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%.     

An Inexpensive Remote Sequential Air Sampler

A remote sequential air sampling unit has been developed which is compact, lightweight, and quite inexpensive. The sampling device contains a number of spring-loaded syringes which are released sequentially by the motion of a rotary mechanical timer. Field tests indicate that the sampling device can take accurate sequential air samples automatically and contain each sample without leakage for at least a period of 18 hours in an outdoor environment.     

An Equilibrium Analysis of Some Chlorinated Hydrocarbons in Stoichiometric to Fuel-rich Post-flame Combustion Environments

The equilibrium composition of product gases from the combustion of chlorinated hydrocarbons (CHC) has been studied for varying ratios of C, H, Cl, and O under stoichiometric to fuel-rich conditions. An interactive, PC-compatible FORTRAN program, STANJAN, was utilized in conjunction with thermochemical data sources to calculate equilibrium compositions of gas mixtures as a function of temperature. The predicted results, when judiciously Interpreted, assist in the understanding of the potential for formation of residual organic substance emissions (ROSEs) in post-flame environments of an incinerator.

Arguments are presented for the potential formation of chlorinated species, which are stable at ambient temperature, if locally fuel-rich mixtures penetrate into the lower temperature zones of an incinerator. ROSEs that have been observed in field tests of incinerators burning chlorinated compounds are predicted to form under the fuel-rich condition. Furthermore, when the equivalence ratio is greater than unity by even a slight amount, the degree of chlorination of product gases increases markedly when the Cl/H ratio also exceeds unity. In that case, time, temperature, turbulence and an overall fuel-lean stoichiometry may not be sufficient to guarantee elimination of measurable levels of chlorinated products. Possible implications of the equilibrium calculations are discussed. Further systematic studies with additional CHCs, nitrogen?, sulfur?, and heavy metal-bearing compounds are recommended as well as continued efforts to carry out kinetic studies.     

The Odor Impact Model

Abstract

This paper presents the simulation and field evaluation results of two approaches to localize pollutant emission sources with open-path Fourier transform infrared (OPFTIR) spectroscopy. The first approach combined the plume’s peak location information reconstructed from the Smooth Basis Function Minimization (SBFM) algorithm and the wind direction data to calculate source projection lines. In the second approach, the plume’s peak location was determined with the Monte Carlo methodology by randomly sampling within the beam segment having the largest path-integrated concentration. We first conducted a series of simulation studies to investigate the sensitivity of using different basis functions in the SBFM algorithm. It was found that fitting with the beta and Weibull basis functions generally gave better estimates of the peak locations than with the normal basis function when the plumes were mainly within the OP-FTIR’s monitoring line. However, for plumes that were symmetric to the peak position or spread over the OP-FTIR, fitting with the normal basis function gave better performance. In the field experiment, two tracer gases were released simultaneously from two locations and the OP-FTIR collected data downwind from the sources with a maximum beam path length of 97 m. For the first approach, the release locations were within the 0.25- to 0.5-probability area only after the uncertainty of the peak locations was included in the calculation process. The second approach was easy to implement and still performed as satisfactorily as the first approach. The distances from the sources to the best-fit lines (i.e., the regression lines) of the estimated locations were smaller than 10 m.     

Design Scenario for the Radioisotopic Estimation of the Biogenic Component of Airborne Particles

Abstract

An experimental design is described to estimate the fraction of secondary fine particle from the biogenic component of volatile organic compounds (VOCs) in the atmosphere using radiocarbon isotopic abundance ratios. The method distinguishes between “modern” carbon (C), and “old” C of primary and secondary origins based on three components, condensed-phase organic carbon (OC), semi-volatile particulate compounds (SVOCs), and VOCs. The method depends on interpretation of diurnal and seasonal variation in OC, SVOC, and VOC concentrations. Sampling employs a filter-denuder unit, which collects the three C components for isotopic analysis. The samples are collected repetitively for a daily sequence of the same hourly intervals covering diurnal periods with similar meteorological conditions. Collected C is thermally treated to separate OC from black carbon on filters and VOCs or SVOCs from adsorbents, with all four fractions individually oxidized to carbon dioxide to determine the radiocarbon content by accelerator mass spectrometry. Using C isotope abundance, the data are interpreted for fractions of primary modern C and secondary modern C as estimated from averaging diurnal and seasonal variations in the concentration data. As support for interpretation, samples of OC, SVOCs, and VOCs would be analyzed for speciation to identify source indicator species present.     

Stratospheric ozone,global warming,and the principle of unintended consequences—An ongoing science and policy story

Supplemental Materials: Supplemental materials are available for this paper. Go to the publisher's online edition of the Journal of the Air & Waste Management Association.      

Airborne Emissions of Mercury from Municipal Solid Waste. I: New Measurements from Six Operating Landfills in Florida

Abstract

Mercury-bearing material enters municipal landfills from a wide array of sources, including fluorescent lights, batteries, electrical switches, thermometers, and general waste; however, the fate of mercury (Hg) in landfills has not been widely studied. Using automated flux chambers and downwind atmospheric sampling, we quantified the primary pathways of Hg vapor releases to the atmosphere at six municipal landfill operations in Florida. These pathways included landfill gas (LFG) releases from active vent systems, passive emissions from landfill surface covers, and emissions from daily activities at each working face (WF). We spiked the WF at two sites with known Hg sources; these were readily detected downwind, and were used to test our emission modeling approaches. Gaseous elemental mercury (Hg⁰) was released to the atmosphere at readily detectable rates from all sources measured; rates ranged from ～1–10 ng m^?2 hr^?1 over aged landfill cover, from ～8–20 mg/hr from LFG flares (LFG included Hg⁰ at μg/m³ concentrations), and from ～200–400 mg/hr at the WF. These fluxes exceed our earlier published estimates. Attempts to identify specific Hg sources in excavated and sorted waste indicated few readily identifiable sources; because of effective mixing and diffusion of Hg⁰, the entire waste mass acts as a source. We estimate that atmospheric Hg releases from municipal landfill operations in the state of Florida are on the order of 10–50 kg/yr, substantially larger than our original estimates, but still a small fraction of current overall anthropogenic losses.