Thermochemical Conversion Processes Research Articles

Review on Fast Pyrolysis of Biomass for Biofuel Production from Date Palm

The fast depletion of fossil fuels and growing concerns about environmental sustainability have increased interest in using biomass as a renewable energy source. Fast pyrolysis, a thermochemical conversion process, has emerged as a promising technique for converting biomass into valuable biofuels and bio-based chemicals. The aim of this literature review is to comprehensively analyze recent advances in biomass fast pyrolysis, focusing on the principles, process parameters, product yields, and potential applications of biomass fast pyrolysis. This comprehensive review, based on an in-depth analysis of 61 scientific papers and 4 patents, provides an overview of various biomass technologies (combustion, gasification, pyrolysis) used for biofuel production. It focuses on the principles, benefits and applications of these technologies and serves as a valuable resource for researchers, engineers and policy makers. Based on the wealth of information from rigorously selected sources, we explore the key process parameters and reactor types associated with each technology, providing insight into its efficiency and product composition.

Biomethanol production from renewable resources: a sustainable approach.

The abundant availability of various kinds of biomass and their use as feedstock for the production of gaseous and liquid biofuels has been considered a viable, eco-friendly, and sustainable mode of energy generation. Gaseous fuels like biogas and liquid fuels, e.g., bioethanol, biodiesel, and biomethanol derived from biological sources, have been theorized to produce numerous industrially relevant organic compounds replacing the traditional practice of employing fossil fuels as a raw material. Among the biofuels explored, biomethanol has shown promising potential to be a future product addressing multifactorial issues concerning sustainable energy and associated process developments. The presented mini-review has explored the importance and application of biomethanol as a value-added product. The biomethanol production process was well reviewed by focusing on different thermochemical and biochemical conversion processes. Syngas and biogas have been acknowledged as potential resources for biomethanol synthesis. The emphasis on biochemical processes is laid on the principal metabolic pathways and enzymatic machinery involved or used by microbial physiology to convert feedstock into biomethanol under normal temperature and pressure conditions. The advantage of minimizing the cost of production by utilizing suggested modifications to the overall process of biomethanol production that involves metabolic and genetic engineering in microbial strains used in the production process has been delineated. The challenges that exist in our current knowledge domain, impeding large-scale commercial production potential of biomethanol at a cost-effective rate, and strategies to overcome them along with its future scenarios have also been pointed out.

A Review on Advanced Processes of Biohydrogen Generation from Lignocellulosic Biomass with Special Emphasis on Thermochemical Conversion

The utilization of lignocellulosic biomass as an alternative energy source presents a promising opportunity to achieve a future energy system that is clean and free from CO2 emissions. To realize this potential, it is crucial to develop effective techniques for converting biomass and organic solid waste into secondary energy sources. Among the available options, hydrogen production stands out due to its numerous advantages, including its cleanliness, versatility in conversion and utilization technologies, high energy efficiency, and dense energy content per unit weight. This article offers a comprehensive overview of different conversion pathways and important technologies for generating hydrogen from biomass and organic solid waste. It specifically focuses on the thermochemical conversion process, which shows promise as an economically viable approach. While certain thermochemical conversion processes are still in the developmental phase, utilizing organic biomass for hydrogen production is widely recommended due to its ability to yield higher amounts of end products and its compatibility with existing facilities. However, it should be noted that this method necessitates a substantial amount of energy due to its endothermic nature. This article also explores alternative hydrogen conversion technologies and their potential for utilizing organic biomass as a feedstock, while addressing the challenges and limitations associated with these methods.

Coal-derived synthetic natural gas as an alternative energy carrier for application to produce power --- comparison of integrated vs. non-integrated processes

This work addresses clean utilization of coal through thermo-chemical processes (i.e., gasification & methanation) that convert solid carbonaceous feedstock to gaseous fuel for power generation, which features potential advantages for environmental benignity and energy security. It would be beneficial to convert coal to synthetic natural gas (SNG) that can feed the combined cycle units in the regions like Taiwan where natural gas (NG) is imported, which would help stabilize the price of electricity and alleviate the energy security concern. The objective of this study is to investigate the performance as well as the pros and cons between integrated and non-integrated SNG plants. The characteristics of power and chemical plants differs in various aspects, thus the concept of non-integrated approach to produce SNG and power offers better system resilience, availability and market flexibility at the expense of reduced efficiency. Fuel switch strategy would be one of the key pillars for the pathway toward Net-Zero Emissions (NZE) by 2050. Alternative energy carriers (AECs), generally synthesized from conversion of other energy sources, may provide solutions to decarbonization and low-emission environment. In summary, the thermo-chemical conversion processes studied in the present work address the core issues in clean and efficient utilization of carbonaceous resources.

