Prediction of Final Product Properties After Cocurrent Spray Drying

Abstract

The effect of drying and atomization conditions on the physical properties of powders for agglomerate-like materials and skin-forming material are studied in this article. A neural model is used for powder bulk and tapped density predictions.     

The Influence of the Spray Drying Process on Product Properties

Uniform and repeatable product characteristics are critical in the performance and acceptance of consumer products, and the spray drying process can have a major influence on achieving these characteristics. This article shares experiences in the Spray Drying of powdered detergent granules in Procter & Gamble. It looks at the influence of both process operation and process equipment design on product characteristics. Procter & Gamble (P&G) is a major global producer of consumer products in the areas of fabric and home care; personal and beauty care; health care; and snacks and beverages. Whilst different drying operations, and product quality measuring tools are mentioned by Genskow (Genskow, L.R.¹ Considerations in Drying Consumer Products, Proceedings of 6th International Drying Symposium, Versailles, September, 1988; Keynote lecture, 39-46.) as being involved in all of the categories of Company production, I will concentrate on the counter-current Spray Drying process and controls, used in the manufacture of most of the detergent granules business of P&G. This area is the oldest and largest of the Company's core business activities. Innovative technology development is critical in continuing to satisfy the consumer need for performance and value. Use of modeling in the spray drying process is helping the Company to move faster in delivering these advanced technologies. And, through better understanding of the process, it is possible to minimize capital expenditure, and improve trouble-shooting ability across the global production facilities.     

The Influence of the Spray Drying Process on Product Properties

Abstract

Uniform and repeatable product characteristics are critical in the performance and acceptance of consumer products, and the spray drying process can have a major influence on achieving these characteristics. This article shares experiences in the Spray Drying of powdered detergent granules in Procter & Gamble. It looks at the influence of both process operation and process equipment design on product characteristics. Procter & Gamble (P&G) is a major global producer of consumer products in the areas of fabric and home care; personal and beauty care; health care; and snacks and beverages. Whilst different drying operations, and product quality measuring tools are mentioned by Genskow (Genskow, L.R.¹ Considerations in Drying Consumer Products, Proceedings of 6th International Drying Symposium, Versailles, September, 1988; Keynote lecture, 39–46.) as being involved in all of the categories of Company production, I will concentrate on the counter-current Spray Drying process and controls, used in the manufacture of most of the detergent granules business of P&G. This area is the oldest and largest of the Company's core business activities. Innovative technology development is critical in continuing to satisfy the consumer need for performance and value. Use of modeling in the spray drying process is helping the Company to move faster in delivering these advanced technologies. And, through better understanding of the process, it is possible to minimize capital expenditure, and improve trouble-shooting ability across the global production facilities.     

Development of a Phytopharmaceutical Intermediate Product via Spray Drying

The influence of concentration and incorporation time of different drying excipients on the processing yields and physical properties of Eugenia dysenterica DC spray-dried extracts were investigated following a factorial design. Under the established conditions, the process yield ranged from 57.55 to 89.14%, and in most experiments, the recovered products presented suitable flowability and compressibility, as demonstrated by the Hausner factor, Carr index, and angle of repose. Additionally, in a general way, the parameters related to the dried products' flowability varied over a range acceptable for pharmaceutical purposes. An analysis of variance (ANOVA) proved that both factors and some of their interactions significantly affected most of the investigated responses at different levels. Mannitol proved to be an interesting alternative as an excipient for the drying of herbal extracts, even at low concentrations such as 12.5%. Furthermore, these results imply that the best condition to obtain dry extracts of E. dysenterica with high performance and adequate pharmacotechnical properties involves the lowest concentration and the highest incorporation time of mannitol.     

