due to ambiguities in the estimation methodologies employed to evaluate mobile sources. The main sources of mercury emissions to atmosphere in Japan are coal–fired cement plants, accounting for over 30% of the total emissions in the year 2006. On the other hand, industrial emissions from primary ferrous metal production and coal–firedpowerplants had a significant contribution of atmosphericmercury emissions in Japan in 2006. The assessment of mercury concentrations in the local atmosphere in Japan was performed using two different atmosphericdispersion models, i.e., the AIST–ADMER and the METI–LIS. The results of the present study indicated that the annual mean ambient concentrations of mercury in residential areas generally amounted to be less than 0.22 ng/m 3 (0.00022 μg/m 3 ), but there are no sites that exceed 0.04 μg/m 3 near industrial point sources. Though it is unrealistic to expect the Gaussian models to predict the real situation of mercury concentration in the local atmosphere, the major purposes of the present assessment was to conduct a methodology of comprehensive analysis of exposure and atmospheric distribution of mercury concentration, and thereby to develop a detailed picture of current air quality assessment of the different industrial areas of Japan.
Mercury can also be returned to the rivers as part of sediments, and high concentrations of mercury in sediment can be found near sources of mining. If the mercury compound is soluble the mobility of the mercury in the environment is greater, although cases of enhanced solubility are also of concern. During rainy seasons, when the water flow is rapid and turbid, and the solids load is high, the lateral and downstream transport of mercury is more favourable due to the amount of suspended material (VanLoon and Duffy, 2005). In the sediments at the surface, oxidation of mercury occurs forming a soluble mercury (II) chloro species that can be accumulated in the plants growing in nutrient rich waters. According to VanLoon and Duffy (2005) and Cheng et al. (2009) fish can take up methylated mercury when sediments contain organic matter and, as mentioned in the previous section, is the major species of mercury found in fish (Cheng et al., 2009; VanLoon and Duffy, 2005). Mercury is observed in plants, also an important component of human diet, in areas exposed to sources of mercury. In Massachusetts, humans are warned to avoid consuming the local fish as a result of the unsafe mercury levels. It is suspected that the primary source of mercury contamination to these water bodies is due to atmosphericmercury deposition from long range transport and near field point sources as a result of anthropogenic or natural sources (Hutcheson et al., 2008).
Meteorological input data for the modeling runs are processed using the National Center for Atmospheric Re- search (NCAR) 5th generation Mesoscale Model (MM5, v3.0) [18,19].Important MM5 parameterizations and physics options apply to each summer include mixed phase microphysics, planetary boundary layer (PBL), and the land surface module. Meteorology-Chemistry Interface Processor (MCIP, v2.0) is used to process the MM5 output fields and generate the meteorological pa- rameter fields required by SMOKE and CMAQ as well as the dry deposition velocity fields of chemical species required by CMAQ.
Abstract. Comprehensive field measurements are needed to understand the mercury emissions from Chinese powerplants and to improve the accuracy of emission invento- ries. Characterization of mercury emissions and their behav- ior were measured in six typical coal-firedpowerplants in China. During the tests, the flue gas was sampled simul- taneously at inlet and outlet of Selective Catalytic Reduction (SCR), electrostatic precipitators (ESP), and flue gas desulfu- rization (FGD) using the Ontario Hydro Method (OHM). The pulverized coal, bottom ash, fly ash and gypsum were also sampled in the field. Mercury concentrations in coal burned in the measured powerplants ranged from 17 to 385 µg/kg. The mercury mass balances for the six powerplants varied from 87 to 116% of the input coalmercury for the whole sys- tem. The total mercury concentrations in the flue gas from boilers were at the range of 1.92–27.15 µg/m 3 , which were significantly related to the mercury contents in burned coal. The mercury speciation in flue gas right after the boiler is in- fluenced by the contents of halogen, mercury, and ash in the burned coal. The average mercury removal efficiencies of ESP, ESP plus wet FGD, and ESP plus dry FGD-FF systems were 24%, 73% and 66%, respectively, which were similar to the average removal efficiencies of pollution control de- vice systems in other countries such as US, Japan and South Korea. The SCR system oxidized 16% elemental mercury and reduced about 32% of total mercury. Elemental mercury, accounting for 66–94% of total mercury, was the dominant species emitted to the atmosphere. The mercury emission factor was also calculated for each power plant.
