Characterization of a Spray Drying System for Soymilk

ABSTRACT

Soymilk slurries were spray dried at various combinations of inlet air temperature (1255. 265, and 275°C), feed rate (0.38 and 0.57 Lpm), and atomizer speed (119,300 and 26,800 rpm). Monitored dryer parameters included dry and wet bulb temperaturea of ambient and exhaust air, drying chamber's inlet and outlet air temperatures, product and feed temperatures, velocity pressure at exhaust pipe, atomizer speed, and feed rate. Weather data was included in the analysis.

Collected data was used to estimate the state of the outlet air using psychrometrics and assuming adiabatic saturation. Equations to predict outlet and product temperatures were developed. Average thermal and eveporative efficiencies were 65.9 and 78.4%. respectively.     

Spray Drying Performance of a Laboratory Spray Dryer for Tomato Powder Preparation

This work investigates the performance of a spray dryer for tomato powder preparation by spray drying of tomato pulp. Samples of tomato pulp with a 14% constant total solids concentration were used, and a pilot scale spray dryer (Buchi, B-191) with cocurrent operation and a two-fluid nozzle atomizer was employed for the spray drying process. Twenty-four different experiments were conducted keeping constant the feed rate, the feed temperature, and the atomizer pressure, and varying the compressed air flow rate, the flow rate of drying rate, and the air inlet temperature. In each experiment the air outlet temperature was recorded. Data for the residue remaining in the chamber and cyclone walls was gathered and two types of efficiencies were calculated as an indication of the spray dryer performance. Analysis of experimental data yielded correlations between residue accumulation and the variable operating conditions. The same operating parameters had a great influence on the air outlet temperature whereas temperature deviations were observed comparing measured air outlet temperatures with corresponding outlet adiabatic saturation temperatures.     

Spray Drying Performance of a Laboratory Spray Dryer for Tomato Powder Preparation

Abstract

This work investigates the performance of a spray dryer for tomato powder preparation by spray drying of tomato pulp. Samples of tomato pulp with a 14% constant total solids concentration were used, and a pilot scale spray dryer (Buchi, B-191) with cocurrent operation and a two-fluid nozzle atomizer was employed for the spray drying process. Twenty-four different experiments were conducted keeping constant the feed rate, the feed temperature, and the atomizer pressure, and varying the compressed air flow rate, the flow rate of drying rate, and the air inlet temperature. In each experiment the air outlet temperature was recorded. Data for the residue remaining in the chamber and cyclone walls was gathered and two types of efficiencies were calculated as an indication of the spray dryer performance. Analysis of experimental data yielded correlations between residue accumulation and the variable operating conditions. The same operating parameters had a great influence on the air outlet temperature whereas temperature deviations were observed comparing measured air outlet temperatures with corresponding outlet adiabatic saturation temperatures.     

Spray Drying of Mannitol as a Drug Carrier—The Impact of Process Parameters on Product Properties

Powders intended for the use in dry powder inhalers have to fulfill specific product properties, which must be closely controlled in order to ensure reproducible and efficient dosing. Spray drying is an ideal technique for the preparation of such powders for several reasons. The aim of this work was to investigate the influence of spray-drying process parameters on relevant product properties, namely, surface topography, size, breaking strength, and polymorphism of mannitol carrier particles intended for the use in dry powder inhalers. In order to address this question, a full-factorial design with four factors at two levels was used. The four factors were feed concentration (10 and 20% [w/w]), gas heater temperature (170 and 190°C), feed rate (10 and 20 L/h), and atomizer rotation speed (6,300 and 8,100 rpm). The liquid spray was carefully analyzed to better understand the dependence of the particle size of the final product on the former droplet size. High gas heater temperatures and low feed rates, corresponding to high outlet temperatures of the dryer (96–98°C), led to smoother particles with surfaces consisting of smaller crystals compared to those achieved at low outlet temperatures (74–75°C), due to lower gas heater temperatures and higher feed rates. A high solution concentration of the feed also resulted in the formation of comparably rougher surfaces than a low feed concentration. Spray-dried particles showed a volume-weighted mean particle size of 71.4–90.0 µm and narrow particle size distributions. The mean particle size was influenced by the atomizer rotation speed and feed concentration. Higher rotation speeds and lower feed concentrations resulted in smaller particles. Breaking strength of the dried particles was significantly influenced by gas heater temperature and feed rate. High gas heater temperatures increased the breaking strength, whereas high feed rates decreased it. No influence of the process parameters on the polymorphism was observed. All products were crystalline, consisting of at least 96.9% of mannitol crystal modification I.     

