粗浆洗涤方法和洗浆机理的研讨

粗浆洗涤是制浆造纸生产中的重要环节,对于提高黑液碱回收率,减少排水污染,起着关键的作用。为从洗浆工艺、设备创新开发的源头上着手。进行系统研究,分别对稀释-浓缩、置换、稀释-浓缩加置换、稀释-浓缩加置换及挤压4种洗浆段和洗浆系统组成的方法、机理进行了研讨,导出了洗浆效率等计算式,分析了各类洗浆设备和系统的优缺点,提出了改进意见和发展方向,可为洗浆技术、设备核心技术的创新研发提供参考。     

三种洗浆机洗浆效果比较

硫酸盐法制浆需将蒸煮后的纸浆经过洗浆机提取黑液.我厂现有三种洗浆设备:真空洗浆机、压力洗浆机和置换洗装机.由于这三种洗浆机装备水平不同,洗涤效率也各异.为比较这三种洗浆设备的效率和环保效益,我们对这三种洗浆机洗后浆料中的可洗碱、水溶性COD和总固形物进行了测定.     

现代浆厂洗浆设备的综合评价及应用选择

纸浆洗涤是造纸企业实现节能降耗和清洁生产的关键环节,种类繁多的洗浆设备对项目建设时的洗浆设备选择带来了难度。本文根据洗浆设备的功能特点,结合成熟运行的项目经验,阐明现代浆厂主要洗浆设备可在双辊置换压榨挤浆机、鼓式置换洗浆机和鼓式真空洗浆机3类设备内选择或优化组合,概括了洗浆设备配置理念并提出了洗浆设备的选择建议。     

置换压榨洗浆机在大中型浆厂中的应用

介绍了置换压榨类洗浆机的机理、结构和特点,探讨了该类洗浆设备在大、中型浆厂中的应用场所、系统组成、工作要点及发展前景。     

一种新型黑液提取设备──双辊螺旋挤浆机

牡丹江造纸厂制浆车间阔叶木浆的黑液提取设备主要是水平带式真空洗浆机，靠置换作用来完成黑液的提取和粗浆的洗涤，由于多种因素的影响，黑液提取率较低，基本在80％左右，且洗浆效果不稳定，为解决这一问题，工厂于1996年在车间安装了一台新型的黑液提取设备──双辊螺旋挤浆机。与传统的螺旋挤浆机所不同的是，这种机械挤压式脱水设备的主要脱水元件为两根同向旋转的变矩螺旋，按照挤浆过程中进浆区、低浓区、高浓区三部分浆浓的变化分为三个区段。近年来，国际上黑液提取设备逐渐向高浓挤压式方向发展，这种同向螺旋挤浆机的主要部件的…     

金海浆纸公司制浆生产线洗浆机全部安装完成

近日，金海浆纸公司制浆生产线洗浆机全部安装完成。制浆生产线共有9台压力置换洗浆机．所有设备均采用世界最先进技术。该洗浆机可以将酸性漂白阶段和碱性漂白阶段分开，洗涤后的滤液可以回用作稀释液．减少了废水的排出量，既提高洗涤质量又能降低生产成本，减轻环保压力。     

水平式洗浆机——赴加拿大、美国考察造纸报告

水平式洗浆机是70年代初期开发的一种新型洗浆机。过去,用于化浆的洗浆设备,绝大多数是传统的鼓式真空洗浆机或鼓式压力洗浆机。这两种常用的洗浆设备一般是多台逆流串联使用,废液中溶解性的固形物是利用扩散和置换原理进行抽出。而水平式洗浆机则只是置换抽出。因此,水平式洗浆机与传统的鼓式洗浆机相比,在很多方面有其明显的优越性。本文是根据近几年来与外国公司进行技术座谈以及我们于1985年3月27日至5月2日赴加拿大和美国对水平式洗浆机进行技术考察(共看了6台在运行),并参     

维美德浆料洗涤设备——TwinRoll PressTM的发展历程及前景

TwinRoll Press~(TM)是维美德公司研发的专利设备,全称为双辊洗浆机。作为浆线关键的洗浆设备,双辊洗浆机在制浆洗选漂系统中起到了举足轻重的作用。本文简要介绍了双辊洗浆机的发展历程以及每一代洗浆机的特点和应用,并重点介绍了第五代TRP Evolution~(TM)(改进型双辊洗浆机)的竞争优势、设备特点以及市场应用情况。     

粗浆洗涤新设备—鼓式置换洗浆机

一种新型的粗浆洗涤设备一鼓式置换洗浆机(以下简称DD洗浆机)已在芬兰的Enso-Gutzeit和Kymmene两纸厂运转成功。这两个厂原有洗浆机能力不够,又没有足够空间增加原样洗浆机的台数,因此决定安装新型的DD洗浆机。DD洗浆机是在一个洗鼓里完成4段置换洗涤,不需要添加中间滤液槽。其特点是浆层两边的压力差是来自洗涤水本身压力,不需形成真空。因此Kymmene造纸厂安装新设备后,由于带进的空气量显著降低,因此再也不必使用消泡剂。 Kymmene造纸厂原有洗浆线共有26条     

中浓鼓式置换洗浆机的结构及调试运行

中浓鼓式置换洗浆机是国外开发的新型洗浆设备。文章介绍了该设备的结构特点，洗涤原理安装及调试运行情况。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

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

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the