空气调节讲座(六)

图6—1是啤酒发酵车间制备冷风的空气调节系统,在操作时,从外界引入的新鲜空气先进行过滤以除去大部分悬浮在空气中的灰尘和微生物,与自发酵间排出的(低温)废气进行热交换,带走部分空气的热量以减少以后的负荷。接着进入第一冷却器,它是用蛇管组装的,由制冷剂(如氨)直接冷却空气。以后与发酵间或贮酒间引出的回风进行混合后进入第二冷却器,在这里空气应被冷却到工艺所要求的温度就送入酿造车间。在这个空气调节系统中,所用的空气处理设备均为表面式空气热交换器。实际上在饮料酒生产中的空气调节系统,除了用喷淋室对空气进行湿热处理以外,还广泛使用表面热交换方式的空气调节,这类装置与喷淋式相比较用使空气调节系统简化,设备紧     

板翅式空气冷却器的应用及研究

近些年来,随着环境保护压力的增大和能源结构调整的要求越来越迫切,以风电为代表的可再生清洁能源的装机容量在电力系统的比重不断增加。当今世界风力发电技术的发展趋势表现为单机容量的逐步增大,直接导致机舱内部各系统散热量相应增大。因风电机组大多分布在恶劣的荒漠、沿海地区,空气冷却器便成为机舱内部进行各系统冷却的主要设备。空气冷却器分为板翅式和翅片管式,文章主要从板翅式空气冷却器着手,分别对空气冷却器的概述、分类、结构、选择原则、应用及存在不足等方面进行探讨,以供参考。     

浅析水电站双管式空气冷却器应用

空气冷却器是水电站中发电机系统的重要组成部分,其选型应用对设备安全可靠运行至关重大。目前广泛使用的单管式空气冷却器,由于结构设计、管材选择、制造缺陷或使用不当等方面的原因,仍存在较多渗漏情况,是发电机组的可靠稳定运行的重大隐患。由于具有渗漏监测、漏水报警、漏水收集及排水等功能,双管式空气冷却器在保障设备安全及电站可靠运行方面有着不可替代的优越性。     

冰蓄冷系统特点与应用

介绍冰蓄冷系统应用及发展呈现的特点,工作原理,分类,通过与常规制冷系统比较及方案经济评价的方法,提倡空调用冷与工艺用冷采用冰蓄冰技术,以达到均衡我国电网负荷,缓解高峰用电,提高电力建设投资效益.     

布勒公司开发冷却面粉新系统

最近,布勒公司开发了一种用冷空气冷却面粉的新系统。该系统使用方便,无需任何特殊的安全措施,在面粉中无任何残留物。该系统的工作原理是由外部大气吸入的空气经过滤清后进入空气冷却器中,空气的温度在冷却器中降低到大约6℃。空气在通过液滴分离器以后,和面粉混合进入气动输送机中,这时面粉就形成一个空气塞,在输送过程中,热的面粉与冷空气进行热交换,从而达到冷却面粉的目的。该系统最好装在需要使用输送机的地方,但也可用在任何需要采用冷却技术的工艺流程部位。在极端炎热的2 0 0 3年夏季,凡是装备了布勒公司面粉冷却系统的欧洲面粉厂,…     

来稿摘刊

来稿摘刊利用空气冷却器对酒精生产糊化醪前冷却余小军山东兰陵企业集团总公司平邑分公司（２７３５００）酒精生产糊化醪前冷却，目前主要是真空冷却工艺，在此提出的空气冷却器是利用空气作介质冷却糊化醪，节水、节电，经济效益可观。该空气冷却器为一圆柱形设备，在圆...     

再谈空气冷却器风机的安装位置

目前我国肉类加工业正在向深度发展,分割肉生产增长速度加快,这样空气冷却器不仅在高温冷库、肉类结冻间采用,而且在白条肉的预冷、分割肉车间的空调,成品肉的预冷和包装间等也都采用空气冷却器。如我们正在设计的内江分割肉车间,日产分割肉35吨,空气冷却器总共达36台(包括分割肉结冻在内)。对空气冷却器的结构形式,我国习惯上多将风机安装在冷却排管的后面,     

冰蓄冷技术在粮食储存中的应用及发展研究

阐述在粮食低温储存中应用冰蓄冷技术的意义,介绍冰蓄冷空调系统的构成与工作原理,简述冰蓄冷技术的“移峰填谷”功能,对冰蓄冷技术的发展前景进行简要分析.     

