Incinerator Conference Covers Emissions Control Aspects

The success of the application of computer modeling to decision-making will depend on the degree to which the scientifically valid “cause-and-effect” features of the air pollution system are represented. For this reason, dynamic simulation models are to be preferred to statistical and empirical models. A digital simulation model based on a stoichiometrically logical chemical mechanism and trajectory estimating routines was constructed, using Los Angeles source, meteorological and geographic input. The basic physical concept underlying the simulation model is the process of evolution of photochemical pollution in a parcel of air as it moves in a dynamic urban emission/meteorological environment along a given urban wind trajectory. Both the photochemical evolution and the trajectory are numerically integrated by a standard linear multistep predictor-corrector method. Concentrations of photochemical reactants and products (i.e., primary and secondary contaminants) are determined by this numerical integration, which also includes appropriate terms for relevant effects. In five preliminary validation runs, simulated NO₂, NO, and O₃ values were within 20% or 0.05 ppm of those observed at air monitoring stations located near the termini of the runs. The trajectories were plotted on the basis of hourly meteorological data for 22 stations. Six control strategy exercises were conducted to illustrate the application of the model to problem-solving situations.     

Control of Mercury Emissions from a Municipal Solid Waste Incinerator in Japan

Abstract

The control of Hg emissions from a municipal solid waste incinerator (MSWI) is very important, because more than 78% of municipal solid waste (MSW) is incinerated. The Hg content of coal used in utility boilers is relatively low in Japan. In this study, recent trends in the Hg content of MSW in Japan and activated carbon (AC) injection as a control technology of Hg emission from an MSWI are discussed. The effect of AC injection on Hg removal from flue gas in an MSWI was investigated by pilot-scale experiments using a bag filter (BF). The injection of AC increases the Hg reduction ratio by 20–30% compared with cases without AC injection. The Hg reduction ratio increases as the flue gas temperature decreases. The Hg reduction ratio is closely related to the inlet Hg concentration and was expressed with a Langmuir-type adsorption isotherm.     

Simultaneous Control of PCDD/PCDF,HCI and NOX Emissions from Municipal Solid Waste Incinerators with Ammonia Injection

This article Introduces a technology for the simultaneous control of the emissions of PCDD/ PCDF, hydrochloric acid (HCI) and nitrogen oxides (NO_x) from municipal solid waste (MSW) Incinerators. The technology uses ammonia as the control medium for all three pollutants. In this paper, the theoretical basis of the technology Is discussed. In addition, a bench-scale experiment proving the theory Is described and the practical application of the theory Is presented. Finally, further steps which are being taken to develop the technology for commercial application are detailed.     

Alternative Strategies for Control of Sulfur Dioxide Emissions

Achievement of air quality goals now more than ever requires careful consideration of alternative control strategies in view of national concerns with energy and the economy. Three strategies which might be used by coal-fired steam electric plants to achieve ambient air quality standards for sulfur dioxide have been compared, and the analysis shows that the desired objective can be achieved using the intermittent control strategy with substantially less impact on the environment, less consumption of energy, and at a much lower economic cost than using either stack gas scrubbing or low-sulfur coal.     

Incineration Techniques for Control of Volatile Organic Compound Emissions

A review of incineration techniques for control of volatile organic compound emissions is presented in two consecutive issues o/JAPCA. Part I presented an overview of the process including fundamentals and design considerations. Both thermal and catalytic incinerators were considered. Part IIpresents capital and annual operating cost estimates for both thermal and catalytic incinerator systems based on information received from a number of equipment manufacturers.     

中外饮食业油烟控制标准比较

饮食油烟的污染日益受到人们的重视，许多国家已制订了油烟排放的标准。作者从不同角度比较了4个国家或地区的饮食业油烟控制标准的异同，为我国今后饮食业油烟污染控制的技术开发、标准修订、产品推广等提供参考。     

A Numerical Modeling Technique for Estimating Sulfur Dioxide Dry Deposition Due to Local Source Emissions

This paper describes a methodology for estimating the effect of local source emissions on dry deposition of sulfur dioxide in regions of complex terrain. Airflow in complex terrain is simulated by a time-dependent dynamical model for the meteorological fields. The results of the dynamical model are used to drive a semi-stochastic Lagrangian dispersion model in order to evaluate concentrations resulting from local source emissions. The Lagrangian dispersion model is coupled with a dry deposition treatment which includes the effects of both surface properties and micrometeoroiogical factors on deposition.