火焰喷雾干燥

阐述了一种新型的喷雾干燥方法,即伴随雾化介质被点燃的喷雾干燥,称为火焰喷雾干燥．并提供了初步研究结果。火焰喷雾干燥过程中溶剂蒸发所需能量来自于燃烧喷雾介质中的易燃组分。此种方法不但可以干燥舍有可燃溶剂的溶液、浆料、乳剂或糊剂,而且可以通过添加与干燥产品类型和用途相关的可燃物对非易燃物干燥。因动力源直接位于喷雾,蒸发区域中,不但可以较好地利用能源、减少载能体的消耗,而且可以减少有害气体的排放。火焰喷雾干燥过程的载能体包括多种类型可燃性液体组分,例如来自可再生能源的生物乙醇或植物油。可燃性喷雾组分浓度的选择是火焰喷雾干燥过程的基本。因此本文阐述了浓度对所得产品品质的影响。研究了两种不同热敏性的物料,即麦芽糖糊精溶液和陶瓷材料的悬浮液。研究表明,火焰喷雾干燥过程是目前干燥方法中一种有趣的替代方法,首先可用于干燥低热敏性材料,如陶瓷材料。     

喷雾反应干燥技术

介绍了喷雾反应干燥的原理和类型,可将反应沉淀、干燥和研磨汇集成一个操作,为解决某些工艺难题提供了新的方法。讨论了4个方面的数学模型。介绍了在超微粉体的制备和烟气脱硫方面的应用。     

Microparticulated Hydrochlorothiazide Solid Dispersion: Enhancing Dissolution Properties via Spray Drying

The aim of the present study was to obtain microparticles of hydrochlorothiazide, a diuretic drug that practically insoluble in water, by spray drying and to investigate the influence of process parameters using a three-level, three-factor Box-Behnken design. Process yields, moisture content, particle size, flowability, and solubility were used to evaluate the spray-dried microparticles. The data were analyzed by response surface methodology using analysis of variance. The independent variables studied were outlet temperature, atomization pressure, and drug content. The formulations were prepared using polyvinylpyrrolidone and colloidal silicon dioxide as the hydrophilic carrier and drying aid, respectively. The microparticle yield ranged from 18.15 to 59.02% and resulted in adequate flow (17 to 32°), moisture content between 2.52 to 6.18%, and mean particle size from 45 to 59 µm. The analysis of variance showed that the factors studied influenced the yields, moisture content, angle of repose, and solubility. Thermal analysis and X-ray diffractometry evidenced no drug interactions or chemical modifications. Photomicrographs obtained by scanning electron microscopy showed spherical particles. The solubility and dissolution rates of hydrochlorothiazide were remarkably improved when compared with pure drug. Therefore, the results confirmed the high potential of the spray-drying technique to obtain microparticulate hydrochlorothiazide with enhanced pharmaceutical and dissolution properties.     

Effect of Wall Surface Properties at Different Drying Kinetics on the Deposition Problem in Spray Drying

Current methods in alleviating the wall deposition problem in spray drying emphasize mainly controlling the stickiness of the drying particles and less attention is placed on the properties of the dryer wall. In this experimental study, the effect of wall surface properties on the deposition mechanism has been investigated. Properties considered in classifying different wall materials were surface energy, roughness, and dielectric properties. The model solution contained sucrose, representing low-molecular-weight sugars commonly encountered in spray drying of fruit and vegetable juices. The effect of wall properties on deposition was explored at different drying rates producing particles of different surface rigidity. Larger surface roughness produced higher deposition fluxes for particles with high impact velocity and moisture. Surface energy and surface roughness were found to have no significant effect for dry rigid particles at the middle and bottom elevation of the drying chamber. However, material with lower surface energy (Teflon) exhibited less deposition for rubbery particles at such elevations. Analysis shows that dielectric wall material (Teflon) tends to enhance deposition of dry particles because of attrition at the surface. Higher wall temperature was found to produce slightly more deposition. The results of this work give a general indication of the effect of wall material on the deposition problem and provide the fundamental understanding for further studies along this line. Proper selection of dryer wall material will provide potential alternatives for reducing the deposition problem.     

