低温热解强化煤粉磁选脱硫效果的实验研究

采用自制热解装置对北宿煤进行热解,此装置与传统热解装置相比具有处理量大和操作简便等优势,能够与磁选实验相结合,热解温度400 ℃～700 ℃,氮气流量0.1 L/min,保温时间为30 min,主要研究热解温度对煤粉磁选脱硫效果的影响.结果表明:适当提高热解温度对磁选脱硫是十分有利的,且500 ℃时效果最佳,热解后半焦与原煤相比磁选脱硫率提高近40%;利用XRD分别对原煤、500 ℃半焦及半焦磁选后的精煤进行分析,发现半焦中有强磁性矿物磁黄铁矿(Fe1-xS)生成,精煤中已无黄铁矿,说明热解-磁选脱硫技术能够有效脱除煤中无机硫.依据GB/T215-2003分析试样中硫的形态,发现煤中有机硫含量高且以噻吩硫形式存在,给实现北宿煤低温预处理磁选高效脱硫造成了困难.     

兖州煤热解预脱硫行为(Ⅰ)热解过程中硫的迁移

煤在一定条件下通过热解或部分气化产生可直接用于燃烧的低硫半焦,这一煤燃前预脱硫技术是实现煤炭高效、低污染利用的理想途径之一.在固定床反应器上对兖州煤进行了热解脱硫的研究,在TPD-FPD在线分析装置上分析了兖州煤中硫在热解过程中向气相转移的主要动态特征.结果表明：700℃前,兖州煤中硫向气相的转移出现在两个显著的温度范围,分别在470℃和560℃左右.通过SEM-EDX和XPS光谱分析技术对兖州原煤及其热解半焦中硫的形态及形貌进行了剖析,发现兖州原煤中黄铁矿主要与其他矿物伴生存在,而有机硫的分布极不均匀且以大量噻吩类硫形态存在,并且热解过程中其他形态的硫还向噻吩类硫转移,这就给实现兖州煤的低温高效率脱硫造成了困难.     

半焦基催化剂裂解煤热解产物提高油气品质

利用上段热解下段催化的两段固定床反应器,针对府谷煤研究了半焦和半焦负载Co催化剂对煤热解产物的催化裂解效果。结果表明,半焦和半焦负载钴对热解产物催化裂解后,热解气收率增加,焦油收率降低,但焦油中沸点低于360℃的轻质组分含量提高,轻质焦油收率基本保持不变或略有增加。与煤在600℃直接热解相比,在热解和催化温度均为600℃,采用煤样质量20%的半焦为催化剂时焦油中轻质组分质量含量提高了约25%,轻质组分收率基本不变,热解气体积收率增加了31.2%;在热解温度600℃,催化温度500℃时,采用煤样质量5%的半焦负载钴催化剂,焦油中轻质组分质量收率和含量分别提高了约8.8%和28.8%,热解气体积收率增加了21.5%。煤热解产物的二次催化裂解的总体效果是将焦油中重质组分转化为轻质焦油和热解气。     

H_2气氛中低变质煤微波热解研究

在定制微波炉中进行了H2气氛中低变质煤的微波热解实验研究,系统考察了微波功率、热解时间、煤样粒度和氢气流量等对低变质煤微波热解产品收率及成分的影响.研究表明,低变质煤在微波功率为800W,热解时间为40min,煤样粒度为5mm~10mm,氢气流量为0.4L/min的优化工艺条件下热解,兰炭收率达59.8%,液体产品(煤焦油和热解水)收率达28.2%.热解获得的煤焦油中烷烃类化合物含量高达45.2%,兰炭中酚羟基和羰基官能团含量较高,固定碳含量高,硫和挥发分含量低.     

