Physicochemical and thermal characterization of nonedible oilseed residual waste as sustainable solid biofuel

Pyrolytic biochar from plastic film waste addition on farmland for maize growth improvement: Process and effect study

Pyrolyzing and returning to farmland is one of the potential methods for farmland plastic film waste. This study explored both pyrolyzation and activation optimum conditions of a mixture of plastic film (polyethylene) and maize straw (MPS) in a 1:5 ratio to produce MPS-char, investigated the action of the char on the maize seedling stage (for 30 days). The results showed that the char promoted the root to be more advanced than aboveground part, therefore, this study experimentally clarified the role MPS-char played when added to the soil. The functional groups of the char were varied by the participation of polyethylene. Carbon-based groups were observed, such as carbonyl or carboxyl groups, which could constitute an NH₄⁺ absorption release system to increase the existence of urea in soil, therefore the average nitrogen concentration was improved by 16.18 %. However, the shallow soil temperature increased by 2.03 °C, and the deep soil temperature slightly decreased with the effect of MPS-char. While, the soil moisture content was slightly reduced in the second half of the experiment, and the soil oxygen content increased by 7.64 % throughout the whole experiment. Overall, returning MPS-char to farmland showed a positive effect on maize growth, which was caused by the variation of both chemical and physical properties. This variation provides opportunities for further promotion of rhizosphere development.

Assessment of the Catalytic Performances of Nanocomposites Materials Based on 13X Zeolite, Calcium Oxide and Metal Zinc Particles in the Residual Biomass Pyrolysis Process

Nanocomposites based on 13X zeolite (13XZ), calcium oxide (CaO) and metal zinc particles (Zn) were prepared. The resulting nanocomposites were characterized by different techniques. Then, a comparative study on catalytic and noncatalytic pyrolysis of biomass waste was performed to establish the influence of nanocomposites used as catalysts on the yields and characteristics of liquid and solid products. Residual rapeseed biomass (RRB) was employed for pyrolysis experiments and a fixed bed reactor was used. By introducing CaO and metal zinc particles into 13X zeolite mass, the surface area (S_BET) of nanocomposites was reduced, and this decrease is due to the introduction of nano-calcium carbonate and nano-zinc particles, which occupied an important space into zeolite structure. By adding CaO to 13XZ, the pore structure was changed and there was a decrease in the micropores volume. The analysis of the pore area distribution showed a hierarchical pore structure for nanocomposites. The elements composition showed that the main elements contained in nanocomposites are Si, Al, Ca and Zn, confirming the preservation of the zeolite structure. Using these nanocomposites as catalysts in pyrolysis process, the residual biomass could be valorized, producing bio-oil and biochar for the management and sustainability of this low-value waste.

Physicochemical, structural analysis of coal discards (and sewage sludge) (co)-HTC derived biochar for a sustainable carbon economy and evaluation of the liquid by-product

This study focused on the hydrothermal treatment (HTC) of coal tailings (CT) and coal slurry (CS) and the co-hydrothermal treatment (Co-HTC) of CT, CS and sewage sludge to assess the potential for increasing the carbon content of the hydrochar produced as an enabler for a sustainable carbon economy. The optimal combination methodology and response surface methodology were used to study the relationship between the important process parameters, namely temperature, pressure, residence time, the coal-to-sewage-sludge ratio, and the carbon yield of the produced hydrochar. The optimized conditions for hydrochar from coal tailing (HCT) and hydrochar from coal slurry (HCS) (150 °C, 27 bar, 95 min) increased fixed carbon from 37.31% and 53.02% to 40.31% and 57.69%, respectively, the total carbon content improved from 42.82 to 49.80% and from 61.85 to 66.90% respectively whereas the ash content of coal discards decreased from 40.32% and 24.17% to 38.3% and 20.0% when compared CT and CS respectively. Optimized Co-HTC conditions (208 °C, 22.5bars, and 360 min) for Hydrochar from the blend of coal discards and sewage sludge (HCB) increased the fixed carbon on a dry basis and the total carbon content from 38.67% and 45.64% to 58.82% and 67.0%, when compared CT and CS respectively. Carbonization yields for HCT, HCS, and HCB were, respectively, 113.58%, 102.42%, and 129.88%. HTC and Co-HTC increase the calorific value of CT and CS, to 19.33 MJ/kg, 25.79 MJ/kg, respectively. The results further show that under Co-HTC conditions, the raw biomass undergoes dehydration and decarboxylation, resulting in a decrease in hydrogen from 3.01%, 3.56%, and 3.05% to 2.87%, 2.98%, and 2.75%, and oxygen from 8.79%, 4.78, and 8.2% to 5.83%, 2.75%, and 6.00% in the resulting HCT, HCS, and HCB, respectively. HTC and Co-HTC optimal conditions increased the specific surface area of the feedstock from 6.066 m²/g and 6.37 m²/g to 11.88 m²/g and 14.35 m²/g, for CT and CS, respectively. Total pore volume rose to 0.071 cm³/g from 0.034 cm³/g, 0.048 cm³/g, and 0.09 cm³/g proving the ability of HTC to produce high-quality hydrochar from coal discards alone or in conjunction with sewage sludge as precursors for decontamination of polluted waters, soil decontamination applications, solid combustibles, energy storage, and environmental protection.

