Values Of Equivalence Ratio Research Articles

Fluidized bed gasification of eucalyptus chips: Axial profiles of syngas composition in a pilot scale reactor

Air gasification tests have been carried out in a pilot scale bubbling fluidized bed gasifier, able to treat up to 100 kg/h of Eucalyptus wood chips, and operated, under chemical and thermal steady-state conditions, at different values of equivalence ratio. The results are reported in terms of the main process performance parameters and transfer coefficients, which indicate the fate of carbon in the different output streams (syngas, fines, tars). The results can be transferred to commercial scale reactors and confirm the technical feasibility of the air gasification of the biomass in the range 0.25–0.34 of equivalence ratio, yielding a good quality syngas, with a low heating value between 5000 and 6000 kJ/m3N,syngas. The measured axial syngas composition profiles along the reactor indicate a monotonic reduction of methane and carbon dioxide concentrations and an increase of that of hydrogen. This suggests that water gas shift and steam and dry reforming reactions play a significant role, together with a limited contribution of tar cracking reactions, probably enhanced by alkali and alkaline earth metallic species contained in the inorganic fraction of elutriated fines. Results can support the implementation of reliable numerical models of bubbling fluidized bed gasifiers and the optimisation of design/operating criteria.

CFD-DEM simulation of air-blown gasification of biomass in a bubbling fluidized bed gasifier: Effects of equivalence ratio and fluidization number

In this study, air-blown gasification of biomass in a bubbling fluidized bed (BFB) gasifier was numerically investigated. A discrete element model coupled with computational fluid dynamics (CFD-DEM), in which gas is considered as continuum and particle is considered as discrete phase, was employed. The flow characteristics of the BFB were discussed and compared with the reported experimental data. Then, the gasification performance of the BFB was discussed for cases with varying fluidization number (FN) values at a constant equivalence ratio (ER). In a parametric study, calculations were performed for various FN values, and the ER value was fixed as 0.27. The formation of CO2 commenced inside the fluidized bed region for FN values exceeding 3.6. When the FN value increased, slight decreases were observed in the CO and H2 concentrations as well as CCE. Thus, an increase in FN beyond a certain value was not recommended. Another parametric study was performed for various combinations of FN & ER values. The CGE increased for FN & ER values between 2.49 & 0.21 and 3.56 & 0.3, whereas it decreased for FN & ER values exceeding 3.56 & 0.3. Therefore, the optimum FN & ER values were considered as 3.56 & 0.3.

Exergy analysis of updraft and downdraft fixed bed gasification of village-level solid waste

The most commonly used for gasification of village-level solid waste is the fixed-bed gasifier, but there is no reasonable method to evaluate the gasification process. This paper attempts to find a gasifier that is most suitable for gasification of village-level solid wastes through exergy analysis method. Based on experimental data from literature, the exergy efficiencies and LHV(Low Heat Value) of product gas from updraft and downdraft fixed bed gasifier are studied in this paper. The results show that the updraft fixed bed gasifier has higher exergy efficiency, and the gas produced by the downdraft fixed bed gasifier has a higher heating value. Air gasification has higher exergy efficiency than steam gasification and pure oxygen gasification. The highest exergy efficiency at a gasification temperature of about 1000 °C and ER (Equivalence Ratio) value in the range of 0.33–0.36. The volatile content of gasification raw materials is higher, and the gasification efficiency is higher. Through the research of this paper, a new path to reasonably evaluate the gasification process is obtained.

Wall Roughness Effects on Combustion Development in Confined Supersonic Flow

Reactive and nonreactive Reynolds-averaged Navier–Stokes simulations of hydrogen injection into a confined transverse supersonic flow of vitiated air are conducted. The corresponding conditions were studied in the LAPCAT-II combustor. Two operating conditions are considered, which differ in the value of the momentum ratio between the hydrogen and vitiated air inlet streams, thus leading to two distinct values of the equivalence ratio (ER). For its smallest value, smooth combustion develops subject to a preliminary thermal runaway period, while for its largest value, combustion is more strongly intertwined with shock wave dynamics and boundary layer separation. Special emphasis is placed on the possible effects of wall roughness on this reactive flow development. One among the conclusions of preliminary computational analyses of the present flowfield is that it may play a significant role on combustion development. This is firmly confirmed in the present study, which takes explicitly the influence of wall roughness into account within the equivalent sand grain modeling framework. For the largest ER value, the combustion stabilization mechanism is found to change dramatically whether roughness is taken into account or not. Its influence is assessed through a detailed comparison with available experimental data.

