Cold DeNOx development for oxyfuel power plants

Flue gas purification is a necessary method to avoid emission of sour gases like SO_x and NO_x into the environment. Another important aspect is the zero CO₂ emission from coal-fired power plants. Oxyfuel technology is one of the processes to reach this goal. LINDE KCA Dresden in cooperation with Vattenfall Europe is operating a pilot plant producing liquefied CO₂. Product specification and material requirements make flue gas purification for the removal of SO_x and NO_x unavoidable. The new oxyfuel technologies offer new process conditions for flue gas purification which are not available at atmospheric conditions.At Linde laboratories, catalytic and non-catalytic DeNOx and DeSOx processes have been screened for oxyfuel application. After first feasibility studies, laboratory experiments and economic evaluations, it was decided to develop a process based on wet scrubber systems to remove NO_x from flue gas, simultaneously producing ammonia nitrites which can be thermally decomposed into nitrogen in a second step. After demonstration of the single process steps on laboratory scale, a pilot scrubber was erected and commissioned in 2010 at Schwarze Pumpe Oxyfuel Pilot Plant. In September 2010, the successful completion of the pilot tests demonstrated the NO_x removal efficiency of this technology. The data from the pilot plant tests have been used to finalise a kinetic model describing the NO_x absorption behaviour regarding NO_x removal rate and nitrite selectivity for demonstration of plant scale up. This DeNOx-process is now marketed under the name “LICONOX”.     

Health benefits valuation of regulatory intervention for air pollution control in thermal power plants in Delhi,India

This study estimates minimum marginal health benefits (morbidity reduction only) of air pollution control and total health benefits arising from regulatory intervention regarding the adoption of the World Bank emission guidelines (WBEG) for thermal power plants (TPPs) in Delhi. The Industrial Source Complex-Short-Term Version–3 (ISCST3) model has been used to estimate the contribution to air pollution from TPPs. The household health production function (avertive behaviour) has been used to value health benefits of air pollution control. The study revealed that the ambient air pollution due to TPPs is reduced by between 62.17% to 83.45% by adopting the WBEG. Annual marginal benefit due to reduction in exposure to air pollution by 1 μg m^?3 is estimated to be US$0.353 per person. Total annual health benefits for adopting the WBEG for TPPs are estimated at US$235.19 million. This study provides a novel methodology to evaluate health benefits of regulatory intervention.     

A geostatistical and probabilistic spectral image processing methodology for monitoring potential CO2 leakages on the surface

Remote sensing has demonstrated success in various environmental applications over the past three decades. This is largely attributed to its ability for good areal coverage and continued development in sensor technologies. Carbon dioxide Capture and Storage (CCS) is an emerging climate change mitigation technology where monitoring is vital for its sustainability. This research investigates the use of spectral remote sensing imagery in detecting potential CO₂ occurrences at the surface, should a leakage occur from subsurface reservoirs where CO₂ is stored. Currently, there are no known leakages of CO₂ at industrial storage sites, therefore, this research was carried out at the Latera natural analogue site in Italy, in order to develop the methodology described. This paper describes the use of a popular probabilistic information fusion theory, referred to as the Dempster–Shafer theory of evidence, to analyse outlier pixels (anomalies). Outlier pixels are first determined using a new geostatistical image filtering methodology based on Intrinsic Random Function (IRF), Independent Component Analysis (ICA), and the industry standard parametric Reed–Xiaoli (RX) anomaly detection. Information fusion of detected outlier pixels and indirect surface effects of CO₂ leakage over time, such as stressed vegetation or mineral alterations, assigns a confidence measure per outlier pixel in order to identify potential leakage points. After visual validation using direct field measurements, it was demonstrated that the proposed methodology is able to detect majority of the seepage points at Latera, and holds promise as a new unsupervised CO₂ monitoring methodology.     