煤加压富氢热解及半焦气化特性研究

为研究加压固定床气化过程中热解区和气化区的反应,模拟固定床富氢气氛热解与半焦气化过程,利用加压富氢热解装置考察了压力、加热终温以及富氢比例对煤热解的影响,分析了各因素对热解影响的机理,以富氢气氛热解半焦为原料,通过加压热重分析仪进行试验研究,研究不同温度和不同热解半焦原料的条件下碳转化率与CO_2反应速率随时间的变化规律,分析富氢比例对气化反应活性的影响。结果表明:常压富氢气氛热解试验中,随着富氢比例的升高,提供大量H,H浓度增大,煤在热解过程中自由基会不断与H结合生成稳定组分,其中包括大量小分子的挥发物以及部分焦油析出,使半焦中挥发分降低0.69%,半焦收率降低4.8%;加压条件下半焦收率较高,半焦收率随压力的增大变化幅度不大,且没有明显规律,挥发分总体逐渐降低,但变化较小;随着终温的升高,挥发分析出量逐渐升高,伴随着挥发分析出,富氢氛围中的H将与自由基结合生成小分子结构而逸出,半焦收率与挥发分均逐渐降低;增加富氢比例能提高半焦的成熟程度,富氢比例由0增加到35%,H浓度增大,煤中小分子可迅速加氢生成挥发物,同时大分子也会加氢变为稳定结构,半焦挥发分降低了1.46%,半焦收率降低了2.50%;富氢热解能明显促进CO和CH_4的生成,在35%H_2时产量分别达到91.2和63.8 mL/g。由气化特性试验可知:提高气化反应温度,有助于提高富氢半焦与CO_2的气化反应性;富氢气氛与惰性气氛下热解半焦的气化反应活性相近,表明加氢热解能够提高焦油产率与焦油品质,同时对半焦的气化活性影响不大。     

高硫煤与生物质共热解脱有机硫研究

选取渭北石炭纪高有机硫煤与小麦秸秆进行共热解实验,采用正交实验考察了热解温度、升温速率、停留时间和煤与生物秸秆的混合比以及煤与生物秸秆成型压力等对热解脱有机硫及有机硫脱除规律的影响.结合FTIR和SEM分析了共热解半焦的结构特征、孔隙结构与发育情况,并讨论了低温溶剂萃取精制对煤与生物质共热解脱硫效果的影响.结果表明,热解温度对脱硫率的影响最显著.共热解制备较高脱硫率半焦所适宜的最佳水平为850℃,15℃/min,5min,1∶4和2MPa.共热解半焦孔结构发育整齐规则,孔壁薄,孔径较大,有利于热解过程中硫的析出与扩散.低温溶剂萃取提高了共热解脱硫率,尤其是热水精制煤与生物秸秆共热解脱硫率约为39%.     

半焦催化裂解原位煤热解焦油的研究

在两段固定床反应器内考察了不同半焦对府谷煤热解产物的催化裂解效果。结果表明,不同半焦对煤热解产物催化裂解后,焦油收率降低,但焦油中沸点低于360℃的轻质组分质量分数明显增高。与煤在600℃直接热解相比,在热解和催化温度均为600℃时,采用煤样质量20%的半焦为催化剂时催化效果最好,其中轻质焦油收率基本不变,焦油中轻质组分质量分数提高了25%。半焦的表面结构和灰分都对煤热解产物的催化裂解有一定效果。在比表面积较低时,半焦中的灰分对原位煤热解焦油的裂解作用比较明显;随着比表面积的增加,灰分的影响越来越弱,半焦表面结构的影响越来越明显。     

褐煤半焦热解温度对其加氢制甲烷活性的影响

利用固定床热解炉在不同热解温度(400~900℃)下制得热解半焦,采用BET和XRD分析手段对不同热解温度的褐煤半焦理化性质进行表征。在高温高压(800℃、4 MPa)条件下,利用固定床反应器对呼伦贝尔褐煤半焦试样进行直接加氢制甲烷的研究。结果表明,呼伦贝尔褐煤半焦在高温高压加氢制甲烷的最优热解温度为600℃;热解温度在600~800℃的半焦加氢反应碳转化率可达82%,产品气中CH_4的质量分数约96%;在400~800℃,半焦比表面积由8 m2/g增大到182 m~2/g,半焦加氢反应碳转化率随比表面积的增大而增加,当热解温度高于800℃,半焦中碳结构的晶面间距d002减小,堆垛高度L002明显增大,d002/L002从0.472迅速减小为0.365,石墨化程度加深,导致其加氢反应碳转化率迅速下降。     

淖毛湖煤加氢热解产物特性及半焦气化反应性

在加压固定床反应器中进行淖毛湖煤在常压和1.5 MPa氢气和氮气中的热解试验,利用多种表征方法对比研究了氢气和氮气下的热解产物产率和组成及半焦结构的变化,并利用热重分析研究热解半焦的CO₂气化反应性。结果表明：与常压N₂中热解相比,煤在加压的H₂中热解可有效提高热解气体中CH₄和C₂～C₃的产率,在800℃热解CH₄和C₂～C₃的体积产率分别由53.5和16.6 mL/g增至345.6和20.8 mL/g。焦油和轻质焦油产率也有效提升,在600℃下,与常压N₂中热解相比,1.5 MPa H₂中煤热解的焦油产率由19.3%升至22.8%,焦油中脂肪烃含量由35.5%降至14.8%,单环芳烃含量由8.3%增至28.9%,轻质焦油质量分数和产率分别升至95.0%和21.8%。半焦的N₂吸附和拉曼光谱分析结果表明,煤在加压H_...     