Synergistic effects of co-gasification of municipal solid waste and biomass in fixed-bed gasifier

The co-gasification of refuse derived fuel (RDF) and biomass is a promising technology for environmentally friendly municipal solid waste (MSW) utilization. Herein, we investigated the co-gasification of RDF and straw mixtures. The development of syngas suggested that higher temperature and equivalence ratio (ER) values promote syngas yield during gasification and co-gasification. Temperature plays a positive key role in gas yield and carbon conversion efficiency once the ER is higher than 0.3 during co-gasification. Except for an ER of 0.3, synergistic enhancements in carbon conversion efficiency, gas yield, and cold gas efficiency were observed for co-gasification. The positive synergistic effects of co-gasification mainly appeared in lower ER (0.1−0.2) and higher temperatures (800−900°C); however, the negative synergistic effects more tend to appear in higher ER (0.3−0.4). From the development of bottom ash in co-gasification, at higher temperature and ER values, potassium in the bottom ash was favored to stay in sulfur-containing compounds; whereas at lower temperature and ER values, potassium preferred to exist in potassium chloride. A higher calcium content more easily enriched in small particles that were integrated into aluminosilicate led to the formation of sticking ash particles, which could promote significant melting agglomeration. However, these melting agglomerations could be suppressed by adding straw into the RDF. These results provide a feasible method for the resource utilization of MSW.

Numerical simulation of the effects of hydrogen and carbon monoxide ratios on the combustion and emissions for syngas fuels in a radiant burner

In this study, the performance of a gas-fired radiant-tube which was fuelled with syngas and air mixtures was investigated numerically using ANSYS Fluent version 17.2. The burner was operated in a non-premixed mode with swirled air. The exhaust emissions of nitrogen oxides (NOx) and carbon monoxide (CO) as well as the temperature distributions along the radiant tube were analysed for three different syngas fuels which were composed of hydrogen (H2) and CO, with ratios (by vol.) of 75:25, 50:50, and 25:75. The simulations were conducted at equivalence ratio values of 0.82, 0.7 and 0.5, while the air flow Reynolds numbers were set to 5400, 6320 and 8850. Based on the simulation results under all the tested conditions, it was found that the 75H2:25CO syngas fuel performed better, where the non-uniformity parameter calculated for this fuel was 35% lower than that of the 25H2:75CO. In terms of CO emissions, 75H2:25CO had the lowest value among the tested fuels, where the maximum difference as compared to that of the 25H2:75CO was up to 93%. Meanwhile, the NOx emissions predicted for 75H2:25CO were approximately 67% lower than those of the 25H2:75CO.

An experimental investigation on combustion and performance characteristics of supercharged HCCI operation in low compression ratio engine setting

This study investigates the effects of boost pressure on combustion and performance of an early direct injection homogenous charge compression ignition (HCCI) engine at a low compression ratio (CR). A 2.0 L, four-cylinder, four-stroke, gasoline direct injection engine was converted to operate in early direct injection HCCI mode. In addition, a supercharger unit was developed for engine boosting. The experiments were performed at different intake manifold absolute pressures (MAP) from 1.0 to 1.6 bar at different engine loads using n-heptane fuel. The effects of boost pressure were investigated on HCCI combustion and engine performance characteristics using volumetric efficiency, in-cylinder pressure, heat release rate (HRR), maximum in-cylinder pressure and gas temperature, CA50 (crank angle by which 50% of the fuel is burnt), combustion duration, apparent combustion efficiency, indicated mean effective pressure (IMEP), brake mean effective pressure (BMEP), friction mean effective pressure (FMEP), indicated thermal efficiency (ITE), brake thermal efficiency (BTE), heat loss, exergy of heat loss, coefficient of variation of IMEP (COVIMEP), maximum pressure rise rate (MPRR) and ringing intensity (RI). The experimental results showed that high-efficiency HCCI operation is feasible at an engine compression ratio as low as 9.2 once the engine variables are properly optimized and an appropriate level of supercharging is utilized. An increase in indicated thermal efficiency was seen as boost pressure increased. In addition, combustion phasing advanced by increasing boost pressure or increasing air–fuel equivalence ratio values. Combustion events with CA50 2–3 °CA aTDC show the highest thermal efficiency especially at low boost pressure conditions. In addition, the pressure rise rate and ringing intensity increased by increasing air–fuel equivalence ratio and MAP. The test results also showed that HCCI operating range can be extended with the increase of intake manifold pressure especially at high load limits.

