水泥企业硫排放量的计算与影响因素探讨

水泥窑系统中的硫主要来源于原煤燃料及石灰质、铁质等生料配料。通过总结生产经验数据,形成了脱硫设备前硫排放量理论经验公式,并根据理论计算结果,预先采取硫排放量控制措施,调整配料方案,控制入窑硫化物总量。同时,借助XRD检测仪器探究了原料中黄铁矿含量对硫排放量的影响,定性定量分析结果显示,原料中全硫含量相同时,黄铁矿含量越低,窑尾硫排放浓度越低,二者呈正相关。

石灰石-石膏湿法脱硫废水排放量深度解析

火电厂废水零排放势在必行,其主要难点之一为石灰石-石膏湿法烟气脱硫工艺的废水处置。为得出脱硫废水的合理排放量,以典型350 MW燃煤机组为例,从进入和排出脱硫系统的氯离子(Cl–)量入手,以脱硫吸收塔浆液Cl–平衡浓度控制为基准,对入炉煤、脱硫工艺水、脱硫石膏排出、脱硫废水排出等进行了Cl–物料平衡计算。在此基础上分析了脱硫系统深度优化和烟气深度治理等工程对脱硫系统水平衡的影响。

基于脱硫浆液氯离子浓度模型的脱硫废水排放优化控制研究

石灰石-石膏湿法烟气脱硫技术是我国燃煤电厂烟气脱硫的主流工艺,随着国家对环境问题日益重视,脱硫废水的排放处理问题亦深受关注。在脱硫系统运转中,脱硫浆液中氯离子会在吸收塔内富集,浆液中氯离子浓度过高会对脱硫系统运行造成不良影响,因此,为维持系统正常运转,需定量地排放脱硫废水以降低脱硫系统氯浓度,但脱硫浆液中氯离子浓度和脱硫废水的排放量涉及脱硫系统经济运行与后续零排放系统的规模等问题,是脱硫系统性能优化的重要参量。本研究模型揭示了电厂脱硫废水排放量和吸收塔内脱硫浆液氯离子浓度的内在关系,进一步指出应将电厂废水消纳能力作为废水排放量控制考虑的重要因素,给出了通过调控脱硫废水排放量实现吸收塔氯离子浓度控制的可实施方向。

Methane Dynamics in Northern Peatlands: A Review

Northern peatlands store a large amount of carbon and play a significant role in the global carbon cycle. Owing to the presence of waterlogged and anaerobic conditions, peatlands are typically a source of methane (CH4), a very potent greenhouse gas. This paper reviews the key mechanisms of peatland CH4 production, consumption and transport and the major environmental and biotic controls on peatland CH4 emissions. The advantages and disadvantages of micrometeorological and chamber methods in measuring CH4 fluxes from northern peatlands are also discussed. The magnitude of CH4 flux varies considerably among peatland types (bogs and fens) and microtopographic locations (hummocks and hollows). Some anthropogenic activities including forestry, peat harvesting and industrial emission of sulphur dioxide can cause a reduction in CH4 release from northern peatlands. Further research should be conducted to investigate the in fluence of plant growth forms on CH4 flux from northern peatlands, determine the water table threshold at which plant production in peatlands enhances CH4 release, and quantify peatland CH4 exchange at plant community level with a higher temporal resolution using automatic chambers.

Estimation of SO_2 emission factors from copper smelting industry in Yunnan Province,China

Copper smelting is a significant source of SO2 emission. It is important to quantify SO2 emissions from combustion sources for regulatory and control purposes in relation to air quality. The characteristics of SO2 emissions from copper smelting industry in Yurman Province, China, were examined. Analysis based on the present situation, material balance and measuring method were used to confirm SO2 emission factors of copper smelting industry. Results show that SO2 emission factors for Isa system, side blown-continuous converting system （SB-CC）, blast furnace-continuous converting systems （B-CC） and blast furnace-converter blowing （B-C） are 11.69-18.64, 62.44--101.4, 19.43-37.88 and 45.48-81.03 kg/t（blister copper）, respectively. The comprehensive emission factor based on all smelting plants is found to be in the range of 23-39.99 kg-SO2/t（blister copper） for Yunnan Province, China. The results are compared with those for discharge coefficients of industrial pollutants in the First National General Survey of Pollution Sources and the emission factor of the total amount of major pollutants. It is observed that there are some differences among emission factors.

Influence of dioxin reduction on chemical composition of sintering exhaust gas with adding urea

With the addition of urea as an inhibitor, four groups of reducing dioxin emission experiments in sintering pot were conducted. The results show that, adding 0.05%, 0.1% and 0.5% （mass fraction） urea, the emission concentrations of dioxin are 0.287 0.258 and 0.217 ng-TEQ/m3, respectively. The dioxin emission rates drop substantially compared to 0.777 ng-TEQ/m3 flee of urea. With an increase of the urea content, the concentration of SO2 emission reduces sharply. （NH4）2SO4, formed by the reaction of SO2 and NH3, goes into the dust and part of NH3 is released before reaction with the emission of exhaust gas. The NO~ emission presents an increasing trend because the reaction of NH3 and 02 at high temperature produces NOx. Based on the consideration of factors such as the effect of reducing dioxin emission, and the chemical composition of exhaust gas, 0.05% is the optimum adding content of urea.