MANUFACTURING PARAMETERS AND QUALITY CHARACTERISTICS OF SPRAY DRIED JAMEED

Spray drying of jameed - a dried fermented dairy product, is investigated. The study covers the effects of the operating variables upon the physical and chemical characteristics of the dried product. The investigated variables were: feed total solids, feed flow rate, inlet air temperature, air flow rate and atomizer pressure. The product characteristics measured were: total solids, bulk density, average particle size, wettability, dipersibility, color, ash content, salt content, fat content and pH. Best overall results were obtained for a feed total solids of 17%, feed flow rate of 36.5 ml/min, inlet air temperature of 100 /C, air flow rate of 632 cm₃/s, and atomizer pressure of 1.5 bar.     

MANUFACTURING PARAMETERS AND QUALITY CHARACTERISTICS OF SPRAY DRIED JAMEED

ABSTRACT

Spray drying of jameed - a dried fermented dairy product, is investigated. The study covers the effects of the operating variables upon the physical and chemical characteristics of the dried product. The investigated variables were: feed total solids, feed flow rate, inlet air temperature, air flow rate and atomizer pressure. The product characteristics measured were: total solids, bulk density, average particle size, wettability, dipersibility, color, ash content, salt content, fat content and pH. Best overall results were obtained for a feed total solids of 17%, feed flow rate of 36.5 ml/min, inlet air temperature of 100 /C, air flow rate of 632 cm₃/s, and atomizer pressure of 1.5 bar.     

An Experimental Investigation of the Wall Deposition of Milk Powder in a Pilot-Scale Spray Dryer

A pilot-scale, co-current spray dryer has been used to investigate the effect of varying the swirl vane angle for the inlet air, inlet air temperature and liquid feed flowrate on the wall deposition flux of skim milk powder. The spray dryer was a cylinder-on-cone unit with a diameter of 0.8 m and a height of 2 m. It was fitted with adjustable swirl vanes surrounding a Delavan GA1 two-fluid atomizer. Swirl vane angles of 0, 25, and 30°, inlet air temperatures of 170, 200, and 230°C and feed flowrates of 1.4, 1.6 and 1.8 kg h^-1 were used. Inlet air swirl was found to significantly influence the wall deposition flux, with the highest swirl vane angle of 30° giving rise to the largest wall deposition flux. The difference between the particle and sticky-point temperatures of the skim milk powder was also found to be important in influencing the wall deposition flux. The wall deposition flux was the highest, at 16 g m^-2 h^-1, when the outlet particle temperature was furthest above the sticky-point temperature, and this occurred at the lowest value of the inlet air temperature (170°C) and highest product moisture content. No significant effect on the wall deposition flux was evident when using a nonstick food grade material (nylon), adhesive tape or stainless steel as the surface materials for the wall deposition tests. Therefore, it is likely that cohesion occurs at a similar rate to adhesion in the wall deposition of milk powder. Grounding the spray dryer also did not have a significant effect on the wall deposition flux. Relating the wall deposition flux to the sticky-point curve in this way suggests that the same trends (increased wall deposition fluxes above the sticky-point curve) may apply for other materials as well.     

SPRAY DRYING DYNAMIC MODELING WITH A MECHANISTIC MODEL

In this work we suggest the dynamic modeling of a spray dryer considered as a series of well-stirred dryers. That is, a series of dryers in which the output variables are equal to the state variables. The state equations were obtained from the heat and water mass balances in product and air. Additionally, heat and water mass balances in interface jointly with water equilibrium relation between product and air were considered. A pilot spray dryer was modeled assuming one, two, five and 20 well stirred steps. Low-fat milk with 10-20% of solids was dried at different inlet air temperatures (120-160°C), air flow rate of 0.19 kg dry air s^-1 and different feed rates (1.4 - 4.2 × 10^-4 kg dry solids s^-1). Stationary result showed that the model predicts the experimental air outlet temperature, at different inlet conditions with a maximum deviation of 6°C. The dynamic simulation reproduce the experimental one with moderate accuracy. Experimental dynamic showed that the pilot plant spray dryer has a well-stirred process behavior. The model represents a method for estimate outlet product moisture as function of the outlet air temperature. This has application for automatic control because there is not an easy way to measure on-line measure the outlet product moisture content.     