Thermodynamic Analysis of Superheated Steam and Flue Gas as Drying Agents for Biomass Dryers

Bagasse is a sugarcane byproduct of high moisture content that usually requires drying before its use in the production of heat, power, fuels, and chemicals. This work explores the possibility of replacing flue gas, a hazardous heat source, with steam in bagasse rotary dryers using Aspen Plus v8.6 as a simulation tool. In the simulation, a bagasse-fed combined heat and power (CHP) plant generated superheated steam at 2 bar and flue gas, and both acted as drying agents in zero-dimensional biomass dryers that reduced bagasse moisture from 50 to 10 wt.%.The biomass final moisture content is inversely proportional to the drying agent temperature and flow rate. Steam dryers required a steam-to-wet-biomass ratio (S/WetBiom) of 4.0 with 2-bar steam at 260 °C to achieve a steam-to-evaporated-moisture (S/EvapMoist) ratio of 9.0, which is suggested for steam as a drying agent. For flue gas dryers, the equivalence ratio (ER) played an essential role: higher ERs increased the O2 content in flue gas, reducing the gas higher heating value (HHV), and increasing the amount of flue gas required per unit of evaporated moisture (FG/EvapMoist). Thus, ER values of 1.1 were advised to counterbal-ance the effects of ER and still provide enough excess air to allow complete fuel combustion in the CHP furnace. As the flue gas exiting the furnace presented extremely high temperatures (~1550 °C), this stream was cooled down to the superheated steam temperature (260 °C), and drying performances were compared. Although flue gas had an HHV lower than the steam latent heat, it presented higher production yields, resulting in lower bagasse combustion requirements in the CHP to provide enough drying agent per kg of dried biomass in flue gas dryers. Nevertheless, if the CHP system adopts steam split ratios in the range of 0–0.2 and alternative steam sources are available in the biorefinery, steam can be an attractive drying medium for biomass dryers.

A Numerical Investigation of the Minimum Ignition Energy Requirement for Forced Ignition of Turbulent Droplet-laden Mixtures

ABSTRACT The effects of droplet diameter, overall (i.e. liquid and gaseous phases) equivalence ratio, and turbulence intensity on the variation of the Minimum Ignition Energy (MIE) for localized forced ignition of uniformly dispersed mono-sized n-heptane droplet-laden mixtures under homogeneous isotropic decaying turbulence have been analyzed based on Direct Numerical Simulation (DNS) data. The MIE was evaluated just for (i) obtaining thermal runway irrespective of the fate of the resulting flame kernel, and (ii) also for a successful self-sustained flame propagation without the assistance of an external energy source following the energy deposition by the ignitor. It has been found that the MIE requirement increases with increasing turbulence intensity and this trend for the MIE increase is especially significant for large values of turbulence intensity. The MIE requirement increases with increasing initial droplet diameter and with decreasing overall equivalence ratio. The MIE requirements for droplet-laden mixtures have been found to be greater than the corresponding value for homogeneous mixture with the same nominal values of initial turbulence intensity and equivalence ratio for the parameter range considered here. This behavior arises due to the deposited energy being partially utilized to supply the latent heat of evaporation and also due to the predominantly fuel-lean composition of the gaseous flammable mixture. This tendency of obtaining fuel-lean mixture strengthens with increasing (decreasing) initial droplet diameter (overall equivalence ratio). It has also been demonstrated that combustion takes place predominantly in the fuel-lean premixed mode although there is a finite probability of having non-premixed combustion in all cases. Moreover, there is a small probability of fuel-rich combustion occurring for small droplets, especially under fuel-rich overall equivalence ratios. The stochastic nature of the ignition event has been demonstrated by considering different realizations of statistically similar turbulent flow fields. The conditions giving rise to a successful thermal runaway/self-sustained flame propagation have been identified by a detailed analysis of the energy budget.

