Biomass In Fluidized Bed Reactor Research Articles

Experimental investigation of aerodynamic behavior of wood chips in fluidized bed reactors as a sustainable biomass fuel

Sustainable energy solutions are necessary in the current manufacturing advancements, where a need is being pressed upon biomaterial-based processes. This study examines the aerodynamics of wood chip biomass in fluidized-bed reactors, an essential aspect of sustainable biomass fuel technologies. Through experimental investigations, the current methodology determined the minimum fluidization rates for particles of four distinct sizes and compared these with theoretical prediction-based calculations. A novel laboratory setup featuring a Differential Pressure Feedback Exhaust gas recirculation (DPFE) sensor system was developed to measure these processes continuously to advance the enhancements of the precision and reliability of the findings. Key results include the successful adaptation of the Ergun equation for wood chips, herewith accommodating observed deviations in pressure drops within specific fluidization ranges. This adaptation, along with real-time data tracking of air phase changes using a multifunction measuring device, revealed critical insights into turbulence patterns and particle movement. These results and findings are consistent with theoretical models and underscore the potential to optimize wood chip use in fluidized-bed reactors. The study's results also contribute significantly to the field of renewable energy as they offer a validated methodological approach and practical modifications to existing theoretical models.

Experimental microwave-assisted air gasification of biomass in fluidized bed reactor

Microwave-assisted heating is an effective heating method for thermochemical conversion of biomass. In this study, experimental syngas production from microwave-assisted air gasification of biomass in a fluidized bed reactor at different gasification temperatures, equivalence ratios and silicon carbide loads, was studied and reported. The results showed that the highest syngas yield (78.2 wt%), higher heating value (6.3 MJ/Nm3) and cold gas efficiency (81.8 %) were obtained at gasification temperature of 900 °C, equivalence ratio of 0.35 and silicon carbide load of 30 g, and the gasification temperature had significant influence on the syngas production. Microwave-assisted heating showed positive effect on tar reduction, i.e., the tar content at 900 °C (2.1 wt%) in this study was even lower than the tar content (3.2 wt%) from catalytic electrical air gasification of rice husk at 950 °C. Generally, the introduction of microwave-assisted heating showed positive effect on biomass gasification.

Simulation of Reaction Kinetics and Heat Transfer Effects on Product Yields from Fast Pyrolysis of Oil Palm Empty Fruit Bunch Biomass in Fluidized Bed Reactor

The present work aims to optimize the operating conditions for biofuel production from fast pyrolysis of oil palm empty fruit bunch (OPEFB) biomass in a fluidized bed reactor. The coupled model of global reaction kinetics and heat transfer was applied to investigate the effects of operating conditions (reaction temperature in the range of 748–798 K, vapor residence time in the range of 0.5–2 s, and particle size in the range of 150–500 μm) on the yields of products (liquid (bio-oil), gas, and char) and particle heat transfer of the OPEFB biomass fast pyrolysis. The simulation results of the present model validated the reported experimental data of the product yields of OPEFB biomass fast pyrolysis. The results showed that the maximum yield of high-quality liquid product was obtained at a vapor residence time of 1 s and a reaction temperature of 773 K. Moreover, the OPEFB particle size in the range of 300–350 μm gave the highest yield of liquid product and the good heat transfer of particles. The optimum operating conditions from the simulation of the coupled model can be utilized for the experimental work of fast pyrolysis for different kinds of biomass in a fluidized bed reactor.

