8,818 research outputs found
Decision support for firm performance by real options analytics
This paper develops a real options decision support tool for raising the performance of the firm. It shows how entrepreneurs can use our intuitive tool quickly to assess the nature and type of action required for improved performance. This exploits our estimated econometric relationship between precipitators of entrepreneurial opportunities, time until exercise, and firm performance. Our 3D chromaticity plots show how staging investments, investment time, and firm performance support entrepreneurial decisions to embed, or to expedite, investments. Speedy entrepreneurial action is securely supported with this tool, without expertise in econometric estimation or in formulae for real options valuation
Inward electrostatic precipitation of interplanetary particles
An inward precipitator collects particles initially dispersed in a gas throughout either a cylindrical or spherical chamber onto a small central planchet. The instrument is effective for particle diameters greater than about 1 µm. One use is the collection of interplanetary dust particles which are stopped in a noble gas (xenon) by drag and ablation after perforating the wall of a thin-walled spacecraft-mounted chamber. First, the particles are positively charged for several seconds by the corona production of positive xenon ions from inward facing needles placed on the chamber wall. Then an electric field causes the particles to migrate toward the center of the instrument and onto the planchet. The collection time (of the order of hours for a 1 m radius spherical chamber) is greatly reduced by the use of optimally located screens which reapportion the electric field. Some of the electric field lines terminate on the wires of the screens so a fraction of the total number of particles in the chamber is lost. The operation of the instrument is demonstrated by experiments which show the migration of carbon soot particles with radius of approximately 1 µm in a 5-cm-diam cylindrical chamber with a single field enhancing screen toward a 3.2 mm central collection rod
Material handling systems for the fluidized-bed combustion boiler at Rivesville, West Virginia
The 300,000 lbs/hr steam capacity multicell fluidized-bed boiler (MFB) utilizes complex material handling systems. The material handling systems can be divided into the following areas: (1) coal preparation; transfer and delivery, (2) limestone handling system, (3) fly-ash removal and (4) bed material handling system. Each of the above systems are described in detail and some of the potential problem areas are discussed. A major potential problem that exists is the coal drying system. The coal dryer is designed to use 600 F preheated combustion air as drying medium and the dryer effluent is designed to enter a hot electrostatic precipitator (730 F) after passage through a cyclone. Other problem areas to be discussed include the steam generator coal and limestone feed system which may have operating difficulties with wet coal and/or coal fines
Study of Space Cabin Atmospheres Status Report, 1 Jan. - 30 Jun. 1966
Performance characteristics of aerosol generator, and distribution sampling errors of electrostatic precipitator sampling device for space cabin atmospher
Fine and ultrafine particle number and size measurements from industrial combustion processes : primary emissions field data
This study is to our knowledge the first to present the results of on-line measurements of residual nanoparticle numbers downstream of the flue gas treatment systems of a wide variety of medium- and large-scale industrial installations. Where available, a semi-quantitative elemental composition of the sampled particles is carried out using a Scanning Electron Microscope coupled with an Energy Dispersive Spectrometer (SEM-EDS). The semi-quantitative elemental composition as a function of the particle size is presented. EU's Best Available Technology documents (BAT) show removal efficiencies of Electrostatic Precipitator (ESP) and bag filter dedusting systems exceeding 99% when expressed in terms of weight. Their efficiency decreases slightly for particles smaller than 1 mu m but when expressed in terms of weight, still exceeds 99% for bag filters and 96% for ESP. This study reveals that in terms of particle numbers, residual nanoparticles (NP) leaving the dedusting systems dominate by several orders of magnitude. In terms of weight, all installations respect their emission limit values and the contribution of NP to weight concentrations is negligible, despite their dominance in terms of numbers. Current World Health Organisation regulations are expressed in terms of PM2.5 wt concentrations and therefore do not reflect the presence or absence of a high number of NP. This study suggests that research is needed on possible additional guidelines related to NP given their possible toxicity and high potential to easily enter the blood stream when inhaled by humans
A cost-benefit analysis of a pellet boiler with electrostatic precipitator versus conventional biomass technology: A case study of an institutional boiler in Syracuse, New York
BACKGROUND: Biomass facilities have received increasing attention as a strategy to increase the use of renewable fuels and decrease greenhouse gas emissions from the electric generation and heating sectors, but these facilities can potentially increase local air pollution and associated health effects. Comparing the economic costs and public health benefits of alternative biomass fuel, heating technology, and pollution control technology options provides decision-makers with the necessary information to make optimal choices in a given location.
METHODS: For a case study of a combined heat and power biomass facility in Syracuse, New York, we used stack testing to estimate emissions of fine particulate matter (PM2.5) for both the deployed technology (staged combustion pellet boiler with an electrostatic precipitator) and a conventional alternative (wood chip stoker boiler with a multicyclone). We used the atmospheric dispersion model AERMOD to calculate the contribution of either fuel-technology configuration to ambient primary PM2.5 in a 10 km x 10 km region surrounding the facility, and we quantified the incremental contribution to population mortality and morbidity. We assigned economic values to health outcomes and compared the health benefits of the lower-emitting technology with the incremental costs.
RESULTS: In total, the incremental annualized cost of the lower-emitting pellet boiler was 1.7 million annually, greatly exceeding the differential costs even when accounting for uncertainties. Our analyses also showed complex spatial patterns of health benefits given non-uniform age distributions and air pollution levels.
