活性焦烟气净化技术及其在我国的应用前景

活性焦烟气净化技术是利用活性焦的吸附、催化功能对烟气进行深度净化的干法处理技术,可达到同时脱硫脱硝的目的。通过加热再生活性焦,可获得高浓度的SO2气体,用于生产硫酸、液体二氧化硫或硫磺,有效回收硫资源。该技术具有流程简单、占地面积小、无二次污染、费用低、应用范围广等特点。从机理、流程及经济可行性等方面对该技术进行了分析。针对我国国情及硫资源状况,提出活性焦烟气净化技术在我国有着良好的应用前景。     

电除尘专栏

前言电除尘器是治理烟尘、回收高价粉料的高效设备,不久的将来还可能发挥脱硫、脱硝作用。我国电除尘器处理的烟气量每年达12000亿米~3以上,火电厂烟气已有四分之一(即1.5亿米~3/小时)经电除尘器净化。在     

高温分解及烟气净化处理电子垃圾的技术和设备

提出高温分解及烟气净化处理废弃电子垃圾的技术。通过喷水系统调节分解炉内气氛,控制有机物分解速度,使有机物裂解成二氧化碳和水蒸气,有害成份经净化系统再次处理后达到环保排放标准。金属部分可进一步进行提炼回收,实现有机物和金属的绿色分离。     

平板陶瓷膜回收烟气水热的实验研究

将平板陶瓷膜组成膜组件对烟气水分和余热进行回收,考察了烟气的温度、相对湿度、流速和冷却水温度等参数对膜组件水热回收性能的影响。在实验工况下,水通量和水回收效率随着烟气温度、烟气相对湿度的增加和冷却水温度的降低而上升;水通量随着烟气流速的加快而上升,水回收效率随着烟气流速的加快先上升后降低;膜组件的水通量和水回收效率最高分别可达22.0 kg/(m²·h)和36.3%。平板陶瓷膜回收的热量主要来自烟气潜热,烟气潜热换热量与水通量呈正相关变化趋势。在实验工况下,平板陶瓷膜组件的总传热系数最高为412 W/(m²·℃),高于多通道管式陶瓷膜和单通道管式陶瓷膜。     

炭素焙烧炉沥青烟气的净化处理

平顶山市炭素厂以焦炭细末和中温煤沥青为主要原料生产炭素。由于炭素生坯块的主要原料是焦炭细末和作为粘结剂的沥青，所以，在炭素生坯块的焙烧过程中有沥青烟气产生。沥青烟气不仅危害人体健康，而且污染环境，必须对其进行治理。     

垃圾焚烧炉烟气净化系统的工艺分析

介绍了两种垃圾焚烧电厂烟气净化处理工艺,分析了垃圾焚烧烟气净化处理装置工艺流程及出口排放参数,提出目前适合的处理工艺及发展方向。     

垃圾焚烧及烟气净化技术分析

分别阐述了垃圾焚烧系统的类型及烟气净化的系统配置，并以工程实践中的多种烟气净化设备配置为例，分析了这些配置的优缺点。     

氟化工废水处理技术

六氟丙烯高浓度氟盐废水,采用20%左右的Ca(OH)2乳液沉淀除F-、CO32-,回收KOH溶液,回用于生产中,达到废水零排放.生产中的浓缩装置废水、悬浮聚合物废水、PTFE净化R22废水和分散聚合4股含氟有机废水经混合后,采用石灰沉淀、铝盐絮凝除氟-生物接触氧化处理工艺,处理出水F-小于10 mg/L,COD小于l50 mg/L,BOD5小于30 mg/L,达到了规定的排放标准.     

国外动态

西德Degussa公司开发成功利用过氧化氢净化烟气进行脱硫的新工艺,这种工艺过程适用于50兆瓦以上负荷的烧油加热炉或烧煤炉窑的烟气脱硫,还可用于净化工业装置含SO_2的废气。采用这种工艺,可使净化后烟气或气体中剩余SO_2小于20毫克/米~3,同时,可生成70％(重)的浓硫酸,使整个工艺过程的费用降低。     

危险废物焚烧厂烟气净化工艺设计与探讨

参考国内外已有的危险废物焚烧工程相关设计和研究资料,针对国内具有代表性的危险废物成分,采用设计计算得到危险废物焚烧烟气的污染物初始浓度,分析成熟的烟气净化工艺,对适合中国危险废物特点的危险废物焚烧厂烟气净化工艺进行了设计和探讨,为危险废物焚烧厂建设单位及设计单位等提供参考。     

