略论制盐热利用率的提高

1制盐真空系统进出热量概述真空制盐中，输人系统的热量是一定的。由于蒸发过程中冷凝水、二次蒸汽要带走一部分热量，输入系统的热量不可能全部被有效利用。减少热量损失，提高系统的热利用率，对于节能降耗、挖潜增效具有很重要的意义。制盐系统的热量进出如图豆。1．1热量进入情况输入的热量生蒸汽温度130℃，压力0．22346MPa，烙值2724kJ/kg，总流量43．3t／h，其中进加热室38t／h，进蒸喷1．st／h，进散热器3．st／h，则输人的热量为：43．3X103x2724—117．困1制盐系统热且走向示意图95X106klch输出的热量1效冷凝水温度为100℃，流…     

葡萄酒酿造中的控温发酵技术

葡萄汁发酵是在酵母菌的作用下，将汁中的糖转化为酒精的过程。随着酒精的生成，产生一定量的CO2并放出大量的热，该放热反应可使发酵醪的温度上升，会直接影响到酒的质量。因此，控温发酵是高品质葡萄酒酿造中的一项主要技术措施。1．葡萄对发酵时的产热量计算据试验，当糖、酒精和CO2在标准状态下，可产生23．5千卡的热，即1千克分子糖（180克）变成酒精时，放出的热量为23．5千卡。因此，可根据下式计算出发酵汁的温度上升情况。上两式中：Q一葡萄汁发酵时放出的热量（千卡）s──葡萄汁的含糖量（％）V──萄汁的总容量比）温度升高…     

基于多温制冷的冷藏车标准分析

冷藏车是专用汽车领域的一种重要车型,在冷链运输中起到了核心作用。随着市场需求的日益提升,支持多温制冷的冷藏车发展迅速,实际应用广泛,而相关国内标准目前处于滞后状态,缺乏多温制冷冷藏车的技术参数要求。文章从冷藏车市场现状、国内外标准内容、多温冷藏车制冷量的计算方法及要求对多温制冷冷藏车标准进行分析,提出了相关标准制修订的方向。     

糖尿病患者的饮食疗法(二)

专家指导 （四）怎样使用“食物成分表计算法”制定食谱？ 食物成分表计算法。是其他计算法的基础，适用于住院病人。具体方法： （１）确定总热量：这是计算饮食的第一步，每日所需总热量Ｘ＝热卡／每日公斤体重×标准体重。 １）病人每日每公斤体重所需热卡，主要受病人从事的劳动强度影响，不同劳动强度所需热量亦不同：休息约２５－３０千卡，轻体力劳动或脑力劳动为主者３０－３５千卡，中体力劳动者为３５－４０千卡，重体力劳动者４０千卡以上． ２）标准体重：即理想体重。取决于年龄、性别、身高等。确定标准体重方法有两种：计算…     

利用机器散热采暖的实践

我厂拥有3万枚纱锭，配有4t锅炉一台，每天耗煤10t左右，全年采暖用煤量约1000t。1996年我们围绕学“邯钢”，节能降耗，降低成本，摸索出一条充分利用车间机器散发的热量，冬季不烧锅炉采暖的路子．每年节约用煤约1000t，经济效果显著。l理论依据1．1设定条件荷泽地区规定，棉纺织厂采暖开炉时间为当年11～12月份到下年的1～2月份。根据气象资料和纺纱工艺要求，我n］做以下设定：室外温度为一10“C，各车间要求达到的温度见表1。表1各车间设计温度单位：C1．2各车间热负荷计算1．2．l各车间房屋热损失根据厂房结构、传热面积、各结构传热…     

糖化过程热负荷评估模型的建立与应用

引言：在工程学上，热负荷（HeatDuty）是指为了维持室内一定的温度和湿度，在某一时刻供给房间的热量。啤酒的热负荷是指啤酒酿造与储运过程中直接或间接所承受的热量，它主要由受体温度的高低与在该温度下停留时间的长短所决定。在原辅料质量与其使用比例一定的情况下，     

甘蔗宿根矮化病热处理器的设计与研制

热水处理蔗种防治甘蔗宿根矮化病是一项有效措施。本文根据热自理消毒的基本要求，通过对影响水温度的主要因素的分析，箱体加热量和散热量的计算，介绍了热处理器的工作原理、设计方法及加温、保温的控制系统。     

减少热负荷在啤酒生产中的应用研究

阐述了热负荷的研究意义和发展。通过糊化免煮沸工艺、分段低蒸汽压力煮沸工艺对减少热负荷的影响研究,量化了过程控制的指标与方法,92．0℃糊化,麦汁碘值平均降低44．7％;在分段低蒸汽压力煮沸研究中,分析了低压煮沸强度（X）与可凝固性N（Y）、泡沫蛋白（Z）、老化前驱物质的关系,Y=-3．9102X＋35．479,煮沸强度下降0．6％,麦汁老化前驱物质约下降13．3％,Z=-0．0444X＋0．568,建立了对应的数学模型,并应用于实践中;研究中,导入热力学能量计算方式,为减少热负荷工艺提供支持。     