Spray Drying and Agglomeration of Instant Bayberry Powder

Optimum technology of spray-dried bayberry powder was studied using D-optimal experimental design. The operating conditions were varied within the following ranges: inlet air temperature 140–160°C, outlet air temperature 65–85°C, maltodextrin DE values 12 and 19, and feed concentrations of 7–17°B. The spray-dried bayberry powder was analyzed for moisture content and color. Moisture content of spray-dried powder was determined mainly by the inlet and outlet air temperatures, DE value, and the feed concentration. The inlet and outlet temperature had important effects on powder color. Finally, instant bayberry powder for beverages was produced by agglomeration of the spray-dried product.     

Spray Drying and Agglomeration of Instant Bayberry Powder

Optimum technology of spray-dried bayberry powder was studied using D-optimal experimental design. The operating conditions were varied within the following ranges: inlet air temperature 140-160°C, outlet air temperature 65-85°C, maltodextrin DE values 12 and 19, and feed concentrations of 7-17°B. The spray-dried bayberry powder was analyzed for moisture content and color. Moisture content of spray-dried powder was determined mainly by the inlet and outlet air temperatures, DE value, and the feed concentration. The inlet and outlet temperature had important effects on powder color. Finally, instant bayberry powder for beverages was produced by agglomeration of the spray-dried product.     

SPRAY DRYING DYNAMIC MODELING WITH A MECHANISTIC MODEL

ABSTRACT

In this work we suggest the dynamic modeling of a spray dryer considered as a series of well-stirred dryers. That is, a series of dryers in which the output variables are equal to the state variables. The state equations were obtained from the heat and water mass balances in product and air. Additionally, heat and water mass balances in interface jointly with water equilibrium relation between product and air were considered. A pilot spray dryer was modeled assuming one, two, five and 20 well stirred steps. Low-fat milk with 10–20% of solids was dried at different inlet air temperatures (120–160°C), air flow rate of 0.19 kg dry air s^?1 and different feed rates (1.4 ? 4.2 × 10^?4 kg dry solids s^?1). Stationary result showed that the model predicts the experimental air outlet temperature, at different inlet conditions with a maximum deviation of 6°C. The dynamic simulation reproduce the experimental one with moderate accuracy. Experimental dynamic showed that the pilot plant spray dryer has a well-stirred process behavior. The model represents a method for estimate outlet product moisture as function of the outlet air temperature. This has application for automatic control because there is not an easy way to measure on-line measure the outlet product moisture content.     

Optimization of Process Parameters for Spray Drying of Fermented Soy Milk

Generally used as an inexpensive source of high-quality protein with many other health-promoting properties, soy milk offers an interesting alternative when fermented. Fermentation with lactic acid bacteria brings about the value addition to soy milk, making a nutritious probiotic food product. Dehydration helps to achieve longer shelf life and easier transportation and storage, enabling wider distribution of the product. The present work pertains to optimization of process parameters for spray drying of fermented soy milk using response surface methodology (RSM). The process parameters studied include inlet air temperature, aspirator speed (air flow rate), feed flow rate, and atomization pressure. The experiments were designed using the central composite design tool. Residual moisture content was found to be low at higher inlet air temperature, lower feed flow rate, higher atomization pressure, and higher air flow rate. Porosity reduced with increased atomization pressure. Higher product yield was obtained at high air flow rate and low feed flow rate. The increase in the atomization pressure increases the cohesiveness between particles, resulting in reduced flowability. An increase in the inlet air temperature greatly reduces the viability and the isoflavone aglycone content in the product. Protein denaturation during the process was found to reduce the product solubility.     