我国废橡胶粉用于沥青改性的研究及应用

从道路建设与防水卷材制造两方面,描述了我国废橡胶粉在沥青改性用途中的研究及应用现状。大量国内试验及应用实例表明,与普通石油沥青相比,胶粉改性沥青的针入度、延度、软化点、温度敏感性、稳定性和抗老化性等性能均得到了改善。此外,较之其他种类的沥青改性剂,废橡胶粉成本低,具有环保与资源节约的优点,对我国循环经济的发展具有重要意义。     

温和的高温高压条件对磺化沥青可生物降解性的影响

在氮气氛围下,采用温和的高温高压对模拟磺化沥青废水进行预处理,考察了预处理时间、温度和压力对磺化沥青可生物降解性的影响,得出最佳工艺条件为预处理时间40 min,预处理温度220 ℃,预处理压力7 MPa,采用最佳条件预处理后的磺化沥青废水经活性污泥处理后,COD去除率达80.0%,COD_B/COD为0.82,一级反应速率常数达0.123 5 h^-1。对预处理前后磺化沥青的表征结果显示,经高温高压处理后的磺化沥青主要成分仍是烷烃和芳香族化合物等,但发生了脱磺水解反应,长链烷烃和苯系物的含量大幅下降,低分子量直链烷烃含量升高。     

Leachability of Cr(VI) and other metals from asphalt composites with addition of filter dust

The potential use of filter dust in asphalt composites for road construction was investigated. Filter dust contains high concentrations of metals, of which Cr(VI) and Pb are leached with water. Compact and ground asphalt composites with addition of 2% of filter dust by mass were studied. In order to evaluate their environmental impact, leachability tests were performed using water and salt water as leaching agents. The concentrations of Cr(VI) and Pb were determined in leachates over a time period of 182 days. The results indicated that Pb was not leached with leaching agents from asphalt composites. Cr(VI) was also not leached with leaching agents from compact asphalt composites. However, in ground asphalt composites, Cr(VI) was leached with water in concentrations up to 220 microg L(-1) and in salt water up to 150 microg L(-1). From the physico-mechanical and environmental aspects, filter dust can be used as a component in asphalt mixtures.     

A study on engineering characteristics of asphalt concrete using filler with recycled waste lime

This study focuses on determining the engineering characteristics of asphalt concrete using mineral fillers with recycled waste lime, which is a by-product of the production of soda ash (Na(2)CO(3)). The materials tested in this study were made using a 25%, 50%, 75%, and 100% mixing ratio based on the conventional mineral filler ratio to analyze the possibility of using recycled waste lime. The asphalt concretes, made of recycled waste lime, hydrated lime, and conventional asphalt concrete, were evaluated through their fundamental engineering properties such as Marshall stability, indirect tensile strength, resilient modulus, permanent deformation characteristics, moisture susceptibility, and fatigue resistance. The results indicate that the application of recycled waste lime as mineral filler improves the permanent deformation characteristics, stiffness and fatigue endurance of asphalt concrete at the wide range of temperatures. It was also determined that the mixtures with recycled waste lime showed higher resistance against stripping than conventional asphalt concrete. It was concluded from various test results that a waste lime can be used as mineral filler and, especially, can greatly improve the resistance of asphalt concrete to permanent deformation at high temperatures.     

A performance study on asphalt concrete mixes with different waste materials as modifiers in pavement application

Journal of Material Cycles and Waste Management - In this study, the physical properties of modified asphalt binders and performance of asphalt mixes after the addition of different modifiers such...     

Stabilization and utilization of hospital waste as road and asphalt aggregate

This article reports the operational results of the effective utilization of hospital waste molten slag produced using a high-temperature melting system, and being operated at a hospital in Selangor, Malaysia. The hospital waste is incinerated and subsequently melted at 1200°C. Scanning election microscope (SEM)/EDX results showed that the slag produced after melting contained amounts of SiO₂, CaO, and Al₂O₃ in excess of 53%, 9%, and 16%, respectively. The results from a leaching analysis on the slag produced proved that the melting process had successfully stabilized the heavy metals. The use of this slag as an alternative material to replace conventional aggregates for road construction was studied. The results from aggregate and asphalt mix tests showed that the slag produced fulfills all the requirements of an alternative aggregate. The average asphalt content, or the optimum asphalt content to be mixed with hospital waste molten slag, was found to be about 5.53%.     