Pyrolysis of low-value waste switchgrass: Physicochemical characterization, kinetic investigation, and online characterization of hot pyrolysis vapours

The present study is dedicated to physicochemical characterization, kinetic, thermal degradation behaviors, and online characterization of vapour products through Py-GC-MS and TGA-FTIR. The feasibility study was attained via proximate, ultimate, fibre analysis, and extractive analysis, whereas Vyazovkin (VM), Ozawa-Flynn-Wall (OFW), Kissinger-Akahira-Sunose (KAS), Coats-Redfern (CR), and Distributed Activation Energy Model (DAEM) were employed for kinetics exploration. The feasibility study showed its tremendous ability to be used as pyrolysis feedstock. TGA-FTIR documented the maximum release of CO₂ (26.22%), carbonyls (25.04%), and hydrocarbons (15.93%). Further, kinetic investigation of SWG documented an increased trend of activation energy against progressive conversion. The apparent average activation energy from KAS, OFW, DAEM, and VM was found to be 126.03, 137.54, 130.33, 134.26 kJ mol^-1, respectively. Also, kinetics reaction mechanisms are exposed to the multi-nature of decomposition of biomass. Furthermore, the Py-GC-MS investigation established increased hydrocarbons (6.49-11.54%) and reduced oxygen-containing products (24.17-17.27%) with an increased temperature.

Pyrolysis of mustard straw: Evaluation of optimum process parameters, kinetic and thermodynamic study

The aim of this work was to evaluate the pyrolysis of mustard straw (MS) in a thermogravimetric analyser and in a tubular reactor to recognize its bioenergy capability. The model free methods of Ozawa-Flynn-Wall (OFW), Kissinger-Akahira-Sunose (KAS) and Vyazovkin were employed for kinetic analysis and Coats-Redfern (CR) method for elucidating the reaction mechanism. Response surface methodology (RSM) with central composite design technique was employed to optimize the pyrolysis process parameters to gain maximum amount of bio-oil. The highest bio-oil yield (44.69%) was obtained at the heating rate of 25 °C/min and at 500 °C under inert condition (N₂ gas flow rate = 100 ml/min). Further, FTIR and GCMS analysis of bio-oil revealed the presence of different functional groups and valuable chemicals, whereas physicochemical characterization revealed its fuel characteristic. The results confirmed the suitability of mustard straw as a feed-stock for obtaining a cleaner fuel and value added products.

NaOH-Catalyzed Methanolysis Optimization of Biodiesel Synthesis from Desert Date Seed Kernel Oil

