Fly ash exploited in pavement layers in environmentally friendly ways

Increased care about the environment is currently evidenced by governmental, industrial, and consumer concern for ozone depletion, solid and liquid waste disposal, and pollutants. This concern has led to an increase in marketing of the “environmentally friendly” aspects of products. In the past, fly ash was generally released into the atmosphere, but pollution control equipment mandated in recent decades now requires that it is captured prior to release. In order to upgrade expansive soils as construction materials, fly ash, which is a waste material, has been selected and successfully used for stabilizing expansive clays in the Thrace region. The strength characteristics of the stabilized soils were measured. Depending upon the soil type, the effective fly ash content for improving the engineering properties of the soil varied between 8% and 12%. Using fly ash in roadwork projects will help the environment reducing the deposited amounts.     

Characteristics and anthropogenic sources of carbonyl sulfide in Beijing

Atmosphericmixing ratios of carbonyl sulfide (COS) in Beijingwere intensivelymeasured from March 2011 to June 2013. COS mixing ratios exhibited distinct seasonal variation, with a maximumaverage value of 849 ± 477 pptv in winter and a minimal value of 372 ± 115 pptv in summer. The seasonal variation of COS was mainly ascribed to the combined effects of vegetation uptake and anthropogenic emissions. Two types of significant linear correlations (R² > 0.66) were found between COS and CO during the periods from May to June and from October to March, with slopes (ΔCOS/ΔCO) of 0.72 and 0.14 pptv/ppbv, respectively. Based on the emission ratios of COS/CO from various sources, the dominant anthropogenic sources of COS in Beijing were found to be vehicle tire wear in summer and coal burning in winter. The total anthropogenic emission of COS in Beijing was roughly estimated as 0.53 ± 0.02 Gg/year based on the local CO emission inventory and the ΔCOS/ΔCO ratios.     

Numerical modelling of the effects of vessel length-to-diameter ratio (L/D) on pressure piling

Pressure piling presents a major explosion hazard in interconnected process vessels. Pressure enhancement in the secondary vessel due to the acceleration of the flame through the connecting pipe can generate a disproportionately more violent explosion than would have been expected based on the concentration of dust in the secondary vessel. Pressure piling is a very complex phenomenon that is difficult to investigate through experimentation. Advanced computational fluid dynamics (CFD) modelling is a promising route to accurately account for all the complexities associated with pressure piling.In this paper, the current state of knowledge concerning pressure piling is presented. Further, the effects of varying the length-to-diameter ratio (L/D) of the primary vessel (Vessel 1) on pressure piling was investigated using numerical modelling. The volumes and volume ratio of the interconnected vessels were kept constant while the L/D of Vessel 1 was varied from 0.5 to 15. The simulations of coal dust explosion were performed using the coalChemistryFoam solver from OpenFOAM version 5.0.1. It is hoped that the findings from this study provide insight into the effects of the geometrical design of interconnected vessels, particularly L/D, on pressure piling. Additionally, this work has implications for the optimal placement of explosion isolation devices intended to actuate before the flame front and pressure escape to downstream vessels.     

生活垃圾焚烧飞灰制陶瓷砖

分析了飞灰的性质,利用飞灰、黄陶土、缸砂及文石研制陶瓷砖,并进行正交配比试验。结果表明:飞灰主要矿物成分是硅酸盐及铝硅酸盐,可用作陶瓷砖的原材料;飞灰的掺加量对陶瓷砖表观质量起决定性影响,最佳配比方案为飞灰25%,黄陶土55%,缸砂10%,文石10%;最佳配比制品浸出毒性均达标。     

煤矸石和粉煤灰pH与电导率动态变化规律及其相关性研究

煤矸石和粉煤灰是煤矿区两种常见的固体废弃物,对环境造成极大的污染。pH波动幅度大是废弃物农用治理的主要障碍之一。对两种废弃物连续浸提时的pH和电导率(EC)进行长期动态监测,结果表明,不同层次的煤矸石尽管风化程度不同,但经过长时间浸取后,pH和EC变化趋势相似,且煤矸石、粉煤灰的pH、EC值有很大的相关性。该试验为今后两种废弃物合理利用奠定了基础。     

MSWI BA treated with Advanced Dry Recovery: a field scale study on materials’ leaching properties

