Thermochemical Conversion Processes Research Articles

Pyrolysis of pigeon pea (Cajanus cajan) stalk: Kinetics and thermodynamic analysis of degradation stages via isoconversional and master plot methods

Detailed analysis of thermo-kinetics, reaction mechanism, and estimation of thermodynamic parameters are imperative for the design of reactor systems in thermochemical conversion processes. Present investigation was aimed at exploring the pyrolysis potential of pigeon pea stalk (PPS) by thermogravimetric experiments at 10, 20, and 30 °C/min heating rates. Maximum devolatilization of PPS was found to take place below 480 °C. The average activation energy for PPS pyrolysis was found to be 95.97, 100.74, 96.24, and 96.64 kJ/mol by Kissinger-Akahira-Sunose, Flynn-Wall-Ozawa, Starink, and Friedman method, respectively. Statistical analysis by one way analysis of variance method by employing Tukey test revealed that the difference in activation energy estimated from different methods was insignificant. Thermodynamic parameters (ΔH, ΔS, and ΔG) together with reaction mechanisms were also evaluated. Difference in the activation energy and enthalpy was found to be less than 5 kJ/mol. R2 and R3 models were found best fitted with experimental PPS pyrolysis data.

Valorization of Hemp Stalk Waste Through Thermochemical Conversion for Energy and Electrical Applications

The presented research aimed at finding new ways to value hemp by-products (stalks) from the cannabidiol industry through thermochemical conversion. Chemical and elemental composition of hemp biomass was investigated by successive chemical extractions and Scanning Electron Microscopy along with Energy-dispersive X-ray Spectroscopy. Proximate and elemental analyses completed the chemical characterization of the hemp biomass and its biochar. Thermogravimetric analysis of the hemp biomass allowed to understand its kinetic of decomposition during thermal conversion. The carbon structure and porosity of the biochar were assessed by Raman spectroscopy and CO2 gas adsorption. Properties of interest were the energy production measured through calorific values, and the electrical conductivity. Two ways of valorisation of the hemp biomass were clearly identified, depending mainly on the chosen pyrolysis temperature. Hemp biochar carbonized at 400–600°C were classified as lignocellulosic materials with a good potential for solid biofuel applications. Specifically, the resulting carbonized biochar presented low moisture content (below 2.50%) favourable for high fuel quality, low volatile matter (27.1–10.4%) likely to show lower particle matter emissions, limited ash content (6.8–9.8%) resulting in low risk of fouling issues during the combustion, high carbon content (73.8–86.8%) suggesting strong energy density, associated with high higher heating values (28.45–30.95 MJ kg−1). Hemp biochar carbonized at 800–1000 °C displayed interesting electrical conductivity, opening opportunities for its use in electrical purposes. The electrical conductivity was related to the evolution of the biochar microstructure (development of graphite-like structure and changes in microporosity) in regard with the thermochemical conversion process parameters.Graphical abstract

Crude Glycerol as a Potential Feedstock for Future Energy via Thermochemical Conversion Processes: A Review

Biodiesel is an emerging substitute for petroleum-based products. It is considered an ecologically safe and sustainable fuel. The high cost of biodiesel production is linearly related to its feedstock. Crude glycerol, which is a by-product of the biodiesel industry, is also a major challenge that must be addressed. A large volume of crude glycerol needs to be disposed of, and this involves processing, dumping, and land requirements. This increases the cost of biodiesel production. One way to decrease the cost of biodiesel production is to utilize its by-product to make valuable products. Crude glycerol can be processed to produce a variety of chemicals and products. The present utilization of crude glycerol is not enough to bring down its surplus availability. Thermochemical conversion processes can utilize crude glycerol as a starting feedstock and convert it into solid, liquid, and gaseous fuels. The utilization of crude glycerol through integrated thermochemical conversion processes could lead to an integrated biorefinery. This review paper highlights the research scope for areas where crude glycerol could be utilized as a feedstock or co-feedstock in thermochemical conversion technology. Various thermochemical conversion processes, namely, gasification, pyrolysis, combustion, catalytic steam reforming, liquefaction, and supercritical water reforming, are discussed and shown to be highly suitable for the use of crude glycerol as an economical feedstock. It is found that the integration of crude glycerol with other thermochemical conversion processes for energy production is a promising option to overcome the challenges related to biodiesel production costs. Hence, this paper provides all the necessary information on the present utilization status of crude glycerol in thermochemical conversion processes, as well as identifying possible research gaps that could be filled by future research studies.