Strategies for emission reduction from thermal power plants

Major polluters of man's environment are thermal power stations (TPS) and power plants, which discharge into the atmosphere the basic product of carbon fuel combustion, CO2, which results in a build-up of the greenhouse effect and global warm-up of our planet's climate. This paper is intended to show that the way to attain environmental safety of the TPS and to abide by the decisions of the Kyoto Protocol lies in raising the efficiency of the heat power stations and reducing their fuel consumption by using nonconventional thermal cycles. Certain equations have been derived to define the quantitative interrelationship between the growth of efficiency of the TPS, decrease in fuel consumption and reduction of discharge of dust, fuel combustion gases, and heat into the environment. New ideas and new technological approaches that result in raising the efficiency of the TPS are briefly covered: magneto-hydrodynamic resonance, the Kalina cycle, and utilizing the ambient heat by using, as the working medium, low-boiling substances.     

Simulation of cooling-water discharges from power plants

Accurate simulation of the temperature distribution in a cooling lake or reservoir is often required for feasibility studies of engineering options that increase the cooling capacity of the waterbody. A three-dimensional hydrodynamic and temperature model has been developed and applied to several cooling lakes in the south-eastern United States. In this paper, the details of the modeling system are presented, along with the application to the Flint Creek Lake.     

Integration of CO2 capture unit using single- and blended-amines into supercritical coal-fired power plants: Implications for emission and energy management

This work provides the essential information and approaches for integration of carbon dioxide (CO₂) capture units into power plants, particularly the supercritical type, so that energy utilization and CO₂ emissions can be well managed in the subject power plants. An in-house model, developed at the University of Regina, Canada, was successfully used for simulating a 500 MW supercritical coal-fired power plant with a post-combustion CO₂ capture unit. The simulations enabled sensitivity and parametric study of the net efficiency of the power plant, the coal consumption rate, and the amounts of CO₂ captured and avoided. The parameters of interest include CO₂ capture efficiency, type of coal, flue gas delivery scheme, type of amine used in the capture unit, and steam pressure supplied to the capture unit for solvent regeneration. The results show that the advancement of MEA-based CO₂ capture units through uses of blended monoethanolamine–methyldiethanolamine (MEA–MDEA) and split flow configuration can potentially make the integration of power plant and CO₂ capture unit less energy intensive. Despite the increase in energy penalty, it may be worth capturing CO₂ at a higher efficiency to achieve greater CO₂ emissions avoided. The flue gas delivery scheme and the steam pressure drawn from the power plant to the CO₂ capture unit should be considered for process integration.     

Risk assessment for selected xenobiotics by bioassay methods with higher plants

Different bioassays with higher plants were approved for use in a bioassay procedure for testing of xenobiotics according to the German Chemicals Act. Selected environmental pollutants (atrazine, cadmium chloride, 2,6-dichlorobenzonitrile, pentachlorophenol, potassium dichromate, thiourea), all from a list of reference chemicals, were tested with these methods. Dose-response curves for growth of oats and turnips were evaluated in soil and vermiculite (nonsorptive substrate), and availability to plants was calculated by comparing the EC₅₀ values for one chemical in both substrates. The most active chemical was atrazine, followed by 2,6-dichlorobenzonitrile, pentachlorophenol, potassium dichromate, cadmium chloride, and thiourea. The least available compound to plants was pentachlorophenol, tested with turnips (Brassica rapa var.rapa). The strongest inhibition of germination, demonstrated in an in vitro assay with garden cress (Lepidium sativum), was found with 2,6-dichlorobenzonitrile, the lowest with atrazine. The effect of an extended exposure of the plants to the chemicals was evaluated in a long-term bioassay with oats (Avena sativa) in hydroponic culture. Several dose-response curves during the growing period were derived. It was found that the EC₅₀ values for atrazine and thiourea decreased markedly during the first four weeks; thereafter the changes were much smaller. As an overall conclusion, a bioassay procedure is proposed that can be included in the graduated plan recommended by the German Chemicals Act.     