太阳能热水器关键词条

得热量 是指太阳能热水器从光照中获得的实际可用的总热量，是衡量太阳能热水器的综合性指标，是影响热水器水温高低的关键。得热量的大小主要取决于真空管直接得热量、反光得热量及热损。     

户式中央空调节能新技术 谷轮数码涡旋技术

空调利用蒸发器的室内冷盘管为居室制冷．用冷凝器的户外热盘管将收集的热量散发到室外。蒸发器与冷凝器盘管通常由铜管制成，管上带有铝散热片。压缩机驱使制冷剂(一种传热液体)在蒸发器与冷凝器之间循环。液体制冷剂在室内的蒸发器盘管中蒸发，将室内空气中的热量吸走．使居室得到冷却。之后．热的制冷剂气体被泵送到户外的冷凝器中．将所带的热量释放给流经冷凝器金属管片的空气，在这个过程中制冷剂由气态变回到液态。     

Heat transfer modelling in a ventilated cavity loaded with food product: Application to a refrigerated vehicle

A simplified heat transfer model of a refrigerated vehicle was developed in which two loads (front and rear) are considered. The front load located near the supply air duct is subjected to higher air velocity and lower air temperatures compared with the rear load, leading to product temperature heterogeneity. The model takes into account heat transfer by convection between the internal air and the load, between the external air and the walls of vehicle and by conduction in these walls. Air infiltration during door openings is also considered. Model validation was carried out by comparing the calculated product temperatures with those obtained from transport of fruits and frozen foods in a semi-trailer. Good agreement between the experimental and calculated results was obtained.     

THERMAL PROCESS SIMULATION of CANNED FOODS UNDER MECHANICAL AGITATION1

This paper describes how the distributed parameter conduction-heating numerical model was modified and tested to accurately predict the can center temperature for canned foods which exhibit combined heat transfer of pure conduction with added forced convection caused by mechanical agitation. This innovation will open the door to more widespread use of such mathematical models as part of the control system logic for making accurate adjustments to process conditions in response to unexpected retort temperature deviations on line during thermal processing of canned foods in agitating retorts.     

Process for calcium retention during skim milk ultrafiltration

Lactose is separated from milk or other fluid dairy products for a variety of reasons. Ultrafiltration is a known process of removing lactose from these products. However, during ultrafiltration, valuable minerals, such as calcium in soluble form, are also lost into permeate. In this study, a process was developed in which first the lactose reduction in skim milk was achieved by ultrafiltration (4x volumetric concentration) using a 10-kDa membrane. Then, the calcium present in permeate was precipitated using one of three methods: 1) heat treatment, 2) pH adjustment, or 3) a combination of pH adjustment and heat treatment to permeate, then recovered by refiltering permeate. The process was first developed at laboratory scale, and then its applicability was tested at the pilot scale. Skim milk, retentates, permeates, and the treated permeates were analyzed for total solids, ash, protein, or total nitrogen, calcium, and lactose content. About 76% of the total lactose and about 16% of the calcium present in skim milk permeated through the membrane during ultrafiltration. The three treatments applied produced white precipitates and turned the clear permeates turbid. On refiltering the treated permeates approximately 42, approximately 50, and approximately 70% of the total calcium present could be recovered from 1) heat-treated, 2) pH-adjusted, and 3) pH-adjusted and heat-treated permeates, respectively. There was no marked change in the lactose content due to any of the three treatments and subsequent refiltering of the treated permeates.     

Ultrasonication as a novel processing alternative to pasteurization for camel milk: Effects on microbial load,protein profile,and bioactive properties

Ultrasonic technology presents a promising novel tool in the food industry for the processing of milk and dairy products. In this study, we investigated the effects of ultrasonication (US) as an alternative to thermal pasteurization for stabilization of the bioactive properties of camel milk. Camel and bovine milk samples were subjected to US at 6 different power levels (US1–US6), and 1 set of each type of milk was concurrently subjected to flash heat pasteurization (FHP) for comparative analysis (100 mL; n = 4). The microbiological and bioactive parameters of the samples were analyzed during 7 d of storage at 4°C. In both milk types subjected to US ≥ 140 W (US3), the bacterial load was reduced by almost 4 log cycles and complete reduction of microbial load was achieved with US = 170 W and US = 210 W (US5 and US6 treatments, respectively). No significant changes in protein patterns were observed with either FHP or US treatment. In addition, bioactive properties (cholesteryl esterase and pancreatic lipase inhibition) were either enhanced or retained at US3 or higher. 2,2′-Azino-bis-3-ethylbenzthiazoline-6-sulfonic acid and ferric reducing antioxidant power activities in camel milk were decreased after FHP treatment but increased or retained upon US, particularly at US3 and US4 (160 W). Overall, under our experimental conditions, US4 was effective in completely reducing the microbial count, while concomitantly retaining different bioactive properties of both camel and bovine milk. These outcomes highlight the potential of US at 160 W as an efficient nonthermal alternative processing method for milk.     

