Power Plant Stack Research Articles

Impact of fluidized bed combustion waste on metal content of crops and soil

The fluidized bed combustion process for removing SO2 from coal-fired power plant stack gases results in generation of large tonnages of waste requiring environmentally acceptable storage or disposal. A field study was initiated in fall 1985 to determine limits of fluidized bed combustion waste (FBCW) applications to agronomic crops without causing significant yield reduction or accumulation of heavy metals in plants or the soil. Rates of FBW ranging from 22 to 560 t ha−1 were incorporated in soil by plowing down single and split applications. Conventional agricultural lime treatments were included for comparison. Tall fescue (Festuca arundinacea), alfalfa (Medicago sativa L.), corn (Zea mays L.), and soybeans (Glycine max. L.) were grown from 1986–88. Annual applications of 22 t ha−1 did not affect yield or metal uptake of any test crop. A single 112 t ha−1 application had no adverse effect, but repeated applications of that rate lowered corn and soybean yields. The rate of 560 t ha−1 resulted in depressed or eliminated growth of all crops. A high pH and high concentrations of Ca and S were associated with this rate but heavy metals and B concentrations in soil and plant tissue were not significantly affected.

Design of monolith catalysts for power plant nitrogen oxide (No.+-.) emission control

A mathematical model was developed to describe the reduction of NO with NH 3 in simulated power plant stack gases, over the internal surfaces of monolith-shaped catalysts of the vanadia-titania type. The model indicated that up to 50% improvement in the volumetric activity of these catalysts would be possible if they could be prepared with the computed optimum pore structure

A study of the energetics and economics of microalgal mass culture with the marine chlorophyte Tetraselmis suecica: Implications for use of power plant stack gases

The marine phytoplankter Tetraselmis suecica was grown in shallow outdoor flumes for a period of approximately 6 months at the Natural Energy Laboratory of Hawaii. In full sunlight, gross production rates were 15-20 g C m(-2) d(-1). The corresponding photosynthetic efficiencies (PE's) were 9-10%. Respiration losses removed about half the gross production. The CO(2) utilization efficiencies of 96 +/- 11% were achieved by bubbling CO(2) into the culture with the use of a counterflow sump system. Adding the CO(2) in the form of carbonated water resulted in utilization efficiencies of 81 +/- 11%. Archimedes screws proved superior to both paddle wheels and propellers as a means of circulating the water in the flumes. Insertion of foil arrays into the flumes to effect systematic mixing of the culture significantly enhanced production. The enhancement was greater when the foils were oriented at a small angle relative to the horizontal than when they were oriented at the same angle relative to the vertical. Light modulation effects are implicated as the probable cause of most of the enhancement. Substitution of electric power plant stack gases for pure CO(2) resulted in no significant change in the production of T. suecica grown in chemostat culture.

Meteorological Data Needs for Modeling Air Quality Uncertainties

A probabilistic framework for incorporating uncertainty in air quality models is described. The quantitative dependence of the uncertainty in calculated air quality concentrations on the uncertainty in the input meteorological data is illustrated using a simple Second-order Closure integrated Model Plume in combination with the EPRI Plume Model Validation and Development Data Set. Evaluation of the model results demonstrate that even though individual hourly samples cannot be deterministically predicted downwind of a powerplant stack, statistical representations of the observed cumulative distribution of the sample values are quite predictable. We discuss the data needed to improve the definition of the range of meteorological uncertainty within an ensemble of flows defined by given meteorological data, and thus provide for improvements in predictability models of the type illustrated. We argue that attempts to collect the data needed to define more precisely the variance within the ensemble of compatible flows will prove more productive than attempts to eliminate meteorological uncertainties in given datasets.

Computation of Pareto-optimal Reconstruction Sequence of Regionally Distributed Emittants of air Pollution

The “optimal” reconstruction sequence of air pollution emittants (stacks) of electrical power plants is formulated as a multi-criteria decision problem with respect to the reduction of air pollution (that means an investment allocation problem). Using our (model-based) DSS “REH” (Straubel, 1986) one can generate decision compromises by vector optimization representing decision proposals in agreement with the subjective preference of the decision maker (respecting to the different non-cooperative objectives).

