Fresh blood of Tibetan sheep was subjected to protein separation and spray drying, and the effects of drying process on water content, yield and nitrogen soluble index of plasma powder from blood of Tibetan sheep were...Fresh blood of Tibetan sheep was subjected to protein separation and spray drying, and the effects of drying process on water content, yield and nitrogen soluble index of plasma powder from blood of Tibetan sheep were investigated. The results showed that the optimum separation parameters were a centrifugal speed at 6 000 r/min, centrifugal time of 20 min, a mass fraction of dry matter of 20%, an inlet air temperature at 180 ℃ and a feed rate at 400 ml/h, under which the plasma protein was a pale yellow powdery solid, indicating a good separation effect.展开更多
The microstructure and properties of TZP ceramics fabricated from spray dried powder differing in granule morphology and deformability are determined.The effects of the feed slurry solids con...The microstructure and properties of TZP ceramics fabricated from spray dried powder differing in granule morphology and deformability are determined.The effects of the feed slurry solids content on the granule character are discussed.The lower solid content results in hard and tough ‘donut’ shaped granules that resist deformation during compaction.The microphotograph shows that relatively large intergranular pores formed by incomplete deformation of granules persist during sintering and are the major strength limiting defects in fired material.Sintered material produced from uniform and deformable granules has a homogeneous microstructure and relatively high mean strength.展开更多
[Objective] Effects of different contents of calcium oxide on physicochemi- cal properties of spray-dried bayberry powder were studied. [Method] Bayberry pow- der produced from bayberry juice adding 0, 2 and 4 g/L cal...[Objective] Effects of different contents of calcium oxide on physicochemi- cal properties of spray-dried bayberry powder were studied. [Method] Bayberry pow- der produced from bayberry juice adding 0, 2 and 4 g/L calcium oxide using the spray drying technique has been selected. The physicochemical properties of the spray-dried bayberry powder were investigated by determining moisture content, colour, apparent density, wettability, angle of repose and moisture absorption rate of bayberry powder. [Result] The results showed that the content of calcium oxide had a significant effect on the moisture content and colour of bayberry powder. Effects of different contents of calcium oxide on the apparent density of spray-dried bayber- ry powder were not obvious. Adding calcium oxide had a significant effect on the wettability, angle of repose and moisture absorption rate of spray-dried bayberry powder, nevertheless, there was not obvious difference on these properties between adding 2 and 4 g/L calcium oxide. [Conclusion] The results confirmed that the con- tent of calcium oxide had a significant effect on the properties of spray-dried bay- berry powder.展开更多
Silicon/flake graphite/carbon (Si/FG/C) composites were synthesized with different dispersants via spray drying and subsequent pyrolysis, and effects of dispersants on the characteristics of the composites were inve...Silicon/flake graphite/carbon (Si/FG/C) composites were synthesized with different dispersants via spray drying and subsequent pyrolysis, and effects of dispersants on the characteristics of the composites were investigated. The structure and properties of the composites were determined by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and electrochemical measurements. The results show that samples have silicon/flake graphite/amorphous carbon composite structure, good spherical appearances, and better electrochemical performance than pure nano-Si and FG/C composites. Compared with the Si/FG/C composite using washing powder as dispersant, the Si/FG/C composite using sodium dodecyl benzene sulfonate (SDBS) as dispersant has better electrochemical performance with a reversible capacity of 602.68 mA·h/g, and a capacity retention ratio of 91.58 % after 20 cycles.展开更多
In order to enhance electrochemical properties of LiFePO4 (LFP) cathode materials, spherical porous nano/micro structured LFP/C cathode materials were synthesized by spray drying, followed by calcination. The result...In order to enhance electrochemical properties of LiFePO4 (LFP) cathode materials, spherical porous nano/micro structured LFP/C cathode materials were synthesized by spray drying, followed by calcination. The results show that the spherical precursors with the sizes of 0.5-5 μm can be completely converted to LFP/C when the calcination temperature is higher than 500 ℃. The LFP/C microspheres obtained at calcination temperature of 700 ℃ are composed of numerous particles with sizes of -20 nm, and have well-developed interconnected pore structure and large specific surface area of 28.77 mE/g. The specific discharge capacities of the LFP/C obtained at 700 ℃ are 162.43, 154.35 and 144.03 mA.h/g at 0.5C, 1C and 2C, respectively. Meanwhile, the capacity retentions can reach up to 100% after 50 cycles. The improved electrochemical properties of the materials are ascribed to a small Li+ diffusion resistance and special structure of LFP/C microspheres.展开更多
