燃煤锅炉的氧腐蚀机理研究及防护措施

针对河北省某厂的燃煤锅炉的烟管腐蚀问题,通过水质分析、采集腐蚀处的产物,进行XRD、扫描电镜、能谱分析等手段分析腐蚀产生原因和腐蚀速率的影响因素.发现烟管与水接触侧发生了氧腐蚀.水垢附着速率、溶解氧含量这两种因素对腐蚀速率影响较大.并针对锅炉材质、锅炉设计、水质处理、停炉保养、人员素质等方面提出改进措施,为今后处理类似问题提供经验和参考.     

Coal mining and the resource community cycle: A longitudinal assessment of the social impacts of the Coppabella coal mine

Two social impact assessment (SIA) studies of Central Queensland's Coppabella coal mine were undertaken in 2002–2003 and 2006–2007. As ex post studies of actual change, these provide a reference point for predictive assessments of proposed resource extraction projects at other sites, while the longitudinal element added by the second study illustrates how impacts associated with one mine may vary over time due to changing economic and social conditions. It was found that the traditional coupling of local economic vitality and community development to the life cycle of resource projects—the resource community cycle—was mediated by labour recruitment and social infrastructure policies that reduced the emphasis on localised employment and investment strategies, and by the cumulative impacts of multiple mining projects within relative proximity to each other. The resource community cycle was accelerated and local communities forced to consider ways of attracting secondary investment and/or alternative industries early in the operational life of the Coppabella mine in order to secure significant economic benefits and to guard against the erosion of social capital and the ability to cope with future downturns in the mining sector.     

水煤浆技术应用现状及对策分析

文章对水煤浆技术在工业化应用过程中出现的技术问题进行了分析并提出了相应的对策。     

Preparation and characterization of carbon-enriched coal fly ash

Carbon-enriched fractions have been obtained from two coal fly ash (FA) samples. The FA came from two pulverized-coal fired power stations (Lada and Escucha, Spain) and were collected from baghouse filters. Sieving was used to obtain carbon-enriched fractions, which were further subjected to two beneficiation processes: acid demineralization using HCl and HF, and oil agglomeration using soya oil-water. Yield in weight after sieving, unburned carbon content, and several physicochemical characteristics of the obtained fractions were used to compare the performance of the beneficiation methods. Low carbon concentration was obtained by sieving, particularly in the case of Escucha FA. However, after acid demineralization or oil agglomeration, fractions containing unburned carbon in a range of 63% to 68% were obtained. These fractions showed differences in mineral phase composition and distribution depending on the FA and on the beneficiation method used. The textural properties of the obtained fractions varied as a function of their carbon content and the beneficiation method used. However, no significant differences in morphology of the carbonaceous particles were found.     

Using trace element concentrations in Corbicula fluminea to identify potential sources of contamination in an urban river

We used the biomonitor, Corbicula fluminea, to investigate the contributions of trace elements associated with different point sources and land uses in a large river. Trace elements were analyzed in tissues of clams collected from 15 tributary streams draining five land use or point source types: agriculture, forest, urban, coal-fired power plant (CFPP), and wastewater (WWTP). Clams from forested catchments had elevated Hg concentrations, and concentrations of arsenic and selenium were highest (5.0+/-0.2 and 13.6+/-0.9 microg g(-1) dry mass (DM), respectively) in clams from CFPP sites. Cadmium concentrations were significantly higher in clams from urban and CFPP sites (4.1+/-0.2 and 3.6+/-0.9 microg g(-1) DM, respectively). Non-metric multidimensional scaling (NMS) of tissue concentrations in clams clustered at CFPP and forest/agriculture sites at opposite ends of the ordination space, and the distribution of sites was driven by Cu, Zn, Cd, and Hg.     

Reduced mercury deposition in New Hampshire from 1996 to 2002 due to changes in local sources

Changes in deposition of gaseous divalent mercury (Hg(II)) and particulate mercury (Hg(p)) in New Hampshire due to changes in local sources from 1996 to 2002 were assessed using the Industrial Source Complex Short Term (ISCST3) model (regional and global sources and Hg atmospheric reactions were not considered). Mercury (Hg) emissions in New Hampshire and adjacent areas decreased significantly (from 1540 to 880 kg yr⁻¹) during this period, and the average annual modeled deposition of total Hg also declined from 17 to 7.0 μg m⁻² yr⁻¹ for the same period. In 2002, the maximum amount of Hg deposition was modeled to be in southern New Hampshire, while for 1996 the maximum deposition occurred farther north and east. The ISCST3 was also used to evaluate two future scenarios. The average percent difference in deposition across all cells was 5% for the 50% reduction scenario and 9% for the 90% reduction scenario.     

Economic liabilities of environmental pollution by coal mining: Indian scenario

India is the first country to introduce environmental legislation in the constitution but because of lengthy legal procedures, it is very difficult to control environmental deterioration. There are many factors responsible for this deterioration. Coal mining is one such activity where deterioration is very severe and the present communication aims this aspect. Coal is the one of the most essential mineral having large reserves in India. It’s mining and beneficiation produce a variety of pollutants. The main pollutants emitted during the processing of coal are green house gases, coal dust and acid mine drainage. Many reports on different aspects of coal mining are available including reports on emission of different pollutants but the present work is probably only of it’s kind in which the authors have tried to determine environment liability directly in terms of economy. It was found that greenhouse liabilities, coal dust liability and sulphur liability are accounted for 12.07, 5.0 and 101.97 US$, making an overall 2.4% of the total economic gains due to coal mining. During the calculations approximate number of total workers and other parameters have been taken into consideration. Who pays for this irreversible damage is a question. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.     

Aqueous accelerated solvent extraction of native polycyclic aromatic hydrocarbons (PAHs) from carbonaceous river floodplain soils

In this study, three river floodplain soils with different compositions of carbonaceous materials and a reference coal sample were extracted with water using the accelerated solvent extraction (ASE) method. The desorption enthalpy values for 2-ring PAHs were highest in the coal sample, with values in the soil samples decreasing with decrease in coal content. The values for the higher condensed PAHs showed that the highest desorption enthalpies were from the samples with the largest amount of coal-derived particles. Elevated desorption enthalpies indicated a strong bonding between PAHs and geosorbents. Moreover, with the application of ASE this study was able to conclude that the PAHs in the samples were preferentially adsorbed to carbonaceous materials with high surface areas.     

粉煤灰吸附含镍废水的研究

采用EDTA滴定法以热电厂废弃物粉煤灰为吸附剂,对含镍废水进行了吸附研究,模拟测定了影响粉煤灰吸附工业废水中重金属离子的几种因素。结果表明:低温,高的镍离子浓度,粉煤灰颗粒细、数量多能提高粉煤灰的吸附效能。同时这种方法简便,成本低廉,能达到以废治废的目的。     

燃煤高温固硫的机理及固硫影响因素探讨

燃烧中固硫是一种适合我国国情的燃煤脱硫技术。本文探讨了燃煤高温固硫过程的主要反应机理和一些常用固硫添加剂的助固硫作用,分析了影响固硫效率的主要因素,进而提出实际应用中应考虑的提高固硫效率的措施。