Fluidized Bed Adsorption Research Articles

Immobilization of graphene oxide into microbead for fluidized-bed adsorption of methylene blue

Graphene Oxide has shown outstanding performance in the application of adsorption, but these adsorbents are still limited due to some factors. Assembling 2-dimensional (2D) nanomaterials into 3-dimensional (3D) macrostructure (microbead, hydrogel, aerogel, sponge) is a promising alternative to solve the limitation. This paper embedded GO into the two natural polysaccharide polymers (agarose and sodium alginate) to form a 3D-adsorbent. GO-Alg and GO-Agar microbeads were synthesized using the crosslinking method. Analysis techniques such as FT-IR, FESEM-EDX, XRD, and zeta potential were used to characterize the GO-containing microbeads. Adsorption parameters such as adsorbent dosage, pH, contact time, initial ion concentration, and temperature were optimized. Langmuir isotherm and pseudo-first-order kinetic model well fit into the experiment data. The maximum adsorption capacity (qmax) obtained was 120.37 mg.g−1 for removing methylene blue solution. Thermodynamic parameters such as ∆G˚, ∆H˚, and ∆S˚ were determined, and the process was considered endothermic and spontaneous. Reusability results showed good regeneration of GO-Alg microbead up to eight consecutive adsorption-desorption cycles without a significant drop in removal efficiency (> 96%). The application of GO-Alg microbead for MB removal on a packed-bed reactor was investigated in different experimental conditions, and 1 mL.min−1 flow rate with 15 cm bed height revealed a better result. The application of fluidized-bed adsorption was performed to solve the limitation of packed-bed adsorption, and the result showed better adsorption performance than packed-bed using the same operating condition.

Biosorption studies on arsenic (III) removal from industrial wastewater by using fixed and fluidized bed operation

Previously, activated carbon was used as adsorbent for the removal of heavy metals at batch scale and the reported removal efficiency was up to 25 % (while in our technique the efficiency is up to 75%). The large industries operate with continuous processes and discharge large amount of wastewater containing heavy metals. No research was published for continuous operation using fluidized bed adsorption column till now. The novelty of this study is on the mode of operation (continuous operation at large scale under fixed and fluidized bed conditions), Biosorbent activated carbon (AC), and maximum efficiency of arsenic removal (i.e. 75 %). The Biosorbent activated carbon prepared from waste agriculture material. Industrial wastewater consists of many inorganic and organic pollutants which are discharged into water bodies resulting the serious health problems. Now a days, concentration of arsenic has much increased as compared to the permissive concentration level (25mg/L). Therefore, there is need to reduce this concentration up to threshold value (10μg/L). The use of biosorbents for arsenic removal from wastewater has global significance due to its widespread availability and low cost. Biosorption of Arsenic strongly depends on the initial metal concentration, contact time, speed of stirring, pH and temperature. The maximum arsenic as (III) removed at pH-7.5 is 70%, it was improved to 83% by agitation in batch experiments. While in continuous mode experiments (Fixed bed) the bed height and flow rates were varied. At the Fluidized bed experiments, the maximum As (III) removed was 75%. The effects of several factors such as pH, initial solute concentration, biosorbents dose, has been revaluated in this paper. The low cost, easily available biosorbent AC is recommended for removal of arsenic from contaminated wastewaters to bring them in compliance.

A fluidized-bed-riser adsorption system for continuous bioproduct recovery from crude feedstock.

In this work, a novel technique for continuous purification of biologics from a crude feedstock is demonstrated with equipment referred to as Fluidized Bed Adsorption System (FBRAS). The development and validation of such unit operations were performed utilizing lysozyme as a model protein and Relisorb™ SP405/EB as a carrier. The performance of FBRAS to carry out combined clarification and purification was evaluated by capturing of antifungal peptides directly from the lysed broth. The novel technique reduced the number of process unit operations from six to three without having an impact on purity. Overall productivity increased by 250% in comparison to the existing downstream processing routine.

