Laboratory-scale Spray Research Articles

Lactose hydrolyzed milk powder: Thermodynamic characterization of the drying process

ABSTRACTIndustrial production of lactose hydrolyzed milk powder (LHMP) remains challenging. Due to the presence of the monosaccharides glucose and galactose, lactose-free powders tend to suffer stickiness, caking, and browning during drying and storage. We sought to find ideal conditions spray dryer inlet air temperature (θair,in) and concentrated milk flow rate (mCM) for LHMP production. We tested θair,in settings of 115–160°C and mCM of 0.3–1.5 kg · h−1, and also applied mass and energetic balances. LHMP generally exhibited higher mass and energetic losses than the control (milk powder containing lactose), as a consequence of the relatively low dryability of LHMP. For a lab scale spray dryer, the ideal conditions settings for LHMP production were θair,in = 145 ± 2°C and mCM = 1.0 kg · h−1, taking into account the mass yield and energetic cost (kJ · kg−1 of powder) of the process. These ideal conditions are a potential tool for the industrial development of lactose-free dairy powders.

Inline method of droplet and particle size distribution analysis in dilute disperse systems

In the present article a measurement method of particle size distributions (PSD) in industrial installations which use a dispersed phase of low concentration (like spray dryers or spray scrubbers) is introduced. A new type of inline-measurement system has been developed and designed to work in spray drying conditions. A standard digital camera is used to record shadows of flowing particles inside the spray drying chamber. Collected images were analyzed by a newly developed software which recognizes particles only in the focus area and eliminates several types of artifacts. The constructed prototype of the PSD inline-analyzer was installed and used to monitor large laboratory scale spray dryer. All data collected by the designed system during the spray drying experiments were compared with data measured with an offline reference system to show accuracy of the new measurement technique.

648 Validation of micro-encapsulation method to protect probiotics and feed enzyme from rumen degradation

We hypothesize that supplementation of live yeast or feed enzyme (FE) may improve intestinal digestion and gut health, but with ruminants, the challenge is to deliver additive with high activity post-ruminally due to the highly proteolytic environment of the rumen. The objective of this study was to develop a micro-encapsulation method by measuring ruminal stability of encapsulated yeast and FE, and its release in the intestine. Live yeast and liquid FE were encapsulated using barley protein hordein and glutelin as capsule material. The barley protein powders were hydrated at pH 11.0 to form a 15% (w/v) solution. The pH was then adjusted to 7.0 followed by an immediate mixing with yeast or FE to form a coarse emulsion using a homogenizer. Microcapsules were then formed by passing the premixed emulsion through a microfluidizer system. The mixtures were spray-dried using a laboratory scale spray dryer. The ratio of capsule to additive was 1:1. The stability of encapsulated products in the rumen was measured as DM disappearance (DMD) in batch culture. Briefly, the encapsulated products (100 mg) were weighed into Ankom bags and placed in 100-mL serum bottles. Rumen inoculant (15 mL) from beef heifer and buffer solution (45 mL) was added to each bottle and incubated at 39°C for 0, 3, 6, 12 or 24 h. The residues in bags were digested in 1% pancreatin solution for 1 h to remove the encapsulation protection. Number of yeast colonies (cfu/g) was enumerated by spread plate method. Enzyme activity (EC 3.2.1.1) was assayed and expressed as μmol glucose equivalents/min/g FE. The DMD of encapsulated yeast were 3.1, 7.8, 9.1, 12.0 or 16.0%, and the cfu were 9.5, 2.2, 1.3, 1.1 and 0.6 (× 109), respectively, for residues after 0, 3, 6, 12, and 24 h of incubation. The DMD of encapsulated FE were 5.1, 31.4, 33.8, 40.6 or 43.6%, and the enzyme activity in residue were 41.9, 33.8, 19.7, 12.7 and 10.2 µmol/min/g, respectively, at 0, 3, 6, 12 and 24 h of incubation. The results showed that the encapsulated yeast products were stable in the rumen. Subsequently, the encapsulated yeast was released by digesting in pancreatin solution and cfu counts demonstrated over 90% survival rates. It suggests that this encapsulation technique is applicable as a novel method for delivering active yeast to the intestine. However, this technique may be not efficacy to protect liquid enzyme from rumen degradation.

