并流多效蒸发淡碱浓缩的矩阵算法

研究了求解有额外蒸汽引出的并流多效蒸发淡碱浓缩工艺数学模型的一种新算法———矩阵法 ,利用可视化语言VisualBasic 6 0编制了淡碱多效蒸发浓缩的计算程序。新算法优于目前已有的各种多效蒸发工艺计算方法 ,具有对初值要求不高、收敛稳定性好、收敛速度快等优点。算例表明 ,引出额外蒸汽预热淡碱节能效果显著。     

间隔式热泵流程在多效蒸发中的应用研究

文章针对热泵多效蒸发流程进行优化,提出了更加具有经济性的间隔式多效蒸发热泵流程.根据多级蒸汽喷射式热泵设计理论,为一套四效蒸发工艺设计了两级的喷射热泵.通过归纳热泵蒸发经济性数据,得出热泵蒸发平均蒸发能力值,来对比普通多效蒸发热泵流程与间隔式多效热泵流程在蒸汽经济性上的数值大小.计算结果说明,普通多效蒸发热泵流程与间隔式多效热泵流程在蒸汽经济性上非常接近,但间隔式多效热泵流程的总温差远远小于普通多效蒸发热泵流程总温差.间隔式多效热泵流程不但可以大幅节能,减少总温差费用支出,还能在更多效保持低温水平,非常适于热敏性物料的低温蒸发浓缩.     

多效蒸发装置节能的新技术-蒸气喷射式热泵-SPZ型泵组合技术

通过论述蒸汽喷射(压缩)式热泵的工作原理、优点及适用范围,作者提出蒸汽喷射式热泵-SPZ型泵组合技术是多效蒸发装置节能的新技术,并提倡在真空制盐多效蒸发系统引进蒸汽喷射式热泵-SPZ型泵组合技术.     

多效蒸发装置节能的新技术：蒸汽喷射式热泵—SPZ型泵组合技术

通过论述蒸汽喷射（压缩）式热泵的工作原理、优点及适用范围，作者提出蒸汽喷射式热泵－ＳＰＺ型泵组合技术是多效蒸发装置节能的工提倡在真空制盐多效蒸发系统引进蒸汽喷射式热泵－ＳＰＺ型泵组合技术。     

多用途的一效蒸发罐蒸汽压力自动调节系统

糖厂蒸发岗位担负着把清糖汁蒸发浓缩的任务,浓缩糖汁是靠蒸汽的热交换进行的。进入一效蒸发的蒸汽压力稳定与否直接关系到糖汁蒸发的速度和糖浆的质量。一效蒸发罐蒸汽压力过低时,热量不足,蒸发速度慢,物料积压过不去,对于一条龙生产的     

并流多效蒸发淡碱浓缩工艺优化设计研究

建立了并流多效蒸发淡碱浓缩工艺优化设计的数学模型。该模型以整个系统 (包括多效蒸发及多级预热两个序贯系统 )的年总费用 (包括系统年操作费用和年设备折旧维修费用 )最小为优化目标 ,以生蒸汽压力、冷凝器真空度、各效蒸发器有效传热温度差为决策变量 ,提出一种新算法———遗传算法结合拉格朗日乘子法求最优解。算例表明 ,生蒸汽压力、冷凝器真空度及淡碱液湿度对优化结果影响显著 ,各效有效传热温度差的影响不显著。优化设计比常规设计可节省年总费用 13 %～ 17%左右。     

热泵式低温蒸发装置

<正> 蒸发浓缩是许多生产过程必不可少的工序之一。蒸发浓缩装置与发酵工业的关系密切,尤其是与发酵食品,它关系到大部分产品的形态。蒸发浓缩是让溶媒蒸发分离,使溶液的量减少而将溶质浓度提高的操作,因为大都是为了分离蒸发潜热较大的水分,耗能很多。因此,历来积极采取节能措施,例如采用多效化或配置热压缩机的多效化等。 节能的方法大体有上述的多效方式,将分离出来的蒸发蒸汽用压缩机加压后作为热源的     

蒸汽压缩机(热泵)工艺应用

文章对多效蒸发、蒸汽喷射器—热泵蒸发、蒸汽压缩机—热泵蒸发以及多级闪蒸等几种蒸发方式进行简单比较;并重点介绍了蒸汽压缩机(热泵)工艺及特点,蒸汽压缩机的选择及设备情况,热泵技术的节能分析、工业应用业绩及前景等。     

热泵蒸发节能减排

通过对多效逆流蒸发与机械再压缩式热泵蒸发的比较,论述了热泵蒸发再节能减排上的巨大应用价值;并给出蒸汽压缩机的最佳压缩比与选型的建议;以煤为参照,从经济上分析了热泵蒸发的应用前景.     

热泵蒸发节能减排

通过对多效逆流蒸发与机械再压缩式热泵蒸发的比较,论述了热泵蒸发再节能减排上的巨大应用价值;并给出蒸汽压缩机的最佳压缩比与选型的建议;以煤为参照,从经济上分析了热泵蒸发的应用前景。     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

Tests of potential functional barriers for laminated multilayer food packages. Part II: Medium molecular weight permeants

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

The Ministry of Environmental Protection Issued "Feasible Technology Guidelines for Pollution Prevention and Control in Wood Pulping Process of the Paper Industry (Trial)" and Two Other Guiding Technical Documents

On December 27t＂, 2013, the Ministry of Environmenta Protection announced that, in order to implement ＂The Environmental Protection Law of the People＇ s Republic of China＂, improve the working system in environmenta protection technologies, and promote technologica advancement in pollution prevention, the Ministry of Environmental Protection sponsored the formulation of three guiding technical documents including ＂Feasible Technology Guidelines for Pollution Prevention and Contro n Wood Pulping Process of the Paper Industry （Trial）＂     

1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China

正On April 29th,2014,Intelli-Tissue EcoEc tissue machine supplied by PMP Group successfully put into operation at Hebei Xuesong Paper Co.,Ltd.,this is the first such kind of paper machine of PMP Group in China.