Pyrolysis Of Corncob Research Articles

Quantitative and kinetic TG-FTIR investigation on three kinds of biomass pyrolysis

Biomass is applied in power generation or heat production as renewable energy resources. This paper focused on the pyrolysis in thermogravimetric (TG) analyzer of three biomasses, corn cob, tree root and bagasse, which showed different characteristics on their differential thermogravimetric (DTG) curves. In pyrolysis of corn cob, tree root and bagasse, there were three, one and two obvious peaks of DTG curves, respectively. Thermogravimetric Fourier Transform Infrared (TG-FTIR) analysis showed that the maximum mass loss rate at DTG curves was mainly due to cellulose and lignin pyrolysis, and the second mass loss rate peak of corn cob and the first one of bagasse were mainly due to pyrolysis of hemicellulose; while the first mass loss rate peak of corn cob was most likely due to breaking off of OH stretching function groups and H2O generation of sucrose pyrolysis. The main typical gaseous products were CO2, CO, H2O, CH4, NH3 and acid & aldehydes (CH3COOH or furadelhyde). Quantitative FTIR analysis showed that CO produced variation and CO2 produced before 400°C fitted with DTG curves well. IR results also indicated that hemicellulose pyrolysis had higher CH3COOH generation. Distributed activated energy model (DAEM) was applied to analyze kinetics of biomass pyrolysis. Similar to their DTG curves, the activation energy (AE) of corn cob showed four high distributions, in which the distributions of about 174.7kJ/mol and 181.6kJ/mol were highest (more than 20%), followed by that of 161.1kJ/mol (18.91%) and 140.5kJ/mol (9.08%); the AE of tree root had a distinctive distribution, which was as high as 33.9% at 181.6kJ/mol; while that of bagasse had only two distributions more than 6.8%, one is 50.69% at 181.6kJ/mol, and the other is 25.43% at 167.9kJ/mol. The pseudo-reactions fitting curves showed that the pyrolysis of corn cob was more complicated than the other two, because of more obvious pseudo-reactions contributed to the DTG curve and there were more than three main components in corn cob. It indicated that pseudo-reaction at 181.6kJ/mol was mainly contributed to cellulose pyrolysis in DTG curves, and those at 161.1kJ/mol and 167.9kJ/mol were mainly contributed to hemicellulose pyrolysis, while pseudo-reaction at 174.7kJ/mol might relate to the pyrolysis of sucrose.

Co-production of furfural and acetic acid from corncob using ZnCl2 through fast pyrolysis in a fluidized bed reactor

Corncob was pyrolyzed using ZnCl2 in a pyrolysis plant equipped with a fluidized bed reactor to co-produce furfural and acetic acid. The effects of reaction conditions, the ZnCl2 content and contacting method of ZnCl2 with corncob on the yields of furfural and acetic acid were investigated. The pyrolysis was performed within the temperature range between 310 and 410°C, and the bio-oil yield were 30-60 wt% of the product. The furfural yield increased up to 8.2 wt%. The acetic acid yield was maximized with a value of 13.1 wt%. A lower feed rate in the presence of ZnCl2 was advantageous for the production of acetic acid. The fast pyrolysis of a smaller corncob sample mechanically mixed with 20 wt% of ZnCl2 gave rise to a distinct increase in furfural. A high selectivity for furfural and acetic acid in bio-oil would make the pyrolysis of corncob with ZnCl2 very economically attractive.

Kinetics of Corncob Pyrolysis

Two different corncob samples from different continents and climates were studied by thermogravimetry at linear and nonlinear heating programs in inert gas flow. A distributed activation energy model (DAEM) with three and four pools of reactants (pseudocomponents) was used due to the complexity of the biomass samples of agricultural origin. The resulting models described well the experimental data. When the evaluation was based on a smaller number of experiments, similar model parameters were obtained which were suitable for predicting experiments at higher heating rates. This test indicates that the available experimental information was sufficient for the determination of the model parameters. The checks on the prediction capabilities were considered to be an essential part of the model verification. In another test, the experiments of the two samples were evaluated together, assuming more or less common kinetic parameters for both cobs. This test revealed that the reactivity differences between the two...

Catalyst Screening for the Production of Furfural from Corncob Pyrolysis

Acidic pyrolysis of corncobs is carried out at 800 K in a packed-bed reactor using several catalysts (H2SO4, H3PO4, H3BO3, (NH4)2SO4, ZnCl2, NiCl2, MgCl2, and Fe2(SO4)3). In all cases, the yields of char, water, and some condensable organic compounds (acetic acid, levoglucosenone, 1,4:3,6-dyanhydro-α-d-glucopyranose, and furfural) are significantly increased at the expense of the phenolic and carbohydrate products typical of uncatalyzed pyrolysis. The maximum yields of furfural (FF) are around 5–6% for the H2SO4, Fe2(SO4)3 ,and ZnCl2 treatments, with potential further increase, following secondary degradation of the main anhydrosugars, up to 8.5% (H2SO4, Fe2(SO4)3) or 6.5% (ZnCl2). Additional experiments made with a wide range of Fe2(SO4)3 concentrations, and a comparison with previous results obtained for H2SO4 and ZnCl2 treatments indicate that the best performances are shown by the first catalyst with potential FF yields up to 10%. Moreover, at low concentrations, it also highly promotes the formation ...

