乳浓缩中析式蒸发器结垢的形成及其预防措施

介绍了板式蒸发器的主要结构及工作原理,通过对板式蒸发设备表面成垢机理及结垢特点的分析,明确了供料不足、蒸汽太大、进料温度过低是造成结垢的主要原因.提出了控制进料流量和速度,改变加热介质以及加强乳品蒸发过程的浓度控制等措施,以便预防板面结垢.     

岳阳纸业集团公司板式降膜蒸发器的运行及其性能优势

本文通过对板式降膜蒸发器运行及其性能优势的介绍，阐明了板式降膜蒸发器具有热效率高，结垢速率低，运行周期长，操作灵活简便等特点，是一种可以值得推广使用的蒸发设备。     

酒糟离心液在异形竖板上降膜蒸发传热研究

在点窝状波纹表面的竖板式传热元件上进行了酒糟离心液降膜蒸发传热实验研究，分析了进料流量、蒸发温度、传热温差和操作浓度等参数对传热性能的影响，并就设计与操作提出了看法。     

板式降膜蒸发器应用于荻苇浆黑液蒸发的特点

本文主要介绍了板式降膜蒸发器站应用于荻苇浆黑液蒸发的主要特点及生产运行过程中主要发现的问题及改进措施,与管式蒸发站相比,充分肯定了板式降膜蒸发站的性能优势。     

试谈硫酸钠型卤水真空制盐装置结垢的防治

本文分析了硫酸钠型垢层的形成基理和原因，简述了在生产过程中为了防止制盐设备结垢所采取的几项措施。提出了采用轴向进料蒸发结晶技术防垢的观点。     

对我矿15万吨／年制盐装置生产的看法

湖南湘衡盐矿１５万吨／年制盐装置，系外热式轴向进料装置，于１９９４年１０月投产，投产仅几天就发现加热管加重堵塞，蒸发室盐块多，特别是Ⅰ效蒸发室结垢甚为严重。本文作者根据生产实践，分析了造成堵管或结垢的原因，提出了进行技术改造的途径。经过技术改造后该装置运行平稳，盐产量达到５５０～７００吨／日的好成绩。     

我国麦草浆碱回收的进展与主要经验和建议（下）

4.1996年以来新上麦草浆碱回收的蒸发站设计,大都采用了“两板三管”的型式,运行实践证明是有效的,蒸发强度高、蒸发效率高、不易结垢,收到了节能降耗的好效果。目前,国内板式蒸发器的大型制造厂家已有3家,即江苏华机集团张家港沙工化机厂、兰州节能环保工程有限责任公司、天津轻工业机械厂。这3家工厂生产的板式蒸发器都已达到国际先进水平,并且在麦草浆碱回收系统都已有成功运行的实例,可以说板式蒸发器的国产化是成熟的、可靠的,完全可与进口同类设备相媲美。华机集团生产板式蒸发器的历史较长,管理严格,质量过硬,在国内覆盖面较广。兰州节能环保公司开始走过弯路,近几年痛下决心,卧薪尝胆,引进先进焊接技术,并在板片鼓泡成型上独具特色,产品定型性好、不变形,在麦草浆黑液蒸发时长期     

化学法控制草浆黑液蒸发器的结垢

草浆黑液蒸发系统结垢问题严重,本文分析出结垢原因,对采用草浆黑液结垢控制剂后的使用效果进行叙述并展开讨论。     

板式蒸发器设计应注意的几个问题

板式蒸发器的最大优点是体积较小,占用空间小;与管式降膜式蒸发器一样在负压下蒸发,属于低温蒸发,其主要形式有升膜式、升降膜式及降膜式三种,降膜式在国内还不多见。对升降膜板式蒸发器存在的问题及设计时应注意的事项进行了阐述。     

蒸发器液室结垢的原因浅析

１设备及工艺流程介绍碱回收系统中蒸发器的作用就是把制浆系统送来的稀黑液浓缩到一定的浓度供碱炉燃烧。蒸发过程实际上就是黑液脱除水分的过程。目前国内采用的较为普遍的蒸发器主要有两大类，即，管式升膜蒸发器和强循环降膜蒸发器。我公司＃１蒸发站采用的是１９６７年从芬兰Rosen－blad公司引进的五效不等面积管式升膜蒸发器。而＃２蒸发站是１９９０年由天津轻机厂提供的，为五效全板式降膜蒸发器，该蒸发站与＃１蒸发站相比具有不易结垢和环境污染轻等优点。但在１９９２年底蒸发站投入运行之后，由于设计、工艺及设备上存在的一些…     

Effect of whey protein concentration on the fouling and cleaning of a heat transfer surface