Bioleaching of Sorghum Straw in Bioreactors for Biomass Cleaning

Pretreatments are often needed for lignocellulosic biomass feedstocks before either thermochemical or biochemical conversion processes. Our previous research has demonstrated the potential of bioleaching, with its superior capability of removing certain inorganic compounds compared to water leaching, to improve biomass quality for thermochemical conversion in biofuel production. In this study, the bioleaching process was scaled up from 250 mL beakers to be carried out in custom-designed 2.5 L bioreactors. The fungus Aspergillus niger was used in the bioreactors for leaching sorghum straw biomass with an initial ash content of 6.0%. The effects of three operating parameters on leaching efficiency (i.e., residual ash content) were extensively studied, including the fungal mass added to each reactor, leaching time, and glucose concentration in the starting liquid phase. Response surface methodology (RSM) was used for the experiment design. The results showed that the average residual ash content of the sorghum feedstock after bioleaching was significantly lower (3.63 ± 0.19%) than that of the ash content (4.72 ± 0.13%) after water leaching (p < 0.00001). Among the three parameters, glucose concentration in the starting liquid phase had the most significant effect on leaching effectiveness (p = 0.0079). Based on this outcome, subsequent bioleaching experiments yielded reductions in residual ash content to as low as 2.73%.

Friction and wear properties of biomass-derived oils via thermochemical conversion processes

Tribological properties of biomass-derived oils (bio-oils) were experimentally investigated, and the properties were compared with that of standard mineral oils used for lubrication purposes. Bio-oils were obtained from fast pyrolysis (using poultry and pine), gasification (“gasitar” using pine) and hydrothermal liquefaction processes (using Scenedesmus and Nannocholoropsis). The friction and wear tests were conducted using a ball on the disk tribometer test. The results showed that the coefficient of friction (COF) were around 0.02 for both gasitar and Scenedesmus bio-oil; whereas, catalytic and non-catalytic pyrolysis oils had a COF around 0.1. The wear measurements showed that catalytic fast pyrolysis bio-oils had lower wear followed by non-catalytic bio-oil and “gasitar”. Nannocholoropsis bio-oil had the highest amount of wear, and algal bio-oils showed higher wear compared to other oils. The bio-oil chemical analysis indicated that catalytic and non-catalytic fast pyrolysis bio-oil had higher oxygen content, while algal bio-oil had higher nitrogenates. Gasitar had higher hydrocarbon content with lower oxygen and nitrogenates making it a favorable lubricating oil.

Thermodegradation characterization of hardwoods and softwoods in torrefaction and transition zone between torrefaction and pyrolysis

Torrefaction and pyrolysis are two common thermochemical conversion processes to convert biomass into biofuel. This study aims to treat woody biomass within the temperature range of torrefaction and transition zone at 210–390 °C. The weight loss of the hardwoods (up to 64 wt%) and softwoods (up to 60 wt%) exhibit a drastic change at temperatures of 240–300 °C and 240–330 °C, respectively. The biomass shrinkage ratio (about 15–22%) along the tangential and radial directions is more pronounced than that along the longitudinal direction. The H/C and O/C ratios decrease as the temperature increases to 300 °C. Thermogravimetric analysis shows that the treated hardwoods and softwoods exhibit drastic changes at temperatures of 270–300 °C and 300–330 °C, respectively. Fourier-transform infrared spectroscopy analysis shows that cellulose constituent in hardwoods is easier to degrade than that of softwoods. The transition zone is not a suitable operation for treating wood due to its low solid yield.

CFD modelling of coal gasification in a fluidized bed with the effects of calcination under different operating conditions

This paper investigates the thermochemical and physical conversion processes of coal gasification numerically with particular interest on calcination in a bubbling fluidized bed furnace. A comprehensive Eulerian-Eulerian three-dimensional model is developed for studying the gasification process. Three calcination cases are carried out under different operating conditions while one inert case is conducted to evaluate the effect of calcination. The presented numerical results aim at determining the mechanism of coal gasification in an air-steam environment with different flowrates. Evidence of particle segregation is found in the bed of coal and limestone due to density reduction and diameter shrinkage. Char conversion is investigated for different air-coal and steam-coal ratios, also the effect of bed temperature, fluid flowrate and fuel feeding rate on the carbon conversion is studied comprehensively. The highest char conversion rate is observed in the airflow rate of 17.0 kg/h where the bed temperature is found to be maximum. A noticeable impact of calcination is found in the gaseous emission while increasing CO2 concentration. Time averaged solid and gas temperature and species concentration profiles indicate the steady-state condition of numerical simulation.