Bio-oil production from pyrolysis of corncob (Zea mays L.)

Pyrolysis experiments have been conducted on a sample of corncob to determine the effects of pyrolysis temperature, heating rate and sweep gas flow rate on the pyrolysis product yields and their chemical compositions. The temperature of pyrolysis, heating rate and sweep gas flow rate were varied in the ranges of 400–550 °C, 7–40 °C min−1 and 50–200 cm3 min−1, respectively. The maximum oil yield of 26.44 wt.% was obtained at a pyrolysis temperature of 500 °C, heating rate of 40 °C min−1 and sweeping gas flow rate of 100 cm3 min−1. The elemental analysis and calorific value of the oil were determined, and the chemical composition of the oil was investigated using chromatographic and spectroscopic techniques (column chromatography, FTIR, 1H-NMR). Chromatographic and spectroscopic studies on the bio-oil showed that the bio-oil obtained from corncob could be used as a renewable fuel and chemical feedstock with a calorific value of 26.22 MJ kg−1 and empirical formula of CH1.34O0.28N0.01.

Nitrogen and Phosphorus Availability in Biochar-Amended Soils

Biochar, a solid coproduct from the thermochemical production of bioenergy, has been reported to increase nutrient availability in soils through increased cation retention and decreased phosphate adsorption. The objectives of this study were to determine biochar effects on N and P availability in the presence and absence of external nutrient inputs. Biochar was obtained from hydrothermal pyrolysis of corn cobs at 305°C with 20 min of retention time. Biochar was added to two soils at three biochar rates (0, 2, and 20 g/kg) in combination with either two N rates (0 and 100 mg/kg) or two P rates (0 and 20 mg/kg) and incubated for 56 days. Soils were extracted for Mehlich-3 P and KCl-extractable NO3-N and NH4-N at 0, 3, 10, 17, 28, and 56 days after soil amendment. Biochar application at 20 g/kg increased NH4-N concentrations by 1.1 to 4.8 mg kg−1 during the first 10 days and consistently decreased NO3-N recovery by 5 to 10 mg kg−1 for the duration of the study. Biochar decreased Mehlich-3 P concentrations in soil by 0.9 mg kg−1 in the absence of P additions and increased Mehlich-3 P concentrations by 3.3 mg kg−1 when added with a P source. Furthermore, biochar increased Mehlich-3-extractable P by 5.4 mg kg−1 in the soil when applied with N fertilizer. Results indicate that biochar-amended soils may need additional N after biochar addition to maximize crop production.

Valorisation of corncob residues to functionalised porous carbonaceous materials for the simultaneous esterification/transesterification of waste oils

Functionalised porous carbonaceous materials prepared from the controlled pyrolysis of corncobs were found to provide excellent activities in the simultaneous esterification/transesterification of highly acidic waste oils to biodiesel-like mixtures. Materials carbonised at 600 °C (mostly microporous) containing –SO3H groups (ca. 1 wt% S, 0.16 mmol g−1 –SO3H) exhibited the optimum yields (>95%) to fatty acid methyl esters after 6 h of reaction.

H2SO4-Catalyzed Pyrolysis of Corncobs

The acid-catalyzed pyrolysis of corncobs is investigated for the production of chemicals (in particular furfural) and bioproducts. Particles, preimpregnated with H2SO4 concentrations up to about 4%...

Pyrolysis of Corncobs Catalyzed by Zinc Chloride for Furfural Production

The pyrolysis of corncobs impregnated with variable amounts of zinc chloride (ZnCl2) (up to 11%, on a dry sample mass basis) is investigated and compared with fir wood results. As expected, a continuous increase with the amount of impregnated catalyst in corncobs is observed of the formation rates of char and water (total yields from 46% up to 64%) associated with a decline in the yields of organic condensable products (from 38% to 18%) and gas (from 13% to 9%). Moderate ZnCl2 concentrations (2%−5%) favor the production of levoglucosenone (from trace amounts to 1%), acetic acid (from 4% to 6%), and furfural (from 0.65% to 6%). Moreover, low values, although causing the prompt decay in the yields of hydroxyacetaldehyde, hydroxypropanone, levoglucosan, minor carbohydrates, phenols, and guaiacols, enhance the formation rate of 5-hydroxy-methylfurfural, 4-hydroxy-5,6-dihydro-(2H)-pyran-2-one, 1-hydroxy-3,6-dioxabicyclo[3.2.1]octan-2-one, and 1,4:3,6-dianhydro-α-d-glucopyranose. Results support the speculation that dehydrated cellulose and galactoglucomannan hemicellulose produce levoglucosenone and 1,4:3,6-dianhydro-α-d-glucopyranose, instead of levoglucosan, which are then catalytically decomposed to other products, including furfural. ZnCl2 also catalyzes the primary paths of furfural formation via dehydration of pentosyl and glucosyl residues, with a stronger action on the former.

