高掺粉煤灰、煤矸石节能空心砖参数优化研究

采用实验方法对不同配比、不同粒径、不同干燥时间、不同烧结温度下成砖硬度、表面光洁度、烧结损坏率等指标进行多组平行实验,研究高掺粉煤灰、煤矸石节能空心砖的最优工艺参数。研究结果显示,粉煤灰、煤矸石烧结空心砖的最佳配方组成为煤矸石50%、粉煤灰50%;原料细度范围在1~2 mm占15%,其余小于1 mm即可;最佳干燥条件为干燥介质的温度范围120~150℃,流速1.5~4.5 m/s,干燥周期12~48 h;最佳烧成温度1 050℃,烧成周期47~52 h,保温4~8 h。     

低温干化床污泥干化特性及优化方案

由于污泥热干化所需能耗较高,而传统的太阳能干化周期较长,采用集热式太阳能干化能够有效降低干化成本,提高干化效率。为了获得该方式下低温干化床污泥干燥特性,设计了模拟实验装置,分析了在不同污泥层厚度、翻泥频率、干化床温度等条件下污泥干化床的表现。实验结果表明,干化床单位面积的干燥能力随着污泥层厚度的增加而减少,污泥层的最佳厚度为10 cm;在干化过程中,翻泥能够促进污泥内部水分的扩散与蒸发,为节约翻泥能耗,以12 h的翻泥间隔为最优;温度对污泥干化速率的影响明显,水温70℃时其干化速率明显高于50℃、60℃时,但是需要较多额外辅助能源,为充分利用太阳能,适宜采用60℃作为干化床温度。     

响应面法优化西兰花总黄酮提取工艺的研究

利用响应面法优化西兰花总黄酮的提取工艺条件。在预试验的基础上,以乙醇为溶剂,提取西兰花总黄酮。选取提取温度、提取时间及液固比、乙醇浓度4个因素进行Box-Benhnken中心组合设计,利用响应面分析法对提取工艺参数进行优化。结果表明,西兰花总黄酮的提取工艺为:乙醇浓度90%,液固比30∶1,提取温度85.28℃,提取时间1.82h;预测值为0.887%,实际得率为0.853%,两者较接近,说明Box-Behnken设计结合响应面分析法可很好地对西兰花总黄酮提取工艺进行优化。     

油基岩屑热脱附工程实验能耗分析与优化

热脱附技术被鼓励用于油基岩屑资源化处置,针对其工程应用中能耗相对偏高的问题开展研究, 采用两段螺旋推进式间接热脱附工程实验平台,设定天然气燃烧产生的热量与热脱附装置各环节消耗热量之和相等,据此进行平衡计算和能耗分析,基于响应曲面法对油基岩屑热脱附过程中的4个因素和两个目标进行 优化实验并加以验证。结果表明,水分蒸发吸收的热量和残渣余热之和约占总热量消耗的2/3;当油基岩屑中的含水率和含油率分别每增加1％,天然气消耗量将分别增加2.53Nm3和1.81Nm3;运用优化实验方法,可使 实验装置运行总能耗降低6.01％～13.16％。综上,通过采取降低油基岩屑含水率、含油率及优化运行参数等措施,可以显著降低热脱附装置的能耗,采用热量衡算和热脱附参数优化方法,可以为工业化油基岩屑热脱附节能降耗提供参考。     

蚯蚓生物处理污泥系统动力学研究及探讨

通过对处理周期前后污泥、蚯蚓重量,以及有机碳等指标的测定,对污泥处理系统进行了物料衡算;生活污泥经蚯蚓处理后,干重降低了28%,有效的实现了减量化,有机物质总量削减了57.14%,稳定化、无害化效果显著。同时结合蚯蚓生物处理污泥系统原理,基于冬季有机碳等指标的检测数据,确定本系统的动力学反应级数为一级,并在此基础上,建立了动力学模型与反应器模型。     

