Parallel First-order Reactions Research Articles

Pseudo Master Curve Analysis of an Infinite Number of Parallel First-Order Reactions: Improved Distributed Activation Energy Model.

The so-called Distributed Activation Energy Model (DAEM) has been used extensively, mainly to analyze pyrolysis reactions of solid reactants. The model expresses many parallel first-order reactions using the distributions of activation energy f(E) and frequency factor k 0(E). Miura and Maki presented a method to estimate both f(E) and k 0(E) in the DAEM in 1998. This model has been used successfully by many researchers. In this paper more general basic equations are derived for describing an infinite number of parallel first-order reactions by extending the basic equations for the finite number of parallel first-order reactions. Revisiting the Miura-Maki method based on the general basic equations, a graphical analysis method that may be called "Pseudo Master Curve Analysis" is presented. The method not only supplements the Miura-Maki method but gives the underlying concept of the Miura-Maki method clearly. It is also shown that the graphical method can be applicable to analyze single reactions and the experimental data obtained using isothermal reaction techniques. Next, a method that improves the estimation accuracy of k 0(E) is presented. Practical examples analyzing several experimental data are also given to show the usefulness and validity of the Miura-Maki method and the graphical method. Through the examination, it is proposed that the DAEM should be renamed, for example, as the Distributed Rate Constant Model (DRCM).

The implication of kinetics characteristics of modern organisms for the hydrocarbon generation evolution of organic matter components in the lacustrine source rocks: A case study of the Dongying Formation from the Bozhong Sag, Bohai Bay Basin

The hydrocarbon generation evolution characteristics of lacustrine source rocks are crucial for understanding hydrocarbon resources. In this research, we focus on the mudstone found in the third member of the Paleogene Dongying Formation (E3d3) within the Bozhong Sag of the Bohai Bay Basin as a case study. An analysis of the discrepancy in geochemical characteristics and kinetic parameters was carried out by utilizing the modern organisms (pine pollen and benthic algae) analogies to the organic matter (OM) components (Pinaceae sporopollen and benthic algae amorphous). Furthermore, the bulk hydrocarbon evolution of the Dongying Formation mudstones was further discussed in combination with a water-added sealing thermal simulation experiment and basin simulation. Our findings indicate that the pine pollen and benthic algae have higher OM abundance compared to the E3d3 mudstones, and their OM types are both Ⅱ1-Ⅱ2, which possess excellent potential for oil generation. In contrast, the E3d3 mudstones are predominantly in the low mature to mature thermal evolution stage. When we compare hydrocarbon generation rates and transformation ratios using Rock-Eval pyrolysis, it becomes evident that modern organisms are more prone to generate large amounts of hydrocarbons even at a low mature stage. The kinetic parameters of pine pollen are notably higher compared to those of benthic algae and the E3d3 mudstone samples. In parallel first-order reactions, the activation energy obtained by the single-frequency factor model (SFFP model) displays a narrow distribution range, while the activation energy distribution range of the multi-frequency factor model (MFFP model) is broader. The MFFP model focuses more on the variations of hydrocarbon kinetic parameters throughout the entire process, which is more in conformity with the actual geological process. The enclosed thermal simulation experiment and basin simulation analysis unveil the presence of two distinct phases of hydrocarbon generation within the Dongying Formation. Furthermore, it becomes evident that abundant benthic algae and Pinaceae sporopollen components play vital roles in both of these phases. In conclusion, the method of applying modern organisms to analogize the hydrocarbon generation evolution characteristics of the parent components of lacustrine source rocks seems feasible. Meanwhile, the Dongying Formation in the Bozhong Sag also possesses broad exploration prospects for hydrocarbon resources.

Study on Pyrolysis-Mechanics-Seepage Behavior of Oil Shale in a Closed System Subject to Real-Time Temperature Variations.

