bio-oil. Carbon dioxide promoted the production of alcohols, alkenes, and alkanes in bio-oil. Beneficially, the interaction of cellulose and lignin inhibited the release of hydrogen chloride. At last, this study also provides insights into the mechanism of catalyst and CO2 on biomass microwave pyrolysis.

Production of combustible fuels and carbon nanotubes from plastic wastes using an in-situ catalytic microwave pyrolysis process

This study performed in-situ microwave pyrolysis of plastic waste into hydrogen, liquid fuel and carbon nanotubes in the presence of Zeolite Socony Mobil ZSM-5 catalyst. In the presented microwave pyrolysis of plastics, activated carbon was used as a heat susceptor. The microwave power of 1 kW was employed to decompose high-density polyethylene (HDPE) and polypropylene (PP) wastes at moderate temperatures of 400–450 °C. The effect of plastic composition, catalyst loading and plastic type on liquid, gas and solid carbon products was quantified. This in-situ CMP reaction resulted in heavy hydrocarbons, hydrogen gas and carbon nanotubes as a solid residue. A relatively better hydrogen yield of 129.6 mmol/g as a green fuel was possible in this process. FTIR and gas chromatography analysis revealed that liquid product consisted of C13+ fraction hydrocarbons, such as alkanes, alkanes, and aromatics. TEM micrographs showed tubular-like structural morphology of the solid residue, which was identified as carbon nanotubes (CNTs) during X-ray diffraction analysis. The outer diameter of CNTs ranged from 30 to 93 nm from HDPE, 25–93 nm from PP and 30–54 nm for HDPE-PP mixure. The presented CMP process took just 2–4 min to completely pyrolyze the plastic feedstock into valuable products, leaving no polymeric residue.

High quality products from microwave catalytic pyrolysis of heavy oil and polyethylene

Heavy hydrocarbon residue management has always been an environmental issue; thus, it is essential to find a method for upgrading heavy oils and plastic waste to high quality products as an alternative source of chemicals and fuels. In this study, the microwave catalytic pyrolysis (MCP) of heavy oil (HO) and LDPE (as plastic source) was proposed by employing a unique design of the catalyst, SiC foam@HZSM-5. This special catalyst design provided sufficient mass and heat transfer and enhanced the available catalyst surface area during the pyrolysis process. The effect of microwave power and the HO:LDPE ratio were investigated to optimize the product yield and quality. The results showed that the hazardous and unwanted elements of HO were eliminated by adding LDPE to the feedstock. More importantly, it was observed that the secondary and side reactions were accelerated due to a positive synergistic effect (ΔY), which occurred because of hydrogen donors from the LDPE degradation and the non-thermal effect of microwave heating. The HO:LDPE ratio of 1:1 with a microwave power of 800 W and 10 min heating time were the optimum conditions; the liquid yield was about 42 wt% with around 90% of aromatics (mono- and polycyclic) relative concentration. Furthermore, the proportion of BTX was about 82% of the liquid oil, while the concentration of oxygenated and nitrogenated compounds was less than 2%. Under the above conditions, the proportion of collected non-condensable gases was around 46 wt%, which comprised light olefins (C1-C6) at about 37%, and a considerable proportion of H2 as well. Additionally, adding more LDPE to the feedstock decreased solid residue by promoting the conversion of HO, which improved catalyst efficiency.

Study on high-value products of waste plastics from microwave catalytic pyrolysis: Construction and performance evaluation of advanced microwave absorption-catalytic bifunctional catalysts

A series of bifunctional catalysts (Fe-Ni/SiC) with microwave absorption and catalytic abilities were constructed to realize high-value application of waste plastics by microwave catalytic pyrolysis. The bifunctional performances and mechanisms were explored by a new microwave thermogravimetric oven. The bifunctional catalysts had good pore structure and the active components of Fe2O3, NiO, and NiFe2O4, which made the catalysts with good dielectric and catalytic performances. After catalysis, the heating rates and weight loss rates of low-density polyethylene were 68.18–73.39 °C·min−1 and 0.59–0.68 g·min−1, respectively. The increase in heating rate helped to promote the pyrolysis degree, advance the pyrolysis endpoint, and reduce the energy consumption (11.54 MJ/kg at most). When the catalyst was Fe-Ni/SiC (2:1), the highest gas yield (73.61 wt%) and H2 content (73.89 vol%) was obtained. Moreover, the higher graphitization degree of carbon nanotubes was obtained with more Fe loading. The oriented production of high-value products could be realized by adjusting the type and proportion of active components in the catalyst.