Vapor-phase concentrations of arsenic, selenium, bromine, iodine, and mercury in the stack of a coal-fired power plant

A sampling and analysis procedure is described for determining vapor-phase concentrations of As, Se, Br, I, and Hg in the stack of a coal-fired power plant. The percentages of the total in-stack concentrations for these elements present in the vapor phase are as follows: Br, 98%; Hg, 98%; Se, 59%; As, 0.7-52%; and I, greater than or equal to99%. A lower limit of 99% was obtained for Cl. The vapor-phase concentration of As appears to be dependent upon the in-stack or filter mass loading. This indicates that a vaporization-condensation mechanism may control the vapor-phase concentrations of As. The result for Se indicate that the efficiency of the electrostatic precipitator affects particle vapor-phase fractionation. The results obtained in this study are compared with previous mass balance calculations.

210Pb in Bioenergy Production

Abstract 210Pb is probably one of the major contributors to the radiation dose received by humans from the fumes emitted from the stacks of power plants using fossil fuels or biofuels. As a first step in the estimation of the total radiological impact on humans of radioactive emissions, we have determined 210Pb radioactivity enrichment factors between fuel and ash products and dose equivalents from 210Pb from stack releases to people living in the surroundings. Radioactivity concentrations in ash, peat, wood and other waste products from forests have been determined in 15 district heating plants, located throughout Sweden, which use bioenergy for hot water production. Dose equivalents to people living close to the plants will be, at most, around a few tens of nSv per year from 210Pb, assuming 1000 Bq.kg-1 in the stack effluent. It was also found that more than 50% of the lead is probably in a volatilised phase, separate from the fly ash, and is therefore not caught in the filters.

Radioecological Measurements in the Coal Power Plant Environment

Radioecological measurements were carried out on the radioactive nuclides escaping from the stacks of coal-fired power plants (CPP) and dispersing into the environment, as most types of lignites burned contain radioactive nuclides, mostly of the uranium series. Different methods were used, such as low level counting, gamma ray spectroscopy, nuclear activation analysis and the delayed neutron technique, TL dosimetry, the solid state nuclear etched track detector technique, WL monitoring and air sampling. The Valley model for atmospheric dispersion of the escaping 226Ra was applied and a series of experimental measurements of this nuclide were carried out in the environment of CPPs for simulation. TLD measurements of the external exposure dose rate as well as radon concentration indoor measurements for a period of three years (1985-1987) are presented.

Radioecological Measurements in the Coal Power Plant Environment

Abstract Radioecological measurements were carried out on the radioactive nuclides escaping from the stacks of coal-fired power plants (CPP) and dispersing into the environment, as most types of lignites burned contain radioactive nuclides, mostly of the uranium series. Different methods were used, such as low level counting, gamma ray spectroscopy, nuclear activation analysis and the delayed neutron technique, TL dosimetry, the solid state nuclear etched track detector technique, WL monitoring and air sampling. The Valley model for atmospheric dispersion of the escaping 226Ra was applied and a series of experimental measurements of this nuclide were carried out in the environment of CPPs for simulation. TLD measurements of the external exposure dose rate as well as radon concentration indoor measurements for a period of three years (1985-1987) are presented.

Comparisons between the metal content of a transplanted lichen before and after the start-up of a coal-fired power station in Israel

The lichen Ramalina duriaei (De Not.) Bagl. was transplanted to 10 biomonitoring sites during the period December 1981 – December 1982. The amounts of Ni, Cr, Cu, Zn, and Pb in the lichen material were measured at the beginning and at the end of the exposure period. These data were compared with the metal amounts detected in R. duriaei transplanted to the same stations during the period February 1979 – March 1980. After the 1981 – 1982 period, the regional amounts of Ni, Cr, and Pb in the transplanted lichen were found to be higher than in the lichen transplanted to the same sites during the 1979–1980 period, prior to the operation of the coal-fired power plant. The increase of Pb in the lichen after the second period (1981 – 1982) reflects the increase in the total number of motor vehicles in the country during that time. The increase of the amounts of Cr and Ni in the latter period is probably related to emissions of these substances from the power-plant stack. The regional decrease in Zn amount in the lichen in the latter period is probably related to a decrease in the use of Zn as a constituent of foliar nutrients in agriculture.