In situ mining is a practical and feasible technology for extracting oil shale. However, the extracted oil shale is subject to formation stress. This study systematically investigates the pyrolysis–mechanics–seepage problems of oil shale exploitation, which are subject to thermomechanical coupling using a thermal simulation experimental device representing a closed system, high-temperature rock mechanics testing system, and high-temperature triaxial permeability testing device. The results reveal the following. (i) The yield of gaseous hydrocarbon in the closed system increases throughout the pyrolysis reaction. Due to secondary cracking, the production of light and heavy hydrocarbon components first increases, and then decreases during the pyrolysis reaction. The parallel first-order reaction kinetic model shows a good fit with the pyrolysis and hydrocarbon generation processes of oil shale. With increasing temperature, the hydrocarbon generation conversion rate gradually increases, and the uniaxial compressive strength of oil shale was found to initially decrease and then increase. The compressive strength was the lowest at 400 °C, and the conversion rate of hydrocarbon formation gradually increased. The transformation of kaolinite into metakaolinite at high temperatures is the primary reason for the increase in compressive strength of oil shale at 400–600 °C. (ii) When the temperature is between 20 and 400 °C, the magnitude of oil shale permeability under stress is small (~10−2 md). When the temperature exceeds 400 °C, the permeability of the oil shale is large, and it decreases approximately linearly with increasing pore pressure, which is attributed to the joint action of the gas slippage effect, adsorption effect, and effective stress. The results of this research provide a basis for high efficiency in situ exploitation of oil shale.

Hydrocarbon generation kinetics and in-situ conversion temperature conditions of Chang 7 Member shale in the Ordos Basin, China

In-situ conversion technology has been more popular lately as an effective way to realize the industrial development of extensive medium- and low-mature shale oil/oil shale resources in China. The Ordos Basin has been recognized as the main basin containing the largest in-situ conversion recoverable resources of China. Researchers have revealed the hydrocarbon generation kinetics of low mature oil shales in the 7th Member of the Yanchang Formation (Chang 7 Member). However, the kinetics of medium mature shales may be different from those of low mature shales, and they can also be used as potential targets for in-situ conversion. At present, there is a lack of research on the in-situ hydrocarbon generation kinetics of medium- and low-mature shale oil/oil shale. In this paper, open system pyrolysis experiments were carried out on natural shales and shale samples derived from semi-open system pyrolysis with different maturities in the Chang 7 Member of the Ordos Basin respectively. Using the parallel first-order reaction theory, the frequency factor of low-mature shale was calculated to be 5.47 × 1010 s−1, and the distribution of activation energy ranged from 38 kcal/mol to 61 kcal/mol. The main peak of activation energy was 49 kcal/mol, and accounted for 66.91% of all shales. With the increase in maturity, the average activation energy becomes higher, and therefore more in-situ conversion energy is needed. At the same time, the hydrocarbon generation potential characterized by S2 peak of pyrolysis decreases during the maturation process. The activation energy is divided into three groups according to its distribution characteristics: low, main peak and high activation energy groups, representing <47 kcal/mol, ranging from 47 kcal/mol to 52 kcal/mol and >52 kcal/mol respectively. The proportion of low and high activation energy groups increased with the increase in maturity, while the proportion of main peak activation energy groups decreased. When the kinetic parameters are extrapolated to the condition of in-situ conversion, it is better to choose shales with low maturity (RO <1 .0%) and fully transform them by rapid heating to the main hydrocarbon generation stage, and different conversion temperature ranges should be set for different maturity samples.

Kinetic and thermodynamic analyses for pyrolysis of hemp hurds using discrete distributed activation energy model

In many counties, hemp is becoming a high-valued economic crop. Post-processing, more than 65% w/w of its starting material becomes waste. Herein, pyrolysis of hemp hurds/residues was investigated under low (10–50 °C/min) and intermediate (100–150 °C/min) heating rates using a discrete distributed activation energy model (DAEM). Thermochemical decomposition of hemp hurds occurred in three stages: drying, active pyrolysis, and char formation, accounting for 70–80% w/w overall weight loss. With the discrete DAEM, the model can be utilized for predicting pyrolysis behaviors of hemp hurds accurately with correlation coefficient of over 0.99. Different reaction mechanisms appeared between the low and intermediate heating rates with 60 and 25 parallel first-order pyrolytic reactions detected, respectively. Under low heating rates, the pyrolysis showed high reactivity. The activation energy (E) and enthalpy change (ΔH) varied within 240–320 kJ/mol. The Gibbs free energy (ΔG) was 120–200 kJ/mol. The entropy change (ΔS) was 120–300 J/mol∙K. Under intermediate heating rates, the reactions were close to thermodynamic equilibrium and stability. The E and ΔH fluctuated from 80 to 250 kJ/mol. The ΔG was within 160–200 kJ/mol. The ΔS was between −100 and 100 J/mol∙K.