Sustainable valorization of waste keyboard keys via microwave assisted pyrolysis over Fe-Ni doped green catalyst towards clean fuel production

ABSTRACT The technological evolution of electronic equipment in the field of computers and household appliances, along with shorter life of most items, is creating a great concern for managing this waste stream. The main aim of the present investigation was to convert waste keyboard keys into high-quality pyrolysis oil using a microwave catalytic pyrolysis process. Iron (Fe), Nickel (Ni), were doped in different ratios on Biochar (BC) by wet impregnation method, and it was used as a green catalyst for clean fuel production. Initially, a non-catalytic pyrolysis process was conducted and found a maximum pyrolysis oil yield of 49.6 wt.%. Further, microwave catalytic pyrolysis was conducted with variable amount of metal loading and found that highest oil yield of 61.33 wt.% was achieved using 15%Fe-5%Ni/BC catalyst due to the presence of a higher quantity of iron. The produced pyrolysis oil at this condition consists of 45.07% single-ring compounds and reduced the undesirable polycyclic aromatic hydrocarbons (PAHs) in the pyrolysis oil. This work provides a pathway for preparing green catalysts and safe disposal of electrical and electronic plastic waste with better resource recovery.

Insight into product characteristics from microwave co-pyrolysis of low-rank coal and corncob: Unraveling the effects of metal catalysts

Microwave pyrolysis of low-rank coal can provide high yield and quality of valuable products. Coupling with hydrogenated and catalytic pyrolysis is considered to achieve the selective or targeted generation of pyrolysis products. In this study, three metal catalysts KCl, Fe2O3, and CaO were used in the microwave catalytic co-pyrolysis of low-rank coal and corncob to investigate their effects on the temperature rise, product distribution, and product structure characteristics. The results showed that the maximum and final temperatures of microwave co-pyrolysis with the addition of a metal catalyst increased, and the corresponding yield and quality of tar were considerably improved. The porous structure of the char with the added metal catalyst was significantly enhanced, and the carbon microcrystal structure became significantly strong, but the change in thickness was minimal. The formation of aliphatic hydrocarbons and CO functional groups in both char and tar was inhibited when Fe2O3 and CaO were added. Among the three metal catalysts, CaO had the most obvious effect on the pyrolysis products, resulting in a maximum tar yield of 10.89 % and the highest light oil of 17.20 %. The char had a more regular and integrated porous structure; its Aar/Aal ratio reached a maximum of 12.603, showing the highest aromaticity. In addition, the total of valuable gas component and heat value of the pyrolysis gas arrived at 84.81 vol% and 14.93 MJ/m3, which showed excellent yield and performance. This work provides sufficient evidences for clean and efficient utilization of low-rank coal using catalytic microwave pyrolysis technology.

ReaxFF MD simulation of microwave catalytic pyrolysis of polypropylene over Fe catalyst for hydrogen

Microwave-assisted catalytic pyrolysis of waste plastics is promising for hydrogen generation. To study the mechanism of microwave in Fe catalyzed pyrolysis of plastics. Molecular dynamics (MD) simulation was carried out using the ReaxFF method to compare the bonded and non-bonded interatomic interactions at the same temperature under conventional heating and microwave heating at different powers. The results show that the microwave improves the adsorption capacity of Fe clusters, reduces the dissociation energy of CH bonds, and promotes the cleavage of CC bonds due to H radicals at low temperature. Therefore, microwave enhances the generation of H2, reduces the required reaction temperature, and suppresses the generation of small gaseous hydrocarbon molecules and tar. These results prove the reliability of ReaxFF MD and provide a theoretical basis for valorising waste plastics aided by microwave.

