纳氏试剂比色法测定污水中氨氮的优化研究

纳氏试剂比色法测定污水中氨氮,其蒸馏预处理过程存在耗时长、馏出液接收不便和操作繁琐等问题.文章对预处理及测定方法进行了优化,提出将水样蒸馏体积减少为50 mL,后期比色体积减少为25 mL,并去除硼酸吸收液,改为直接接收馏出液.经验证,其结果与国标方法无显著性差异,标样验证相对误差为-0.8%~0.9%,实际样品测定结果的相对标准偏差为0.9%~4.4%,加标回收率为94%~107%.优化的方法测量数据稳定,结果准确,在测定污水中氨氮具有实际应用意义.     

含二甲胺工业废水的回收及再利用技术研究

为了消除工业二甲胺废水带来的巨大污染,使其达到回收利用的目的,利用精馏技术,采用BH型高效填料作为分离介质,连续从废水中脱除二甲胺,并将塔顶二甲胺提浓。结果表明,采用本技术可使塔顶二甲胺提浓至47%(质量百分含量),达到满足40%二甲胺水溶液质量要求的目的;塔釜二甲胺含量降低至≤50 mg/L,此水可作皮革工业生产回用水。由于含二甲胺废水经处理后可以全部回收利用,表明该高效精馏技术用于清洁生产中具有可靠性和实用性。     

叠式空气隙膜蒸馏组件膜污染实验研究

采用一种具有旋流结构的多层层叠式空气隙膜蒸馏膜组件,以20 g/L氯化钠盐水为热工质,考察在70℃条件下膜污染情况,实验结果表明,一个周期的连续运行和间歇性操作膜表面在高温下较快进入膜污染,8个周期后膜通量下降为初始通量的42%。膜表面有大量黄色附着物,电镜SEM分析显示,膜表面被不均匀堆积的颗粒状污染物及长方体结晶物覆盖,能谱EDS分析,污染物有极少量NaCl结晶的Na、Cl元素,还有O、C、Mg、Cu和Fe等元素。污染膜经5%盐酸溶液清洗后无机垢沉淀被去除,表观效果较好。     

Simulation Study of a PEM Fuel Cell System with Steam Reforming

Abstract

This article summarizes the results of a study for a 100 kWe DC electrical power PEM fuel cell system. The system consists of a pre-steam reformer, a steam reformer, high and low temperature shift reactors, a preferential oxidation reactor, a PEM fuel cell, a combustor, and an expander. Acceptable net electrical efficiency levels can be achieved via intensive heat integration within the PEM fuel cell system. The calculations take into account the auxiliary equipment such as pumps, com pressors, heaters, coolers, heat exchangers and pipes. The process simulation package “Aspen-HYSYS 3.1’’ has been used. The operation parameters of the reactors have been determined considering all the technical limitations involved. A gasoline type hydrocarbon fuel has been studied as hydrogen rich gas source. Thermal efficiencies have been calculated for all of the major system components for selected operation conditions. The fuel cell stack efficiency has been calculated as a function of cell numbers (500, 750, 1000, and 1250 cells). Efficiencies of all of the major system components along with auxiliary unit efficiencies determine the net electrical efficiency of the PEM fuel cell system. The obtained net electrical efficiency levels are between 34 (500 cells) to 41% (1250 cells).     

混合添加剂对PVDF平板疏水膜结构及性能的影响

以不同添加剂采用浸没沉淀相转换法制备基于无纺布支撑的聚偏氟乙烯(PVDF)平板疏水膜,考察了不同添加剂的加入对膜性能与结构的影响;并利用扫描电子显微镜(SEM)、原子力学显微镜(AFM)、红外光谱(FTIR)、接触角测量及膜蒸馏实验等对疏水膜的结构及性能进行表征。结果表明,引入混合型添加剂制备的膜具有较高通量和盐截留率,其疏水性最强,而添加剂对聚合物的晶型影响较小。以35 g/L的NaCl盐溶液为进料液对制备的平板膜进行直接接触式膜蒸馏实验,在热侧进水温度为50℃、冷侧温度为20℃的条件下,所制备的疏水膜通量最高可达12.45 kg/(m2.h),截留率为99.99%。     

Microwave-assisted stripping of oil contaminated drill cuttings

The application of microwave heating technology to conventional gas stripping processes has been investigated in the remediation of contaminated drill cuttings. The technical feasibility and limitations of nitrogen and steam stripping processes are demonstrated, and it is shown that the combination of microwave heating with the stripping process offers a step change in performance. Order of magnitude improvements in processing time are shown for the microwave-assisted processes, as well as greatly improved levels of remediation. The mechanisms of contaminant removal are discussed, along with the phenomena which occur with microwave heating processes. The energy requirements of each of pure gas and microwave-assisted processes are also discussed, and the potential applications of each technology are highlighted relative to the overall remediation requirements.     

苯甲酸重副产物的脱色处理

为了有效去除苯甲酸重副产物中含有的交联大分子和碳化物等有色杂质，降低有用组分资源化处理的难度，分别采用吸附和蒸馏两种方法对苯甲酸重副产物进行脱色处理。实验结果表明：大孔树脂、硅藻土、活性炭等作脱色剂不能有效去除苯甲酸重副产物中的有色杂质；在真空度0．093～0．095MPa、蒸馏温度220～240℃条件下进行蒸馏脱色，当温度出现回落时停止蒸馏，平均馏出率为66．99％；蒸馏脱色得到的轻组分颜色呈黄色，可满足中和、酸化、结晶、回收苯甲酸的要求；釜残物可作为燃料通过焚烧利用其热能。     

超声处理对提取苦杏仁挥发油的研究

研究了超声处理对提取苦杏仁挥发油的影响。结果表明,超声处理有利于提高苦杏仁挥发油的得率,在所选取的范围内随功率和时间的增加而提高;通过正交实验确定影响挥发油得率的因素从大到小依次为超声功率、物料细度、pH和处理时间,确定最优工艺组合是物料细度为80目;在pH值为5的提取液中浸泡后,超声功率为100W处理30min。经分析,超声处理得到挥发油样品的主要成分是苯甲醛。     

挥发酚的蒸馏损失

回收率实验表明,苯酚经预蒸馏后平均回收率在95%左右,损失率达5%.现提出应用经验系数0.95来修正蒸馏过程带来的损失,结果令人满意.     

DESALTING SALINE WATER FOR IRRIGATION A CASE STUDY,COACHELLA AREA,CALIFORNIA1

ABSTRACT .A case study was performed to evaluate potential applications of desalted saline water for agriculture using 2 distillation type processes and 2 membrane type processes. The investigation determined the costs and benefits associated with desalting saline water at concentrations of 1,500, 900, 400, 200, and 50 ppm. Benefits from desalting are generated by shifts to more profitable crops, reduced costs for drainage, and reduction in fertilizer and labor requirements with better quality water. Costs are based on the project features such as desalting plants, raw water diversion facilities, storage reservoirs, conveyance and distribution systems, brine disposal, blending facilities, and gypsum addition systems. Hydrologic studies determined the crop irrigation requirements, water demand schedules, desalted water storage requirements, brine disposal requirements, and size of facilities required. Reconnaissance design layouts were made for producing desalted water using a combination of 14 schemes. The study also included a review of irrigation practices. The benefit-cost ratios range from 0.4 to 1.0 for 1,500 ppm irrigation water to 0.8 to 1.0 for 50 and 200 ppm water. Investment costs per acre are high, ranging from $12,900 to $20,900. Irrigation benefits are based on the increase in production from a desert condition with no water supply to the irrigation conditions studied.