Jerusalem artichoke is an economic crop widely planted in saline-alkaline soil. The use of Jerusalem artichoke is of great significance. In this study, the response surface method was employed to optimize the effects ...Jerusalem artichoke is an economic crop widely planted in saline-alkaline soil. The use of Jerusalem artichoke is of great significance. In this study, the response surface method was employed to optimize the effects of processing variables (extraction temperature, pH, extraction time, and liquid-to- solid ratio) on the yield of Jerusalem artichoke pectin. Under the optimal extraction conditions: pHl .52, 63.62 min, 100℃ and a liquid-to-solid ratio of 44.4 mL/g, the maximum pectin yield was predicted to be 18.76%. Experiments were conducted under these optimal conditions and a pectin yield of 18.52+0.90% was obtained, which validated the model prediction. The effects of different drying methods (freeze drying, spray drying and vacuum drying) on the properties of Jerusalem artichoke pectin were evaluated and they were compared with apple pectin. FTIR spectral analysis showed no major structural differences in Jerusalem artichoke pectin samples produced by various drying treatments. The antioxidant activities of pectin dried by different methods were investigated using in vitro hydroxyl and DPPH radical scavenging systems. The results revealed that the activities of spray dried pectin (SDP) and apple pectin (AP) were stronger than those of vacuum oven dried pectin (ODP) and vacuum freeze dried pectin (FDP). Therefore compared with the other two drying methods, the spray drying method was the best.展开更多
With concentrated juice of mulberry as raw material, the influence of type and dosage of dry aid, the inlet air tempera- ture, inlet flow rate, and rotating speed on spray drying was studied. The spray drying processi...With concentrated juice of mulberry as raw material, the influence of type and dosage of dry aid, the inlet air tempera- ture, inlet flow rate, and rotating speed on spray drying was studied. The spray drying processing conditions of mulberry pow- der were optimized by the L9 (3^4) orthogonal test on the basis of single factor experiment. The results showed that optimum technical parameters to produce mulberry powder were: lS-cyclodextrin as dry aids with dosage of 30%, inlet air temperature of 180 ℃, rotating speed of 18 000 r/min and inlet flow rate of 30 mL/min. The mulberry powder under this optimum process conditions had a loose structure and bright color, fruity flavor was rich, the anthocyanin content for 54.67 mg/g, moisture content for 5.6% and sensory scores for 83.展开更多
Wall deposition occurs in spray dryers when dried or partially dried particles contact and adhere to the walls during operation, thus reducing the yield of product collected. Wall deposits also present a product conta...Wall deposition occurs in spray dryers when dried or partially dried particles contact and adhere to the walls during operation, thus reducing the yield of product collected. Wall deposits also present a product contamination risk and a fire or explosion risk when spray drying products that oxidize exothermically, such as milk powder. Re-entrainment is the resuspension of spray dryer wall deposits into the main gas stream for collection as product. Literature suggests that the process for re-entrainment of particles from spray dryer wall deposits is strongly dependent on particle size and gas velocity.展开更多
Water-droplet size and velocity measurements were taken throughout two different sprays produced by a single nozzle and two nozzles pointed towards each other. The aim of this investigation was to understand the manne...Water-droplet size and velocity measurements were taken throughout two different sprays produced by a single nozzle and two nozzles pointed towards each other. The aim of this investigation was to understand the manner in which the motion of the droplets in a spray leads to agglomeration of these droplets. It appears that the inertia of the droplets plays an important role in the redistribution of droplets throughout a spray. Larger droplets tend to concentrate at the outer portions of the spray, because they are able to maintain their radial momentum farther downstream of a nozzle, while the smaller droplets follow the airflow more closely and thus collect in the core of the spray. Agglomeration can result from both turbulent collisions and collisions due to the relative velocities of the droplets. The difference between the agglomeration rates in the sprays from a single nozzle and two-nozzles pointed towards each other was difficult to resolve in these experiments, although the results suggest that the outer portions of both sprays should be investigated more closely for evidence of agglomeration.展开更多
