Pyrolysis Of Corncob Research Articles

Microwave-assisted catalytic pyrolysis of corn cobs with Fe-modified Choerospondias axillaris seed-based biochar catalyst for phenol-rich bio-oil

In order to develop a more economical and easy-to-recover catalyst, this study prepared Fe-modified biochar catalyst by microwave pyrolysis carbonization and impregnation, and applied it to microwave catalysis pyrolysis of corn cobs to prepare phenol-rich bio-oil. The results showed that H3PO4 can greatly increase the specific surface area of the biochar catalyst. The Fe-modified biochar catalyst promoted the conversion of aldehydes and ketones in corn cobs bio-oil, thereby greatly increasing the content of phenolic compounds. Among them, Fe0.4@biochar had the best selectivity to phenol, approximately 16.45 area%. Fe0.2@biochar had the best selectivity to furfural, which was 10.68 area%. After repeated use for 5 times, the catalytic effect was still selective to phenolic compounds.

Studies on individual pyrolysis and co-pyrolysis of corn cob and polyethylene: Thermal degradation behavior, possible synergism, kinetics, and thermodynamic analysis

The knowledge on thermo-kinetics, synergistic effect, and reaction mechanism of pyrolysis/co-pyrolysis of biomass with plastics is crucial for designing efficient reactor system and subsequently the pyrolysis/co-pyrolysis process. The present work explores thermal response, kinetics, reaction mechanism and thermodynamic analysis of pyrolysis and co-pyrolysis of individual corn cob (CC) and polyethylene (PE), and their blend in the ratio of 3:1 (w/w). Thermogravimetric analysis (TGA) data was obtained under inert atmosphere at various heating rates of 10, 20, and 30 °C/min and synergistic effect in the co-pyrolysis of CC and PE is discussed. The obtained TGA data was processed using various model-free isoconversional methods like KAS, FWO, Friedman, Starink, and Vyazovkin for determination of kinetics of pyrolysis/co-pyrolysis process of CC and PE. Average activation energy for CC pyrolysis was estimated to be 240 ± 51.25 kJ/mol, 240 ± 51.51 kJ/mol, 237 ± 49.67 kJ/mol, and 245 ± 52.10 kJ/mol according to KAS, Starink, FWO, and Vyazovkin models, respectively. Statistical analysis showed that the variation in reported values of activation energy was not significantly different (p = 0.994). Similar statistically insignificant difference was also observed for pyrolysis of PE and co-pyrolysis of CC and PE. Results showed that co-pyrolysis (CC + PE) requires 10% less activation energy than pyrolysis of CC alone. For the co-pyrolysis process, the extent of synergistic effect was discussed by difference in mass loss (ΔW). Investigation also revealed that residue left for co-pyrolysis of CC and PE is 50% less than pyrolysis of CC alone showing synergistic effect during co-pyrolysis. Thermodynamic parameters were calculated to illustrate complex mechanism of the process. Third order reaction, 3D diffusion Jander, and Ginstling–Brounshtein (D4) models were found to be best fitted for CC pyrolysis, PE pyrolysis, and co-pyrolysis, respectively. Results obtained are expected to be useful in the design of corn cob and waste polyethylene co-pyrolysis systems.

Production of renewable phenols from corn cob using catalytic pyrolysis over self-derived activated carbons prepared with torrefaction pretreatment and chemical activation

The present work unveiled that the combination of chemical activation and torrefaction pretreatment was a promising approach for improving catalytic performance of activated carbon (AC) during conversion of corn cob into phenols. The characterization results demonstrated that P-containing functional groups (bands between 1000 and 1200 cm−1) were imbedded into AC samples successfully. The increase in acid concentration and carbonization temperature could improve the porosity of as-prepared ACs. GC/MS results revealed that the selectivity of phenols was boosted (from 19.0% to 79.3%) during pyrolysis of corn cob over torrefaction pretreated AC catalyst. The high carbonization temperature (from 369 °C to 581 °C) and H3PO4 concentration (from 26.7% to 83.3%) favored the selectivity of phenols attained. The optimal condition for phenols selectivity (79.3%) was achieved at a carbonization temperature of 550 °C with H3PO4 concentration of 75%. The current study may provide an efficient pathway of converting agriculture waste corn cob into AC catalyst and phenols-enriched bio-oil, simultaneously, which will advance the utilization of renewable agriculture biomass.