Microwave Assisted Extraction of Avocado Oil from Avocado Skin and Encapsulation Using Spray Drying

The aim of this work was to extract the avocado oil from avocado skin. This oil was used to prepare the emulsion and encapsulation using spray drying. For the oil extraction, the efficiency of microwave assisted extraction (MAE) and soxhelt method was evaluated. The results indicated that MAE at 600 W for 15 min using 2-methyltetrahydrofuran gave the highest yield percentage. The emulsion preparation of avocado oil from MAE was prepared using the wall materials of maltodextrin and the Hi-Cap. The combinations of maltodextrin and Hi-Cap showed 100% stability for 24 hours, with no phase separation. The viscosity of the emulsions was reported at 11.00-13.00 mPa·s. The droplets mean diameter was between 2.05 to 2.08 µm. The microencapsulation of avocado oil was performed in a laboratory scale spray dryer. The encapsulation efficiency of three combinations of wall materials (F1 to F3) was valued of 60-80% which indicated that the increase on maltodextrin content, when combined to Hi-Cap, led to lower encapsulation efficiency. For particle characterization, the moisture content was 1.10-1.35 % and the bulk density was 0.35-0.37 g/cm3. Therefore, the proportion of wall materials had significant influence on the emulsion properties and on the encapsulation efficiency of avocado oil.

Application of Empirical Peleg Model to Study the Water Adsorption of Full Cream Milk in Drying Process

The ability of spray dryer in producing full cream milk at different inlet temperatures and the effectiveness of empirical model used in order to interpret the drying process data is evaluated in this study. In this study, a lab-scale spray dryer was used to dry full cream milk into powder with inlet temperature from 100 to 160°C with a constant pump speed 4rpm. Peleg empirical model was chosen in order to manipulate the drying data into the mathematical equation. This research was carry out specifically to determine the equilibrium moisture content of full cream milk powder at various inlet temperature and to evaluate the effectiveness of Peleg empirical model equation in order to describe the moisture sorption curves for full cream milk. There were two conditions set for this experiments; in the first condition (C1), further drying process of milk powder in the oven at 98°C to 100°C while the second condition (C2) is mixing the milk powder with different salt solutions like Magnesium Chloride (MgCl), Potassium Nitrite (KNO2), Sodium Nitrite (NaNO2) and Ammonium Sulfate ((NH4)2SO4). For C1, the optimum temperature were 160°C with equilibrium moisture content at 3.16 weight dry basis and slowest sorption rates (dM/dt) at 0.0743 weight dry basis/hr. For C2, the best temperature for the mixture of dry samples with MgCl is at 115°C with equilibrium moisture content and sorption rates is -78.079 weight dry basis and 0.01 weight dry basis/hr. The best temperature for the mixture of milk powder with KNO2 is also at 115°C with equilibrium moisture content and sorption rates at -83.9645 weight dry basis and 0.0008 weight dry basis/hr respectively. For mixture of dry samples with NaNO2, the best temperature is 160°C with equilibrium moisture content and sorption rates at 84.1306 weight dry basis and 0.0013 weight dry basis/hr respectively. Lastly, the mixture of dry samples with ((NH4)2SO4 where the best temperature is at 115°C with equilibrium moisture content -83.8778 weight dry basis and sorption rates at 0.0021 weight dry basis/hr. The best temperature selected best on the lowest moisture content formed and also the slowest sorption rates.

