钼酸铵分光光度法测定水中总磷方法的改进

在采用钼酸铵分光光度法测定水中总磷时,分别用恒温干燥箱和国标法消解试样,对测定得到的总磷标准曲线和实际水样中总磷的含量进行了对比。结果表明,恒温干燥箱消解法操作方便、温度易于控制、测定结果准确、可同时处理多份样品、有效的减少工作时间。使用恒温干燥箱代替国标法中的蒸汽消毒器消解样品可行,值得推广。     

钼酸铵分光光度法测定水中总磷的改进研究

应用钼酸铵分光光度法检验水中总磷时,选择消解试样国标法和恒温干燥箱,将检验水样中的实际总磷含量和总磷标准曲线进行对比。结果显示,应用恒温干燥箱进行消解,更容易控制温度,操作更简便,测定结果更准确,而且可以对多份样品进行同时处理,使工作时间得到有效的减少。应用恒温干燥箱替代国标法蒸汽消毒器中的消解样品,方法可行,值得大力推广和应用。     

水中总磷测定消解方法的改进

对GB11893-1989中过硫酸钾水解、钼酸铵分光光度法测定水中总磷方法进行实践和研究,将水样前处理改用恒温干燥箱消解,测定结果符合精密度和准确度要求,操作简便安全,具有一定实用价值。     

封闭微波消解法与高压蒸汽消解法测定总氮对比研究

运用微波密封消解技术测定水样总氮(TN),并与国家标准方法--高压蒸汽消解法相对比.结果表明,该方法不仅节约了消解时间,使碱性过硫酸钾消解彻底,而且节约了试剂,操作简单,准确度和精确度均达到或超过国家标准方法,本实验同时对操作步骤进行了调整和改进.     

同步消解的总磷、总氮测定方法探讨

文章探讨了在同一消解液中同时测定总磷、总氮的分析方法.实验结果表明,选用合适的过硫酸钾的加入量,可在同一消解液中同时测定总磷和总氮,并能克服消解液保存时间短的缺点.应用联合测定方法对标样和水样进行分析,结果准确,方法实用.     

紫外分光光度法测定水中总氮的影响因素探讨

总氮是评价水质环境的非常重要指标,也是反映水体富营养化程度的指标之一。碱性过硫酸钾消解紫外分光光度法是测定水中总氮的国家标准方法,也是目前测定水中总氮最常用的方法。文中针对该测定方法,探讨了总氮测定方法的最佳条件,通过对水样放置时间、消解冷却时间及方式、水样pH、比色前放置时间进行了研究和探讨,以提高测定的准确度和精密度。     

分光光度法测定总铬的氧化加热方式探讨

建立了用饱和氯酸钾溶液做氧化剂,二苯碳酰二肼(DPC)做显色剂测定总铬的方法,并探讨了恒温干燥箱、水浴锅、压力蒸气锅、COD反应器等加热方式对氧化效率的影响。结果表明,恒温干燥箱基本没有氧化效果,水浴锅可得到约50%的氧化率,压力蒸汽锅由于温度及压力不可调控,只能在0. 05⁰. 2 mg/L浓度范围内实现Cr3+的完全氧化,而COD反应器则操作简便,温度可调控,压力随温度变化而变化,在整个实验选择的总铬浓度范围内均取得了较好的氧化效果。     

无汞、无银国标COD测定法的改进

改进了国标COD的测定方法。取水样10.00 mL,加人10.0 mL K2Cr2O7标准溶液、10.0 mL浓H2SO4、2.0mL浓H3PO4和0.1 g MnSO4,以代替Ag2SO4作催化剂和HgSO4作Cl-的掩蔽剂。试样用恒温电热干燥箱加热至190℃,维持18~42 min(视水样中污染物的含量及性质而定)。将实验得到的COD值与国标法测得的COD值相比较,准确度和精密度全都在允许范围内。筛选了对高、中、低浓度COD消解的最佳时间和温度,为COD无汞、无银快速测定提供了实验依据。     

