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Hypothetical scenario of a sustainable biorefinery suggested to produce valuable biofuels coupled to municipal wastewater management
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A new opportunity for producing valuable biorefinery products can be found by integrating biochemical and thermochemical processing with municipal wastewater treatment. This study is the first to evaluate the kinetic triplet and thermodynamic parameters from the pyrolysis of typical Brazilian anaerobic sewage sludge performed in the framework of a...
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... The positive value of ΔG means that the pyrolysis reaction of BCS is not spontaneous; thus, the pyrolysis process requires additional energy for the conversion of biomass into various pyrolytic products. The ΔS values are used to qualitatively estimate the reactivity of the system [52]; in this research, an average value of −104.2 J/mol K was obtained. ...
This study is aimed at the analysis of the pyrolysis kinetics of Nanche stone BSC (Byrsonima crassifolia) as an agro-industrial waste using non-isothermal thermogravimetric experiments by determination of triplet kinetics; apparent activation energy, pre-exponential factor, and reaction model, as well as thermodynamic parameters to gather the required fundamental information for the design, construction, and operation of a pilot-scale reactor for the pyrolysis this lignocellulosic residue. Results indicate a biomass of low moisture and ash content and a high volatile matter content (≥70%), making BCS a potential candidate for obtaining various bioenergy products. Average apparent activation energies obtained from different methods (KAS, FWO and SK) were consistent in value (~123.8 kJ/mol). The pre-exponential factor from the Kissinger method ranged from 105 to 1014 min−1 for the highest pyrolytic activity stage, indicating a high-temperature reactive system. The thermodynamic parameters revealed a small difference between EA and ∆H (5.2 kJ/mol), which favors the pyrolysis reaction and indicates the feasibility of the energetic process. According to the analysis of the reaction models (master plot method), the pyrolytic degradation was dominated by a decreasing reaction order as a function of the degree of conversion. Moreover, BCS has a relatively high calorific value (14.9 MJ/kg) and a relatively low average apparent activation energy (122.7 kJ/mol) from the Starink method, which makes this biomass very suitable to be exploited for value-added energy production.
... When compared to biomass, a negative entropy score indicates that the product has a low level of unpredictability. The negative number implies that some structural modifications are required throughout the pyrolysis process to establish thermodynamic equilibrium [64]. Depending on the change in entropy, the speed of reaction kinetics and the approach to thermodynamic equilibrium may vary. ...
The goal of the research was to examine the thermal degradation of pomegranate peel to determine its pyrolytic behavior for bio-energy generation. Initial characterizations (proximate analysis, ultimate analysis, biochemical analysis, and higher heating value) were performed before thermal deterioration to ensure that it was suitable for the pyrolysis process. Later, in a thermo-gravimetric analyzer with inert gas, thermo-gravimetric studies were carried out from ambient temperature to 1000 °C at three distinct heating rates (15, 20, and 25 °C/min). Thermo-gravimetric measurements revealed that the greatest devolatilization occurred between 200 and 540 °C. Four iso-conversional models (FWO, KAS, Tang, and Starink) were used for kinetic and thermodynamic analysis. The results revealed that the average activation energies were found 137.79, 149.63, 168.47, and 163.97 kJ/mol for FWO, KAS, Tang, and Starink model, respectively. The potential energy barrier (~ 4–8 kJ/mol) between activation energy and reaction enthalpy demonstrated favorable circumstances for product formation. Average Gibbs free energy change (∆G) for pomegranate peel by using iso-conversional FWO, KAS, Tang, and Starink model was found to be 81.84, 145.54, 80.53, and 80.83 kJ/mol, respectively. Thus, kinetic and thermodynamic data demonstrated that pomegranate peel had sufficient bioenergy potential.
Graphical abstract
... The Eα can be appropriately estimated from non-isothermal thermogravimetric data using isoconversional methods, and the A is determined from the master plot method, which is one of the reliable mathematical methods recommended by the Kinetics Committee of the International Confederation of Thermal Analysis and Calorimetry (ICTAC) [10,15]. Knowing these parameters helps predict, simulate, and optimize the complex thermal decomposition process reactor for calculating energy balances and determining the viability of the thermochemical conversion process [14,16]. The evaluations of the kinetic parameters of the HTC process are complicated by data acquisition during the process; this has led many authors to develop different types of kinetic studies of the HTC process. ...
