Circulating Fluidized Bed Furnace Research Articles

Mechanical properties and microstructural discrepancies of concrete with flotation-modified fly ash from circulating fluidized bed and pulverized coal furnaces

Fly ash (FA) is a by-product of coal-fired power generation in thermal power plants. Disparities in coal types and combustion furnaces result in varying levels of unburned carbon in FA, hindering its effective utilization. In this study, FA from a circulating fluidized bed furnace (CFBFA) and pulverized coal furnace (PCFFA) was modified using froth flotation technology, and the influence of the modified FA from the froth flotation process on the mechanical properties and microstructural discrepancy of concrete was analyzed through the preparation of mortar and cement paste specimens. The results indicated that the flotation process proved effective in reducing the unburned carbon content in FA, with modified PCFFA showing higher surface area and fluidity, opposite to CFBFA. Notably, the flotation process altered CFBFA's mineral content, reducing CaSO4·2 H2O from 26.6% to 7.5% and increasing CaSO4, enhancing hydration and strength in concrete applications. The optimal FA dosage was found to be 20%, with CFBFA specimens displaying superior compressive strength across all tests. Conversely, the modified PCFFA exhibited low activity, making it challenging to reach the desired strength after 28-d. This study serves as a theoretical foundation for the application of highly unburned carbon FA in construction engineering and promotes the circular development of FA resources.

CFD Simulation of Biomass Combustion in an Industrial Circulating Fluidized Bed Furnace

ABSTRACT In this study, a three-dimensional computational fluid dynamics (CFD) model is employed to investigate the hydrodynamic and combustion characteristics of biomass particles in an industrial-scale circulating fluidized bed (CFB) furnace. The CFD model considered here is based on the Eulerian-Lagrangian framework, the multi-phase particle-in-cell (MP-PIC) collision model, the coarse grain method (CGM), and a recently developed distribution kernel method (DKM). The challenge of simulating industrial-scale CFB furnaces using CFD lies in the large number of particles in the system. MP-PIC and CGM showed that local particle overloading could occur, causing the numerical simulation to diverge. The combination of MP-PIC with CGM and DKM was shown to overcome this problem. The CFD predictions werecompared with onsite temperature experiments in the furnace, and the predicted furnace temperature agreed fairly well with the measured data. Using the CFD results, the study analyzed the transient solids mixing and fluidization characteristics, as well as the thermochemical process in biomass combustion. The simulated individual particle provided insight into the physical and chemical processes of the granular flow in the dilute/dense regions of the CFB furnace. The simulated results revealed the CO and NOx emission processes in the furnace.

Experimental study on the effect of limestone on SO2 and NO emission characteristics during coal/coke combustion

Adding limestone to coal combustion reduces SO2 emissions but sometimes increases NO emissions, posing a challenge for synergistic SO2 and NO control in circulating fluidized bed (CFB) boilers. Limestone in the CFB furnace can participate in the conversion of sulfur and nitrogen compounds from coal and its devolatilized coke. This study compared the effects of limestone on SO2 and NO emission characteristics during coal/coke combustion to explore the potential for controlling both emissions. Combustion experiments were conducted in a fixed-bed reactor under different reaction parameters including Ca/S mole ratio, oxygen concentration, and temperature. Results showed that SO2 emissions decreased and NO emissions increased with increasing Ca/S mole ratio for both fuels. Comparing the emissions from fuels with and without limestone addition, a lower oxygen concentration decreased the desulfurization efficiency and the increment of NO emissions caused by limestone for both fuels. Temperature had opposite effects of limestone on coal or coke combustion. For coke, higher temperatures improved desulfurization efficiency and decreased the increment of NO emissions caused by limestone. For coal, the effects were reversed. To explain the impact of temperature, the sulfur and nitrogen migration paths affected by limestone were analyzed based on the XPS results of the fuels. Thiophene-S and N-Q became the main sulfur and nitrogen components in coke at high temperatures. The conversion of thiophene-S into SO2 is slow, and the limestone is calcined more fully during coke combustion, improving the utilization rate of limestone. N-Q tends to be converted into NH3. Further, NO is reduced by NH3 over the catalyze of CaO at low oxygen conditions. This reaction process decreases the increment of NO emissions caused by limestone.