Spray Drying Tower Experiments

The article presents a full set of spray drying experiments for selected products performed in a co-current spray drying tower developed at Lodz Technical University. The experiments enabled identification of process and atomization parameters (feed properties, feed rate and feed temperature, drying agent temperature, air flow rate, atomization ratio, etc.) on drying and degradation kinetics, spray structure, particle residence time, and final product properties. Drying agent temperature measurements showed, in all cases, the initial increase of gas temperature in the spray envelope caused by the spray expansion and then a decrease induced by liquid evaporation and heat losses to the environment. PDA analysis confirmed that the initial velocity of particles was a function of a diameter and also the function of the distance from the axis. Practically an identical particle size distribution was observed in each cross-sectional area of the dryer. Negative values of particle velocity in the vicinity of the axis and at the edge of the spray envelope were found which proved that recirculation of particles appeared in the column. Analysis of final product properties showed that for agglomerate-like materials a decrease of bulk density with an increase of air temperature was related to morphological changes that occurred during drying and affected the shape of particles, surface structure, etc. The experiments proved that air/liquid ratio for two-fluid atomization and gas temperature were the most decisive factors controlling drying and degradation process rate and final product properties.     

喷雾干燥方式对粉末橡胶结构和性能的影响

采用热空气和过热蒸汽喷雾干燥法制备粉末橡胶,并对其结构和性能进行研究。结果表明:与热空气喷雾干燥制得的粉末橡胶相比,过热蒸汽喷雾干燥制得的粉末橡胶表面存在些许分布均匀的微孔,相对分子质量保持较好,硫化胶的物理性能相当,气密性较好。     

Spray Drying Tower Experiments

Abstract

The article presents a full set of spray drying experiments for selected products performed in a co-current spray drying tower developed at Lodz Technical University. The experiments enabled identification of process and atomization parameters (feed properties, feed rate and feed temperature, drying agent temperature, air flow rate, atomization ratio, etc.) on drying and degradation kinetics, spray structure, particle residence time, and final product properties. Drying agent temperature measurements showed, in all cases, the initial increase of gas temperature in the spray envelope caused by the spray expansion and then a decrease induced by liquid evaporation and heat losses to the environment. PDA analysis confirmed that the initial velocity of particles was a function of a diameter and also the function of the distance from the axis. Practically an identical particle size distribution was observed in each cross-sectional area of the dryer. Negative values of particle velocity in the vicinity of the axis and at the edge of the spray envelope were found which proved that recirculation of particles appeared in the column. Analysis of final product properties showed that for agglomerate-like materials a decrease of bulk density with an increase of air temperature was related to morphological changes that occurred during drying and affected the shape of particles, surface structure, etc. The experiments proved that air/liquid ratio for two-fluid atomization and gas temperature were the most decisive factors controlling drying and degradation process rate and final product properties.     

亚麻胶的喷雾干燥技术

研究了亚麻胶水溶液的各种喷雾干燥特性（工艺）。试验结果表明离心喷雾干燥为最佳的亚麻胶干燥方法。干燥产品具有粘度高,色泽好,颗粒均匀,流动性好,溶解性好等特点。     

大型喷烘两用喷漆室的工艺设计

以大型钢结构、塔筒等工件的后处理设备中喷烘两用喷漆室的设计为例,介绍了喷漆、烘干状态下的工艺设计,并通过合理的设备和系统配置大幅度地减少了电力安装容量,降低了设备投资成本和运行成本。     

喷雾干燥技术及装置

喷雾干燥是处理溶液、悬浊液或泥浆状物料的干燥器,对于PVC糊树脂更是理想装置。本文介绍了1万吨/年PVC糊树脂用两种喷雾干燥器。     

Powder Properties and System Behavior during Spray Drying of Bauhinia forficata Link Extract

