Research and Application of Wear Resistant Refractories for Cooling Zone of Large Scale Coke Dry Quenching Ovens

In order to prolong the service life of the cooling zone of large scale coke dry quenching ovens,six kinds possible refractories for the cooling zone of large scale coke dry quenching ovens： SiC containing brick A,SiC containing brick B,mullite-andalusite brick,spinel containing brick,zirconia containing brick,corundum-mullite brick and grade B mullite brick,were analyzed in properties. It is found that the cooling zone lining adopting SiC containing bricks or mullite-andalusite bricks has much longer service life. Based on this,a new type of wear resistant brick was developed. The brick has a compressive strength of 135 MPa,a wear loss of 2. 10cm^3（only a quarter of that of the grade B mullite brick）,and a higher bulk density than the grade B mullite brick. The application of the brick in a 140t·h^（-1）coke dry quenching oven showed that it performed better than the grade B mullite brick. The cooling zone adopting the new bricks has a lower coke discharging temperature,which is beneficial to the enhancement of heat recovery efficiency and steam power generation.

Optimization of process conditions for drying of catfish(Clarias gariepinus)using Response Surface Methodology(RSM)

Drying is applied to lower the moisture content of fish to a level that can prevent the growth of mould and infestation of micro-organism and thus minimizes microbial degradation.The goal of this work was to optimize the process conditions during electrical oven drying of catfish.Moisture content(MC)was quantitatively investigated during the drying process of catfish sizes using response surface methodology(RSM)to obtain minimum moisture content.The independent process variables for the drying process were temperature(50–70◦C),product thickness(10–20 mm),salt concentration(0–20%)and drying time(480–600 min.).Two factorial interaction(2FI)regression model describing the effects of independent drying process variables on the moisture content was developed.The effects of temperature and drying time were more pronounced for MC than the thickness and salt concentration.The optimum conditions were found to be temperature=63.43◦C,product thickness=14.81 mm,salt concentration=9.07%and drying time=600 min.At these optimum conditions,moisture content was found to be 2.64%w.b.Validation of experimental results with the empirical model was evaluated using coefficient of correlation(R2)which was found for the model equation as,R2=0.994.

Heparin Sodium Was Prepared from Pig Intestinal Mucosa by Dialysis and Spray Drying

A method to extract crude heparin sodium from pig intestinal mucosa by dialysis and spray drying was established. The pig intestinal mucosa was treated in the following steps: enzymolysis, resin exchange adsorption-washing, elution, pressure filtration, dialysis, spray drying. Activity of the product was measured using a heparin anti-IIa factor assay kit. The yield of crude heparin obtained by this method was 2.79% higher than that of oven drying method;the production of 1 kg crude heparin sodium saved 43.4 pigs small intestine. The activity was 98.48 ± 2.49 IU/mg (n = 5), 15.18 IU/mg higher than that obtained by oven drying method. The product is pale white powder, attractive color and easy to dissolve.

Optimization and Simulation of Inclined Channel Area Lining for CDQ Ovens

The mechanical force borne by the lintel and“brackets”in the inclined channel area of CDQ and the thermal stress generated by the top-down temperature gradient were simulated by ANSYS software.The following conclusions are drawn.(1)The mechanical force has very mild effect on the damage of the“brackets”.(2)The temperature gradient caused by the uneven temperature distribution of CDQ oven is the key factor affecting the“bracket”damage.The different expansion of refractory materials in various parts results in the thermal stress concentration which tears the“brackets”.(3)The structure adjustment of the“brackets”has very little effect on the thermal stress distribution.(4)The multi-phase nitride bonded silicon carbide for CDQ can effectively alleviate the stress concentration at the“brackets”,realizing the long-life and stable operation.