Ex-situ catalytic upgrading of corncob pyrolysis vapors into furans and phenols over Pt-Re/AC: Effect of Pt/Re ratio and process parameter

In order to improve the quality of bio-oils, catalytic fast pyrolysis of corncob over Pt/Re supported activated carbon (AC) catalysts was conducted to produce bio-furans and bio-phenols. The effect of Pt/Re ratio on the catalytic pyrolysis performance was evaluated. Pt and Re are uniformly dispersed on AC, but it results in the decrease of specific surface area. In addition, the amount of weak acidic sites increased and higher total weak acidity of Pt-Re/AC was contributed to the production of target products at low catalytic upgrading temperature. AC and Pt/AC inhibited the formation of phenols, and Re/AC and Pt-Re/AC promoted the formation of phenols. The relative peak area of furans over 1Pt-3Re/AC and Re/AC is 44.36 % and 41.98 %, respectively. Pt-Re/AC catalysts have a high selectivity for methylfurans (MFs) and phenol (P), remaining at 19 % ∼ 33 % and 17 % ∼ 21 %, respectively. Finally, 1Pt-3Re/AC showed good reuse performance.

Chemical analysis of corn cob-based biochar and its role as water decontaminants

Production of biochar is accomplished by pyrolysis of corncobs at 350 °C (BC-350) and 450 °C (BC-450) under oxygen-limited conditions. The chemical and physical properties were investigated via XRD, FTIR, BET, SEM and EDX analysis. Batch experiments were conducted for the adsorption of Pb2+ ions from aqueous solution onto biochar with regards to pH, contact time, biochar dose and initial Pb2+ concentration. The adsorption efficiency of Pb2+ was increased as increasing pH and biochar dose up to 1.5 g/L. Kinetic and isothermal studies demonstrated that the experimental data were fitted with the pseudo-second-order model, Langmuir and Freundlich isotherms. The study emphasized the preferable pyrolysis temperature which is 450 °C. According to the Dubinin-Kaganer-Radushkevich (DKR) model, the adsorption process of Pb2+ was a chemical and endothermic reaction. Results showed the applicability of corncob based biochar to be used as an efficient and low cost adsorbent for Pb2+ ions removal.

Pyrolysis of Corncobs to Produce Biobased Conductive Materials as Electrodes for Potential Application in Microbial Fuel Cells (MFCs)

Despite large varieties of commercially available electrodes, only few are suitable for electro-active bacterial colonization during biofilm formation in microbial fuel cells (MFCs), and most of these electrodes are cost prohibitive. Hence there is need to search for low-cost alternative electrodes for MFCs. Pyrochars were produced in this study by pyrolysis (600 °C and a continuous flow rate of 3 L/min of nitrogen gas for 30 min) and subsequently steam and potassium hydroxide (KOH) activation of the pyrochar at 600 °C were carried out accordingly. Physicochemical, structural, and electrochemical properties of the activated and non-activated pyrochars were determined according to standardized analytical methods. According to BET, 1626 m 2 g -1 surface area and 14.74 Å pore diameter were obtained from the KOH-activated pyrochar which was also the most conductive (0.26 S m -1 ). Chemical activation of pyrochar with KOH resulted in increased electrical conductivity (EC), pore diameter, and most importantly the material’s surface area according to the findings. In conclusion, KOH-activated corncob pyrochar holds potentials for producing electrode materials with desirable characteristics for successful application in MFC compared to the non-activated and steam-activated pyrochars of the same biomass.