浩邦生物技术 星邦生化设备

正发酵尾气处理、无菌空气预处理专家生物工程节能减排、增效环保专用设备设计制造商●高效旋击分离器——分离效率98%-99.99%。在发酵尾气处理系统中应用,杜绝尾气逃料,发酵放罐体积增加5%-10%,消泡剂用量减少1/3左右。活菌体排放大幅减少,稳产环保。●空气冷却器、卧式气液分离器、空气(循环)加热器组成节能发酵无菌空气预处理系统——使空气系统阻力大幅下降,高温空气热量回收利用。系统     

冰蓄冷在纺织厂空调系统中运用前景分析

介绍了蓄冷空调技术的特点和现状,将冰蓄冷空调与普通纺织厂压缩式空调系统做了详细的技术和经济性比较,并针对纺织厂空调的特殊工艺要求提出了相应的改进,将冰蓄冷技术运用到纺织厂空调中,进而达到节能降耗的目的。     

Effects of Simulated Retail Display and Overnight Storage Treatments on Quality Maintenance in Fresh Broccoli

The quality of fresh broccoli during simulated retail display was evaluated using contact (ice) and air cooling separately and in combination. Chlorophyll and ascorbic acid were best maintained with air cooling, while weight was best maintained with ice cooling alone. In air-cooled display units, ice placed both on top of and beneath broccoli heads resulted in more rapid loss of chlorophyll and ascorbic acid than did bottom-icing alone. Bottom-iced broccoli in air-cooled units kept best overnight if left in place and covered with wet burlap. Removal to a 4°C walk-in cooler each night resulted in good color retention and marketability but weight loss after 4 days was significantly higher.     

冷冻浓缩过程中制冷面的冰淤塞的检测与表征(Ⅰ)

冷冻浓缩是一种可望替代或部分替代传统蒸发浓缩或反渗透浓缩、用于对食品溶液或生物溶液进行浓缩或预浓缩的特殊方法.然而在冷冻浓缩的实践中发现,冰层对制冷面的包覆,即冰淤塞,即使换热面是在很小的过冷下度下(如过冷温度只有0.2℃)仍然是不可避免的.冰淤塞使制冷面的传热系数显著下降.本研究还发现冰晶在制冷面上直接释放结晶潜热使...     

Ice Cream: Foam Formation and Stabilization—A Review

Ice cream has been studied from ingredients to process conditions, ice crystal formation to ice crystal growth, and ingredient selection to eating quality. One of the key aspects of ice cream is air cells, as formation and acceptance of ice cream rely on foam production and stabilization. Air cells in ice cream provide a unique structure that governs many of this product's keeping and eating qualities. The air cells are dependent upon ice cream mix composition (fat, protein, and surface active ingredients) as well as processing conditions (freezer shear force, hardening time, and storage temperatures). Optical, low-temperature scanning electron microscopy and transmission electron microscopy are applied to observe the morphology and size of air cells in ice cream. Air cells are crucial in forming the product and for eating quality and enjoyment.     

渔船用冷冻冷藏系统的研究进展

在渔船渔业作业过程中,渔获物的冷冻冷藏方式直接影响着渔获物本身的营养价值与经济价值。文章在分析不同制冷系统及冷藏方式的基础上,综述渔船上常用的冷冻冷藏系统的研究进展,以期为渔船用渔获物冷冻冷藏系统改进与优化设计研究提供依据。目前,渔船常用的渔获物冷藏保鲜方式分4种:冰藏保鲜、冷海水保鲜、微冻保鲜及冻结保鲜。其中,前3种冷藏保鲜方式通常采用单级压缩制冷系统,冻结保鲜则通常采用单机双级活塞式压缩制冷系统。渔船低温冷藏舱中常使用的蒸发器形式主要有冷风机和直接蒸发盘管两种。中国的渔船用制冷系统多使用不环保的R22作为制冷剂,寻找新型环保、安全、高效的替代制冷剂亦是当下研究的热点。     

Vitamin A in irradiated foodstuffs (author's transl)]