Spray Drying of Chicken Meat Protein Hydrolysate: Influence of Process Conditions on Powder Property and Dryer Performance

The influence of operational conditions of a spray dryer on powder properties and equipment performance during spray drying of chicken meat hydrolysate was evaluated by a central composite rotatable design. The independent variables were inlet air temperature (120 to 200°C) and feed flow (0.1 to 0.38 kg/h). Spray dryer performance was assessed through estimation of product recovery, outlet air temperature, thermal efficiency, and energy on the dryer, obtained by mass and heat balance in the dryer system. Powder property was characterized in respect to antioxidant activity. The stable free radical diphenylpicrylhydrazyl (DPPH) was used to estimate the antioxidant activity of protein hydrolysate powder. This response varied from 38.7 to 59.4% and was only affected by inlet air temperature. Moreover, the results demonstrate a significant effect of the processing conditions on dryer performance. The increase of feed flow results in higher thermal efficiency and lower energy on dryer. Higher product recovery values were obtained at lower inlet air temperature and feed flow.     

Effects of Drying Parameters on Heat Transfer during Drying of Fermented Ground Cassava in a Rotary Dryer

The effects of drying parameters on heat transfer during drying of fermented ground cassava in a rotary dryer were studied. The fermented ground cassava was dried in a bench-scale rotary dryer at different inlet air temperatures, inlet air velocities, relative humidities, feed rates, drum drive speeds, and feed drive speeds. It is shown that inlet air temperature, inlet air velocity, and feed rate have significant effects on the specific heat transfer coefficient and heat load in the material. Models that predict the specific heat transfer coefficient as a function of inlet air temperature and inlet air velocity and the heat load as a function of inlet air temperature, inlet air velocity, and feed rate are also presented. Predictions of the models are compared with experimental data and good agreement is obtained.     

COMBINED CONVECTIVE AND INFRARED DRYING OF A CAPILLARP POROUS BODY

Abstract

This work investigates the effect of spray drying conditions on some properties of tomato powder prepared by spray drying of tomato pulp. A pilot scale spray dryer (Buchi, B-191) with cocurrent regime and a two-fluid nozzle atomizer was employed. Sixty-four different experiments were conducted keeping constant the feed rate, the feed temperature, and the atomizer pressure, and varying the compressed air flow rate, the flow rate of drying air, and the air inlet temperature. Tomato powders were analyzed for moisture, solubility, density (bulk and packed), and hygroscopicity. Analysis of experimental data yielded correlations between powder properties and the above-mentioned variable operating conditions. Regression analysis was used to fit a full second order polynomial, reduced second order polynomials and linear models to the data of each of the properties evaluated. F values for all reduced and linear models with an R ² ≥ 0.70 were calculated to determine if the models could be used in place of full second order polynomials.     

不同干燥方式制备白果粉的性能比较

天然产物白果会因干燥方式的不同,而使得干燥白果粉性能有所差别。本研究分别采用喷雾干燥(SP)与真空冷冻干燥(FD)对白果浆进行干燥处理。然后对两种干燥白果粉的性能(含水量、颗粒度、色泽、蛋白质质量分数)进行对比来比较各自的优越性。喷雾干燥采用参数:风量120 m³/h,进料浓度8%(质量分数),进气温度205℃,出气温度100℃,雾化器转速32000 r/min。真空冷冻干燥先在-40℃下预冻4h后,再在真空度300 Pa下-50℃低温干燥48 h。结果发现含水量SP相似文献   

Energy requirements and production cost of the spray drying process of cheese whey

The influence of spray drying conditions on the energy required, production cost, and physicochemical characteristics of cheese whey was researched. The factors investigated were the inlet air temperature (180–220°C), outlet air temperature (80–100°C), and silica and maltodextrin (DE-10) as additives at 2 and 5% (w/w), respectively. Analysis of variance revealed that the inlet and outlet air temperatures, and the addition of additives had significant effects (p?T_inlet of 180°C, T_outlet of 80°C, and the addition of 5% additive material. Under these conditions, 0.2165?kg/h of dried product was obtained, with a moisture content of 2.08% and water activity of 0.125, and the product cost was $17.06?kg with an energy consumption of 2.0490?kW?·?h/kg of dry product.     