Pyrolysis of Aloe vera leaf wastes for biochar production: Kinetics and thermodynamics analysis

The large waste potential of biomass, which is used extensively industrially, is a problem that needs to be solved both environmentally and economically. In this context, the conversion of these wastes into valuable solid products by thermochemical conversion processes is considered a very important alternative. In this study, it was aimed to examine the pyrolytic behavior of Aloe vera leaf waste, determine the pyrolysis kinetic parameters and characterize the biochar obtained as a result of pyrolysis at different temperatures. The pyrolytic behavior of this waste at temperatures between 25 and 600 °C and heating rates of 5, 10, 20 and 40 °C min−1 were investigated by thermogravimetric method. The pyrolysis kinetic parameters of these wastes were calculated using the Kissinger-Akahira-Sunosa (KAS) and Flynn-Wall-Ozawa (FWO) methods. According to the results obtained, the pyrolysis of Aloe vera waste took place in 3 stages (moisture removal, devolatilization and char formation) and approximately 65% of the mass was removed from the structure. The activation energy values calculated by KAS and FWO methods for the devolatilization and char formation stages were found to be approximately 185 kJ mol−1 and 335 kJ mol−1, respectively. According to the kinetic and characterization results obtained, it has been understood that Aloe vera leaf wastes are a very suitable source for biochar production and biochar obtained can be evaluated in different areas such as adsorption, agriculture and combustion.

A review on in-situ process analytical techniques for the thermochemical conversion of coal and biomass

Abstract Coal and biomass are important feedstocks for carbon energy from thermochemical conversion process. Fully understanding the analytical technology that characterizes the changes in physicochemical properties and structural characteristics of coal and biomass during the thermochemical reactions is a key prerequisite for the realization of appropriate utilization of energy fuels. Modern in-situ process analysis technology can accomplish the in-situ detection of the experimental process, and therefore reflect the experimental process more accurately. Moreover, it is developing towards automation, intelligentization, and comprehensive detection. Based on the characteristics of each detection technology, this paper summarizes the basic principles, application scope and performance characteristics of the three advanced in-situ process analysis technologies: hyphenated technology, synchrotron radiation, and online analysis. The practicability and accuracy of each detection technology in coal and biomass research are compared and analyzed, and its latest application and development trend are elucidated. These tools not only make up for the shortcomings of traditional detection techniques in characterizing the in-situ reaction, but also provide complementary information on molecular microscopic changes during fuel thermal conversion. This review paper can provide insights for relevant researchers in the selection of analytical techniques, and promote in-depth study on microcosmic mechanism of fuel conversion.

Isoconversional thermal decomposition reaction kinetics of oil palm trunk and rubberwood sawdust for thermochemical conversion processes.

Biomass as a raw material has profound implications for thermal conversion processes. It is important to study the relationship between kinetic modeling to depict significant importance in thermal processing by estimating volatile yield and reaction performance during biomass decomposition. This work aimed to determine the thermal decomposition reaction kinetics of non-woody (oil palm trunk (OPT)) and woody (rubberwood sawdust (RWS)) biomass. Devolatilization of biomass is determined by the thermogravimetric analysis (TGA) at three different heating rates (10, 20, and 30 °C/min) using nitrogen as inert gas. The kinetic analysis used isoconversion models of Friedman, Ozawa-Flynn-Wall (OFW), and Kissinger-Akahira-Sunose (KAS). The activation energy varied from 218.4 to 303.8 kJ/mol (Friedman), 235.9 to 299.1 kJ/mol (OFW), and 235.8 to 298.9 kJ/mol (KAS) for OPT; and 199.7 to 228.1 kJ/mol (Friedman), 210.6 to 225.6 kJ/mol (OFW), and 210.7 to 225.2 kJ/mol (KAS) for RWS. The kinetic analysis indicated that RWS and OPT had diverse reaction kinetics, which depend on the reaction rate and order of the reaction. Experimental and theoretical conversion data agreed reasonably well, indicating that these results can be used for future OPT and RWS process modeling. Consistency of results is validated using GC-MS equipped with a pyrolyzer.