Direct recovery of malate dehydrogenase from highly viscous yeast cell homogenate by a fluidized bed contactor equipped with an agitator

A fluidized bed adsorption system equipped with an agitator was utilized in this study to direct recover malate dehydrogenase enzyme (MDH) from highly turbid yeast cell homogenate. The adsorption and desorption characteristics of STREAMLINE Direct HST, a high-density mixed-mode adsorbent, for the recovery of MDH from the complex cell homogenate were investigated using equilibrium and kinetic studies. The adsorption of MDH was influenced by adsorption pH, ionic strength, feedstock hydrophobicity, and loading of cell homogenate. The elution of MDH from the adsorbent in packed-bed mode was also demonstrated. Subsequently, dynamic binding performance of STREAMLINE Direct HST in stirred fluidized bed adsorption (SFBA) mode was studied using different rotating speeds of agitator, process liquid velocities, and types of cell homogenate. The effect of cell homogenate viscosity on fluidization characteristics was evaluated. MDH was successfully recovered from 100 mL of crude yeast cell homogenate in a single step, recording 80.45% of MDH yield and a purification factor of 73.23. The SFBA process was scaled up using a 50-mm (internal diameter) adsorption column. The scale-up operation showed a similar performance of MDH purification, proving the linear scalability of this adsorption technique. The elution efficiency and purification factor for MDH can be improved to ∼90% and 73–79 folds by using 10 mM NADH/0.1 M NaCl as a specific eluent.

Modeling the effect of humidity and temperature on VOC removal efficiency in a multistage fluidized bed adsorber

The competitive adsorption of volatile organic compounds (VOCs) and water vapor onto beaded activated carbon (BAC) in a fluidized bed adsorber is developed in the form of a two-phase model using the Manes method. The Manes method uses as input single component adsorption isotherms described by the Langmuir model for adsorption of VOCs and the Qi-Hay-Rood (QHR) model for adsorption of water vapor. The effect of temperature is accounted for using the linear van’t Hoff relationship for Langmuir affinity coefficient. The effects of relative humidity (RH) and temperature in the simulations are validated using experimental data, with very good agreement observed (e.g. R2 = 0.98 comparing overall removal efficiencies). Humidity begins to have an effect on the adsorption of 1,2,4-trimethylbenzene (TMB) on BAC starting at 70% RH in the form of a reduction in overall removal efficiency due to fewer available adsorption sites. The overall removal efficiency decreases from 93.0% at 70% RH to 85.4% at 90% RH, and then plateaus with further increase in RH up to 100%. In dry air, temperature variation has a small effect on removal efficiency, showing a reduction in modeled overall removal efficiency from 93.0% to 90.2% when the adsorption temperature increases from 22 to 50 ˚C. On the other hand, at high RH values, temperature has a larger and positive effect on removal efficiency due to RH change. Increasing the temperature of a stream of humid air (RH = 95%) from 22 to 27 °C increases the TMB removal efficiency by 6.9% from 85.3% to 92.2%. Taking into account the effect of humidity and temperature, the model can be used to help optimize fluidized bed adsorber operations in industrial applications.

Modeling the performance of a metal-organic framework (MIL-101) for the adsorption of toluene in an industrial fluidized bed adsorber and comparison to other adsorbent materials

In the present study, the application of a metal–organic framework (MOF) is investigated for the adsorption of toluene in an industrial fluidized bed adsorber. A previously-validated steady-state model is used that takes into account interactions between bubble and emulsion phases. The change in overall removal efficiency and partial pressure profile along the bed is discussed for different design and operating parameters. The performance of MOF (MIL-101) is then compared to that of a beaded activated carbon (BAC), a porous styrene–divinylbenzene polymer (Dowex Optipore V503), and a zeolite (50:50 USY-ZSM-5). The results show an increasing trend for the removal efficiency with an increase in adsorbent feed rate, weir height, or the number of adsorber stages. Increasing gas flowrate or inlet toluene partial pressure decreases the removal efficiency. Examination of the corresponding partial pressure profiles reveals that the major contribution to toluene removal inside the bed shifts from the bottom stages (where the gas enters the bed) to the top stages (where the gas leaves the bed) with increased gas flowrate or inlet partial pressure, or with decreasing the adsorbent feed rate. Comparison of the removal efficiencies obtained with different adsorbent materials shows a general trend as MOF > BAC > polymer > zeolite, except when the adsorbent feed rate is very low or the inlet partial pressure is very high. In those cases, high apparent densities for BAC and zeolite (at constant adsorbent feed rate) create longer adsorbent retention times inside the bed and change the removal efficiency trend to BAC > MOF > zeolite > polymer. Improving the adsorbent retention time by increasing the weir height or the number of stages is suggested to remedy the removal efficiency for adsorbents with low apparent densities (e.g. MOF and polymer).