Continuous Drying of Slurry in a Jet Spouted Bed

he performance of a laboratory scale jet spouted bed (JSB) for drying rice flour slurry was studied. The bed consisted of ceramic balls (5028 mm diameter) and the rice flour slurry was sprayed onto the moving particle surface near the inlet part. All the experiments were carried out at the jet spouting regime. This regime has high bed void fraction and violent movement and collision of bed particles. As a result, the dried product layer is attrited from particle surface as a fine powder and entrained from the bed by the spouting air. The experimental result were presented to show the effects of static bed height, inlet air flow rate and temperature, and feed concentration and flow rate on the outlet air temperature, thernal efficiency, and mean particle size and moisture content of the product. Asimple mathematical model, which is based on the conservation of mass and energy equations, was developed. Predicted results agreed well with those obtained from the experiment.     

An Investigation and Quantitative Assessment of Particle Shape in Milk Powders from a Laboratory-Scale Spray Dryer

Seven samples of spray-dried milk were prepared using a miniature-scale Buchi Mini Spray Dryer B-290 (diameter 0.5 m, height 1.1 m). For each run, all inlet conditions were held constant except for feed type, inlet solids concentration, and inlet temperature. Skim milk at a solids concentration of 8.8% and whole milk at a solids concentration of 11% were dried at two inlet temperatures, 120 and 200°C. Lactose-free skim milk (8.8% solids concentration) and skim milk at a solids concentration of 41.2% were also dried at an inlet temperature of 200°C to assess the effects of milk feed type and inlet concentration, respectively. Equilibrium between the outlet product moisture content and the outlet gas conditions in the miniature spray dryer was not reached, unlike previous results for pilot-scale and larger dryers, so it appears that, in small (miniature-scale) dryers, the outlet moisture content is limited by kinetics and not by equilibrium. Calculated yields ranged from 10.4 to 82.7%, with whole milk giving significantly lower yields than skim milk, due to the sticky nature of fat found in whole milk. Lactose-free skim milk produced lower yields than skim milk dried at the same conditions, indicating that the lower glass-transition temperatures of the converted lactose sugars make these powders stickier. This sugar effect was not as large as that of the fat content. Comparisons between the SEM images, fractal dimensions, particle size distributions, and bulk densities showed that lower inlet temperatures produced particles of a more collapsed nature with a higher bulk density and lower fractal dimension than milk particles dried at higher temperatures. Also, feed solids concentration heavily influenced the shape of the particles, with high concentrations producing more spherical, less broken or shriveled particles with higher fractal dimensions, as the shell walls are thicker under these conditions. The fractal dimensions appeared to give generally consistent results for quantifying the average particle shapes.     

An Investigation and Quantitative Assessment of Particle Shape in Milk Powders from a Laboratory-Scale Spray Dryer

Seven samples of spray-dried milk were prepared using a miniature-scale Buchi Mini Spray Dryer B-290 (diameter 0.5 m, height 1.1 m). For each run, all inlet conditions were held constant except for feed type, inlet solids concentration, and inlet temperature. Skim milk at a solids concentration of 8.8% and whole milk at a solids concentration of 11% were dried at two inlet temperatures, 120 and 200°C. Lactose-free skim milk (8.8% solids concentration) and skim milk at a solids concentration of 41.2% were also dried at an inlet temperature of 200°C to assess the effects of milk feed type and inlet concentration, respectively. Equilibrium between the outlet product moisture content and the outlet gas conditions in the miniature spray dryer was not reached, unlike previous results for pilot-scale and larger dryers, so it appears that, in small (miniature-scale) dryers, the outlet moisture content is limited by kinetics and not by equilibrium. Calculated yields ranged from 10.4 to 82.7%, with whole milk giving significantly lower yields than skim milk, due to the sticky nature of fat found in whole milk. Lactose-free skim milk produced lower yields than skim milk dried at the same conditions, indicating that the lower glass-transition temperatures of the converted lactose sugars make these powders stickier. This sugar effect was not as large as that of the fat content. Comparisons between the SEM images, fractal dimensions, particle size distributions, and bulk densities showed that lower inlet temperatures produced particles of a more collapsed nature with a higher bulk density and lower fractal dimension than milk particles dried at higher temperatures. Also, feed solids concentration heavily influenced the shape of the particles, with high concentrations producing more spherical, less broken or shriveled particles with higher fractal dimensions, as the shell walls are thicker under these conditions. The fractal dimensions appeared to give generally consistent results for quantifying the average particle shapes.