Comparison of chemical reaction kinetic models for corn cob pyrolysis

This study used thermogravimetric analysis to investigate activation energy and pre-exponential factor of corn cob pyrolysis via various model-free methods. For applying kinetics of pyrolysis reaction in commercial simulation tools, a representative single reaction of overall pyrolysis reaction would be preferable in provided toolboxes. However, the kinetic parameters for this single reaction should be suitable to cover all the conversion range. Thus, the kinetic parameters were developed as polynomial regression models. The results showed that verification of using the quadratic regression models derived via Friedman method (Ea=−488.68X2+587.78X+64.104 and ln(A)=−106.58X2+116.71X+17.232) had very close agreement with the experiments in entire range of conversion. These regression models could be widely applied in slow pyrolysis and gasification. However, the constants derived via Ozawa–Flynn–Wall​ method (Ea=248.05 kJ mol−1 and A=3.05x1022 min−1) were simpler for use in some applications which had no effect of pyrolysis at temperature​ below 300 °C or conversion below 50%, like fluidized bed pyrolysis/gasification.

Pyrolysis of corn cob: physico-chemical characterization, thermal decomposition behavior and kinetic analysis

Abstract Bioenergy out of lignocellulosic biomass, especially from agricultural crop residues, is making massive inroads in our quest for sustainable environment. In the present study, detailed physico-chemical characterization, thermal degradation characteristics, and kinetics of pyrolysis of corn cob are reported. Thermogravimetric experiments were performed at different heating rates, such as, 10, 20, and 30 °C/min in an inert atmosphere. Thermogravimetric (TG) and derivative thermogravimetric (DTG) curves inferred the thermal behavior characteristics of corn cob. Significant content of cellulose and hemicellulose put together (76.23%) suggested tremendous potential of corn cob to give enhanced yield of bio-oil through pyrolysis. Maximum mass loss of 61.92% for corn cob was observed in the temperature range of 180–360 °C. The kinetic parameters for pyrolysis of corn cob were determined by employing model-free isoconversional methods like, Kissinger-Akahira-Sunose, Flynn-Wall-Ozawa, and Starink. Activation energy from FWO (62.44 kJ/mol) and Starink (61.74 kJ/mol) method for pyrolysis of corn cob was found to be in close proximity. The results revealed prospective bioenergy potential of corn cob as a feedstock for pyrolysis process.

The effect of torrefaction pre-treatment on the pyrolysis of corn cobs

Production of green fuels and chemicals from non-edible corn cob residues presents an excellent opportunity to produce sustainable low carbon energy vectors as an alternative to fossil fuels. The objective of this study was to optimize the fuel physical and chemical properties of torrefied corn cobs bio-oil by investigating the relationship between feedstock pre-treatment (torrefaction) temperatures (240, 260, 280 and 300 ​°C), and subsequent pyrolysis temperatures (400, 450, 500 and 550 ​°C). This experimental methodology aimed to improve both yields and properties of bio-oils from corn cobs. Torrefaction was first carried out as a pre-treatment step using a custom-built torrefaction reactor followed by pyrolysis using a continuous fluidized bed reactor. Torrefaction was found to be a promising pre-treatment step because it had the effect of reducing the water content and viscosity within the bio-oil. Corn cobs grinding energy requirements could be reduced by 69% when torrefaction was applied from 240 ​°C to 260 ​°C. A maximum bio-oil yield of 51.7% was achieved when the optimal temperatures (torrefaction 260 ​°C and pyrolysis 450 ​°C) was applied. Overall, using torrefaction as a pre-treatment step before pyrolysis was shown to be a promising approach for improving some physiochemical properties of bio-oil for its application as a fuel.