Modeling the Performance of a Metal-Organic Framework (MIL-101) for the Adsorption of Toluene in an Industrial Fluidized Bed Adsorber and Comparison to Other Adsorbent Materials

Modeling the Performance of a Metal-Organic Framework (MIL-101) for the Adsorption of Toluene in an Industrial Fluidized Bed Adsorber and Comparison to Other Adsorbent Materials

Pseudo counter-current turbulent fluidized bed process with sensible heat recovery for energy-efficient CO2 capture using an amine-functionalized solid sorbent

A fluidized bed adsorption (FLBA) process with internal heat integration is considered an energy-efficient method for large-scale CO2 capture. Herein, we propose a pseudo counter-current FLBA process for post-combustion CO2 capture as a proof-of-concept based on a rationally designed moving bed heat exchanger by incorporating the internal heat integration concept of the conventional amine scrubbing CO2 capture process. The proposed FLBA process consists of an adsorption bed, desorption bed, and moving bed heat exchangers for cooling and heating the solid sorbent. The design of the proposed FLBA process enables internal heat integration by recovering sensible heat from the cooling process. Furthermore, by installing multiple adsorption processes, the pseudo counter-current operation in the adsorption bed enhances the CO2 cyclic capacity of the amine-functionalized solid sorbent with high CO2 recovery. The proposed process complements the two weaknesses of FLBA, namely, large sensible heat and low cyclic capacity of the sorbent. The energy analysis, based on rigorous mathematical modeling, estimates that the energy demand of the optimized FLBA using SiO2/0.37 EB-PEI is approximately 258.6 kWh/t-CO2 with 45% sensible heat recovery. This low energy demand is comparable to that of the most mature amine-based absorption process (271 kWh/t-CO2) owing to the effect of internal heat integration, supporting the feasibility of the FLBA process for post-combustion CO2 capture.

Mathematical correlations in two-phase modeling of fluidized bed adsorbers

Choosing proper formulas for estimating different variables is imperative when modeling a fluidized bed using two–phase theory. In this study, a two–phase model was used to model the adsorption of volatile organic compounds (VOC) in a multistage fluidized bed adsorber. Two different approaches were used to describe gas flow and mixing in the emulsion phase, perfectly mixed (EGPM: Emulsion Gas – Perfectly Mixed) and plug flow (EGPF: Emulsion Gas – Plug flow). The impact of different formulas for estimating bubble size, bed porosity at minimum fluidization velocity, adsorption and interphase mass transfer coefficients, as well as tortuosity on the performance of the model was determined by comparing the model outcomes with experimental data. Finally, using a large dataset obtained from fluidized bed adsorption systems with different adsorbents, adsorbates, bed sizes, and operating conditions, a broadly-applicable set of formulas was suggested which could be used to describe the behavior of different countercurrent fluidized bed adsorbers. From the results, the two–phase model could successfully predict the experimental data, with EGPF showing better performance than EGPM. Proper use of formulas, especially those describing bed voidage and interphase mass transfer coefficient, could markedly improve the performance of the two-phase model. The two-phase model using the set of formulas proposed here was able to accurately replicate a large dataset of fluidized bed adsorption experiments over a wide range of operating conditions.

Economic evaluation for four different solid sorbent processes with heat integration for energy-efficient CO2 capture based on PEI-silica sorbent

An amine-functionalized solid sorbent-based process with heat integration is considered an energy-efficient method for large-scale CO2 capture. Herein, we propose a techno-economic analysis (TEA) of four different solid sorbent processes for post-combustion CO2 capture with internal heat integration as an alternative to the conventional amine scrubbing process. Our proposed processes are fluidized bed adsorption, fixed bed adsorption, moving bed adsorption, and rapid thermal swing adsorption and involve continuous adsorption, heating, desorption, and cooling. In addition, the four processes use an amine-functionalized solid sorbent, SiO2/0.37 EB-PEI, which was transformed into powder, pellet, and hollow fiber to reflect the characteristics of each process. The proposed processes enable internal heat integration by recovering sensible heat from the cooling process and further enhance the CO2 cyclic capacity of amine-functionalized solid sorbents with high CO2 recovery by performing adsorption heat removal. Most importantly, our TEA based on rigorous mathematical modeling revealed that the CO2 capture cost of the four solid sorbent-based processes was approximately 48.1–75.2 $/t-CO2, with a 45%–58% sensible heat recovery. Such a low CO2 capture cost is comparable to that of the most mature amine-based absorption process (62.8 $/t-CO2), owing to a combination of internal heat integration and enhanced CO2 cyclic capacity. The results support the feasibility of four solid sorbent-based processes for post-combustion CO2 capture.