Laboratory study on solidification/stabilization of unwanted medications using asphalt as a binder

The rise in discarded or unwanted medications (UMs) is becoming an issue of great concern, as it has the potential to harm the components of the environment where it is discarded: particularly air, water and soil. To combat this problem, many researchers have investigated the best approach for the collection and proper disposal of UMs. This paper intends to elaborate upon a safe solution for treating this waste, specifically through a process of solidification/stabilization (S/S) that involves mixing UMs with asphalt cement and asphalt concrete mixtures. Volumes of 5, 10, 15 and 20 % of a mixture of UMs were mixed with asphalt cement and the analyzed properties of the mixture of UMs–asphalt included: softening point, ductility, penetration, flash and fire points, specific gravity and rotational viscosity. Marshal stability, flow, air voids, unit weight, voids in mineral aggregate (VMA) and voids filled with binder (VFB) of asphalt concrete mixture were also investigated. Results showed that this approach of S/S is a promising method for dual achievements to solve an environmental problem and to use the waste for road construction.     

Recycling building demolition waste in hot-mix asphalt concrete: a case study in Kuwait

Building demolition waste constitutes a major component of municipal solid waste in Kuwait. Over 90% of this waste is currently land-filled, causing extreme pressure on the available land-fill sites. At the same time, the sources of natural aggregates are almost depleted, and there is an increasing demand because of the increased construction and maintenance activities. This article presents the results of a technical feasibility study into meeting this need by recycling the aggregates obtained from building demolition waste for asphalt concrete. The Marshall test, the immersion compression test, the loss of stability test, and the wheel track test were performed to evaluate the asphalt concrete made with recycled aggregate. The results showed that the asphalt concrete produced using an aggregate of demolition waste met all the requirements of local specifications.     

Performance of recycled ceramic waste as aggregates in hot mix asphalt (HMA)

Ceramic waste materials from the production of titles has increased over the years. Preliminary studies on the properties of ceramics showed that this material can be incorporated into asphalt mixtures as aggregates. Laboratory tests were conducted to evaluate the feasibility of utilizing ceramic materials from tile manufacturing firms. A study was undertaken to look into the performance of crushed ceramics that were incorporated in asphalt mixtures to replace the conventional granite aggregates from sizes 5.0 mm down including the 75 micron filler. The replacement was done proportionally with a 0, 20, 40, 60, 80, and 100% percent by weight of granite aggregates. The outcome of the study showed that the performance of recycled ceramic aggregates in hot mix asphalt (HMA) reached an optimum at about 20% which means there is a great potential for the use of it in asphalt mixtures. The Marshall stability showed an increment of about 25% while the resilient modulus strength improved by 13.5% as compared with the control specimen. All samples were analyzed at various proportions of ceramic–granite aggregate combination and were observed that a 20% use of 5 mm down ceramic aggregates blended with granite aggregates produce higher strength HMA.     

Contributions of common sources of polycyclic aromatic hydrocarbons to soil contamination

Asphalt products, particularly sealants, are prepared using petroleum products that contain a com‐plex mixture of aliphatic and aromatic hydrocarbons, including polycyclic aromatic hydrocarbons (PAHs). Clearly, these products are ubiquitous in urban environments, which raises an issue regard‐ing the potential for PAHs to be transported from parking lots to underlying or adjacent soil, surface‐water bodies, or groundwater. Based on a literature review, there are limited studies focus‐ing on this issue; however, the studies that have been published have fascinating conclusions. The literature shows, as expected, that asphalt‐based products contain PAHs. The highest PAH concen‐trations are present in asphalt sealants, particularly those manufactured using coal tar. Furthermore, due to the low solubility and high partition coefficients of PAHs, the potential for PAHs to leach from asphalt surfaces is negligible, which has been confirmed by leachability studies. Thus, there is little risk that PAHs will be present in stormwater runoff or leach into groundwater from asphalt‐paved areas in a dissolved form. However, asphalt pavement and sealants produce particulate matter that can contain concentrations of PAHs in the sub‐percent range (100s to 1,000s mg/kg total PAHs) that is transported in stormwater runoff. Some studies show that this can cause soil and sediment con‐tamination with total PAH concentrations in the range of 1 to 10 mg/kg. From a remediation per‐spective, many site cleanups are conducted to remediate the presence of PAHs to cleanup goals below 1 mg/kg or, in some cases, 0.1 mg/kg or lower. From a total risk perspective, remediating sites to low PAH cleanup goals may be unwarranted in light of the risk of transportable PAHs produced from paved parking surfaces. In other words, is it reasonable to conduct a cleanup to remediate low PAH concentrations and then redevelop the area with asphalt pavement and sealant, which may pose a greater PAH‐related risk? © 2006 Wiley Periodicals, Inc.