Development of Biomass Gasification Technology with Fluidized-Bed Reactors for Enhancing Hydrogen Generation: Part I, Hydrodynamic Characterization of Dual Fluidized-Bed Gasifiers

Various means for enhancing hydrogen content in the syngas from gasification of solid biomass in fluidized-bed reactors were investigated in this study. Steam or oxygen-rich gas can be supplied as gasification medium, to improve the syngas characteristics. Alternatively, a so-called “indirect gasification technology” realizes the thermo-chemical conversion processes in dual reactors, respectively, for combustion and gasification, where gaseous streams in between are separated while solid materials are circulated through. Hence, with air as oxidant for combustion this system features the advantage of producing nearly nitrogen-free syngas. Baseline experiments were firstly carried out to identify performance features; then, parametric studies were conducted and positive trends for enhancing hydrogen generation via biomass gasification were revealed. Moreover, hydrodynamic characteristics in dual reactors were comprehensively envisaged in the cold-flow models to facilitate subsequent investigation into thermo-chemical processes. The experimental results indicated that the circulation mass of the bed material driven by the operating air exceeded the design value, which gave a comfortable safety factor of the engineering design. In addition, the average pressure distribution measured by the cyclic operation of the system was similar to that of the published literature. Based on the experimental results of the cold model, the suggestions of the operating tests in the hot model were addressed. Further efforts will be pursued to establish databases for clean energy and carbon abatement technologies.

Insights into Preventing Fluidized Bed Material Agglomeration in Fast Pyrolysis of Acid-Leached Pine Wood

Acid leaching of lignocellulosic biomass prior to fast pyrolysis can increase the bio-oil yield and improve bio-oil quality. However, fast pyrolysis of acid-leached biomass in fluidized bed reactor...

An R&D Strategy to Decouple Energy from Water

Dr. Addison K. Stark currently serves as a Fellow at ARPA-E, where he has served as Acting Program Director of the ARID program. Prior to joining ARPA-E, Addison completed his PhD at MIT doing fundamental research to elucidate the role of transport phenomena in the thermochemical conversion of biomass in fluidized bed reactors. His research interests include chemical conversion technologies, process intensification of chemical and thermal processes, and leveraging advanced manufacturing technologies for novel reactor designs. Professor James F. Klausner is currently an MSU Foundation Professor and Chair of the Mechanical Engineering Department at Michigan State University. Prior to joining MSU, James was an Ebaugh Professor at the University of Florida and also served three years as a Program Director at ARPA-E where he developed the ARID program. His research focuses on thermal, chemical, and fluid transport in a variety of applications, including energy, processing, thermal management, desalination, powder flow, cryogenics, and bioenegineering.

A two dimensional Euler-Lagrangian model of wood gasification in a charcoal bed — Part III: Parameter influence and comparison

The efficient utilization of biomass in fluidized bed reactors depends on numerous operation conditions and parameters which can be investigated systematically with computational models. Based on a previous study [1] we compare a base scenario which mimics the experimental situation with different parameter settings for an Euler-Lagrangian simulation of wood gasification in a fluidized charcoal bed. For the varied parameters superficial velocity, reactor wall temperature, air inlet temperature, wood particle size, and the wood inlet temperature we analyse the simulation results based on data for temporal evolution of reactor outlet temperature, averaged particle temperature, overall wood mass, overall charcoal mass, concentrations of several gaseous species (N2, CO, CO2, H2, H2O, CH4, C2H2, and three virtual tar components) and axial barycenter data of particles bed mass. Furthermore we show time averaged data for gaseous species and gas phase temperature at the reactor outlet. At the end we critically examine our findings under consideration of the models opportunities and limitations.

