Packed Beds Research Articles

Green Clay Materials Applied in Packed Bed Columns for the Hexavalent Chromium Adsorption from Aqueous Solutions

Green Clay Materials Applied in Packed Bed Columns for the Hexavalent Chromium Adsorption from Aqueous Solutions

Modeling selective absorption of H2S from a gas mixture containing CO2 within rotating packed bed based on surface renewal theory

Compared to conventional packed beds (PBs), the rotating packed beds (RPBs) demonstrate superior selectivity for H2S. RPBs can selectively absorbing more than 99 % of H2S in CO2-rich gas mixtures, while the co-absorption rate of CO2 in RPBs is only 1/9 of that in PB columns. Therefore, RPBs have been well applied in the gas purification for natural gas, blast furnace gas, and refinery gas. While, modeling the selective reaction process in RPBs under conditions of rapid liquid film renewal remains challenging. Here, a diffusion–reaction mass transfer model based on surface renewal theory is established. The model elucidates the mechanism behind the selective absorption of H2S, and also demonstrate how RPBs enhance liquid film absorption. Experimental data collected from an RPB operating under actual conditions were used to validate the model. The model demonstrates high precision in predicting the removal efficiency of H2S and CO2.

Gasification of mixed plastic-biomass pellets in an updraft fixed bed reactor: A simplified dynamic model

In the context of materials recycling, updraft gasifiers are promising small and middle-scale reactors to obtain building blocks and/or energy from waste plastic and biomasses. To this aim, these kinds of materials can also be mixed and reduced into pellets, while the needed heat enters the process with a heated carrier gas. In order to preliminarily design a gasifier to check its feasibility with an available feedstock, currently available models are inadequate. Thermodynamic ones are useless for the purposes of sizing, while too detailed rate-based models (e.g. based on fluid-dynamic modelling) are too substrate specific, need detailed input data and are extremely time consuming. A dynamic model of a fixed-bed reactor for biomass gasification is presented here. The gasifier is loaded continuously from the top with solid pellets and fed with counter-current air flow. The model considers: i) a one-step gasification kinetics, yielding a product spectrum which matches experimental data from the literature; ii) dynamic gas and solid energy balances and iii) steady-state energy balance for the furnace. The model has been applied to describe a tubular furnace (Ø 40 cm) which gasifies 500–1000 kg day−1 of mixed wastes using air heated up to 1200 °C: on the basis of the produced chemicals, the energy consumption was estimated as ca. 2 MJ per kg of solid feedstock. This simplified approach proved robust in describing the overall yields and start-up dynamics, showing higher reliability than equilibrium models in addressing the temperature profiles, at the cost of a simplified reaction kinetic and pellet description with respect to more complex simulation models. The model validation was done by comparison between the calculations results and available pilot-plant data. An overall good fit of the data can be concluded. The solid-gas heat transfer and the bed packing are the main computational criticalities to achieve a reliable process description.

Microwave-Assisted Oxidation of N2 into NOx over a La-Ce-Mn-O Perovskite Yielding Plasmas in a Quartz Flow Reactor at Atmospheric Pressure

N2 oxidation to NOx is a challenging reaction, and alternative routes to the industrial Ostwald process are of interest. A perovskite under flowing O2-N2 mixtures at atmospheric pressure in a quartz tube reactor was irradiated by microwaves (MW), leading to the formation of hot spots and plasmas within the catalyst bed. NOx concentrations up to 2.5 vol.% in one pass were obtained at 600 W. Using a lower MW power of 100 W led to a pulsed mode yielding lower NOx concentrations and no noticeable damage to the quartz reactor. The formation of plasma was strongly dependent on the perovskite bed packing. The perovskite acted primarily as a susceptor and likely also as a catalyst, although the proportion of heterogeneous and homogenous reactions could not be determined in the present study. The simple reactor layout allowing operation at atmospheric pressure is promising for the development of practical MW-assisted N2 fixation technologies.