Variations in the physicochemical properties of spent honeycomb V2O5-WO3/TiO2 catalysts from PC and CFB boilers SCR denitration systems

The massive production of spent honeycomb V2O5-WO3/TiO2 catalysts has caused serious environmental hazards. Revealing the physicochemical property variations of the spent catalysts is of great significance to clarify the deactivation mechanism of catalysts and the recovery of the spent catalysts. This study focused on the changes of typically spent catalysts, selected from pulverized coal (PC) and circulating fluidized bed (CFB) boiler deNOx systems, morphologies, pore structure, chemical composition, carrier, and active components properties, etc. The activities of most spent catalysts could be to more than 95% at 300–400 °C after vibration cleaning. The pore blockage caused by fly ash and sulfur deposition is the major deactivation factor of the catalysts from the two furnace systems. The catalysts from CFB furnaces are more easily deactivated, which is owing to they are more prone to occur severe pore structure loss. The transformation of anatase to rutile TiO2 as one of the major factors causing the pore structure loss would form the irreversible deactivation of the catalysts. The valence state of the active component V has shifted. The spent catalysts from PC systems typically exhibit higher V4+/Vn+ ratios. However, those from CFB systems display a noticeable decrease, which may be attributed to the formation of CaWO4, resulting in the destruction of dispersed active sites on the surface. Finally, the deactivation mechanism of the spent catalysts from different furnaces of coal-fired power plants was summarized. This research is beneficial for further modification of SCR catalysts under different application conditions and provides valuable insights into the classification and recycling of the spent catalysts.

Prediction and minimization of NOx emission in a circulating fluidized bed combustor: Improvement of bed quality by optimizing cyclone performance and coal particle size

• Improvement of cyclone performance contributes to reducing the NO x emission. • Reducing coal particle size can decrease the NO x emission. • NO x emission may be further reduced by reducing the height of the coal inlet. • Effects of cyclone efficiency and coal size on combustion efficiency are discussed. • A comprehensive CFB mathematical model is applied to further analyze the mechanism. The NO x emission of circulating fluidized bed (CFB) boilers can be evidently reduced via optimization of the cyclone performance and the coal particle size, which has been proved in industrial practices, while there are few reasonable interpretations for these phenomena so far. In this paper, a comprehensive 1-dimensional/1.5-dimensional CFB mathematical model was applied to investigate the effect of these two important factors on NO x emission. Simulation results on two commercial CFB boilers indicate that increasing the cyclone efficiency and reducing the coal particle size can significantly decrease the average size of bed materials and increase the solid suspension density in the freeboard zone; namely, the bed quality is improved. The local gas–solid flow behaviors inside the CFB furnace will be accordingly changed, such as the increasing volume fraction of bubble phase in dense bed, shortening of secondary air penetration depth, enrichment of particles in the downward-flow annulus or clusters, etc. Consequently, the reducing atmosphere will be formed or enhanced in local areas, leading to the effective inhibition of NO x formation. Meanwhile, the increase in the bed inventory of fine char particles also facilitates the reduction of NO x . Moreover, if appropriately reducing the height of the coal inlet or feeding fine coal particles from the solid recycle system, the NO x emission may be further reduced due to the adjustment of the volatiles release pattern. In addition, the reduction of coal particle size can contribute to the increase in fuel combustion efficiency, while the unburned carbon content in fly/bottom ash may increase or decrease with the improvement of cyclone efficiency. This study further analyzes the influence of gas–solid flow characteristics on the chemical reaction process and provides a new solution to the low-cost pollutant emission control for CFB boilers.

Study on economic operating mode for combined desulfurization system of circulating fluidized bed unit

With the stricter emission regulation taking effect, most of circulating fluidized bed (CFB) power generation units operates with conventional desulfurization in CFB furnace and flue gas desulfurization (FGD) technology to meet the requirements of ultralow SO2 emission. Therefore, it is urgent to analyse operating cost of the combined desulfurization system and explore the low-cost operating mode for CFB units. In this paper, the operating cost model of combined desulfurization system was established, in which the influence of desulfurization in furnace on thermal efficiency of the CFB boiler was considered. Then, the operating cost of combined desulfurization system under different load conditions for a 300MW subcritical CFB unit was analysed, combined with measured data. The operating cost optimization result shows that, under different loads, when Ca/S is in the range of 0.4 to 0.5, the operating cost of combined desulfurization system reaches the minimum. In addition, as the unit load increases, the higher proportion of SO2 removal in FGD is required to achieve low-cost operating mode for CFB units.

