己内酰胺浓缩工艺初探

文章通过对己内酰胺精制装置改扩建项目的对比分析,探讨改用“环己酮氨肟化技术”后,己内酰胺浓缩部分采用新工艺去杂的可能性,提出适合新技术条件下的己内酰胺浓缩工艺,并运用流程模拟软件“ASPEN”对新老工艺进行模拟计算,分析新工艺去除杂质的可行性。     

Chemical and Isotopic Tracer Evaluation of Water Mixing and Evaporation in a Dammed Texas River During Drought

The interaction between drought and river regulation is monitored to better understand river flow mixing, evaporation and surface‐groundwater exchange in changing regional climates and in increasingly regulated waterways. This study compared Brazos River stable isotope (δ¹⁸O and δD) and electrical conductivity values with reservoir, creek and aquifer samples in the Brazos watershed, the largest watershed in Texas. The combination of tributaries, rainfall and the Brazos River Alluvium Aquifer, on the one hand, and the Lake Whitney reservoir, on the other hand, represent endmembers of dilute run‐off water and evaporated saline water, respectively. A simple isotope mixing model that uses monthly river discharge, Lake Whitney discharge, historical monthly precipitation δ¹⁸O and pan evaporation accurately reconstructs river δ¹⁸O (±0.5‰ on average). Data and isotope balance modelling support continued evaporation of ¹⁸O‐enriched Lake Whitney water as it flows downstream, although the most evaporation took place in Lake Whitney. The difference between river and precipitation δ¹⁸O, or Δ¹⁸O_RIV‐_PPT, here a measurement of degree of evaporation, ranged from ?0.1‰ for a small creek, to 1.7‰ for the Brazos River, to at least 2.7‰ in Lake Whitney. This study indicates that drought in regulated rivers may enhance reservoir discharge dominance in river flows during peak drought conditions when combined run‐off and baseflow dominance would be expected in a similar undammed river. Copyright © 2016 John Wiley & Sons, Ltd.     

磁性浮板覆盖下干旱区平原水库节水效率分析

针对干旱区平原水库水深浅、风速大、气温高、空气相对湿度低而导致蒸发损失严重的问题,在吐鲁番市胜金乡胜金沟三期水土保持水库进行了一整年不同覆盖面积的带磁性浮板与非磁性浮板覆盖水面来减少水面蒸发的试验,以此来分析相同覆盖面积下带磁性浮板成片整体分布与非磁性浮板分散分布对水库水面蒸发的节水效率。试验结果表明：在气象因素相同的情况下,带磁性浮板分别覆盖水面25％,50％和75％时,蒸发抑制率分别为27.4％,41.5％和59.1％;非磁性浮板分别覆盖水面25％,50％和75％时,蒸发抑制率分别为22.1％,38.1％和57.3％;带磁性浮板比非磁性浮板蒸发抑制率分别提高了5.3％,3.4％和1.8％。可见,带磁性浮板节水效果更加显著,对提高干旱区平原水库水资源的利用效率具有显著意义。     

岱海湖温排水对湖面附加蒸发量影响研究

岱海湖为一内陆封闭型湖泊。本研究利用3、7、12月份冬夏工况,综合考虑岱海湖边界条件,水面温度、密度、水面天然温度、大气温度、相对湿度等影响因子,构建温排水对岱海湖附加蒸发量影响的计算公式。经计算,电厂温排水引起的岱海湖附加蒸发损失量为:3月份为39.46万m3,7月份为73.3万m3,12月份为10.6万m3,岱海湖电厂温排水年附加蒸发水量约为678.2万m3/a。结果表明:附加蒸发量与电厂温排水量变化一致。本研究对干旱区水资源利用具有重要意义。     

钠基膨润土防水毯在滹沱河防洪整治中的试验研究

结合滹沱河防洪综合整治工程,对钠基膨润土防水毯建立试验模型,着重研究不同试验水头、外界环境条件(温度、风力等因素)对钠基膨润土防水毯的渗水量、水分蒸发量和渗透系数的变化规律。研究结果表明:试验水头与渗透系数成非线性关系,且渗水量随水位的增加而增加,渗透系数随水位的增加而减小。通过模型试验验证了钠基膨润土防水毯高密实、高防水等特点,为类似的防洪综合整治工程提供了技术支撑。     

空气阻力系数对水滴运动及蒸发的影响

应用喷灌条件下水滴的运动、蒸发及分布模型对水滴的飞行时间、飞行距离以及蒸发率进行了预测,并对5种空气阻力系数计算公式 （Bird、Park、Fukui、伊沙叶夫、Wallis） 求得的预测值和实测值进行了比较。结果表明：应用Bird、Wallis、Fukui公式预测的水滴飞行时间与实测值随水滴直径的变化趋势一致,应用Park和伊沙叶夫公式求得的水滴飞行时间预测值与实测值的相对误差最小;5种阻力系数公式均能较准确地预测水滴飞行距离,其中Park公式的预测精度最高;5种阻力系数公式对于单个水滴蒸发率的预测结果与实测值之间的平均相对误差在26.1%~30.2%之间;5种阻力系数公式对总蒸发率的预测影响不明显,预测值与实测值之间的平均相对误差在15.2%~17.5%之间。建议在水滴运动和蒸发计算中采用Park阻力系数公式。     

黄河巴彦高勒蒸发实验站水面蒸发模型的建立

采用分段风速函数建立了黄河巴彦高勒蒸发实验站的道尔顿水面蒸发模型,计算结果表明:当风速小于3 m/s时,模型计算蒸发量与实测蒸发量相关关系很好,可基本消除水面蒸发经验公式在不同风速段出现不同系统性误差的现象;风速大于3 m/s时,模型计算结果不太理想。     

ZFZ-01数字式水面蒸发自动站在南宁水文站的应用

介绍了数字式水面蒸发自动站的工作原理,通过与常规E601B型蒸发器同步比测实验,实现了蒸发观测在线监测.蒸发观测自动化、信息化,为防灾减灾决策提供及时、准确的科学依据.     

水面蒸发模型的进一步优化

水面蒸发量是水文水利计算、径流分析预测及水资源利用评价的主要内容,针对目前水面蒸发计算模型存在的问题,通过对水面蒸发机理的分析,采用最小二乘回归法,建立了由主要影响因子构成的修正系数函数对由相对次要因子构成的主体函数进行修正的基本模型,经比较,该模型具有较好的拟合精度。     

Changes of Pan Evaporation in the Recent 40 Years in the Yellow River Basin

Abstract

Based on monitoring data of 123 meteorological stations from 1960 to 2000 near or in the Yellow River Basin, the spatial and temporal distributions and their trends for pan evaporation (PE) are investigated in this study. The results indicate that, despite the annual mean air temperature over the Yellow River Basin has, on average, increased by 0.6° over the past 40 years, the rate of PE has steadily decreased, especially in summer and spring. Compared with the period of 1960s to 1970s, the rate of annual pan evaporation during 1980s to 1990s has decreased by 126mm or 7.0 percent. Spatial distribution of the rate of change show that this kind of trend is general but not universal, PE has significantly decreased over the upper and lower reaches of the Yellow River, but increased to a small degree over the middle reaches. Further analyses show that the decrease of PE is mainly related to reductions in sunshine durations and solar irradiance, owing to more clouds and aerosols.