Ex-situ catalytic microwave pyrolysis of alkali lignin facilitates the production of monophenols and monoaromatics under the application of LaFe1-xCuxO3 perovskites

Two perovskites, LaFe1-xCuxO3 (x = 0, 0.20), were synthesized by co-precipitation approach, are applied for the ex-situ catalytic pyrolysis of alkali lignin (AL) under microwave-assisted. The results showed that the as-constructed LaFe1-xCuxO3 perovskites exhibited excellent activity towards the production of monophenols and monoaromatics compared with non-catalysis. Especially, after Cu doping exerted stronger deoxygenation effect in comparison to LaFeO3, which was more conducive to forming monocyclic aromatic hydrocarbons (MAHs) with a selectivity of 21.11 %. Interestingly, although the oxygen vacancy concentration in LaCu0.2Fe0.8O3 was higher than that in LaFeO3, the activity of the former towards monophenols (78.72 % selectivity) was basically the same as the latter (79.08 % selectivity), which was associated with their approximately equal surface area, manifesting that the surface area of LaFe1-xCuxO3 perovskites played a more dominant role in ex-situ catalytic pyrolysis of AL relative to oxygen vacancy. Furthermore, air-TG results declared the LaFe1-xCuxO3 catalysts possessed good anti-coking performance (coke amount ∼ 5 %). Notably, the presence of oxygen vacancy (Fe3+-□-Fe2+) in LaFeO3 while Cu doping resulted in forming Cu2+-□-Cu+, which were responsible for combining with oxygenated volatiles to yield the active sites FeOx and CuOx respectively, dominating the ex-situ catalytic pyrolysis of AL.

Dual function intensified cracking of waste engine oil to produce alkane-rich oil: Study on the synergistic effect of Fe-Co/MCM41 catalyst and microwave

In order to use microwave catalytic pyrolysis technology to recover hydrocarbon-rich fuel from waste engine oil, a microwave-driven metal Fe and Co modified MCM41 molecular sieve catalyst was constructed, which solves the defects of the MCM41 of high coking rate, easy deactivation, and poor selectivity. The characterization results showed that Fe and Co were successfully supported on MCM41, and compared with other modified catalysts, Fe/Co-MCM41-85:15 (Fe/Co ratio is 1:1) possessed good thermal stability and microwave absorption properties. The pyrolysis oil yield and alkanes content were greatly improved after catalyzed, which reached the values of 71.91 wt% and 97.44%, respectively, while the oxygenates content was reduced to 0.88%. The Lewis and Brønsted acid sites of Fe/Co-MCM41-85:15 and the excellent pore structure stimulated catalytic activity, which could selectively convert waste engine oil into alkane-rich oil with a low oxygen content through hydrogen transfer, catalytic cracking, and deoxygenation. In-depth analysis of the microwave absorption-catalytic mechanism of the Fe/Co-MCM41-85:15catalys and the catalytic mechanism was investigated by density functional theory (DFT). The Fe/Co-MCM41-85:15 catalyst facilitated the conversion of long-chain paraffins in waste oil to saturated light alkanes. After the Fe/Co-MCM41-85:15 catalyst was used three times continuously, the pyrolysis oil yield was still above 65 wt%, showing good catalytic reuse and regeneration performance.

Catalytic microwave pyrolysis of mushroom spent compost (MSC) biomass for bio-oil production and its life cycle assessment (LCA)

Catalytic microwave pyrolysis of mushroom spent compost (MSC) biomass for bio-oil production and its life cycle assessment (LCA)

Phenolic-rich bio-oil production by microwave catalytic pyrolysis of switchgrass: Experimental study, life cycle assessment, and economic analysis

