Char Porosity Research Articles

Effect of high-pressure pyrolysis on syngas and char structure of petroleum coke

Petroleum coke, a byproduct of petroleum refining, is considered a potential alternative fuel owing to its low ash content and high calorific value. This study aims to enhance our understanding of the pyrolysis process and its potential applications by investigating the effect of pressure on the pyrolysis of petroleum coke, focusing on changes in its syngas composition and char structure. High-pressure pyrolysis was employed to explore structural changes, decomposition pathways, and gas production. High pressures increase the residence time and promote secondary pyrolysis, leading to the increased production of hydrogen. Also, high pressure can promote gasification reactions such as methanation. The influence of pressure on the chemical and physical structures of the produced char was also observed. Higher pressures resulted in more active secondary pyrolysis, causing a decrease in the aromatic groups and an increase in the aliphatic and oxygen-containing groups in the char. The surface area and porosity of char increased at higher pressures, enhancing its reactivity and gasification rate. Overall, this study provides valuable insights into the effects of pressure on petroleum coke pyrolysis, shedding light on its potential as an alternative energy resource and highlighting changes in gas composition and char structure under various pressure conditions.

In-situ plasma assisted lithium-ion battery cathodes to catalytically pyrolyze lignin for H2-rich syngas production

In-situ plasma assisted lithium-ion battery cathodes catalysis was investigated to pyrolyze lignin to H2-rich syngas, oil and char. The effects of temperature, cathode to lignin ratio and plasma current on syngas production were investigated by using the typical ternary cathode NCM111 (LiNi1/3Co1/3Mn1/3O2) as catalyst and adopting dielectric barrier discharge mode. Response surface methodology based on BOX-BEHNKEN design was used to analyze the significance and interactions of process factors on the syngas yield. The conditions of 837℃, 10.4 %, and 185 mA for obtaining high-yield syngas (22.58 %) were more stringent; thereinto, from high to low, the intensity of factors on the yield was temperature, plasma current, and cathode ratio. Furthermore, different cathodes (non-cathode, NCM811 (LiNi4/5Co1/10Mn1/10O2), LCO (LiCoO2), and LMO (LiMn2O4)) were applied to decouple the catalytic effects of three metals in the NCM111. NCM111 enhanced both lignin gasification and carbonization by reducing condensable components, and NCM811 further improved gasification, but LCO and LMO had weaker gasification ability. NCM111 increased H2 volume fraction from 22.35 % to 67.31 %, NCM811 elevated the micro-discharge performance, promoting the hydrogasification reactions between energetic H species and char to produce more CH4, while LCO and LMO tended to produce the CO-rich syngas. Besides, in-situ plasma and its synergy with cathodes inhibited the formation of heavy aromatics and produced some high-value bio-oils rich in light aromatics, in which NCM111 achieved 92.30 % selectivity towards MAHs. High Ni ratio was beneficial for improving the char porosity, and the chars obtained by using NCM811 had a surface area of 409.29 m2/g, and a pore volume of 0.401 cm3/g. Comparably, the degree of catalytic lignin gasification for preparing H2-rich syngas could be ranked as Ni > Co > Mn in the ternary cathode.

Effect of Bone Char Application on Soil Quality, Soil Enzyme and in Enhancing Crop Yield in Agriculture: A Review

Soil quality, in contrast to air or water, exhibits a heightened level of heterogeneity and necessitates closer examination due to its impact on the well-being of flora, fauna, and human beings. Organic carbon is considered a fundamental indicator of soil quality, as it plays a significant role in strategies aimed at mitigating climate change. The generation of bone char arises from a thermochemical conversion process involving defatted bones. Specific attention is focused on the solubility of P compounds, which serves to classify bone chars as potential slow-release P fertilizers. The introduction of P into the soil can be enhanced through an "internal activation" process facilitated by the adsorption of reduced S compounds. Additional properties of agronomic significance originate from the porosity of bone char, which promotes water retention and provides a habitat function for soil microorganisms. The evaluation of soil quality has been a longstanding practice, involving an examination of physical and chemical characteristics such as pH, nitrogen levels, soil organic carbon, bulk density, accessible water, aggregate stability, particle size distribution, and soil structure. Recently, the concept of soil quality has been expanded to encompass the notion of soil health, which is perceived as a finite, non-renewable resource that undergoes constant change. Research also demonstrates the crucial role of soil biota in the assessment of soil quality, as they exhibit rapid responsiveness to disturbances. Animal bones undergo a process of defatting, degelatinization, and subsequent incineration at temperatures ranging from 600-800°C to produce bone char (BC). Reports indicate that typical BC contains 152 g P kg<sup>-1</sup>, 280 g Ca kg<sup>-1</sup>, and 6.5 g Mg kg<sup>-1</sup>, with carbon content typically falling below 100 g kg<sup>-1</sup>. The solubility of bone char in the soil depends on factors such as pH and the soil's capacity to absorb P, situating it within the range between rock phosphate and triple super phosphate (TSP). The application of bone char to the soil can enhance soil health, resulting in increased crop yield and improved quality.