Adsorption of methylene blue dye from the aqueous solution via bio-adsorption in the inverse fluidized-bed adsorption column using the torrefied rice husk

In this work, the inverse fluidized-bed bio-adsorption column is applied for the first time and is demonstrated using the torrefied rice husk (TRH) for the removal of methylene blue from the solution. The bio-adsorbents were characterized by BET, FI-IR, and SEM. The inverse fluidized-bed adsorption column using TRH becomes saturated in the 95-min continuous adsorption, during which the breakthrough time is 22 min, the overall MB removal (R) is 84%, and the adsorption capacity (Qexp) on the TRH is 6.82 mg g−1. These adsorption characteristics are superior to those in the fixed-bed adsorption column (R of 52% and Qexp of 2.76 mg g−1) at a lower flow rate (100 vs. 283 cm3 min−1). Torrefaction of RH significantly increases the surface area (28 vs. 9 m2 g−1) and enhances the surface functional groups, leading to an improved maximum equilibrium adsorption amount from 21.5 to 38.0 mg g−1 according to Langmuir model in the batch adsorption system. Besides, the increased Qexp on the TRH is also obtained in the inverse fluidized-bed (5.25 vs. 2.77 mg g−1, 89% higher) and the fixed-bed (2.76 vs. 1.53 mg g−1, 80% higher) adsorption columns compared to that on the RH.

LDF based parametric optimization to model fluidized bed adsorption of trichloroethylene on activated carbon particles

Trichloroethylene (TCE) is largely used in industries as a cleaning and degreasing solvent. TCE is a potential carcinogen and is known to cause organ damage when exposed to prolonged higher concentrations. Numerical simulation of fixed and fluidized bed adsorption of TCE can help in the development of efficient adsorption processes to prevent industrial workers in the vicinity from acute TCE exposure. In the present work, a parametric optimization based numerical experimentation algorithm is implemented by open-source computational solvers to model fixed and fluidized bed adsorption of trichloroethylene vapors on activated carbon. The algorithm optimizes four parameters pertaining to linear driving force (LDF) formulation of surface barrier and microporous diffusion. The optimized parameters were utilized to evaluate ζ¯, a dimensionless number defined as the temporal and spatial average ratio of surface barrier diffusion resistance to microporous diffusion resistance. The average value of ζ¯ is 0.139 for fixed bed operation (u/umf=0.7), 1.130 for fluidized bed operation (u/umf=1), 4.436 for fluidized bed operation (u/umf=1.5) and 6.317 for fluidized bed operation (u/umf=2). Therefore, the dimensionless number ζ¯ may serve to predict the extent of change in amount adsorbed per unit adsorbent mass with change in fluidization velocity.

Process intensification in binary adsorption of VOC-water vapor on zeolite in a countercurrent fluidized bed adsorber

In this study, fast ideal adsorbed solution theory was coupled with a two-phase bubbling bed approach to describe the adsorption of volatile organic compounds (VOCs) on zeolite in the presence of water vapor in a multistage fluidized bed adsorber. The binary adsorption of VOC-water vapor was predicted using their single component adsorption isotherms. The model was verified by experimental data obtained at a wide range of operating conditions before being used for studying the process intensification. Validation tests revealed that the model could accurately predict the experimental removal efficiencies (R2 = 0.94), as well as VOC concentration profiles inside the bed (R2 = 0.98). The intensification simulations showed that increasing the adsorbent feed rate is effective when there is a need for more adsorption sites (e.g. at high inlet concentrations), and is quite ineffective when the adsorption process is limited by low solid-gas contact time (e.g. high air flow rates). Increasing the adsorbent feed rate can also diminish the interference of water vapor in adsorption of VOC (even at RH as high as 75%). Reducing air flow rate at constant VOC load is always effective specially when there are enough adsorption sites available (e.g. high adsorbent feed rate, and low VOC loads and RHs). Similarly, increasing the number of stages can effectively improve the fluidized bed performance at high adsorbent feed rates and low VOC inlet concentrations and RHs. Using 3 adsorbers of 2 stages instead of 1 adsorber of 6 stages can improve the removal efficiency up to 34.5% in the range of operating conditions simulated. While having the same high weir height along the bed yields better performance than having the same low weir height, an optimized arrangement of weir heights in a descending order from the top to the bottom of the bed would maximize the removal efficiency.

