PVC干燥系统的运行优化总结

介绍了气流-旋风干燥工艺和沸腾干燥床工艺在PVC生产中的运行情况,以及气流一旋风干燥工艺和沸腾干燥床工艺改造情况.     

新型沸腾煅烧干燥技术在纯碱行业的开发与应用

阐述一种以“新型结构的沸腾干燥床”配套不同的生产工艺生产轻质纯碱和重质纯碱的专利技术。并从设备、工艺、投资、运行稳定性、主要技术经济指标等方面分别与轻灰回转干燥技术和重灰回转干燥技术及国外引进的沸腾流化技术进行对比分析,特别是该技术用于重质纯碱生产的比例将会逐步加大,目前在新建、扩建和搬迁的许多纯碱厂已采用。     

PVC树脂干燥生产工艺比较

本文介绍了大沽化工厂原有生产ＰＶＣ的内热沸腾干燥工艺的不足,并通过对原有民运行过程分析,采取了改进措施,分析了新旋风干燥装置的优点。     

强化沸腾干燥工艺设计

介绍了强化沸腾干燥工艺设计的步骤，重点讨论了工艺计算。     

PVC干燥工艺的优化

采用卧式沸腾干燥床干燥PVC,介绍了干燥工艺过程,针对PVC干燥系统出现的问题提出了改造措施。     

心宝丸沸腾干燥工艺研究

目的:优选并确立心宝丸的最佳沸腾干燥工艺。方法:以心宝丸的水分、外观、溶散时限为考察指标,采用L_9(3~4)正交试验法对心宝丸沸腾干燥过程中可能影响心宝丸水分、外观和溶散时限的进风温度、物料温度、干燥时长3个因素进行研究。结果:心宝丸的最佳沸腾干燥工艺:进风温度90℃,物料温度55℃,干燥10.5 h。结论:本试验采用正交试验法对心宝丸的沸腾干燥工艺进行试验,工艺稳定,重现性好,为制备心宝丸的最佳沸腾干燥工艺。     

大型氯化铵沸腾干燥系统

阐述了氯化铵沸腾干燥原理,开发出了大型氯化铵沸腾干燥系统。大型氯化铵沸腾干燥系统的优点和存在的问题。     

强化沸腾干燥装置

强化沸腾干燥装置是我厂近年在综合多种气流沸腾干燥设备长处的基础上设计而成的。经过几年的使用和不断改进,于1991年8月通过了省级鉴定。该装置的主要技术指标达到了国内同类产品的先进水平,现已投入批量生产。     

沸腾干燥装置在活性炭生产中的应用

本文介绍了沸腾干燥装置的工艺流程和设计计算。结果表明，对于粉状活性炭，沸腾干燥装置是一种理想的干燥设备。     

沸腾干澡装置在活性炭生产中的应用

本文介绍了沸腾干澡装置的工艺流程和设计计算。结果表明，对于粉状活性炭，沸腾干燥装置是一种理想的干燥设备。     

小型化卧式振动流化床干燥系统的研制

分析了变性淀粉工业生产所用的气流干燥装置不能用在中试或者高校实验的原因,同时叙述了变性淀粉干燥设备应具备的条件及选择卧式振动流化床干燥作为中试用变性淀粉干燥装置的原因。设计了变性淀粉中试用小型化卧式振动流化床干燥系统的工艺设计方案,通过纯胶这种新型的变性淀粉进行干燥,从而验证了小型化卧式振动流化床干燥系统可行性及实用性。     

流化床干燥聚碳酸酯小试实验研究

使用流化床小试装置对聚碳酸酯粉料进行干燥,绘制聚碳酸酯干燥速率曲线,初步证明了卧式流化床干燥聚碳酸酯具有一定的可行性。     

Microwave-Assisted Atmospheric Freeze Drying of Green Peas: A Case Study

Atmospheric freeze drying (AFD) is based on the sublimation of ice due to a pressure gradient (convective drying), and is a dehydration process for temperature-sensitive products. Since the process is slow in general, microwave radiation (MW) was applied in order to increase the sublimation in fluid and fixed bed conditions at drying temperatures of ?6°C, ?3°C, and 0°C. The modified Weibull model was used to describe the drying behavior for all investigations. With 280 Watt power supplied to the magnetrons, it was possible to reduce drying time by approximately 50%. The drying efficiency was approximately 30%, while the SMER was increased by 0.1 to 0.3 kg_waterkWh^?1, which gives better energy efficiency for the microwave drying system used in this investigation. The product quality (color reduction and particle size/porosity) was well preserved in fixed bed drying at ?6°C and ?3°C, while the product quality was reduced significantly in microwave AFD experiments at 0°C and in a fluid bed. The drying rates of AFD in a fluid bed condition were not as high as those in a fixed bed. MW-AFD in a fixed bed condition at temperatures of ?6°C and ?3°C performed best regarding product quality, drying time, and process control.     