Experimental Study of the Combustion of and Emissions from Olive and Citrus Pellets in a Small Boiler

Agro-industrial activities generate a great amount of bioproducts as biomass residues containing energy and with potentially useful applications in the thermochemical conversion process. The management of this feedstock as uncontrolled combustion (“open burning”) can often be a problem within the supply chain for disposal practices, both in environmental and economic aspects. The residual matrices from agroforestry biomass processing can be treated to increase their energy levels and economic value. A widespread practice for sustainable disposal is the production of pellets from residual biomass, such as pruning. The aim of this study is to explore the combustion of pellets obtained from olive and citrus pruning, and their emissions into the atmosphere. This study confirms the possibility of using waste biomass to obtain a high-energy biofuel that is usable in a controlled combustion system and to monitor the process and its related emissions (CO, CO2, NOx, SO2, PM). Three different pellets (olive pellet, citrus pellet and a pellet obtained from a mix of olive and citrus) were characterized to determine their physicochemical properties and burned in an 80 kWth boiler equipped with multicyclone filter bags as an abatement system to evaluate relative emission. The characterization results show that citrus pellet has a higher ash content, moisture content and lower energy value than mixtures of olive pellet. The emission results suggest that, during combustion, higher emissions of CO and SO2 were monitored from mixtures of citrus pellet compared to burning only olive pellet.

Thermal and Catalytic Pyrolysis of Real Plastic Solid Waste as a Sustainable Strategy for Circular Economy

ABSTRACT The management of plastic waste is a serious environmental problem, therefore numerous strategies have been explored to reuse/recover these materials, avoiding their disposal in landfills. In particular, research has focused on thermochemical conversion processes and especially on pyrolysis processes. Therefore, in this study, a real Plastic Solid Waste (PSW) from COREPLA (Italian national consortium for collection, recycling, and recovery of plastic packaging), deprived of PET, PVC, and PTFE was used as feedstock for batch thermal and catalytic pyrolysis tests. The experiments were performed in a micro-reactor under nitrogen flow, using ɣ-alumina as catalyst. The effects of a variation in pyrolysis temperature (450–650°C) on the gaseous, condensable, and solid products were assessed. The thermal and catalytic pyrolysis tests of LDPE at 550°C were also investigated, as a representative surrogate of the plastics materials found in PSW. Preliminary results highlight that gas and condensate yields increase with pyrolysis temperature (with or without γ–alumina). The condensate products of all experiments were an oily wax made up mainly of long-chain aliphatic hydrocarbons (mostly diesel-like fraction, C12-C20). The qualitative composition of gaseous and condensable products differs between thermal and catalytic tests. However, the alumina leads to a higher formation of aromatic hydrocarbons.

Toward circular economy for pomegranate fruit supply chain under dynamic uncertainty: A case study

Food security is a fundamental prerequisite of human survival. This study focuses on providing a novel bi-objective model for the design of a green closed-loop pomegranate supply chain based on the value chain. To maximize the benefits of circular economy, we propose a thermochemical conversion process and develop a novel hybrid risk-neutral and risk-averse multi-stage stochastic programming (RNRAMSSP) approach to cope with supply uncertainty. We employ the expected value of perfect information (EVPI) and value of stochastic solution (VSS) to validate the proposed approach. For the VSS metric, we define a novel measure to compare the worst-case cost of the stochastic and deterministic model solutions. To demonstrate the applicability of the proposed model, we provide a real case study in Iran. Based on the VSS metric, the risk-neutral and risk-averse stochastic model solutions save up to 1% and 1.76% in the worst-case cost, respectively, compared to the deterministic model.