Spray-dried adjunct cultures of autochthonous non-starter lactic acid bacteria

Spray-drying of lactic cultures provides direct-to-vat starters, which facilitate their commercialization and use. However, this process may alter the metabolic activity and deteriorate technological features. In this work, we assessed the influence of spray-drying on the survival and aroma production of two strains of mesophilic lactobacilli: Lactobacillus paracasei 90 and Lactobacillus plantarum 91, which have already been characterized as good adjunct cultures. The spray-drying was carried out using a laboratory scale spray and the dried cultures were monitored during the storage for the survival rate. The dried cultures were applied to two cheese models: sterile cheese extract and miniature soft cheese. The influence on the carbohydrate metabolism and the production of organic acids and volatile compounds was determined. Both strains retained high levels of viable counts in the powder after drying and during the storage at 5°C for twelve months. In addition, they also remained at high level in both cheese models during incubation or ripening. Similar profiles of carbohydrate fermentation and bioformation of volatile compounds were observed in the cheese extracts for each of the strains when tested as both fresh and dried cultures. In addition, the ability of Lb. paracasei 90 to increase the production of acetoin and diacetyl remarkably in cheese models was also confirmed for the spray-dried culture.

Validation of Various Antimicrobial Interventions for Use in a Bone Dust Cabinet in a Commercial Beef Harvest Facility

ObjectivesThe objective of this study was to evaluate the efficacy of 3 antimicrobial spray interventions (peroxyacetic acid, PAA; lactic acid, LA; lactic/citric acid blend, LCA) in reducing inoculated populations of Shiga toxin-producing Escherichia coli (STEC) on pre-rigor beef tissue. A secondary objective was to validate E. coli biotype I to serve as surrogates for STEC.Materials and MethodsThe efficacy of each intervention was assessed using a 14-strain mixture of rifampicin-resistant STEC, comprised of 2 strains of E. coli O157:H7 and 2 strains each of E. coli serogroups O26, O45, O103, O111, O121, and O145. In addition, this study served to validate the utility for a non-pathogenic 5-strain mixture of rifampicin-resistant E. coli biotype I to serve as surrogates for the aforementioned STEC mixture. For 3 sampling days, 90 tissue samples from pre-rigor plate subprimals were obtained from beef carcasses immediately following slaughter. The tissue samples were evenly split into 2 inoculation groups (n = 45 samples/group, 15/group/d): i) STEC, or ii) surrogate. Within each inoculation group, tissue samples were randomly assigned to 1 of 9 treatments: i) 200 ppm PAA; ii) 1% LCA; iii) 1.5% LCA; iv) 2.5% LCA; v) 5% LA; vi) 8% LA; vii) 10% LA; viii) potable water; or ix) untreated control. The external fat surface of pre-rigor tissues samples was spot inoculated (5 to 6 log CFU/cm2) with 100 μL of the STEC or surrogate inoculum and was spread over a 50 cm2 area using a sterile plastic spreader. Within each inoculation group, treatments were applied using a custom-built, laboratory-scale spray cabinet (0.53 lpm, 137.9 kPA over 8 floodjet spray nozzles). Tissue surfaces were sampled approximately 10 min after spray-treatment application, using sponges hydrated with D/E neutralizing broth, and analyzed for surviving STEC and surrogate populations on tryptic soy agar supplemented with rifampicin (100 µg/ml). This experiment was conducted as a randomized complete block design. Data were evaluated using the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC). To compare surviving populations of the surrogates and STEC, data were analyzed using the MIXED Procedure in SAS with microbial population of the untreated control samples used as a covariate to adjust least-squares means to a common pre-treatment inocluated plate count.ResultsWhen applied as a spray treatment to pre-rigor beef tissue, LA applied as a 10% solution was more (P < 0.05) effective at reducing STEC and surrogate populations than water, PAA, 1, 1.5 or 2.5% LCA, and 5 and 8% LA (Table 1). Additionally, the 5, 8, and 10% LA treatments were more (P < 0.05) effective at reducing both inoculum types than water, PAA, or 1, 1.5 or 2.5% LCA. No differences (P ≥ 0.05) in surviving STEC populations were observed for tissue samples treated with PAA, 1.5% LCA or 2.5% LCA. Pairwise comparisons indicated surviving STEC and surrogate populations did not differ (P ≥ 0.05).ConclusionWhen all treatments were compared, LA, at 10%, was found to have the greatest effect against STEC populations. As evidenced by similar surviving populations of STEC and surrogate populations, the 5-strain, non-pathogenic E. coli would effectively serve as a surrogate inoculum for the 14-strain STEC cocktail used in this study.