Spray drying is an important continuous industrial process for drying pumpable liquid formulations irrespective of their heat sensitivity, rheology, solids content and processing rate. Furthermore spray drying has the...Spray drying is an important continuous industrial process for drying pumpable liquid formulations irrespective of their heat sensitivity, rheology, solids content and processing rate. Furthermore spray drying has the capability through drying chamber design, plant layout and mode of operation to produce dried products of specific particulate size and morphology. These are important aspects when spray drying technology is applied to the needs of customized powder manufacture. There are many examples in industry where spray dried powders have to meet stringent specifications set by such factors as end-product powder quality standards dictated by global competition,dry raw material characteristics required for optimum downstream processing, and dry materials handling to comply with environmental, health and safety issues. Spray drying is no longer regarded just as a convective industrial drying concept, but also as an integral part of modern manufacturing practices applying powder technology. This paper reviews the aspects of spray dryer design and operation for consideration when customized powder manufacture is involved.展开更多
The paper is focused on identifying error sources in computational fluid dynamics(CFD) predictions of a spray drying process. Seven groups of drying and atomisation parameters were selected for analysis and 13simulati...The paper is focused on identifying error sources in computational fluid dynamics(CFD) predictions of a spray drying process. Seven groups of drying and atomisation parameters were selected for analysis and 13simulation trials were performed. The theoretical results were compared with experimental data and sensitivity of the simulation results to the analysed factors was determined. The following parameters affecting the accuracy of CFD spray modelling were found: gas turbulence model, particle dispersion, atomising air, initial parameters of atomisation and heat losses to the environment. A major difference in the errors committed during modelling of spray drying process for fine and coarse sprays was observed.展开更多
[Objective] The aim was to study the microcapsulation of onion oil with double place separation-coacevation and spray drying. [Method] The effect of processing parameters which included the different wall material com...[Objective] The aim was to study the microcapsulation of onion oil with double place separation-coacevation and spray drying. [Method] The effect of processing parameters which included the different wall material combination,the ratio between the wall material,the core material content and the feed concentration on the efficiency and yield of microencapsulated was evaluated by single factor experiments. [Result] Through orthogonal optimization experiments, the optimum condition was as follows: the ratio of Arabic gum and maltodextrin ration was 1∶1, the core content was 25%, feed composition was 18%, and the microencapsulation efficiency and yield can reach 80.7% and 95.3% respectively. [Conclusion] The microcapsulaiton of onion oil with complex coacervation spray drying method can increase membrane thickness, improve core stability and prolong shelf life of products.展开更多
Almost without exception literature data and modeling effort are understandably devoted to water as the sprayed liquid since it constitutes the most common liquid used in spray drying applications. In selected applica...Almost without exception literature data and modeling effort are understandably devoted to water as the sprayed liquid since it constitutes the most common liquid used in spray drying applications. In selected applications, however, the liquid making up the solution or suspension may not be water. The objective of this work is to examine the differences in flow patterns, thermal behavior and drying rates caused by different liquids having different thermo-physical properties spray into a spray dryer using a computational fluid dynamic model.Numerical experiments were carried out for water (base case), ethyl alcohol and isopropyl alcohol-the latter two as model non-aqueous liquids. The chamber geometry was cylinder type with a co-current axial pressure nozzle and also an axial central exit so that the configuration is two dimensional and axi-symmetric. It is shown that the liquid properties can have major influence on the thermal field, droplet trajectories, residence times and overall evaporation capacity when all parameters of the problem are held fixed. Deviations from the single phase turbulent airflow in the same chamber without spray are different for the three liquids examined.展开更多