Syngas Production from Protective Face Masks through Pyrolysis/Steam Gasification

The COVID-19 pandemic has caused a heavy expansion of plastic pollution due to the extensive use of personal protective equipment (PPE) worldwide. To avoid problems related to the entrance of these wastes into the environment, proper management of the disposal is required. Here, the steam gasification/pyrolysis technique offers a reliable solution for the utilization of such wastes via chemical recycling into value-added products. The aim was to estimate the effect of thermo-chemical conversion temperature and steam-to-carbon ratio on the distribution of gaseous products obtained during non-catalytic steam gasification of 3-ply face masks and KN95 respirators in a fluidized bed reactor. Experimental results have revealed that the process temperature has a major influence on the composition of gases evolved. The production of syngas was significantly induced by temperature elevation from 700 °C to 800 °C. The highest molar concentration of H2 gases synthesized from both types of face masks was estimated at 800 °C with the steam-to-carbon ratio varying from 0 to 2. A similar trend of production was also determined for CO gases. Therefore, investigated thermochemical conversion process is a feasible route for the conversion of used face masks to valuable a product such as syngas.

THERMOCHEMICAL CONVERSION OF SUNFLOWER HUSKS

The article presents the results of experimental studies of the process of thermochemical conversion of sunflower husk by pyrolysis at a temperature of 550 °C and heating rate of 10 °C/min. The main physico-chemical characteristics of this plant raw material correspond to commercial fuels. Ashes are dominated by potassium (38.7%), calcium (26.9%) and iron (13.6%) oxides. Thermochemical conversion of sunflower husks produces 56.49% of pyrolysis liquid, 29.26% of carbonaceous residue and 14.25% of gas. Experimental data of pyrolysis fluid viscosity dependence on temperature in the range from –6 to +23.5 °С were obtained. As a result of GC-MS analysis mass spectra of 90 substances of organic nature were obtained, of which 20 were identified, which corresponds to 77.3% of the entire fraction. Pyrolysis fluid contains acids, alcohols, esters, ketones, amides, aldehydes, alkenes, phenols. Taking into account boiling points of the components included in the liquid fraction, it was found that it is reasonable to extract acetic acid and methyl alcohol. The acetic acid content in the pyrolysis liquid under study reaches 31.98% and the methanol content 12.05%. It should be noted that the content of propanoic acid, 2-oxo-, ethyl ester (6.20%) is high enough, but its boiling point coincides with a number of other components, so distillation of this component is inexpedient. Thus, the obtained pyrolysis liquid is a source of raw materials for obtaining at least two high added value products.

Study on solar-driven methanol steam reforming process in parabolic trough solar receiver-reactors by developing an optical-thermal-chemical model of realistic porosity distributions

The catalyst particle packing characteristics have a significant impact on improving the comprehensive energy conversion performance and economic benefits of sustainable solar-driven thermochemical hydrogen production systems. However, corresponding accurate and efficient numerical research tools or methods still need to be developed. In this paper, a three-dimensional comprehensive optical-thermal-chemical coupling model with catalyst particle packing characteristics is proposed for the parabolic trough solar receiver-reactor (PTSRR) of methanol steam reforming reaction (MSRR) for hydrogen production. This model is developed by combining a Monte Carlo ray tracing optical model, a computational fluid dynamics model, a MSRR comprehensive kinetic model with a Blender rigid body packing model. After validation, it was found from comparisons with previous studies that this model can represent relatively realistic catalyst porosity distributions of packed-bed reactors at a very low computational cost. Then, this model was applied to obtain the porosity of different PTSRR-MSRRs and optimize the catalyst size and shape, to achieve better comprehensive performance as well as economic benefits of higher overall efficiency and catalyst utilization efficiency. The results reveal that the PTSRR-MSRRs filled with cylinders and Raschig rings (R-PTSRR) can achieve similar high methanol conversion rate, while the R-PTSRR has more advantages with its lower average resistance coefficient and CO selectivity. After weighing the methanol conversion rate, the overall efficiency and the catalyst utilization efficiency, the optimum R-PTSRR is highly recommended. This study provides a useful option for rapid comprehensive analysis and optimization of similar solar-driven thermochemical conversion processes on catalyst particle packed beds.