Advantages of dual CO2 & O2 adsorption model for assessment of micropore development in biochar during two-stage gasification

Residual biochar has the potential to replace commercial carbons even in highly specialised applications, presuming further advances in the engineered biochar production. Optimising biomass conversion requires dynamic feedback on the resultant char porosity, but investigation of pore size distribution (PSD) in pyrogenic carbons is challenging due to their extremely ultramicroporous nature. The most common probe molecule used in gas adsorption methods, N2, is often unable to access the narrowest pores, while CO2 can analyse only pores <10 Å.We propose an approachable way to evaluate PSD of ultramicroporous carbons by simultaneously fitting the 2D-NLDFT (two-dimensional non-local density functional theory) kernels to the CO2 and O2 isotherms. Using O2 as the probe molecule allowed collecting isotherms for the ultramicroporous pyrolytic char, for which a negligible adsorption of N2 was observed. For the more activated, gasification chars, reaching equilibrium for N2 adsorption took up to 8 h for some datapoints. O2 adsorption was much faster, resulting in the total runtime more than two times shorter than for the N2 tests.By analysing chars from the semi-pilot scale gasifier, we confirmed the dependence of the char structure on the process parameters, but we also suspect a strong influence of the reactor design.

High temperature viscoelastic behaviour of sugarcane bagasse char and coal blends: Role of oxygen and porosity of char on fluidity reduction

This paper focuses on the introduction of sugarcane bagasse, an agricultural byproduct, as a renewable carbon-based additive to metallurgical coal to produce biocoke for the steel industry. Through subjecting pelletized sugarcane bagasse samples to various pyrolysis conditions, chars with varying properties were generated. With increasing final pyrolysis temperature (200, 400, 600, and 800 °C), a rise in carbon content and decline in oxygen, nitrogen and hydrogen levels in the chars were observed. The presence of an inert purge gas during pyrolysis prompted abundant micropore formation between 400 and 600 °C, yielding high specific surface area (SSA > 300 m2/g) chars at 600 °C and 800 °C. Conversely, chars produced in a fixed (unpurged) nitrogen environment exhibited minimal porosity and consequently low SSAs (<5m2/g). These various chars were then blended (at 10 % addition) with a medium-volatile bituminous coal to evaluate their impact on the viscoelastic properties of the coal. Chars pyrolyzed to lower final temperatures had the greatest detrimental effect on blend fluidity due to (1) their continued devolatilization which introduced void spaces in the blend creating pathways for the exhaust of coal volatiles, and (2) their elevated oxygen content, which scavenged essential mobile hydrogen needed to facilitate viscoelastic behaviour. Furthermore, chars with similar oxygen content but substantially different (by over two orders of magnitude) SSAs generated comparable coal-char blend viscosity profiles, indicating that the presence or absence of micropores in an additive does not significantly influence the viscoelastic behaviour of the coal. The reduction in blend fluidity for the addition of chars pyrolyzed to 800 °C was comparable to the modelled addition of inertinite macerals, implying that these high-temperature chars predominantly serve as inert solid additives. Comparison to a blend with 10 % mesoporous activated charcoal as the additive confirmed that it is mesopores that destroy fluidity, while micropores do not play a significant role. Mesopores were identified to adsorb/trap the relatively large tar-like compounds that are responsible for coal plasticity. Collectively, this research identifies three key factors contributing to fluidity reduction in coal-additive blends: void creation, oxygen content, and mesoporosity. These findings offer insights into optimizing biocoke production processes.