Nitrogen Gas Adsorption Filter (NgAF) to enhance producer gas quality

Biomass gasification is a thermochemical conversion process of solid biomass into a gaseous fuel called producer gas that can be used to generate power and electricity. The producer gas consists of around 47% of Nitrogen (N2), 24% Carbon Monoxide (CO), 16% Carbon Dioxide (CO2), 12% Hydrogen (H2), and 1% Methane (CH4). However, Nitrogen (N2) content in the producer gas reduces its heating values as N2 acts as a diluent because of the low calorific value (LCV) of gas. This study aims to design a Nitrogen gas filter for capturing nitrogen gas from producer gas to increase the heating value of producer gas as fuel in combustion. The method to increase the heating value of producer gas will increase the number of combustible gases or reduce the composition of non-combustible gases in producer gas. The use of material name zeolite with its microporous structures able to adsorb nitrogen molecules and act as catalysts to chemical reactions. Zeolites 5A have a small pore highly efficient to adsorb nitrogen gas because pore diameter is relatively similar to the size of nitrogen molecules. The quality of the producer gas depends on the design and operating parameters of the zeolite catalyst. Nitrogen Gas Adsorption Filter is a new method that has to be designed to improve the previous producer gas quality. Nitrogen Gas Adsorption Filter consists of a cylindrical shape body packed with crushed zeolites 5A. When this method of adsorption process is applied, the heating value of the producer gas is increased by observing the quantity of blue flame colour produced by NgAF.

Recent progress and perspectives of catalyst design and downstream integration in biomass tar reforming

In the last few decades, the development of biomass energy has become a key research focus to press the emissions of greenhouse gas. Syngas production from biomass tar reforming in the presence of the heterogeneous catalyst has been proved to be a clean and promising technology, which could be further connected to the downstream for fuel valorization. Up to now, some literatures has screened the reaction pressure, temperature, atmosphere, and heterogeneous catalyst in tar elimination during the biomass thermochemical conversion process. However, there are some problems, like the economical catalyst chosen for the industrial development of gasification, and integration difficulties between gasification and downstream technologies are still not well discussed. Hence, in this review, we first assess the recent advancements in catalyst fabrication and the activity performance in reforming biomass tar and tar model compounds. After that, the clean-up of produced gas for the next-step application is reviewed. Importantly, we discuss the composition of the produced gas, the possibilities and challenges of the integration with the production of methane, methanol, ethanol, and C2+ alcohols. Finally, the conclusion and prospective are concluded to give an outlook for the development of catalyst, biomass tar reforming, and integration with downstream technologies.

Robustness enhancement of biomass steam gasification thermodynamic models for biohydrogen production: Introducing new correction factors

Biomass steam gasification is the most effective thermochemical conversion route for producing enriched biohydrogen from various biowaste feedstocks. Such processes are designed by solving constrained model equations and applying these to estimate the product composition against various feedstocks. In this paper, robust methods for optimizing the biomass steam gasification process to produce H2 are presented. Thermodynamic models were developed and optimized to determine new competitive correction factors based on experimental data obtained from previous studies to correct the errors associated with these models. The newly introduced correction factors were applied to the equilibrium constants and Gibbs free energy equations of the thermodynamic models. The proposed corrected models were validated and compared with existing modeling and experimental studies. The H2 production from rice husks was in good agreement with the experimental composition. The overall root-mean-square errors of the stoichiometric and non-stoichiometric thermodynamic models decreased from 2.89 to 2.36 and from 4.53 to 2.46, respectively. Finally, the proposed models were applied to wood biomass and subjected to parametric analysis by varying the operating parameters, including temperature, moisture content, and steam to biomass ratio. This study will help to address the issues related to biohydrogen production from thermochemical conversion processes using different biomass feedstocks.