Integration of thermochemical conversion processes for waste-to-energy: A review

Integration of thermochemical conversion processes for waste-to-energy: A review

Formation and transformation of mineral phases in biomass ashes and evaluation of the feedstocks for application in high-temperature processes

Biomasses are known for their variety of ash systems, often accompanied by limiting effects such as fouling, sintering, slagging, agglomeration and corrosion, which affect thermochemical conversion processes (combustion, gasification, pyrolysis etc.). To explore those limiting effects, five different feedstocks from agricultural, woody, and processed biomasses are investigated after ashing in a temperature range between 200 and 815 °C. The ash composition and their specific distribution inside the particles are studied using X-ray fluorescence (XRF) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). Distinct differences are detected in the ashes from various biomasses, indicating that the ash systems can be homogeneous (mainly authigenic origin) or heterogeneous (with significant contributions of detrital/technogenic origin). Using X-ray diffraction (XRD), the formation and transformation of mineral phases are monitored in the ashes produced at various temperatures. The data are then compared to the results of thermochemical calculations. The experimental findings agree almost completely with those calculated using the FactSage™ software package. In connection with the identified mineral phases, the release behavior of the main alkali species, potassium, is monitored as a function of the ashing temperature. Based on these results indicating the ashes' mineral phase composition and their observed heterogeneity, the high-temperature behavior of the ash fusion temperatures (AFT) and ash fusion interval (AFI) between deformation and flow temperature can be ascertained. Finally, based on their ashing behavior, the biomasses’ potential use in thermochemical conversion processes at high temperatures is evaluated.

Potential Usage of Selected Agro-Residue as a Biofuel Production Sources: Physiochemical Evaluation Approach

This article present physiochemical characterization of commonly available agricultural waste residues on dry basis for: (Corn cob, Coconut shell, Cashew nut, Palm kernel shell and Cassava stem) with the view to evaluate their respective suitability for biofuel production using thermochemical conversion process. The investigated respective biomass feedstock milled samples was analyzed in the laboratory for fuel physiochemical characterization. The physiochemical characterization carried out on each biomass waste sample are Proximate Analysis, Ultimate Analysis, Elemental composition analysis and determination of their respective Higher heating Value(HHV). The obtained results revealed that of all the biomass samples characterized, the Coconut shell (CNS), Corn cob(CC) and Cassava stem(CS) samples proved to possess the most suitable characteristics for better bio-oil production. Palm kernel shell(PKS), Coconut shell(CNS) and Cashew nut(CN) due to their obtained low ash content, adequate hardness and fairly high fixed carbon content are generally regarded to be a potential source for making quality grade charcoal (bio-char) using Pyrolysis process. Gasification process is found desirable to producing high yield of bio-gas for Corncob(CC) and Cassava stem(CS) biomass samples due to their respectively obtainable high value of moisture content: (13.4%wt and 15.10%wt.) and fixed carbon contents of (67.94%wt and 74.13%wt) in this study. Moreover, among all other biomass sample investigated in this study, Coconut Shell(CNS) in comparison to all other samples characterized attained highest HHV of 31.2 MJ/kg. Negligible amount of Sulphur and Nitrogen which could resulted to lower emission of SO2 and NO2 if use directly for heating purposes aftermath application of any of the thermochemical conversion processes is also observed for the biomass waste samples analyzed independent of their types. These results show that the characterized biomass samples could be a suitable candidate for alternative energy fuels production in terms of quality and environment concern.

A Comprehensive Study on the Combustion of Sunflower Husk Pellets by Thermogravimetric and Kinetic Analysis, Kriging Method

The combustion of sunflower husk pellets was investigated by kinetic analysis supplemented by the Kriging method. The nonisothermal thermogravimetric experiments in air were carried out at the temperatures from 20 to 700 °C and heating rates of 5, 10, and 20 °C/min. Kinetic analysis was carried out using the model-free OFW (Ozawa–Flynn–Wall) method and Coats–Redfern (CR) method. The activation energy values, calculated by the OFW method, ranged from 116.44 to 249.94 kJ/mol. These data were used to determine the combustion mechanism by the CR method. The kinetic triplet (Eα, A, g(α)) was determined in the conversion interval 0.2 to 0.8. The model of the chemical reaction F8 was recommended to describe the mechanism of the thermochemical conversion process. The relationship between the kinetic parameters was analyzed using the Kriging method. The patterns between the kinetic parameters were represented as three-dimensional surfaces and two-dimensional projections. The distribution’s surfaces were uniform; there were local extremes as well as linear regions. A new approach to the data analysis will allow predicting parameters of a thermochemical conversion of the various raw materials and contributes to a deeper understanding of the characteristics and mechanism of biomass combustion.