... The value of ΔS is a qualitative measure to estimate the reactivity of the system [16]. The ΔS values in Fig. 9 for the FWO and KAS method are negative at all values of α. ...
This study proposed the use of the kinetic triplet analysis and thermodynamic parameter determination to investigate the hydrothermal carbonization (HTC) of cocoa shell (CS) for energy production. The variations in the Eα were determined by model-free isoconversional methods, the A values were determined using the ASTM E698-18 kinetics approach, and for f(α), the master plot methods were used. A progressive variation of Eα values was found, revealing competitive or consecutive reactions during HTC process, as well as multiphasic biomass conversion. From the master plot method, the experimental curve of CS does not perfectly match a single theoretical curve, indicating different reaction mechanisms during the HTC process. However, over the entire conversion range, the n-order reaction model (n = 1.25) adequately describes the experimental behavior (R² > 0.995). Furthermore, this value of n = 1.25 may imply a relatively low collision probability and can be related to the high extractives and lignin content in CS. Furthermore, for specific values of α, the difference between Eα and ΔH was lower than 3.98 kJ/mol indicating the facility to convert CS to hydrochar. In addition, the ΔS values showed that the process reaches thermodynamic stability during the conversion of CS. Finally, hydrochar characterization showed an energy densification of 40.30% in the case of hydrochar produced at 250 °C, thus demonstrating the feasibility of using this type of biomass for energy purposes.
Graphical abstract
... The isoconversional methods can precisely estimate the activation energy of biomass pyrolysis, but they cannot accurately calculate the pre-exponential factor and reaction model [23,25]. Taking this into account, methods of compensation effect and the master plot can be employed to calculate the pre-exponential factor and reaction model, respectively [26]. ...
The freshwater alga Spirogyra crassa was subjected to pyrolysis to investigate its potential use as a bioenergy feedstock. To do so, the pyrolysis behavior of the Spirogyra crassa under thermogravimetric scale was first determined at the temperature range from 25 to 800 °C, with three slow heating rates (5, 10, and 20 °C min−1) under an oxygen-free atmosphere. It is assumed that the pyrolysis of Spirogyra crassa occurs in four reaction steps with different kinetic triplets. The activation energy was obtained for each reaction step by concurrent use of four isoconversional methods (Friedman, Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose, and Starink), with average values ranging from 120.6 to 217.0 kJ mol−1. Pre-exponential factors determined from the kinetic compensation effect were found to range between 6.88×107 and 7.54×1019 min−1. Master plot results indicated that the nth-order-based mechanisms described the pyrolysis behavior of organic matter and, subsequently, the pyrolysis behavior of inorganic matter follows Avrami-Erofeev nucleation mechanisms. According to the thermodynamics parameters, the pyrolysis of Spirogyra crassa verifies to be a non-spontaneous, endothermic, and complex conversion. The summative kinetic expression proposed from the estimated kinetic triplets is a satisfactory option for describing the pyrolysis kinetics of Spirogyra crassa, with a quality of adjustment above 93.3 %. In conclusion, the insights of this study confirm that Spirogyra crassa has considerable potential as a feedstock for bioenergy production, and could be used for engineering purposes in the design or simulation of large-scale pyrolysis reactors.
... Recently, the thermochemical conversion of biomass has been receiving attention due to its attractive bioenergy generation [11,12]. Gasification is one of the most promising conversion processes to provide energy and chemicals from the diverse feedstock. ...
The gasification of agro-industrial residues has been identified as a viable alternative for energy generation, acting simultaneously as a solution for the final disposal of these wastes. Knowing the kinetics of the gasification reaction is crucial to the comprehension of the mechanisms and the phenomena involved in the process, and the development and optimization of industrial gasifiers. Accordingly, this study aims to examine, based on four kinetic models, the CO2 gasification behavior of three biomass chars prepared from apple pomace, spent coffee grounds and sawdust, and to associate the results with differences in the ash composition of the samples. The biochars were obtained from pyrolysis under N2, in a fixed-bed tubular quartz reactor, with an average heating rate of 12 K min⁻¹ and a residence time of 60 min at the final temperature of 873 K. Biochars were isothermally gasified in a thermogravimetric analyzer with CO2, at atmospheric pressure, at temperatures of 1033, 1083 and 1133 K, in the kinetically controlled regime. From the characterization of raw biomasses, it was found that the apple pomace had the highest amount of potassium, and its biochar was the most reactive. Also, it was observed an increase in the gasification rates in the higher conversion region for all biochars. Concerning these reactivity profiles, the inorganic components were more important to the gasification behavior than the biomass lignocellulosic matter. For all biochars, the semi-empirical modified random pore model (MRPM) was the best-fitted model, indicating its suitability to CO2 gasification and confirming the catalytic influence of the inorganic matter in the studied samples. After demineralization, biomass chars presented higher values of activation energy and pre-exponential factor. According to the MRPM model, activation energy values within the range of 161.5–187.2 kJ mol⁻¹ and 232.1–240.2 kJ mol⁻¹, respectively, were obtained for the CO2 gasification of regular biochars and demineralized biochars.
