Bed Agglomeration Research Articles

Effect of Fluidized Bed Agglomeration on Rheological and Physical Properties of Soy Protein-Enriched Milk Powder for Dietary Supplementation in Sarcopenia.

Recently, many elderly people in Korea have been consuming protein-enriched milk powders for dietary supplementation in sarcopenia. In general, protein powders are manufactured using a spray dryer, and their fine particles result in poor instant properties. Fluidized bed agglomeration (FBA) is an effective method for improving the physical properties of protein powders via particle granulation, such as flowability and wettability. Therefore, the effects of FBA on the rheological and physical properties of isolated soy protein (ISP)-enriched skim milk powder (SMP) were investigated in this study. The size of ISP-enriched SMP particles was significantly increased by FBA, leading to changes in the Carr index and Hausner ratio from fair flowability and intermediate cohesiveness to good flowability and low cohesiveness, respectively. The wettability of the granulated particles was also improved by FBA, and they exhibited a shorter wetting time below 10 s. However, a slight color change was observed after the FBA process. These findings contribute to the production of protein-enriched food powders with improved properties.

Agglomeration of Spray-Dried Milk Powder in a Spray Fluidized Bed: A Morphological Modeling

The type of solid substrate plays a critical role in determining the kinetics of the spray fluidized bed (SFB) agglomeration process. In the case of porous (also soft) primary particles (PPs), droplet aging is due to imbibition and drying. The surface properties of the substrate also change due to imbibition. The focus of the present work is to simulate the agglomeration of the spray-dried milk powder using the Monte Carlo (MC) method coupled with a drying-imbibition model. In order to extract the morphology of the formed agglomerates, an aggregation model is employed. Further, this aggregation model is employed to predict the number of positions on the PPs (later agglomerates) for droplet deposition; previously, the ‘concept of positions’ was used. The transient growth of different milk powders (whole and skim) is depicted using the enhanced MC model. The enhancement in the droplet deposition model had a prominent influence on the overall kinetics of agglomeration. As expected, this enhanced MC model predicted that the agglomeration rate of skim milk powder is higher than that of whole milk powder.

Fluidised bed agglomeration of strawberry powder mix obtained for spray drying

BACKGROUND: The microencapsulation process using spray drying (SD) represents an effective alternative in protecting the active components present in strawberries. However, microcapsules of strawberry powder mixtures present problems of instantanisation and flowability; an aspect that can be solved by agglomeration of the particles. OBJECTIVE: The aim of this study was to evaluate the influence of the fluidised bed agglomeration process on the flow, instantaneity and antioxidant properties of strawberry powder obtained by SD. METHODS: The response surface methodology (RSM) was used with a centred composite central design (α=1), considering the factors: fluidisation air temperature (50-70°C), time (30-50 min) and atomisation air pressure of the binder agent (1-2 bar). RESULTS: An increase in particle size was observed in the agglomeration process; the agglomerated particles showed a decrease in wetting time, the agglomerates of strawberry powder mixtures presented excellent instantanisation and fluidity, solving the problems identified in the microcapsules obtained by SD. CONCLUSIONS: Although the moisture and aw levels were increased in the agglomeration process, the values are within the microbiological and physicochemical food safety range; moreover, there was no effect on the phenol content and antioxidant capacity. The experimental optimisation achieved desirability of 68.4%, the optimum conditions being 70°C, 30 min and 1 bar.

Potassium capture by ilmenite ore as the bed material during fluidized bed conversion