CONCLUSIONS: The incremental investment in a lower-emitting staged combustion pellet boiler with an electrostatic precipitator was well justified by the population health improvements over the conventional wood chip technology with a multicyclone, even given the focus on only primary PM2.5 within a small spatial domain. Our analytical framework could be generalized to other settings to inform optimal strategies for proposed new facilities or populations.This research was supported by the New York State Energy Research and Development Authority (NYSERDA), via an award to the Northeast States for Coordinated Air Use Management (Agreement #92229). The SCICHEM work of KMZ was supported by the Electric Power Research Institute (EPRI)
Monitoring of Heavy Metals By Energy Dispersive X-Ray Fluorescence Spectrometry
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Fundamentals and salient features of a projected heavy metals monitoring system are discussed. Determination of mass concentrations is achieved by using a new dust emission monitor, consisting of a "Zero Pressure Probe" for isokinetic sampling, which is connected to a "Longitudinally Oscillating Band" mass detector. The thin dust layer, precipitated on the surface of heat resistant filter tapes could be analysed nondestructively by energy-dispersive X-ray fluorescence (EDXRF). Using a small portable EDXRF-system with radioisotope-excitation, quasi-continuous monitoring of particulate heavy metals (Cd, Hg, Pb, Cu, Sb, Zn, Sn) suspended in incinerator stack gases is expected to be feasible. Another application of EDXRF-analysis is the reported investigation of electrostatic precipitator ash (ESP-fly ash). Using the "Linear Multi-Elemental-Standard Addition Method" as a fast and simple routine technique, results are reported for the concentrations of Pb, Cd, Cu and Zn in fly ash samples which had been collected in different fields (hoppers) of the electrostatic precipitator
Optimization of the flue gas-flow controlling devices of the electrostatic precipitator of unit A4 in TPP "Nikola Tesla"
Homogeneity of the flue gas-flow through the chamber of an electrostatic precipitator is one of the basic influencing parameter on dedusting efficiency. This paper presents results of a multiobjective optimization study of the flue gas controlling devices of electrostatic precipitator of 324 MWe lignite fired Unit A4 of TPP "Nikola Tesla" in Serbia. The aim was to achieve better flow homogeneity in the cross-section of the precipitator compared to the original design. Additional constraints were to maintain the minimum as possible overall weight of the proposed design as well as pressure drop through the precipitator. Numerical simulations based on CFD were used to investigate dependence of the velocity distribution in the ducts and precipitator’s chamber with respect to the geometrical parameters of tested concepts of turning blades. A series of 22 detailed full-scale numerical models of the precipitator with different concepts of turning vanes designs were developed. Assessment of the flow field uniformity for each tested design was performed based on the analysis of several homogeneity parameters calculated for selected vertical cross-sections of the precipitator. After the reconstruction according to optimized design, results of measurements confirmed significant improvements of the velocity distribution in the vertical cross-sections of the precipitator, increase of dedusting efficiency and reduction of PM emission
Development of methods for preparing fly ash for separation by activation
Purpose. Isolation of the aluminosilicate fraction from fly ash, study of
physical and mechanical properties of binders obtained from TPP wastes.
Methods. Ash, carbon concentrate (underburn), ash concentrate and
products of their treatment with reagents were tested by optical methods.
The morphology of the particles of the subjects of inquiry was studied with
the scanning electron microscope REM-100. The composition of the ash
phases was investigated using the X-ray diffractometer DRON-2.
Findings. The technology of sorbents based on coal combustion
products through a variety of methods was researched. It is shown that these
sorbents are distinctive because their structure has non-localized pi-electrons
of the graphite-like networks of crystallites of carbon. This circumstance
determines not only the uniqueness of electro-physical properties of coal but
also adsorption, redox, chemisorption processes on the border of coalslurry.
The listed circumstances allow you to use the original methods of
chemical and mechanochemical modification of the surface chemical and
coal, due to introducing desired donor and acceptor atoms in carbon frame,
which increases the absorption capacity and selectivity carbon sorbents.
Practical implications. The article presents the results of receipt of
binders based on TPP ash. It has been shown that a component of the fly ash
is aluminosilicate spheres that can be used in the production of lightweight
concrete. It is proved that the result of mechanochemical activation mixture
consisting of alumino-silicates, resulting lightweight concrete has high
strength 7-8 MPa, which allows, while maintaining the technical
characteristics save from 20 to 30 % of binder. Concrete obtained based on
aluminosilicate spheres separated from fly ash may be used to prepare the outer wall construction, small building blocks, as well as monolithic
housing. In comparison with known compositions keramsit compositions
comprising TPP waste
Estimation of Marginal Abatement Cost of Air Pollution in Durgapur City of West Bengal
Air pollution in industrial cities with emissions from firms is a growing problem in India. Durgapur, one of the growing industrial cities in eastern India, covering a host of industries, suffers from similar problems. The paper estimates the marginal abatement cost of air pollution of industries in Durgapur, West Bengal. We model the technology of a firm with output-distance function. Here the linear programming approach is adopted to estimate the shadow prices and distance values. Results reveal that there is a wide variation in shadow prices of Suspended Particulate Matter and distance values between firms under particular category of industries thus indicating the variability in the degree of compliance, use of resources and the vintages of capital. In this context the paper suggests policies for air quality management in urban industrial areas of West Bengal which will help to achieve sustainable industrial development.Output Distance Function, Shadow Prices, Distance Values
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