Thermodynamic assessment of the oxidative steam reforming of biomass fast pyrolysis volatiles

The joint process of pyrolysis-steam reforming is a novel and promising strategy for hydrogen production from biomass; however, it is conditioned by the endothermicity of the reforming reaction and the fast catalyst deactivation. Oxygen addition may potentially overcome these limitations. A thermodynamic equilibrium approach using Gibbs free energy minimization method has been assumed for the evaluation of suitable conditions for the oxidative steam reforming (OSR) of biomass fast pyrolysis volatiles. The simulation has been carried out contemplating a wide range of reforming operating conditions, i.e., temperature (500–800 °C), steam/biomass (S/B) ratio (0–4) and equivalence ratio (ER) (0–0.2). It is to note that the simulation results under steam reforming (SR) conditions are consistent with those obtained by experiments. Temperatures between 600 and 700 °C, S/B ratios in the 2–3 range and ER values of around 0.12 are the optimum conditions for the OSR under autothermal reforming (ATR) conditions, as they allow attaining high hydrogen yields (10 wt% by mass unit of the biomass in the feed), which are only 12–15% lower than those obtained under SR conditions.

Syngas production strategies from biomass gasification: Numerical studies for operational conditions and quality indexes

Gasification is an enhanced thermal technique, as it affords a versatile synthetic gas (syngas) from which it is possible to obtain various commodity assets such as electricity, fuels and chemicals while conveniently disposing of biomass or waste residues.To the best of the authors’ knowledge, there are no publications thoroughly relating syngas quality features with its possible applications. The report of quality indexes for syngas is quite scarce once they depend on quality indicators which are difficult to reconcile and simultaneously adjust to meet the expected syngas characteristics. Therefore, in an attempt to fill this gap, this work reports the gasification modelling for miscanthus (M), peach stone (PS) and a mixture of polyethylene terephthalate and vine pruning (PET-VP) in order to determine syngas quality indicators and potential applications. The operational conditions were optimized through a parametric study for the achievement of high-quality syngas, varying temperature (T), equivalence ratio (ER) and steam to biomass ratio (SBR) and assessing the lower heating value (LHV), cold gas efficiency (CGE) and tar content.The main trends for the assessed parameters show improved calorific content for higher temperatures (800 °C – 850 °C), lower ER (0.2–0.25) and moderate SBR values (around 2.0). PET-VP displayed the higher LHV (around 9 MJ/Nm3) except when SBR was varied. In this case, M afforded enhanced calorific content (6.5 MJ/Nm3) which rapidly decreased for higher ratios. Conversion efficiencies of 70–80% were seen for the studied feedstocks and tar content was seen to decrease for higher temperatures, higher ER and higher SBR. PET-VP enabled the manufacture of chemicals and fuel gas, while M and PS originated syngas capable of producing synthetic fuels.

Experimental Study of Continuous H2/Air Rotating Detonations

ABSTRACT An experimental study of a lab scale rotating detonation combustor (RDC) has been conducted to identify and classify its modes of operation under different feeding conditions. The chamber uses air as oxidizer and hydrogen as fuel. The stability diagram of the RDC has been determined based on the detonation chamber Reynolds number and reactants mixture equivalence ratio values. The Reynolds number is based on the air volume flow rate, chamber annulus size, and the reactants mixture feeding slot area. Hence the effects of geometrical parameters and operational parameters on the detonation wave stability can be presented in a single stability map. This diagram identifies different zones in terms of the stability, propagation characteristics, and the number of detonation waves. Absence of a stable detonation wave at low Reynolds numbers and observation of different detonation modes with increasing Reynolds number, in different ranges of equivalence ratios, have been established in this research. This paper describes the various modes of rotating detonation wave propagation in the RDC. These modes include the single-wave detonation mode, the dual-waves unidirectional detonation mode, the dual-waves colliding detonation mode, extinguishing and re-initiating detonation mode, and the deflagration mode

Application of the Sectional Method to Investigate Particle Number and Soot Mass in Ethanol and Gasoline Fueled Premixed Spark Ignition Engines

Emission modelling is still a timely topic in the engine research community. Soot emission reduction has gained its spotlight among the pollutants-related issues mainly due to the renewed interest in Gasoline Direct Injection. The conjunction of experimental measurements and numerical investigations provides an effective tool to cope with the constant evolution of the emission regulations. Thus, numerical models must be validated over a wide range of engine operating points and fuels. To this aim, the Sectional Method was applied to investigate Particulate Matter and Particle Number produced during combustion in a premixed spark ignition engine using 3D-CFD. Soot-related quantities were investigated for different values of equivalence ratio (from 1.0 up to 1.5) as well as for different fuels. Three different fuel types were examined: a commercial nonoxygenated American gasoline (TIER-2), a commercial Chinese gasoline (CHINA-6) with ethanol 10 %vol and pure Ethanol (E100). A detailed chemistry-based tabulated approach was exploited to compute a dedicated soot library, for each of the analyzed fuels, by means of 0D chemical kinetic simulations using a constant pressure reactor approach. Numerical results were compared to a database of experimental measurements collected from literature. The sooting tendency threshold dependency on equivalence ratio was also investigated and the results showed that the ethanol is the less sooting among the examined fuels, while the non-oxygenated gasoline exhibited the highest soot mass and Particle Number. This paper provides a CFD-based benchmark for soot mass and Particle Number for three fuel types with largely different chemical nature.