Production of renewable jet fuel and gasoline range hydrocarbons from catalytic pyrolysis of soapstock over corn cob-derived activated carbons

Selective production of jet fuel and gasoline range hydrocarbons from waste soapstock was achieved for the first time by catalytic pyrolysis over activated carbon catalyst that was prepared via pyrolysis of H3PO4-impregnated corn cob pyrolysis. Experimental results exhibited that the concentration of H3PO4 played an important role in acid groups and porous properties of prepared activated carbon catalyst. The obtained catalyst had a remarkable catalytic performance for C8–C16 aromatics formation with the highest selectivity of 89.97% in the bio-oil. In the meantime, the selectivities of jet fuel and gasoline range hydrocarbons could reach up to 98.78% and 91.03%, respectively. The bio-gas yield was improved with the increase in H3PO4 concentration, pyrolysis temperature and feedstock/activated carbon catalyst ratio, and the highest concentration of H2 (69.90 vol%) was achieved. The optimal reaction condition was at a pyrolysis temperature of 500 °C with a soapstock/ACC4 ratio of 1:1.5. In addition, a possible reaction mechanism was proposed for catalytic pyrolysis of soapstock over activated carbon catalyst. The current work might provide a novel, facile and efficient pathway to directly convert waste soapstock into valuable drop-in jet fuel and gasoline together with production of H2-rich syngas.

A study on the new type of radicals in corncob derived biochars

Biochars prepared from pyrolysis of biomass have been studied for a broad range of applications. It was reported that biochars contained radicals measurable by electron spin resonance (ESR) but the radicals have not been quantitatively related with the pyrolysis conditions nor with the chars’ structure. This work shows, through O2 adsorption or titration, that the chars derived from corncob pyrolysis in the temperature range of 300–750 °C contain 3 types of radicals, instead of the 2 types already reported in the literature, such as the one that reversibly adsorbs O2 and the one that does not adsorb O2. The newly found radicals in fresh corncob chars locate mainly at the methylene moieties linked to aromatic rings, and irreversibly disappear by exposure to O2, which leads to the formation of C–O and CO bonds. It is also found that the evolution of corncob char structure shows a two stage behavior, the first stage takes place in the pyrolysis temperatures of 300–600 °C while the second stage takes place in the pyrolysis temperatures of 600–750 °C. This two stage behavior can be characterized by the structural parameters determined commonly by 13C nuclear magnetic resonance, Raman spectroscopy, in-situ diffused reflectance Fourier Transform infrared spectroscopy, elemental composition, O2 adsorption, as well as ESR.

Thermal Degradation Conditions Effects on Selected Biomass Wastes and Characterization of Their Produced Biochar

Biochar has been proved to be effective in soil amelioration applications, carbon sequestration and also reduce GHG emissions which causes global warming. Biomass stands a greater chance of prevailing as a good source for the production of biochar, which in turn can be a solution for waste management. However, pyrolysis conditions for biochar production, together with feedstock characteristics largely control the physical and chemical properties of the yield biochar product. In this study, investigation on thermal degradation conditions effects on biochar production is carried out. Bio-char was produced using 35.3 litres fixed bed reactor from pyrolysis of Corn Cob (CC), Palm Kernel Shell (PKS) and Sugarcane Bagasse (SB) at temperatures ranging from 100°C to 500°C. The feedstock was also blended in ratio to each other and pyrolyzed to 250°C and 400°C. The analyzed results showed that higher pyrolysis temperatures resulted in lower bio-char mass recovery, higher ash contents, decreased fixed carbon and moisture content. Product characterization also showed that the produced biochar, independent of biomass waste type contained negligible amount of Sulphur (S) and Nitrogen which resulted in lower emission of SO2 and NO2 during the combustion process, this behaviour is observed to be more pronounced with the blended biochar samples investigated in this study as a result, the obtained bio-char product can be used directly for heating purposes. ANOVA test results for both volatile matter and Ash content of the produced biochar revealed that the P-value is greater than 0.01 independent of the biochar samples considered whereas for the fixed carbon of the same bio-char samples, P-value less than 0.01 is attained. These results show how control of biomass pyrolysis conditions can improve biochar chemical properties consequently biochar produced from biomass wastes could be a suitable candidate for alternative energy fuels in terms of quality and environment concern.