AIM:To investigate the cytotoxic effects of spray-dried extracts of Phyllanthus niruri in combination with cis- platin on two cancer cell lines. METHODS: Colorectal carcinoma (HT29) and human hepatocellular carcin...AIM:To investigate the cytotoxic effects of spray-dried extracts of Phyllanthus niruri in combination with cis- platin on two cancer cell lines. METHODS: Colorectal carcinoma (HT29) and human hepatocellular carcinoma (HepG2) cells were treated with spray-dried extracts of Phyllanthus niruri (SDEPN) either alone or in combination with cisplatin at differ- ent concentrations (0.5 mg/mL and 1 mg/mL) for 4 h and 24 h. To verify and quantify cancer cells treated with these products as well as identify the cell cycle stage and cell viability, we stained the cells with prop- idium iodide and assessed them by flow cytometry. The percentage of cells in different cell cycle phases was quantified and data were expressed as histo- grams. Significant differences between groups were determined using analysis of variance and Bonferroni's test, as indicated. A value of P 〈 0.05 was considered to be statistically significant. RESULTS: SDEPN had significantly different cyto- toxic effects on HT29 (2.81 4- 0.11 vs 3.51 4- 1.13, P 〉 0.05) and HepG2 (5.07± 0.3 vs 15.9 ± 1.04, P 〈 0.001) cells when compared to control cells for 4 h. SDEPN also had significantly different cytotoxic effects on HT29 (1.91 ± 0.57 vs 4.53± 1.22, P 〉 0.05) and HepG2 (14.56 ± 1.6 vs 35.67 ± 3.94, P 〈 0.001) cells when compared to control cells for 24 h. Both cell lines were killed by cisplatin in a dose-dependent manner compared to control cells (HepG2 cells for 4 h: 10.78 ± 1.58 vs 53.89 ± 1.53, P 〈 0.001; 24 h: 8.9 ± 1.43 vs 62.78 ± 1.87, P 〈 0.001 and HT29 cells for 4 h: 9.52 ±0.913 vs 49.86 ± 2.89, P 〈 0.001; 24 h: 11.78 ± 1.05 vs 53.34 ± 2.65, P 〈 0.001). In HT29 cells, pretreat- ment with SDEPN and subsequent treatment with cis-platin resulted in a greater number of cells being killed (12.78 ± 1.01 vs 93.76 ± 1.6, P 〈 0.001). HepG2 cells showed significant cell killing with treatment with SDEPN when combined with cisplatin (12.87 ± 2.78 vs 78.8 ± 3.02, P 〈 0.001). CONCLUSION: SDEPN is selectively toxic against two cancer cell lines. Moreover, SDEPN in combination with cisplatin induces a synergistic increase in the cell death of both HT29 and HepG2 cells.展开更多
A facile and user friendly technique to immobilize the late-transition metal complexes on spherical MgCl2/SiO2/THF support has been developed. The spherical MgCl2/SiO2/THF-supported late-transition metal catalysts 2,6...A facile and user friendly technique to immobilize the late-transition metal complexes on spherical MgCl2/SiO2/THF support has been developed. The spherical MgCl2/SiO2/THF-supported late-transition metal catalysts 2,6-bis-[1-(2,6-dimethylphenylimino)ethyl]pyridine iron(II) dichloride(SC-A) and 1,4-bis(2,6-dimethylphenyl)- acenaphthene diimine nickel(II) dibromide(SC-B) for ethylene polymerization has been prepared by spray-drying technique using tetrahydrofuran suspension containing MgCl2, SiO2 and late-transition metal complexes. The catalysts were characterized by BET, XRD, SEM and the polymers were analyzed using GPC, DSC and 13C-NMR. The test results show that spray-drying is a very effective method for immobilizing late-transition metal catalysts for ethylene polymerization. Among six kinds of cocatalysts for olefin polymerization, TMA and TEA were confirmed to be more effective than other compounds for the ethylene polymerization system using the catalyst SC-A. For the case of the catalyst SC-B, DEAC showed the best performance as cocatalysts in ethylene polymerization. The replication of the catalyst morphology was found in the resultant polyethylene.展开更多
An industrialized technique of preparation for oxidized com starch using oxygen as oxidant was investigated in this paper. The industrialized preparation parameters were optimized as follows: reaction temperature 85-...An industrialized technique of preparation for oxidized com starch using oxygen as oxidant was investigated in this paper. The industrialized preparation parameters were optimized as follows: reaction temperature 85-95 ℃, oxygen flow rate 8-12 L/min, reaction time 210 min, the ratio of starch to water 1:5, 3.5 wt% of NaOH and 0.1 wt% of catalyst. The experimental results show that the concentration of hydrolysate-oxidaton product is 16-18 wt%. The powdered products were gained through dehydrated and powdered process using quadruple-effect evaporator, spray drying tower and guide shell mixer. The composting test indicates that the degradability of the oxidized corn starch can reach 76.4%. The complexation capacity of calcium ions reaches 108.5 mg per gram oxidized starch, and the detergency ratio (P) reaches 1.30 as builder.展开更多