Biomass is a complex fuel containing a heterogeneous mixture of organic matter and, to a lesser extent, inorganic matter. Inorganic ash-forming elements can cause serious ash-related problems in fluidized bed combustion systems, such as bed agglomeration, fouling and corrosion of heat transfer equipment. Potassium (K), a biomass ash component, is a major contributor to these phenomena. The aim of this work, in the context of high-potassium biomass fuel combustion, is to estimate the potential for the absorption of potassium by bed materials under different oxygen carrier aided combustion (OCAC) operating conditions, in terms of reaction gas composition, exposure duration, bed temperature, potassium salt type, and concentrations of potassium salt. Experiments were conducted with an electrically heated fluidized bed reactor (FBR). The potassium solution is injected into the dense bed region via a small tube. In the studied temperature range of 700–900 °C, the captured K amount increases significantly at temperatures lower than 850 °C. The gas atmosphere had a less notable effect on K capture, but the capture rate of potassium dropped to half after the K-solution was switched from KOH to K2CO3 in the CO2 gas atmosphere. The percentage of injected potassium that is captured is high (∼40–60 wt%) in the first 5 h, and it remains at a high level of about 35 wt% after 25 h. KTi8O16 is the only crystalline K-compound found in the bed solid samples when ilmenite ore was used as bed material. KAlSi3O8 and K0.43(NH4)0.53Al0.89Si2.11O6 were detected when olivine sand was used as bed material. Thermogravimetric analysis (TGA) indicated no significant effect of the spent ilmenite on its redox reactivity after its reaction with K-solutions in the fluidized bed; however, the O2-carrying capacity of spent ilmenite shows a 7 % reduction after 25 h of exposure to potassium in the fluidized bed.

Calcite or Kaolinite Addition for Mitigating Bed Agglomeration during Combustion and Steam Gasification of Potassium-Rich Agricultural Residues with Olivine as the Bed Material

Calcite or Kaolinite Addition for Mitigating Bed Agglomeration during Combustion and Steam Gasification of Potassium-Rich Agricultural Residues with Olivine as the Bed Material

Co-processed tablet excipient composition, its preparationand use: US10071059 B2: patent spotlight.

Co-processing involves the incorporation of one excipients into the particle structure of other excipients to overcome the deficiencies of each excipients. The current patent describes the co-processing of microcrystalline cellulose and mannitol via fluid bed agglomeration with an aim to limit the use of lubricant in tablet composition. The co-processed excipients blend was compared with the physical blend of excipients and characterized for scanning electron microscopy, disintegration and hardness. The average particle size of co-processed excipients was less than 0.55mm, characterized by large individual lactose-coated particles whereas, the physical blend particles are uncoated and irregular in shape. Tablets made from both physical blend and co-processed excipients were compared. As per the hardness and disintegration studies, with increase in mixing time of excipients both hardness and disintegration time decreases.

Research on the mechanism of bed agglomeration and superheater fouling in CFB boiler fired pure petroleum coke

AbstractCirculating fluidized bed combustion is an effective method for the clean and efficient utilization of high‐sulphur petroleum coke. In the actual production and operation process, there are serious problems of bed agglomeration and superheater fouling. The chemical and mineral compositions of the deposition were analyzed by X‐ray diffraction (XRD) and X‐ray fluorescence spectroscopy (XRF), and the effects of CaO sulphation and V2O5 on bed agglomeration and superheater deposits were studied through targeted experiments. The research results show that the sulphation process of CaO is the cause of bed agglomeration, and the superheater fouling is the result of the combined action of K2SO4 condensation and CaO sulphation; V2O5 in petroleum coke ash catalyzes the oxidation reaction of SO2 to accelerate the sulphation of CaO, thereby accelerating the development of bed agglomeration and superheater fouling.

Bed agglomeration during fast pyrolysis of bio-oil derived fuels in a fluidized-bed reactor

• Agglomeration yields of fuel blend and slurry fuels are lower than that of bio-oil. • Methanol and biochar have positive effect on reducing bed agglomeration. • Bed agglomeration of bio-oil derived fuels is mainly governed by tar formation. This study investigates the bed agglomeration during fast pyrolysis of bio-oil derived fuels in a fluidized-bed reactor at 800 °C, including crude glycerol/methanol/bio-oil (CGMB) blend, bio-oil/biochar (BB) and CGMB/biochar (CGMBB) slurry fuels. The results show that the agglomeration yields of CGMB blend, as well as BB and CGMBB slurries are 13.0%, 11.2% and 8.6% respectively, which are all lower than that of bio-oil (18.8%). Investigations on the influence of methanol, CG and biochar on bed agglomeration reveal the positive effect of methanol and biochar as they both reduce the tar formation for different reasons, while CG exhibits limited influence. The tar yields of CGMB, BB and CGMBB are 8.3%, 2.1% and 2.7% respectively, which are all lower than that of bio-oil with tar yield being 16.4%. The coke yield of CGMB is 4.9% and is lower than that of bio-oil which is 7.0%, while both BB and CGMBB have a higher coke yield (10.8% and 10.1% respectively) that mainly due to the presence of biochar. The agglomeration yield due to tar formation and tar yield exhibits a positive linear correlation, while bed agglomeration due to coke formation and coke yield exhibits irrelevant relationship. This clearly suggests the bed agglomeration of bio-oil derived fuels is mainly governed by tar formation.