Preparation and Characterization of Magnetic Nano-in-Microparticles for Pulmonary Delivery.

The purpose of this chapter is to detail the formulation and characterization of a magnetically-targeted drug delivery vehicle, termed nano-in-microparticles (NIMs), for pulmonary drug delivery. Currently, chemotherapeutics and antibiotics are delivered systemically and result in whole body side-effects. NIMs are formulated with superparamagnetic iron oxide nanoparticles, termed SPIONs, making these particles targetable to specific lung regions using a strong external magnet. Additionally, these particles can be formulated to contain any drug or therapeutic agent, such that a therapeutic dose can be delivered to a specific tissue location using the SPIONs-magnet interaction. Finally, these particles are in the appropriate size range for pulmonary delivery, making NIMs therapeutics feasibly inhalable.To generate these particles a solution containing lactose, SPIONs, and a microsphere dye (used as a drug surrogate) is spray-dried using a laboratory-scale spray dryer. The resulting dry powder microparticles (NIMs) can be characterized for their size and morphological properties by various techniques that are presented in this chapter.The utility of NIMs as a magneticfield-dependent targeting delivery platform in an in vivo mouse model has been demonstrated, and a protocol detailing the intratracheal delivery of NIMs dry powder is included as a separate chapter in this book.

A novel rate of the reaction between NaOH with CO2 at low temperature in spray dryer

Abstract Carbon dioxide (CO 2 ) is an influential greenhouse gas that has a significant impact on global warming partly. Nowadays, many techniques are available to control and remove CO 2 in different chemical processes. Since the spray dryer has high removal efficiency rate, a laboratory-scale spray dryer is used to absorb carbon dioxide from air in aqueous solution of NaOH. In the present study, the impact of NaOH concentration, operating temperature and nozzle diameter on removal efficiency of CO 2 is explored through experimental study. Moreover, the reaction kinetic of NaOH with CO 2 is studied over the temperature range of 50–100 °C in a laboratory-scale spray dryer absorber. In the present contribution, a simple reaction rate equation is proposed that shows the lowest deviation from the experimental data with error less than 2%.

Spray Drying as a Processing Technique for Syndiotactic Polystyrene to Powder Form for Part Manufacturing Through Selective Laser Sintering

Selective laser sintering (SLS) is a rapidly expanding field of the three-dimensional printing concept. One stumbling block in the evolution of the technique is the limited range of materials available for processing with SLS making the application window small. This article aims at identifying syndiotactic polystyrene (sPS) as a promising material. sPS pellets were processed into powder form with a lab-scale spray dryer with vibrating nozzle. This technique is the focus of this scope as it almost eliminates the agglomeration phenomenon often encountered with the use of solution-based processing techniques. Microspheres obtained were characterized in shape and size by scanning electron microscopy and evaluation of the particle size distribution. The effect the processing technique imparts on the intrinsic properties of the material was examined by differential scanning calorimetry analysis.

Spray dried SiO2 WO3/TiO2 and SiO2 vanadium pyrophosphate core-shell catalysts

Commercial catalytic gas-solid fluidized reactors operate best with a wide particle size distribution (PSD) centered around 70μm. Spray drying micro-sized powders with binders—colloidal silica, for example—provides the attrition resistance required to withstand the mechanical stresses inherent in these reactors. Commercial dryers 8m in diameter treat slurries at a rate of 1000kgh−1 and particle residence times are greater than 1min. Residence times in laboratory scale spray dryers are an order of magnitude lower. Droplets forming at the nozzle must be smaller in laboratory units so that they dry, consequently the average particle size is smaller. Here, we spray dried WO3/TiO2 and vanadium pyrophosphate catalysts with a combination of colloidal silica, polyvinyl alcohol and H3PO4 at 180° C and 245° C. The colloidal silica formed a 2μm shell at the outer surface of the particle regardless of the spray drying temperature. However, the lower temperature was insufficient to dry all the droplets formed at the nozzle and so particles agglomerated. Particle diameters are higher with high slurry concentrations and low atomization pressures, but the nozzle blocks when the slurry concentration is greater than 25%. Increasing the nozzle pressure to maintain the nozzle clear produces smaller droplets.