Integrating food waste sorting system with anaerobic digestion and gasification for hydrogen and methane co-production

Anaerobic digestion (AD) is a potential biotechnology to treat food waste for both energy and resource recovery. However, a high level of contamination in food waste limits their direct use as feedstocks. Therefore, a food waste sorting system followed by anaerobic digestion and gasification is proposed in this study to evaluate the potential of food waste for hydrogen and methane co-production through the thermal-equilibrium model and experimental study. To achieve the H2-rich syngas and methane-rich biogas, the waste sorting system was used to separate the raw waste into pure food waste fraction for AD and discarded waste fraction for gasification. The thermal-equilibrium model is used to predict the content of H2 at different moisture content and air equivalence ratio (ER). The results show that gasification generated the highest hydrogen content at 28.9% with a high moisture content of 55 wt% when the value of ER is 0.35. The highest calorific value of syngas is 5.59 MJ/m3 at the conditions of 60 wt% of moisture content and 0.35 of ER. For the mesophilic AD system, the highest specific methane yield of FW is 557 mL/g VS. Thermophilic AD increased methane yield to 680 mL/g VS while AD of vegetable waste had a negligible production of methane gas. The overall energy performance of the integrated AD and gasification system was assessed in terms of the output of electricity and heat.

Application of Non-Thermal Plasma for NOx Reduction in the Flue Gases

Over the years, ever more stringent requirements on the pollutant emissions, especially NOX, from combustion systems burning natural gas are introduced by the European Union (EU). Among all NOX reduction methods, the flue gas treatment by plasma is widely applied and could be used for both small scale and domestic combustion systems. However, the removal efficiency depends on concentrations of oxygen, water vapor, traces of hydrocarbons, and nitrogen oxides in flue gas. In order to analyze the application of the NOX reduction for small-scale or domestic combustion systems, experiments of NOX reduction by non-thermal plasma from real flue gases originating from premixed methane combustion at different equivalence ratio (ER) values were performed. It was determined that the residual oxygen in flue gas plays an important role for improvement of NO to NO2 oxidation efficiency when O2 concentrations are equal to or higher than 6%. The power consumption for the plasma oxidation constituted approximately 1% of the burner power. In the case of ozone treatment, the addition of O3 to flue gas showed even more promising results as NO formed during combustion was fully oxidized to NO2 at all ER values.

On the turbulent flow and pollutant emission characteristics of disk stabilized propane-air flames, under inlet mixture stratification and preheat

The reacting, time averaged and fluctuating flow field characteristics of bluff-body stabilized, stratified, propane-air flames have been systematically investigated for a range of conditions, under a combination of inlet mixture stratification and preheat. The burner consists of three concentric disks that form two premixing cavities. Fuel is injected in the first cavity and is partially premixed with air flowing through this cavity system, resulting in a radially stratified equivalence ratio profile at the inlet of the stabilization region. Investigations have been carried out at four levels of preheat temperatures, of the incoming reactants, ranging from 300 to 743 K, for lean and ultra-lean mixtures. The burner set up is capable of anchoring flames of sub-limit mixtures, down to global equivalence ratio values of about 0.13 at 743 K. The time averaged and fluctuating reacting velocity fields, developing in the downstream near wake, have been evaluated with Particle Image Velocimetry (PIV) analysis, indicating a proportionate decrease of the recirculation zone length with increasing fuel levels. OH∗ chemiluminescence emissions revealed a progressive alignment of the reacting front with the flame axis at weaker mixtures, while exhaust gas measurements have been obtained to evaluate the impact of preheat on emissions performance and combustion efficiency.