전산유체역학(CFD)을 이용한 유동층반응기 내부의 목질계 바이오매스 급속 열분해 모델 비교 및 검증

유동층반응기에서 바이오매스 급속 열분해의 모델화를 통해 열분해로부터 발생되는 바이오오일(Bio-oil) 및 비응축 가스(Non-condensable gas) 성분의 예측과, 이를 통한 수율 향상을 목표로 한다. 본 연구의 목적은 유동층반응기 내부에 투입된 바이오매스가 급속 열분해되는 동안 발생되는 생성물의 수율 예측과 실험 및 시뮬레이션 값을 비교 및 분석하는 것이다. 급속 열분해의 시뮬레이션을 위해 전산유체역학(Computational Fluid Dynamics, CFD) 프로그램이 사용되었으며, 바이오매스의 급속 열분해의 시뮬레이션을 위해 바이오매스 하위 구성 성분의 상세한 열분해 반응 경로가 적용되었다. 이 열분해 반응은 세부적으로 셀룰로오스(Cellulose), 헤미셀룰로오스(Hemicellulose) 및 리그닌(Lignin)의 반응을 포함하고 있으며, 열분해로부터 발생되는 주요 가스 성분은 이산화탄소(<TEX>$CO_2$</TEX>), 일산화탄소(CO), 메탄(<TEX>$CH_4$</TEX>), 수소(<TEX>$H_2$</TEX>), 에틸렌(<TEX>$C_2H_4$</TEX>)이다. 본 모델의 예측치와 기존 문헌(Mellin et al., 2014)의 실험 및 시뮬레이션 결과를 비교하였으며, 그 결과, <TEX>$CH_4$</TEX>, <TEX>$H_2$</TEX> 및 <TEX>$C_2H_4$</TEX>의 경우, 각각 3.7%p, 4.6%p 및 3.9%p로 비교적 일치하게 예측되었지만, <TEX>$CO_2$</TEX> 및 CO의 경우, 각각 9.6%p 및 6.7%p로 높게 예측되었다. 이러한 차이가 발생하는 이유는 이차 열분해 반응에서의 세부 반응조건에 해당되는 각각의 인자의 부재에 기인한 것으로 판단된다. 연구 결과, 시뮬레이션을 통한 모델화 접근이 가능한 것으로 판단되며, 추후에 연구된 모델화를 통해 바이오오일 및 기타 성분들의 예측도 가능할 것으로 판단된다. The modeling for fast pyrolysis of biomass in fluidized bed reactor has been developed for accurate prediction of bio-oil and gas products and for yield improvement. The purpose of this study is to analyze and to compare the CFD(Computational Fluid Dynamics) simulation results with the experimental data from the CFD simulation results with the experimental data from the reference(Mellin et al., 2014) for gas products generated during fast pyrolysis of biomass in fluidized bed reactor. CFD(ANSYS FLUENT v.15.0) was used for the simulation. Complex pyrolysis reaction scheme of biomass subcomponents was applied for the simulation of pyrolysis reaction. This pyrolysis reaction scheme was included reaction of cellulose, hemicellulose, lignin in detail, gas products obtained from pyrolysis were mainly <TEX>$CO_2$</TEX>, CO, <TEX>$CH_4$</TEX>, <TEX>$H_2$</TEX>, <TEX>$C_2H_4$</TEX>. The deviation between the simulation results from this study and experimental data from the reference was calculated about 3.7%p, 4.6%p, 3.9%p for <TEX>$CH_4$</TEX>, <TEX>$H_2$</TEX>, <TEX>$C_2H_4$</TEX> respectively, whereas 9.6%p and 6.7%p for <TEX>$CO_2$</TEX> and CO which are relatively high. Through this study, it is possible to predict gas products accurately by using CFD simulation approach. Moreover, this modeling approach should be developed to predict fluidized bed reactor performance and other gas product yields.

Prediction of the combustion process in fluidized bed based on physical–chemical properties of biomass particles and their hydrodynamic behaviors

The utilization of biomass in fluidized bed reactors is due to alternatives created by the carbon credit market and to environmental concerns. This fact calls for an accurate determination of physical–chemical properties and hydrodynamic studies on biomass-inert binary mixtures. In bubbling fluidized bed combustion processes, the inert material mass is approximately 95% of the total mass of the bed material, and an effective mixture between biomass and inert particles is desired to improve the efficiency of the process. In this study, binary mixtures, composed of biomass and sand as an inert material, were used. Thermal and physical–chemical properties of five biomass samples (sugarcane bagasse, pine sawdust, coffee husk, Tucumã seed, and rice husk) were experimentally evaluated. The morphology of the samples was determined by SEM, and the thermal properties were found by thermogravimetric analysis (TG) and differential thermal analysis (DTA). The hydrodynamic study was carried out in a fluidized bed at room temperature and local atmospheric pressure, in which the minimum fluidization velocity and voidage of the biomass-inert binary mixture were evaluated. The arrangement of the physical–chemical characteristics of biomass and the hydrodynamics of the binary mixture are equally important for predictions of the biomass behavior in fluidized bed combustors.