Operational Flexibility of a CFB Furnace during Fast Load Change—Experimental Measurements and Dynamic Model

The share of power from fluctuating renewable energies such as wind and solar is increasing due to the ongoing climate change. It is therefore essential to use technologies that can compensate for these fluctuations. Experiments at 1 MWth scale were carried out to evaluate the operational flexibility of a circulating fluidized bed (CFB) combustor during transient operation from 60% to 100% load. A typical load following sequence for fluctuating electricity generation/demand was reproduced experimentally by performing 4 load changes. The hydrodynamic condition after a load change depends on if the load change was in positive or negative direction due to the heat stored in the refractory/bed material at high loads and released when the load decreases. A 1.5D-process simulation model was created in the software APROS (Advanced Process Simulation) with the target of showing the specific characteristics of a CFB furnace during load following operation. The model was tuned with experimental data of a steady-state test point and validated with the load cycling tests. The simulation results show the key characteristics of CFB combustion with reasonable accuracy. Detailed experimental data is presented and a core-annulus approach for the modeling of the CFB furnace is used.

Operational Flexibility of a CFB Furnace during Fast Load Change—Experimental Measurements and Dynamic Model

The share of power from fluctuating renewable energies such as wind and solar is increasing due to the ongoing climate change. It is therefore essential to use technologies that can compensate for these fluctuations. Experiments at 1 MWth scale were carried out to evaluate the operational flexibility of a circulating fluidized bed (CFB) combustor during transient operation from 60% to 100% load. A typical load following sequence for fluctuating electricity generation/demand was reproduced experimentally by performing 4 load changes. The hydrodynamic condition after a load change depends on if the load change was in positive or negative direction due to the heat stored in the refractory/bed material at high loads and released when the load decreases. A 1.5D-process simulation model was created in the software APROS (Advanced Process Simulation) with the target of showing the specific characteristics of a CFB furnace during load following operation. The model was tuned with experimental data of a steady-state test point and validated with the load cycling tests. The simulation results show the key characteristics of CFB combustion with reasonable accuracy. Detailed experimental data is presented and a core-annulus approach for the modeling of the CFB furnace is used.

CFD modeling of sodium transformation during high-alkali coal combustion in a large-scale circulating fluidized bed boiler

The ash-related problems of fouling and slagging occur easily during high-alkali coal combustion in boilers. In this study, numerical calculations were performed to investigate the sodium migration mechanism and ash deposition on heating surfaces in a large-scale circulating fluidized bed (CFB) boiler during the burning of high-alkali coal. The calculation principle was based on a comprehensive three-dimensional CFB combustion model and a sodium migration model from our previous study. The computing object of this study was a 300 MW subcritical CFB boiler. By performing a simulation, the distributions of NaCl(g) and Na2SO4(g) along the furnace were displayed. The rates of sodium deposition via condensation, inertial impaction, and thermophoresis on the water walls and suspended panels were analyzed. Additionally, the net deposition rates of fly ash on the water walls and suspended panels were determined. Then, the tendency of fouling and slagging in different areas of the CFB furnace could be predicted and judged. Calculation results for the gas–solid flow, furnace temperature, and gaseous species agreed with the measured data.

Effect of oil shale semi-coke on deposit mineralogy and morphology in the flue path of a CFB burning Zhundong lignite

The effect of oil shale semi-coke (SC) on the mineralogy and morphology of the ash deposited on probes situated in the flue path of a circulating fluidized bed (CFB) which burns Zhundong lignite (ZD) was investigated. 10 wt% or 20 wt% SC was added to ZD, which were then combusted in the CFB furnace at 950°C. Two probes with vertical and horizontal orientations were installed in the flue duct to simulate ash deposition. Both windward and leeward ash deposits on probes (P1W, P1L, P2W and P2L) were analyzed by using a scanning electron microscopy with energy dispersive X-ray (SEM-EDX), X-ray diffraction (XRD), an inductively coupled plasma optical emission spectrometry ICP-OES, and a particle size analyzer. When ZD was burned alone, the P1W deposit was comprised of agglomerates (< 30 µm) enriched in CaSO4 and Na2SiO3, incurring significant sintering. The P1L and P2W deposits, however, were of both discrete and agglomerated particles in similar mineral phases but with coarser sizes. The P2L deposit was mainly fine ash particles where Na2SiO3 and Na2SO4 were absent. As SC was added, the agglomerates in both P1W and P1L decreased. Moreover, SiO2 and Ca/Na aluminosilicates dominated the mineral phases whereas Na2SiO3 and Na2SO4 disappeared, showing a decrease in deposit stickiness. Likewise, the P2W deposit was found less spread on the probe, decreasing its deposition propensity. Na-bearing minerals turned into (Na, K)(Si3Al)O8 and (Ca, Na)(Si, Al)4O8 in the P2W deposit. Moreover, Na in the deposits decreased from 32 mg/g to less than 15 mg/g as SC presented. The addition of SC would therefore help alleviate the propensity of ash deposition in the flue path in the CFB combustion of ZD.