Evaluation of the number of first-order reactions required to accurately model biomass pyrolysis

Thermogravimetric analysis (TGA) experimental measurements, combined with modeling techniques, are widely employed for the characterization of the pyrolysis process of all kinds of biomass. The present work evaluates the number of reactions required to accurately model the pyrolysis process of lignocellulosic biomass, microalgae, and sewage sludge. A model with different number of parallel first-order reactions, from a single reaction up to ten reactions, is tested to fit the experimental TGA pyrolysis results, obtained for constant heating rates, and to determine the required optimal number of reactions for each type of biomass. The results show that the optimal number of reactions to precisely model the kinetics of lignocellulosic biomass is 5, whereas a model of 6 reactions is optimal for the characterization of microalgae and 8 reactions are required to accurately model the pyrolysis of sewage sludge. The outcome of the model, expressed in terms of the pyrolysis kinetics parameters and the relative contribution of each of the parallel reactions on the overall process, can be successfully extrapolated to the use of inverse exponential temperature increases, which are characteristic of pyrolysis processes occurring in isothermal reactors. Under these circumstances, the model is also capable of accurately reproducing the experimental results for all the different maximum temperatures and exponential temperature increases tested, demonstrating its robustness and applicability to pyrolysis processes occurring under non-linear temperature increases.

Formulation of the Heat Generation Rate of Low-Temperature Oxidation of Coal by Measuring Heat Flow and Weight Change at Constant Temperatures Using Thermogravimetry–Differential Scanning Calorimetry

This work successfully measured heat generation rates accompanying the air oxidation of three low-rank coals at seven constant temperatures ranging from 50 to 150 °C using a thermogravimetry–differential scanning calorimetry analyzer. The heat generation rates were well-expressed by the sum of three parallel first-order reactions, which are expressed by dQj/dt = kjQj0 exp(−kjt) (j = 1, 2, and 3), where Qj is the amount of heat generated, t is the time, kj is the first-order rate constant, Qj0 is the maximum amount of heat generated, and kjQj0 gives the maximum heat generation rate. The rate constants k1, k2, and k3 were well-represented by the Arrhenius equations. The activation energies were 2.78–7.58 kJ/mol for k1, 9.29–13.48 kJ/mol for k2, and 55.5 kJ/mol for k3. The maximum amounts of heat generated by reaction 3, Q30, were constants, irrespective of the temperature ranging from 340 to 671 kJ/kg of coal, as expected. On the other hand, Q10 and Q20 had to be regarded as variables increasing with the temperature. The calculated dQ/dt versus t relationships and Q versus t relationships using the estimated kj and Qj0 showed excellent agreements at all temperatures for all of the coals. This shows that the rate parameters obtained can well be used to represent the heat generation rate at temperatures between 50 and 150 °C. It was also found that the H2O-forming reaction with simultaneous formation of coal–oxygen complexes is the dominant process of the oxygen–coal interaction in the temperature range examined on the basis of the measurements of weight changes and formation rates of H2O, CO2, and CO.

Influence of coupling demineralization with the torrefaction pretreatment process on the pyrolysis characteristics and kinetics of rice husk

ABSTRACTThe influence of coupling demineralization with the torrefaction pretreatment process on the pyrolysis characteristics and kinetics of rice husk by a thermogravimetric analyzer was investigated in this work. It was found that demineralization has a positive effect on the volatile release, but torrefaction resulted in the reduced formation of volatiles during subsequent pyrolysis. The four independent parallel first-order reactions model was used to evaluate the pyrolysis kinetic parameters. It appears that rice husk, after coupling demineralization with torrefaction pretreatment, has a higher activation energy than that of raw rice husk.

Kinetic Model of Steam Gasification of Biomass in a Bubbling Fluidized Bed Reactor

A simple kinetic model is developed for biomass gasification in a bubbling fluidized bed (BFB) with steam as the fluidizing gas. The biomass pyrolysis is described by a two-step kinetic model in which the primary pyrolysis is modeled by three parallel first-order reactions producing noncondensable gas, tar (bio-oil), and char, and the secondary pyrolysis is modeled by a first-order reaction representing homogeneous thermal cracking of tar. In addition to the yields of pyrolysis products that are often modeled as lumped species, the proportions of major compounds in the pyrolysis gas are predicted based on CHO elemental balances. By incorporating homogeneous and heterogeneous biomass gasification reactions, a seamless kinetic model of a BFB gasifier is developed. An ideal reactor model is used for the BFB gasifier assuming perfectly mixed solids and plug flow of the gas phase. This predictive model is a useful tool to relate biomass gasification product yields and composition to key process operating param...