Vitamin A losses induced by 10 MeV electrons in cream cheese, calf liver sausage, pig liver, whole egg powder and margarine continued to increase during storage for 4--8 weeks in presence of air. Thus vitamin A loss in sausage irradiated with 5 Mrad was 22% on the day after irradiation, 61% after 4 weeks. Irradiation and storage at 0 degrees C instead of at ambient temperature reduced these losses considerably. Exclusion of air (vacuum, nitrogen) or irradiation on dry ice (approx. -80 degrees C) were even more effective in preventing destruction of vitamin A. After 4 weeks of storage, cream cheese irradiated at 5 Mrad had lost 60% when irradiated and stored in air at ambient temperature, 20% in nitrogen atmosphere, 5% in vacuum package, and 5% when irradiated on dry ice and stored at ambient temperature.     

DRY ICE IN VARIOUS SHIPPING BOXES FOR CHILLED POULTRY: EFFECT ON MICROBIOLOGICAL AND ORGANOLEPTIC QUALITY

SUMMARY– Comparisons were made of dry ice and weter ice in shipping boxes for chilled chickens. Three types of boxes were tested: wax-resin-coated corrugated fiberboard, expanded polystyrene foam, and wirebound wood-veneer. Microbial counts, CO₂ concentration, and off-odor development were determined. Microbial counts on poultry stored at 0.5°C for up to 9 days were not significantly different as a function of box type or coolant. Counts on poultry stored at 4.4°C were significantly greater at 9 days on poultry stored in fiberboard boxes with dry ice than on poultry with water ice in fiberboard boxes or polystyrene boxes with dry ice; at 3 and 6 days there were no significant differences. At 5.2°C, counts were significantly smaller in polystyrene boxes with dry ice than in either wirebound boxes with water ice or fiberboard boxes with dry ice. An off-odor not characteristic of spoilage odor could develop in CO₂ atmosphere storage earlier than spoilage odor in an air atmosphere if storage temperature was low (0.5°C). At higher temperature (5.2°C), spoilage odor in air occurred earlier than Co₂-related off-odor in Co₂ atmosphere.     

基于单冷源空调系统的温湿度独立控制方法

为解决卷烟企业一次回风空调机组在夏季温湿联合调节模式下运行时间长、运行能耗及成本高等问题,以储丝房为例,基于单冷源建立了一种空调系统温湿度独立控制方法,并对空调机组的热湿控制功能段及控制方式进行了改进:①加装一次表冷器,用于机组除湿控制,原表冷器作为二次表冷器,用于机组降温控制。一、二次表冷器冷媒水串接在一起,利用一次表冷器在热交换过程中冷媒水的升温,使二次表冷器的进水温度升高3~5℃,实现单冷源的温湿度独立控制;②新风段增加了新风独立除湿机组,在夏季运行工况时,将原有的温湿度联合控制逻辑调整为温湿度独立控制。结果表明,采用温湿度独立控制方法,有效解决了夏季温湿联合调节模式下冷热抵消、能源浪费等问题,空调机组除湿能耗下降25.5%,提高了空调机组的运行效率。      

A study of the ice crystals in vacuum-packed salmon fillets (Salmon salar) during superchilling process and following storage

The aim of this work was to study the microstructure of vacuum-packed salmon fillets superchilled in an impingement freezer at −30 °C (air temperature) and 227 W/m² K (surface heat transfer coefficient, SHTC) for 2.1 min prior to storage at a superchilling storage temperature of −1.7 ± 0.3 °C for 28 days. The microstructure of vacuum-packed salmon fillets were analysed at the surface, mid-centre and centre layers. Significant differences were observed between the ice crystals formed at the surface, mid-centre and centre layers. The size of ice crystals at the centre of the superchilled fillets was 3 times larger than those at the surface layer. Significant differences were observed between the size of ice crystals formed during the superchilling process and following storage. The results further indicated that, after temperature equalisation (1 day of storage) the growth of the intracellular ice crystal was not significant at (P < 0.05) at any storage time.     

农产品的湿空气保鲜新技术

与传统的冷库相比,采用冰蓄冷和湿空气保鲜的新型冷库效果更好,在欧洲和美国已被广泛应用于果蔬、花卉的保鲜.本文阐述其工作原理、优点和应用实例.