SCR脱硝效率的主要影响因素分析

氮氧化物造成的大气污染日益严重,目前燃煤电厂普遍采用SCR技术进行脱硝。文章着重介绍了SCR烟气脱硝效率的影响因素,其主要影响因素为：催化剂、反应温度、空间速度、反应时实际摩尔比、反应物混合程度等。     

SNCR脱硝装置对燃煤链条锅炉运行的不利影响及应对措施

近年来由于环保标准的提高,燃煤锅炉产生的烟气除了需要进行除尘脱硫处理外,还需进一步安装烟气脱硝装置,对燃煤锅炉烟气中的氮氧化物进行处理,燃煤锅炉烟气脱硝广泛采用的技术主要有SNCR、SCR和SNCR/SCR混合法等脱硝技术。目前链条燃煤锅炉从实用性和投资费用考虑,基本上都采用SNCR脱硝装置进行锅炉烟气脱硝。SNCR脱硝装置的使用会对链条燃煤锅炉及附属设备产生诸多影响,为了保证链条燃煤锅炉及附属设备的正常安全运行,必须采取相应的措施将SNCR脱硝装置对链条燃煤锅炉的不利影响控制在合理范围内。本文针对SNCR脱硝装置对链条燃煤锅炉产生的不利影响和具体应对解决措施进行分析讨论。     

对集中供热锅炉烟气脱硝技术的研究

近年来,随着社会的进步和经济的发展,环境问题的全球化使得生态环境保护越来越受到社会各界的广泛关注。其中,大气污染作为造成环境污染的重要因素之一,其形势刻不容缓,已逐渐成为全球环境问题研究的重要课题。氮氧化物气体是危害最大也是最难处理的大气污染物之一,重要来源于燃煤过程。目前,我国煤炭资源的使用仍在国民经济发展中占有重要地位,供电、供暖等行业对于燃煤的大量需求带来的氮氧化物的产生使得我国大气污染形势十分严峻,这就要求必须运用科学合理的烟气脱硝技术对燃煤所产生的气体进行脱硝处理,从而防止氮氧化物带来的大气污染,从根本上实现大气环境保护。本文主要针对集中锅炉的烟气脱硝技术进行了研究,阐述了集中锅炉的烟气脱硝技术的内涵,论述了集中锅炉的烟气脱硝中对锅炉的改造,分析了集中供热锅炉的烟气脱硝技术中SCR工艺技术的优化,并提出了尿素热解制氨技术,探讨了其控制策略的开发。     

对集中供热锅炉烟气脱硝技术的研究

近年来,随着社会的进步和经济的发展,环境问题的全球化使得生态环境保护越来越受到社会各界的广泛关注。其中,大气污染作为造成环境污染的重要因素之一,其形势刻不容缓,已逐渐成为全球环境问题研究的重要课题。氮氧化物气体是危害最大也是最难处理的大气污染物之一,重要来源于燃煤过程。目前,我国煤炭资源的使用仍在国民经济发展中占有重要地位,供电、供暖等行业对于燃煤的大量需求带来的氮氧化物的产生使得我国大气污染形势十分严峻,这就要求必须运用科学合理的烟气脱硝技术对燃煤所产生的气体进行脱硝处理,从而防止氮氧化物带来的大气污染,从根本上实现大气环境保护。本文主要针对集中锅炉的烟气脱硝技术进行了研究,阐述了集中锅炉的烟气脱硝技术的内涵,论述了集中锅炉的烟气脱硝中对锅炉的改造,分析了集中供热锅炉的烟气脱硝技术中SCR工艺技术的优化,并提出了尿素热解制氨技术,探讨了其控制策略的开发。     

甘蔗糖厂纯蔗渣锅炉烟气SNCR脱硝工艺技术的应用探索

介绍了SNCR脱硝工艺技术首次在甘蔗糖厂锅炉烟气脱硝中的应用,以及对SNCR与SCR脱硝工艺在技术、应用等方面进行了比较。生产运行表明,采用SNCR脱硝工艺技术后锅炉烟气烟尘氮氧化物排放浓度≤100 mg/m3,达到GB13223-2011排放标准的要求。     

华泰热力脱硝项目竣工投运

正2014年11月13日,华泰热力2×135 MW机组脱硝项目竣工典礼举行。该项目总投资7000万元,包括增上炉内低氮燃烧改造系统,炉外建设SCR(选择性催化还原技术)脱硝系统等相应公用辅助设施。项目投运后,氮氧化物排放浓度从以前最高时的600 mg·m-3下降到80 mg·m-3以下,每年可减排氮氧化物2000多t,对当地及周边大气环境质量改善具有积极的推动意义。值得一提的是,该项目采用的SCR技术是韩国电力株式会社与中国在烟气脱硝方面的第一个     

关于燃煤锅炉低氮燃烧与脱硝系统优化运行的探讨

随着全球化的环境问题越来越明显,社会各界也在高度的关注着生态环境保护工作,而为了有效地降低燃煤锅炉烟气中的氮氧化物,其主要手段就是采用锅炉内的低氮燃烧和烟气脱硝技术,我们应全面的掌握燃料燃烧过程中NOx的生成原理和控制方法,以具体的电厂为例,深入的研究燃煤锅炉低氮燃烧和脱硝系统的优化改造技术,分析能够有效减少NOx排放的技术特点和工艺流程,从而真正地实现燃煤锅炉的经济运行。文章针对低氮燃烧系统和SCR脱硝系统的应用以及应用低氮燃烧和SCR脱硝技术的总体效果两个方面的内容进行了详细的分析和探析,从而详细的论述了如何实现燃煤锅炉低氮燃烧和脱硝系统的优化运行。     

SCR技术在600兆瓦火电机组中的应用

通过某600MW火电厂SCR烟气脱硝技术的实际应用,介绍火电厂NOx的形成机理,SCR法脱硝技术的工艺、系统构成、催化剂、以及影响SCR法烟气脱硝的因素及实际运行状况和注意事项。     

烟气脱硫脱硝技术的现状与发展探讨

烟气中所含有的硫、硝成分对空气会产生严重的污染影响,所以烟气脱硫脱硝技术是处理二氧化硫、氮氧化物等废弃物的重要方式,对于保护环境具有重要作用.本文阐述了烟气脱硫脱硝技术的重要意义,并通过分析烟气脱硫技术现状、烟气脱硝技术现状以及同时脱硫脱硝技术的现状,对烟气脱硫脱硝技术使用炭基新型催化技术进行展望,探讨了改性海水法技术的发展前景,争取实现更有效的烟气脱硫脱硝效果,以减少对空气的污染.     

脱硝技术及研究进展

综述目前国内外主要的脱硝技术和研究进展,其中包括SCR法、SNCR法、炽热碳法等还原法,介绍稳定性二氧化氯法、臭氧法等氧化法以及固体吸附法、液体吸收法、电解吸收法等吸收法以及今后可能被应用的几种新型的脱硝技术。在对各种脱硝技术去除氮氧化物的方法原理进行分析的基础上,比较各种方法的优缺点,并对今后脱硝技术的发展趋势进行展望。     

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.