A Neural Based Modeling Approach for Drying Kinetics Analysis of Mint Branches and Their Fractions (Leaves and Stems)

This work is aimed at investigating regular mint (Mentha × villosa) drying behavior and assessing how the heterogeneous composition of plants affects their drying kinetics. Drying kinetics and sorption isotherms were evaluated for whole branches and their fractions (leaves and stems). Stems and leaves were characterized by measurement of dimensions, apparent density and initial moisture content. The moisture sorption isotherms were obtained under temperatures of 30°C, 40°C and 50°C for branches, stems and leaves and the data were fitted to the GAB model. Mint branches and their fractions were oven dried at temperatures from 40°C to 70°C?and were obtained kinetic curves for each part. Water sorption patterns were similar for leaves and stems and the GAB model described well the sorption behavior of both materials. At a constant temperature, the drying rates were higher for leaves in comparison to stems and the differences increased as the temperature was raised. Therefore, depending on drying conditions, the moisture distribution in dried branches might be significantly different. Since the leaves constitute the major fraction in branches, the drying rates of branches were closer to those of leaves. The kinetic curves were fitted to a diffusion model based on an analytical solution of Fick’s second diffusion law and to an empirical model based on artificial neural network (ANN). The results showed that the model based on the ANN predicted the drying kinetics of the different parts better than the diffusive model. A single network was built to describe the kinetic behavior of branches and fractions in the whole range of temperatures investigated. The diffusive model based on fitting effective diffusivity did not provide good predictions of moisture content, probably because neither the dependence of effective diffusivity on the moisture content nor the heterogeneity and shrinking of static beds were considered.

枸杞烘干箱温度场优化及仿真

目的:提高枸杞干制品品质。方法:采用标准Realizable k-ε湍流模型进行理论分析,利用Fluent软件仿真运算并结合实验验证,探究烘干室换热温度场分布规律,并对换热参数进行优化。以温度均匀性系数以及温度分布云图为评价标准,分析换热板入口流速、换热板流道宽度、换热板流道高度、换热板间距对烘干箱温度场均匀性的影响。结果:对烘干室结构参数进行优化后,温度云图显示出的高温区面积大且比较集中,两端和中间的温度梯度小。优化后的温度标准偏差比优化前降低了0.64%,模拟值与试验值的整体趋势大体相同,其误差值为2.56%。结论:枸杞烘干温度分布均匀性最佳的工艺条件为热水入口流速0.18 m/s,流道高度22 mm,流道宽度35 mm,换热板间距85 mm。

Development of a Novel Oven-Furnace

This research work is focused on the design and fabrication of Novel Oven-Furnace, using locally sourced materials for the purpose of carrying out drying and thermochemical treatments in accordance to the International Electric Equipment (IEE) regulations. Working drawings were produced, and mild steel sheet was used for the construction of the casing, while other materials for the construction were selected based on functions and properties of the materials, cost considerations and ease of fabrication into component parts. The design closely revealed the parameters and features of the furnace, but the control system was designed to function systematically as Oven and Furnace. Testing was carried out to evaluate the performance of the Oven-Furnace. From the result obtained, it was observed that the Oven-Furnace has fast heating rate which is comparable to rates of conventional brands of furnaces purchased from Germany or Canada. Unlike the ordinary furnaces, this equipment was designed to operate systematically to maintain constant temperature at any set temperature value. The lower cost of design of the Oven-Furnace coupled with its good heat retaining capacity, long estimated life time, uniform heating rate, controlled atmosphere, safety and ease of maintenance justifies the usage.

Design of ZigBee-WiFi Gateway for Vacuum Oven

In the process of power battery production, it is necessary to put battery into vacuum oven for drying, the temperature, the vacuum degree and other factors directly influence the quality of the power battery. In order to remotely control the temperature and vacuum degree of vacuum oven in the process of power battery manufacturing, the wireless communication system based on the ZigBee-WiFi gateway for the power battery production is presented. The system uses wireless module CC2530 as the core chip, to complete the machine networking in workshop, and use of WiFi wireless module ESP8266 to complete data interconnection ZigBee and WiFi network, implement the data information exchange and sharing between the vacuum oven and the Internet. This wireless communication system has the characteristics with easy networking, low power consumption and low cost. So, this communication system can meet the requirement of data transmission and sharing in power battery manufacturing and other production activities.