A percolation model of fly ash formation during the combustion of non-uniform porous char

An improved percolation model has been introduced to predict the particle size distributions (PSDs) of produced residue during pulverized coal char combustion. A three-dimensional cluster of interconnected sites representing a single char particle is constructed at a given size. These sites are classified into surrounding gas, macropores, carbon, or ash. Non-uniform porous char structures and the melting performances of the ash particle have been considered to approach the most realistic scenario. The char fragmentation and ash coalescence process is simulated by checking the connectivity and proximity of occupied sites. The effects of char particle sizes are addressed by using char PSD data as the input to the model. The numerical results were compared with the measured PSDs of fly ash and show a good agreement. The effects of porous char structure and included minerals on the sizes of produced particles during combustion are further investigated. The simulation results indicate that the mean sizes of produced particles initially decrease (N<0.7) and then increase with char consumption. The char fragmentation behavior dominates in the preliminary and middle stages of char burning, while the ash coalescence is the primary behavior in the char burnout stage. The mean sizes of produced particles increase with the lower char porosity and the higher extent of pore aggregation. The size difference between PM20 and PM20+ increases when the macropores are repositioned to be aggregated. The mean sizes are positively related to the ash content and ash coalescence parameter in the middle and late stages of char burning.

Dynamic biomass char porosity during gasification: Model compared with data

This investigation presents a new biomass char porosity model as a function of char conversion during gasification and compares it with entrained-flow data from poplar, corn stover and switchgrass particles reacting with H2O, CO2, and combinations of both at temperatures of 1050–1350 °C. The experimental data include particle temperature, mass, size, and shape combined with porosity, BET surface area, geometric specific surface area and SEM images of char vascular structure. The new theoretical model describes char porosity changes during char conversion and the model indicates that porosity increases monotonically, consistent with the data. The vascular char structure remains intact even at the highest conversions and this structure effectively transports reactants and products through the particle, with reactions occurring on the walls of these vascular vessels, referred to here as vascules. The investigation shows that char porosity most strongly depends on average vascule diameter which, in turn, increases with increasing conversion. This investigation extends current understanding of the mechanism of heterogeneous biomass char reactions (gasification and oxidation) under kinetically controlled conditions. This work concludes that (1) kinetically controlled biomass gasification involves reactions on the walls of vascules with small contributions from the nanopores or even mesopores; (2) char porosity increases monotonically with increasing char conversion in the kinetically and internal transport-controlled regimes; and (3) observed porosity behaviors correspond the predicted behaviors.

Biomass char gasification kinetic rates compared to data, including ash effects

This investigation provides both experimental and theoretical analyses of biomass char gasification kinetics over 1150–1350 °C in the environment of CO2, H2O and combinations of these reactants. The experimental data include continuous measurements of particle mass, external and internal temperatures, shape, and size with periodic but not continuous measurements of char porosity, pore size distribution, and pore surface area. The model describes heterogeneous char gasification for poplar wood, corn stover and switchgrass in different shapes and industrially relevant sizes (12.5 mm and smaller). Nonlinear least-squares regression produces optimized power-law model parameters for global kinetics that describe biomass char gasification with respect to both CO2 and H2O separately and in combination. A single set of kinetic parameters describes reaction rates for all three fuels. Model simulations agree with measured data at all stages of char conversion even though the observed mass loss rates change significantly with conversion. The change in rate with conversion depends strongly on ash content, and this investigation provides a simple and theoretically based reaction rate expression that includes the effect of inert ash occupying an increasing portion of the reactive surface with increased conversion.

Revalorizing a Pyrolytic Char Residue from Post-Consumer Plastics into Activated Carbon for the Adsorption of Lead in Water

This work focuses on the use of a char produced during the pyrolysis of a mixture of non-recyclable plastics as a precursor for the preparation of porous activated carbon with high developed adsorption uptake of lead in water. Physical and chemical activation was used to enhance the porosity, surface area, and surface chemistry of char. The final activated carbon materials were deeply characterized through N2 adsorption isotherms, scanning electron microscopy, Fourier transformed infrared spectroscopy, analysis of the metal content by inductively coupled plasma mass spectroscopy, and pH of point zero charge. The native char displayed a Pb adsorption uptake of 348 mg Pb·g−1 and considerably high leaching of carbon, mainly organic, ca. 12%. After stabilization with HCl washing and activation with basic character activators, i.e., CO2, NaOH, and KOH, more stable adsorbents were obtained, with no organic leaching and a porous developed structure, the order of activation effectiveness being KOH (487 m2·g−1) &gt; NaOH (247 m2·g−1) &gt; CO2 (68 m2·g−1). The activation with KOH resulted in the most effective removal of Pb in water with a saturation adsorption uptake of 747 mg Pb·g−1.

