Influence of dustiness on small-scale vented dust explosions

A new safety characteristic the “dustiness” according to VDI 2263 – part 9 (Verein Deutscher Ingenieure, 2008) is investigated. Dustiness means the tendency of a dust to form clouds. The paper deals with the physical reasons for the different behavior of dusts, even if they have similar properties such as particle size and density and the influence of the dustiness on dust explosions. In order to study the effects of the dustiness on dust cloud formation for different dispersion methods experiments in a vertical dust dispersion glass tube apparatus were carried out. Furthermore vented dust explosion experiments were done for two different dispersion methods and two static activation pressures.Experiments show that particle size and density are not the only factors which influence dispersibility. Particle shape, specific surface area, flow and dispersion method have an influence which can outweigh size and density. Preliminary explosion experiments showed that the dustiness has an influence on the reduced explosion pressure and flame speed in a vented 75 L test apparatus. In order to verify the results for applications in the process industries further tests with industrial scale experiments are planned.     

协定水污染物间接排放标准的法律问题探究

以协商的方式确定水污染物间接排放标准的规定打破了人们对标准确定性、强制性的传统认识。协定标准的优势在于充分利用污水处理厂的污水处理能力,减轻企业的污水处理负担,使企业可以集中力量搞生产。协定标准具有灵活性和优越性,应充分利用。通过对协定标准概念和重要性的分析,指出协定标准存在效力不确定、缺少对协定范围的限制等问题,造成协定标准在实践中通常被忽视或者滥用。并从明确协定标准的范围、加强排污企业的管理和协定标准的监督等方面,进一步提出了限制和完善水污染物间接排放标准的建议。     

The Concepts of Energy,Environment, and Cost for Process Design

Abstract

The process industries (specifically, energy and chemicals) are characterized by a variety of reactors and reactions to bring about successful process operations. The design of energy-related and chemical processes and their evolution is a complex process that determines the competitiveness of these industries, as well as their environmental impact. Thus, we have developed an Enviro-Energy Concept designed to facilitate sustainable industrial development. The Complete Onion Model represents a complete methodology for chemical process design and illustrates all of the requirements to achieve the best possible design within the accepted environmental standards. Currently, NOx emissions from industrial processes continue to receive maximum attention, therefore the issue problem of NOx emissions from industrial sources such as power stations and nitric acid plants is considered. The Selective Catalytic Reduction (SCR) is one of the most promising and effective commercial technologies. It is considered the Best Available Control Technology (BACT) for NOx reduction. The solution of NOx Emissions problem is either through modifying the chemical process design and/or installing an end-of-pipe technology. The degree of integration between the process design and the installed technology plays a critical role in the capital cost evaluation. Therefore, integrating process units and then optimizing the design has a vital effect on the total cost. Both the environmental regulations and the cost evaluation are the boundary constraints of the optimum solution.     

Short-Term Opportunities for Decreasing CO2 Emissions from the Steel Industry

There is a strong political will to decrease CO₂ emissions. Although the steel industry only accounts for some 5% of worldwide CO₂ emissions (which totalled 1,200 million tonnes per annum in the late 1990s), it will be strongly affected by this. The EU, for example, is putting up strong economic incentives for reductions. This is taking place at a time when demand for steel products is greater than ever. To radically change existing processes and production routes to decrease the CO₂ emissions would be extremely expensive, even if it were possible. Nevertheless, many of the solutions which have been discussed seem to go in this direction. The other alternative discussed seems to be the creation of process solutions and alterations that lead to a focusing of CO₂ streams, i.e., much higher CO₂ concentrations in flue gases than today, for entrapment of the CO₂ so that it is not discharged into the atmosphere. These solutions are feasible, but expensive.

However, there exists today a number of solutions and technologies which, if fully implemented, could substantially decrease CO₂ emissions without seriously altering current methods of operation; they are short-term viable solutions. The present paper reviews and discusses such technologies, throughout the steel production paths. If these solutions are fully implemented, the combined impact on CO₂ emissions from the steel industry worldwide is estimated to be a reduction of 100–150 million tonnes of CO₂ per annum, i.e., current emissions can be reduced by some 8–10% within a relatively short time span.     