A detached eddy simulation(DES) and a k-ε-based Reynolds-averaged Navier–Stokes(RANS) calculation on the co-current spray drying chamber is presented. The DES used here is based on the Spalart–Allmaras(SA) turbulen...A detached eddy simulation(DES) and a k-ε-based Reynolds-averaged Navier–Stokes(RANS) calculation on the co-current spray drying chamber is presented. The DES used here is based on the Spalart–Allmaras(SA) turbulence model, whereas the standard k-ε(SKE) was considered here for comparison purposes. Predictions of the mean axial velocity, temperature and humidity profile have been evaluated and compared with experimental measurements. The effects of the turbulence model on the predictions of the mean axial velocity, temperature and the humidity profile are most noticeable in the(highly anisotropic) spraying region. The findings suggest that DES provide a more accurate prediction(with error less than 5%) of the flow field in a spray drying chamber compared with RANS-based k-ε models. The DES simulation also confirmed the presence of anisotropic turbulent flow in the spray dryer from the analysis of the velocity component fluctuations and turbulent structure as illustrated by the Q-criterion.展开更多
This article presents a mathematical model of heat and mass transfer for the process of fluidized-bed spray granulation, which can be applied in the analysis of bed temperature profile, temperature and humidity of out...This article presents a mathematical model of heat and mass transfer for the process of fluidized-bed spray granulation, which can be applied in the analysis of bed temperature profile, temperature and humidity of outlet gas and moisture content of particles. Effects of operation parameters on the batch granulation are investigated. The theoretical calculation agrees reasonably well with the experimental data.展开更多
基金Supported by"123"Science and Technology Support Program from Science and Technology Department of Qinghai Province(2014-GX-136A)~~
文摘Fresh blood of Tibetan sheep was subjected to protein separation and spray drying, and the effects of drying process on water content, yield and nitrogen soluble index of plasma powder from blood of Tibetan sheep were investigated. The results showed that the optimum separation parameters were a centrifugal speed at 6 000 r/min, centrifugal time of 20 min, a mass fraction of dry matter of 20%, an inlet air temperature at 180 ℃ and a feed rate at 400 ml/h, under which the plasma protein was a pale yellow powdery solid, indicating a good separation effect.
文摘The microstructure and properties of TZP ceramics fabricated from spray dried powder differing in granule morphology and deformability are determined.The effects of the feed slurry solids content on the granule character are discussed.The lower solid content results in hard and tough ‘donut’ shaped granules that resist deformation during compaction.The microphotograph shows that relatively large intergranular pores formed by incomplete deformation of granules persist during sintering and are the major strength limiting defects in fired material.Sintered material produced from uniform and deformable granules has a homogeneous microstructure and relatively high mean strength.
基金Supported by the Project of Natural Science Fund of Zhejiang Province(Y3110376)~~
文摘[Objective] Effects of different contents of calcium oxide on physicochemi- cal properties of spray-dried bayberry powder were studied. [Method] Bayberry pow- der produced from bayberry juice adding 0, 2 and 4 g/L calcium oxide using the spray drying technique has been selected. The physicochemical properties of the spray-dried bayberry powder were investigated by determining moisture content, colour, apparent density, wettability, angle of repose and moisture absorption rate of bayberry powder. [Result] The results showed that the content of calcium oxide had a significant effect on the moisture content and colour of bayberry powder. Effects of different contents of calcium oxide on the apparent density of spray-dried bayber- ry powder were not obvious. Adding calcium oxide had a significant effect on the wettability, angle of repose and moisture absorption rate of spray-dried bayberry powder, nevertheless, there was not obvious difference on these properties between adding 2 and 4 g/L calcium oxide. [Conclusion] The results confirmed that the con- tent of calcium oxide had a significant effect on the properties of spray-dried bay- berry powder.
基金Project(2011FJ1005)supported by the Science and Technology Programs of Hunan Province,China
文摘Silicon/flake graphite/carbon (Si/FG/C) composites were synthesized with different dispersants via spray drying and subsequent pyrolysis, and effects of dispersants on the characteristics of the composites were investigated. The structure and properties of the composites were determined by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and electrochemical measurements. The results show that samples have silicon/flake graphite/amorphous carbon composite structure, good spherical appearances, and better electrochemical performance than pure nano-Si and FG/C composites. Compared with the Si/FG/C composite using washing powder as dispersant, the Si/FG/C composite using sodium dodecyl benzene sulfonate (SDBS) as dispersant has better electrochemical performance with a reversible capacity of 602.68 mA·h/g, and a capacity retention ratio of 91.58 % after 20 cycles.