Impact of the Channel- to Particle-Diameter Ratio on the Liquid–Liquid Mass Transfer and Pressure Drop in Micro Packed Bed Reactors

Impact of the Channel- to Particle-Diameter Ratio on the Liquid–Liquid Mass Transfer and Pressure Drop in Micro Packed Bed Reactors

Effect of hydraulic retention time and effluent recycle ratio on biogas production from POME using UASB-HCPB fermentor assisted with ultrafiltration membrane at mesophilic condition

Biogas is renewable energy produced through anaerobic digestion based on palm oil mill effluent. Biogas production is overgrowing and is carried out in various bioreactors, such as the Upflow Anaerobic Sludge Blanket - Hollow Centered Packed Bed fermentor. Even though this process is considered successful in producing biogas, it has not adopted a recycling system. Therefore, the remaining sludge (effluent) after the processing process is generally not reused and is thrown into the environment, which still has the opportunity to produce biogas. The combination of the performance of the the Upflow Anaerobic Sludge Blanket - Hollow Centered Packed Bed fermentor with an ultrafiltration membrane is one of the latest innovations to reduce the volume of effluent wasted through recycling the effluent (retentate) into the feed tank. This research aims to produce biogas from liquid waste from palm oil mills using an Up-flow Anaerobic Sludge Blanket-Hollow Centered Packed Bed fermentor combined with ultrafiltration membranes under mesophilic conditions. In this research examines the effect of hydraulic retention time and the effluent recycling ratio on the pH profile, alkalinity, production, biogas composition, and kinetics of biogas production. The research began with loading up by varying the hydraulic retention time, namely 40, 25, and 10, until reaching the target hydraulic retention time of 6 days in a 5.4 L fermentor with a pH of 7 ± 0.2 under mesophilic conditions. Next, the effect of the recycling ratio was studied by varying the effluent (retentate) recycling ratio, namely 0, 15, and 25 %. The parameters analyzed are pH, M-Alkalinity, total solids, volatile solids, total suspended solids, volatile suspended solids, chemical oxygen demand, volume, and biogas composition. The organic content in the substrate is used as a kinetic parameter for biogas production using the modified Gompertz, Logistic, and Monod kinetic equation. The research results show that in mesophilic conditions, a recycling ratio of 25 % shows better results compared to ratios of 0 and 15 % where biogas production is 20×10-5 L/mgVS.day, with a best composition of methane, carbon dioxide and hydrogen sulfide each of 88.2; 10.8; and 0.07 % (v/v), with ΔVS decomposition at 15 % and 25 % recycle ratio of 42.50 and 45.83 % (w/v). The equation for the biogas production rate constant as a function of temperature obtained is the biogas production rate constant: M=299.81+exp(14.28299.8(0.39−t)+2) for logistic model, M=27.2xs2.46+s for monod model, M=250.1×exp{−exp[1.85.e250.1(0.42−t)+1]} for Gompertz modified kinetic model. Based on the scanning electron microscope results, it can be seen that the membrane used is an ultrafiltration membrane type, with a characteristic thickness of 7-8 µm and a pore size of 100–300 nm. The scanning electron microscope results also show that effluent contaminants deposition in the inner layer (spinger membrane) and deformation of the spinger structure are driven by forces during the effluent recycling process. The results obtained in this research show that this condition provides a clean, effective, and low-energy biogas production system that can be optimistically applied to the national palm oil industry power generation system.

Influence of packing height on the pyrolysis products of Jimsar (China) oil shale

AbstractThe effect of particle packing height (10, 30, 50, 70 mm) on the yield and composition of oil shale pyrolysis products is investigated. The results show that the oil yield could decrease 1.0% and the noncondensable gases yield could increase 0.5% as the oil shale packing height increased from 10 to 70 mm. The main hydrocarbon gases are C1–C6 gases, and the increase of packing bed height could decrease the relative content ratio of alkanes to alkenes in hydrocarbon gases. The primary components of the derived oil are aliphatic compounds, aromatic compounds, and compounds containing heteroatoms in the carbon atoms range of C6–C28. And the hydrogen type of shale oil is mainly composed of methylene groups (about 70%) with longer alkyl chains, and CH3 in aromatics, cycloalkanes, and alkanes. The chemical composition and hydrogen type have certain regularity changes with the changing of packing height, attributing to the effect of temperature gradients between surface and center of packing bed, and the diffusing time of products through the packing bed.

