旋转闪蒸干燥技术在分子筛制备中的应用与改进

介绍了旋转闪蒸干燥的原理、特点及其在分子筛干燥过程中的应用。针对生产中存在物料粘壁和堵塔等问题进行了分析。通过对设备内部结构的研究,发现风量、环隙口风速、混合室风速、空床风速、布袋除尘风速以及倒锥体尺寸的设计偏差是导致上述问题的主要原因。经过设计参数优化和设备改造,提高了物料的干燥效率,彻底解决了干燥工序中存在的诸多问题。该技术的成功实施对于旋转闪蒸干燥技术在其他化工领域的应用也有很好的借鉴作用。     

旋转闪蒸干燥器在碳酸钡干燥中的应用

介绍了河北诺达化工设备有限公司开发生产的旋转闪蒸干燥器代替回转圆筒干燥器在碳酸钡干燥过程中的应用.通过对投资、能耗、产品质量、环保效益的详细分析得出结论:用旋转闪蒸干燥器代替回转圆筒干燥器,具有节省投资,节约能耗,提高产品质量,减小环境污染等优势,为碳酸钡的干燥提供了一种新方法.该设备也适用于碳酸锶、硫酸钡、碳酸钙等滤饼类物料的干燥,同样对于冶金、化工、医药、食品等行业的滤饼类物料的干燥也具有极高的应用价值.     

Hot air drying of purple-fleshed sweet potato with contact ultrasound assistance

A drying technique using a combination of a contact ultrasound apparatus and a hot air dryer is developed to investigate the strengthening effect of contact ultrasound on hot air drying. The effects of drying parameters such as ultrasound power and drying temperature on drying characteristics, effective moisture diffusivity (D_eff), microstructure, glass transition temperature (T_g), rehydration ratio, and color difference are discussed. The results show that the application of contact ultrasound causes a significant acceleration of internal mass transfer, and higher ultrasound power applied leads to faster drying rate. The effect of ultrasound power on drying rate decreases along with the reduction of moisture content during drying process. The increase in drying temperature significantly reduces drying time but has a little negative influence on the strengthening effect of ultrasound. D_eff values range from 1.0578?×?10^?10 to 5.4713?×?10^?10?m²/s in contact ultrasound-assisted hot air drying of purple-fleshed sweet potato and increase significantly with an increase in drying temperature as well as ultrasound power. The microstructure of purple-fleshed sweet potato is greatly different at different ultrasound powers during contact ultrasound-assisted hot air drying and shows more microchannels and dilated intercellular spaces in the cross-section of purple-fleshed sweet potato micrographs at higher ultrasound power. Contact ultrasound application during hot air drying could improve the mobility of water and consequently reduce glass transition temperature. Lower color difference and higher rehydration ratio could be achieved as drying temperature decreases and ultrasound power increases. The increase in contact ultrasound power could reduce energy consumption of drying process up to 34.60%. Therefore, contact ultrasound assistance is a promising method to enhance hot air drying process.     

Characterization of extruded film based on thermoplastic potato flour

Potato flour is abundant and less expensive than starch, though its major component is starch. It would therefore seem to be an attractive and viable source of biomass for biodegradable thermoplastic products. This study prepared thermoplastic potato flour (TPF) and thermoplastic potato starch (TPS) films by extrusion and investigated their properties. A mixture of glycerol and triethyl citrate (25−35% of total weight) was chosen for the plasticizer. Properties of the TPF film, such as mechanical properties, surface hydrophilicity, surface energy, moisture sorption isotherm, and glass transition temperature (T_g), were characterized and compared with TPS film. The results showed that TPF film was comparable to TPS film in many properties. The mechanical properties of the TPF film, including tensile strength, elongation at break, and tensile modulus, were similar in magnitude to TPS film. In addition, TPF film showed lower T_g and surface hydrophilicity, but higher surface wetting capacity than TPS film. Components other than starch in potato flour were believed to have had a plasticization effect on TPF properties. Overall, potato flour demonstrated a comparable capacity for manufacturing thermoplastic film similar to the more expensive starch feedstock. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Effects of pretreatments on properties of microwave-vacuum drying of sweet potato slices

Abstract

Pretreatments of blanching (BL); osmotic dehydration at 35°Brix of sucrose (OD); ultrasound in distilled water (UD), and ultrasound-assisted osmotic dehydration (UO) were carried out for microwave-vacuum drying (MVD) orange- and purple-flesh sweet potato slices, and effects on their properties were investigated in this study. UO had improvements effects on water loss, solid gain, and relaxation time of the samples compared to other pretreatments. Low-field nuclear magnetic resonance results offered a view of water state concerning the effects of different pretreatments on sweet potato. UD treatment following by BL showed a long relaxation time corresponding to the weaker degree of bound hydrogen proton or the greater freedom degree of hydrogen comparing to other pretreated samples. Differential scanning calorimetry parameters appeared to be sensitive to pretreatments by increased Tg value compared to blanched sample. The value of Tg shows that it does not depend only of the water content but also on the experimental conditions (pretreatments). The dried sweet potato exhibited amorphous structures as evidenced by the X-ray diffractograms due to the BL treatment and MVD. Concentration of total phenolics and anthocyanins were high in purple sweet potatoes, whereas content of vitamin C and total carotenoid were high in orange ones. Application of UO is suitable for retention of bioactive compound and stability of MVD sweet potato slices.     