Modeling the Performance of a Metal-Organic Framework (Mil-101) for the Adsorption of Toluene in an Industrial Fluidized Bed Adsorber and Comparison to Other Adsorbent Materials

Modeling the Performance of a Metal-Organic Framework (Mil-101) for the Adsorption of Toluene in an Industrial Fluidized Bed Adsorber and Comparison to Other Adsorbent Materials

Purification of lysozyme from chicken egg white by high-density cation exchange adsorbents in stirred fluidized bed adsorption system

Lysozyme from crude chicken egg white (CEW) feedstock was successfully purified using a stirred fluidized bed adsorption system ion exchange chromatography where STREAMLINE SP and SP-XL high density adsorbents were selected as the adsorption carrier. The thermodynamic and kinetic studies were carried out to understand the characteristics of lysozyme adsorption by adsorbents under various conditions, including adsorption pH, temperature, lysozyme concentration and salt concentrations. Results showed that SP and SP-XL adsorbents achieved optimum lysozyme adsorption at pH 9 with capacity of ~139.77 and ~251.26 mg/mL, respectively. The optimal conditions obtained from batch studies were directly employed to operate in SFBA process. For SP-XL adsorbent, the recovery yield and purification factor of lysozyme were 93.78% and ~40 folds, respectively. For SP adsorbent, lysozyme can be eluted ~100% with purification factor of ~26 folds. These two adsorbents are highly suitable for use in direct recovery of lysozyme from crude CEW.

Generation Process and Performance Evaluation of Engineered Microsphere Agarose Adsorbent for Application in Fluidized-bed Systems

In this research, the generation process of engineered microsphere agarose adsorbent has been explained that has surfaces with different active sites to adsorb protein nanoparticles into the fluidized-bed system. Also, excellent selectivity of protein nanoparticles, high adsorption capacity, and fast equilibrium rate through the eco-friendly polymeric adsorbents were vital aims in here. Hence, agarose as a cheap, and abundant natural polymer, with a ferromagnetic condenser, and dye-ligand adsorbents, were employed to generate the engineered microsphere agarose adsorbent. Then, the performance of produced adsorbents was evaluated in the batch and fluidized-bed system. Scanning electron microscopy, atomic force microscopy, and optical microscope were used. Results showed the shape of adsorbents is spherical, with the size distribution range of 50-250 µm, the porosity of around 90%, and the wet density of 2.6 g/mL. Then, to compare the performance of the engineered adsorbents in a fluidized-bed system, the dye ligand was immobilized on the Streamline™. The obtained results were compared at the same conditions. In batch adsorption tests, the results of lactoferrin nanoparticle adsorption were shown higher dynamic binding capacity with engineered microsphere agarose adsorbents. Also, the results demonstrated that more than 75% of the adsorption process occurred in the first half-hour, which is a very suitable time for a fluidized-bed system. Also, adsorption equilibrium data were evaluated with isothermal adsorption models, and Langmuir’s model suits the data, and the maximum of adsorption was close to 45.3 mg/mL adsorbent. The fluidized-bed adsorption tests showed that engineered adsorbents gained a sound breakthrough performance at high flow velocity and upper dynamic binding capacity compared to commercial adsorbents. The dynamic binding capacity at 10% breakthrough achieved 71% of the flooded adsorption process at the major fluid velocity of 348 cm/h, so the engineered adsorbent has been proved the good potential for use in high flow rate fluidized-bed systems.

Modeling VOC adsorption in lab- and industrial-scale fluidized bed adsorbers: Effect of operating parameters and heel build-up

Scale-up and optimization of fluidized beds are challenging due to the difficulty in accounting for the interrelated effect of various phenomena, which are typically described by empirical and/or semi-empirical equations. In this study, a two-phase model was introduced to simulate the adsorption of VOCs on beaded activated carbon (BAC) in a lab-scale fluidized bed adsorber. The model assumes the presence of a bubble phase free from adsorbent particles, and an emulsion phase composed of the adsorbent particles and interstitial gas. The versatility of the proposed model was then evaluated using data from an industrial scale adsorber with different operating conditions, adsorbent properties, and bed geometry. The response of the model to the operating conditions (adsorbent feed rate, air flow rate and initial concentration) showed better agreement with the experimental lab-scale data when the emulsion gas in two-phase model was considered in plug flow than in perfectly-mixed flow (R2 = 0.96 compared to 0.91). To simulate the performance of BACs with different service lifetimes (degree of exhaustion as a result of heel developed inside their pores), the main characteristics of the BACs (pore diameter, porosity, and adsorption capacity) were first correlated to their apparent densities. The model could accurately predict the experimental lab-scale VOC concentrations in each stage (R2 = 0.92) as well as overall removal efficiencies (R2 = 0.99) for BACs ranging from virgin to fully-spent. Finally, the model was used to predict the performance of an industrial-scale fluidized bed adsorber for VOC removal at different operating conditions and apparent densities. Predicted and measured VOC removal efficiencies were in good agreement (R2 = 0.94). Although the model was verified for adsorption of VOCs on BAC, the modeling approach presented in this study could be used for describing adsorption in different adsorbate-adsorbent systems in multistage counter-current fluidized bed adsorbers.