Evaluation of methods for determining adverse impacts of air pollution on terrestrial ecosystems

Methods used to determine adverse impacts of air pollution on four levels of biological organization of terrestrial ecosystems were evaluated for their use in decision making by federal land managers of class I areas and as guidelines for scientists employed to design field studies in these areas. At the level of the individual, visible injury, biomass, and sulfur uptake were the most often used components; at the population level, natality and mortality; at the community level, diversity; and at the ecosystem level, biogeochemical cycling. Most studies focused on structural responses of individual organisms. These components are relatively sensitive and are easy and inexpensive to measure; however, linkages of these parameters to adverse impacts on populations, communities, or ecosystems are lacking. Measurements of effects of air pollution at the higher levels of organization are confounded by natural variability, long response times, climatic variation, pathogens, and other factors. In addition, the lack of replication and of true control areas creates severe problems for design of monitoring programs and testing of hypotheses concerning effects.     

Review of the methods used for isolating pharmaceutical lead compounds from traditional medicinal plants

The possibility of finding new medicines from natural sources is one of the more commonly cited reasons for preserving biodiversity, and employing indigenous knowledge of traditional healing remedies greatly increases the likelihood of discovering these hidden medicinal compounds. The main difficulties in using natural products as a source for pharmaceutical lead compounds involve separating the plethora of compounds from the original extract, as well as the gamble of time and money invested in an activity that may not yield a novel compound. However, while these difficulties exist, the potential of natural products still far outweighs the limitations of the simple structures and known modes of action of synthetic lead compounds. As such, the production of novel medicines, particularly for cancer and human immunodeficiency virus (HIV) treatments as well as the inhibition of antibiotic-resistant bacteria, now requires the utilization of natural products. This paper provides a review of the current methods used in elucidating pharmaceutical lead compounds from natural sources, focusing on plant samples in particular.     

All-Sky brightness monitoring of light pollution with astronomical methods

This paper describes a mobile prototype and a protocol to measure light pollution based on astronomical methods. The prototype takes three all-sky images using BVR filters of the Johnson-Cousins astronomical photometric system. The stars are then identified in the images of the Hipparcos and General Catalogue of Photometric Data II astronomical catalogues, and are used as calibration sources. This method permits the measurement of night-sky brightness and facilitates an estimate of which fraction is due to the light up-scattered in the atmosphere by a wide variety of man-made sources. This is achieved by our software, which compares the sky background flux to that of many stars of known brightness. The reduced weight and dimensions of the prototype allow the user to make measurements from virtually any location. This prototype is capable of measuring the sky distribution of light pollution, and also provides an accurate estimate of the background flux at each photometric band.     

Comparison of air quality in the UK and Russia

Summary A comparison is made of some of the key elements of ambient air quality in the UK and the Russian Federation. In each country air quality has recently moved towards the top of public environmental concerns. The legislative and regulatory framework for controlling/improving air quality is considered briefly. In the Russian Federation ambient air ground level standards exist for over 20 chemicals. In contrast, in the UK, to date, only four EEC (European Union) imposed standards are in operation. The Russian standards are considerably stricter than those of the UK, but compliance in many cities is very poor. In each country air quality has benefited more from economic recessionary forces than direct government action. In both countries the trend is to a reduction in sulphur dioxide levels. In contrast, nitrogen dioxide levels are increasing primarily because of growing road traffic levels. An attempt is made to compare air quality in Moscow with that in London. Constraints include the use of different methodologies and forms of data presentation. However, the overall impression is of substantial similarities in the air quality of the two capital cities.     