Thermal Analysis Technologies for Biomass Feedstocks: A State-of-the-Art Review

An effective analytical technique for biomass characterisation is inevitable for biomass utilisation in energy production. To improve biomass processing, various thermal conversion methods such as torrefaction, pyrolysis, combustion, hydrothermal liquefaction, and gasification have been widely used to improve biomass processing. Thermogravimetric analysers (TG) and gas chromatography (GC) are among the most fundamental analytical techniques utilised in biomass thermal analysis. Thus, GC and TG, in combination with MS, FTIR, or two-dimensional analysis, were used to examine the key parameters of biomass feedstock and increase the productivity of energy crops. We can also determine the optimal ratio for combining two separate biomass or coals during co-pyrolysis and co-gasification to achieve the best synergetic relationship. This review discusses thermochemical conversion processes such as torrefaction, combustion, hydrothermal liquefaction, pyrolysis, and gasification. Then, the thermochemical conversion of biomass using TG and GC is discussed in detail. The usual emphasis on the various applications of biomass or bacteria is also discussed in the comparison of the TG and GC. Finally, this study investigates the application of technologies for analysing the composition and developed gas from the thermochemical processing of biomass feedstocks.

Simulation studies on the co-production of syngas and activated carbon from waste tyre gasification using different reactor configurations

• Waste tyre gasification was evaluated in three different reactor configurations. • Fluidized bed, fixed bed and rotary kiln reactors were evaluated. • Fixed bed reactor was the most suitable reactor configuration for syngas production. • Fluidized bed reactor was the most suitable for activated carbon production. • Coproduction of syngas and activated carbon was most suitable in fluidized reactor. Gasification is one of the most efficient thermo-chemical conversion processes for transforming waste tyres into syngas and high-valued solid carbon products such as activated carbon (AC). This study evaluated the co-production of syngas and AC in three reactor configurations: fluidized bed, fixed bed, and rotary kiln at the systems level. A single-stage steam gasification and char activation process was simulated using Aspen Plus V10 software. The effects of gasification parameters such as equivalence ratio (ER) and steam-to-fuel ratio (SFR) were investigated and compared. The best conditions for the co-production of syngas and AC in the reactors were evaluated and compared. Brunauer-Emmett-Teller (BET) computational analysis was used to predict the surface area of the AC. The fluidized bed gasifier has the potential to produce syngas with a low heating value (LHV) of 6.67 MJ/Nm 3 , cold gas efficiency (CGE) of 82.4% LHV , AC with BET surface area of 698.63 m 2 /g and a carbon conversion ratio (CCR) of 92.5%, the fixed bed gasifier has a syngas LHV of 6.25 MJ/Nm 3 , CGE of 85.9% LHV , AC with BET surface area of 432.51 m 2 /g and CCR of 97.3% and the rotary kiln gasifier has a syngas LHV of 5.96 MJ/Nm 3 , CGE of 74% LHV , AC with BET surface area of 661.73 m 2 /g and CCR of 93%.

Sorption and recovery of phenolic compounds from aqueous phase of sewage sludge hydrothermal liquefaction using bio-char

Bio-char, a by-product of thermochemical conversion processes, has a great potential in phenolic compounds sorption from the waste aqueous phase produced from the hydrothermal liquefaction (HTL) process while being a low-cost sorbent. This study investigated the effect of temperature, pH, bio-char concentration, and mixing speed on two types of bio-char sorption of phenolic compounds using Taguchi's design of experiment and response surface method. Isothermal kinetics and thermodynamic properties were also evaluated to explain the sorption mechanism. The experimental results were well described by the pseudo-second-order kinetic model for both types of bio-char. The Langmuir isotherm model was found to be more suitable at high sorption temperatures, while the Freundlich isotherm model was better at low temperatures. Finally, the alkaline desorption and regeneration experiments were examined, and the eluents with phenolic compounds were characterized using a liquid chromatography-mass spectrometer.

Energy recovery from wood pellets and waste mulching film with minimization of harmful byproducts via thermochemical conversion with CO2 agent

The additive and kind of thermochemical agent can greatly affect the thermochemical conversion process. In this study, the influences of Waste mulching film (WMF) as the additive and CO2 as the thermochemical agent on the characteristics of thermochemical products of Wood pellets (WP) were studied. With increasing temperature, the total non-condensable gas yields in N2 and CO2 atmospheres increased. The thermochemical conversion of WP in CO2 led to a higher total non-condensable gas yield than the conversion in N2 because the thermal cracking of volatile species was promoted in the former case. Above 700 °C in the CO2 environment, the dehydrogenation of volatiles and hydrogenation of the CO2 agent greatly increased the CO and CH4 yields. In addition, the yields of polycyclic aromatic compounds, phenolic compounds, and benzene derivatives obtained in CO2 were lower than those obtained in N2 at all tested temperatures. The CO2 agent significantly decreased the yield of WP-derived char at > 700 °C; this was likely because it expedites the evolution of volatile species from WP during thermochemical conversion. The addition of WMF to the thermochemical conversion of WP decreased the CO and CO2 yields by lowering the oxygen content of the feedstock, the CH4 yield by suppressing the methanation reaction in the CO2 environment, and the yields of harmful aromatic compounds by lowering the overall lignin content of the feedstock; by contrast, the addition increased the yield of fuel-range hydrocarbons. The higher content of volatile matter in WMF compared with that of WP decreased the char yield compared with the case in which the thermochemical conversion of WP was performed without the additive.