A sample application is discussed for a source in the Shenandoah Valley. The largest concentrations and deposition rates were obtained shortly after sunrise, during the transition from the nocturnal to the daytime flow regime. These results suggest that dry deposition may be episodic.     

CaCO3类吸收剂净化焚烧烟气中HCI气体的研究

通常烟气中的酸性气体采用Ca（OH）2净化，然而当烟气温度在300℃以上时，Ca（OH）2喷入到烟气中将快速生成CaCO3。研究了两种CaCO3的反应特性，比较了200-900℃内CaCO3类吸收剂和Ca（OH）2与烟气中HCl气体的反应率，发现在600℃左右和800℃及以上，CaCO3类吸收剂的反应率与Ca（OH）2相当或更高；CaCO3类吸收剂、特别是改性CaCO3可替代Ca（OH）2作为干式净化HCl气体的吸收剂，合适的反应温度在600℃左右。     

A Model for Gaseous Pollutant Sorption by Leaves

A model simulating pollutant exchange with isolated leaves that integrates factors which have been found to be important in regulating pollutant uptake by leaves is presented. The model is patterned after an electrical analogue simulator and was designed to emphasize the effects of pollutant and leaf properties on the process. The article discusses the relative significance of factors affecting gas transfer, sorption of pollutants by leaf surfaces, and pollutant solubility and fate on the uptake process. Data is presented showing uptake of ozone by exposed mesophyll and several epidermal surfaces chosen for their different surface characteristics. The model was used to derive a mathematical expression for the exchange process which was rearranged to define internal (average) pollutant solute concentration in terms of external concentration, leaf and boundary layer diffusion resistance, surface sorption and pollutant solubility. The importance of estimating internal solute concentration is discussed.     

Control of Particulate Emissions from Turbine Engine Test Cells by Cooling Water Injection

Abstract

This paper presents an experimental study of calcium bisulfite oxidation, a key step in the wet limestone-gypsum flue gas desulfurization (FGD) process, in the presence of catalysts (e.g., cobalt ions and a mixture of ferrous and cobalt ions). A fundamental approach is followed, by reproducing a simplified synthetic FGD liquor in which both catalyst ions, alone or mixed together, are present. A laboratory-scale apparatus is used, in which sulfurous solution is contacted with a gas phase at a fixed oxygen partial pressure (21.3 kPa) and at different temperature levels (25, 45, and 55 °C). The experimental results are analyzed using the theory of gas-liquid mass transfer with chemical reaction, showing that the slow reaction regime is explored and the transition from the kinetic to the diffusional subregime is identified. The experimental results are compared with those obtained in the presence of other catalytic species (manganese and ferrous ions), showing that cobalt is effective in catalyzing the oxidation of calcium bisulfite to sulfate, but to a minor extent with respect to iron and manganese.     

Control of Coke Oven Emissions by Use of A Closed Pipeline Charging System

The body of information presented in this paper is directed to those individuals concerned with the control of air pollution emissions which occur as a result of the operation of by-product coke plants. It describes a new process which represents a major change in the charging operation wherein preheated coal can be charged to coke ovens via a closed pipeline system thus replacing the conventional larry charging car and thereby eliminating air pollution estimated to be as much as 70% of the total emissions from coke oven operations. Coal is dried and preheated in a continuous fluidized bed process utilizing products of combustion of coke oven gas. The coal is recovered in conventional cyclone collectors and conveyed to the ovens via a new and novel pneumatic conveying system where the gas used is superheated steam. Jet energy repeatedly thrusts the coal upward and forward through the pipe, obtaining a high efficiency of transport of solids ten times that of conventional systems. Major advantages of the process demonstrated to date include (1) elimination of emissions from charging, (2) reduction of emission from pushing, (3) improved battery top working conditions, (4) increased oven productivity as much as 45%.     

Measuring the Organic Carbon Content of Source Emissions for Air Pollution Control

Measuring emissions of organic materials from such sources as paint bake ovens, degreas-ing operations, and printing processes is a necessy part of a control program for solvents. Over the intervening years since 1966 when Los Angeles first enacted its solvent Rule 66, a considerable number of tests have been performed and the present test method has gone through a period of experience and improvement. A sample is collected from a stack or vent in a freeze-out trap cooled with dry ice followed by an evacuated 8-liter tank. Analysis is done by a system of gas chromatography and catalytic combustion to yield the total organic carbon content. Representative industrial emission analysis results, which demonstrate the practical applicability of the system, are shown.     

