500kV HGIS(GIS)变电站噪声测试及特性分析

通过对典型设计的500kV HGIS(GIS)变电站主要设备和厂界噪声进行测试,分析了厂界噪声的排放控制因素和变压器噪声传播衰减特性,为500kV HGIS(GIS)变电站的设计和噪声防治提供参考.     

高压变电站对周围环境的影响与评价

从大量的实际监测数据出发，评述了高压变电站内部和外部环境的电磁场分布情况，并就变电站对周围环境的影响水平进行了分析和评价。     

兰州市区地下电力电缆对环境的电磁影响分析

在参照架空输电线路电磁环境特性及其影响因子的基础上,分析预测了地下电力电缆对电磁环境的影响,识别和筛选了地下电力电缆的环境影响因子,并对兰州市区三条典型地下电力电缆的电磁环境进行实测,验证其对环境的影响,分析电缆在地下及地面上磁场衰减规律,最后得出其周围会产生一定的工频磁场,但远小于现有标准中的公众暴露限值,同时,也不会对所提出的敏感对象产生干扰。     

建设项目卫生防护距离的确定方法

建设项目环境影响评价过程中的选址问题至关重要,卫生防护距离的可达性是必不可少的因素.以合成氨厂为例,探讨环境影响评价中卫生防护距离的确定方法,对无组织排放源、源强及参数的确定进行了说明.     

设置变电站电磁环境影响防护控制区的必要性探讨

通过对几种典型变电站及其进、出线电磁环境实测数据的分析,认为变电站站外不需划定电磁环境影响防护控制区.     

炼油污水处理装置恶臭气体源强估算方法的比较

以某炼油污水处理装置为例,根据其运行现状及恶臭气体的监测结果,使用卫生防护距离反推法、源强经验估算法以及地面浓度反推法3种方法对恶臭气体源强进行估算,并利用AERMOD模式进行预测,对预测值与监测值进行方差分析。实验结果表明：在监测得到的NH₃和H₂S的平均质量浓度分别为0.113,0.006 mg/m³的条件下,卫生防护距离反推法得到的NH₃和H₂S的无组织排放源强分别为2.395,0.127 kg/h。源强经验估算法得到的NH₃和H₂S的源强分别为0.255,0.080 kg/h,地面浓度反推法得到的NH₃和H₂S的源强分别为3.120,0.250 kg/h;源强经验估算法为炼油污水处理装置气体源强估算的最优方法。     

500kV变电站噪声影响及防治措施

通过对典型的500kV变电站主要声源和厂界噪声监测,分析说明降低变电站噪声影响应采取的防治措施,为500 kV变电站设计和噪声防治提供参考。     

居民区地下配电房通风降噪仿真与分析

为了合理控制居民区地下配电房的室内温度,降低机械通风带来的环境噪声,建立了配电房风速场的仿真模型并对其进行分析计算。以佛山鸿翔小区一个位于某住宅楼地下的配电房为例,使用ANSYS13.0软件对其中主要热源———变压器周围的风速场进行仿真分析。结果表明：在保证室内电气设备工作温度的前提下,优化计算通风量,通过电缆沟辅助进行机械排风,使电房噪声由之前的平均79dB( A)降低到71dB( A)。通过修改模型中的相关参数,可用于其它地下配电房温度场的模拟与预测,为设计提供前期参考。     

油浸式电力变压器的噪声源及降噪对策

介绍了油浸式电力变压器噪声污染现象和噪声源,从理论上分析了噪声源及其噪声计算方法,指出了在实践中从设计方面降低噪声的具体方法以及进行变压器结构改进来抑制振动传播的工艺措施.     

变电站电磁环境管理现状概述

主要论述了当前我国变电站电磁环境管理方面的现状,包括政策法规、标准规范以及当前的电磁环境监测方法,并探讨了变电站电磁环境管理中存在的诸多问题与不足。在此基础上提出了电磁环境管理的相关措施和对策建议,包括完善法规、标准体系、加强监管体系建设、细化公众参与和加强电磁环境的科普宣传以及探索新的电磁环境监测方法。最后,重点介绍了变电站电磁环境在线监测管理的方法。     

Hydration and leaching characteristics of cement pastes made from electroplating sludge