基金Project(2013AA050901)supported by the National High-tech Research and Development Program of China
文摘In order to enhance electrochemical properties of LiFePO4 (LFP) cathode materials, spherical porous nano/micro structured LFP/C cathode materials were synthesized by spray drying, followed by calcination. The results show that the spherical precursors with the sizes of 0.5-5 μm can be completely converted to LFP/C when the calcination temperature is higher than 500 ℃. The LFP/C microspheres obtained at calcination temperature of 700 ℃ are composed of numerous particles with sizes of -20 nm, and have well-developed interconnected pore structure and large specific surface area of 28.77 mE/g. The specific discharge capacities of the LFP/C obtained at 700 ℃ are 162.43, 154.35 and 144.03 mA.h/g at 0.5C, 1C and 2C, respectively. Meanwhile, the capacity retentions can reach up to 100% after 50 cycles. The improved electrochemical properties of the materials are ascribed to a small Li+ diffusion resistance and special structure of LFP/C microspheres.
基金Supported by the National High Technology Research and Development Program of China(863 Program)(No.2012AA021205)the National Key Technology R&D Program of China(No.2011BAC02B04)
文摘Jerusalem artichoke is an economic crop widely planted in saline-alkaline soil. The use of Jerusalem artichoke is of great significance. In this study, the response surface method was employed to optimize the effects of processing variables (extraction temperature, pH, extraction time, and liquid-to- solid ratio) on the yield of Jerusalem artichoke pectin. Under the optimal extraction conditions: pHl .52, 63.62 min, 100℃ and a liquid-to-solid ratio of 44.4 mL/g, the maximum pectin yield was predicted to be 18.76%. Experiments were conducted under these optimal conditions and a pectin yield of 18.52+0.90% was obtained, which validated the model prediction. The effects of different drying methods (freeze drying, spray drying and vacuum drying) on the properties of Jerusalem artichoke pectin were evaluated and they were compared with apple pectin. FTIR spectral analysis showed no major structural differences in Jerusalem artichoke pectin samples produced by various drying treatments. The antioxidant activities of pectin dried by different methods were investigated using in vitro hydroxyl and DPPH radical scavenging systems. The results revealed that the activities of spray dried pectin (SDP) and apple pectin (AP) were stronger than those of vacuum oven dried pectin (ODP) and vacuum freeze dried pectin (FDP). Therefore compared with the other two drying methods, the spray drying method was the best.
文摘With concentrated juice of mulberry as raw material, the influence of type and dosage of dry aid, the inlet air tempera- ture, inlet flow rate, and rotating speed on spray drying was studied. The spray drying processing conditions of mulberry pow- der were optimized by the L9 (3^4) orthogonal test on the basis of single factor experiment. The results showed that optimum technical parameters to produce mulberry powder were: lS-cyclodextrin as dry aids with dosage of 30%, inlet air temperature of 180 ℃, rotating speed of 18 000 r/min and inlet flow rate of 30 mL/min. The mulberry powder under this optimum process conditions had a loose structure and bright color, fruity flavor was rich, the anthocyanin content for 54.67 mg/g, moisture content for 5.6% and sensory scores for 83.
文摘Wall deposition occurs in spray dryers when dried or partially dried particles contact and adhere to the walls during operation, thus reducing the yield of product collected. Wall deposits also present a product contamination risk and a fire or explosion risk when spray drying products that oxidize exothermically, such as milk powder. Re-entrainment is the resuspension of spray dryer wall deposits into the main gas stream for collection as product. Literature suggests that the process for re-entrainment of particles from spray dryer wall deposits is strongly dependent on particle size and gas velocity.
文摘Water-droplet size and velocity measurements were taken throughout two different sprays produced by a single nozzle and two nozzles pointed towards each other. The aim of this investigation was to understand the manner in which the motion of the droplets in a spray leads to agglomeration of these droplets. It appears that the inertia of the droplets plays an important role in the redistribution of droplets throughout a spray. Larger droplets tend to concentrate at the outer portions of the spray, because they are able to maintain their radial momentum farther downstream of a nozzle, while the smaller droplets follow the airflow more closely and thus collect in the core of the spray. Agglomeration can result from both turbulent collisions and collisions due to the relative velocities of the droplets. The difference between the agglomeration rates in the sprays from a single nozzle and two-nozzles pointed towards each other was difficult to resolve in these experiments, although the results suggest that the outer portions of both sprays should be investigated more closely for evidence of agglomeration.