Biodiesel synthesis from non-edible vegetable oil via catalytic transesterification is one of the effective ways to replace petroleum-based fuels in the area of renewable energy development and is beneficial to environmental security. Therefore, this research investigates the optimization of process parameters (temperature, methanol to oil ratio, and NaOH catalyst dose) for the conversion of biodiesel from non-edible desert date (Balanites Aegyptiaca) seed kernel oil using the Box-Behnken experimental design of response surface methodology statistical analysis. Accordingly, the optimum values of reaction conditions, namely, a temperature of 60.5 °C, methanol to oil ratio of 6.7:1, and catalyst dose of 0.79 %wt, yielded 93.16% biodiesel. Fourier transform infrared spectroscopy analysis confirmed the cracking of a single glycerol backbone from the triglycerides and the substitution by methoxyl in the presence of a NaOH catalyst. The physicochemical properties of the biodiesel were investigated and compared with standards in terms of its density, viscosity, higher heating value, acid value, saponification value, cetane number, cloud point, pour point, and flash point, and the values are within the recommended standard limits of American Standard for Testing Material (ASTM D6751) and European Committee for Standardization (EN14214). Thus, the results revealed that homogeneous base catalysis of non-edible oil under optimum reaction conditions provides high yield of biodiesel.

Municipal Solid Waste Thermal Analysis—Pyrolysis Kinetics and Decomposition Reactions

In this study, 12 organic waste materials were subjected to TG/DTG thermogravimetric analysis and DSC calorimetric analysis. These analyses provided basic information about thermochemical transformations and degradation rates during organic waste pyrolysis. Organic waste materials were divided into six basic groups as follows: paper, cardboard, textiles, plastics, hygiene waste, and biodegradable waste. For each group, two waste materials were selected to be studied. Research materials were (i) paper (receipts, cotton wool); (ii) cardboard (cardboard, egg carton); (iii) textiles (cotton, leather); (iv) plastics (polyethylene (PET), polyurethane (PU)); (v) hygiene waste (diapers, leno); and (vi) biodegradable waste (chicken meat, potato peel). Waste materials were chosen to represent the most abundant waste that can be found in the municipal solid waste stream. Based on TG results, kinetic parameters according to the Coats–Redfern method were determined. The pyrolysis activation energy was the highest for cotton, 134.5 kJ × (mol∙K)−1, and the lowest for leather, 25.2 kJ × (mol∙K)−1. The DSC analysis showed that a number of transformations occurred during pyrolysis for each material. For each transformation, the normalized energy required for transformation, or released during transformation, was determined, and then summarized to present the energy balance. The study found that the energy balance was negative for only three waste materials—PET (−220.1 J × g−1), leather (−66.8 J × g−1), and chicken meat (−130.3 J × g−1)—whereas the highest positive balance value was found for potato peelings (367.8 J × g−1). The obtained results may be applied for the modelling of energy and mass balance of municipal solid waste pyrolysis.

Fuel Properties of Pongamia (Milletia pinnata) Seeds and Pods Grown in Hawaii

Pongamia, a leguminous, oilseed-bearing tree, is a potential resource for renewable fuels in general and sustainable aviation fuel in particular. The present work characterizes physicochemical properties of reproductive materials (seeds and pods) from pongamia trees grown in different environments at five locations on the island of Oahu, Hawaii, USA. Proximate and ultimate analyses, heating value, and elemental composition of the seeds, pods, and de-oiled seed cake were determined. The oil content of the seeds and the properties of the oil were determined using American Society for Testing and Materials and American Oil Chemist's Society methods. The seed oil content ranged from 19 to 33 wt % across the trees and locations. Oleic (C18:1) was the fatty acid present in the greatest abundance (47 to 60 wt %), and unsaturated fatty acids accounted for 77 to 83 wt % of the oil. Pongamia oil was found to have similar characteristics as other plant seed oils (canola and jatropha) and would be expected to be well suited for hydroprocessed production of sustainable aviation fuel. Nitrogen-containing species is retained in the solid phase during oil extraction, and the de-oiled seed cake exhibited enrichment in the N content, ∼5 to 6%, in comparison with the parent seed. The pods would need further treatment before being used as fuel for combustion or gasification owing to the high potassium and chlorine contents.