CO 2 Transport: A new application of the assignment problem

The possibility exists that Ohio River Valley coal-burning power plant stack gases rich in CO 2 can be profitably disposed of by transportation via existing reversed flow natural gas trunklines to the Gulf Coast, where they can be sold as an injectant for enhanced oil recovery. Part of the uncertainty arises from the difficulty in identifying, from among the large number of power plants and oil fields which could supply and demand the CO 2, which set would provide maximum profit for the pipeline companies, given the revenues expected from each, the feeder and gathering line construction costs, and the costs of shipment over existing trunklines. The profit-maximizing problem is viewed as a variant of the familiar knapsack problem, where the pipelines are viewed as containers to be filled by portions of differing volume and value per unit volume, transported, and emptied by dividing up their contents into portions of differing volume and value per unit volume. The problem is formulated, and a set of solution techniques examined. A real problem is solved, using a greedy algorithm.

Bulk Sampling - A Tool for Settling Disputes

Millions of tons of coal, ore and other bulk commodities change hands all over the world on a daily basis. Dollar amounts involved are enormous. Financial impact brought on by possible cargo quality discrepancies can be staggering. On what basis are the accounts normally settled and in the event disputes arise, how are they resolved to the satisfaction of everyone concerned? Recently another problem of quite a different nature has emerged. It is the SO, emissions from power plant stacks. With acid rain legislation in serious contention in Washington, potential ominous fines or even the threat of plant shut down will force our coal burning power plants to initiate strict quality control of coal to ensure their adherence to the imposed sulfur limits. Enforcement of these rules will trigger yet another legal battle. How can these plants accurately monitor the quality of the tens of thousands tons of coal fed daily into the boilers? These two problems are quite different in nature.

Boiler Implosion Control in Fossil Fuel Power Plants

An evaluation of systems for control of fossil fuel power plant boiler and stack implosions has been performed using computer simulation techniques described in a companion paper. The simulations have shown that forced and induced draft fan control systems and induced draft fan bypass systems reduce the furnace pressure excursions significantly following a main fuel trip. The limitations of these systems are associated with actuator range and response time and stack pressure excursions during control actions. Preliminary study suggests that an alternative control solution may be achieved by discharging steam into the furnace after a fuel trip.

A quantitative assessment of source contributions to inhalable particulate matter pollution in metropolitan Boston

In this paper, source apportionment techniques are employed to identify and quantify the major particle pollution source classes affecting a monitoring site in metropolitan Boston, MA. A Principal Component Analysis (PCA) of paniculate elemental data allows the estimation of mass contributions for five fine mass panicle source classes (soil, motor vehicle, coal related, oil and salt aerosols), and six coarse panicle source classes (soil, motor vehicle, refuse incineration, residual oil, salt and sulfate aerosols). Also derived are the elemental characteristics of those source aerosols and their contributions to the total recorded elemental concentrations (i.e. an elemental mass balance). These are estimated by applying a new approach to apportioning mass among various PCA source components: the calculation of Absolute Principal Component Scores, and the subsequent regression of daily mass and elemental concentrations on these scores. One advantage of the PCA source apportionment approach developed is that it allows the estimation of mass and source particle characteristics for an unconventional source category: transported (coal combustion related) aerosols. This particle class is estimated to represent a major portion of the aerosol mass, averaging roughly 40 per cent of the fine mass and 25 per cent of the inhalable particle mass at the Watertown, MA site. About 45 per cent of the fine particle sulfur is ascribed to this one component, with only 20 per cent assigned to pollution from local sources. The composition of the coal related aerosol at this site is found to be quite different from particles measured in the stacks of coal-fired power plants. Sulfates were estimated to comprise a much larger percentage of the ambient coal related aerosol than has been measured in stacks, while crustal element percentages were much reduced. This is thought to be due to primary panicle deposition and secondary aerosol accretion experienced during transport. Overall, the results indicate that the application of further emission controls to local point sources of particles would have less influence on fine aerosol and sulfate concentrations than would the control of more distant emissions causing aerosols transported into the Boston vicinity.

A real-time particle-mass sampling system for applications in the stack of an industrial power plant

A real-time particle-mass monitor has been developed for operation in stack gas environments. It provides mass measurements of sampled particles in real time (response time less than a few seconds) without diluting or cooling the sampled gas. Measurement biases of the type encountered in conventional physical sampling techniques are minimized. The performance of a system prototype has been tested in the laboratory and in the flue gas of a cool-fired power plant. Preliminary test results and operational experience for the prototype are reported.