Comparison of catalytic pyrolysis of biomass with MCM-41 and CaO catalysts by using TGA–FTIR analysis

Pyrolysis of corncob with and without catalyst was investigated using thermogravimetry analyzer coupled with Fourier transform infrared spectroscopy (TGA–FTIR). The effects of two completely different catalysts, acid catalyst (MCM-41) and base catalyst (CaO), on the formation characteristics and composition of pyrolysis vapor were studied. The results show that these two catalysts give different product distributions. For catalytic run with MCM-41, the molality of carbonyl compounds decreases 10.2%, while that of phenols, hydrocarbons and CH 4 increases 15.32%, 4.29% and 10.16% compared with non-catalytic run, respectively. The increase of phenols exhibits in a wide temperature range from about 295 °C to 790 °C in the catalytic run with MCM-41 catalyst. However, the use of CaO in pyrolysis of corncob leads to a huge change of product distribution. The molality of acids decreases 75.88%, while the molality of hydrocarbons and CH 4 increases 19.83% and 51.05% compared with non-catalytic run, respectively. CaO is very effective in deacidification and the conversion of acids promotes the formation of hydrocarbons and CH 4. Catalytic pyrolysis of corncob with CaO shows two main weight-loss stages. The first stage is from 235 °C to 310 °C with a weight loss of 31%. The second stage is from 650 °C to 800 °C with a weight loss of 21%.

Microwave Pyrolysis of Corn Cob and Characteristics of the Pyrolytic Chars

Microwave pyrolysis is a new process for converting biomass to bio-oil, syngas, and solid char. In this study, pyrolysis of corn cob was performed in an inert environment at atmospheric pressure and temperatures ranging from 300 to 600°C. The aim of this work was to study the effect of pyrolysis conditions on the characteristics of the solid char residue. The char was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, elemental analyzer, BET surface area analysis, and inductive coupled plasma. The char yield from pyrolysis decreased significantly to 23% with an increase in temperature to 600°C. SEM analysis indicated that pyrolysis of corn cob led to a stepwise accumulation of inorganic matter onto the exposed surface, and some organic matter melted, resulting in the formation of hollow cavities by the evolving volatiles. Fourier transform infrared spectroscopy results showed a continuous decrease in the intensity of the hydroxyl group stretch with temperature and the aromatic group to be at maximum at 600°C. Elemental analysis indicated both H/C and O/C ratio decreased continuously with increasing temperature to 450°C then became constant at higher temperatures.

Catalytic Fast Pyrolysis of Biomass in a Fluidized Bed with Fresh and Spent Fluidized Catalytic Cracking (FCC) Catalysts

The conversion of biomass into bio-oil using fast pyrolysis technology is one of the most promising alternatives to convert biomass into liquid products. However, substituting bio-oil for conventional petroleum fuels directly may be problematic because of the high viscosity, high oxygen content, and strong thermal instability of bio-oil. The focus of the current research is decreasing the oxygen and polymerization precursor content of the obtained bio-oil to improve its thermal stability and heating value. Catalytic fast pyrolysis of corncob with different percentages (5, 10, 20, and 30% by volume) of fresh fluidized catalytic cracking (FCC) catalyst (FC) and spent FCC catalyst (SC) in bed materials was conducted in a fluidized bed. The effects of the catalysts on the pyrolysis product yields and chemical composition of the bio-oil were investigated. A greater catalyst percentage lead to a lower bio-oil yield, while a lower catalyst percentage lead to little change of the composition of the bio-oil. The best percentages of FC and SC were 10 and 20%, respectively. FC showed more catalytic activation in converting oxygen into CO, CO2, and H2O than SC, but the oil fraction yield with FC was remarkably lower than that with SC because of more coke formation. The gas chromatography/mass spectrometry (GC/MS) analysis of the collected liquid in the second condenser showed that the most likely polymerization precursors, such as 2-methoxy-phenol, 2-methoxy-4-methyl-phenol, 4-ethyl-2-methoxy-phenol, 2-methoxy-4-vinylphenol, and 2,6-dimethoxy-phenol decreased, while monofunctional phenols, ketones, and furans increased compared to that in the noncatalytic experiment. The hydrocarbons increased with the increase of the catalyst percentages, and this contributed to the decrease of the oxygen content of the bio-oil. Multi-stage condensation achieved a good separation of the oil fraction and water.