CFD modelling of the fast pyrolysis of biomass in fluidised bed reactors: Modelling the impact of biomass shrinkage

The fluid–particle interaction and the impact of shrinkage on pyrolysis of biomass inside a 150 g/h fluidised bed reactor is modelled. Two 500 View the MathML sourcem in diameter biomass particles are injected into the fluidised bed with different shrinkage conditions. The two different conditions consist of (1) shrinkage equal to the volume left by the solid devolatilization, and (2) shrinkage parameters equal to approximately half of particle volume. The effect of shrinkage is analysed in terms of heat and momentum transfer as well as product yields, pyrolysis time and particle size considering spherical geometries. The Eulerian approach is used to model the bubbling behaviour of the sand, which is treated as a continuum. Heat transfer from the bubbling bed to the discrete biomass particle, as well as biomass reaction kinetics are modelled according to the literature. The particle motion inside the reactor is computed using drag laws, dependent on the local volume fraction of each phase. FLUENT 6.2 has been used as the modelling framework of the simulations with the whole pyrolysis model incorporated in the form of user defined function (UDF).

CFD modelling of the fast pyrolysis of biomass in fluidised bed reactors. Part B: Heat, momentum and mass transport in bubbling fluidised beds

The fluid–particle interaction inside a 150 g/h fluidised bed reactor is modelled. The biomass particle is injected into the fluidised bed and the heat, momentum and mass transport from the fluidising gas and fluidised sand is modelled. The Eulerian approach is used to model the bubbling behaviour of the sand, which is treated as a continuum. Heat transfer from the bubbling bed to the discrete biomass particle, as well as biomass reaction kinetics are modelled according to the literature. The particle motion inside the reactor is computed using drag laws, dependent on the local volume fraction of each phase. FLUENT 6.2 has been used as the modelling framework of the simulations with the whole pyrolysis model incorporated in the form of user-defined function (UDF). The study completes the fast pyrolysis modelling in bubbling fluidised bed reactors.

CFD modelling of the fast pyrolysis of biomass in fluidised bed reactors, Part A: Eulerian computation of momentum transport in bubbling fluidised beds

The fluid–particle interaction inside a 150 g/h fluidised bed reactor is modelled. The biomass particle is injected into the fluidised bed and the momentum transport from the fluidising gas and fluidised sand is modelled. The Eulerian approach is used to model the bubbling behaviour of the sand, which is treated as a continuum. The particle motion inside the reactor is computed using drag laws, dependent on the local volume fraction of each phase, according to the literature. FLUENT 6.2 has been used as the modelling framework of the simulations with a completely revised drag model, in the form of user defined function (UDF), to calculate the forces exerted on the particle as well as its velocity components. 2-D and 3-D simulations are tested and compared. The study is the first part of a complete pyrolysis model in fluidised bed reactors.

Biomass-derived hydrogen from an air-blown gasifier

The goal of this research is to produce high concentrations of hydrogen from gasification of biomass. Air-blown gasification of biomass in fluidized bed reactors produces relatively low concentrations of hydrogen (about 8 vol.%). Steam reforming of tars and light hydrocarbons and reacting steam with carbon monoxide via the water–gas shift reaction can increase hydrogen content in the producer gas to almost 30 vol.%. In these experiments, the temperature, space velocity, and steam/gas ratio were varied to determine the effect of these variables on hydrogen production. Characterization of the catalysts by X-ray photoelectron spectroscopy (XPS) and BET analysis was also performed. These analyses showed that coke and small quantities of sulfur and chlorine deposited on the catalysts, although catalytic deactivation was not evident during the tests.