The effect of imbrication on the porosity value of uniform gravel bed

Existing empirical relations used to predict the porosity of gravel beds are mainly derived from laboratory-generated sediment beds with random grain packing. However, such relations could not adequately describe beds with non-random grain arrangements that occur widely in fluvial deposits. In this work, the effect of grain imbrication on gravel-bed porosity has been quantified using beds with variable strengths of imbrication generated by flume experiments. Mono-sized ellipsoids with specific shapes were used in experiments to remove particle size and sorting effects on porosity. Random bed packings were generated by settling of ellipsoids in still water whilst imbricated beds generated under flowing water. Beds were frozen using liquid nitrogen before extraction. A new relatively simple and time-saving workflow was developed to measure the orientation of particles and quantify the degree of grain imbrication in frozen beds from X-ray Computed Tomography images. Beds with the strongest grain fabric display a ca. 0.03 absolute reduction of porosity value on average (8–10% relative reduction) compared to that of random packing for undisturbed beds. Further, results were obtained for beds deposited under still-water conditions subject to disturbance by shaking, to mimic the potential effect of vibrations from currents, waves or other sources in the environment. A reduction in bed porosity of ca. 0.014–0.018 (ca. 5% relative reduction) is observed between beds with the strongest grain fabric and those with random packing that had undergone shaking after deposition. Hence, a significant proportion (> 50%) of the porosity loss observed for imbricated beds may be attributable to tighter packing due to turbulence-related vibrations from the flow. The small decrease in porosity value despite the formation of strong imbrication is considered to be due to the limited improvement in grain organization, as the results show that the flat shape of the ellipsoids and the uniformity of their size promote the formation of a stacking structure under gravity, leading to a similarly highly ordered grain organization in random packings compared to the imbricated packings.Graphical abstract

ENVIRONMENTAL AND ECONOMIC ASSESSMENT OF COMPOST BARN SYSTEM IN MILK PRODUCTION IN BRAZIL

Intensifying animal productivity in specific areas is recommended to reduce or mitigate greenhouse gas emissions associated with these production systems. This study evaluates the environmental and economic impacts of six dairy farm using an intensive Compost Bedding Pack Barns system in Minas Gerais, Brazil. A Life Cycle Assessment grounded in the IPCC 2006 guidelines, was conducted as a valuable tool in environmental management, providing a comprehensive understanding of the environmental costs from feed cultivation to milk distribution. The Life Cycle Assessment results showed an average carbon footprint of 1.48 kg of CO2 eq. per liter of fat- and protein-corrected milk. Alongside this, an economic and financial viability assessment using investment analysis tools indicated that, despite initial investments and high fixed and variable costs, the system presents strong economic results. These findings support the premise that intensifying productive systems can mitigate environmental impacts while ensuring financial profitability, enhancing the sustainability and competitiveness of Brazil's dairy industry.

Theoretical optimization of bed packing arrangement in cascade Dual-Catalyst system with side reactions

The performance of cascade dual-catalyst systems is highly related to the catalysts spatial arrangement within the bed layers. However, optimization tools for the cascade dual-catalyst layer arrangements are still in need of development. In this study, an optimization framework based on genetic algorithms (GA) and artificial neural networks (ANN) is developed for optimization while explore effects of side reaction on optimized arrangement. Further, a new descriptor as known as delta switch (DS) is introduced. Isolated analysis of the effects of the two types of side reactions shows that the solely side reaction on S0 results in a repeated S0-S1-S0 structure, while the introduce of side reactions on S1 disrupts this structural regularity and reduces the optimal length of the bed layer. Based on DS patterns, a simplified cascade dual-catalysts spatial optimization framework (≤3 layers) is employed, achieving ≥ 95 % performance of original GA.

Effects of Pyrolysis Temperature on Biochar Physicochemical and Microbial Properties for H2S Removal from Biogas

Sludge is produced in sewage treatment plants and is still a problematic waste type after anaerobic digestion. A sustainable sludge management strategy would be to pyrolyze it and obtain biochar suitable for use in biofilters. This article examines the physical and chemical properties of biochar obtained by pyrolyzing sewage sludge at a temperature of 300–600 °C. The pyrolyzed sludge was used in the biofilter as a filler. The results demonstrated biochar packing materials after pyrolysis at 300 °C, 400 °C, 500 °C, and 600 °C, which exhibited porosities of 35%, 42%, 67%, and 75%, respectively. During the research study, it was established that the biofilter showed excellent efficiency (between 55 and 99 percent) when using carbon pyrolyzed at temperatures of 500 °C and 600 °C. In this study, the average growth rates of the number of sulfur-oxidizing microorganisms were 1.55 × 104 CFU/g at the first stage of the biofilter, 2.63 × 104 CFU/g at the second stage, 3.65 × 104 CFU/g at the third stage, 5.73 × 104 CFU/g at the fourth stage, and 2.62 × 104 CFU/g at the fifth stage. The number of sulfur-oxidizing microorganisms in the packing bed of biofilters during the 60-day period of the experiment constantly increased. The experimental results of H2S purification in biogas were compared with mathematical modeling results. These comparative results revealed a consistent trend: the model-estimated filter efficiency also reached 70–90 percent after 60 days of investigation.