Microencapsulation of lipid materials by spray drying and properties of products

AbstractLipophilic bioactive materials, such as carotenoids, exhibit various health benefits. To enhance their stability and application in food and pharmaceutical industries, feasibility of microencapsulating these bioactive materials by spray drying was investigated. High‐ and low‐energy emulsification methods were compared at various emulsion compositions and their effects on emulsion stability were characterized. High‐energy method was preferred for safety concerns, as it was able to produce fine emulsions (davg &lt; 400 nm) at relatively low surfactant‐to‐oil ratio. The formed infeed emulsions, with MCT oil as core material, gelatin as wall material and primary emulsifier and Tween 80 as secondary emulsifier, were then spray dried using a lab scale spray dryer (Büchi B‐290). Operating conditions were optimized and results demonstrated that spray drying technology could be applied to transform stable infeed emulsions (containing bioactive materials) into microcapsules with desired properties (e.g., low moisture content (5.5–7% (d.b.)), relatively narrow size distribution (d50 between 9.8 and 10.8 μm), and high encapsulation efficiency (around 90%)). So, it is feasible to use this emulsion‐based system to microencapsulate bioactive materials by spray drying.Practical applicationLipophilic bioactive elements are highly susceptible to adverse environment conditions. To overcome these problems, feasibility of microencapsulating these bioactive materials by spray drying was investigated in the present study. A high‐energy method was compared with a low‐energy method in order to find an appropriate emulsification method. The formed infeed emulsion was then spray dried to determine optimum operating conditions. This research should be useful for identifying the most appropriate operating conditions for lipophilic bioactive materials microencapsulation for industrial application especially in food and pharmaceutical industries. Meanwhile, it also provides a possible reference for other scientists and researchers.

The use of a plug-flow model for scaling-up of spray drying bioactive orange peel extracts

Abstract The spray drying of orange peel extracts was scaled up from a laboratory-scale spray dryer to a pilot-scale spray dryer using two methods to predict the parameters of the spray-drying process. The mass and energy balance model predicted the outlet gas temperature, absolute humidity and the final moisture content of the particles with 5%, 2% and 74% errors, respectively whereas, the plug-flow model successfully predicted these parameters with Industrial relevance Peels and seeds of citrus fruits, such as oranges, contain bioactive phenolic compounds that have demonstrated cancer-inhibition properties. However, due to their bitterness, they are not consumed and are considered to be waste material. The compounds can be extracted and turned into concentrated powder supplements. In powder form, these compounds can be easily incorporated in controlled and concentrated dosages into food formulae in order to create functional foods while masking the unpleasant taste. However, due to the heat sensitivity of these compounds, the minimum amount of heat treatment is required in the process. Spray drying, which is one of the fastest drying techniques available, can be used to convert these extracts into powders. However, spray drying these extracts is very challenging due to the presence of large amounts of sugars that cause stickiness and product loss during the process. In general, adding significant amounts of carriers to sugar-rich foods to overcome their stickiness during spray drying has been used in industry, compromising the purity of the final products. Moreover, in order to mass produce the powders, the process needs to be scaled-up. However, spray drying is extremely difficult to scale up using dimensional analysis (Oakley, 1994; Zlokarnik, 2003b). Computational fluid dynamic (CFD) simulations have been suggested as a powerful tool in this scale up of spray drying, but they are very time consuming. Therefore, if simpler models that do not require CFD simulations can adequately predict the process parameters, they can be used as fast estimation techniques for scale up. The results from this study guide the use of a plug-flow model for scaling up the process of spray drying orange-peel extracts while keeping an acceptable quality for the final product.