Graphical abstract
... The dried anaerobic sludge can be converted into biochar, bio-oil, and bio-syngas using a pyrolysis reactor. The energy contained in biosyngas and bio-oil can be exploited using a CHP system or a dual combustion system, and biochar can be used as a soil additive in agriculture [161]. Figure 1 represents a schematic configuration of this approach. ...
Anaerobic digestion is a well-known technology with wide application in the treatment of high-strength organic wastes. The economic feasibility of this type of installation is usually attained thanks to the availability of fiscal incentives. In this review, an analysis of the different factors associated with this biological treatment and a description of alternatives available in literature for increasing performance of the process were provided. The possible integration of this process into a biorefinery as a way for producing energy and chemical products from the conversion of wastes and biomass also analyzed. The future outlook of anaerobic digestion will be closely linked to circular economy principles. Therefore, this technology should be properly integrated into any production system where energy can be recovered from organics. Digestion can play a major role in any transformation process where by-products need further stabilization or it can be the central core of any waste treatment process, modifying the current scheme by a concatenation of several activities with the aim of increasing the efficiency of the conversion. Thus, current plants dedicated to the treatment of wastewaters, animal manures, or food wastes can become specialized centers for producing bio-energy and green chemicals. However, high installation costs, feedstock dispersion and market distortions were recognized as the main parameters negatively affecting these alternatives.
Seaweeds are essential autotrophs in the marine environment, resembling submerged forests near shorelines that provide habitats for various organisms. They have now become a significant source of numerous bio-products and are cultivated and harvested in various regions worldwide, contributing to the burgeoning blue economy. Environmentally friendly utilization of marine resources is one solution to meet the increasing demand for bioenergy and bio-products in the advancing blue economy. In this study, we investigated the bioenergy potential of the brown macroalgae Dictyota dichotoma using the slow pyrolysis technique. The pyrolysis process was conducted at three different heating rates (5, 10, and 20 °C min⁻¹) in an inert nitrogen gas atmosphere, starting from room temperature and reaching 800 °C. Four valorization stages were identified, and the data obtained were fitted to various model-free iso-conversional methods, namely Friedman, Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose, and Starink. The calculated activation energies ranged from 157.32 to 185.71 kJmol⁻¹. The pre-exponential factor, determined from the kinetic compensation effect for the valorization processes, fell within the range of 4.8 × 10⁸ to 6.5 × 10¹⁷ min⁻¹. This range demonstrated the thermal conversion of both bioorganic and inorganic molecules, encompassing the relevant reactions throughout the entire process. Analysis using a master plot indicated that the pyrolysis of brown macroalgae primarily follows a diffusion-based process. The reproducibility of the data was further confirmed by fitting the experimental parameters obtained during the simulation process. The thermodynamic analysis revealed values of enthalpy (ΔH) ranging from 146.85 to 179.72 kJmol⁻¹ and values of Gibbs free energy (ΔG) ranging from 143.91 to 288.19 kJmol⁻¹. These findings demonstrate the endothermic and non-spontaneous behavior of seaweed biomass pyrolysis reactions. The entropic values indicated the formation of more ordered molecules during the latter three-pyrolysis stages. Overall, the results highlight the suitability of Dictyota seaweed biomass as a promising feedstock for bioenergy generation, contributing to the development of the blue economy.