闪蒸干燥技术在白炭黑生产中的应用

通过采用闪蒸干燥技术,对原白炭黑生产中的干燥设备进行了改造,对改造前后的效果进行比较,阐述了闪蒸干燥技术的特点。     

一种快干型水性复膜胶的研制与应用

复膜胶是将聚丙烯或聚酯膜与纸制品复合在一起的胶粘剂。目前国内市场的复膜胶多为含有易燃、易爆、有毒和污染环境的有机溶剂型复膜胶,水性复膜胶主要存在干燥时间长、冬天不能干透和长时间达不到应有挺度等缺陷。通过种子半连续聚合法,优化制备乳液的单体配比,引入特种交联剂A-12(自制)和用部分乙醇替代溶剂水,在乳液的种子聚合阶段加入松香打底,制备出一种快干型水性复膜胶。讨论了软、硬单体配比、乳化剂和交联剂用量、玻璃化转变温度和反应温度对剥离强度的影响。该复膜胶固含量为(45±1)%,粘度为150～300 mPa.s,pH值为6～7,可密闭存放6～12个月,剥离强度为0.51kN/m,干燥时间为5～10 min(春夏季节)和10～20 min(秋冬季节)。     

Evaluation of new parboiled rice process using humidified hot air fluidized bed drying

This study aims to experimentally investigate the drying characteristics and quality of a paddy dried by hot air (HA) and humidified hot air (HHA) fluidization technique. Qualities such as head rice yield (HRY), white belly, degree of gelatinization (DSG), and color of dried paddy were evaluated. A paddy with an initial moisture content of 14% d.b. was soaked in hot water at a temperature of 70?°C for 5?h then dried at a temperature of 130,150, and 170?°C, relative humidity in the range of 0.3–12%, an air velocity of 3.9 m/s, and a bed height of 10?cm. The results showed that the drying time of the paddy in the HHA condition took longer than the HA drying condition. Because HHA provided a higher grain temperature and a slow rate of drying, the degree of starch gelatinization was significantly higher when compared to HA. The subsequent HRY was relatively higher than using HA drying. However, the color of the sample obtained from the HHA condition was relatively browner, but the parboiled rice product still had a light brown color for the drying temperature range used in this study. To produce parboiled rice, HHA could be operated up to the temperature of 170?°C, relative humidity of 6%, and DOM of 10%.     

干燥技术的进展和应用

文章侧重与化学工业关系较密切的方面，以各种干燥机的开发、改进和应用为主要线索，简要评述干燥技术２０多年来的进展与应用、技术发展趋势和存在的问题、以及我国的基本情况。     

Studies on the grafting of acryloylated potato starch with styrene

An investigation of graft polymerization to determine the potential of a starch‐bonded acryloyl group as a suitable coupling agent with vinyl monomers was carried out. In this case, potassium persulfate was used as a free‐radical initiator using water as the reaction solvent for further graft polymerization. This work revealed the ability of water as a reaction medium; perhydroxyl and hydroxyl radicals were easily formed from persulfate to produce free radicals to activate the styrene monomer towards grafting with acryloylated potato starch. The graft copolymers were characterized by FT‐IR spectroscopy and further confirmed using saponification. The analysis results showed the grafted potato starch with the styryl chain afforded protection to the ester bond, which resisted the alkaline hydrolysis. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 452–459, 2005     

Optimization of the microwave drying process for potato chips based on the measurement of dielectric properties

A microwave drying system with functions of automatic power and temperature control was developed to dry potato chips. The mass and moisture content of the sample are available online. The dielectric properties of the samples were measured during microwave drying, during which the microwave absorption capacity of the samples was analyzed. Afterward, a reasonable power and temperature control scheme was formulated. The enhanced microwave drying technology of potato chips is found by comparing product quality under different schemes. Results show that the change in the dielectric properties of materials during microwave drying is closely related to moisture and temperature variations. A three-stage different temperature control with predefined variable power profiles resulted in the best product quality.     

微波干法制备醚化淀粉絮凝剂及其应用

以玉米淀粉为原料,2,3-环氧丙基三甲基氯化铵为醚化剂,采用微波干法制备醚化淀粉絮凝剂,通过正交试验优化了醚化淀粉絮凝剂制备工艺条件,考察了醚化淀粉絮凝剂用量、pH值及反应时间对生活污水脱色率的影响.结果表明,在pH值为6,50 mL生活污水中加入0.7 g醚化淀粉,保持搅拌2 min,脱色率可达94.2％.微波干法制...     