A note on large-size supercritical CFB technology development

Circulating fluidized bed (CFB) technology has been continuously developing with an increasing number of large-capacity and supercritical CFB boilers being put into operation. This article reviews the current developments in large capacity CFB boilers in China and presents a note on the most recent development trends. It includes discussions on (1) gas-solid hydrodynamics in large-size CFB furnaces, (2) heat transfer on suspended surfaces, (3) combustion atmosphere and emissions, (4) 3-D CFD numerical simulation for large-scale supercritical CFB boilers, (5) integrated energy saving technologies, (6) optimal operation of an integrated desulfurization system, (7) erosion and protection of heat transfer surfaces, (8) problems in operation and their solutions, (9) combustion of coal with high alkali content.

Applications of Ultrafine Limestone Sorbents for the Desulfurization Process in CFB Boilers

With the stringent emission regulation taking effect, it is difficult for the conventional desulfurization technology in circulating fluidized bed (CFB) boilers to meet the requirements of ultralow SO2 emission. Therefore, in this paper, the application of natural ultrafine limestone, with a Sauter mean diameter of less than 20 μm, was tested by conducting bench-scale, pilot-scale, and commercial-scale experiments to realize highly efficient desulfurization in CFB furnaces. In the past, such small-size limestone was considered unsuitable for CFB boilers. However, as demonstrated by bench-scale results, the desulfurization performance was clearly superior to that of coarse limestone, especially at low SO2 concentrations. In a 3 MWth pilot-scale CFB boiler, the ultrafine limestone exhibited competent desulfurization efficiency to that of the coarse limestone but clearly less significant catalytic effects on NOx formation. As revealed by field tests in four commercial-scale CFB boilers, when high-efficiency cyclones were applied to CFB boilers, the mass inventory of ultrafine particles was significantly increased and the residence time would be extended accordingly; thus, the ultrafine limestone can be used to achieve high desulfurization efficiency and even ultralow SO2 emission with a favorable Ca/S ratio. Furthermore, a technical roadmap was drawn for the cost-effective control of SO2 emission.

Investigation into scavenging of sodium and ash deposition characteristics during co-combustion of Zhundong lignite with an oil shale semi-coke of high aluminosilicate in a circulating fluidized bed

Scavenging of sodium and ash deposition characteristics during co-combustion of Zhundong lignite with an oil shale semi-coke in a circulating fluidized bed (CFB) were investigated. Zhundong lignite (ZD) and its blends with the semi-coke (SC) of 10 and 20 wt% were combusted in the CFB furnace at 950 °C. Two air-cooled probes were placed in the furnace chamber (P1) and at the cyclone outlet (P2), respectively, to simulate ash deposition. The bottom ash, fly ash and ash deposits on the probes were collected and analysed by using XRD, SEM-EDX, ICP-OES and laser particle analyser. Results show that the fly ash burning ZD was comprised of sub-micron particles and agglomerates enriched in CaSO4 and SiO2, with Na being NaAlSi3O8, Na2SiO3, Na2Si2O5 and NaAlSiO4. When SC of high Si/Al was added, the fly ash was comprised of sub-micron particles with less agglomerates, where Na-bearing minerals were also evidently reduced. Likewise, the bottom ash was coarse-grained particles rich in SiO2, (Ca,Na)(Si,Al)4O8 and CaSiO3 during ZD combustion but changed to SiO2, (Na,Ca)Al(Si,Al)3O8 or NaAlSi3O8 as SC was added, suggesting that Na was captured by SC and retained in the bottom ash. The deposit on P1 was enriched in Na2SO4 and CaSO4 when ZD was burned but turned into coarse-grained particles rich in Ca/Na aluminosilicates while SC presented, showing a decreased sintering propensity. Likewise, the P2 deposit was of Ca/Na sulphates agglomerates, but became refractory SiO2, Ca sulphate and aluminosilicates as SC added. Ash deposition in CFB burning ZD is consequently mitigated with SC addition.