Pyrolysis kinetics and synergistic effect in co-pyrolysis of Samanea saman seeds and polyethylene terephthalate using thermogravimetric analyser

This work deals with co-pyrolysis of polyethylene terephthalate (PET) with Samanea saman seeds (SS) to understand the kinetics and synergistic effects between two different feedstocks. SS and PET were blended in different ratios (1:1, 3:1 and 5:1) and iso-conversional models such as Kissinger-Akahira-Sunose (KAS), Friedman method (FM), Starink (ST), Ozawa-Flynn-Wall method (OFW), and Coats-Redfern method (CR) were used to calculate the kinetic parameters. Results substantiate assumed hypothesis that blending of SS and PET at 3:1 provided higher synergistic effect and RMS value, which in turn indicated maximum formation of hot volatiles during pyrolysis. Kinetic analysis confirmed that individual SS and PET required higher activation energy while blended SS and PET at 3:1 ratio required lower activation energy to start the reaction. The thermodynamic and kinetic analysis confirmed that biomass had complex reaction kinetics which depends on reaction rate as well as its order.

Combustion behaviors of pileus and stipe parts of Lentinus edodes using thermogravimetric-mass spectrometry and Fourier transform infrared spectroscopy analyses: Thermal conversion, kinetic, thermodynamic, gas emission and optimization analyses

The combustion behaviors of both Lentinula edodes pileus (LEP) and stipe (LES) were characterized in response to four heating rates in the air atmosphere using thermogravimetric (TG)-mass spectrometry and TG-Fourier transform infrared spectroscopy analyses. There were two and three main peaks of the derivative TG curves for LEP and LES, respectively, with their main combustion stage occurring between 130 and 620 °C. Four iso-conversional models were compared to estimate activation energy values of their combustions. The main emission peaks of most gases ranged from 200 to 350 °C and from 500 to 600 °C for LEP and LES. Their comprehensive combustion parameters at 20 K/min (1.53 and 2.40 × 10^-6 %²/(min²·K³) for LEP and LES, respectively) as well as joint optimizations confirmed their great potential for bioenergy generation. The waste stream of LEP and LES could be well disposed through their combustions with a low level of air pollution.

Thermo-kinetics and product analysis of the catalytic pyrolysis of Pongamia residual cake

Catalytic fast pyrolysis of Pongamia residual cake (PRC) and the kinetics of this were evaluated using thermogravimetry and pyrolysis-gas chromatography/mass spectrometry analyses. The influence of the heating rate on the devolatilization process was studied to obtain corresponding kinetic information. Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) model-free isoconversion methods were used to predict the kinetic parameters. The major thermal degradation of PRC occurred around 150-550 °C with an activation energy of 97.2-394.3 kJ/mol or 114.5-412.2 kJ/mol as determined by the KAS and FWO methods, respectively. Micro-scale pyrolysis trials were performed to determine the effects of the PRC particle size, reaction temperature and PRC: catalyst weight ratio on the pyrolytic product distribution and upgraded pyrolytic vapor properties for the 5 wt% Ni impregnated on activated carbon (AC), aluminium(III) oxide (Al₂O₃), kaolin and zeolite NaA supports. The results indicated that using a 1:5 PRC: Ni/AC catalyst weight ratio with medium-sized PRC particles (125-425 μm) was the most effective condition for the conversion of oxygenated (O)-compounds to hydrocarbons (HCs) through decarbonylation, decarboxylation and dehydration reactions, giving the highest decrease (99%) in O-compounds. Increased HC yields, to more than 58%, were also obtained with this catalyst. Similarly, using the other synthesized Ni catalysts resulted in a reduction in the O-compounds and production of favorable HC species, albeit to a lesser extent. Therefore, the catalytic pyrolysis process of this residue, especially with a Ni/AC catalyst, has the potential to be a viable option for producing upgraded pyrolysis oil, which may be applied as a quality alternative biofuel.

Conversion of waste biomass and waste nitrile gloves into renewable fuel

The present study deals co-pyrolysis of neem seeds (NM) and waste nitrile gloves (WNG) in a semi-batch reactor with and without catalysts. Results confirmed that the yield of pyrolytic liquid was higher (43.52 wt% at NM: WNG ratio of 3:1) during thermal co-pyrolysis compared to that of catalytic co-pyrolysis (40.42 wt% and 37.14 wt% respectively with CaO and Al₂O₃ as catalysts). The use of catalysts increased the carbon content, acidity, and heating value and reduced the oxygen content, viscosity, and density of the pyrolytic oil. FTIR analysis suggested the presence of useful functional groups while ¹H NMR analysis confirmed high amounts of paraffin and aromatic compounds in the pyrolytic oil. GC-MS analysis of pyrolytic oil confirmed that blending of NM + WNG and use of catalysts reduced the oxygenated compounds and increased the alcohol and aldehyde thereby enhancing the fuel properties.