文摘Spray drying is an important continuous industrial process for drying pumpable liquid formulations irrespective of their heat sensitivity, rheology, solids content and processing rate. Furthermore spray drying has the capability through drying chamber design, plant layout and mode of operation to produce dried products of specific particulate size and morphology. These are important aspects when spray drying technology is applied to the needs of customized powder manufacture. There are many examples in industry where spray dried powders have to meet stringent specifications set by such factors as end-product powder quality standards dictated by global competition,dry raw material characteristics required for optimum downstream processing, and dry materials handling to comply with environmental, health and safety issues. Spray drying is no longer regarded just as a convective industrial drying concept, but also as an integral part of modern manufacturing practices applying powder technology. This paper reviews the aspects of spray dryer design and operation for consideration when customized powder manufacture is involved.
文摘The paper is focused on identifying error sources in computational fluid dynamics(CFD) predictions of a spray drying process. Seven groups of drying and atomisation parameters were selected for analysis and 13simulation trials were performed. The theoretical results were compared with experimental data and sensitivity of the simulation results to the analysed factors was determined. The following parameters affecting the accuracy of CFD spray modelling were found: gas turbulence model, particle dispersion, atomising air, initial parameters of atomisation and heat losses to the environment. A major difference in the errors committed during modelling of spray drying process for fine and coarse sprays was observed.
基金Supported by the Scientific Research Program for PostgraduateStudent in Weinan Normal Unviersity( 12YKZ040)
文摘[Objective] The aim was to study the microcapsulation of onion oil with double place separation-coacevation and spray drying. [Method] The effect of processing parameters which included the different wall material combination,the ratio between the wall material,the core material content and the feed concentration on the efficiency and yield of microencapsulated was evaluated by single factor experiments. [Result] Through orthogonal optimization experiments, the optimum condition was as follows: the ratio of Arabic gum and maltodextrin ration was 1∶1, the core content was 25%, feed composition was 18%, and the microencapsulation efficiency and yield can reach 80.7% and 95.3% respectively. [Conclusion] The microcapsulaiton of onion oil with complex coacervation spray drying method can increase membrane thickness, improve core stability and prolong shelf life of products.
文摘Almost without exception literature data and modeling effort are understandably devoted to water as the sprayed liquid since it constitutes the most common liquid used in spray drying applications. In selected applications, however, the liquid making up the solution or suspension may not be water. The objective of this work is to examine the differences in flow patterns, thermal behavior and drying rates caused by different liquids having different thermo-physical properties spray into a spray dryer using a computational fluid dynamic model.Numerical experiments were carried out for water (base case), ethyl alcohol and isopropyl alcohol-the latter two as model non-aqueous liquids. The chamber geometry was cylinder type with a co-current axial pressure nozzle and also an axial central exit so that the configuration is two dimensional and axi-symmetric. It is shown that the liquid properties can have major influence on the thermal field, droplet trajectories, residence times and overall evaporation capacity when all parameters of the problem are held fixed. Deviations from the single phase turbulent airflow in the same chamber without spray are different for the three liquids examined.
基金Supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq (470179/2009-0) for financial support and Postgraduate Program in Pharmaceutical Sciences,Federal University of Rio Grande do Norte
文摘AIM:To investigate the cytotoxic effects of spray-dried extracts of Phyllanthus niruri in combination with cis- platin on two cancer cell lines. METHODS: Colorectal carcinoma (HT29) and human hepatocellular carcinoma (HepG2) cells were treated with spray-dried extracts of Phyllanthus niruri (SDEPN) either alone or in combination with cisplatin at differ- ent concentrations (0.5 mg/mL and 1 mg/mL) for 4 h and 24 h. To verify and quantify cancer cells treated with these products as well as identify the cell cycle stage and cell viability, we stained the cells with prop- idium iodide and assessed them by flow cytometry. The percentage of cells in different cell cycle phases was quantified and data were expressed as histo- grams. Significant differences between groups were determined using analysis of variance and Bonferroni's test, as indicated. A value of P 〈 0.05 was considered to be statistically significant. RESULTS: SDEPN had significantly different cyto- toxic effects on HT29 (2.81 4- 0.11 vs 3.51 4- 1.13, P 〉 0.05) and HepG2 (5.07± 0.3 vs 15.9 ± 1.04, P 〈 0.001) cells when compared to control cells for 4 h. SDEPN also had significantly different cytotoxic effects on HT29 (1.91 ± 0.57 vs 4.53± 1.22, P 〉 0.05) and HepG2 (14.56 ± 1.6 vs 35.67 ± 3.94, P 〈 0.001) cells when compared to control cells for 24 h. Both cell lines were killed by cisplatin in a dose-dependent manner compared to control cells (HepG2 cells for 4 h: 10.78 ± 1.58 vs 53.89 ± 1.53, P 〈 0.001; 24 h: 8.9 ± 1.43 vs 62.78 ± 1.87, P 〈 0.001 and HT29 cells for 4 h: 9.52 ±0.913 vs 49.86 ± 2.89, P 〈 0.001; 24 h: 11.78 ± 1.05 vs 53.34 ± 2.65, P 〈 0.001). In HT29 cells, pretreat- ment with SDEPN and subsequent treatment with cis-platin resulted in a greater number of cells being killed (12.78 ± 1.01 vs 93.76 ± 1.6, P 〈 0.001). HepG2 cells showed significant cell killing with treatment with SDEPN when combined with cisplatin (12.87 ± 2.78 vs 78.8 ± 3.02, P 〈 0.001). CONCLUSION: SDEPN is selectively toxic against two cancer cell lines. Moreover, SDEPN in combination with cisplatin induces a synergistic increase in the cell death of both HT29 and HepG2 cells.