半焦床层温度对煤-半焦耦合热解制取低温焦油的影响

以半焦在相对高温下发生缩聚反应析出的氢作为氢源,在同一反应器内实现了煤-半焦耦合条件下的含氢气氛煤解聚过程,研究了半焦床层在不同温度(650℃,700℃和750℃)下对煤热解产物分布及其品质的影响.结果表明:耦合热解(CSP)过程较单煤热解(CP)过程的焦油产量增加,且随着半焦床层温度的升高而逐渐增大,750℃时焦油收率提高了16%.焦油模拟蒸馏实验表明,耦合热解过程的焦油中轻质组分含量增加,沥青组分含量显著减少,半焦床层温度在650℃(CSP650),700℃(CSP700)和750℃(CSP750)时,CSP过程沥青含量比CP过程沥青含量分别降低了28.83%,40.77%和44.28%.焦油的GC×GC-MS联用实验表明,耦合热解焦油的芳香环侧链取代结构物质含量增加.原煤半焦的TG-MS实验表明,半焦在高温热解时由于发生裂解、缩聚反应而析出H_2和CH_4,这是本研究中加氢热解的氢源.     

Insect antifeedant properties of anthranoids from the genusVismia

Vismiones and ferruginins, representatives of a new class of lypophilic anthranoids from the genusVismia were found to inhibit feeding in larvae of species ofSpodoptera, Heliothis, and inLocusta migratoria.     

Direct observation of freeze-thaw instability of latex coatings via high pressure freezing and cryogenic SEM

Despite its industrial importance, the subject of freeze-thaw (F/T) stability of latex coatings has not been studied extensively. There is also a lack of fundamental understanding about the process and the mechanisms through which a coating becomes destabilized. High pressure (2100 bar) freezing fixes the state of water-suspended particles of polymer binder and inorganic pigments without the growth of ice crystals during freezing that produce artifacts in direct imaging scanning electron microscopy (SEM) of fracture surfaces of frozen coatings. We show that by incorporating copolymerizable functional monomers, it is possible to achieve F/T stability in polymer latexes and in low-VOC paints, as judged by the microstructures revealed by the cryogenic SEM technique. Particle coalescence as well as pigment segregation in F/T unstable systems are visualized. In order to achieve F/T stability in paints, latex particles must not flocculate and should provide protection to inorganic pigment and extender particles. Because of the unique capabilities of the cryogenic SEM, we are able to separate the effects of freezing and thawing, and study the influence of the rate of freezing and thawing on F/T stability. Destabilization can be caused by either freezing or thawing. A slow freezing process is more detrimental to F/T stability than a fast freezing process; the latter actually preserves suspension stability during freezing. Presented at the 82nd Annual Meeting of the Federation of Societies for Coatings Technology, October 27–29, 2004 in Chicago, IL. Tied for first place in The John A. Gordon Best Paper Competition.     

Ethanol and (−)-α-Pinene: Attractant Kairomones for Bark and Ambrosia Beetles in the Southeastern US