Mercury is a toxic heavy metal, with a complicated biogeochemical cycle due to its various species. Mercury emissions to the atmosphere come mainly from anthropogenic activities, and among them, coal combustion is considered to be the dominant contributor. Seawater flue gas desulfurization (SFGD) system has been widely adopted in coal-firedpowerplants (CFPPs) of China coastal region. Defferent from other flue gas desulfurization techniques, where the influence of CFPPs on surrounding atmosphere is only dominated by stack emission, the mercury transfer from post-desulfurization seawater of a SFGD system to air should not be ignored. Therefore, it is meaningful to study the influence of mercury discharged from CFPPs equipped with SFGD system on surrounding atmosphere.
according to the national energy technology laboratory (netl)’s 2007 coalPower Plant database (http://www.netl. doe.gov/energy-analyses/technology.html), 33 coal-firedpowerplants have being operated in Ohio. dispersionmodeling was conducted for the top two mercury-emitting coal-firedpowerplants. atmosphericmercury concentrations, dry mercury deposition rates, and wet mercury deposition rates were predicted on a 500 m cartesian grid up to 5 km far from those powerplants. Meteorological data used in the dispersion model were analyzed to examine meteorological influences on mercury deposition rates.
In order to complete the overview on the novel PSA-based system configurations, a comparative analysis is carried out with the most common arrangement for power and ultrapure H2 coproduction in IGCC plants. It consists of an absorption unit for processing the shifted syngas followed by a PSA for further H2 purification. The related results refer to two studies, selected after a screening of the relevant literature. Intro- ducing the production of ultrapure H2 appears to be more effective when also the CO2 separation is carried out through a PSA process, as can be argued by the cumulative efficiency. The main advantage is that PSA technology allows avoiding the power consumption related to PSA tail gas compression, common in the configuration including absorption. Between the two proposed options, the Two-train PSA configuration demonstrated to perform better in terms of energy efficiency. Although the discussed advantages of the novel configu- rations presented, the general viability has yet to be proven since PSA integration into an IGCC plant has normally a lower overall performance than absorption. It needs to be evaluated if the benefits introduced with ultrapure H2 coproduction are sufficient to make up for this initial performance gap. The scattering of results in the literature makes this evaluation not straightforward. A possible solution would be to utilize a common modeling framework to assess the performance of both options. Other issues may also arise when adopting PSA technology, among those the need for controlling the fluctu- ations in the H2-rich gas rate to the gas turbine due to the PSA cyclic operation. Lastly, this is a very first assessment of such system entirely based on PSA technology. A further optimi- zation is likely feasible, exploiting developments in the pro- cesses and in the materials (e.g. adsorbents effectively performing at high temperatures allowing for warm gas cleaning processes). Moreover a simplification of the PSA layout is possible with advantages in terms of footprint. In particular the Two-train PSA configuration relies on a fairly complex second PSA cycle, which was developed to obtain high H2 recovery. Since that is not an important requirement in the case proposed, an easier PSA cycle could be advisable.
Manzanillo, Colima is situated in the Pacific Coast of Mexico. Population in the city is approximately of 161,420 inhabitants and has a total surface of 1578.4 km²; being the biggest municipality of the Colima State. Cli- mate is sub-humid warm (Aw) with summer rains, tem- perature ranges from 22˚C to 28˚C. Since Mexico is in- fluenced by the monsoon, the study area shows two pe- riods well defined: the dry season (from November to Mayo), and the rainy season (from June to October). Figure 1 and Table 1 show the geographical position and main characteristics of the sampling site. High ex- cess sulfate has been reported in rainwater samples in Manzanillo , and it has been concluded that this sul-
were only available for larger powerplants. As a consequence, 19 countries had no data on control technologies. However, the total capacity of plants with missing control technology data is only 14.15 GW, representing 0.78% of the total coal capacity in the study. We assigned those missing as 0 reduction in the following analysis. We defined national SO x reduction as the average SO x reduction percentage weighted by generating capacities of indi-
Table 2 presents the thermodynamic analysis results of the conventional WHUS. The inlet flue gas temperature of the LTE is equal to that of the exhaust flue gas from the air preheater, which is 131 °C. Meanwhile, due to the relatively low sulfur content of the coal (approximately 0.17%), as well as the acid steam wraparound effect brought by the flying ash, the outlet flue gas temperature of the LTE can be reduced to 100°C without serious corrosion problem.. According to the relevant thermodynamics theories, the smaller the temperature difference between the working mediums, the smaller heat transfer exergy destruction. In this case, higher condensed water temperature is preferred, given the fixed flue gas temperature range. In related heat transfer and techno-economic theories, however, a small heat transfer temperature difference increases the heat transfer area and the volume of the heat exchange device. As a result, investment in the heat exchanger is heightened. To balance the thermodynamic performance and equipment investment in the conventional WHUS, LTE adopts the counter-current arrangement and is connected in parallel to RH6. By this arrangement, on the one hand, provided that the engineering constraint is allowed, the condensed water temperature is enhanced as high as possible. As seen in Table 2, considering the flue gas temperature of the LTE is only 131–100 °C, which can only be used to heat the condensed water of RH6 at most (83.3–122.1 °C). On the other hand, the outlet condensed water temperature of LTE is set to 116 °C, slightly lower than 122.1 °C, which ensures the minimum heat transfer temperature difference of the LTE is maintained over 15 °C . Overall, the total investment of the conventional WHUS could be maintained at a relatively acceptable level. Meanwhile, the net power output is increased by 5.83MW, whereas the heat rate of the generation unit is reduced by 42.56 kJ /kWh.