Coupled reactor and particle model of biomass drying and pyrolysis in a bubbling fluidized bed reactor

A comprehensive single particle model of biomass drying and pyrolysis is coupled with an ideal reactor model of a bubbling fluidized bed with nitrogen as the fluidizing gas. To predict biomass pyrolysis products yield and composition under steady-state operation, a two-step biomass pyrolysis kinetic mechanism is adopted with primary pyrolysis described by two different reaction kinetic schemes: (a) Three parallel first-order reactions producing primary pyrolysis products (non-condensable gas, tar/bio-oil and char), and (b) a detailed solid state kinetics mechanism based on multiple reactions of lignin, cellulose, and hemicellulose contents of two specific types of biomass (poplar and lodgepole pine). Secondary pyrolysis is modeled by two parallel reactions describing homogeneous thermal cracking of tar to non-condensable gas and char. In addition to the yields of pyrolysis products often modeled as lumped species, this model addresses an existing gap of knowledge in predicting the proportions of major compounds in the pyrolysis gas based on a few simplifying assumptions and CHO elemental balances. This predictive model is a useful tool to relate biomass pyrolysis products yield and composition to process operating parameters such as biomass ultimate analysis, reactor temperature, gas residence time, mean solids residence time inside the reactor, as well as biomass particle size and moisture content. Model predictions for the two kinetic schemes are in good agreement with available experimental data from the literature.

Kinetic modeling of five sustainable energy crops as potential sources of bioenergy

ABSTRACTFive energy plants from different regions of the world were pyrolyzed by non-isothermal thermogravimetry and effluent gases were detected through a mass spectrometer. Thermal decomposition characteristics, quantification of emissions, reactivity, and process kinetics were determined. Among the fuels tested, miscanthus was the most reactive, while jatropha was more heterogeneous. A first-order parallel reactions model fitted the experimental results with great accuracy. Miscanthus and willow can be characterized as high-quality fuels and produced higher amounts of carbon oxides and lighter hydrocarbons at lower temperatures. For jatropha, cardoon, and sunflower co-gasification or co-firing is suggested, in order to avoid nitrogenous emissions.

Kinetics of Sewage Sludge Pyrolysis and Air Gasification of Its Chars

Optimal management and utilization of sewage sludge require innovative technological solutions. One of the prospective and novel concepts for the utilization of this waste, targeted at energy production, is the two-stage process combining pyrolysis and gasification. The paper presents the kinetic analysis of sewage sludge pyrolysis and air gasification of “hot” chars with the application of the thermogravimetric analyzer SDT Q600. The pyrolysis was performed below 1173 K in the inert gas atmosphere and with various heating rates of 1, 10, 50, and 100 K/min. The air gasification of chars was performed at 973, 1073, or 1173 K. The lumped model, which encompasses six first-order parallel reactions, was indicated as the most appropriate for the interpretation of the kinetics of sewage sludge pyrolysis. For the description of the char gasification stage, the Avrami–Erofeev model (A3) was proposed. The kinetic parameters estimated on the basis of the experimental data are the first published for sewage sludge “...

Reaction kinetics of molecular aggregation of rhodamine 123 in colloids with synthetic saponite nanoparticles

The reaction kinetics of the molecular aggregation of rhodamine 123 in the colloids of synthetic saponite (Sumecton, Kunimine, Japan) was measured using a UV–Vis spectrophotometer equipped with a diode array detector with fast sampling and combined with a thermostatic stopped-flow device. The colloids exhibited a very small tendency to produce dye molecular aggregates, which can be explained by the low layer charge of saponite. Nevertheless chemometric methods, including principal component analysis and multivariate curve resolution, were able to sensitively identify spectral components. The reaction kinetics of dye aggregation followed the model, which was mathematically described by two-phase exponential functions, which indicated the presence of two parallel first-order reactions. Oblique aggregates were formed, characterized by approximate right angles between interacting transition moments. Another reaction, which was assigned to the structural changes of the aggregates, was detected after longer reaction times. The total span of the reaction was relatively low (~5%). The reaction was relatively fast, giving half-lives in the range 8–10s. Reaction kinetics parameters can be useful for the characterization of similar reactions occurring in dye/clay mineral colloidal systems.

Kinetics of carbonate mineral dissolution in CO2-acidified brines at storage reservoir conditions.