Density functional theory and experimental study on the chemisorption and catalytic decomposition of benzene over exposed bio-char surface: The influence of unsaturated carbon atoms and potassium

Catalytic decomposition over char surface is an effective approach for tar removal. In this work, the density functional theory (DFT) and experiments were used to study the complicated mechanism of the interaction between specific sites on char surface and tar compound at molecular level. Two kinds of bio-char models were used and compared. Three molecular reaction paths were built and corresponding species were optimized. The characteristics of electron density of key components and reaction potential energy were calculated and analyzed. Results show that heterogeneous adsorption of benzene on the active sites of char surface could effectively enhance the decomposition of benzene due to the electron shift caused by chemisorption on char surface. The decomposition temperature is largely reduced from 1100℃ to 900℃ or lower. The band gaps indicate that benzene tends to be more likely excited by model char without potassium, which has more dangling bond on char surface. Potential energy results of three reaction paths show that activation energies of about 208.64 kJ/mole and 163.32 kJ/mole are needed for ring breakage of benzene in Path-1 and Path-2, which are much lower than that of thermal decomposition. The energy barrier for benzene decomposition over char-K is 270.04 kJ/mole. Potassium plays a negative effect on the cracking of tar due to the pore polycondensation and occupation of active sites. Kinetic analysis reveals that the char-tar interactions are largely affected by temperature and higher temperature benefits the breakage of aromatic ring. Experimental results indicate that improving the porosity and surface area of char, especially the active surface area with unsaturated carbon atoms, is crucial for the activation and decomposition of aromatic tar compounds.

Pore development during CO2 and H2O activation associated with the catalytic role of inherent inorganics in sewage sludge char and its performance during the reforming of volatiles

We present a highly-detailed discussion on the pore development in sewage sludge char to better understand its transformation and subsequent role in volatiles reforming. Interactions with the pyrolytic gas can change the porosity of biochar that subsequently participates in the volatiles reforming, thus affecting the product yield and quality. The results demonstrated that H2O activation was more susceptible to the catalytic effects of inorganics, pointing out the more selective nature of CO2. Interestingly, we found important difference between ultra- and supermicropores role in the CO2 activation and toluene conversion. Thus, we suggest distinguishing the micropore types in char porosity assessment.

Determination of size and porosity of chars during combustion of biomass particles

This research focused on the size and overall porosity (pore volume) of carbonaceous chars, originating from high-heating rates and high-temperature pyrolysis and/or combustion of biomass. Emphasis was given to torrefied biomass chars. First, the porosity of char residues of single biomass particles of known mass was determined, based on an assumed value of skeletal density and by comparing experimentally observed temperature-time histories with numerical predictions of their burnout times. The average char porosities (effective porosities) of several raw and torrefied biomass particles were calculated to be in the range of 92–95%. Thereafter, these deduced porosity values were input again to the model to calculate the size of chars of other biomass particle precursors, whose initial size and mass were not known. Such biomass particles were sieve-classified to different nominal size ranges. This time, besides the porosity, representative time-temperature profiles of biomass particles in the aforementioned size ranges were also input to the model. Biomass particles are highly irregular with large aspect ratios and, in many cases, they melt and spherodize under high heating rates and elevated temperatures. Knowledge of the initial size of the chars, upon extinction of the volatile flames, is needed for modeling their heterogeneous combustion phase. For this purpose, numerical predictions were in general agreement with measurements of char size obtained from both scanning electron microscopy of captured chars and real-time high-speed, high-magnification cinematographic observations of their combustion. Results showed that the generated chars of the examined biomass types were highly porous with large cavities. The average initial dimension of the chars, upon rapid pyrolysis, was in the range of 50–60% the mid-value of the mesh size of the sieves used to size-classify their highly irregular parent biomass particles.

Permeability variations of lignite and bituminous coals under elevated pyrolysis temperatures (35–600 °C): An experimental study

Studies on permeability under pyrolysis temperatures (PTs) can provide instructions for syngas production of underground coal gasification (UCG). Permeability variations of lignite, high volatile bituminous coal (HVBC) and medium volatile bituminous coal (MVBC) under elevated PTs (35°C–600 °C) were studied. Structure and weightlessness as well as maturity of coal detected by methods of micro structure observation, nuclear magnetic resonance, thermogravimetric analysis, and liquid yield measurement, were investigated and clarified to probe the factors influencing permeability variation. The results showed: (1) permeability of lignite and HVBC as well as MVBC increased during 35–200 °C. Lignite permeability decreased during 200–600 °C while HVBC and MVBC permeability decreased during 200–400 °C and then increased during 400–600 °C; (2) for coals with different maturities, pyrolysis reactive strength controlled the permeability. Lignite permeability were always the greatest followed by HVBC, and MVBC permeability were always the lowest, at PTs of 125–500 °C; (3) for an individual coal, permeability variation was controlled by the relative strength between positive factors (water and volatiles’ discharge, stable char framework, increased inertoid content, and high porosity of char) and negative factors (blocking of penetration channels by tars or char fines or a mix of these two, closure of macro-pores and fractures, and unstable char framework).