This article presents a study of the effects of the spray-drying conditions on product properties and dryer performance during manufacture of dried extracts of Bauhinia forficata. The product properties (loss on drying of the dried extract, flavonoids degradation ratio, product size distribution, bulk and loose densities, powder morphology) and the equipment performance were determined as a function of the input parameters (dryer inlet temperature, ratio between the feed flow rate of the extract to the dryer evaporation capacity, and feed flow rate of the drying gas). Regression equations correlating powder characteristics and dryer behavior to input process parameters were obtained. The results demonstrate significant impact of the processing conditions on product properties and dryer performance. The loss on drying is a key property, since low values are demanded for the acceptance of the dried extract. In general, due to strict product specifications, the drying conditions that give an end product with the required quality are not associated with the optimal drying performance.     

喷雾干燥的研究进展

介绍了国内外喷雾干燥领域的最新研究进展,阐述了喷雾冷冻干燥、超临界喷雾干燥等方面的研究结果,探讨了关于喷雾干燥过程数学模拟的研究方法和结论,总结、归纳并提出了目前国内外较新的关于喷雾干燥的研究课题和方向。     

Powder Properties and System Behavior during Spray Drying of Bauhinia forficata Link Extract

This article presents a study of the effects of the spray-drying conditions on product properties and dryer performance during manufacture of dried extracts of Bauhinia forficata. The product properties (loss on drying of the dried extract, flavonoids degradation ratio, product size distribution, bulk and loose densities, powder morphology) and the equipment performance were determined as a function of the input parameters (dryer inlet temperature, ratio between the feed flow rate of the extract to the dryer evaporation capacity, and feed flow rate of the drying gas). Regression equations correlating powder characteristics and dryer behavior to input process parameters were obtained. The results demonstrate significant impact of the processing conditions on product properties and dryer performance. The loss on drying is a key property, since low values are demanded for the acceptance of the dried extract. In general, due to strict product specifications, the drying conditions that give an end product with the required quality are not associated with the optimal drying performance.     

喷雾干燥的计算机模拟

对喷雾干燥的计算机模拟计算进行了初步探讨,用FORTRAN语言编制了程序,对喷雾干燥过程进行了总体衡算和微元衡算,使计算快速、准确,而且便于程序与数据管理,结果表明,计算机完全可以替代人工手算.     

The Spray Drying of Food Flavors

Abstract

Spray drying is the most commonly used technique for the production of dry flavorings. In spray drying, an aqueous infeed material (water, carrier, and flavor) is atomized into a stream of hot air. The atomized articles dry very rapidly, trapping volatile flavor constituents inside the droplets. The powder is recovered via cyclone collectors. Flavor retention is quite satisfactory if dryer operating parameters are properly chosen. Flavor retention is maximized by using a high infeed solids level, high viscosity infeed, optimum inlet (160–210°C) and high exit (>100°C) air temperatures, and high molecular weight flavor molecules. The shelf life of oxidizable flavor compounds is strongly influenced by the flavor carrier.     

Spray Drying of Raisin Juice Concentrate

Raisin juice concentrate is a natural sweetener in syrup or paste form and it is produced from second-grade dry raisins by leaching them with water. Dried raisin juice, although is easier to handle and has more potential applications than the syrup, is not available in the market. In the present study, raisin juice powder was produced with a lab-scale spray dryer. The problem of stickiness in the drying chamber was overcome through the use of 21 DE, 12 DE, and 6 DE maltodextrins as drying aid agents. For each type of maltodextrin, the dryer operating conditions and the minimum concentration of maltodextrin in the feed, necessary for successful powder production, were determined. The maximum ratio of (raisin juice solids)/(maltodextrin solids) achieved was 67/33 and was made possible with the use of 6 DE maltodextrin. The inlet and outlet drying air temperatures were 110 and 77°C respectively, while the feed contained 40% w/w total solids. The physical and sensory properties of all powders produced were determined and found to be satisfactory, the only exception being their high hygroscopicity.