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春节前后,吉安市遭遇到罕见的冰冻雨雪灾害天气,连续出现了低温、阴雨和雨夹雪,成为全省灾情最严重地区之一.特别是1月25日以后,出现了持续大范围的雨雪冰冻天气.冰冻损坏了市区的电网,压垮了树枝,封锁了道路和桥梁. 相似文献
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收集了2010年7月~2011年6月世界塑料工业的相关资料,介绍了2010~2011年世界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、聚氯乙烯、聚苯乙烯、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、不饱和聚酯树脂、环氧树脂、聚氨酯)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。 相似文献
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2003~2004年国外塑料工业进展 总被引:5,自引:0,他引:5
收集了2003年7月~2004年6月国外塑料工业的相关资料,介绍了2003年~2004年国外塑料工业的发展情况,提供了世界几大区域塑料的产量、增长率及所占份额,美国、德国、日本、韩国、法国、比利时、中国台湾、加拿大、巴西、西班牙等国家和地区的不同树脂的产量及消费量,各国、各地区塑料原料的产量、进出口量、国内消费量和人均消费量,日本塑料原料的生产情况。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。 相似文献
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萜类化合物具有可观的经济价值,但是目前的生产过程复杂、产量低。酿酒酵母甲羟戊酸途径为萜类化合物的合成提供直接前体,因此酿酒酵母细胞具有合成异源萜类化合物的天然优势。对酿酒酵母甲羟戊酸途径的清晰认识是对其进行有效利用的基础,本文从代谢途径、关键酶的特点和全局调控机制3个方面对该途径进行了介绍。从代谢途径的构建和优化、模块与底盘细胞的适配、模块构建及组装方式的角度概述了酿酒酵母细胞异源合成单萜、倍半烯萜、二萜、三萜类化合物的研究进展。指出实现酿酒酵母高效合成萜类化合物所需要解决的基础问题是对酿酒酵母甲羟戊酸途径进行更为全面了解和对萜类化合物的天然代谢途径进行明确解析;另外,合成生物学的进一步发展也将为此提供应用基础。 相似文献
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我公司回转窑规格为Φ4.0m×60m.窑内使用的耐火砖为镁铬砖、隔热尖晶石、蓝晶石和黏土砖以及硅莫砖.镁铬砖规格为(81×90×150×200)mm,其它耐火砖规格皆为(81×90×200×200)mm.尽管每个品种的砖品质相同,但由于在镶砌和使用过程中方法不同,寿命有长有短.通过多年实践,现总结如下. 相似文献
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分析中药渣中的水分,阐述中药渣受挤压作用时的脱水机理,结合中药渣的特性和带式压滤机的脱水工艺,对压滤机的布料器进行改造,增加两级分料螺旋,改善压滤效果,使其适用于中药渣脱水试验,增加物料处理量,减少溢料现象,降低污水含固率,减少运行人员劳动强度。采用控制变量法,试验研究压滤机的不同脱水段、压力、带速、中药渣初始含水率等4个因素对脱水效果的影响,结果表明:物料初始含水率越大,不同脱水段的脱水率越大,滤饼的含水率越大;Ⅰ级脱水辊对物料脱水效果影响最大,楔形预压段对物料脱水效果影响最小;中药渣的初始含水率不宜超过80.16%;Ⅰ级脱水辊压力选择0.2~0.6MPa较合适;带速在0.3~0.5m/s范围内时,滤饼的含水率在65%~ 66%之间,脱水效果较好。 相似文献
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Melissa L. E. Gutarra Mateus G. Godoy Leda R. Castilho Professor Denise M. G. Freire 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2007,82(3):313-318
Two alternative inoculation strategies for lipase production by the fungus Penicillium simplicissimum were tested in solid‐state fermentation using a residue from the babassu oil industry (babassu cake). Conventional spore inoculation was compared with fungal pellets grown in liquid medium and with inocula consisting of fermented cake. Fungal pellets delayed lipase production whereas fermented cake accelerated enzyme synthesis, yielding a productivity of 0.45 U g?1 h?1, which is equivalent to the highest values obtained with conventional inocula. Therefore, a 22 factorial design was used to determine the best conditions for lipase production with fermented cake as inoculum strategy, varying the inoculum propagation time and inoculum concentration. Lipase activity and productivity reached 30 U g?1 and 0.63 U g?1 h?1, respectively, with 10% inoculum and 36 h. Thus, fermented cake inocula increased production 1.5‐fold with 10 times fewer spores than in conventional inoculation, indicating that fermented solids are an interesting alternative for inoculum development in solid‐state fermentation, mainly for large‐scale processes. Copyright © 2007 Society of Chemical Industry 相似文献