We report experimental measurements of the dissolution rate of several carbonate minerals in CO2-saturated water or brine at temperatures between 323 K and 373 K and at pressures up to 15 MPa. The dissolution kinetics of pure calcite were studied in CO2-saturated NaCl brines with molalities of up to 5 mol kg-1. The results of these experiments were found to depend only weakly on the brine molality and to conform reasonably well with a kinetic model involving two parallel first-order reactions: one involving reactions with protons and the other involving reaction with carbonic acid. The dissolution rates of dolomite and magnesite were studied in both aqueous HCl solution and in CO2-saturated water. For these minerals, the dissolution rates could be explained by a simpler kinetic model involving only direct reaction between protons and the mineral surface. Finally, the rates of dissolution of two carbonate-reservoir analogue minerals (Ketton limestone and North-Sea chalk) in CO2-saturated water were found to follow the same kinetics as found for pure calcite. Vertical scanning interferometry was used to study the surface morphology of unreacted and reacted samples. The results of the present study may find application in reactive-flow simulations of CO2-injection into carbonate-mineral saline aquifers.

High-temperature Shilov-type methane conversion reaction: Mechanistic and kinetic studies

Traditional Shilov reactions (performed in aqueous solution with a PtCl2 catalyst) for methane conversion suffer from catalyst deactivation at high temperatures (> 100 °C), therefore only very low conversion rates have been achieved. In this paper, we show that Shilov-type C–H activations are achievable at much higher temperatures (∼200 °C) by addition of concentrated aqueous solutions of Cl− to inhibit Pt catalyst precipitation. Various chloride-based ionic liquids also stabilized the Pt catalyst at mild reaction temperatures (∼140 °C). Under high-pressure conditions (> 25.5 MPa), achieved using a specially designed sealed gold-tube reactor, very high methane conversion rates (> 90%) were obtained; this is attributed to the improved methane solubility in aqueous solution. Deuterium isotope (H/D) exchange between methane and water was used to examine the reaction reactivity and selectivity. Multiply D-substituted products were observed, indicating that multiple C–H activations occurred. A comprehensive network reaction that included all the chain reactions was set up to clarify the reactivities and product selectivities of the methane activation reactions. The reaction network consisted of a series of parallel first-order reactions, which can be described by the Arrhenius equation. The kinetic parameters such as the frequency factor, activation energies, and stoichiometric coefficients were obtained by fitting the experimental data. Because all four C–H bonds in a methane molecule are equivalent, multiple substitutions during methane conversion cannot be avoided. Our studies indicate that mono-substituted and di-substituted methane isotopologue generations have similar activation energies, suggesting that the highest mono-substitution selectivity cannot be greater than 50%.

Pyrolysis kinetics of oil shale from northeast China: Implications from thermogravimetric and Rock–Eval experiments

Thermogravimetric analysis (TGA) is used extensively to study oil shale pyrolysis and kinetics. TGA measures the total weight loss of the sample during pyrolysis, including the decomposition of kerogen and minerals, as well as the removal of water from clays. Rock–Eval (RE) characterizes the hydrocarbon released during pyrolysis. In order to identify and quantify the stages of kerogen decomposition and other reactions during pyrolysis, we performed TGA and RE pyrolysis experiments at four heating rates (10, 20, 30, and 40°C/min) on two oil shales from Huadian and Fushun in northeast China. We determined the kinetic parameters of oil shale pyrolysis by applying parallel first-order reaction models to data from TGA and RE experiments. Variations in pyrolysis temperature and activation energy occur across the two experimental methods. Most weight loss and hydrocarbon generation occurred between 400 and 550°C using TGA, and between 400 and 475°C using RE. For the Huadian oil shale, the average amount of weight loss and hydrocarbon generation across all heating rates were 151.32 and 73.48mg/g, respectively; the corresponding values for Fushun oil shale are 151.97 and 34.02mg/g. For the Huadian oil shale, kerogen decomposition occurred mainly in the temperature range of 300–500°C. The contribution to weight loss of kerogen decomposition was 14.7%, 48.6%, and 3.5% in the temperature ranges of 200–300°C, 300–500°C, and 500–600°C, respectively. Additional weight loss was caused by the decomposition of minerals such as smectite, kaolinite, and pyrite. The activation energies obtained by TGA span a greater range than those obtained by RE, and the average activation energies obtained by TGA are lower by 10kJ/mol (Huadian) and 1kJ/mol (Fushun) than those obtained by RE. The discrepancy between TGA and RE results indicates that non-hydrocarbon reactions are significant at temperatures between 200 and 600°C, and that RE is the more accurate approach for quantifying hydrocarbon generation during oil shale pyrolysis.