蜈蚣草总黄酮提取工艺的优选

采用水浴法提取总黄酮,以蜈蚣草为原料、总黄酮得率为考察指标,通过正交试验研究乙醇浓度、提取时间、提取温度及料液比对提取蜈蚣草总黄酮得率的影响。结果表明,各因素对总黄酮提取率的影响程度为∶乙醇浓度提取时间提取温度料液比;最佳的提取工艺条件为:乙醇浓度60%,料液比1∶15,提取温度60℃,每次3h,提取3次,在此条件下提取的总黄酮得率为6.15%。     

燃煤锅炉的烟尘排放情况的物料衡算法研究

燃煤锅炉产生的烟尘量与燃料的成分、锅炉的燃烧方式及除尘率有直接的关系,锅炉的燃烧方式分为层式燃烧和悬浮式燃烧,不同燃烧方式的产尘量有很大区别,通过物料衡算方法,尝试对使用不同燃烧方式的工业锅炉和电厂锅炉排放的烟尘量进行定量分析和计算,该法得到的数据较准确,一般接近监测得到的平均数据.     

新疆油田高含盐稠油污水蒸发除盐试验研究

为实现新疆油田高含盐稠油污水资源化利用,减少稠油热采开发过程中的高含盐稠油污水排放量及清水资源消耗量,根据该油田污水水质高矿化度、高盐的特点,提出了机械蒸汽压缩MVC污水蒸发除盐回用处理技术。针对燃煤注汽锅炉排放的高含盐稠油污水开展了机械蒸汽压缩蒸发除盐的现场先导试验,阐述了机械蒸汽压缩的主体工艺流程、工艺技术特点、进出水水质、运行成本、产水率、结垢情况以及试验中存在的问题及改进措施。结果表明,该技术水回收率≥90%,出水矿化度50mg/L,实现了污水的资源化利用。最后针对该工艺应用现状及存在的高投资、高成本等问题,提出相应建议。     

草面温度的变化特征及影响因素分析

利用2013年6月~2014年11月青海15个站草面温度观测资料,运用气候统计诊断方法对青海省草面温度的变化特征、草面温度与气象要素的关系等进行了分析。结果表明,草面温度呈一峰一谷的日变化特征,全省草面温度日最低值出现在6时,日最高草面温度出现在14时,说明太阳辐射是影响草面温度日变化的主要因素。月平均最低值出现在12月,为-10.6℃,月平均最高值为18.1℃,出现在7月;各站草面温度的月变化趋势基本一致,最大变温均出现在11月;草面温度的季节变化均表现为夏季春季秋季冬季的气候特征;青海省草面温度变化呈东部高西部低、北部高南部低的特点,说明草面温度的高低受纬度、拔海高度和地理环境的影响比较明显。15个站草面温度与气温、地温均呈显著的正相关,与总云量、低云量呈显著的反相关,全部通过了0.05以上显著性检验水平。无论是晴天、阴天还是多云天,草面温度的日变化均为不光滑的曲线,但不同天空状况下草面温度的日变化趋势基本一致。     

高含盐采出水冷冻脱盐技术研究

由于高含盐采出水中氯离子浓度和矿化度很高,为了实现油田高含盐采出水的回注,除了降低石油类、COD和SS的含量外,还要去除其中大量的无机盐类。文章研究了对某油田高含盐采出水采用冷冻脱盐技术的处理效果,通过对模拟水和实际采出水进行脱盐实验,对影响冷冻速率的因素,冷冻脱盐效率和重力脱盐效率进行了研究。冷冻脱盐法直接脱盐率为50%以上,通过进一步静置,最终的脱盐率可达到60%以上。较高的初始温度、缩短水从液态冷冻到固态的时间、延长重力脱盐时间,能获得更好的脱盐效果。     