Spray drying bioactive orange-peel extracts produced by Soxhlet extraction: Use of WPI, antioxidant activity and moisture sorption isotherms

Spray drying of orange peel extracts was performed using a laboratory-scale spray dryer in order to assess the best operating conditions to be used in a subsequent scale-up process. Addition of whey protein isolate (WPI) to the liquid feed enhanced the yield of the process significantly from 30 ± 10% to 63 ± 3%. The moisture sorption isotherms of the powders were also determined at 30 °C, 40 °C and 50 °C and fitted by the Guggenheim-Andersen-de Boer (GAB) equation. The average net isosteric heat of sorption for the powders was determined using the Clausius–Clapeyron equation to be 70.5 kJ/kg. The total phenolic content (TPC) and the free radical scavenging capacity (SC50) of the powders were retained by 95 ± 5% and 95 ± 15%, respectively, during small-scale spray drying at an inlet air temperature of 150 °C and a corresponding outlet temperature of 70 ± 3 °C. Therefore, the best operating conditions for scale-up were suggested to be an inlet air temperature of 150 °C, a maximum allowable outlet temperature of 80 °C and a maximum allowable relative humidity for the exhaust air of 15%, while using a liquid feed containing 7.5% (w/w), dry basis WPI.

Investigation of suitable spray drying conditions for sugarcane juice powder production with an energy consumption study

Sugarcane juice was spray-dried under various conditions to determine the most suitable drying conditions for the manufacture of sugarcane juice powder. Initially, fresh, 30°Brix and 50°Brix sugarcane juice samples were dried in a laboratory-scale spray dryer at an air-drying temperature between 130 °C and 170 °C using maltodextrin, Arabic gum and dietary fiber as drying aids. It appeared that sugarcane juice should be concentrated under vacuum to 30°Brix and added with at least 15% maltodextrin before drying at 170 °C in order to obtain dried powder product with a low drying cost. After conducting the experiments in the laboratory, sugarcane juice powders were produced in a factory using an industrial-scale spray dryer under five drying conditions. It was found that the energy cost of industrial-scale production of sugarcane juice powder ranged between 0.77 USD and 2.06 USD per kg of powder. According to the results of the industrial-scale experiments, the sugarcane juice powder should be produced using vacuum evaporation of the sugarcane juice to 30°Brix prior to adding maltodextrin at 30% by weight and then spray drying at 190 °C.

Spray drying of lipid-based systems loaded with Camellia sinensis polyphenols

In this work, spray-dried lipid systems based on soy phosphatidylcholine, cholesterol and lauroyl polyoxylglycerides for entrapping Green tea polyphenols were produced. The aim was to study the effects of the encapsulating composition and spray drying conditions on the system performance and physicochemical product properties. The spray dryer powder production yield falls around 50.7 ± 2.8%, which is typical for lab scale spray dryers. Wrinkled and rounded particles, with low surface porosities were generated, independent of the drying carriers (trehalose or lactose) used. The product showed high encapsulation efficiency of Green tea polyphenols, which was promptly redispersible in water. It presented low density, and good compressive and flow properties. The results herein reported confirm the feasibility of the entrapment of Green tea polyphenols in lipid-based compositions by spray drying in presence of the drying carriers evaluated. The spray-dried microparticles show high potential to be used as additive in food, nutraceutical and pharmaceutical products.

Roles of particle size on physical and mechanical properties of dairy model solids

Lactose/milk protein isolate (MPI) solids systems were prepared by laboratory-scale spray dryer (defined as S-lactose/MPI solids systems) and pilot-scale spray dryer (defined as L-lactose/MPI solids systems). Particles of L-lactose/MPI solids systems had more rounded shape, and smoother surface than those of S-lactose/MPI solids systems. Water sorption study showed S-lactose/MPI solids systems sorbed 5–30% larger amount of water than L-lactose/MPI solids systems after equilibrated at different water activities (0.11 aw–0.44 aw). Besides, comparing the samples with same composition, dairy solids with small size particles showed higher steady water content at the end of lactose crystallisation. Moreover, S-lactose/MPI solids systems showed lower glass transition temperature (Tg) values than L-lactose/MPI solids systems after equilibration at 0.11 aw, 0.23 aw and 0.33 aw, which might be due to the higher water content of S-lactose/MPI solids systems. The study of mechanical properties indicated the stiffness of S-lactose/MPI solids systems was higher than that of L-lactose/MPI solids systems at 0.23 aw and 0.33 aw when temperature was below Tg values. Water plasticization showed stronger effect on relaxation process of dairy solids with smaller size particles.