Cracking of Maya Crude Asphaltenes

Cracking of Maya crude asphaltenes was carried out in a batch reactor at the following reaction conditions: temperature of 380–410°C, total pressure of 2 MPa, and asphaltenes/catalyst ratio of 5 g/g using NiMo commercial catalyst. n-hexadecane was used to keep asphaltenes dispersed and reaction time ranged from 0 to 60 min. The products were lumped into four fractions: asphaltenes, maltenes, gases, and coke. A kinetic model assuming pseudo–first-order parallel reactions was used to fit the experimental data.

Kinetic Study of Subcritical Steam Gasification of Coal Using Calcium-Based Carbon Dioxide Sorbent

The subcritical steam gasification of coal was performed with a calcium-based CO2 sorbent (Ca(OH)2) in a laboratory-scale batch reactor to examine the gasification kinetics with respect to the effects of partial pressure of steam and coal quality. The study was intended to support the hydrogen production by a reaction-integrated novel gasification (HyPr-RING) process in which coal is gasified with subcritical steam in a fluidized bed containing Ca(OH)2. Conducting subcritical steam gasification at 600–727 °C and 3–20 MPa produced zero emissions of CO2 because the rate of CO2 sorption by Ca(OH)2 was faster than that of CO2 generation by gasification. The gasification reaction mechanism was represented by a parallel first-order reaction model of the components of volatiles and char in coal. Hydrogen was mainly produced via tar from volatiles. The optimal partial pressure of steam preferred for hydrogen generation was 3 MPa, rather than 20 MPa. More volatiles in coal increased hydrogen yield in the gasificat...

Pyrolysis characteristics of excavated waste material processed into refuse derived fuel

The pyrolysis characteristics of refuse derived fuel (RDF) processed from excavated landfill waste are investigated by thermogravimetric analysis combined with a MATLAB® optimization study to determine chemical kinetic parameters. Waste samples – a mix of municipal and industrial waste – with particle sizes between 150 and 250μm are heated to 800°C at a heating rate of 10°Cmin−1. The independent parallel first-order reactions model is used for the kinetic analysis. Four parallel reactions describe the thermal degradation behavior of the waste material. The calculated kinetic parameters (activation energy E=100, 149, 99, 353kJmol−1, resp.) for the four identified fractions (hemicellulose, cellulose, and two types of plastic) did not fully agree with experimental studies available in the literature for fresh waste materials. The first fraction closely resembles hemicellulose. The second fraction is similar to cellulose, but the broad peak could indicate that lignin degradation is also covered. The behavior of the third fraction (i.e. the least stable plastics) deviates from literature data. This is explained by the partial overlap between the decomposition range of the second and third fraction. The fourth fraction decomposes in the same way as the stable plastics. The characteristics of the excavated waste (composition, age, possible catalytic effect of mineral matter and metals, etc.) could provide an explanation for the differences observed when comparing with fresh waste.

Thermogravimetric Analysis and Kinetics on Reducing Low-Grade Manganese Dioxide Ore by Biomass

Nonisothermal thermogravimetric analysis (TGA) was applied to evaluate rice straw, sawdust, wheat stalk, maize straw, and bamboo to explore their potential for reduction of manganese dioxide ore. Results from the biomass pyrolysis experiments showed that wood-based biomass materials, such as sawdust and bamboo, could produce more reductive agents, while herb-based biomass materials, such as rice straw, wheat stalk, and maize straw, had lower reaction temperatures. The peak temperatures for biomass reduction tests were 20 K to 50 K (20 °C to 50 °C) higher compared with the pyrolysis tests, and a clear shoulder at around 523 K (250 °C) could be observed. The effects of heating rate, biomass/manganese dioxide ore ratio, and different components of biomass were also investigated. An independent parallel first-order reaction kinetic model was used to calculate the values of activation energy and frequency factor for biomass pyrolysis and reduction of manganese dioxide ore. For better understanding the reduction process, kinetic parameters of independent behavior of manganese dioxide ore were also calculated by simple mathematical treatment. Finally, the isokinetic temperature Ti and the rate constant k0 for reduction of manganese oxide ore by reductive volatiles of biomass were derived according to the Arrhenius equation, which were determined to be 603 K (330 °C) and 108.99 min−1, respectively.