In the studies of fouling and cleaning of heat exchange surfaces in dairy plants, whey protein deposits and heat induced whey protein gels (HIWPG) are considered as suitable model material to simulate the proteinaceous based type “A” milk fouling. Protein concentration of the fouling solution may significantly influence the formation of milk deposits on heat exchange surfaces, hence affecting the cleaning efficiency. In this study, a laboratory produced heat induced whey protein gels (HIWPG) and a pilot plant heat exchanger fouling/cleaning were used to investigate the effect of protein concentration on formation and cleaning of dairy fouling. Here, HIWPGs made from different protein concentrations were formed in capsules and then dissolved in aqueous sodium hydroxide (0.5 wt%). The dissolution rate calculation based on the UV spectrophotometer analysis. In the pilot-scale plant study, whey protein fouling deposits were formed by recirculating whey protein solutions with different concentrations through the heat exchange section in different runs, respectively. The deposit layers were then removed by recirculating aqueous sodium hydroxide (0.5 wt%) and the cleaning efficiency was monitored in the form of the recovery of heat transfer coefficient while both fluid electric conductivity and turbidity were monitored as indications of cleaning completion. It was found that increasing the protein concentration of the HIWPG significantly increased the gel hardness and the dissolution time. In addition, increasing the protein concentration significantly increased both, the amount of the fouling on the pilot-scale plant and the time required to clean the fouling deposit.     

Formation of dairy fouling deposits on food contact surfaces

This study aimed to compare microbiological, biochemical and physical methods to quantify dairy fouling deposits. The influence of factors affecting dairy fouling formation is investigated by selected methods with respect to material type (polytetrafluoroethylene and stainless steel) and temperature (4 and 20 °C) for a defined time. The factors were investigated using nonmicrobiologically caused and microbiologically caused dairy deposits formed by UHT and pasteurised milk inoculated with Pseudomonas fragi. Both deposit types exhibited different adhesion behaviours. The highest positive correlation coefficient was found between biochemical and microbiological methods (0.932) obtained at both incubation temperatures after 24 and 48 h.     

乳制品质量快速检测原理与技术研究进展

乳制品是鲜奶以及所有以奶为主要原料加工制成的产品的总称,乳制品的安全问题是全球关注的热点。为了对乳制品质量进行监控,目前已有的检测标准和方法需要在实验室进行,检测环境条件要求较高,周期较长。研究并开发灵敏、准确、便捷的检测方法十分必要。近年来,一系列新的乳制品质量快速检测技术已经被广泛应用,本文主要介绍了电子学、光谱学和生物学检测技术的原理及其在乳制品质量检测应用中的优缺点,同时展望了乳制品质量检测技术的发展方向,旨在为乳制品质量检测技术的进一步发展提供资料参考和思路。     

A critical review on surface modifications mitigating dairy fouling

Thermal treatments performed in food processing industries generate fouling. This fouling deposit impairs heat transfer mechanism by creating a thermal resistance, thus leading to regular shutdown of the processes. Therefore, periodic and harsh cleaning-in-place (CIP) procedures are implemented. This CIP involves the use of chemicals and high amounts of water, thus increasing environmental burden. It has been estimated that 80% of production costs are owed to dairy fouling deposit. Since the 1970s, different types of surface modifications have been performed either to prevent fouling deposition (anti-fouling) or to facilitate removal (fouling-release). This review points out the impacts of surface modification on type A dairy fouling and on cleaning behaviors under batch and continuous flow conditions. Both types of anti-fouling and fouling-release coatings are reported as well as the different techniques used to modify stainless steel surface. Finally, methods for testing and characterising the effectiveness of coatings in mitigating dairy fouling are discussed.     

COMPARISON of TWO OPERATING METHODS of A PLATE HEAT EXCHANGER UNDER CONSTANT HEAT FLUX CONDITION and THEIR EFFECT ON the TEMPERATURE PROFILE DURING MILK FOULING

Two methods of operating a plate heat exchanger under constant heat flux were studied: Method A) control by increasing the flow rate of the heating medium; and Method B) control by increasing the inlet temperature of the heating medium. the cross-sectional temperature variation in the plate used in this study was smaller than that of an intermating-type plate. A change in the axial temperature profile was discovered as a result of the uneven formation of milk deposit along the channel. the temperature changes of both the milk and the solid-milk interface (stainless steel-milk or deposit-milk) during fouling were larger when the effects of fouling were overcome by increased flow rate of heating medium than when the effects of fouling were overcome by increased temperature of the heating medium. A quadratic empirical model underpredicted the temperatures in the lightly fouled region and overpredicted the temperatures in the heavily fouled region.     