Relationship between facility type and bulk tank milk bacteriology, udder health, udder hygiene, and milk production on Vermont organic dairy farms

The primary objective of this cross-sectional observational study was to determine whether bulk tank milk quality, udder health, udder hygiene and milk production outcomes were associated with facility type on organic dairies. A secondary objective was to identify other management-related risk factors associated with bulk tank milk quality, udder health, udder hygiene, and milk production on organic dairy herds in Vermont. We aimed to enroll 40 farms, to compare herds using the 2 most common systems (freestalls, tiestalls) for housing organic dairy cattle in the state with those using a bedded pack during the non-grazing season (typically November-May). Two general styles of bedded packs were observed: cultivated bedded packs and untilled deep bedded packs. Due to the limited number of herds using bedded packs to house lactating dairy cattle in Vermont, we combined untilled and cultivated bedded packs to describe udder hygiene, milk quality, and udder health on these loose-housing systems deeply-bedded with organic material. The study was completed on 21 farms (5 bedded packs, 6 freestalls, 10 tiestalls) before interruption due to the COVID-19 pandemic. Data captured from Dairy Herd Improvement Association records from the test closest to the date of the farm visit included average somatic cell score (SCS), standardized 150-d milk (pounds), % cows with current high SCS (SCS ≥ 4.0), % cows with newly elevated SCS (previous SCS < 4.0 to current ≥ 4.0), and % cows with chronically elevated SCS (SCS ≥ 4.0 last 2 tests). Multivariable linear regression models were used to describe outcomes by facility type, but suffered from limited statistical power due to small group sample sizes. Unconditional comparisons failed to find statistically significant differences between farms grouped by facility type in metrics captured from Dairy Herd Improvement Association test data, bulk tank milk somatic cell count (BTSCC) and aerobic culture data, or udder hygiene scores. A secondary analysis was conducted using univariate linear regression to identify associations between herd management factors and outcomes for all 21 farms combined. Although not all differences found were statistically significant in this secondary analysis combining all farms, numeric differences that may be biologically important are reported showing farms with deeper bedding had a lower BTSCC, lower newly elevated SCS, lower chronically elevated SCS, lower elevated current SCS, lower average SCS, and better udder hygiene metrics. Farms with lower mean udder hygiene scores had numerically lower chronically elevated SCS, lower elevated current SCS, and lower average SCS. We could not reject the null hypothesis that milk quality and udder health outcomes did not differ by facility type, and this does not preclude the existence of biological differences in these outcomes between facility types. The current study provides insight on factors affecting bulk tank milk quality, udder health and hygiene measures on organic dairy farms in Vermont. Bedded packs may be a viable option for confinement housing during the winter non-grazing season for pasture-based herds interested in a loose-housing system in the Northeastern US, but more research such as longitudinal studies with a larger sample size is needed to test this hypothesis.

3D-printed devices for continuous-flow lithium recovery of brines

Adsorption processes were widely used in the recovery of lithium from salt lakes. Fixed-bed continuous flow reactors were mainly used in adsorption due to their simple structure and stable reaction. 3D printing, due to its ability to greatly reduce the packing and fixed-bed reactor design cycle and cost, was gradually becoming as one of the key technologies for intelligent manufacturing of fixed beds. This work utilizes the advantages of digital preparation by 3D printing to address the low elution efficiency and adsorption capacity of titanium-based lithium-ion sieves (Ti-LIS) in fixed-bed lithium recovery. 3D printed fixed bed packing with high adsorption capacity were prepared using an in-situ growth strategy, acidic gel and reactor design were utilized to achieve efficient elution of Ti-LIS. The dynamic adsorption showed that the adsorption capacity of 3D printed fixed bed packing could reach 16 mg·g−1 and the elution efficiency can be increased from 78 % to 95 % with the same amount of acid.