This study aims to determine the environmental impacts and feasibility of optimizing the production of phenolic-rich bio-oil, via switchgrass microwave catalytic pyrolysis. K3PO4 (Tripotassium phosphate) was used as the catalyst, at different temperatures, throughout this life cycle assessment (LCA) study. Results were compared with non-catalytic microwave pyrolysis (SiC-400) and conventional pyrolysis. K3PO4 (KP) was used as the microwave absorber and catalyst to enhance the low microwave absorption of switchgrass during microwave pyrolysis, and to improve the bio-oil quality and selectivity for phenolics production. Pyrolysis temperatures made a considerable difference to the LCA. There was an 86% reduction in the pyrolysis time when heating the sample to 300 °C (KP-300), as compared to 400 °C (KP-400), resulting in a significant reduction of the amount of energy required, and GHG's emitted. The total global warming potential (GWP) for microwave catalytic pyrolysis is observed within 159–223 kg CO2-eq/1000 kg of dried switchgrass (SG), with the baseline case (SiC-400) being the highest, and KP-300 being the lowest. Using the produced biochar, which is rich in nutrients for soil application, brings the net GWP to negative values through carbon sequestration. KP-300 also showed the highest selectivity for phenol and alkylphenols production, which increased by 252% and 420% respectively, compared to the baseline. The results clearly indicate that introducing K3PO4 showed great potential for accelerating microwave heating, and improving bio-oil selectivity towards alkylphenols, which can be used to replace petroleum-based phenol. This in turn can reduce GHG emissions, due to higher conversion efficiencies and lower energy consumption compared with non-catalytic microwave pyrolysis and conventional pyrolysis.

Bio-oil production from low-rank coal via novel catalytic microwave pyrolysis using activated carbon + Fe2(SO4)3 and HZSM-5 + Fe2(SO4)3

The need for clean-coal technology is still demanding to counter environmental issues. Global coal is dominated by low-rank coal (LRC). Microwave pyrolysis (MP) is an advanced technologies to convert LRC into clean energy such as bio-oil. However, the main pyrolysis challenges are low heating efficiency and the products dominated by heavy-tars. This study focused on MP to treat LRC using AC + Fe2(SO4)3 and HZSM-5 + Fe2(SO4)3 as catalysts and receptor. Effects on product distribution and process conditions (time, temperature, and power) were evaluated. Results showed that AC + Fe2(SO4)3 and HZSM-5 + Fe2(SO4)3 increased the rate of temperature rise and final temperature of MP, causing changes in product distribution. As compared to non-microwave or conventional catalytic pyrolysis (CP) at the same condition (620℃ and 60 min), bio-oil produced from MP + 1.0%AC + 24.6%Fe2(SO4)3 was 47.1%, 13.2% higher than the CP. Meanwhile, using MP + 1.0%HZSM-5 + 24.6%Fe2(SO4)3, 42.5% bio-oil was produced by an increase of 8.6%. Using 1.0%AC + 24.6%Fe2(SO4)3, the maximum bio-oil production was observed at 120 min, 620℃, and 450 W, generating 49.2% bio-oil. Meanwhile, using 1.0%HZSM-5 + 24.6%Fe2(SO4)3, the maximum bio-oil production was observed at 105 min, 620℃, and 525 W, generating 42.2% bio-oil. The outcomes of the studies could be a basis for future clean fuel production utilizing LRC that could reduce global carbon emission.

Enhancement of bio-oil quality over self-derived bio-char catalyst via microwave catalytic pyrolysis of peanut shell

Studies have indicated that a low-cost and high-efficiency treatment process is essential for converting agricultural waste into liquid fuels or chemicals. In the present work, the self-derived bio-char from peanut shell pyrolysis with the loading of selective transition metals (Fe, Co and Zn) were used as a catalyst for the production of more aromatic hydrocarbon contained bio-oil from the microwave pyrolysis of peanut shells. Py-GC/MS analysis results revealed that 10% loaded Fe/Bio-char increased the hydrocarbons in the bio-oil from 3.96% to 38.09%, and selectively, the aromatics hydrocarbon increased from 2.33% to 24.57%. The central combination design (CCD) optimized the microwave pyrolysis temperature and the catalyst to raw material ratio. The response surface area analysis showed that the temperature greatly influences aromatic hydrocarbon production more than the catalyst ratio to the substrate. At the pyrolysis temperature of 550 ℃ and the catalyst/peanut shell of 20%, the bio-oil yield was 24.3%, where the selectivity of hydrocarbon and aromatic hydrocarbon reached the maximum of 26.97% and 17.95%, respectively. The study of self-derived bio-char and the usage as a catalyst in pyrolysis of raw peanut materials under microwave conditions would be a high-value application for catalytic pyrolysis reactions to improve the utilization rate of biomass, reduce the reaction costs, and provide theoretical basis and technical support for the recycling and total utilization of agricultural waste.