The application of process analytical technologies (PAT) to the dairy industry for real time product characterization - process viscometry

The ideal PAT tool is an inline instrument that can monitor and measure process parameters simultaneously in real time while operating in a highly automated environment. Instruments must be of sanitary design, operate robustly within the full process cycle (production and cleaning). Inline determination of the rheological properties of moving fluids (i.e. dairy concentrates) is one of the process parameters where PAT tools can be add real value in terms of optimising process control. Measurement of process viscosity is crucial in the monitoring and control of a variety of concentration processes in the dairy industry. Continuous monitoring of the rheological behaviour of the fluid can allow for optimisation of the process e.g. pumping (avoid pump blockage and failure), evaporation (limit fouling and maximise water removal) and spray drying (avoidance of nozzle fouling). This review concentrates on the state of the art developments being made in the area of process viscometry.     

Short communication: Evaluation of a sol-gel–based stainless steel surface modification to reduce fouling and biofilm formation during pasteurization of milk

Milk fouling and biofilms are common problems in the dairy industry across many types of processing equipment. One way to reduce milk fouling and biofilms is to modify the characteristics of milk contact surfaces. This study examines the viability of using Thermolon (Porcelain Industries Inc., Dickson, TN), a sol-gel-based surface modification of stainless steel, during thermal processing of milk. We used stainless steel 316L (control) and sol-gel-modified coupons in this study to evaluate fouling behavior and bacterial adhesion. The surface roughness as measured by an optical profiler indicated that the control coupons had a slightly smoother finish. Contact angle measurements showed that the modified surface led to a higher water contact angle, suggesting a more hydrophobic surface. The modified surface also had a lower surface energy (32.4 ± 1.4 mN/m) than the control surface (41.36 ± 2.7 mN/m). We evaluated the susceptibility of control and modified stainless steel coupons to fouling in a benchtop plate heat exchanger. We observed a significant reduction in the amount of fouled layer on modified surfaces. We found an average fouling weight of 19.21 mg/cm² and 0.37 mg/cm² on the control and modified stainless steel coupons, respectively. We also examined the adhesion of Bacillus and biofilm formation, and observed that the modified stainless steel surface offered greater resistance to biofilm formation. Overall, the Thermolon-modified surface showed potential in the thermal processing of milk, offering significantly lower fouling and bacterial attachment than the control surface.     

酒糟离心液降膜蒸发过程中结垢的实验研究

在宽0．5m、高1．0m的点窝状异形竖板传热元件上进行了酒精离心液的结垢的实验研究，分析了酒糟离心液絮垢的形成过程，讨论了影响结垢的主要因素，提出了减缓成垢的措施。     

Analysis by Raman spectroscopy of the conformational structure of whey proteins constituting fouling deposits during the processing in a heat exchanger

Whey protein fouling deposits generated on the hot wall downstream a plate heat exchanger were analyzed by micro Raman spectroscopy (MRS) carried out in the 800-1800 cm⁻¹ range. Deposits were formed using a model beta-lactoglobulin (BLG) fouling solution which was made using a whey protein isolate powder (89 wt.% in BLG) and a known amount of calcium. Thermal denaturation of the fouling solution was also analyzed by MRS as well as isolated BLG aggregates obtained by microfiltration of heated solutions. Specific Raman signatures of aggregates were identified, which were not detected in the Raman spectra of denatured (i.e. unfolded BLG molecule) solutions. MRS analyses at different depths of the deposit reveal a loss of α-helix structures, as observed in denatured BLG solutions, without the detection of aggregate signatures. For the range of calcium content investigated (from 97 to 160 mg l⁻¹), no effect of calcium ions on the molecular conformation of BLG within the deposit was shown. Of great significance, results suggest that, for our set of operating conditions used, the mass distribution of the fouling deposit in a plate heat exchanger is primarily controlled by the distribution of the unfolded protein generated by the denaturation process.     

基于PI荧光图像计数的乳制品荧光性质分析

为分析添加PI染料时乳制品中不同的荧光成分如酪蛋白、黄油、维生素B1、维生素B2、维生素C等对荧光图像观察的影响,探究了不同乳制品及其成分在PI染色观察条件下的荧光性质,并以酿酒酵母为目标菌,研究了10种乳制品中酿酒酵母PI荧光图像计数结果。结果表明,酪蛋白、黄油、维生素B1、维生素B2、维生素C等成分及10种乳制品在发射光615 nm均可产生荧光,但不影响PI染色的酿酒酵母荧光计数的观察结果。使用荧光显微镜对添加105~107 CFU/mL酿酒酵母菌液的10种乳制品进行PI染色计数,并将荧光图像计数结果与平板计数结果进行比较。其中经荧光图像计数后得到的菌液浓度对数值分别在5.69~5.93、6.18~6.28、7.13~7.21之间,对应平板计数结果的对数值分别5.49~5.63、6.02~6.06、7.02~7.06之间,二者结果一致。使用 PI 进行荧光图像计数时,乳制品荧光虽然存在但不会对酿酒酵母荧光图像观察与计数造成影响。