A study of environmental impact on manufacturing products trade in Shandong,China

Based on the situation that the trade of manufactured goods takes the main position in Shandong Province,this paper identifies Shandong industrial pollutant discharge by three indices,which are industrial effluent discharge,industrial SO2 emission,and solid waste disposal.Furthermore,it conducts an empirical analysis of the trade terms of pollution content transfer on nine identified industrial sectors.The conclusion is that the increase in industrial effluent discharge,industrial SO2 emission,and solid waste disposal has paralleled the growth of the GDP in Shandong.The rapid economic growth brings obvious negative impact on the environment.Compared with that in 1998,the increase in the pollution content of exports in 2007 indicated that more environmental costs were generated with the economic development in Shandong.There is a need for optimization of foreign trade structure in Shandong,especially the need for increasing import of the pollution intensive products and decreasing the export of the pollution intensive products.The research on the relationship between manufactured goods trade and the environmental impact will make a contribution to the adjustment of foreign trade and environmental policies.

Environmental effects of export trade in the Yangtze River Delta, 2003-2006

Economic globalization has promoted the formation of global production network, and correspondingly the high-quality environmental factors are reconfigured behind the physical commodities exchange. Export trade not only drives China＇s economic growth, promotes industrial upgrading and technological progress, but also may have a negative impact on the environment. After reviewing and summarizing the existing relevant literatures, tire paper collects the required statistic data from 2003 to 2006 and uses the panel data model to measure the environmental effects of export trade in the Yangtze River Delta. The results show that the export trade of Yangtze River Delta has a negative impact on the environment. When the variables of economic scale, economic structure areftxed, with the export trade growth of 1%, the industrial sulfur dioxide emission and industrial waste water emtsston will increase by 0.12% and 0.23% respectively. So we must pay serious attention to the negative effects, and promote regional sustainable development rapidly through adjusting the export structure and strengthening environmental regulations.

Atmospheric Pollution due to Road Traffic Case of the Greater Casablanca Region

In the Greater Casablanca, road transport is the second largest emissions source of gaseous pollutants and particles after the industry [ 1 ]. The emitters are mobile and include different categories of vehicles in circulation, in the road network of the region [2]. Air emissions from road transport considered in this study are the exhaust emissions from combustion of fuel during vehicle movement. This is mainly SO2 （sulfur dioxide）, NOx （nitrogen oxides）, CO （carbon monoxide）, CO2 （carbon dioxide）, SP （suspended particulate） [3], VOC （volatile organic compounds）, benzene, lead Pb and cadmium. These emissions depend mainly on the technology of the vehicle （type, fuel, engine size, and age）, the vehicle speed, the engine temperature and ambient temperature [4].

Significant downward trend of SO_2 observed from 2005 to 2010 at a background station in the Yangtze Delta region,China

SO2 is an important gas in atmosphere with great environmental and climate implications.SO2 emission in China has been receiving great attention as the economy grows and the amount of coal consumption has increased in the past few decades.SO2 has been observed from July 2005 to June 2010 at Linan WMO GAW regional station(30.3 °N,119.73 °E,138 m a.s.l.) located in the Yangtze Delta region in eastern China.These observation data are analyzed to understand the trend of regional SO2 background concentration.Strict quality controls are conducted to ensure the temporal comparability of the data.Significant downward trend with ?2.4 ppb/yr(P < 0.0001) of surface SO2 is observed from 2005 to 2010,especially after 2008.The average concentration of SO2 from July 2005 to June 2008 is 14.2±3.1 ppb,which is slightly higher than the mean values of 13.5±5.1 ppb during 1999?2000 and is two folds of the average value(7.1±3.1 ppb) from July 2008 to June 2010.More than 50% of the SO2 has been cut down after 2008 in the Yangtze Delta region due to the implementation of stricter emission control measures.The peak SO2 concentration appears around 10 o'clock in the morning after 2009 while appears at night before 2009.These diurnal variations of SO2 might indicate that after 2009,more SO2 is from the vertical exchange process than from the local accumulation.

Carbon Dioxide and Nitrous Oxide Emissions from Naturally Occurring Sulfate-Based Saline Soils at Different Moisture Contents

Soil salinization may negatively affect microbial processes related to carbon dioxide （CO2） and nitrous oxide （N20） emissions. A short-term laboratory incubation experiment was conducted to investigate the effects of soil electrical conductivity （EC） and moisture content on CO2 and N20 emissions from sulfate-based natural saline soils. Three separate 100-m long transects were established along the salinity gradient on a salt-affected agricultural field at Mooreton, North Dakota, USA. Surface soils were collected from four equally spaced sampling positions within each transect, at the depths of 0-15 and 15-30 cm. In the laboratory, artificial soil cores were formed combining soils from both the depths in each transect, and incubated at 60% and 90% water-filled pore space （WFPS） at 25 ~C. The measured depth-weighted EC of the saturated paste extract （ECe） across the sampling positions ranged from 0.43 to 4.65 dS m-1. Potential nitrogen （N） mineralization rate and CO2 emissions decreased with increasing soil ECe, but the relative decline in soil CO2 emissions with increasing ECe was smaller at 60% WFPS than at 90% WFPS. At 60% WFPS, soil N20 emissions decreased from 133 g N20-N kg-1 soil at ECe （ 0.50 dS m-1 to 72 μg N20-N kg-1 soil at ECe = 4.65 dS m-1. In contrast, at 90% WFPS, soil N20 emissions increased from 262 g N20-N kg-1 soil at ECe ： 0.81 dS m-1 to 849 g N20-N kg-1 soil at ECe ： 4.65 dS m-1, suggesting that N20 emissions were linked to both soil ECe and moisture content. Therefore, spatial variability in soil ECe and pattern of rainfall over the season need to be considered when up-scaling N20 and CO2 emissions from field to landscape scales.