Evaluation of the potential of pelletized biomass from different municipal solid wastes for use as solid fuel

Four different municipal solid wastes (dog manure, horse manure, apple pomace waste and tea waste) and an industrial by-product (NovoGro) were used to produce solid fuel pellets. The mixtures followed a raw material to NovoGro ratio of 50:1. The pellets diameters varied between 4 and 5 mm, and the average length was 20 mm. The dog manure, horse manure, apple pomace waste and tea waste pellets were denoted as DN, HN, AN and TN, respectively. The combustion characteristics of the pelletized fuels were investigated, such as total moisture, ash content, calorific value and ash fusion point, etc. The physicochemical properties were analyzed by using a number of analytical techniques including X-ray fluorescence spectrometry (XRF), X-ray diffraction spectrometry (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results of the mechanical, thermal and morphological properties show that the raw materials were effectively combined with the NovoGro binder; furthermore, the DN, HN and TN pellets exhibited excellent mechanical and thermal properties, including high calorific values (>16.30 MJ/kg), high resistance to mechanical shock (>99%), high volatile matter contents, optimal softening temperatures and optimal ash contents. However, the high K, Ca, and Si contents of the AN can form low-melting-point eutectics, which can cause slagging. Moreover, the AN materials had large particle sizes, and high cellulose and hemicellulose contents led to high total moistures, low softening temperatures and low calorific values. The AN was not suitable for use as a fuel. The results suggested that NG is an effective binder for pelletization of biomass and showed the feasibility of using municipal solid wastes for energy production.

Pyrolysis kinetics and thermal behavior of waste sawdust biomass using thermogravimetric analysis

The present study reports pyrolysis behavior of three waste biomass using thermogravimetric analysis to determine kinetic parameters at five different heating rates. Physiochemical characterization confirmed that these biomass have the potential for fuel and energy production. Pyrolysis experiments were carried out at five different heating rates (5-25 °C min^-1). Five model-free methods such as Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (OFW), Friedman, Coats-Redfern, and distributed activation energy (DAEM) were used to calculate the kinetic parameters. The activation energy was found to be 171.66 kJ mol^-1, 148.44 kJ mol^-1, and 171.24 kJ mol^-1 from KAS model; 179.29 kJ mol^-1, 156.58 kJ mol^-1, and 179.47 kJ mol^-1 from OFW model; 168.58 kJ mol^-1, 181.53 kJ mol^-1, and 184.61 kJ mol^-1 from Friedman model; and 206.62 kJ mol^-1, 171.63 kJ mol^-1, and 160.45 kJ mol^-1 from DAEM model for PW, SW, AN biomass respectively. The calculated kinetic parameters are in good agreement with other reported biomass.

Optimization and characterization of hydrochar produced from microwave hydrothermal carbonization of fish waste

Fish processing results in large amounts of solid and liquid wastes that are unsustainably dumped into oceans and landfills. Alternative sustainable technologies that completely utilize seafood wastes are needed. Hydrothermal carbonization (HTC) that converts moisture-rich biomass into hydrochar is mostly employed for pure lignocellulosic biowaste. However, the suitability of HTC for pure non-lignocellulosic waste is unknown. Here, for the first time, a response surface design guided optimization of microwave hydrothermal carbonization (MHTC) process parameters, holding temperature (150-210°C) and time (90-120min), showed that a temperature of approximately 200°C and a time of approximately 119min yielded maximal hydrochar (∼34%). The atomic carbon and ash content, and calorific value of hydrochar were approximately 25-57%, 20-28%, and 19-24.5MJ/kg respectively, depending on the MHTC operating conditions. Taken together, these results confirm that MHTC produces hydrochar from fish waste of quality comparable to one produced from certain lignocellulosic, sewage and municipal wastes. Therefore, this strategy presents an exciting alternative technology that can be used either independently or in combination with other valorization techniques to completely utilize fish wastes irrespective of their quality.