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MS Hameed 《Filtration+Separation》2002,39(5):45-47
This paper proposes design steps for a crossflow filtration system. The design s procedure is based primarily upon the particle size of the suspended matter, suction velocity, solid and liquid densities, liquid viscosity, filter cake thickness and the specific resistance of the filter cake. The critical shear stress is used to work out the design parameters such as axial velocity, pipe diameter or duct dimensions, filtration pressure and filtration area. 相似文献
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The aim of this study is to develop a new approach to green plant fractionation using twin-screw extrusion, leading to the production of a green filtrate, rich in proteins and a solid fibrous residue, rich in cellulose. The influence of the screw profile on protein recovery in the liquid extract and on plant dehydration was characterized. Two screw profiles were tested, at different temperatures and liquid/solid ratios. Increasing the shearing action on the plant produces a liquid extract richer in protein; from 25% of dry matter to 31% of dry matter when two additional sections of paddle screw elements are inserted onto the screw profile. However, it leads to higher liquid retention in the alfalfa fibers and thus dehydration of the plant is less efficient. The fibrous residue still contains at least 60% humidity when the alfalfa is highly degraded, whereas less than 47% humidity remain with only one section of bilobe paddle screws on the profile. For the two screw profiles tested, the crucial parameter influencing the fraction quality (protein content of the filtrate, dry matter content of the fibrous residue) is the liquid/solid ratio. 相似文献
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从太湖水系灌溉的水稻田中分离出一株细菌XXG作为受试菌株,通过分析其形态特征表现、生理生化实验及16SrDNA序列确定菌属;对培养基投加比、菌藻体积比、菌密度、藻密度进行单因素试验,研究各因素对溶藻效果的影响;选择温度(X1)、pH(X2)、摇床转速(X3)3个主要因素采用Box-Behnken Design (BBD)设计,优化影响溶藻率的环境因素;通过对比菌体重悬液和无菌发酵液对藻液的影响,初步探究其溶藻方式。实验结果表明,XXG菌与Paenibacillus sp. KU573975相似高达99.27%,初步判定该菌株为类芽孢杆菌(Paenibacillus);最佳菌藻体积比为5.6%,XXG菌对处于对数生长期前期的铜绿微囊藻液的6 d溶藻率达77.1%;影响XXG溶藻率的3个重要环境因素具有交叉作用,得出溶藻率与温度、pH、摇床转速的二次回归模型,该模型P<0.0001,R2=0.9727,在最佳溶藻特性下,当温度为30℃、pH=7.5、摇床转速为150 r/min时溶藻率最高,溶藻率可达92.02%;无菌发酵液仍有溶藻效应,推测XXG菌的主要溶藻方式为间接溶藻,无菌发酵液相较于细菌发酵液产生溶藻效应的减弱可能由细菌发酵液中的菌体继续分泌某种溶藻活性物质来实现。 相似文献
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通过热重实验研究N2气氛下升温速率对索氏提脂后的小球藻热解特性的影响,利用管式炉在N2气氛下快速热解实验得出:在400℃时,小球藻热解转化率最高,生物油产率达57.6%,热解气为10%。采用等转化率方法FWO和KAS法对藻渣热解动力学进行分析和比较,结果表明:藻渣热解的主要热解阶段为25~800℃,可分为3个阶段,藻渣的DTG曲线存在两个失重峰,且随着升温速率提高,TG和DTG曲线都向高温区偏移,最大失重速率和残余固体质量都增加。N2气氛条件下藻渣的主要热解阶段表观活化能和指前因子分别为228.46 kJ/mol和2.49×1021 min-1,此阶段下FWO法和KAS法均能很好模拟藻渣热解数据,线性拟合相关系数(R2)均在0.96以上,最佳热解函数为dα/dT=2.49×1021/β exp(-228.46/(RT))(1-α)8。 相似文献