Improved Flowability and Wettability of Whey Protein-Fortified Skim Milk Powder via Fluidized Bed Agglomeration.

Recently, protein-fortified milk powders are being widely consumed in Korea to prevent sarcopenia, and the demand for high-protein food powders is continuously increasing in the Korean market. However, spray-dried milk proteins have poor flowability and wettability owing to their fine particle sizes and high inter-particle cohesive forces. Fluidized bed agglomeration is widely used to improve the instant properties of food powders. This study investigated the effect of fluidized bed agglomeration on whey protein isolate (WPI)-fortified skim milk powder (SMP) at different SMP/WPI ratios. The fluidized bed process increased the particle size distribution, and agglomerated particles with grape-like structures were observed in the SEM images. As the size increased, the Carr index (CI) and Hausner ratio (HR) values of the agglomerated WPI-fortified SMP particles exhibited excellent flowability (CI: <15) and low cohesiveness (HR: <1.2). In addition, agglomerated WPI-fortified SMP particles exhibited the faster wetting time than the instant criterion (<20 s). As a result, the rheological and physical properties of the WPI-fortified SMP particles were effectively improved by fluidized bed agglomeration. However, the fluidized bed agglomeration process led to a slight change in the color properties. The CIE L* decreased, and the CIE b* increased because of the Maillard reaction. The apparent viscosity (ηa,10) and consistency index (K) values of the rehydrated solutions (60 g/180 mL water) increased with the increasing WPI ratio. These results may be useful for formulating protein-fortified milk powder with better instant properties.

Development of biomass-fired circulating fluidized bed boiler with high steam parameters based on theoretical analysis and industrial practices

Further improvement of steam parameters is essential to developing biomass-fired circulating fluidized bed (CFB) boiler technology, which necessitates solving severe slagging, fouling, agglomeration, and corrosion problems caused by the high content of alkali metals and chlorine in biomass fuels. Studies indicate that by arranging the high-temperature heating surfaces inside the furnace, the slagging and corrosion of the surface can be effectively lightened through the continuous wash and cleaning by solid circulating ash. Meanwhile, the ash fouling on the convective heating surface can be mitigated by applying in-line tube bundles with large intercept, small tube diameter, and parallel flow design. In addition, the significant improvement of circulating loop performance can not only alleviate the bed agglomeration but also help increase the boiler efficiency, decrease slagging on the heating surface, and reduce the NOx emission. Series biomass-fired CFB boilers with high steam parameters have been successfully established based on these technical routes, including one 125 MW super-high pressure boiler with the largest capacity and the highest steam parameters in Asia. Lone-term operational data from four commercial CFB boilers show that they can operate stably within a wide range of load ratios, from 30% to 105%, and continuous operation time can last more than half a year. Moreover, the boiler efficiency can reach up to 90%–93.5%, and the NOx and SO2 emissions can be stably controlled lower than the ultra-low emission standard in China. The variation of some operation parameters with boiler load was also discussed in this work.