Optimization-Driven Machine Learning Approach for the Prediction of Hydrochar Properties from Municipal Solid Waste

Municipal solid waste (MSW) management is an essential element of present-day society. The proper storage and disposal of solid waste is critical to public health, safety, and environmental performance. The direct recovery of MSW into useful energy is a critical task. In addition, the demand for conventional power supplies is high. As a strategy to solve these two problems, the technology to directly convert municipal solid waste into conventional energy to replace fossil fuels has been obtained. The hydrothermal carbonization (HTC) process is a thermochemical conversion process that utilizes heat to convert wet biomass feedstocks into hydrochar. Hydrochar with premium gasoline properties is used for fuel combustion for strength. The properties of fuel hydrochar, including C char (carbon content), HHV (higher heating value), and yield, are mainly based on the properties of the MSW. This study aimed to predict the properties of fuel hydrochar using a machine learning (ML) model. We employed an ensemble support vector machine (E-SVM) as the classifier, which was combined with the slime mode algorithm (SMA) for optimization and developed based on 281 data points. The model was primarily trained and tested on a fusion of three datasets: sewage sludge, leftovers, and cow dung. The proposed ESVM_SMA model achieved an excellent overall performance with an average R2 of 0.94 and RMSE of 2.62.

The utilization of rice straw (Oryza Sativa L.) as a green catalyst in the enhanced production of hydrogen via the thermochemical conversion process of shrimp farm sludge

The catalytic mechanism of rice straw, Oryza Sativa L., on the carbonation of shrimp farm sludges via the gasification process was investigated in this work. Rice straw possessed 75% of its weight is silicon dioxide (SiO2) which can be utilized as an effective catalyst whereas the tar decomposition and gas production during the thermochemical process can be enhanced. In that manner, the influence of working temperature (oC), the ratio (%wt) on the amount of rice straw used in the shrimp farm sludges, and the moisture content (%) in the prepared samples are taken into account to determine the role of rice straw catalytic. Gasification processes were carried out in 60 min in a stainless steel reactor, with a feeding rate of 0.5 kg/h and an air-pumped flow rate of 2 L/min. All experiments were performed under different conditions of working temperatures (600, 700, 800, and 900 °C), sample composition (0, 20, 40, and 60 %wt of rice straw added), and moisture content of the feedstock (20, 40, 60, 80, and 90%). It is essential to confirm that the change in sample moisture content and the working temperature are also significant to the production of hydrogen throughout the process. As the moisture content increase from 20 to 40%, the hydrogen yield is proportionally increased by 5–10%. On the aspect of working temperature influence, the hydrogen composition increased from 11% at 600 °C to 27% at 900 °C for the RS sample, from 13% at 600 °C to 29% at 900 °C for the RS20, from 17% at 600 °C to 35% at 900 °C for the RS40 sample, and from 19% at 600 °C to 43% at 900 °C for the RS60 sample. The findings in this work confirm the rice straw catalyst's role in enhancing hydrogen production via the gasification process. Furthermore, this work provides guidance information for simple but effective processes that can not only deal with the sludge waste management issue but also create a waste-to-energy route suitable for medium and small-scale aquaculture businesses.

VALORIZATION OF ROASTED HAZELNUT CUTICLES SUPPORTED BY LABORATORY TECHNIQUES

this paper reports the experimental results of an on-going project running at lab-scale and aimed at the valorization of roasted hazelnut cuticles through both chemical (i.e., solvent extraction) and thermochemical treatment (i.e., torrefaction) routes. In particular, the potential of using water as a green solvent for the extraction of bioactive compounds (i.e., substances of chemical-food-pharmaceutical interest, such as the polyphenols) contained in residues originated by industrial processing of hazelnuts has been investigated, applying the conventional laboratory Soxhlet extraction procedure. A subsequent valorization stage has been explored for the spent post-extraction residues versus the “as collected” ones; they lend themselves to become “renewable” solid fuels thanks to torrefaction, which is a “mild” thermochemical conversion process. The obtained results are first presented in terms of theoretical yields of the bioactive compounds of interest with respect to the original mass of hazelnut residue; in addition, the findings on torrefaction are discussed in terms of performance indexes with respect to the torrefied fuel and quantitatively expressed as correlations as a function of temperature.