Experimental Investigation of Liquid Holdup in a Co-Current Gas–Liquid Upflow Moving Packed Bed Reactor with Porous Catalyst Using Gamma-Ray Densitometry

This study explores the dynamics of liquid holdup in a lab-scale co-current two-phase upflow moving packed bed reactor, specifically examining how superficial gas velocity influences the line average external liquid holdup at a fixed superficial liquid velocity. Utilizing gamma-ray densitometry (GRD) for precise measurements, this research extends to determining line average internal porosity within catalyst particles. Conducted with an air–water system within a bed packed with 3 mm porous particles, the study presents a novel methodology using Beer–Lambert’s law to calculate liquid, gas, and solid holdups and catalyst porosity that is equivalent to the internal liquid holdup that fills the catalyst pores. Findings reveal a decrease in liquid holdup corresponding with increased superficial gas velocity across axial and radial locations, with a notable transition from bubbly to pulse flow regime at a critical velocity of 3.8 cm/sec. Additionally, the lower sections of the packed bed exhibited higher external liquid holdup compared to the middle sections at varied gas velocities. The liquid holdup distribution appeared uniform at lower flow rates, whereas higher flow rates favored the middle sections.

Design and fabrication of UASB-HCPB reactor assisted UF membrane for POME treatment to produce biogas

Anaerobic process is one of the biological wastewater treatment to produce biogas as renewable energy. Sludge is produced as the main characteristic of UASB (Up-flow Anaerobic Sludge Blanket) which distinguishes it from other anaerobic technologies to produce biogas. A new design of UASB-HCPB (Up-flow Anaerobic Sludge Blanket - Hollow Centered Packed Bed) is used to overcome operational problems in UASB. This research has designed, manufactured, and installed a UASB-HCPB bioreactor with a heating system. UASB-HCPB was designed and fabricated with acrylic material and caldnes used for HCPB. The bioreactor was filled with water to determine the working volume of the bioreactor. The peristaltic pump as the process pump was calibrated; the liquid volume was measured for a certain time span. The jacket heating system was simultaneously controlled with a controller to obtain the temperature of the bioreactor. The working volume of the bioreactor was 5.49 liters. A further modification of the POME treatment is the use of membranes. The membrane used is the cross flow membrane type. The combination of anaerobic bioreactor and the use of membrane can separate the solid biomass from the digester suspension and recycle it to the digester. In this study, biogas production with fresh POME will be carried out using a UASB-HCPB reactor with a combination of ultrafiltration membranes under mesophilic conditions.

Continuous Phenol Biodegradation in a Bioreactor at Upflow Packed Bed by Mixed Microbial Culture

Continuous Phenol Biodegradation in a Bioreactor at Upflow Packed Bed by Mixed Microbial Culture

Operando Nuclear Magnetic Resonance (NMR) Studies of a Trickle-bed Reactor Using D-T2 Correlations.

Catalytic conversions in fine-chemical and pharmaceutical production are increasingly performed in trickle-bed rectors. Optimisation of these processes is usually based on end of pipe measurement made at specific residence times. This process is both time-consuming and the data sometimes challenging to interpret. In the present work, operando nuclear magnetic resonance (NMR) techniques both at the scale of the whole bed (global) and spatially resolved within the bed (local) are used to gain new insights into the catalytic conversion process under reaction conditions. Spatially resolved spectroscopic and diffusion-T2-relaxation (D-T2) methods interrogate local differences in chemical conversion and selectivity, and mass transport (molecular self-diffusion) respectively, thereby providing valuable information for process simulation models. This capability is demonstrated using the continuous flow three phase (gas-liquid-solid) hydrogenation of benzonitrile over a fixed bed of 0.5 wt% Pd/Al2O3 catalyst pellets yielding toluene and benzylamine. Global 1H spectroscopic and D-T2 were used to monitor chemical conversion and the approach to steady state; these were subsequently followed by spatially resolved 1H spectra and spatially resolved D-T2 correlations to examine the local differences in axial conversion and selectivity of the catalyst bed packing. At steady-state a global conversion of 63% was achieved with 65% and 25% selectivity to benzylamine and toluene respectively. Heterogeneities in the local (axial) conversion and selectivity differed by 31% along the total catalyst bed length. These techniques should be applicable to many three-phase heterogeneous catalytic systems provided that the T2 relaxation time of the reactants and products is not prohibitively small.