Hydrogen Production from Catalytic Microwave-Assisted Pyrolysis of Corncob Over Transition Metal (Fe, Co and Ni) Modified Palygorskite

Hydrogen Production from Catalytic Microwave-Assisted Pyrolysis of Corncob Over Transition Metal (Fe, Co and Ni) Modified Palygorskite

Continuous Saturated Steam Assisted Low‐temperature Pyrolysis of Corncobs and Selective Production of Furfural

AbstractA facile and selective furfural production technology was introduced by using corncobs as raw materials under saturated steam atmosphere in a fixed bed reactor. It was found that Al2(SO4)3 catalyst has showed a good selective performance with furfural selectivity 64.2% (15.8 wt%). The optimal conditions were pyrolysis temperature 230 °C, steam flow 10 g/min (160 °C) and catalyst loading 7.5 mmol. The reaction parameters such as pyrolysis temperature, catalyst loading and steam flow rate all displayed a positive effect on both corncob conversion and furfural selectivity.The higher steam flow displayed a positive effect on furfural dissolving and products desorption. Removal degree of hemicellulose on each catalytic condition analysis indicated that hemicellulose depolymerization was mainly promoted by lower temperature pyrolysis, and furfural selected production was mainly affected by catalytic effect. This technology provided a low‐cost and low‐temperature catalytic reaction to synthesize furfural, which shows a great potential in industrial production.

Upgrading of bio-oil via microwave-assisted pyrolysis of corncob over CaO and HZSM-5 mixed catalysts to promote the formation of aromatic hydrocarbons

Bio-oil upgrading via microwave-assisted pyrolysis of corncob over CaO and HZSM-5 mixed catalysts to promote the formation of aromatic hydrocarbon was investigated in this study. Results showed that with an increased ratio of HZSM-5 catalyst, the bio-oil yield was decreased; however, the proportion of aromatic hydrocarbons increased at first and then decreased. The maximum proportion of aromatic hydrocarbons was 35.8%, which was obtained with an optimal ratio of CaO to HZSM-5 of 1:2. This study showed the effects of CaO and HZSM-5 mixed catalysts under microwave-assisted pyrolysis in terms of improving the formation of aromatic hydrocarbons in bio-oil.

Selectively biorefining levoglucosan from NaOH pretreated corncobs via fast pyrolysis

Fast pyrolysis is a comparable technology with enzyme or acid hydrolysis for saccharification of biomass. The low yield of levoglucosan and the formation of inhibitors to biocatalysts from lignocellulose hamper the fermentable utilization of pyrolysate. In this study, aiming to enhance the production of levoglucosan, dilute alkali pretreatment was performed prior to fast pyrolysis of corncobs. The yield of levoglucsoan from pretreated corncobs was significantly improved (34.8%) as compared to that from un-treated corncobs (3.0%), which was mainly attributed to the removal of alkaline and alkaline earth metals as well as lignin fraction by NaOH pretreatment. Conversely, NaOH pretreatment suppressed the formation of acids (from 11.1 to 2.2%), furans (from 2.5 to 2.0%), ketones (from 15.7 to 9.8%) and phenols (from 4.8 to 1.3%), which were common inhibitors to the biocatalysts. Accordingly, NaOH pretreatment facilitated further selective conversion of biomass in fast pyrolysis and made the pyrolysate more fermentable.

Catalytic fast pyrolysis of corn cob in ammonia with Ga/HZSM-5 catalyst for selective production of acetonitrile

In this work, corn cob was used as raw material to selectively produce acetonitrile via catalytic fast pyrolysis (CFP) in ammonia over Ga/HZSM-5 catalyst. A series of catalysts with different catalyst carriers (including HZSM-5, USY, MCM-41, HY, and γ-Al2O3) and active metals (including Fe, Co, Ni, Cu, Zn, Cr, Ca, Mg and Ga) were prepared and screened. The reaction conditions, such as temperature, ammonia flow rate and residence time were changed to investigate the effect on the product distribution and acetonitrile production. The results indicated that with the desired catalyst (2% Ga/HZSM-5) and optimal reaction conditions (Temperature 700 °C; ammonia flow rate 80 ml/min; residence time 2.4 s), the highest carbon yield of acetonitrile from corn cob with a value of 18.4% could be obtained, and the carbon selectivity in bio-oil was 83.5%. This study provides an economical and environmental-friendly method for the direct production of acetonitrile from abundant biomass.