Optimization of Drum Drying Parameters for Low Amylose Rice (KDML105) Starch and Flour

An attempt was made to study and model the effects of drum drying process variables on the physico-chemical properties of low amylose rice (KDML105) flour and starch. Drum surface temperature, holding time and solid content of the slurry were varied at three levels: 115-135°C, 14-84 s and 20-40%, w/w, respectively. The dependent variables were moisture content (MC), degree of gelatinization (DG), water absorption index (WAI), water solubility index (WSI) and pasting property. High solid content led to a decrease in DG, WAI and initial peak viscosity (IPV) and increase in WSI of dried samples. Longer holding time resulted in increased DG while surface temperature had no significant effect on all characteristics. Predictive correlations were developed using stepwise multiple linear regression to predict MC, DG, WAI, WSI, and IPV of dried products from drum drying variables.     

冷法H_2O_2氧化制备马铃薯淀粉粘合剂及改性研究

在室温下,以马铃薯淀粉为原料,双氧水为氧化剂,制备出了马铃薯淀粉粘合剂.探讨了氧化剂用量、催化剂用量、糊化剂用量、氧化时间、糊化时间、粉水比、络合剂用量对粘合剂性能的影响,以粘度和初粘力为评价指标,通过L18(37)正交试验确定制备淀粉粘合剂的最佳条件为:m(水)∶m(马铃薯淀粉)=5∶1,双氧水1.3 mL,硫酸亚铁0.2 g,NaOH为3.0 g,氧化时间90 min,糊化时间30 min,硼砂0.3 g.并以添加聚乙烯醇进行接枝改性,提高其干燥时间和初粘力,实验得到添加量为5%时效果最好.     

Optimization of Drum Drying Parameters for Low Amylose Rice (KDML105) Starch and Flour

Abstract

An attempt was made to study and model the effects of drum drying process variables on the physico–chemical properties of low amylose rice (KDML105) flour and starch. Drum surface temperature, holding time and solid content of the slurry were varied at three levels: 115–135°C, 14–84 s and 20–40%, w/w, respectively. The dependent variables were moisture content (MC), degree of gelatinization (DG), water absorption index (WAI), water solubility index (WSI) and pasting property. High solid content led to a decrease in DG, WAI and initial peak viscosity (IPV) and increase in WSI of dried samples. Longer holding time resulted in increased DG while surface temperature had no significant effect on all characteristics. Predictive correlations were developed using stepwise multiple linear regression to predict MC, DG, WAI, WSI, and IPV of dried products from drum drying variables.     

冷制高强快干淀粉胶粘剂

介绍了一种以淀粉为主要原料,在复合催化剂作用下,经双氧水室温氧化并添加高强快干添加剂和其他助剂,制备高强快干淀粉胶的方法,讨论了对淀粉胶性能的影响因素及其简要的作用机理,确定了能够满足最佳上机要求的配方。应用本方法制出的胶粘剂,通过中试制板,证明该胶具有干燥速度快、强度高等优点。     

高取代度酯化淀粉的制备与工艺研究

采用有机溶剂法制备高取代度淀粉琥珀酸酯。以琥珀酸酐为酯化剂,对淀粉进行酯化改性。经单因素试验法得到淀粉琥珀酸酯的制备条件,采用正交试验法研究淀粉琥珀酸酯制备的最佳工艺条件：反应温度50℃,反应时间5 h,每克活化淀粉催化剂用量1 m L,活化淀粉与酸酐分子的摩尔比为1∶3。在最佳制备条件下,制得取代度为0.40的淀粉琥珀酸酯。     

不同混凝剂对马铃薯淀粉废水混凝效果的影响

用混凝剂Fe2(SO4)3、PAC、PFSS、PAFC处理马铃薯淀粉废水,研究了混凝剂的种类、投药量、废水pH值、助凝剂PAM的投加量以及沉降时间等对混凝效果的影响。结果表明,混凝沉淀法预处理马铃薯淀粉废水优选混凝条件为:pH为7,混凝剂PAFC为1 200 mg/L,助凝剂PAM为5 mg/L,沉降25 m in。在此条件下,废水的浊度、COD去除率分别达97.27%及40.55%。投药量明显减少,而沉积物产量较高,为后续生化处理提供了有利条件。     

Synthesis and electrorheology of potato starch phosphate

Potato starch phosphate (PSP) particles were synthesized via an esterification process of potato starch with a mixture of various concentrations of phosphoric acid and urea. The electrorheological (ER) characteristics of the synthesized PSP particles, suspended in a silicone oil, were examined. The PSP granule‐based ER fluid exhibited typical ER behavior, possessing a nonvanishing yield stress under an applied electric field. Enhanced polarization and higher yield stresses were observed as the content of phosphate groups in the starch increases. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1770–1773, 2004     

Multiphase dynamic flash simulations using entropy maximization and application to compressible flow with phase change

A isochoric‐isoenergetic flash solver using a direct entropy maximization principle for phase splitting and Gibbs free energy minimization for phase stability is developed. The solver searches for the global stable state in a rigorous and thermodynamically consistent way. The solver is demonstrated to be robust and efficient to handle multiphase flash, even in the vicinity of phase boundaries. Dynamic flash computations and gas dynamics simulations of shock waves are considered for pure ethylene and for binary ethylene‐nitrogen mixtures. The simulations show significantly different shock wave characteristics when phase separation is considered due to intensive energy exchange, compared to the frozen flow limiting single‐phase solution. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3013–3024, 2014