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The objective of this study was to determine lipid and biomass distribution during aqueous and alcohol processing of oleaginous
microalgae, with the intention of fully extracting lipid from the dewatered cell paste. Two species, Nannochloropsis and Schizochytrium, were used. It is shown that most of the total lipid, 73% for Nannochloropsis and 87% for Schizochytrium, was held by the cell solids obtained by centrifugation during the aqueous process, justifying the need to develop a more
effective lipid-extraction method. Use of ethanol at elevated temperature enabled efficient extraction of lipid from the cell
mass and at the same time improved biomass precipitation and recovery in the solid or cake fraction. More than 68 and 95%
of total lipid was recovered on a 50-g scale (as-is paste basis) from Nannochloropsis and Schizochytrium, respectively. Approximately 65% of the biomass was recovered in the solid fraction for both algae from the alcohol process,
compared with the much lower biomass recovery, 38 and 16% for Nannochloropsis and Schizochytrium by the aqueous process. Therefore, oil and biomass fractionation by use of pure water is far less effective than fractionation
by use of alcohol, and the alcohol process has great promise in algal oil recovery. 相似文献
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Alfalfa was studied to define a new approach for green plant fractionation using twin-screw extrusion, leading to the production of a green filtrate, rich in proteins and a solid fibrous residue, rich in cellulose. The influence of the screw profile on protein recovery in the liquid extract and on plant dehydration was characterised. Three screw profiles were tested, at different liquid/solid ratios and plant inlet flow rates. A significant difference was determined, at a confidence level of 95%, between the influence of the three profiles on alfalfa dehydration and protein extraction in the raw filtrate. When mechanical action on the plant is stronger, both protein recovery and solid dehydration are better with more than half of the initial proteins (50.8%) recovered in the liquid extract in the best screw configuration (profile 3). However, extrusion is not efficient for the plant dehydration but the interest of adding a second filtration zone was demonstrated; after the first pressing and liquid expression in a first stage, water is added to the residual matter, which leads to a better protein extraction in the second filtration stage. 相似文献
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分析了升平煤矿选煤厂煤泥粒度组成,发现浮选入料中高灰细泥含量高,增加了煤泥脱水的难度。在论述颗粒直径与浮选特性、药剂消耗关系的基础上,对选煤厂浮选精煤粒度组成进行了分析,说明细粒煤对浮选精煤污染严重。浮选入料细粒煤泥过多造成了选煤厂滤饼水分、滤液浓度高,煤泥水性质恶化,过滤机吸料差,处理能力低,并针对上述问题,将原有PG78-8圆盘真空过滤机更换为GPJ-96加压过滤机对选煤厂进行了改造。改造完成后,GPJ-96加压过滤机的入料质量分数和滤液质量分数均低于PG78-8圆盘真空过滤机,且滤饼质量分数远大于PG78-8圆盘真空过滤机,可见GPJ-96加压过滤机煤泥压滤效果较好;GPJ-96加压过滤机的固体产率由原来的61.53%增加到67.06%,脱水率由原来的92.34%增加到94.86%,降低了循环水浓度,有利于生产的稳定进行。 相似文献