Application of ultra-low NOx emission control for CFB boilers based on theoretical analysis and industrial practices

Circulating fluidized bed (CFB) boilers face sever challenges in China due to the new ultra-low emission rules, more specifically, the NOx emission must be lower than 50 mg/m3. In this paper, NOx evolution inside CFB furnaces and the gas-solid flow characteristics were reviewed. It is found that NOx emission can be reduced through re-specification of fluidization state, namely, improving the bed quality. A low NOx emission (de-NOx) technology applied to CFB boilers was thus proposed. The keys of the technology are decreasing the average size of bed materials, limestone included, and increasing the solid circulating rate by improving the performance of circulating loop including improving cyclone efficiency, controlling slag discharge, etc. Some industrial practices showed that when the average size of bed inventories is markedly reduced, and when using ultrafine limestone, NOx emission can be significantly decreased without undermining high efficiency desulfurization. This paper provides a new solution to low-cost pollution control of CFB boilers.

Core-annulus model development and simulation of a CFB boiler furnace

Mathematical models of circulating fluidized bed (CFB) combustion systems vary from simple lumped models to full-scale 3D models with multi-phase flow fields. Models help to predict the behavior of the boiler under new operating conditions and to understand the underlying phenomena. Is it more important to make experiments or models? The answer is both. The real values can be assessed with the help of experiments and refined models. Is a complex model always better than a simple one? A simple model can be more easily modified and better adapted to the actual use.A 1,5-dimensional model of a CFB furnace is the simplest possible model that takes into account the most important heat transfer and flow features. Of these solids circulation is the most important factor that determines the amount of heat transfer at the furnace walls. Consequently, regulating the solids circulation is the fundamental means of load control in CFB furnaces. One dimensional model takes into account only the vertical flow direction, but 1,5-dimensional model considers solids circulation inside the furnace as well. The internal circulation is up to 2 times greater than the circulation around the solids separator and return in CFB combustors. 1,5-dimensional model is also called the core-annulus model. The furnace is considered as a cylinder with an annular space around it. The hot solids flow upwards along the cylinder and downwards along the annular space.In this study, a core-annulus model is implemented using a commercial IPSEpro software. The developed model consists of several modules. The mathematical principles of each module is described. The software is also presented briefly. The new model is applied to study the behavior of a large biomass boiler. The model inputs include mass flows of fuel and air, fuel type and parameters regarding the solids amount, size and distribution. In addition to inputs for the design operation, other scenarios are considered such as partial load and burning of different fuels. Strengths and weaknesses of the model are also assessed and pathways of future research are reviewed.

Analysis of the processes in fluidized bed boiler furnaces during load changes

Due to increased share of intermittent renewable energy production, flexibility demands for boiler based energy production have increased in the form of required faster ramp rates and lower allowed minimum loads. To illustrate the effects of changes in boiler load, the present paper focuses on analysis of furnace processes in bubbling fluidized bed (BFB) and circulating fluidized bed (CFB) combustion during a load change. Computational fluid dynamic (CFD) modeling is used as the analysis tool. The paper illustrates by means of simulations what changes take place in the temperature and composition distributions. The effects on emissions are also analyzed in the case of the BFB boiler. The differences between CFB and BFB furnaces in their capability to respond to load change demands are discussed.

Study on the combustion and NOx emission characteristics of low rank coal in a circulating fluidized bed with post‐combustion

The combustion and NOx emission characteristics of low rank coal have been investigated in a circulating fluidized bed test plat, which was composed of a circulating fluidized bed (CFB) and post‐combustion chamber (PCC). The effects of the air stoichiometric ratio in the circulating fluidized bed furnace and air arrangement in the post‐combustion chamber were studied. In the optimized experimental condition, with the air stoichiometric ratio in the CFB (λCFB) at 0.963, and post‐combustion air (PCA) injected into the PCC using ports PCA1 and PCA3, the NOx emission was reduced to 48.7 mg/m3. The conversion of the fuel‐nitrogen in the coal into NOx did not occur under the reducing atmosphere in the circulating fluidized bed furnace. The final quantity of NOx generated from the combustion in the PCC was formed from gaseous HCN and residual nitrogen in fly ash, which flowed with flue gas from the CFB furnace. Enhancing the burnout fraction of coal in the CFB and using the air arrangement in the PCC could effectively reduce the final emission of NOx.