Hydrochar: A Review on Its Production Technologies and Applications

Recently, due to the escalating usage of non-renewable fossil fuels such as coal, natural gas and petroleum coke in electricity and power generation, and associated issues with pollution and global warming, more attention is being paid to finding alternative renewable fuel sources. Thermochemical and hydrothermal conversion processes have been used to produce biochar and hydrochar, respectively, from waste renewable biomass. Char produced from the thermochemical and hydrothermal decomposition of biomass is considered an environmentally friendly replacement for solid hydrocarbon materials such as coal and petroleum coke. Unlike thermochemically derived biochar, hydrochar has received little attention due to the lack of literature on its production technologies, physicochemical characterization, and applications. This review paper aims to fulfill these objectives and fill the knowledge gaps in the literature relating to hydrochar. Therefore, this review discusses the most recent studies on hydrochar characteristics, reaction mechanisms for char production technology such as hydrothermal carbonization, as well as hydrochar activation and functionalization. In addition, the applications of hydrochar, mainly in the fields of agriculture, pollutant adsorption, catalyst support, bioenergy, carbon sequestration, and electrochemistry are reviewed. With advancements in hydrothermal technologies and other environmentally friendly conversion technologies, hydrochar appears to be an appealing bioresource for a wide variety of energy, environmental, industrial, and commercial applications.

Upcycling Postconsumer High-Density Polyethylene (PC-HDPE): Thermal Stability and Kinetics Study of the Filaments Extruded from PC-HDPE

Thermal stability and kinetics of thermolysis of postconsumer milk containers made of high-density polyethylene (PC-HDPE) and filament rods extruded from them (HDPE-F) were examined by thermogravimetric analysis (TGA) with six linear temperature programs under a stream of nitrogen. The total weightloss of each sample took place in a one-step decomposition to volatiles at the heating rates, β = 1, 10, 25, 50, 70, and 100 Kmin-1. The values of initial decomposition temperature, the temperature at the maximum thermal degradation rate, and the maximum rate of decomposition were increased by increasing the heating rate as was the expectation. The isoconversional method was used to evaluate the fundamental kinetic parameters, the activation energy barrier (Ea ), the Arrhenius pre-exponential factor (A), and the mechanism of the reaction, f(α). The values of Ea were independent of the model and heating rate, as was expected. However, the values of A depended on the model and the extent of reaction (α). The values of the Ea of PC-HDPE initiated at 171 kJ/mol at α = 0.05 and it increased to 207 kJ/mole at α = 0.95. The values of Ea of the HDPE-F rod were relatively constant for all α values, being 227 ± 3 kJ/mol. It was justified by the absence of easily volatilized substances in the HDPE-F. Knowledge of the thermal stability and decomposition kinetics of the starting materials (PC-HDPE) and the product (HDPE-F) is important in the context of thermochemical conversion processes aimed at the use of PC-HDPE as raw materials for recycling, upcycling, and down-cycling for objects used under room conditions.

Thermogravimetric and kinetic analysis of biomass and polyurethane foam mixtures Co-Pyrolysis

Alternative fuels are crucial for the decarbonisation of high-energy demanding processes. The utilisation of waste materials to produce alternative fuels is especially interesting since, the co-pyrolysis of waste plastics and biomass was lately introduced as promising method since the synergistic effect might enhance the product properties compared to those from individual pyrolysis. Furthermore, the utilisation of waste biomass, like sawdust, is interesting since it does not influence the sustainability of biomass consumption, and even more, it avoids the usage of raw feedstock. Thermogravimetric analysis is performed to determine the thermal degradation behaviour and kinetic parameters of investigated mixtures to find the most appropriate utilisation method. Co-pyrolysis was conducted for three mixtures with the following biomass/polyurethane ratios: 75-25%, 50-50%, 25–75%, over a temperature range of 30–800 °C, at three heating rates 5, 10 and 20 °C/min, under an inert atmosphere. Obtained results were subjected to comprehensive kinetic analysis to determine effective activation energy using the isoconversional model-free methods and provide a detailed analysis of the samples' thermal degradation process. This work aimed to identify the main thermal decomposition stages during co-pyrolysis of biomass and polyurethane mixtures and provide the mixture composition's influence on the considered thermochemical conversion process.