In this study, soybean stalk (SS) biomass was explored for its bioenergy generation prospective by thermal degradation. Proximate, ultimate, HHV (higher heating value), and thermogravimetric (TG) analyses were performed. For TG, three heating rates (10, 15, and 25 °C/min) in nitrogen atmosphere with temperature from room temperature to 800 °C were chosen. TG experiments affirmed that maximal devolatilization occurred between 205 and 510 °C. Four iso-conversional models (Friedman, Flynn–Wall–Ozawa (FWO), Kissinger–Akahira–Sunose (KAS), and Starink) were employed for kinetic and activation energy evaluation. Values of activation energy using these models came out to be 127.62, 124.15, 124.44, and 136.28 kJ/mol, respectively. Results of the FWO model were used for thermodynamic evaluation. Average values of change of enthalpy (∆H) and Gibbs free energy (∆G) were found to be 124.29 and 167.23 kJ/mol, respectively. The pre-exponential factor (A) values lie in the range of 10⁵–10¹³ s⁻¹. Master plots and Criado method indicated complex reaction mechanism during pyrolysis. Comprehensive pyrolysis index (CPI) affirmed that a higher heating rate is favorable for SS pyrolysis. The results of physicochemical, kinetics, thermodynamics, and pyrolysis performance index reflected high bioenergy potential of SS which emphasized that pyrolysis of SS is a pragmatic approach for affordable, sustainable, and green-clean energy production.
Biorefineries play an important role in the sustainability, and therefore in the biobased economy. Some of challenge related with policy regulation, new process, and raw materials, needs structural change in the value chain such as logistic, discover new raw materials and overcome troubles arose from pandemic SARS Cov 2. It was evident the needs to have autosustainable economy, the active participation of quadruple helix efforts to drive new developments and reach new milestones in technological maturity.
Examples where government efforts have facilitated the legal framework for the operation of Research Centers with social projection in Costa Rica, have allowed for example to join the developments of nanotechnology to one of the lines of biorefineries where pineapple waste has been taken advantage of. On the other hand, advances in this sense in Uruguay and Chile have allowed substantial advances in the use of residues from the meat industry and the production of polyhydroxyalkanoates, respectively. Undoubtedly, Brazil is experiencing an important boom in the Latin American economy given its long history in the use of agricultural residues and in obtaining biofuels. Colombia is positioned as an important international actor due to its contributions and the adoption of the 2030 bioeconomy agenda and the governmental impulse through the 2030 bioeconomy mission for Colombia, which requires the cohesion of the actors from the different industrial sectors, the academia, the state and civil society. In this sense, initiatives developed in post-conflict areas in Colombia for the reconstruction of the social fabric and to provide new energy sources and biobased products from organic agricultural and agro-industrial residues in the Colombian Caribbean are also presented. With the aim to do a prospective analysis of the state of biorefineries in Latin America, this work was divided in the following section.
TABLE OF CONTENTS
1. Bioeconomy and Biorefinery concept
2. Bioeconomy and Biorefinery Public Policy
3. New and old raw materials
4. Building Blocks molecules
4.1 Furan dicarboxylic acid (FDCA)
4.2 Furfural
4.3 Hydroxypropionic acid
4.4 Lactic acid
4.5 Ethanol
4.6 Four Carbon 1,4-Diacids (Succinic, fumaric and malic)
4.7 Biohydrocarbons: Isoprene
4.8 Levulinic acid (LA)
4.9 Sorbitol
4.10 Xylitol
5. Raw materials integration
6. Energy integration
7. Non-conventional biobased materials
8. International market and future challenges
9. Final remarks
10. Acknowledgments
11. References
Fossil fuels are currently the most significant energy sources. They are expected to become less available and more expensive, leading to a great demand for energy conservation and alternative energy sources. As a sustainable and renewable energy source, Biomass has piqued interest in generating bioenergy and biofuels over
recent years. The thermal conversion of biomass through pyrolysis is an easy, useful, and low-cost process that can be applied to a wide variety of feedstocks. Pyrolysis characteristics of different feedstock samples can be analyzed and examined through thermogravimetric analysis (TGA). TGA has been an essential tool and widely used to investigate the thermal characteristics of a substance under heating environments, such as thermodegradation dynamics and kinetics. Studying the potential of waste biomass for generating sustainable bioenergy carves a pathway into a circular bioeconomy regime, and can help tackle our heavy reliance on nonrenewable energy sources. This study aims to give a deep insight into the wide use of TGA in aiding in the research and development of pyrolysis of different waste biomass sources. The thermal characteristics portrayed by different biomass wastes through TGA are discussed. The effects of significant pyrolysis operating parameters are also illustrated. A more comprehensive understanding of evolved products during the pyrolysis stage can be gained by combining TGA with other analytical methods. The pros and cons of using TGA are also outlined. Overall, an indepth
literature review helps identify current trends and technological improvements (i.e., integrating artificial intelligence) of TGA use with pyrolysis.