Effects of inversed-delta injection rate shaping on diesel spray flame liquid length, lift-off length and soot onset

In this paper, effects of continuous injection rate ramp-down (i.e., “inversed-delta” injection rate shaping) on liquid length, lift-off length and soot onset of diesel spray flame are investigated for better understanding of its combustion characteristics. Time-sequence images of the diesel spray flame are acquired in a constant volume combustion vessel CVCC using a novel TAIZAC injector. One-dimensional modeling is performed to discuss the air entrainment and mixture distributions. During the injection period, no systematic trend is observed on the liquid and lift-off length for any injection profiles. Contrarily, the soot onset for the inversed-delta injection progressively recedes towards the nozzle while it appears constant for the conventional “rectangle” injection. After the end-of-injection EOI, the fuel vaporization and combustion recession occur at a faster rate in the rectangle injection proportional to its injection pressure, possibly due to stronger and faster entrainment waves than that of the inversed-delta injection. From 1D simulation, the liquid length and spray equivalence ratio distributions stratified “layer” seems to be continuously shifted upstream during the injection period in the inversed-delta injection. It is interesting to note that the centerline equivalence ratio value of ϕcl=2 correlate well with the soot onset observed experimentally, suggesting that the air entrainment per injected fuel could likely be promoted during injection period in the inversed-delta injection.

Numerical Investigation of Combustion in HCCI Diesel Engine Fuelled with Biodiesel Blends

Homogeneous Charge Compression Ignition (HCCI) is an advanced combustion technology being considered for internal combustion engines due to the potential for high fuel conversion efficiency and extremely low particulate matter (PM) and Nitrogen Oxides (NOx) emissions. In HCCI engines, there is no direct control method for auto ignition time. A common method to indirectly control the ignition timing in HCCI combustion engines is altering engine’s parameters which can affect the combustion. Previous research has indicated that fuel chemistry has a strong impact on HCCI combustion. This work introduces a new predictive multi-zone model for the description of combustion in HCCI engines. A multi zone model with reduced fuel chemistry was developed to simulate the combustion process in HCCI engines and predict engine performance. In this work, a parametric study on Diesel/Biodiesel blends(D80B20) HCCI combustion is conducted in order to identify the effect of equivalence ratio values (0.1786, 0.27, 0.37, and 0.4762) on combustion and engine performance parameters. Two kinds of parameters will be discussed. First, in-cylinder pressure, temperature and net heat release rate diagrams at altering Diesel/Biodiesel dose (0%, 20%, 40%, 60%), then the second category, the variation of start of combustion and combustion duration which are performance parameters of HCCI Diesel Engine.

The unsteady investigation of methane-air premixed counterflow flame into newly proposed plus-shaped channel over palladium catalyst

In this paper, the time dependent study of methane-air premixed counterflow flame into a newly proposed plus-shaped channel, in order to obtain effects of palladium catalyst surfaces on the flame structure and pollutant emissions, is described. The results are presented at non-catalytic and catalytic conditions with considering effects of reaction time and various equivalence ratios, from lean to rich combustion, on flame characteristics and pollutant emissions. The governing equations are composed of continuity, momentum, energy and mass fraction equations are numerically solved considering a coupled Piso scheme and Simple algorithm. The comparison between the presented model and published data shows an acceptable agreement that confirms the accuracy of this solution. The average values of CH4 mass fraction over the geometry at the presence of palladium catalyst is nearly decreased 25% relative to non-catalytic case. The existence of Palladium catalyst has great impact, mostly 34% decrease, on CO formation but the catalyst leads to increment of CO2 formation 5%. At different values of equivalence ratio, the average temperature of non-catalytic flame is about 16% lower than catalytic one.

Particle-scale modeling of biomass gasification in the three-dimensional bubbling fluidized bed

Biomass gasification in a three-dimensional bubbling fluidized bed is numerically simulated via the computational fluid dynamics coupled with the discrete element method (CFD-DEM) incorporated with heat and mass transfer, and chemical reactions. The particle-scale investigation of the heterogeneous reaction rate of the biomass particles along with the essential aspects (including fluid force, collision force, dispersion) of the solid phase is presented. The results indicate that biomass particles behave with larger horizontal and vertical distance especially in the freeboard region than the sand particles. Strong backmixing of the solid material exists near the sidewall, and large fluid force on the particles appears in the lower bed. Similar trends of the particle-scale fluid force, velocity and dispersion can be observed for the biomass and sand particles, though the magnitudes are larger for the biomass. Chemical reactions result in the axial segregation of the biomass particles. Among all the heterogeneous chemical reactions, the char oxidation is fastest while the hydrogenating reaction is the slowest. Increasing the temperature, and steam-to-biomass ratio and equivalence ratio values all enhance the particle-scale behaviors of both the biomass and sand particles. Also, the temperature improves nearly all the reaction rates. The results obtained here provide essential understanding regarding the particle-scale behaviors of the biomass gasification process in the fluidized bed.