Design of large scale oxy-fuel fluidized bed boilers: Constant thermal power and constant furnace size scenarios

This work investigates the design of large scale oxy-fuel circulating fluidized bed (CFB) boilers in two industrial pathways of constant thermal power scenario and constant furnace size scenario using a new version of a model validated with 100 kWth and 4 MWth oxy-fuel CFB boilers. This work suggests that the major approach for elevating the circulating solids flux is to utilize more efficient cyclones with better efficiency which leads to higher share of fines and nanoparticles in the CFB loop while the amount of aerosols is reduced. Maximum heat flux from furnace walls is 2.4 times and CO peak is 2.2 times in constant furnace size scenario compared to constant thermal power scenario respectively, showing more intense combustion in the prior scenario. Based on the results found in this work, if the industry is to aim to operate the large-scale oxy-fuel CFB boilers at high O2 concentrations, the utilization of the constant thermal power scenario is much safer for the industry compared to constant furnace size scenario. This work shows that the aspect ratio of future large-scale oxy-fuel CFB furnaces are larger than the current air-fired ones leading the oxy-CFB furnace geometry to approach the fluid catalytic cracking fluidized beds.

Numerical Research Of Influence Of Disperse Composition On Characteristics Of Combustion Of Coal-Fired Circulating Fluidized Bed

The peculiarity of mathematical modeling of the circulating fluidized bed (CFB) is that the solid phase (fuel and ash particles) is always a polydispersed medium. The paper constructed a mathematical model of gas dynamics, heat and mass transfer and combustion in the furnace volume of CFB steam generator with a highly concentrated content of the dispersed phase in relation to the investigation of processes in aerothermochemical CFB furnace. Taking into account: the turbulent structure of the two-phase flow, radiation heat transfer in a dusty environment, the chemical reaction kinetics of ignition and combustion, the effects of the power and thermal interactions between the particles and the particles with the wall. A model of such an environment has been chosen phenomenological model of interpenetrating continua Rahmatulina HA. The characteristic features of CFB technology are: firstly organized circulation of solid particles; Second, the repeated return unburned coarse fractions in the fluidised bed. As a result, during the low-temperature burn-in CFB increased almost two orders of magnitude compared with torch mode, allowing you to burn the most difficult fuels in the energy sector. Numerical analysis of data showed that the best results on the effects of polydisperse composition for fuel combustion characteristics in CFB process provides a particle size distribution in which a small fraction predominates.

Three-dimensional modeling of biomass fuel flow in a circulating fluidized bed furnace with an experimentally derived momentum exchange model

In modeling of large-scale circulating fluidized bed (CFB) furnaces, semi-empirical 3D process models are used in furnace analysis, design and optimization as their accuracy versus computational times make them more favorable than high resolution computational fluid dynamics (CFD) in many engineering type of studies. One of the key aspects in determining the furnace performance and efficiency is the correct modeling of the fuel flow as it determines where the thermochemical reactions take place in the furnace, affecting the temperature and gaseous species distributions. In modeling, this requires the suitable approximation of the momentum exchange between the fuel and the gas phase as well as the fuel and the bed material. To model the momentum exchange with current models presented in the literature, information on the material properties, namely the fuel particle size has to be given. The determination of particle size is affected by the particle shape and for irregular, non-spherical material, such as biomass, currently there are no readily applicable methods to determine the effective momentum exchange based on the particle geometry.In this work, a new gas–fuel momentum exchange model is developed for the fuel flow, which acknowledges the effect of physical properties of the fuel, namely the shape and size. Due to impracticality of determining a representative fuel particle size, characterization data is utilized to directly obtain information on the gas–fuel momentum exchange and the particles are classified based on their elutriation behavior, rather than particle size. The new momentum exchange model is utilized with an existing semi-empirical 3D process model and applied in simulation of a utility-scale CFB furnace firing biomass. The simulation results are compared with measurements and are found to be in good agreement, which demonstrates the applicability of the modeling approach. The presented method improves the modeling of fuel flow with CFB process models, especially with irregular, non-spherical fuels such as biomass. The improved modeling of fuel flow within large-scale CFB furnaces enables faster and more reliable design and analysis of CFB furnaces.