ESTIMATION OF ENERGY REQUIREMENTS OF MORNING DEW EVAPORATION FROM LEAF SURFACES1

ABSTRACT: Evapotranspiration from vegetation is generally computed without consideration for early morning energy loss involved in drying wet leaf surfaces. In humid areas where dew formation is frequent, estimation of energy requirements for evaporating dew should be of interest. In this study, sensible heat flux (H) was computed from wind and temperature profile measurements over the study site. A leaf wetness sensor was used to measure the duration of evaporation from an exposed leaf surface, and net radiation was measured with a radiometer. The energy flux during the period of wet leaf surface evaporation was integrated over time. A cattail lysimeter situated at the site indicated the time when evapotranspiration started after wet leaves were dry. The energy requirements to dry an exposed wet leaf surface was estimated using energy balance methods. The mean value based on 44 days of observations from mid February to early May of 1993 indicates that the energy required to evaporate dew from openly exposed wet leaves was 5 percent of the total daily evapotranspiration of cattails with a coefficient of variation of 0.72. The mean time required to evaporate dew from exposed leaf surfaces from the onset of positive net radiation was 78 minutes. The mean dew evaporation in a morning from an exposed leaf surface was 0.16 mm with a maximum value of 0.41 mm. The energy required to dry wet leaves is a factor that should be considered when modeling evapotranspiration at hourly or shorter time intervals. Also, physical evapotranspiration models need to account for energy requirements for drying dew and rainfall wetted leaves.     

Refrigeration waste heat utilization for drying applications: a review

ABSTRACT

Cold chain industry has a vast potential for waste heat recovery. It is a matter of importance for energy efficiency point of view, as global energy demand is increasing day by day. Ample amount of low-grade energy is either unutilized or underutilized. The heat rejected by a Heat pump or refrigeration system emerged as a promising solution for dehydration by utilizing low-grade waste heat despite higher investment. As compared to solar drying technology, heat pump drying evolved as a reliable method regarding better process control, energy efficiency, and quality of the product to be dried. Energy utilized through the refrigeration system’s waste/exhaust heat recovery in combination with or without renewable energy source enhances the overall efficiency of the system and also reduces the cost. This useful review investigated and compared the research findings of waste heat utilization through heat pump and from condenser of refrigeration system on laboratory, pilot as well as industrial scale for drying of various fruits, vegetables, and agro products. Various drying parameters like drying rate, moisture content, Specific Moisture Extraction Rate (SMER), Coefficient of Performance (COP), Exergy efficiency, and temperature as well as humidity conditions inside the drying chamber were also reviewed to promote the technological advancement of energy utilization by commercial cold storage waste heat recovery.     

水平-竖直管降膜多效蒸发高盐废水处理系统

为克服现有的高盐废水多效蒸发能耗高的问题,提出了水平-竖直管降膜多效蒸发高盐废水处理系统。工艺流程的原理分析和工程实例计算证明,利用竖管降膜蒸发器生成的二次蒸汽作为水平管降膜多效蒸发系统的加热蒸汽,使废水在水平管降膜蒸发器内浓缩,可大幅度降低在竖管降膜蒸发系统内进行蒸发结晶的废水量,从而减少废水蒸发消耗的高温高压蒸汽量,因此该技术是具有发展前景的高盐废水处理节能新技术。     

A numerical model for drying of spherical object in an indirect type solar dryer and estimating the drying time at different moisture level and air temperature

A numerical model for simultaneous heat and mass transfer was developed for solar drying of spherical objects and the object considered is green peas. Solar collector outlet temperature is assumed as drying chamber temperature and justified through energy balance equations. Assumptions are imposed on heat and mass transfer governing equations without losing the physics of the problem. Discretization is performed by finite difference method with implicit scheme. To generalize, the governing equation and boundary conditions are non-dimensionalized. The set of finite difference equations was solved by Tridiagonal Matrix Algorithm and a computer code in MATLAB was developed to solve them. The drying curves showed two stages of drying, initial, and secondary drying stage. At all drying temperatures and drying time, the center moisture was maximum and it was minimum at the boundary. A percentage of 85.67 surface moisture content and 25.33% center moisture was eliminated in the first 1 hr at 348 K. The product should be dried up to 7.45, 4.74, and 3.74 hr at air drying temperatures of 318, 333, and 348 K respectively, to maintain 10% of the product’s initial moisture content. The result is compared with the experimental result from literature and they are found to be in good agreement.     