AERMOD is a near field and steady-state guideline model in that it assumes that concentrations at all distances during a modelled hour are governed by a set of hourly meteorological inputs, which are held constant (Cimorelli et al. , 1998 ). Using available meteorological data and similarity theory scaling relationships associated with the geographical location of the Logbaba thermal power plant, we used AERMOD to construct hourly gridded vertical profiles of required me- teorological variables. These variables include wind speed, wind direction, as well as vertical and horizontal turbulences, which are used to calculate plume rise, transport and dispersion of each plume as described by Perry (Perry et al. , 2004 ).
The association between per capita coal capacity and lung cancer incidence can be used to understand the potential number of lives affected by different levels of reliance on coalpower. In 2015, we estimate a total of 865,805 male and 542,848 female standardized lung cancer cases can be attributed to anthropogenic powerplants using coal as primary energy source. There is little difference between the lag 5 and lag 10 models in terms of quadratic information criterion (QIC)(Pan 2001) and coefficients, so for sake of consistency with the other covariates, we fix lag 10 for coal capacity as primary model and estimate PAFs. These numbers should be interpreted as the total attributable cases given every country has WHO 2000-2025 standardized population and should not be compared directly to other estimations. However, these numbers adjust for age distributions in different countries and can be a valuable tool for country-to-country comparisons of the effect fromcoal capacity.
Coal petrography employs various methods of investigation. In methods of optical microscopy, for example, the specimen may be viewed in air or in immersion; both transmitted-light and reflected-light methods are used, and the light may be ordinary, polarized, or ultraviolet. Specimens may be separated into groups of components of similar density in heavy liquids (mixtures, for example, of C 6 H 6 , CCl 4 , or CHBr 3 ). Maceration methods are used to identify and then study stable components. Etching with strong oxidizers is employed to reveal the cryptographic structure of coal. Thermal and chemical analyses may be conducted of components or groups of components of coal samples. Quantitative methods are of great importance. They include the determination of the reflectance, refractive index, and hardness of vitrinite; the establishment of the color and brightness of luminescence of liptinite; and the calculation of the content of components in average bed samples and in chunks of coal.
The power sector needs to be decarbonised by 2050 to meet the global target for greenhouse gas emission reduction and prevent climate change. With fossil fuels expected to play a vital role in the future energy portfolio and high efficiency penalties related to mature CO 2 capture technologies, this research aimed at evaluating the efficiency improvements and alternate operating modes of the coal-firedpowerplants (CFPP) retrofitted with post-combustion CO 2 capture. To meet this aim, process models of the CFPPs, chilled ammonia process (CAP) and calcium looping (CaL) were developed in Aspen Plus ® and benchmarked against data available in the literature. Also, the process model of chemical solvent scrubbing using monoethanolamine (MEA) was adapted from previous studies. Base-load analysis of the 580 MW el CFPP retrofits revealed that if novel CAP retrofit configurations were employed, in which a new auxiliary steam turbine was coupled with the boiler feedwater pump for extracted steam pressure control, the net efficiency penalty was 8.7–8.8% points. This was close to the 9.5% points in the MEA retrofit scenario. Conversely, CaL retrofit resulted in a net efficiency penalty of 6.7–7.9% points, depending on the fuel used in the calciner. Importantly, when the optimised supercritical CO 2 cycle was used instead of the steam cycle for heat recovery, this figure was reduced to 5.8% points. Considering part-load operation of the 660 MW el CFPP and uncertainty in the process model inputs, the most probable net efficiency penalties of the CaL and MEA retrofits were 9.5% and 11.5% points, respectively. Importantly, in the CaL retrofit scenarios, the net power output was found to be around 40% higher than that of the CFPP without CO 2 capture and double than that for the MEA retrofit scenario. Such performance of the CaL retrofit scenario led to higher profit than that of the 660 MW el CFPP without CO 2 capture, especially if its inherent energy storage capability was utilised. Hence, this study revealed that CaL has the potential to significantly reduce the efficiency and economic penalties associated with mature CO 2 capture technologies.
