同向多轴水煤浆气化数值模拟研究

为弥补现有水煤浆气流床气化技术的不足,研发了一种同向多轴煤气化装置,采用Aspen Plus建立了同向多轴水煤浆气化数值模拟模型,分析了水煤浆浓度、氧煤比和碳转化率对煤气化效果的影响。结果表明,随着氧煤比的增加,H_2、CO、有效气含量均先增大后降低,气化温度逐渐升高,最佳氧煤比为0.61,此时有效气含量最大。随碳转化率的升高,CO和H_2含量均增大,气化温度逐渐降低,对于气化炉而言,提高碳转化率可增加有效气含量。水煤浆浓度分别为60%、62%和65%时,有效气(干基)含量分别为81.3%、82.5%和84.2%,水煤浆浓度每提高1%,有效气含量增加约0.6%。     

连续式超临界水中褐煤一焦化废水共气化制氢

采用连续式超临界水反应装置,以褐煤和焦化废水配制的水煤浆为原料,考察了温度(450℃～600℃)和水煤浆浓度(20%～50%)对褐煤-焦化废水在超临界水中连续气化制氢的影响.结果表明,在褐煤一焦化废水超临界水共气化制氢过程中,存在明显的协同效应.在浆浓度为20%,600℃,25 MPa条件下,褐煤-焦化废水共气化的氢气产率和碳气化率比相同条件下二者单独气化的加权平均值分别增加了141.9 mL/g和6.1%.反应温度是影响褐煤-焦化废水超临界水共气化制氢的关键因素,随着反应温度从450℃提高到600℃,氢气的体积分数与产率分别由21.5%和85.3 mL/g增加到42.3%和371.8 mL/g,碳气化率由18.2%增大到29.8%.碳的气化率随水煤浆浓度的升高而降低,最高进浆浓度可达50%(质量分数),无堵塞现象发生.     

基于Aspen Plus的气流床煤粉富氧气化模拟研究

基于Aspen Plus软件的Gibbs自由能最小化法,建立了煤粉在气流床中的富氧气化模型,该模型预测气化温度、产气组分和产气热值,与试验结果吻合良好。利用Aspen Plus的灵敏度分析模块研究氧气体积分数对气化温度、气体组分、产气热值、气体产率、有效气产率、碳转化率、气化效率及煤气污染物的影响,结果表明:随着氧气体积分数的增加,气化温度逐渐升高,H_2,CO和CO_2含量逐渐增加,而N_2的含量逐渐降低,气体产率逐渐降低,有效气产率逐渐增加,产气热值、碳转化率和气化效率逐渐升高。随着氧气体积分数的增加,粗煤气中H_2S的质量浓度逐渐增加。     

GE水煤浆气化炉动力学建模与分析

利用未反应芯缩核模型建立了GE气化炉内气固反应的动力学模型,依据"小室模型"进行了气化炉中物质的质量和热量衡算。模型计算结果与文献值进行了对比,气化炉出口主要气体摩尔分数最大误差不超过2%,表明模型具有一定的合理性。分析了不同氧煤比、水煤浆浓度对合成气组成、温度及冷煤气效率的影响。研究结果表明:随着氧煤比增加,CO含量增加,H2含量减少,CO2含量几乎不变,冷煤气效率先增加后减少,其变化范围为74%~79%;随着水煤浆浓度增加,CO含量增加,H2和CO2含量有所降低,冷煤气效率变化不明显。研究了当氧煤比为0.95、水煤浆浓度为55%时,合成气组分浓度及温度在床层中的分布情况,结果显示:当气化炉高度小于0.5 m时,气化反应发生剧烈,当O2消耗完毕后,合成气温度下降。     

IGCC示范工程煤气化炉的数值模拟

采用Aspen Plus流程模拟软件对某拟建的IGCC示范工程的德士古煤气化炉进行数值模拟,通过考虑碳的不完全转换对计算流程进行了改进,并运用CPD模型预测煤热裂解的产物分布.研究了煤气化炉的重要操作参数(即水煤浆浓度、氧煤比、气化压力和气化温度)对气化结果的影响.在计算区间内,发现高浓度水煤浆浓度范围内,随浓度的增加,煤气的主要成分(H2+CO)的总含量增加.气化温度增大到1400℃左右时,煤气的主要成分随气化温度的进一步增加会趋于一个恒定值.     

