三聚氰胺装置干燥系统的工艺设计

对干燥系统操作条件的确定、设备选择及工艺设计原理进行了分析，论述了经常出现的问题及其原因所在，并提出解决方案，使干燥系统的操作尽可能稳定。     

三聚氰胺装置干燥系统的工艺设计

对干燥系统操作条件的确定、设备选择及工艺设计原理进行了分析,论述了经常出现的问题及其原因所在,并提出解决方案,使干燥系统的操作尽可能稳定。     

各种过滤器在三聚氰胺装置中的应用

本文介绍了三聚氰胺装置中所有过滤器的类型和工作原理，通过对装置过滤器的了解，为我们的安全操作提供了有力的保障。     

氢气作为热泵干燥装置干燥介质的分析

分析了氢气作为热泵干燥装置干燥介质时,干燥介质与物料的对流换热系数、对流传质系数、干燥介质的流动阻力、单位体积干燥介质与水蒸气的饱和混合物中的水蒸气量、单位体积干燥介质在绝热干燥过程中的最大水蒸气吸收量等特性,并与空气作为干燥介质时进行了对比,为氢气型热泵干燥装置的开发提供了较好的参考.     

热泵干燥装置中干燥介质的物性及其应用分析

在热泵干燥装置中,干燥介质对干燥过程的传热传质速率、物料干燥质量和装置的能源效率均具有重要影响。给出了空气、氮气、二氧化碳、氩气、氢气、氦气六种干燥介质的热物性数据及其计算方程,并分析了其适宜的应用场合,为热泵干燥装置中选择适宜的干燥介质提供了较好的参考。     

三聚氰胺生产装置OAT过滤器的改进

介绍了三聚氰胺装置OAT过滤器的工艺流程及其结构特点，分析了过滤器的小车转轴、拉杆定距管、振荡器空气出口管和滤叶滤网存在的问题，提出了相应的改进措施，实施后，取得明显效果，保证生产的正常进行。     

三聚氰胺装置氨回收系统的操作和调节

对影响氨回收系统操作的主要因素进行了分析,提出了通过保证物料平衡、调整回流比和进料状况等方案来稳定氨回收系统,并提出了调节产品质量方法和操作优化建议,使氨回收系统运行达到最大可能稳定性。     

三聚氰胺装置中氨回收工艺设计

1 高压法三聚氰胺生产工艺流程 利用尿素在高温高压下热解成三聚氰胺,急冷成粗三聚氰胺溶液,然后经结晶器成为三聚氰胺料浆的物料送入离心机,分离为固相的湿三聚氰胺和液相的母液,固相的湿三聚氰胺进一步干燥生成为成品三聚氰胺。液相的母液送入氨回收系统,回收其中的氨后,通过OAT结晶工段将其中的OAT几乎全部析出,再经过OAT过滤器,分离为滤饼和滤液,滤饼废弃,     

热泵干燥装置的特性方程及其应用分析

以应用最广泛的封闭式热泵干燥装置为例,建立了其SMER计算方程。在此基础上,对SMER随干燥器进口空气温度、干燥器出口空气温度和蒸发器出口空气温度而变化的规律进行了计算和分析。结果表明,其他两个参数一定时,SMER随干燥器出口空气温度上升而降低,随蒸发器出口空气温度上升而增加,但当干燥器进口空气温度取适宜值时,SMER存在最大值。     

高压法三聚氰胺装置超滤系统的应用

介绍了高压法三聚氰胺装置中超滤系统的工艺特点,对其在应用中所存在的有关问题进行了分析,并介绍了所实行的相应的处理措施,这些措施有利于超滤系统的稳定运行.     

Simultaneous Granulation and Drying of Filter Cake

There are normally two possible routes for converting a wet cake obtained from a filter or centrifuge into a granular end product: drying followed by mechanical compaction; wet granulation followed by drying. A third way, simultaneous granulation and drying, has been investigated and has been in use now for several years for the production of a granular end product. It has the following advantages over wet granulation followed by drying: the process is able to accommodate a wide range of moisture contents and the bulk density of the end product is higher. The advantages over drying followed by mechanical compaction are the need for only one process step and the superior shape of the particles (more spherical, less sensitive to attrition).     

三聚氰胺甲醛／聚乙烯复合层压板生产工艺

介绍了以纸基三聚氰胺甲醛（ＭＦ）塑料为面层、废旧聚乙烯（ＰＥ）塑料为芯层,用层压工艺制造复合板材的工艺过程,并重点论述了阻燃型板材的配方设计及工艺控制。     

6 000 t/a三聚氰胺装置扩能技术改造

介绍了6 000 t/a常压气相淬冷工艺三聚氰胺装置扩能改造,分析了扩能改造中关键设备包括液尿冷却及输送、反应器、载气压缩、热气冷却、热气过滤、结晶、包装及副产液氨系统存在的问题,确定了相应的改造方案,改造后生产能力达到8 000 t/a,降低了生产成本。     

Fuzzy Control System in Drying Process of Fermented Sausages

Abstract

Fermented sausages are dried in artificial driers, where the air relative humidity (RH) and temperature (T) are controlled. On the basis of product evaluation, an expert manually readjusts the RH set points in a staggered form. The main drawbacks of this control system are the discontinuity of the product evaluation and the cost of the experts' training. This study proposes a system to readjust the set points of RH based on the theory of fuzzy sets. Two fuzzy control systems were applied to the drying process of fermented sausages in an industrial drier at constant temperature. They used different on-line instrumental measurements related to the expert evaluation as input variables. Results show that fuzzy control can improve the manual control system and it helps quality assurance during the drying process. It reduces the risk of crust development, one of the most serious problems in fermented sausages.     

Mechanical Dewatering and Thermal Drying of Sludge in a Single Apparatus

This article describes the Centridry® technology (marketed in the UK by Euroby Ltd.) used at the Monsanto wastewater treatment plant in Antwerp, Belgium, for handling excess wastewater-activated sludge. In one single enclosed machine, sludge with an initial solids concentration of 1.5 to 4% w/w dry substance is mechanically dewatered with a high-solids decanter centrifuge and thermally dried in a flash dryer, yielding a final product with a concentration of solids ranging from 80 to 95% w/w dry substance. Operational experience with varying sludge characteristics affecting the fouling sensitivity of the system is presented for the Centridry technology at the Monsanto plant in Antwerp.     

GPR System for Monitoring Paddy Moisture Content in a Drying Process

High-frequency ground penetrating radar (GPR) was used in this study to monitor the moisture content of paddy in a drying process. The reflected radar pulses were used to calculate the dielectric constant of paddy. Owing to the temperature increase, Nelson and Noh's quadratic model was extended by introducing a temperature correction factor adapted to predict the dielectric constants at different temperatures. The calculated paddy moisture content was in good agreement with the values measured by the conventional oven method. Our results demonstrate the potential use of GPR systems as an online tool for monitoring the paddy moisture content in the drying process.     

Process Drying Practice

In this investigation, the air drying characteristics of fresh and osmotically pre-treated pineapple slices in a tray dryer were studied under different operating conditions. The air velocity varied from 1.5 to 2.5 m/s and the air temperature from 40 to 70°C. The analytical solution of the second Fick's law for an infinite slab was used to calculate effective diffusion coefficients and their temperature dependence could be well represented by an Arrhenius-type equation. Comparison of the results showed that the diffusion coefficients were lower for the pre-treated fruit. By means of automatic control, it was possible to obtain drying curves under conditions of constant product temperature, which showed to be an alternative to reduce the drying time of pineapple slices.