卤素水分测定仪检测端羟基聚二甲基硅氧烷挥发分含量的方法研究

通过对电热恒温鼓风干燥箱测定的端羟基聚二甲基硅氧烷挥发分含量检测结果的参考,论述了用卤素水分测定仪检测端羟基聚二甲基硅氧烷挥发分含量的可行性,同时推导出得到对应结果所需的时间,并进行了验证。结果表明:采用传统的电热恒温鼓风干燥箱加热法测定端羟基聚二甲基硅氧烷挥发分含量耗时长,而卤素水分测定仪由内置的卤素干燥单元加热,升温速度快且均匀,重复性好。检测过程中,从称量到加热一步完成。用卤素水分测定仪测定端羟基聚二甲基硅氧烷挥发分含量可极大地提高检测效率,很好地满足生产检测及质量控制的需要,两种方法测定结果的相对误差小于5%。     

紫外法测定地表水中总氮的影响因素探讨

结合碱性过硫酸钾消解紫外分光光度法水质总氮测定过程中总氮空白值偏高的问题,从实验用水的选择、过硫酸钾试剂的选择和配制储存以及消解过程的问题等方面探讨了其影响因素以及优化建议。对浑浊水样探讨了不同处理方法包括絮凝沉淀法、离心后消解法、0.45μm滤膜过滤后消解法、消解后离心法和消解后0.45μm滤膜过滤法等分别对其总氮结果的准确性影响,通过比对分析得出消解后离心分离法和消解后0.45μm滤膜过滤法都能快速有效地去除浊度干扰,提高总氮测定的准确度。     

Moisture equilibrium of wood and bark chips in superheated steam

This study relating to the steam drying of biofuels suggests that the activities of water in air (defined as relative humidity) and of water in superheated steam (defined as the ratio of the saturated pressure and the saturated pressure at the superheated temperature) are identical. The dependence of the activity in superheated steam on the equilibrium moisture content was studied in various experiments for different wood materials at constant temperatures of 140 and 160°C. The equilibrium moisture content was found to depend on the following factors: the activity of the superheated steam, the temperature and the materials used, the first of these being the most important. The experimentally determined sorption isotherms were compared with different sorption theories. The Dent model gave a good correlation with the experimental data. The sorbed water can be divided into primary water with high binding energy and secondary water with low binding energy. If biofuels are to be dried with superheated steam, an equilibrium moisture fraction of 0.05 seems to be relevant. It will probably be possible to reach this with activities in the range 0.2–0.4 for all real materials.     

CFD Investigation of Non‐Condensable Gases in Vacuum and Non‐Vacuum Steam Sterilizers

Steam sterilization processes rely on high heat transfer rates from the steam to the medical devices. To guarantee this, all non‐condensable gases (NCGs) must be removed from the steam sterilizer before sterilization. The ratios and distribution of the NCGs in the pre‐sterilization phases of both a vacuum and a non‐vacuum steam sterilizer are investigated. Two CFD models for simulation of the NCGs in the sterilizers were developed and validated by the measurements of a pressure sensor and eight thermocouples inside the steam sterilizer. Furthermore, a novel method was developed to calculate the real ratio of NCGs based on the standard measurement (EN 13060). The results show that the NCGs ratio defined in the EN 13060 did not accurately represent the real ratios of the NCGs.     

F-T合成反应器汽包换热系统动态响应研究

建立了1个考虑自蒸发作用的汽包动态模型,引入自蒸发速度计算公式,将该汽包模型作为费托合成反应器的换热系统在Aspen Dynamics中进行动态模拟。考察了当存在反应器入口液相温度变化、反应器设定温度变化及新鲜气流量变化等扰动时系统的动态响应。结果表明使用"Flash"汽包模型对反应器温度波动的计算结果要比使用自蒸发汽包模型时偏小;与用固定温度冷却水移热相比,使用汽包换热更加有利于对反应器温度的控制。水蒸发压力差变化的补偿作用使得汽包蒸发面积对汽包自蒸发速率的影响很小。随着汽包-换热管体系中水体积以及水蒸气体积的增加,反应器温度的最大波动值变大;但随着传热温差的减小,水蒸气的体积变化对温度波动的作用减弱。     