Exhaust Emissions from a Gas-fuelled S.I. Engine

Attempts to improve engine performance are often accompanied by increased emissions. An effective approach to reduce emissions without necessarily a significant penalty in fuel economy is through operating S.I. engines on a range of gaseous fuels, and either leaning the operating mixture or diluting it with some exhaust gases.

The emission characteristics of an engine operated in turn on CH₄, H₂, CO and some of their mixtures are examined experimentally. The role of changes in some key factors affecting the production of the pollutants CO, NOx and unburned hydrocarbons were investigated. Guidelines for reducing the undesirable emissions are outlined.     

乌海市高分辨率大气污染源排放清单构建及其在臭氧污染成因探究中的应用

乌海市是我国典型的煤焦化工业基地,大气污染物排放总量较大且近年来夏季O₃污染问题逐渐突出,明确大气污染物排放特征,探究O₃污染形成机制是客观认识其O₃污染现状,科学制定污染控制措施的基础.基于"系数法"采用自下而上的方式构建了2018年乌海市高分辨率大气污染源排放清单（HEI-WH18）,利用WRF-Chem对HEI-WH18的适用性和准确性进行评估,并结合模式诊断模块探究了乌海市夏季O₃污染形成的原因.排放清单结果表明,2018年乌海市SO₂、NO_x、CO、PM₁₀、PM_2.5、VOCs、NH₃、BC和OC的排放总量分别为65943、40934、172867、159771、47469、69191、1407、1491和1648 t ·a^-1.与MEIC清单相比,利用HEI-WH18能更好地捕捉到O₃及其前体物的排放变化规律和量级,适用于乌海市夏季O₃的模拟及其来源分析研究.从O₃及前体物的空间分布来看,乌海市海勃湾城区白天为O₃高值区,3个工业园区无论白天和夜间均为O₃低值区和NO₂高值区,CO的空间分布特征与煤层及矸石堆自燃源一致.根据对O₃污染过程的诊断分析,边界层中高层O₃浓度的升高主要是平流输送和化学过程共同作用的结果,低层O₃浓度的升高是垂直混合和平流输送导致的,化学过程在低层的贡献较为复杂,其正贡献起到了维持高O₃浓度的作用,负贡献结合平流输送造成了O₃污染的最终消散.     

Impact of anthropogenic heat emissions on meteorological parameters and air quality in Beijing using a high-resolution model simulation

• The Large scale Urban Consumption of energY model was updated and coupled with WRF. • Anthropogenic heat emissions altered the precipitation and its spatial distribution. • A reasonable AHE scheme could improve the performance of simulated PM_2.5. • AHE aggravated the O₃ pollution in urban areas. Anthropogenic heat emissions (AHE) play an important role in modulating the atmospheric thermodynamic and kinetic properties within the urban planetary boundary layer, particularly in densely populated megacities like Beijing. In this study, we estimate the AHE by using a Large-scale Urban Consumption of energY (LUCY) model and further couple LUCY with a high-resolution regional chemical transport model to evaluate the impact of AHE on atmospheric environment in Beijing. In areas with high AHE, the 2-m temperature (T₂) increased to varying degrees and showed distinct diurnal and seasonal variations with maxima in night and winter. The increase in 10-m wind speed (WS₁₀) and planetary boundary layer height (PBLH) exhibited slight diurnal variations but showed significant seasonal variations. Further, the systematic continuous precipitation increased by 2.1 mm due to the increase in PBLH and water vapor in upper air. In contrast, the precipitation in local thermal convective showers increased little because of the limited water vapor. Meanwhile, the PM_2.5 reduced in areas with high AHE because of the increase in WS₁₀ and PBLH and continued to reduce as the pollution levels increased. In contrast, in areas where prevailing wind direction was opposite to that of thermal circulation caused by AHE, the WS₁₀ reduced, leading to increased PM_2.5. The changes of PM_2.5 illustrated that a reasonable AHE scheme might be an effective means to improve the performance of PM_2.5 simulation. Besides, high AHE aggravated the O₃ pollution in urban areas due to the reduction in NO_x.     