Influence of temperature and alumina catalyst on pyrolysis of corncob

Corncob has been investigated as an alternative feedstock to obtain fuels and chemicals via pyrolysis in fixed-bed reactor. The influence of pyrolysis temperature in the range 300–800 °C as well as the catalyst effects on the products was investigated in detail and the obtained results were compared. The results indicated that a maximum oil yield of 22.2% was obtained at a moderate temperature of 600 °C. The oil yield was reduced when the temperature was increased from 600 to 800 °C, whereas the gas yield increased. Pyrolysis oils were examined by using instrumental analysis, 1H NMR spectroscopy and GC/MS. This analysis revealed that the pyrolysis oils were chemically very heterogeneous at all temperatures. It was determined that the most abundant compounds composing the bio-oil were phenolics. It was observed that the catalyst decreased the reaction temperature. Most of the components obtained using a catalyst at moderate temperatures was close to those obtained at high temperatures without using a catalyst. Moreover, the use of a catalyst and the high temperatures of the reactions also decreased the amount of oxygenated compounds produced. According to these results, corncob bio-oils can be used as fuel and constitute a valuable source of chemical raw materials.

Comparison of non-catalytic and catalytic fast pyrolysis of corncob in a fluidized bed reactor

Fast pyrolysis of corncob with and without catalyst was investigated in a fluidized bed to determine the effects of pyrolysis parameters (temperature, gas flow rate, static bed height and particle size) and a HZSM-5 zeolite catalyst on the product yields and the qualities of the liquid products. The result showed that the optimal conditions for liquid yield (56.8%) were a pyrolysis temperature of 550 °C, gas flow rate of 3.4 L/min, static bed height of 10 cm and particle size of 1.0–2.0 mm. The presence of the catalyst increased the yields of non-condensable gas, water and coke, while decreased the liquid and char yields. The elemental analysis showed that more than 25% decrease in oxygen content of the collected liquid in the second condenser with HZSM-5 was observed compared with that without catalyst. The H/C, O/C molar ratios and the higher heating value of the oil fraction in the collected liquid with the catalyst were 1.511, 0.149 and 34.6 MJ/kg, respectively. It was indicated that the collected liquid in the second condenser had high qualities and might be used as transport oil.

Synergies in co-pyrolysis of Thai lignite and corncob

The results from TGA experiments at the temperature range of 300–600 °C evidently distinguished the different pyrolysis behaviours of lignite and corncob; however, no clear synergistic effects could be observed for the mixture. The investigation of co-pyrolysis in a fixed-bed reactor, however, found significant synergies in both pyrolysis product yields and gas product compositions. The solid yield of the 50:50 lignite/corncob blend was much lower (i.e. 9%) than expected from the calculated value based on individual materials under the range of temperatures studied, and coincided with the higher liquid and gas yield. The synergistic effect in product gas composition was highly pronouncing for CH 4 formation, i.e. three times higher than the calculated value at 400 °C. Possible mechanisms were described including the interaction between corncob volatiles and lignite particles, and the effect of the heat profiles of lignite and corncob pyrolysis on the temperature dependent reactions. The enhanced devolatilisation of the blend was explained by the transfer of hydrogen from biomass to coal as well as the promotion of low-temperature thermal decomposition of lignite by exothermic heat released from corncob pyrolysis. Moreover, water, which was one of the major components in corncob volatiles produced mainly at around 200–375 °C, can also be expected to act as a reactive agent to promote the secondary tar cracking producing more CH 4.

Consecutive Reaction Model for the Pyrolysis of Corn Cob

Detailed information on the pyrolysis characteristics of corn cob was obtained. A thermogravimetric analysis including determination of kinetic parameters was performed over the temperature range of 373 to 1073 K at controlled heating rates of 10 to 30 K min-1 and with various particle sizes. Under the conditions studied, the heating rate has a significant effect on the pyrolysis process, while the particle size has little effect. A one-step global model and a two-step consecutive-reaction model were developed to simulate this pyrolysis of corn cob and to determine the kinetic parameters. Although various chemicals are released during pyrolysis, global kinetics are looked to as offering a clue to the key mechanistic steps in the overall degradation process. The model predictions are in agreement with the thermal degradation over a wide range of chosen temperatures and particle sizes.

Pyrolysis of corncobs at fluidization*

Pyrolysis of corncob particles was conducted in nitrogen in an externally heated benchscale fluidized bed reactor. Test results are presented with a demonstration of their application in gasification modeling.