Acid washed lignite char supported bimetallic Ni-Co catalyst for low temperature catalytic reforming of corncob derived volatiles

Acid washed Shengli lignite (AWSL) supported Ni, Co and Ni-Co catalysts were prepared, characterized and evaluated in catalytic reforming (CR) of corncob pyrolysis volatiles at a relatively low catalytic temperature of 450 °C. Moreover, the production and selectivity of H2 were also investigated. Amongst the catalysts studied, bimetallic Ni-10%Co/AWSL exhibited the most remarkable activity, yielding 36.3 mmol H2/g corncob and 710 μmol min−1 g−1 formation rate of syngas (H2 + CO + 4CH4) with trace of tar. It also tuned the gas composition and showed the greatest selectivity of H2 due to the promotion of the water gas shift reaction (with H2 accounting for the maximum 50.3% and 63% under Ar and steam atmosphere, respectively). Regardless of the loss of specific surface area, the superior performance of Ni-Co based catalysts under mild circumstance was attributed to the better reducibility and electronic properties along with a high dispersion of active metal. Additionally, the synergy of Ni and Co contributed to the combined and enlarged activity for CR of corncob volatiles and great selectivity for H2-rich syngas under moderate condition.

Two-step pyrolysis of corncob for value-added chemicals and high-quality bio-oil: Effects of alkali and alkaline earth metals

Two-step pyrolysis (TSP) of corncob(CC) coupled with water and acid washing pretreatment was conducted to investigate the effects of alkali and alkaline earth metals (AAEMs) on TSP by Py-GC/MS. TG-FTIR was used to analyze the pyrolysis characteristics of the samples. The results showed that the removal of AAEMs postponed the pyrolysis process and significantly influenced the distribution of the pyrolysis products. As the content of AAEMs decreased, the bio-oil yield increased and the biochar yield decreased. TSP of CC achieved high selectivities for phenols and ketones in the first step and for hydrocarbons in the second step. TSP of acid-washed corncob (ACC) achieved high selectivities for furans in the first step and for sugars in the second step. Additionally, some value-added chemicals such as furfural (11.54%, ACC), 4-vinylphenol (23.57%, CC) and levoglucosan (43.05%, ACC) were also enriched in TSP. Therefore, a promising polygeneration scheme of TSP for the efficient utilization of biomass was proposed.

Selective production of anhydrosugars and furfural from fast pyrolysis of corncobs using sulfuric acid as an inhibitor and catalyst

The objective of this study was to selectively coproduce anhydrosugars and furfural from the fast pyrolysis of biomass by H2SO4 impregnation. The pyrolysis behaviors of raw and H2SO4-impregnated corncobs, cellulose and xylan were systematically studied by a thermogravimetric analyzer (TGA) and commercial pyroprobe reactor. The results demonstrate that H2SO4 impregnation can reduce the formation of char and drastically improve the yield of anhydrosugars and furfural. The maximum yields of levoglucosan (38.45 wt% based on cellulose), furfural (19.18 wt% based on hemicellulose) and xylosan (9.49 wt% based on hemicellulose) were obtained by fast pyrolysis of corncobs impregnated with 2.75 wt% H2SO4. By comparing the product distributions from fast pyrolysis of H2SO4-impregnated cellulose, xylan, and raw and demineralized corncobs, it is concluded that H2SO4 can act as an inhibitor to suppress the catalytic functions of structural alkali and alkaline earth metals (AAEM) to improve the yield of anhydrosugars, and H2SO4 can also act as a catalyst to accelerate the dehydration of hemicellulose to form more furfural. It is speculated that H2SO4 could first react with structural AAEM in lignin to form lignosulfonates (e.g., potassium lignosulfonate), thus reducing the catalytic functions of structural AAEM during fast pyrolysis of corncobs. These findings provide a simple and efficient method for the selective coproduction of anhydrosugars and furfural from waste biomass.