and other inert gases, is then emitted to the atmosphere having been passed through a heat exchanger to extract as much heat as possible from the exhaust gases; thereby maximising the cycle efﬁ- ciency. The gasiﬁcation process is regulated by water-cooling via (a water-side) heat exchanger. This water then evaporates to form steam, which is used to drive a second, steam driven turbine that generates additional electricity. When this steam leaves the turbine it is condensed before being reheated from the exhaust heat exchanger. This method is believed to be able to provide efﬁciencies of over 46%; some 14% higher than many of the currently operating non-CCS coalpower stations in the UK (Dr. Mike Farley, formerly of Doosan Babcock Energy, private communication, 2008). This tech- nology is quite attractive, because of its relatively high efﬁciency and versatility in terms of fuel use - it could burn either natural gas or hydrogen should the situation arise, or technology advances to enable a partial reﬁt of the IGCC system. The main disadvantage of this technology presently is the high capital cost of the hardware, as well as operational costs  .
seal leakage, deterioration of heat absorption characteristics of basket elements due to fouling or plugging. When the rotor rotates, air leakages may exist, e.g., entrained leakage. Air leakage consumes extra energy from the fan in the boiler system and decreases the heat exchange efficiency of the air preheater . B.J. Drobnic  analyzed the leakage flow through different leak paths; he showed that the leak path from the cool air to the hot flue gas exerted the most significant effect on the heat transfer efficiency. A method for calculating the mass flows of gas through the seals was also introduced , and an adjusting method to reduce the seal clearances in radial seals was further presented . Gromovyk and Ivanik  determined the thermal stresses and displacements that occur in an elastic hollow ceramic circular cylinder when convective heat exchange occurs.
FMEA is to develop, evaluate and enhance the design development and testing methodologies to achieve the elimination of failures and thus obtain world-class competitive products. The main advantages of using FMEA methods are: Reduction of Costs, with a critical impact on warranty returns; Reduction of the Time needed from the project phase to the market launch and Improvement of the Quality and Reliability of the products, while increasing the safety of their operation (Sharma & Srivastava, 2016).
transformed and transported and cause considerable damage hundreds of kilometres away from the source. So local, European wide and hemispheric modelling is required. As a next step within the IPA, concentration-response models are used to derive physical impacts on the basis of the population data and concentration levels of air pollutants. The concentration -response models have been compiled and critically reviewed in ExternE by expert groups (Torfs et al. 2007).
The carbon dioxide level in the atmosphere is considered as a main environmental problem to be solved immediately. This level of carbon dioxide in the atmosphere has been increased at a tremendous pace for last decades . Since carbon dioxide is the most powerful greenhous e gas , it causes global warming and subsequent rise in atmospheric temperature. Average global temperature is raised from14.25°C in 2000 to 14.6°C in 2010 .
The United Nations Environment Programme (UNEP) Governing Council (GC) initiated global assessment of mercury at its twenty-first session held in 2001. Key findings of the global assessment were: (1) mercury is persistent, (2) undergoes long-range transport, and (3) cycles globally. The findings were acknowledged as giving sufficient evidence of adverse global impacts to warrant international action and the GC endorsed the need for global action in 2003. This GC decision resulted in formation of the UNEP Mercury Programme. At its twenty-fifth session, in 2009, the GC decided on a number of matters that will influence the future path of global work on mercury. In particular, the GC decided to prepare a global legally binding instrument on mercury to be completed prior to the twenty-seventh regular session of the GC, which will take place in 2013. The negotiation of the global instrument on mercury has commenced in 2010. To inform the work of the intergovernmental negotiating committee developing the instrument, a study on various types of mercury-emitting sources and current and future trends of mercury emissions, including analyzing and assessing the cost and effectiveness of alternative mercury control technologies and measures (the paragraph 29-study) was called for by the GC. The information in this POG describing various mercury control options from sources utilizing coal combustion for electricity generation has been fed into the paragraph-29 study.