EFFECT OF TWO IMPOUNDMENTS ON THE SALINITY AND QUANTITY OF STORED WATERS1

ABSTRACT The effect of hydrologic and chemical processes on salinization of stored waters was determined for two small floodwater-retarding structures located in western Oklahoma. One structure, already designed to accommodate a large influx of sediment, was further overdesigned hydrologically by upstream diversion of approximately one-half the inflow. Over a 2-year period, the total salinity of stored waters increased approximately 22 times and the stored water volume decreased to 1/33 its initial volume in the overdesigned structure, while both volume and salinity of stored waters remained comparatively stable in the other structure. The lack of sufficient dilution by better quality surface runoff and the increased residence time of water in the impoundment apparently caused most of the salinity increase. The bulk of the salt load entering the over-designed structure, to be concentrated later by evaporation, was associated with base rather than storm inflow. After base inflow ceased, substantial losses of salt load and stored water occurred concurrently. The loss was not adequately explained by chemical precipitation in association with evaporation. Seepage and evaporation-associated variables appeared to account for much of the hydrologically unexplained loss of stored waters.     

AN AUTOMATED RECORDING SYSTEM FOR EVAPORATION PANS1

ABSTRACT: ABSTRACT: An automated recording system for evaporation pans was developed to allow continuous analog type recording of pan evaporation. The system incorporates a water reservoir to supply water to the pan and can be left unattended for long periods of time. The system performed well, with very little maintenance, in a field test in northern Utah.     

含铀TBP/OK废液相分离技术研究

为探究含铀TBP/OK废液高效低成本处理技术,采用磷酸加合水解法开展TBP/OK废液相分离技术研究,得出加合反应及加合物水解反应最佳条件试验参数。结果表明,采用磷酸加合水解法将煤油和TBP依次从TBP/OK废液中分离出来,能大幅降低放射性废液体积,分离后煤油和TBP实现分类处理能有效降低放射性废液处理难度。     

AN INSULATED EVAPORIMETER1

Evaporation was measured from a circular evaporation pan, 18 inches in diameter and 8 inches deep. The pan was insulated on the sides and bottom using 2 inches of freon-blown polyurethane foam. A U.S. Weather Bureau Class A evaporation pan was used to obtain reference evaporation measurements. Water evaporation from the Class A pan and the insulated pan were highly correlated. Using a water-methanol mixture, the insulated pan may be operated at temperatures below 32 F; the equivalent liquid water evaporation may be determined using a regression equation.     

DEFINING WATERSHED-SCALE EVAPORATION USING A NORMALIZED DIFFERENCE VEGETATION INDEX1

Monthly composites of the Normalized Difference Vegetation Indices (NDVI), derived from the National Oceanic and Atmospheric Administration's (NOAA) Advanced Very High Resolution Radiometer (AVILRR), were transformed linearly into monthly evaporation rates and compared with detailed hydrologic-model simulation results for five watersheds across the United States. Model-simulated monthly evaporation values showed high correlations (mean R²= .77) with NDVI-derived evaporation estimates. These latter estimates, used in a classical water balance model, resulted in equally accurate simulations of monthly runoff than when the model was run to estimate monthly evaporation via soil moisture accounting. Comparison of NDVI-derived evaporation estimates with pan data showed promise for transforming NDVI values into evaporation estimates under both wet and water-limiting conditions without resorting to the application of any kind of calibrated hydrologic models.     

市政污泥干化焚烧工艺设计与思考

以南方经济发达地区100 tDS/d的污泥干化焚烧发电工程为例,介绍了污泥处置的热电联用系统.工程利用离心干化设备,以废蒸汽为热源干化污泥,提高热值,干化污泥与生物质在循环流化床锅炉中协同焚烧,焚烧产生的蒸汽通过汽轮发电机组发电自用.烟气经过多级处理后达标排放,废水、飞灰和炉渣都得到有效的处理与处置.该工程的实施缓解了...