基金supported by the National Natural Science Foundation of China (Grant No.U1162114)the Science Foundation of Tianjin University of Science & Technology (20090420)
文摘A facile and user friendly technique to immobilize the late-transition metal complexes on spherical MgCl2/SiO2/THF support has been developed. The spherical MgCl2/SiO2/THF-supported late-transition metal catalysts 2,6-bis-[1-(2,6-dimethylphenylimino)ethyl]pyridine iron(II) dichloride(SC-A) and 1,4-bis(2,6-dimethylphenyl)- acenaphthene diimine nickel(II) dibromide(SC-B) for ethylene polymerization has been prepared by spray-drying technique using tetrahydrofuran suspension containing MgCl2, SiO2 and late-transition metal complexes. The catalysts were characterized by BET, XRD, SEM and the polymers were analyzed using GPC, DSC and 13C-NMR. The test results show that spray-drying is a very effective method for immobilizing late-transition metal catalysts for ethylene polymerization. Among six kinds of cocatalysts for olefin polymerization, TMA and TEA were confirmed to be more effective than other compounds for the ethylene polymerization system using the catalyst SC-A. For the case of the catalyst SC-B, DEAC showed the best performance as cocatalysts in ethylene polymerization. The replication of the catalyst morphology was found in the resultant polyethylene.
文摘An industrialized technique of preparation for oxidized com starch using oxygen as oxidant was investigated in this paper. The industrialized preparation parameters were optimized as follows: reaction temperature 85-95 ℃, oxygen flow rate 8-12 L/min, reaction time 210 min, the ratio of starch to water 1:5, 3.5 wt% of NaOH and 0.1 wt% of catalyst. The experimental results show that the concentration of hydrolysate-oxidaton product is 16-18 wt%. The powdered products were gained through dehydrated and powdered process using quadruple-effect evaporator, spray drying tower and guide shell mixer. The composting test indicates that the degradability of the oxidized corn starch can reach 76.4%. The complexation capacity of calcium ions reaches 108.5 mg per gram oxidized starch, and the detergency ratio (P) reaches 1.30 as builder.
基金Supported by the Ministry of Education Malaysia through RACE(RDU121308)and FRGS(RDU130136)
文摘A detached eddy simulation(DES) and a k-ε-based Reynolds-averaged Navier–Stokes(RANS) calculation on the co-current spray drying chamber is presented. The DES used here is based on the Spalart–Allmaras(SA) turbulence model, whereas the standard k-ε(SKE) was considered here for comparison purposes. Predictions of the mean axial velocity, temperature and humidity profile have been evaluated and compared with experimental measurements. The effects of the turbulence model on the predictions of the mean axial velocity, temperature and the humidity profile are most noticeable in the(highly anisotropic) spraying region. The findings suggest that DES provide a more accurate prediction(with error less than 5%) of the flow field in a spray drying chamber compared with RANS-based k-ε models. The DES simulation also confirmed the presence of anisotropic turbulent flow in the spray dryer from the analysis of the velocity component fluctuations and turbulent structure as illustrated by the Q-criterion.
文摘This article presents a mathematical model of heat and mass transfer for the process of fluidized-bed spray granulation, which can be applied in the analysis of bed temperature profile, temperature and humidity of outlet gas and moisture content of particles. Effects of operation parameters on the batch granulation are investigated. The theoretical calculation agrees reasonably well with the experimental data.