An Evaluation of Emissions and Control Technologies for the Metal Decorating Process

Data are reported on a number of controlled and uncontrolled sources from various metal decorating operations. Emission levels are related to process variables such as ink coverage, coater speed, sheet size, and applied coating film weight. Results are presented depicting variation of organic emission levels from a coating process line with elapsed process time. For controlled sources employing either catalytic or thermal incineration, conversion efficiencies are reported as a function of temperature. Operational curves are presented for each control system studied indicating the dependence of carbon dioxide, NO_x, and organic output on incineration temperatures.     

An Evaluation of Emissions and Control Technologies for the Metal Decorating Process

A simple but effective sampling and analytical procedure is described for determining total organics, carbon dioxide, carbon monoxide, and methane emitted from web offset printing presses. Data are reported on a number of controlled and uncontrolled sources and emission levels are related to process variables such as press speed, ink coverage and dryer type. For controlled sources employing either catalytic or thermal incineration units, conversion efficiencies are reported as a function of temperature. Operational curves are presented for each control system studied indicating the dependency of carbon dioxide, NO_xt and organic output to incineration temperatures.     

Low Concentration Mercury Sorption Mechanisms and Control by Calcium-Based Sorbents: Application in Coal-Fired Processes

ABSTRACT

The capture of elemental mercury (Hg⁰) and mercuric chloride (HgCl₂) by three types of calcium (Ca)-based sor-bents was examined in this bench-scale study under conditions prevalent in coal-fired utilities. Ca-based sorbent performances were compared with that of an activated carbon. Hg⁰ capture of about 40% (nearly half that of the activated carbon) was achieved by two of the Ca-based sorbents. The presence of sulfur dioxide (SO₂) in the simulated coal combustion flue gas enhanced the Hg⁰ capture from about 10 to 40%. Increasing the temperature in the range of 65-100 °C also caused an increase in the Hg⁰ capture by the two Ca-based sorbents. Mercuric chloride (HgCl₂) capture exhibited a totally different pattern. The presence of SO₂ inhibited the HgCl₂ capture by Ca-based sorbents from about 25 to less than 10%. Increasing the temperature in the studied range also caused a decrease in HgCl₂ capture. Upon further pilot-scale confirmations, the results obtained in this bench-scale study can be used to design and manufacture more cost-effective mercury sorbents to replace conventional sorbents already in use in mercury control.     

Transferable Discharge Permits for Control of SO2 Emissions from Illinois Power Plants

A large scale simulation model was employed in evaluating various policy alternatives for reducing SO₂ emissions from Illinois electric power plants for a broad range of nuclear power capacity addition scenarios. A dynamic simulation of a transferable discharge permit (TDP) program suggests a market oriented management system can assure an acceptable level of environmental quality while achieving typical cost savings of 40-60 percent over a program based on uniform decreases in existing emission standards. This cost advantage can be realized without any major decline in the demand for coal generally or indigenous coals in particular. Several options for initiating the TDP market are evaluated. The analysis concludes that initiating the market by government sales may not constitute a major financial burden on the electric utilities or their customers.     

The Development of a Condenser for Odor Control from Dry Rendering Plants

A new surface condenser and carbon adsorber has been developed which provides arc economic solution to the problem of odours from dry rendering plants.     

Scientific Basis of an Improved EPA Policy on Control of Organic Emissions for Ambient Ozone Reduction

ABSTRACT

This article describes an effort to re-examine the scientific bases of the existing, more than two decades-old U.S. Environmental Protection Agency (EPA) policy on volatile organic compound reactivity in light of recent scientific knowledge and understanding. The existing policy allows “negligibly reactive” organic emissions, that is, emissions with ambient ozone production potential lower than that of ethane, to be exempted from all ozone regulations. It relies on use of k_OH and incremental reactivity data for determining whether an organic compound is negligibly reactive. Recent scientific evidence suggests that (1) exempting the negligibly reactive organic emissions from all regulations is unjustifiable, (2) the choice of ethane as the benchmark organic species for distinguishing reactive from negligibly reactive organics may be inappropriate, (3) the assumptions and methods used for classifying organic compounds as “reactive” and “negligibly reactive” should be reconsidered, and (4) the volatility factor should be considered, more appropriately, in much the same way as the reactivity factor.