In 2002–2004, we examined the flight responses of 49 species of native and exotic bark and ambrosia beetles (Coleoptera: Scolytidae and Platypodidae) to traps baited with ethanol and/or (−)-α-pinene in the southeastern US. Eight field trials were conducted in mature pine stands in Alabama, Florida, Georgia, North Carolina, and South Carolina. Funnel traps baited with ethanol lures (release rate, about 0.6 g/day at 25–28°C) were attractive to ten species of ambrosia beetles (Ambrosiodmus tachygraphus, Anisandrus sayi, Dryoxylon onoharaensum, Monarthrum mali, Xyleborinus saxesenii, Xyleborus affinis, Xyleborus ferrugineus, Xylosandrus compactus, Xylosandrus crassiusculus, and Xylosandrus germanus) and two species of bark beetles (Cryptocarenus heveae and Hypothenemus sp.). Traps baited with (−)-α-pinene lures (release rate, 2–6 g/day at 25–28°C) were attractive to five bark beetle species (Dendroctonus terebrans, Hylastes porculus, Hylastes salebrosus, Hylastes tenuis, and Ips grandicollis) and one platypodid ambrosia beetle species (Myoplatypus flavicornis). Ethanol enhanced responses of some species (Xyleborus pubescens, H. porculus, H. salebrosus, H. tenuis, and Pityophthorus cariniceps) to traps baited with (−)-α-pinene in some locations. (−)-α-Pinene interrupted the response of some ambrosia beetle species to traps baited with ethanol, but only the response of D. onoharaensum was interrupted consistently at most locations. Of 23 species of ambrosia beetles captured in our field trials, nine were exotic and accounted for 70–97% of total catches of ambrosia beetles. Our results provide support for the continued use of separate traps baited with ethanol alone and ethanol with (−)-α-pinene to detect and monitor common bark and ambrosia beetles from the southeastern region of the US.     

Methyl 2,4,6-decatrienoates Attract Stink Bugs and Tachinid Parasitoids

Halyomorpha halys (Stål) (Pentatomidae), called the brown marmorated stink bug (BMSB), is a newly invasive species in the eastern USA that is rapidly spreading from the original point of establishment in Allentown, PA. In its native range, the BMSB is reportedly attracted to methyl (E,E,Z)-2,4,6-decatrienoate, the male-produced pheromone of another pentatomid common in eastern Asia, Plautia stali Scott. In North America, Thyanta spp. are the only pentatomids known to produce methyl 2,4,6-decatrienoate [the (E,Z,Z)-isomer] as part of their pheromones. Methyl 2,4,6-decatrienoates were field-tested in Maryland to monitor the spread of the BMSB and to explore the possibility that Thyanta spp. are an alternate host for parasitic tachinid flies that use stink bug pheromones as host-finding kairomones. Here we report the first captures of adult and nymph BMSBs in traps baited with methyl (E,E,Z)-2,4,6-decatrienoate in central Maryland and present data verifying that the tachinid, Euclytia flava (Townsend), exploits methyl (E,Z,Z)-2,4,6-decatrienoate as a kairomone. We also report the unexpected finding that various isomers of methyl 2,4,6-decatrienoate attract Acrosternum hilare (Say), although this bug apparently does not produce methyl decatrienoates. Other stink bugs and tachinids native to North America were also attracted to methyl 2,4,6-decatrienoates. These data indicate there are Heteroptera in North America in addition to Thyanta spp. that probably use methyl 2,4,6-decatrienoates as pheromones. The evidence that some pentatomids exploit the pheromones of other true bugs as kairomones to find food or to congregate as a passive defense against tachinid parasitism is discussed.     

2007～2008年世界塑料工业进展

收集了2007年7月～2008年6月世界塑料工业的相关资料,介绍了2007～2008年国外塑料工业的发展情况,提供了世界塑料产量、消费量及全球各类树脂的需求量及产能情况.按通用热塑性树脂(聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂)、工程塑料(尼龙、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚)、特种工程塑料(聚苯·硫醚、液晶聚合物、聚醚醚酮)、通用热固性树脂(酚醛、聚氨酯、不饱和聚酯树脂、环氧树脂)不同品种的顺序,对树脂的产量、消费量、供需状况及合成工艺、产品应用开发、树脂品种的延伸及应用的进一步扩展等技术作了详细介绍.     

2005～2006年国外塑料工业进展

收集了2005年7月～2006年6月国外塑料工业的相关资料,介绍了2005—2006年国外塑料工业的发展情况。提供了世界塑料产量、消费量及全球各类树脂生产量以及各国塑料制品的进出口情况。作为对比,介绍了中国塑料的生产情况。按通用热塑性树脂（聚乙烯、聚丙烯、聚苯乙烯、聚氯乙烯、ABS树脂）、工程塑料（聚酰胺、聚碳酸酯、聚甲醛、热塑性聚酯、聚苯醚）、通用热固性树脂（酚醛、聚氨酯、不饱和树脂、环氧树脂）、特种工程塑料（聚苯硫醚、液晶聚合物、聚醚醚酮）的品种顺序,对树脂的产量、消费量、供需状况及合成工艺、产品开发、树脂品种的延伸及应用的扩展作了详细的介绍。