HEAT TRANSFER TO WATER AND SOME HIGHLY VISCOUS FOOD SYSTEMS IN A WATER-COOLED SCRAPED SURFACE HEAT EXCHANGER

Heat transfer in a water-cooled scraped surface heat exchanger has been investigated. The overall heat transfer coefficient in the heat exchanger is composed of three elements: heat transfer coefficient in the coolant jacket, resistance to heat flow in the separation wall and heat transfer coefficient inside the scraped cylinder. A method for assessing the heat transfer coefficient at the coolant side was developed. In contrast with studies published elsewhere, heat transfer was investigated with food systems which are non-newtonian and possess a complicated and unknown flowing behavior at higher shear rates. For water and three starch-based food products (starch content 12–18%) the heat transfer coefficients inside the scraped cylinder were measured for shaft speeds ranging from 1.67 to 10 revolutions/s. The experimental results were compared with heat transfer coefficients calculated with a model based on the penetration theory. For the starch-based products, in general, no consistent interactions between mass flow rates and internal heat transfer coefficients were observed. In the shaft speed range studied heat transfer coefficients at scraped surface varied from 3200 to 7800 W/m² K for water, from 500 to 3150 W/m² K for velouté sauce, from 670 to 1330 W/m² K for roux and from 780 to 1900 W/m² K for ragout.     

皮革面料抗粘连性的测试方法研究

对采用汗渍试验仪给试样均匀施加负重下的干热试验、湿热试验和磨损涂层后的抗湿热粘连试验方法进行了考察,试验结果表明三种测定方法能测定出皮革面料抗粘连性的差异,并且一般情况下干热试验方法测定所得皮革面料抗粘连等级较另外两种方法的高。     

Enhanced bioaccessibility of β‐carotene from yellow‐orange vegetables and green leafy vegetables by domestic heat processing

Effect of heat treatment involved in domestic cooking on the bioaccessibility of β‐carotene from yellow‐orange as well as green leafy vegetables was evaluated. Heat treatment of these vegetables by pressure‐cooking, stir‐frying and open‐pan boiling had a beneficial influence on the bioaccessibility of β‐carotene. The extent of increase in the per cent bioaccessibility of β‐carotene as a result of pressure‐cooking was 21–84%. Stir‐frying in presence of a small quantity of oil brought about an enormous increase in the bioaccessibility of β‐carotene from these vegetables, the extent of increase being 67–191%. Open‐pan boiling of vegetables increased the bioaccessibility of β‐carotene in the range 23–36%. Thus, among the three domestic heat processing methods, stir‐frying results in maximum bioaccessibility of this provitamin. The use of suitably heat‐processed vegetable sources of β‐carotene could form a dietary strategy to derive this micronutrient maximally by the population dependent on plant foods.     

Study of the antifungal potential of novel cellulose/copper composites as absorbent materials for fruit juices

Cellulose/copper composites with antifungal properties have been synthesized by physical/chemical methods. Physical treatments by heat or by a combination of heat and UV radiation provided composites with metallic copper and excellent interfacial adhesion; in contrast, chemical reduction with borohydride generated small although partially aggregated copper oxide nanoparticles. Copper micro/nano-particles and copper ions (Cu(2+)) were released from the cellulose matrix at an adequate rate to achieve a strong antimicrobial activity against Saccharomyces cerevisiae in in vitro experiments. Moreover, the copper oxide composites showed an excellent antifungal activity in pineapple and melon juice, reducing about 4 log cycles the loads of spoilage-related yeasts and moulds. The metallic copper composites reduced in 4 log cycles the load of yeasts and moulds in pineapple juice, although their antifungal activity was weaker in contact with melon juice. Copper loaded absorbent materials could be selectively implemented during the shelf-life of minimally processed fruits to reduce the number of spoilage-related microorganisms in the drip.     

热加工方式对火麻仁风味与品质的影响

采用常压蒸制、炒制、热风烘烤以及微波4种热加工方式处理云南大姚火麻仁.以火麻仁香味为指标,探究4种热加工方式在最佳香味处理条件下对其挥发性风味物质、色泽、营养成分及贮藏稳定性的影响.结果表明:4种热加工方式最优处理条件分别为100℃常压蒸制8 min、150℃炒制15 min、130℃热风烘烤40 min以及600 W...     

Monitoring Food Product Temperatures during Convective Heating: Implications for Research Procedures

Turkey rolls were heat processed (105°, 135°, and 165°C) in an electric convection oven with loads of 2, 4, and 6 rolls. Data were analyzed when 50, 66, 83, and 100% of thermocouples (three/roll) reached 77°C. Processing time for 2 rolls, (min/load) and (min/kg), was significantly greater (p<0.05) only at 105°C, when 100% versus 50% of thermocouples were monitored. Energy consumed was not different for 2 or 4 rolls. Processing time differed (min/load) but not min/kg, when 4 and 6 rolls were heat processed at 135°C, depending on the percentage monitored. The percentage monitored significantly changed WH/load but not WH/kg, only when a load of 6 rolls was processed. Determining temperatures on the basis of readings from 50 to 100% of thermocouples did not affect energy data.