Thermo-chemical conversion of cannabis biomass and extraction by pressurized liquid extraction for the isolation of cannabidiol

Cannabis plants produce acidic cannabinoids, however the neutral form is required to effectively bind to the human cannabinoid receptor. This research aimed to develop and validate methodology for thermo-chemical conversion of acidic cannabinoids during pressurized liquid extraction for the isolation of cannabidiol.Cannabinoid decarboxylation is typically performed by heating plant material or extract, however cannabinoids are thermolabile and can readily degrade or convert to undesired metabolites. Consequently, decarboxylation during the extraction process would minimize additional steps and potential for degradation and metabolite formation thereby proving beneficial in the isolation of neutral cannabinoids.A thermo-chemical conversion process was established to convert acidic cannabinoids to their neutral forms. Subsequent extraction with ethanol yielded a cannabidiol extract of 75.8 % purity. Purification with flash chromatography resulted in cannabidiol rich fractions being collected for liquid-liquid extraction and crystallization. The end product was 91.8 % pure. The loss over the extraction and purification process was analyzed and found to be 22 %, which can be reduced by reprocessing select fractions.The optimized pressurized liquid extraction method using water for thermo-chemical conversion of acidic cannabinoids prior to an ethanol extraction step is proposed. The extraction process combined with purification by flash chromatography and liquid-liquid extraction yields cannabidiol crystals of greater than 90 % purity.

Energy Recovery of Shrub Species as a Path to Reduce the Risk of Occurrence of Rural Fires: A Case Study in Serra da Estrela Natural Park (Portugal)

The accumulation of biomass fuels resulting from the growth of heliophilous shrubs and small tree species at the edge of forests and on scrub and pasture lands contributes to the increased risk of rural fires in Mediterranean climate regions. This situation has been managed with a set of legislative measures launched with the objective of promoting cleaning and the control of these species. Areas of scrub and pasture already constitute the largest part of the annually burnt area in Portugal, resulting in high-intensity fires. In the present study, shrubs and small tree species were characterized in the laboratory. Thermogravimetric, chemical and calorimetric analyses for the evaluation of the potential for the energy recovery of the selected species were carried out. It was observed that energetic valorization (i.e., to enhance the value by planned actions) of these species is difficult because they present high levels of ash and metals, becoming prone to the occurrence of fouling and slagging phenomena. Thus, the creation of value chains that justify the incorporation of these materials becomes very difficult, except if used in non-certified, small-scale and locally based processes. The possibility of recovery through thermochemical conversion processes, such as torrefaction, pyrolysis or gasification, must be studied so that more efficient and feasible recovery alternatives can be found, allowing for the creation of value chains for these residual materials to promote their sustainable management and, thus, mitigate the risk of rural fires occurring.

Thermokinetic study of macadamia carpel pyrolysis using thermogravimetric analysis

AbstractThe macadamia productive process generates a large amount of waste, such as walnut carpel, that is improperly disposed of in most instances. This residue is a promising feedstock for biofuel production and it can be converted through thermochemical routes. Liquid pyrolysis products obtained contain a bio‐oil with great potential for the production of fuels and fine chemicals. The goal of this study was to characterize the macadamia carpel for the first time by ultimate, proximate, FTIR, and TG analysis, as well as HHV determination, which showed this is a potential candidate for thermochemical conversion processes. Thermodynamic and kinetic pyrolysis behaviours were evaluated using Ozawa, Kissinger, Starink, and KAS isoconversional models (140.12, 137.69, 137.41, and 146.63 kJ mol−1, respectively), which attested to the product favourability and the operational viability. Additionally, the master plot method was applied to complete the kinetic description, which identified diffusion and nucleation mechanisms during the carpel degradation. After 50% conversion, the third‐order reaction mechanism occurred due to a predominant lignin decomposition. The results showed that the macadamia carpel properties are similar to traditional feedstock, that it may be decomposed into bio‐oil, and that it can be used as an alternative energy source or bio‐chemicals precursor.