红外干燥箱变论域模糊PID复合温控设计

烘干失重法粮食水分测定过程中,干燥箱温度的精准控制是检测结果准确性的重要保障。针对干燥箱温度变化过程非线性、时滞性和温控精度高的特点,提出一种基于粒子群模型参数辨识的变论域模糊PID复合温度控制策略。基于红外辐射干燥机理及能量守恒方程建立温控系统非线性模型,并利用粒子群优化算法完成参数辨识,通过设定二级偏差阈值,将变论域模糊PID算法结合Bang-Bang控制方法构成自适应分级复合控制策略。系统仿真实验表明:相较于常规PID控制和传统模糊PID控制方法,改进后的复合控制策略在超调量、调节时间和控制进度方面明显改善,在不同工作点温度下,控制误差均小于0.4℃,且具有较好的抗干扰能力。

橡胶密封件水分测定方法制订与解析

目的制订解析《中华人民共和国药典》系列药包材标准之橡胶密封件水分测定方法。方法阐述橡胶密封件水分测定方法的制订过程,分析该标准的重点内容,对烘干法、卡氏干燥炉-库仑滴定法水分含量测定结果进行比较。结果多批胶塞样品水分含量测定结果,烘干法普遍高于卡氏干燥炉-库仑滴定法。后者专属性强,准确度高,更能反映橡胶密封件真实的水分含量。结论企业可根据其产品预期用途及日常检测需求等,从橡胶密封件水分含量测定两种方法中选择适用方法。

基于CFD的热风干燥饲料过程内流场均匀性研究

为研究热风干燥饲料过程中干燥箱内部流场分布特性,利用FLUENT软件,以干燥箱进出风方式、进气口风速以及饲料层厚度作为变量,以干燥箱湍流分布状况和风速分布状况为对象,对干燥箱内部流场均匀性进行分析,研究不同因素对饲料干燥箱内部流场分布的影响。结果表明,对侧进出风能明显降低湍流强度和湍流分布差异;当风速不变时,饲料层上表面风速均匀度与饲料层厚度成正比,下表面风速均匀度与饲料层厚度成反比;当饲料层厚度不变时,饲料层表面风速均匀度与进气口风速成反比。该研究为提高干燥箱内流场均匀性提供了理论指导。

基于Fluent的顶风式热泵干燥箱气流场分析及优化

热泵干燥箱作为当前主要的果蔬类产品的节能干燥设备,其内部流场的均匀性对干燥效率与品质至关重要。针对顶风式热泵干燥箱内部流场层间不均匀性问题,采用Fluent动网格数值仿真方法对其内部流场进行优化,提升了流场层间均匀性及干燥效率。基于顶风式干燥箱的结构特点,创新性设计了可控移动导风板机构,并针对该机构匀速运动、分段匀速运动、匀速+停滞复合运动3种方案进行了对比,结果表明,匀速+停滞复合运动方案的流场层间均匀性最佳,经优化后的层间风量分布不均匀系数低至7.02%,并通过青梅烘干实验验证了该优化方案的有效性,优化后的各层青梅含水率标准差为0.01。该系统可为顶风式热泵干燥箱流场设计和结构优化提供借鉴。

悬浮式烘箱风嘴结构的优化设计及实验验证

目的创新设计风嘴泄压孔结构,优化风嘴和基材之间由于气流撞击而形成的涡流,导致基材表面风速温度堆积不均匀的问题。方法采用Fluent软件,建立单一的风嘴仿真模型,并利用RNG k-ε湍流模型进行数值仿真模拟,分析风嘴有无泄压孔结构对基材干燥特性的影响,并在7种泄压孔设计结构中确定了相对最优方案,通过搭建实验台验证最优风嘴泄压孔结构设计的合理性。结果实验研究结果表明,通过增设相对最优风嘴泄压孔结构,基材表面涡流产生区域平均风速提高了3.32m/s,均方差降低了0.86;平均温度提高了24.76 K,均方差降低了5.96,表明设计有泄压孔结构的风嘴能明显改善由于涡流堆积造成的风速和温度较低的现象。结论设计泄压孔结构的风嘴在两狭缝之间区域的风速和温度均有明显提升,涡流区域的压力产生明显下降,改善了风嘴两狭缝之间由漩涡引起的风速、温度较低现象。

微波干燥法快速测定烟叶含水率的研究

为快速准确测定烟叶含水率,降低能耗,提高测定效率,试验采用普通家用微波炉为微波干燥仪器,探索优化试验条件,完成烟样含水率的快速测定。结果表明:在使用中高火、间歇加热4次、每次加热90 s的条件下测得的烟叶含水率与烟草行业标准方法(烘箱干燥法)所测得的烟样含水率间无显著性差异。但相对于传统的烘箱干燥法,微波干燥法可明显地降低能耗,提升工作效率。对于测定单个样本来说,微波干燥法仅需30 min即可完成单个样本水分测定过程,而烘箱干燥法需耗时100 min;另外,微波干燥法仅需消耗0.12 kWh的能量,而烘箱干燥法需耗费2.67 kWh的能量。综上所述,使用微波干燥法测定烟叶水分可获得与烘箱干燥法无显著性差异的结果,但相比于传统烘箱干燥法,微波干燥法具有耗时少、耗能低等优点。