Optimization of fluidized bed agglomeration process of a pineapple powder mixture using a binder solution of ginger extract and vitamin C

The aim of this research was to optimize fluidized bed agglomeration process of a pineapple powder mixture using a binder solution of ginger extract and vitamin C. The process was evaluated using a central composite design and analyzed using the response surface methodology. The independent variables were considered: fluidization air inlet temperature (50–70 °C), process time (30–50 min), and atomization pressure of binder solution (1–2 bar). The experimental optimization of multiple responses (desirability 74%) defined the independent variables as fluidization air inlet temperature 70 °C, process time 43.7 min, and atomization pressure of binder solution 1.3 bar. The dependent variables were: moisture (4.7 ± 0.1%), solubility (80.2 ± 2.2%), hygroscopicity (20.3 ± 1.8%), wettability (17.8 ± 0.6 s), Carr Index (10.7 ± 1.9%), Hausner ratio (1.12 ± 0.02), total polyphenols (310.1 ± 4.3 mg GAE/100gdb), total flavonoids (202.9 ± 7,2 mg QE/100gdb), ABTS (198.8 ± 12.1 mg TE/100gdb), DPPH (239.25 ± 9,0 mg TE/100gdb), vitamin C (179.2 ± 4.3 mg AA/100gdb) and β-carotene (544.4 ± 8.9 μg/100gdb). The agglomerated pineapple powder mixture presented better flow and instantaneous properties than the pineapple powder mixture obtained by spray drying. In addition, the product retains levels of active components that guarantee an important source of antioxidants.

Impact of the agglomeration process on the flow, reconstitution, and antioxidant properties of an Andean berry powder mix

BACKGROUND: There is consumer interest in berries due to their nutritional properties, especially biologically active compounds. Spray drying technologies improve products stability and shelf life, and the agglomeration process subsequently enhances powder instantaneousness and flow properties. OBJECTIVE: The aim was to evaluate the effect of the fluidized bed agglomeration process on flow, reconstitution, and antioxidant properties of cape gooseberry, strawberry, and blackberry powder mix obtained by spray drying and a water and vitamin C binding solution. METHODS: A face-centered central composite design with 15 experiments was used; independent variables were fluidization temperature (T), binder solution atomization pressure (P), and process time (t), while dependent variables were moisture, solubility, wettability, particle size, antioxidant capacity, total phenols, Vit. C, β-carotenes (β-car), and total anthocyanins. RESULTS: The best process conditions from experimental optimization were T = 70 °C, P = 1.1 bar, and t = 29.1 min. This agglomerated product had low moisture values, good solubility, and 0.5 min wettability; the values for Vit. C = 246.4±3.4 mg/100 g db, β-car = 4.0±0.5 mg/100 g db, and total anthocyanins = 230.7±3.0 mg C3G/100 g db were noteworthy. CONCLUSIONS: An agglomerate berry-based powder product was obtained with 100% Vit. C RDA (Recommended Dietary Allowances) and 15% vitamin A RDA. Flow and instantaneousness properties of the agglomerated powder also significantly improved with the applied process.

Improvements in the Physical Properties of Agglomerated Milk Protein Isolate/Skim Milk Powder Mixtures Via Fluidized Bed Agglomeration

Protein-enriched dairy powder is widely consumed to promote muscle synthesis. Recently, in Korea, elderly people have also begun consuming protein powder products to prevent muscle loss. However, these protein-enriched powders have poor flowability and hydration properties because of the fine particles of spray-dried milk protein powder. Therefore, in this study, the fluidized bed agglomeration process was used to solve these problems. The rheological and physical properties of milk protein isolate (MPI)/skim milk powder (SMP) mixtures were effectively improved via fluidized bed agglomeration. The particle size of the MPI/SMP mixtures significantly increased from 35.7–58 μm to 118–136 μm, the flowability level improved from fair (21.4–26.3) to good (15.7–16.3), and the cohesiveness level changed from intermediate (1.27–1.36) to low (1.18–1.19) after fluidized bed agglomeration. In addition, the wetting time of the agglomerated MPI/SMP mixtures was effectively reduced to 4.67–58.3 s by fluidized bed agglomeration. These findings may be useful for manufacturing protein-enriched dairy powders with good instant properties.