Study of boron behaviour in two Spanish coal combustion power plants

A full-scale field study was carried out at two Spanish coal-fired power plants equipped with electrostatic precipitator (ESP) and wet flue gas desulfurisation (FGD) systems to investigate the distribution of boron in coals, solid by-products, wastewater streams and flue gases. The results were obtained from the simultaneous sampling of solid, liquid and gaseous streams and their subsequent analysis in two different laboratories for purposes of comparison. Although the final aim of this study was to evaluate the partitioning of boron in a (co-)combustion power plant, special attention was paid to the analytical procedure for boron determination. A sample preparation procedure was optimised for coal and combustion by-products to overcome some specific shortcomings of the currently used acid digestion methods. In addition boron mass balances and removal efficiencies in ESP and FGD devices were calculated. Mass balance closures between 83 and 149% were obtained. During coal combustion, 95% of the incoming boron was collected in the fly ashes. The use of petroleum coke as co-combustible produced a decrease in the removal efficiency of the ESP (87%). Nevertheless, more than 90% of the remaining gaseous boron was eliminated via the FGD in the wastewater discharged from the scrubber, thereby causing environmental problems.     

An evaluation of four key methods for monitoring household waste prevention campaigns in the UK

Household waste prevention in England has been recognised in national strategy as a key component for future sustainable practice. To support the policy agenda, the Department of Environment, Food and Rural Affairs (Defra) in England has funded an extensive programme of fundamental research in the area. The specific research aim reported on here, in this Defra funded project, was to trial and assess methods for monitoring and evaluating approaches detailed in the National Resource and Waste Forum (NRWF)’s Household Waste Prevention Toolkit. The methods that formed the basis for the four research Objectives for the project were: using pilot and control areas (core Objective), tracking waste arisings, measuring specific activities and declared awareness and behaviour surveys. A primary objective of this research was to quantify the direct waste tonnage impacts of implementing a targeted household waste campaign in Dorset County, UK. A key performance indicator chosen for this assessment was the weight of waste collected at the kerbside from households. In an area where a waste prevention campaign is well planned and implemented then reductions in household waste arisings in pilot areas can be in the region of 2% per annum. This method for monitoring can be used, in the hands of an expert project team, to communicate to the public the direct benefits of waste prevention. It was found that there are a wide range of factors that need to be taken into account in the UK, and that these had hitherto been given little prominence, such as careful matching of pilot and control areas – this proved problematical in this research. However, a range of techniques used to support the methods, e.g. doorstepping surveys and focus groups could not show clear attributable waste prevention impacts but their findings could be used to direct new future messages to the public. The most successful and measurable campaign activities that were revealed by evaluation were: mail preference registrations, Home composting and doorstepping. An expert evaluation of all major methods found that no clear preference was revealed as to which were the most useful. None of the methods were judged very poor neither very good, all had major issues about their use. Tracking waste arisings and focus groups were assessed to be the best techniques in terms of input effort to output value. It is likely that waste prevention teams for household waste will need very careful training in the cost-effective use of the NRWF Toolkit before they are competent to apply it to a given place; the issues are more complex than were first thought.     

核潜艇内空气龄的计算方法探讨

介绍空气龄的两种计算方法及其基本原理,比较了示踪气体测试法和CFD方法的适用范围及优缺点,考虑到核潜艇特殊密闭空间的空气品质的重要性,针对核潜艇的特殊情况,提出了计算空气龄的方法。     

Life cycle assessment of carbon dioxide capture and storage from lignite power plants

In this article, we present a life cycle assessment (LCA) of CO₂ capture and storage (CCS) for several lignite power plant technologies. The LCA includes post-combustion, pre-combustion and oxyfuel capture processes as well as subsequent pipeline transport and storage of the separated CO₂ in a depleted gas field.The results show an increase in cumulative energy demand and a substantial decrease in greenhouse gas (GHG) emissions for all CO₂ capture approaches in comparison with power plants without CCS, assuming negligible leakage within the time horizon under consideration. Leakage will, however, not be zero. Due to the energy penalty, CCS leads to additional production of CO₂. However, the CO₂ emissions occur at a much lower rate and are significantly delayed, thus leading to different, and most likely smaller, impacts compared to the no-sequestration case. In addition, a certain share of the CO₂ will be captured permanently due to chemical reactions and physical trapping.For other environmental impact categories, the results depend strongly on the chosen technology and the details of the process. The post-combustion approach, which is closest to commercial application, leads to sharp increases in many categories of impacts, with the impacts in only one category, acidification, reduced. In comparison with a conventional power plant, the pre-combustion approach results in decreased impact in all categories. This is mainly due to the different power generation process (IGCC) which is coupled with the pre-combustion technology.In the case of the oxyfuel approach, the outcome of the LCA depends highly on two uncertain parameters: the energy demand for air separation and the feasibility of co-capture of pollutants other than CO₂. If co-capture were possible, oxyfuel could lead to a near-zero emission power plant.     