DRYTNG OF PEPPER SEEDS USING A COMBINED MICROWAVE/FLUIDIZED BED DRYER

Abstract

The drying rates curves in terms of moisture content versus elapsed drying time for white pepper seeds were obtained experimentally using a fluidized bed and a combined microwave/fluidized bed. The combined microwave/fluidized bed employs a microwave field to assist convective drying. For both procedures, the drying rates were found to be dependent on the inlet air temperature and velocity. Significantly improved drying rates were achieved utilized a combined microwave/fluidized bed drying compared with a conventional fluidized bed.     

过氧化二异丙苯（DCP）的干燥特性与干燥工艺研究

近几年,我国过氧化二异丙苯（DCP）的产量一直处于世界首位,干燥工艺是DCP生产中的一个很重要环节。分析了高桥石化DCP干燥生产工艺的发展和延续,介绍了DCP的干燥特性和工艺特点,以及采用卧式多室流化床干燥机的优势。     

湿污泥颗粒的流化床干燥实验及模型

在鼓泡流化床内以河砂为干燥介质,对单颗粒湿污泥的流态化干燥特性进行实验研究,得到了流化床温度、污泥初始水分、污泥粒径及流化速度对干燥速率的影响规律：流化床温度及污泥粒径对干燥速率的影响都呈指数规律;污泥的水分越大,干燥速率越大;在鼓泡流化床流化速度达到2倍临界流化速度以上时,充分流化,流化速度再增大(2~5倍临界流化速度)对干燥速率没有明显影响. 在基本的扩散传质理论的基础上,利用实验数据回归得到湿污泥在鼓泡流化床内干燥的半经验模型,为流化床污泥干燥器的设计提供了基础数据和依据.     

Simulation and Validation of Microwave-Assisted Fluidized Bed Drying of Soybeans

A general mathematical model of heat and mass transfer was developed to simulate the microwave-assisted fluidized bed drying of bulk grain. The model was solved using the well-known Runge-Kutta-Gill method. The model is capable of predicting the moisture content of soybean as well as the drying air parameters (i.e., drying air temperature and moisture content) during drying. The values of mean relative deviation (MRD) were less than 8 and 10% for prediction of grain moisture content and outlet air parameters, respectively, which reflects an acceptable accuracy. In comparison with conventional fluidized bed drying of soybean, microwave-assisted fluidized bed drying led to 83.39–98.07% savings in drying time and 82.07–95.22% savings in specific energy consumption when reducing soybean moisture content from 18.32 to 12% (db).     

Measurement of constant drying rate of wet material placed in a fluidized bed of inert particles under reduced pressure

The objective of this study is to estimate the drying characteristics of a relatively large material immersed in a fluidized bed under reduced pressure by measuring the constant drying rate. The constant drying-rate period in a fluidized bed under reduced pressure is difficult to measure because it is extremely short. To maintain the constant drying-rate period, distilled water is directly supplied to the drying material. Through our experiment, the heat transfer coefficient of the material surface was also determined. The results were compared with data on hot air drying. The constant drying rate is higher for fluidized bed drying than for hot air drying. It suggests that the heat transfer coefficient on the surface of the drying material is much larger for fluidized bed drying than for hot air drying. For fluidized bed drying, the effect of pressure in the drying chamber on the heat transfer coefficient is slight at the same normalized mass velocity of dry air (G/G_mf). The temperature difference between the inside of the drying chamber and the drying material is much smaller for fluidized bed drying than for hot air drying. The constant drying rate increases as the pressure in the drying chamber decreases.     

Batch drying kinetics of corn in a novel rotating jet spouted bed

The batch drying kinetics of corn as a test material were investigated experimentally in a novel rotating jet spouted bed (RJSB) using both continuous and intermittent (on/off) spouting and heating schemes. The parameters investigated include inlet air temperature, bed height, superficial air velocity, nozzle diameter, distributor rotational speed and intermittency of spouting and heat input. The results indicate that the drying kinetics are comparable with conventional spouted and fluidized beds for slow drying materials and that intermittent drying can save up to 40% of the thermal energy as well as air consumption with better quality product.     

Drying Characteristics of Carrots Immersed in a Fluidized Bed of Fluidizing Particles Under Reduced Pressure

The drying characteristics and properties (color and shrinkage) of carrots (as a representative agricultural product) were experimentally examined in a fluidized bed under reduced pressure. Dry hot air and superheated steam were used as the drying gases. Rice and carrot powders (0.125–0.355 mm in diameter) were used as the fluidizing particles, in addition to glass beads (0.12 mm in diameter).

It was confirmed that the drying rate using a fluidized bed was much higher than without a fluidized bed (hot-air drying), regardless of the type of fluidizing particles used. Under reduced pressure, both with and without a fluidized bed, the drying rate was higher than that at atmospheric pressure using hot air. The drying rate was sufficiently high for fluidized-bed drying with superheated steam, though the drying rate was higher with hot air than with superheated steam. As the drying temperature increased, the volume ratio (befor/after drying) of the sample increased. At high drying temperatures (373 and 423 K in the present study), the color of the sample changed; in other words, a heat-induced change in the properties of the carrot was observed. At a low drying temperature (333 K in the present study), the drying method did not affect the color of the carrot; i.e., the color of the dried material was maintained even in a fluidized bed under reduced pressure when the drying rate was higher.