The cause of the uneven carbonization process in wet coal charging in coke oven chamber

In the case of the wet coal charging process in coke oven chamber, it is known that the coking process is uneven and a local carbonization delay occurs. The reason was investigated through a laboratory-scale experiment and a quantitative estimation. A partial carbonization test in a test coke oven replicated the uneven plastic layer and local carbonization delay. It was revealed that most of the gas generated in the uncarbonized coal layer results from the evaporation of condensed water and that steam can break through the plastic layer in a test coke oven. Moreover, the order estimation implied that steam that generates in the uncarbonized coal layer and breaks through the plastic layer has sufficient heat capacity to cool the heating wall and delay the carbonization. It was also shown that the steam pressure peak measured in a commercial coke oven is much lower than the estimated steam pressure in this study assuming steam not breaking through the plastic layer. The above-mentioned results and quantitative investigation strongly support the ‘steam breaking through the plastic layer’ theory proposed by Dr. Rohde that an uneven carbonization process is caused by vaporized coal moisture breaking through the plastic layer at definite, unforeseeable points, which results in cooling of the wall by the steam flow.     

应用智能控制技术优化轮胎硫化控制系统

采用中控PLC，智能温控器及压力仪表等替代原三针记录仪，实现轮胎硫化外温的闭环控制和记录，利用电动机变频调速技术，使硫化用水的压力恒定，并取消一次水供水泵，降低电能消耗，取消硫化机冷凝水排放的疏水阀，实现由温度和定时控制相结合的冷凝水自动排放方式，节约蒸汽用量，在硫化机上加装轮胎胎号输入装置，使轮胎硫化过程参数的历史查询更为方便。     

RK-05低压甲醇催化剂在焦炉气制甲醇中的应用

介绍了RK-05型低压甲醇催化剂在焦炉气制甲醇装置上的升温还原及使用情况。结果显示,该催化剂在低温区(210℃～225℃)表现出较好的催化活性;在催化剂进入稳定期后,甲醇产量稳定,总碳平均利用率为95.5%,粗醇中副产物乙醇质量分数小于230×10-6。     

Steam stripping of lard

Conclusion The rate of steam stripping of free fatty acids from lard can be evaluated in terms of a rate·constant K defined by Equations 5 and 6. Reproducible results were realized for many different batches of leaf and prime steam lards. The effects of temperature, total pressure, and steam rate were evaluated, thus making possible the calculation of stripping rate constants on a comparable basis. Comparable values of the rate constant K have been compared for conditions with and without the use of mechanical agitation with a flat-blade mixing impeller. Use of the rotating mixing impeller showed substantial increases (30 to 50%) in the reaction rate constant, over those obtained with steam sparging without the mixer. Accordingly the use of this type mixer should result, in large savings of steam for stripping and for maintaining the necessary vacuum by the steam jet condenser. Presented at the 1952 Spring Meeting, American Oil Chemists' Society, Houston, Tex., Apr. 28–30.     

轮胎硫化介质的比较

通过查阅国内外有关轮胎硫化方面的文献，就过热水硫化、蒸汽硫化和蒸汽／氮气硫化介质的现状及其在实际应用中的情况进行了分析，并比较了各种硫化介质的优劣之处。     

电捕焦油器的连续运行措施

针对电捕焦油器多次停工原因,对现有的装备、操作进行了改进,通过改造氧分析仪附件、整流装置,增设氨水冲洗装置,控制工艺指标,实现了电捕焦油器的连续运行,得出了电捕焦油器正常连续运行的基本条件:保证蒸汽压力0.4MPa±0.1MPa,保证集气管压力波动在80Pa±20Pa,氧分析仪零位气体采用标准氮气,冷却样气用水采用除盐水,整流装置采用恒流高压直流电源,增设氨水清扫装置,增设备用电捕焦油器。