The purpose of this study was to investigate the hydration and leaching characteristics of the pastes of belite-rich cements made from electroplating sludge. The compressive strength of the pastes cured for 1, 3, 7, 28, and 90 days was determined, and the condensation of silicate anions in hydrates was examined with the ²⁹Si nuclear magnetic resonance (NMR) technology. The leachabilities of the electroplating sludge and the hardened pastes were studied with the multiple toxicity characteristic leaching procedure (MTCLP) and the tank leaching test (NEN 7345), respectively. The results showed that the electroplating sludge continued to leach heavy metals, including nickel, copper, and zinc, and posed a serious threat to the environment. The belite-rich cement made from the electroplating sludge was abundant in hydraulic β-dicalcium silicate, and it performed well with regard to compressive-strength development when properly blended with ordinary Portland cements. The blended cement containing up to 40% the belite-rich cement can still satisfy the compressive-strength requirements of ASTM standards, and the pastes cured for 90 days had comparable compressive strength to an ordinary Portland cement paste. It was also found that the later hydration reaction of the blended cements was relatively more active, and high fractions of belite-rich cement increased the chain length of silicate hydrates. In addition, by converting the sludge into belite-rich cements, the heavy metals became stable in the hardened cement pastes. This study thus indicates a viable alternative approach to dealing with heavy metal bearing wastes, and the resulting products show good compressive strength and heavy-metal stability.     

The hydration characteristics and utilization of slag obtained by the vitrification of MSWI fly ash

This study investigated the effects of slag composition on the hydration characteristics of slag blended cement (SBC) pastes. Synthetic slag samples were prepared by melting CaO-modified and Al(2)O(3)-modified municipal solid waste incinerator (MSWI) fly ash. MSWI fly ash was mixed with 5% CaO and 5% Al(2)O(3) (by weight), respectively, resulting in two fly ash mixtures. These mixtures were then melted at 1400 degrees C for 30 min to produce two types of slag with different contents, designated at C-slag and A-slag. Both the C-slag and A-slag samples exhibited a pozzolanic activity index higher than the unmodified slag sample. The results show that the synthetic slags all met the Taiwan EPA's current regulatory thresholds. These synthetic slags were then blended with ordinary Portland cement (OPC) at various weight ratios ranging from 10 to 40%. The 28-day strength of the C1 paste was higher than that developed by the OPC paste, suggesting that the C-slag contributed to the earlier strength of the SBC pastes. At curing times beyond 28 days, the strength of the A1 paste samples approached that of the OPC paste samples. It can be seen from this that increasing the amount of calcium and aluminum oxide increases the early strength of SBC. The C-slag blended cement paste samples showed an increase in the number of fine pores with the curing time, showing that the C-slag enhanced the pozzolanic reactions, filling the pores. Also, the incorporation of a 10% addition of C-slag also tended to enhance the degree of hydration of the SBC pastes during the early ages (3-28 days). However, at later ages, no significant difference in degree of hydration between the OPC pastes and the SBC pastes was observed with the 10% C-slag addition. However, the incorporation of A-slag did decreased the degree of hydration. A slag blend ratio of 40% significantly decreased the hydration degree.     

Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test

Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane.     

The adsorption characteristics of heavy metals by various particle sizes of MSWI bottom ash

The incineration rate of municipal solid waste (MSW) has been increased because of difficulty in securing a proper disposal site for MSW in Korea. The advantage of incineration is reduction of the volume of waste; however, significant amounts of bottom ash and fly ash were generated in the incineration process. Their treatment has attracted growing interest because of the potential toxicity of hazardous heavy metals. Generally, heavy metals are less released from bottom ash than from fly ash. In this study the adsorption characteristics of heavy metals were investigated using various particle sizes of MSWI bottom ash. Since bottom ash has a broad particle size distribution, it was sieved to size classes of +20, -20, -48, -80, -100 mesh. Cation exchange capacity (CEC) was analyzed by the ammonium acetate method to evaluate the potential as an adsorbent. The CEC values and surface areas increase as the range of particle size becomes finer. The adsorption experiment was conducted using synthetic (Cu and Ni) and plating rinse water as a function of reaction time (10-180 min), liquid/solid ratio (2-100) and particle size (+20 to -100 mesh), respectively. The adsorption rate increased with decreasing particle size and with increasing liquid/solid ratio; however, the removal efficiency of Cu was higher than that of Ni. In the case of plating rinse water, the adsorption rate decreased sharply at high liquid/solid ratio, and it showed over 80% of adsorption rates for Cu and Ni at an initial pH of 3.