The Influence of Pore Distribution of Coal Char in the Char Fragmentation and Included Minerals Partitioning: A Percolation Modeling

The processes of char fragmentation, including mineral partitioning and particulate matter (PM) formation during dense and porous char combustion, were observed by a site percolation model. This model simulated the diffusion-controlled regime of char combustion, and the size distributions of included minerals in typical bituminous coal were determined by the computer-controlled scanning electron microscope (CCSEM), and the data were put into the char matrix randomly. The model presents the influence of initial pore distribution on char oxidation and fragmentation, the impact of the char conversion process on the extent of fragmentation, the change of ash distributions with the char conversion, and the particulate matters (PM) size distribution, which is derived from the consequence of the competition between char fragmentation and included minerals partitioning and coalescence. The results indicate that with increasing initial char porosity (φ), the number of large size pores increases but the number of pores decreases, which leads to open pores increasing, close pores decreasing, and the surface reaction area increasing. While φ ≥ 0.4, char fragmentation obviously occurs during the stage in which the rates of char conversion are 0.4–0.6, and it looks as though the maximum value of fragmentation will transfer to an earlier conversion stage if it has a larger φ. The enhanced φ shows a positive effect on the increase in the number and concentration of PM &lt; 10 μm (nominally aerodynamic diameter), this is attributed to char fragments more drastically, and the probability of mineral coalescence reduces a lot.

Porous coal char-based catalyst from coal gangue and lignite with high metal contents in the catalytic cracking of biomass tar

In this study, coal gangue and lignite with high metals-containing are used to prepare porous coal char-based catalysts for biomass tar decomposition via a simple pyrolysis method under CO2 atmosphere. The CO2 etching during the preparation process of the catalysts helps to improve the porosity of the coal char, and the metals in coal are exposed on the surface of the catalyst, thus enhancing the adsorption of the catalysts to the reactants and contact possibility of the reactants with the metals. The activity of the catalysts is influenced by the metals content and preparation temperature, and the coal gangue char prepared at 800 °C (CG-800) exhibits the highest catalytic activity in this work. At a reforming temperature of 700 °C, the conversion efficiency of biomass pyrolysis tar reaches 91.2% using CG-800 as the catalyst with a high total syngas yield of 516 mL/g. Moreover, part of the metal oxides in the catalysts can be reduced by the reducing gases during the tar reforming process, which can further help the catalysts maintain high catalytic activity in the recycling process. During the five-time reuse, the catalysts exhibit excellent stability with only a slight loss in tar conversion and total gas yield.

Dynamic Development of Biomass Char Porosity Modeling During Gasification

Dynamic Development of Biomass Char Porosity Modeling During Gasification

Combustion characteristics and synergistic effects during co-combustion of lignite and lignocellulosic components under oxy-fuel condition

Co-combustion of lignocellulosic biomass and coal has been recognized as a promising route to deliver carbon neutrality. In this study, the combustion characteristics of lignocellulosic biomass main components (cellulose, hemicellulose, and lignin), one kind of lignite, and their mixtures were investigated under air and oxy-fuel conditions, respectively. The combustion reactivity of cellulose and hemicellulose was better than that of lignite, while that of lignin was worse. Under the oxy-fuel condition with the same oxygen mole fraction as air, the combustion of cellulose and hemicellulose was slightly delayed, while a distinct combustion delay was observed for lignin similar to lignite. For the co-combustion, compared to lignite, the combustion reactivity could be improved by blending cellulose and hemicellulose, while it got worse by mixing lignin. Cellulose and hemicellulose had a positive synergistic effect on the release of lignite volatiles, while lignin showed a negative synergy on it. All the lignocellulosic components showed positive synergies with lignite on the char oxidation due to the high structural porosity of lignite char and the advanced oxidation of lignocellulosic char.