水煤浆热解特性及影响因素

水煤浆热解产物的分布、组成和产率对水煤浆的高效燃烧具有重要影响,同时水煤浆热解产生的H_2、CH_4、CO等气体有助于改善脱硝温度窗口,提高脱硝效率。采用高频加热炉对神木煤制成的水煤浆进行热解,测定并分析了热解气的产率和组成成分,探究了热解温度和加热速率对水煤浆热解特性的影响。结果表明,随着温度的升高,水煤浆的除水失重率持续增加,从700～1 200℃增加了约10%,挥发分和热解气体的产率继续增加,从0.50 L/g增加到0.73 L/g,说明水煤浆的热解程度逐渐增加。热解气体的组成主要是H_2、CO、CH_4和CO_2。随着温度的升高,总热解气体中H_2、CH_4、CO_2和CO总体积分数在700～900℃降低,在900～1 100℃保持稳定,1 100℃以上继续下降,从最初700℃时的90%下降到1 200℃时的78%,其中H_2、CO_2和CH_4体积分数呈阶梯式下降,而CO体积分数几乎不变,H_2体积分数下降最明显,约6.1%,而CH_4则下降了约4%,CO_2下降了2.6%左右。随着温度的升高,H_2、CO_2和CH_4产率先增加后减小,峰值出现在1 100℃左右,而CO产率则持续增加。升温速率也影响挥发物的产率,升温速率667℃/min的除水失重率比400℃/min高6%,但总体影响不大。研究结果为掌握水煤浆初级热解产物的形成特征提供了参考。     

木炭水蒸气催化气化制取合成气

以木炭为原料,选用KOH、K₂CO₃、KHCO₃、KNO₃为催化剂,在上吸式固定床气化炉中,进行水蒸气催化气化制取合成气实验。考察了不同催化剂、催化剂用量、水蒸气流量、气化温度对木炭水蒸气气化的炭转化率、产氢率、气体组成体积分数和H₂/CO值的影响。实验通过炭吸收催化剂溶液来负载催化剂,实验结果表明：4种催化剂都可提高木炭气化效率,在浸渍相同质量分数的催化剂溶液下,催化活性顺序为KOH>K₂CO₃>KHCO₃>KNO₃。碳转化率及产氢率都随着催化剂溶液浓度的增加而增大,但浓度过高增加趋势逐渐变缓,催化剂溶液质量分数在4%~6%较为合适。增加水蒸气流量,气体产物中H₂体积分数增大,H₂/CO值增大。升高温度可促进炭气化反应,950℃时碳转化率和产氢率分别达到98.7%和145.23g/kg。实验可得到H₂/CO比1.53~4.09范围间的合成气,可用于合成甲醇、甲烷、二甲醚等燃料。     

玉米秸秆与煤流化床的共气化特性

以玉米秸秆与无烟煤为原料,在循环流化床中进行空气-水蒸汽气化实验,采用预热装置将气化剂(空气、水蒸汽)由常温加热至500℃,考察气化温度、气化剂类型及生物质掺混比对气化燃气组分和热值、气化效率及碳转率等指标的影响.结果表明,提高气化温度可增大碳转化率及气化效率,950℃时无烟煤单独气化效率最高,850℃时玉米秸秆掺混比为20%的混合试样气化效率最高.选择空气-水蒸汽作气化剂时,H2体积分数由1.80%增至15.53%.玉米秸秆掺混比增加可促进CO生成,抑制CO_2生成,掺混比高于40%时会降低燃气热值及碳转化率.空气作气化剂,玉米秸秆掺混比为20%时燃气热值最高,空气-水蒸汽作气化剂,玉米秸秆掺混比40%时燃气热值最高.     

稻壳在水蒸气中气化实验研究

在流化床实验装置上以水蒸气为气化剂,对稻壳进行热解气化的实验研究,分别考察单因素反应温度(500~700℃)、蒸气流量(7~11kg/h)和进料速率(1.2~3.6kg/h)对产气率及其主要组分(H2、CO、CH4、CO2)的影响。实验结果表明:温度的升高可提高气化气产率及气体组分中CH4和H2的含量,同时降低了CO2的含量,随温度升高,CO的含量呈先增加再降低的趋势。蒸气流量和进料速率的增加对产气率影响分别在500℃和700℃呈现出了不同的规律,说明了在不同反应温度下床内起主导作用的反应不同。在700℃,随蒸气流量和进料速率增加,气化气中H2、CO和CO2的含量都有小幅度变化,CH4体积分数稳定在12%左右。在条件考察范围内,当反应温度为700℃、蒸气流量为7kg/h、进料速率为1.2kg/h时,产气率和H2体积分数分别有最大值,为725L/h和18.05%。     

煤与生物质共气化及炭黑的生成特性

在1kg/h规模的常压流化床气化实验系统上,在850℃,900℃和950℃,n(O)∶n(C)分别为1.0,1.1,1.2,1.3和1.4,生物质的质量分数分别为20%和40%的条件下,对某地PRB煤和一种生物质(美国竹柳)的共气化特性进行了研究.结果表明:随着温度的升高,H_2含量(体积分数,下同)逐渐增加,CO和CH_4含量及Q_(HHV)(合成气热值)逐渐减少,合成气产量和碳转化率增加较多.随着n(O)∶n(C)的增加,CO,H_2,CH_4含量和Q_(HHV)呈下降趋势;合成气产量和碳转化率增加.随着生物质比例的增加,CO,H_2,CH_4的含量先减少后增加,Q_(HHV)增加较多,合成气产量和碳转化率增加.n(O)∶n(C)为1.0时的炭黑量要高于n(O)∶n(C)为1.3时的炭黑量.     

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。