PROCESS SIMULATION OF PINEAPPLE JUICE SPRAY DRYING

Pineapple juice is one of the known natural sources of bromelain, a bioactive compound beneficial to health. The dried powder has potential commercial value and is a convenient source of the juice drink. The quality of spray dried pineapple juice is dependent on the powder moisture content. Spray dried pineapple powders with low moisture contents were produced in a lab-scale spray dryer in this study. Powder production of 25% of total solids were obtained by use of DE6 maltodextrin to solids ratio of 0.41:0.59. A heat and mass transfer model of the spray drying process was implemented in Matlab and solved to determine its predictive utility. The simulation results showed agreement with experimental data at high inlet air temperatures but widely diverged at other air temperatures. The error size in predicted product moisture varied from 73% at 165 oC to almost zero at 185 oC while that for the predicted exit air temperatures varied from about 38% to zero over the same temperature range. Accuracy can be improved if transient heat effects, and sub models for the feed drying are included in the model.

Electrolyzed Water Spray Scrubber for Removing Ammonia from Air

<abstract> Ammonia (NH₃) emissions from animal feeding operations (AFOs) are the source of a number of environmental issues. Wet spray scrubbers using non-acidic solutions might be a new approach for NH₃ mitigation from AFOs. A lab-scale spray scrubber was built to clean 0.024 m³ s^-1 of an NH₃/air mixture with an average NH₃ concentration of 20 ppmv. Three variables including contact time, nozzle type, and scrubbing solution were investigated to evaluate their effects on the ammonia removal efficiency of the scrubber. The contact times were set to 0.3, 0.6, and 0.9 s, which were achieved by changing the elevation of the spray nozzle. Two types of spray nozzles were studied. The nozzles had full-cone spray patterns with different spray angles and different droplet sizes. Reverse osmosis (RO) NH₃ gas from air. The maximum removal efficiency of 56% was achieved with the ₃ mass ratios lower than 7.6 in order to avoid N₂, Cl₂, and NH₃ gas losses from the scrubbing solution.

Effect of spray dryer settings on the morphology of illite clay granules

&lt;p class="R-AbstractKeywords"&gt;&lt;span lang="X-NONE"&gt;Spray drying is an effective and common method for powder drying, e.g. clay. The morphology and properties of spray dried granules depend on properties of slurry and operational conditions of spray dryer. The aim of this study was to investigate the effect of spray dryer settings on the morphology of illite clay granules. &lt;/span&gt;&lt;/p&gt;&lt;p class="R-AbstractKeywords"&gt;&lt;span lang="X-NONE"&gt;Laboratory scale spray dryer was used. Operational conditions: inlet temperature 190-220˚C, outlet temperature 70-96˚C, spray dispersion is obtained using two-fluid nozzle where the slurry feed was varied from 4.5 to 15 ml/min and gas pressure 15-40 mm. Slurry was prepared from clay fraction under 2 µm without additives. Latvian illite clay from Iecava, Pavāri and Laža deposits was studied. Slurries with concentration 1, 8 and 15 mass% was used.The size and morphology was investigated by scanning electron microscopy, surface area and porosity by liquid nitrogen sorption.&lt;/span&gt;&lt;/p&gt;&lt;p class="R-AbstractKeywords"&gt;&lt;span lang="X-NONE"&gt;All obtained granules irrespective of &lt;/span&gt;&lt;span lang="X-NONE"&gt;spray dryer settings&lt;/span&gt;&lt;span lang="X-NONE"&gt; were well-rounded and dense without large pores or holes, however the surface was rough. The mean diameter of granules was in range of 2.6-5.4 µm, depending on slurry feed rate. The surface area of produced granules mostly depended on clay composition and was in a range of 70-92 m2/g. Inlet temperature in a range of 190-220 °C was found to be appropriate to produce well dried clay granules (moisture content &amp;lt;10 wt%). &lt;/span&gt;&lt;/p&gt;