Modeling VOC adsorption in a multistage countercurrent fluidized bed adsorber

The adsorption of 1,2,4-trimethylbenzene (TMB) on beaded activated carbon (BAC) in a six-stage countercurrent fluidized bed adsorber was simulated employing a two-phase model, assuming the gas in particulate phase to be either in plug flow (EGPF model) or in perfectly mixed flow (EGPM model). A rather simple model considering equilibrium state on each stage (Equilibrium model) was also used for comparison. Simulation results were compared with experimental data obtained at different values of adsorbent feed rate, superficial gas velocity, TMB initial concentration and weir height (which influences the effective bed height). The results demonstrate that the Equilibrium model overpredicts the overall removal efficiencies when the adsorbate-adsorbent system is far from equilibrium condition. On the other hand, both EGPF and EGPM show good agreement with the experimental results over industrially relevant operating conditions. Stage-wise removal efficiencies show that the EGPF model tends to predict removal efficiency better than EGPM when the weir height is high. The sensitivity analysis of the EGPM model indicates that internal diffusion within the BAC is rate-limiting for adsorption, while BAC diameter strongly influences the overall removal efficiency and can be optimized for different conditions. The effect of changes in BAC adsorption capacity on overall removal efficiency depends on the number of available adsorption sites, as well as proximity to equilibrium condition. The model developed in this study is also able to predict the effect of the number of stages on overall removal efficiency of the adsorber. The results of this study could pave the way for optimizing the design and operation of fluidized bed adsorbers, leading to cost savings and performance improvements.

Pilot testing of CO2 capture from a coal-fired power plant—Part 2: Results from 1-MWe pilot tests

Abstract Using a 1-MWe slipstream pilot plant, solid-sorbent-based post-combustion CO2 capture was tested at a coal-fired power plant. Results from pilot testing were used to develop a preliminary full-scale commercial design. The sorbent selected for pilot-scale evaluation during this project consisted of an ion-exchange resin that incorporated amines covalently bonded to the substrate. A unique temperature-swing-absorption (TSA) process was developed that incorporated a three-stage fluidized-bed adsorber integrated with a single-stage fluidized-bed regenerator. Overall, following start-up and commissioning challenges that are often associated with first-of-a-kind pilots, the pilot plant operated as designed and expected, with a few key exceptions. The two primary exceptions were associated with: (i) handling characteristics of the sorbent, which were sufficiently different at operating temperature than at ambient temperature when design specifications were established with lab-scale testing; and (ii) CO2 adsorption in the transport line between the regenerator and adsorber that preloaded the sorbent with CO2 prior to entering the adsorber. Results from the pilot programme demonstrate that solid-sorbent-based post-combustion capture can be utilized to achieve 90% CO2 capture from coal-fired power plants.

Design and proof of concept of a continuous pressurized multi-stage fluidized bed setup for deep sour gas removal using adsorption

Pressure swing adsorption (PSA) processes are frequently used in the (petro)chemical industry, but they suffer from ineffective use of the sorbent and slow heat transfer. A pressurized multi-stage fluidized bed (MSFB) for continuous PSA is proposed in this work to overcome these drawbacks. A one stage fluidized bed adsorber was used to determine minimum fluidization velocities of the used amine sorbent at various pressures up to 10 bara. The design of a pilot scale experimental setup is described, together with supporting experiments to show the proof of concept. Removal from 37,000 mol ppm CO2 to <10 mol ppm CO2 in a few seconds was demonstrated in the pressurized MSFB adsorber. The tray efficiencies were high: often larger than 0.85. Using a numerical particle model, it was concluded that the CO2 adsorption rate is controlled via intraparticle mass transfer.