土壤中含水率试验电热干燥箱烘干法与酒精燃烧法的对比

本研究主要对土壤含水率的电热干燥箱烘干法和酒精燃烧法两种测定方法进行了比较研究。电热干燥箱烘干法被视为国家土工试验标准中的标准方法,而酒精燃烧法则是一种常用的快速现场测定方法。通过对土样含水率的多次测定,我们发现酒精燃烧法的结果具有最高的精度,与电热干燥箱烘干法的结果有良好的线性相关性,并且结果相对稳定,符合规范要求。在快速测量土壤含水率的方法中,酒精燃烧法的准确性较高,而炒干法和明火灼烧法的误差超出了允许范围,且随着粘土质量分数的增加,误差也随之增加。主要的误差来源是加热温度超出105℃~110℃的建议范围,导致样品在高温下分解,造成额外的质量损失。酒精燃烧法可用于现场快速测量土壤含水率,而炒干法和明火灼烧法可能不适宜进行现场测试。酒精燃烧法在速度、准确性、操作简便性、节能和安全性方面均显示出优势。

酿酒稻壳水分检测方法对比研究

通过研究不同温度下卤素快速干燥法与GB/T5497粮食、油料检验水分测定法中定温定时烘干法,分别检测10个不同稻壳样品水分值,发现两种检测方法测得值相近且误差满足标准要求。从综合对比分析结果来看,卤素快速干燥法具有准确度高、稳定性强、检测速度快、操作简单和使用成本较低等优点。

变论域优化模糊PID控制器参数的温度控制

针对红外干燥箱体积小、内部结构复杂及烘干温度控制精度高等特点,提出一种基于变论域优化模糊PID控制器参数的温度控制方案。以上海良品仪器公司的XQ205型红外水分测定仪为研究对象,采用瞬态响应插值法建立红外干燥箱近似温度数学模型,为了进一步提高控制精度引入变论域策略对常规模糊PID控制器参数进行优化,通过设计伸缩因子α(x)和β(x)使得控制器模糊论域随误差变化而自适应调整,从而使得参数的选取更加灵活有效。仿真结果表明,相较于传统PID和常规模糊PID控制,变论域优化模糊PID控制策略具有无超调、动态响应快、稳态误差小及抗干扰能力强等优点,验证了该控制策略的正确性和有效性。

干燥烘箱极片表面流场特性研究

极片表面流场的均匀性是影响锂电池极片生产质量的重要因素。为了提高锂电池极片生产效率,通过流体仿真软件对烘箱风刀进行流场数值模拟,对极片表面流场进行了研究。通过提取极片表面流场速度分布情况,量化分析极片表面的流场分布的均匀性。针对极片表面风速分布不均的现象,对干燥烘箱风刀进行了优化,为接下来的进一步烘箱结构优化做基础。结果表明,经过优化后的风刀,使极片表面流场的均匀性得到了改善,防止了烘干区回风均集中在两侧导致的中间干燥不足、两边过干的情况。

铸造表干炉托盘自动清理装置的设计及应用

在铸造生产中,表干炉用于烘干砂芯涂料。工业机器人将砂芯浸涂涂料后放置在托盘上,在这过程中涂料会粘附在托盘上,多次循环使用后托盘上的涂料层会越来越厚,从而干涉到工业机器人的定位,对工业机器人的电机造成损坏。设计托盘自动清理装置的目的在于自动清理托盘表面的涂料层,提高托盘清洁程度,消除工业机器人与涂料层的干涉问题。

浅谈涂装车间烘干炉节能型风幕系统

主要讨论了在汽车涂装生产线中烘干炉常用的风幕系统原理及结构,并通过实际项目案例对烘干炉风幕系统的原理和结构进行改进和创新,实现烘干炉进、出口风幕温度可以各自调整,分别控制的效果。跟踪并记录风幕系统在运行过程中的能耗和维护成本,发现经过改进后的风幕系统能显著降低烘干设备的运行成本,实现烘干炉更加节能的目标。