Fe–Co based synergistic catalytic graphitization of biomass: Influence of the catalyst type and the pyrolytic temperature

To produce porous graphite and hydrogen sustainably, a series of monometallic catalysts (e.g., Fe, Co, and Ni) and bimetallic catalysts (e.g., Fe–Co, Fe–Ni) were investigated for biomass graphitization. Experiments were conducted in a vertical fixed-bed system, and the influence of the catalyst type and the pyrolytic temperature were investigated. Further, the obtained sustainable porous graphite was employed in the oxygen reduction reaction. The results showed that the hydrogen yield, degree of char graphitization, and porosity changed when the catalyst type is varied. Among the monometallic catalysts, Fe showed a high degree of char graphitization and the largest surface area, while Co showed the highest hydrogen yield (7.19 mmol/g biomass). Due to the presence of Fe–Co alloys and the homogeneous distribution of Fe and Co, the bimetallic Fe–Co catalyst afforded a higher hydrogen yield (7.51 mmol/g), larger pore volume, and higher degree of char graphitization than the monometallic Fe and Co catalysts. The optimal pyrolytic temperature was found to be 850 °C, which ensured a balance between the char porosity and graphitization. Furthermore, the porous graphite obtained with the Fe–Co catalyst exhibited an outstanding electrochemical performance for the ORR, delivering a half-wave potential of 0.79 V under alkaline conditions, and high stability and outstanding electrochemical performance in the oxygen reduction reaction.

Performance of elemental mercury removal by activated char prepared from high-chlorine Turpan-Hami coal

This paper provides a new thought that a cost-effective chlorine-rich carbon-based sorbent could be prepared by directly pyrolyzing high chlorine coal in order to capture the elemental mercury, simultaneously realizing value-added utilization of the remained char instead of combustion during low rank coal pyrolysis poly-generation. In this work, the concentration and forms of chlorine in one kind of Turpan-Hami coal were determined quantitatively according to the proposed procedures. Then the release behavior of chlorine and the transformation of chlorine from inorganic state to organic were investigated during coal pyrolysis from 400 to 1000 °C. Moreover, the Hg0 removal performance was examined in a lab-scale fixed bed reactor by the char before and after CO2 activation. The results indicate that over 90 % of chlorine in raw coal is inorganic in the forms of ionic Cl and crystal NaCl, and ionic Cl can be transformed to inorganic NaCl and organic C-Cl species during coal pyrolysis, thus providing chlorine active adsorption sites for Hg0 chemisorption based on the results of temperature programmed desorption and adsorption kinetic analysis. Furthermore, CO2 activation can improve the char porosity and specific surface area, thus promoting the external mass transfer of Hg0 by increasing the opportunity of chlorine active sites being exposed to vapor Hg0. 100 % of Hg0 removal efficiency is achieved in the first hour and equilibrium adsorption amount is 400 ug/g for the activated char obtained by pyrolyzing coal at 600 °C combining with CO2 activation at 900 °C, indicating the good Hg0 removal performance of the as-obtained chlorinated activated char.

Comprehensive Assessment of Particle-Scale Modeling for Biomass Pyrolysis: One-Dimensional versus Three-Dimensional Models

The present work examines the impact of the dimensionality of single-particle models (SPMs) for the pyrolysis of thermally thick biomass particles. It builds up comprehensive one- and three-dimensional SPMs and assesses their performances to gain a systematic understanding of the accuracy of predicted results, predictive capability, and computational costs. Cylindrical wheat straw pellets with an average size of 10 mm length and 7 mm diameter were studied on their pyrolysis performances at temperatures ranged from 200 to 700 °C. It investigates the correlation between the inner heating rate of the particle and the resulting irregular porosity distribution in the pyrolyzed particle. The predictions of the models are in good agreement with the experimental measurement, and they show that the predicted char yield is not sensitive to the model dimensionality; however, the rate of mass loss and the char porosity are sensitive to the model dimensionality. Additionally, the three-dimensional SPM is found to be compatible with a wider range of biomass types. The model captures a higher heating rate at the surface and at the center of the particle compared to the region in between. This is linked to an uneven porosity distribution in the pyrolyzed particle, which is higher at the surface and at the center of the particle. While the three-dimensional SPM provides a small improvement in the prediction of the temperature profile compared to the one-dimensional model but offers additional details (e.g., temperature distribution, heating rate, and porosity distribution inside the particle); it requires significantly greater computational times, which might not be justifiable in many situations.