青岛秋冬季PM1中金属元素污染特征及健康风险评估

于2018年11月1日至2019年1月31日（OP_2018-2019）和2019年11月1日至2020年1月20日（OP_2019-2020）在青岛对PM₁进行了连续两年秋冬季逐日采集.将观测期划分为4个空气质量等级（Ⅰ级、Ⅱ级、Ⅲ级和Ⅳ级）,分析了PM₁中金属元素浓度特征及来源,评估了不同人群的非致癌风险（Zn、Pb、Mn、Cu和V）和致癌风险（As、Cr、Ni、Cd和Co）.结果表明,与OP_2018-2019相比,OP_2019-2020期间不同空气质量等级下金属元素总浓度变化与Ca、K和Al浓度变化有关,受扬尘源和生物质燃烧源影响较大.与OP_2018-2019相比,OP_2019-2020期间不同空气质量等级下V浓度分别下降19.0%、60.5%、82.7%和77.5%.推测与船舶国内排放控制区域（DECA）政策实施有关,青岛周边海域船舶改换燃油品质,导致V浓度大幅降低.由富集因子、比值法和气流后向轨迹结果进一步表明V浓度变化主要受DECA政策影响.然而,实施DECA政策后,V/Ni值作为判断区域内受船舶源影响的限值,需进一步探究.由健康风险评估结果表明,OP_2018-2019和OP_2019-2020期间非致癌元素Mn的危险系数范围为0.07~1.22,建议加强管控含Mn污染源的排放.OP_2018-2019和OP_2019-2020期间不同空气质量下As、Cd的终生致癌风险概率（ILCR）值低于10^-4,但高于10^-6,表明存在致癌概率,但仍可接受.OP_2018-2019期间空气质量为Ⅳ级时,Cr的ILCR值高于10^-4,存在致癌风险.     

Identification of PM sources by principal component analysis (PCA) coupled with wind direction data

The effectiveness of combining principal component analysis (PCA) with multi-linear regression (MLRA) and wind direction data was demonstrated in this study. PM data from three grain-size fractions from a highly industrialised area in Northern Spain were analysed. Seven independent PM sources were identified by PCA: steel (Pb, Zn, Cd, Mn) and pigment (Cr, Mo, Ni) manufacture, road dust (Fe, Ba, Cd), traffic exhaust (P, OC + EC), regional-scale transport (, , V), crustal contributions (Al2O3, Sr, K) and sea spray (Na, Cl). The spatial distribution of the sources was obtained by coupling PCA with wind direction data, which helped identify regional drainage flows as the main source of crustal material. The same analysis showed that the contribution of motorway traffic to PM10 levels is 4-5 microg m-3 higher than that of local traffic. The coupling of PCA-MLRA with wind direction data proved thus to be useful in extracting further information on source contributions and locations. Correct identification and characterisation of PM sources is essential for the design and application of effective abatement strategies.     

Greenhouse gas emissions in Canada and Japan: sector-specific estimates and managerial and economic implications

Many firms generate large amounts of carbon dioxide and other greenhouse gases when they burn fossil fuels in their production processes. In addition, production of raw materials and other inputs the firms procure for their operations also generates greenhouse gases indirectly. These direct and indirect greenhouse gas emissions occur in many sectors of our economies. In this paper, we first present sector-specific estimates for such greenhouse gas emissions. We then show that estimates for such sector-specific greenhouse gas emissions are often required for various types of corporate as well as public policy analyses in both domestic and international contexts. Measuring greenhouse gas emissions resulting from firms' multi-stage production processes in a multi-sector context is relevant for policies related to the Kyoto protocol, an international agreement to limit global greenhouse gas emissions. For example, since the protocol allows firms to engage in trading and offsetting of their greenhouse gas emissions across national borders, provided that emissions are correctly measured, the firms can take advantage of such trading schemes by placing their energy-intensive production facilities globally and strategically. We present several case studies which illustrate the importance of this and other aspects of greenhouse gas emissions in firms' environmental management. We also argue that our modeling and estimation methods based on input-output analyses are suitable for the types of research goals we have in this paper. Our methods are applied to data for Canada and Japan in a variety of environmental management circumstances.