Torrefaction of Pulp Industry Sludge to Enhance Its Fuel Characteristics

Recently, under COP26, several countries agreed to phase-out coal from their energy systems. The torrefaction industry can take advantage of this, as the fuel characteristics of torrefied biomasses are comparable to those of coal. However, in terms of economic feasibility, torrefied biomass pellets are not yet competitive with coal without subsidies because of the high price of woody biomass. Thus, there is a need to produce torrefied pellets from low-cost feedstock; pulp industry sludge is one such feedstock. In this context, this study was focused on the torrefaction of pulp industry sludge. Torrefaction experiments were carried out using a continuous reactor, at temperatures of 250, 275, and 300 °C. The heating value of the sludge increased from 19 to 22 MJ/kg after torrefaction at 300 °C. The fixed carbon content increased from 16 wt.% for dried pulp sludge to 30 wt.% for torrefied pulp sludge. The fuel ratio was in the range of 0.27 to 0.61. The ash content of the pulp sludge was comparable to that of agricultural waste, i.e., around 12 wt.% (dry basis). The cellulose content in the sludge was reduced from 35 to 12 wt.% at 300 °C. Ash related issues such as slagging, fouling, and bed agglomeration tendency of the sludge were moderate. This study shows that torrefaction treatment can improve the fuel properties of pulp industry sludge to a level comparable to that of low-rank coal.

The use of kaolin and dolomite bed additives as an agglomeration mitigation method for wheat straw and miscanthus biomass fuels in a pilot-scale fluidized bed combustor

Renewable biomass fuels are frequently used for power generation. Biomass ash causes bed agglomeration in fluidized bed boilers due to the formation of alkali silicate melts. Very few prior studies have tested dolomite and kaolin bed additives for agglomeration mitigation with agricultural biomasses. In this work, pelletized miscanthus and wheat straw were tested in a pilot-scale 65kWth fluidized bed combustor with varying dosages of dolomite and kaolin on a silica sand bed. Neither additive improved defluidization time with wheat straw, whereas additive use at all dosages prevented bed defluidization with miscanthus. Agglomerates were studied through a novel, detailed SEM/EDX analysis across structural features. SEM/EDX analysis presented evidence of chemical reaction between both additives and fuels. Potassium in ash migrated into kaolin particle at depths of up to 60 μm. With dolomite, calcium and magnesium raised melt temperatures. Thermochemical modelling of the ash and additive combinations predicted that additive use would substantially reduce ash melt formation. It is proposed that the wheat straw pellet acted as a “ready-made” agglomerate structure due to release of molten ash to the pellet surface which bed material then sticks to, hence the lack of change to defluidization time regardless of additive use. Future studies into this behaviour would improve additive use.

Investigations on the Effect of Pre-Treatment of Wheat Straw on Ash-Related Issues in Chemical Looping Gasification (CLG) in Comparison with Woody Biomass

Biomass chemical looping gasification (BCLG) is a promising autothermic route for producing sustainable, N2-free, and carbon neutral syngas for producing liquid biofuels or high value hydrocarbons. However, different ash-related issues, such as high-temperature corrosion, fouling and slagging, bed agglomeration, or poisoning of the oxygen carrier might cause significant ecologic and economic challenges for reliable implementation of BCLG. In this work, lab-scale investigations under gasification-like conditions at 950 °C and thermodynamic modelling were combined for assessing the influence of composition, pre-treatment methods, such as torrefaction and water-leaching, and Ca-based additives on the release and fate of volatile inorganics, as well as on ash melting behavior. A deep characterization of both (non-)condensable gas species and ash composition behavior, joint with thermodynamic modelling has shown that different pre-treatment methods and/or Ca-additives can significantly counteract the above-mentioned problems. It can be concluded that torrefaction alone is not suitable to obtain the desired effects in terms of ash melting behavior or release of problematic volatile species. However, very promising results were achieved when torrefied or water-leached wheat straw was blended with 2 wt% CaCO3, since ash melting behavior was improved up to a similar level than woody biomass. Generally, both torrefaction and water-leaching reduced the amount of chlorine significantly.