In many European countries, the environmental properties of waste-derived aggregates are mostly assessed based on laboratory leaching tests such as the standardised percolation tests CEN/TS/14405, ISO/TS 21268-3, or DIN 19528. These tests are conducted under specified conditions, which are similar yet somewhat different from realistic field conditions. Therefore, this study aimed to investigate the leaching properties of ADR (Advanced Dry Recovery) recovered MSWI BA in the field in order to understand more about its environmental impacts in actual civil engineering structures. Two field scale studies (a lysimeter and a larger interim storage field study) were constructed and the leachate quality was investigated. These results were then complemented with the results of previously conducted laboratory leaching tests using a liquid to solid ratio (L kg^?1) comparison. The results demonstrated that the leaching behaviours of many potentially harmful substances, such as chloride, copper and antimony, was similar despite the study scale. In addition, this study illustrated the importance of investigating the leaching properties of waste-derived aggregates on a larger scale, even though the uncertainties in such studies may not be easily controlled.     

泛比电阻电除尘器收尘性能实验研究

泛比电阻电除尘器是一种具有辅助电极和交错平板收尘电极的新型电除尘器.通过对其伏安特性及除尘效率的试验研究,并与传统线板式静电除尘器进行比较,结果表明辅助电极对电晕电流具有明显的抑制作用,在相同的外加电压下,泛比电阻电除尘器对高比电阻锅炉飞灰的收尘效率比普通的线板式电除尘器明显要高.     

煤气化过程中气态污染物采样分析的研究进展（续）

通过考察气态污染物采样方法的基本原理,对比分析国内外常压采样系统和加压采样系统的设计特征,选择煤气化过程中5种常见气态污染物为分析对象,列举常用的化学分析法和仪器分析法,为加压气化装置采样系统的设计提供参考材料和建议,归纳了一些有助于提高气态污染物检测数据可靠性的措施,希望能为煤气化过程中（特别是加压煤气化过程中）气态污染物采样系统的设计提供思路和借鉴。     

Bioaccumulation and translocation of metals in the natural vegetation growing on fly ash lagoons: a field study from Santaldih thermal power plant, West Bengal, India

A field study was conducted in the fly ash lagoons of Santandih Thermal Power Plant located in West Bengal (India) to find out total, EDTA and DTPA extractable metals in fly ash and their bioaccumulation in root and shoot portion of the naturally growing vegetation. Fly ash sample has alkaline pH and low conductivity. The concentration of total Cu, Zn, Pb and Ni were found higher than weathered fly ash and natural soil, where as Co, Cd and Cr were found traces. Five dominant vegetation namely, Typha latifolia, Fimbristylis dichotoma, Amaranthus defluxes, Saccharum spontaenum and Cynodon dactylon were collected in the winter months (November–December). Bioaccumulation of metals in root and shoot portions were found varied significantly among the species, but all concentration were found within toxic limits. Correlation between total, DTPA and EDTA extractable metals viz. root and shoot metals concentration were studied. Translocation factor (TF) for Cu, Zn and Ni were found less than unity, indicates that these metals are immobilized in the root part of the plants. Metals like Mn have TF greater than unity. The study infers that natural vegetation removed Mn by phytoextraction mechanisms (TF > 1), while other metals like Zn, Cu, Pb and Ni were removed by rhizofiltration mechanisms (TF < 1). The field study revealed that T. latifolia and S. spontaenum plants could be used for bioremediation of fly ash lagoon.     

燃煤锅炉烟气中CPM与水溶性离子监测方法及应用研究

建立燃煤锅炉烟气可凝聚颗粒物(CPM)与水溶性离子监测采样方法,并应用于北京市典型烟气净化工艺燃煤锅炉排放监测。结果表明,北京市燃煤锅炉烟气中总颗粒物(TPM)基准排放质量浓度最高达82.4 mg/m3,最低14.0 mg/m3,其中CPM占TPM的43.5%~92.2%,水溶性离子对TPM的贡献水平为31.4%~62.2%。烟温对水溶性离子的分布形态有显著影响,进而影响TPM中可过滤颗粒物(FPM)和CPM的分配比例。颗粒物和水溶性离子的排放与烟气含湿量之间无显著相关性,而与燃煤锅炉烟气脱硫除尘净化工艺和脱硫产物的溶解度及其脱除方式密切相关。