Application of an entropy-based Bayesian optimization technique to the redesign of an existing monitoring network for single air pollutants

We apply the entropy-based Bayesian optimizing approach of Le and Zidek to the spatial redesign of the extensive air pollution monitoring network operated by Metro Vancouver, in the Lower Fraser Valley, British Columbia. This method is chosen because of its statistical sophistication, relative to other possible approaches, and because of the very rich, two-decade long data record available from this network. The redesign analysis is applied to ozone, carbon monoxide and PM_2.5 pollutants.     

Exploring the potential for improvement of the energy performance of coal fired power plants with post-combustion capture of carbon dioxide

The application of post-combustion capture (PCC) processes in coal fired power stations can result in large reductions of the CO₂-emissions, but the consequential decrease in generation efficiency is an important draw-back. The leading PCC technology is based on chemical absorption processes as this technology is the one whose scale-up status is closest to full-scale capture in power plants. The energy performance of this process is analysed in this contribution. The analysis shows that the potential for improvement of the energy performance is quite large. It is demonstrated that further development of the capture technology and the power plant technology can lead to generation efficiencies for power plants with 90% CO₂ capture which are equivalent to the current generation efficiencies without CO₂ capture, i.e. 0.4 (HHV), leading to an additional resource consumption of 16%. These improvements are possible throughout a combined improvement for the capture process and power generation processes.     

The health and visibility cost of air pollution: a comparison of estimation methods

Air pollution from motor vehicles, electricity-generating plants, industry, and other sources can harm human health, injure crops and forests, damage building materials, and impair visibility. Economists sometimes analyze the social cost of these impacts, in order to illuminate tradeoffs, compare alternatives, and promote efficient use of scarce resource. In this paper, we compare estimates of the health and visibility costs of air pollution derived from a meta-hedonic price analysis, with an estimate of health costs derived from a damage-function analysis and an estimate of the visibility cost derived from contingent valuation. We find that the meta-hedonic price analysis produces an estimate of the health cost that lies at the low end of the range of damage-function estimates. This is consistent with hypotheses that on the one hand, hedonic price analysis does not capture all of the health costs of air pollution (because individuals may not be fully informed about all of the health effects), and that on the other hand, the value of mortality used in the high-end damage function estimates is too high. The analysis of the visibility cost of air pollution derived from a meta-hedonic price analysis produces an estimate that is essentially identical to an independent estimate based on contingent valuation. This close agreement lends some credence to the estimates. We then apply the meta hedonic-price model to estimate the visibility cost per kilogram of motor vehicle emissions.     

Impact of industrial air pollutants on some biochemical parameters and yield in wheat and mustard plants

The present study was carried out to determine the impacts of SO₂, NO _x , SPM and RSPM, the most common air pollutants, generated mainly due to industries and vehicles, on some biochemical parameters and yield in wheat and mustard plants during 2006. The concentration of SO₂, NO _x , SPM and RSPM was determined at the polluted sites across the seasons, which ranged between 14.29–18.10, 20.81–22.43, 483.65–500.85 and 160.67–171.18 μg m⁻³, respectively. The wheat and mustard plants grown at polluted sites showed significant reduction in chlorophyll ‘a’, chlorophyll ‘b’, total chlorophyll, carotenoid, ascorbic acid, pH, relative water content and yield. The data were further analyzed using a two way ANOVA. It is concluded that the ambient air pollutants have a potential adverse impact on biochemical parameters, which further leads to a reduction in the yield of wheat and mustard crops.