An Updated Gaussian Plume Model for Tall Stacks

This paper describes and evaluates a Gaussian plume model, PPSP, which Incorporates stability and dispersion parameters and plume rise formulas based on contemporary understanding of the planetary boundary layer. The model improvements over older Gaussian models such as CRSTER focus on daytime convective conditions, which Is when tall stacks usually yield their highest ground level concentrations. A major model advancement is the use of u/w* as the stability parameter during daytime rather than the Turner criteria. Here, u is the mean wind speed in the boundary layer, and w* is the convective velocity scale, which depends on the cube root of the surface heat flux and boundary layer depth. Other model Improvements include: 1) incorporation of Briggs’ dispersion parameters for elevated sources Instead of the Pasquill-Gifford curves for ground sources, 2) use of Briggs’ 1975 plume rise formulas, which address convectively generated turbulence, rather than his pre-1975 formulas, which do not, and 3) adoption of Briggs’ 1980 criteria for plume penetration of elevated stable layers instead of the simple "all or none" approach of the CRSTER model. Evaluation of the PPSP model with an extensive set of ground level SO2 measurements downwind of power plant stacks shows that it performs much better than the CRSTER model.

The Determination of Density Variation in Radiation Protective Walls of Concrete by Means of Bremsstrahlung of 10 MeV from Linear Accelerator

Testing the function of meter-thick radiation protective walls as built e.g. for the reactor stacks of nuclear power plants shows that the relative density variations of concrete multiplied by the number of the mean free paths of the radiation in concrete have an effect on the dose rate variations behind the protective wall. It is therefore necessary to carefully control the density of concrete. If ultrasonic testing of the walls has to be excluded because they are hermetically enclosed with a steel liner on either side and gamma-radiography fails due to the mass per unit area in the order of several tons/m2, then another method, the transmission with bremsstrahlung of adequate energy, e.g. of 10 MeV, can be applied. Such bremsstrahlung can be received from a mobile and portable linear accelerator. In the paper the first results of the determination of density variations in a model wall of concrete having masses per volume area in the range from 1800 kg ⋅ m−3 to 2400 kg ⋅ m−3 and linear dimensions 1,60 m ...

Real-Time Total Mass Analysis of Particulate in the Stack of an Industrial Power Plant

A real-time particulate mass monitor has been developed for operation in stack gas environments. It provides mass measurements of sampled particles in real time (response time less than a few seconds) without diluting or cooling the sampled gas. Measurement biases of the type encountered in conventional physical sampling techniques are minimized. The performance of a system prototype has been tested in the laboratory and in the flue gas of a coal-fired power plant. Preliminary test results and operational experience for the prototype are reported.

THEORY OF SLOW SECOND ORDER REACTIONS IN POWER PLANT PLUMES: COMPARISON WITH PRELIMINARY DATA

Slow second order reactions in which plume travel time is short compared to characteristic chemical reaction times are incorporated into the conservation equations for a buoyant plume in a crosswind. In the theory, a source term has been written for a second order irreversible reaction of the form A + B → AB. Approximate solutions to the conservation equations are derived in the near and far-field and compared with numerical results for a representative range of stack exit parameters. The relative contribution of near and far-field kinetics to the end-point conversion ratio [AB]/[A] is predicted with the approximate expressions. Expected errors between asymptotic predictions of the conversion ratio [AB]/[A] and numerical results are demonstrated for a wide range of stack exit parameters. The direct application of these useful results to the prediction of expected levels of sulfate formation from power plant stacks are demonstrated and a comparison is made with limited wind tunnel data.

Primary Sulfates in Atmospheric Sulfates: Estimation by Oxygen Isotope Ratio Measurements

The relative amounts of primary and secondary sulfates in atmospheric aerosols and precipitation can be estimated from measurements of the stable oxygen isotope ratios. The oxygen-18 content of sulfates formed in power plant stack gases before emission into the atmosphere is significantly higher than that of sulfates formed from sulfur dioxide after emission. Results show that 20 to 30 percent of the sulfates in rain and snow at Argonne, Illinois, are of primary origin.