Experimental study and SEM-EDS analysis of agglomerates from gasification of biomass in fluidized beds

Fluidized bed gasification is an attractive conversion technology for biomass. However, processing biomass in fluidized beds suffers from ash related problems. In this work, bed agglomeration of wood pellets and grass pellets was compared, focusing on de-fluidization temperatures and variation in microstructure and composition of agglomerates. The results showed that both biomasses form agglomerates at temperatures between 700 °C and 900 °C. After each test run, residual sand and agglomerates were discharged and the ash/bed material ratio was calculated. Larger amount of accumulated ash and agglomerates were collected from the gasification of grass pellets than that from wood pellets, indicating that different mechanisms are present in the agglomerate formation. The ash/bed material varied from 3 to 10 wt% for the grass pellets and from 0.8 to 1.5 wt% for the wood pellets. A scanning electron microscope with energy dispersive X-ray spectroscopy was used for characterizing morphology and elemental composition of the agglomerates. The findings show that the surface of agglomerates from grass were dominated by Si, Ca and K, while the surface of agglomerates from wood mainly were dominated by Si and K. The cross-sectional analysis concluded that Si, Ca, and K are the ash forming elements that play the most significant role in agglomeration processes.

Bubbling fluidized bed biomass gasification using a two-stage process at 600 °C: A way to avoid bed agglomeration

Air gasification of wood pellet was conducted using a two-stage gasifier consisting of a fluidized bed gasifier and a tar-cracking reactor filled with active carbon. The main aim of this study was to show that smooth gasification was possible at about 600 °C, where bed agglomeration could be avoided. Another important part of this study was to observe whether the low-temperature gasification could produce a producer gas with a similar gas quality to those obtained at high gasification temperatures. In the two-stage air gasification of wood pellet, active carbon showed an excellent performance in both removing tar and increasing H2 production. The gas quality of the producer gas obtained at the fluidized bed gasifier temperature of about 600 °C proved to be similar to that obtained at about 800 °C. Further, the gas quality of the producer gas obtained without an electrostatic precipitator turned out to be comparable to that obtained with an electrostatic precipitator A long-term two-stage gasification (200 min) was conducted successfully without any operational problems, producing a H2-rich (15 vol%) gas. The sole tar component of the producer gas from the long-term gasification was toluene, the content of which in the gas was only 8 mg/Nm3.

Characteristics of Air Gasification of 10 Different Types of Plastic in a Two-Stage Gasification Process

In this study, air gasification of 10 different types of plastic was conducted using a two-stage gasifier consisting of a fluidized bed gasifier and a tar-cracking reactor filled with activated carbon as a tar removal additive. The study aimed to show characteristics of the producer gases obtained from the two-stage gasification of individual plastics. Ten individual plastics were grouped into four according to their chemical compositional characteristics. In the experiment, product gases having tar contents in the range from 132 mg/Nm3 (ABS) to 0 mg/Nm3 (polyethylene and polyamide) were obtained. In the gasification of plastics having aromatic rings, the productions of char and tar in gas were higher than those of aliphatic plastics. The gasification of aliphatic plastics without heteroatoms, such as polyethylene and polypropylene, favored H2 production and had a maximum value of 26 vol %. Activated carbon played a significant role in lowering the tar content in gas and enhancing H2 production. Plastics having oxygen in their structures (PMMA, PA, PET, PU, and PC) enhanced the CO production. However, gasification of plastics having aromatic rings (PC, PET, and ABS) with sand as the bed material caused bed agglomeration and a severe coke buildup on an activated carbon bed. Dolomite as the fluidized bed material was found to be very effective in solving these operational problems.

Improving Fast Pyrolysis Bio-Oil Yield and Quality by Alkali Removal from Feedstock.

Alkali removal from forest residues, eucalyptus residues, and wheat straw was studied by water and dilute nitric acid leaching. Leaching parameters were optimized for each feedstock in laboratory-scale experiments. After the optimization of leaching on the laboratory scale, nitric acid-leached and untreated feedstocks were pyrolyzed in a bench-scale bubbling fluidized bed unit. In the case of eucalyptus residues and wheat straw, nitric acid leaching was found to increase the organic liquid yield compared to untreated feedstock. In addition, the sugar content of the fast pyrolysis bio-oils was increased, and the alkali content reduced. On the other hand, the pyrolysis experiments with acid-leached forest residues were unsuccessful due to the bed agglomeration. These problems are expected to be a result of the lack of catalytically active elements in biomass which enhance especially the cracking reactions of lignin. Finally, the results were demonstrated in the pilot-scale unit where nitric acid-leached oat straw was pyrolyzed with high organic liquid yield.