Effects of location of nano-enhanced PCM-packed bed on the process of heat transfer and phase transition in a nonuniform magnetic field

The phase change and thermal process intensification under nonuniform magnetic field (MGF) effects during hybrid nanofluid (NF) convection are investigated in this study using various arrangements of phase change material (PCM)-packed bed (PB) in a vented cavity. The PCM-PB is is considered as a triangular shape. The numerical research is done using the finite element method for different Reynolds numbers (Re between 200 and 600), inlet port sizes (between 0.5 and 2.5), Hartmann numbers (Ha between 0 and 60), nonuniform MGF component amplitudes (between 0 and 1), and different locations of the triangle PCM-PB zone. The process of phase change is accelerated by increasing the Re and port size, and the entire transition time (tf ) is reduced by 63% and 76%, respectively, when mix/max Re and min/max port sizes are considered. By using NF, the phase change is improved even further, and tf is further reduced by 17.6%–31.5%. When MGF strength and amplitude of the nonuniform component are increased, tf is reduced by about 13% and 6%. At the highest Ha, the average heat transfer (HT) drops by about 59%. The flow patterns, phase transition, and thermal performance are all significantly impacted by the placement of the PCM-PB zone. In terms of phase change process, configuration C2 by using NF at Ha = 60 is the best case while case at Ha = 0 by using only water is the worst case. The tf value is reduced by about 82.6% at the best case. When phase change and HT processes are considered, the optimal design of triangular PCM-PB zones alters.

The effect of biological methods for MSW treatment on the physicochemical, microbiological and phytotoxic properties of used biofilter bed media

Biofilters are commonly used in municipal solid waste treatment (MSW) facilities to remove odors and pollutants from process gases. However, the effectiveness of biofilter bed media decreases over time, necessitating periodic replacement. The type of the treatment process may affect the lifespan of the bed and the way it should be utilized after replacement. This study aimed to analyze the physical, chemical, calorific, microbiological, and phytotoxic parameters of bed media in biofilters operated at an industrial scale in MSW treatment plants. The experiments included three full cycles of biofiltering gases from biodrying, composting, and aerobic biostabilization in two variations. Physicochemical properties (moisture, organic matter, carbon, nitrogen, sulfur, heavy metal contents), respiration activity (AT4), phytotoxicity, and microorganism abundance were determined for initial materials and samples from two biofilter layers collected after each cycle. Results revealed a substantial reduction in AT4 (by 63%-87% compared to initial material), significant moisture content increase in the bottom layers (by 61% or more, depending on the process), and a considerable decrease in microorganism abundance. Biofilter bed media from biodrying and composting exhibited low environmental risk (low heavy metal concentrations, negligible phytotoxicity, and microbiological stability). However, bed packings from aerobic biostabilization processes showed significant inhibition of indicator plants and incomplete sanitization (presence of pathogens like E. coli and Salmonella spp.). Therefore, these bed packings can be utilized for energy recovery, such as incineration after drying. This research provides significant insights into the effectiveness and safety of biofilter bed media in MSW treatment plants.

CHARACTERISTICS OF FLOW REGIMES IN SPIRAL PACKED BEDS WITH SPHERES

Packed beds are used in many fields such as heat exchangers, cooling systems, filtration, and reactors. Porous media can be used in order to enhance the heat transfer between the solid and the fluid, but it also creates higher pressure drops for the same flow rate. The flow regime significantly affects the heat transfer and pumping power of the fluid. It is known that when the channel is either curved or packed separately, the pressure drop increases. There are many studies on pressure drop and flow regimes in porous media or curvilinear channels. However, there are not many studies on pressure drop and flow regimes in a curvilinear packed bed. In this work, the pressure drops and flow regimes were determined when the channel is both curved and porous media. The packed beds were formed with two different radii of curvature, 71 and 171 mm in diameter, and were filled from steel balls with different particle diameters of 2.00, 2.38, and 3.17 mm. The pressure drop in these spiral packed beds was measured experimentally and flow regimes were determined for each test chamber and ball diameter. In each flow regime, permeabilities, Forchheimer coefficients, and the coefficients corresponding to Ergun constants were calculated. The effect of the curvature ratio was interpreted as the difference from the straight packed beds. Determining the flow regime ranges of curved packed beds can help to better interpret the heat transfer and pumping power of the fluid in these regimes.