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.     

Measuring Concentrations of Volatile Organic Compounds in Vinyl Flooring

ABSTRACT

The initial solid-phase concentration of volatile organic compounds (VOCs) is a key parameter influencing the emission characteristics of many indoor materials. Solid-phase measurements are typically made using solvent extraction or thermal headspace analysis. The high temperatures and chemical solvents associated with these methods can modify the physical structure of polymeric materials and, consequently, affect mass transfer characteristics.

To measure solid-phase concentrations under conditions resembling those in which the material would be installed in an indoor environment, a new technique was developed for measuring VOC concentrations in vinyl flooring (VF) and similar materials. A 0.09-m² section of new VF was punched randomly to produce ~200 0.78-cm² disks. The disks were milled to a powder at -140 °C to simultaneously homogenize the material and reduce the diffusion path length without loss of VOCs. VOCs were extracted from the VF particles at room temperature by fluidized-bed desorption (FBD) and by direct thermal desorption (DTD) at elevated temperatures. The VOCs in the extraction gas from FBD and DTD were collected on sorbent tubes and analyzed by gas chromatog-raphy/mass spectrometry (GC/MS). Seven VOCs emitted by VF were quantified. Concentration measurements by FBD ranged from 5.1 |ig/g VF for n-hexadecane to 130 |Jg/g VF for phenol. Concentrations measured by DTD were higher than concentrations measured by FBD. Differences between FBD and DTD results may be explained using free-volume and dual-mobility sorption theory, but further research is necessary to more completely characterize the complex nature of a diffusant in a polymer matrix.     

The Missoula Valley Semivolatile and Volatile Organic Compound Study: Seasonal Average Concentrations

Abstract

The city of Missoula is located in a high mountain valley (elevation 3200 ft) in western Montana and contains one of the largest populations in the entire Rocky Mountain Region completely enclosed by mountains. During the 2000/2001 Missoula Valley Sampling Program, ambient levels of 61 semivolatile organic compounds (SVOCs) and 54 volatile organic compounds (VOCs) were originally quantified before refining the analytical program to 28 of the most prominent SVOCs and VOCs found in the Missoula Valley airshed. These compounds were measured over 24-hr periods at two locations throughout an entire year. This study provides the first, comprehensive appraisal of the levels of SVOCs and VOCs measured simultaneously throughout all four seasons at two locations in the Missoula Valley, including those levels measured during the 2000 Montana wildfire season. Generally, SVOC levels were comparable between both sides of the Missoula Valley. However, there were nearly double the amount of VOCs measured at the more urban Boyd Park site compared with the rural Frenchtown sampling site, a result of the greater number of automobiles on the eastern side of the Valley. SVOCs and VOCs were measured at their highest levels of the sampling program during the winter. Forest fire smoke samples collected during the summer of 2000 showed significant increases in SVOC phenolic compounds, including phenol, 2-methylphenol, 4-methylphenol, and 2,4-dimethylphenol. Although there were modest increases in some of the other SVOCs and VOCs measured during the fire season, none of the increases were as dramatic as the phenolics.     

Economic Study of the Tunable Electron Beam Plasma Reactor for Volatile Organic Compound Treatment

ABSTRACT

A tunable electron beam generated plasma system has been developed for selective cold plasma treatment of dilute concentrations (1-3,000 ppm range) of hazardous compounds in gaseous waste treatment. This system, referred to as the Tunable Hybrid Plasma (THP), has shown a high degree of efficiency and effectiveness in both laboratory and field tests. Decomposition energy requirements are in the 100 eV per molecule range for treatment of carbon tetrachloride and 10 eV for treatment of trichloroethylene.

A cost comparison has been made between the Tunable Hybrid Plasma (THP) technology and three conventional technologies used for emission control of volatile organic compounds (VOCs): granular activated carbon, thermal incineration, and catalytic oxidation. In addition to its environmentally attractive features, THP technology has the potential to be lower cost than other technologies over a range of concentrations and flow rates. Cost projections for the THP system for decomposition of trichloroet-hylene are around 50 cents/lb for initial concentrations in the few hundred ppm range and flow rates of 5,000 cfm or greater and around $1/lb for 1,000 cfm flow rates. Cost projections for carbon tetrachloride and trichloroethane decomposition using the THP technology are several dollars per pound. The costs for THP treatment are generally significantly lower than costs for use of granular activated carbon and are also quite competitive with costs for thermal incineration and catalytic oxidation.     

Total Volatile Organic Compounds in the Urban Environment of Delhi

ABSTRACT

Total volatile organic compounds (TVOCs) in the urban ambient environment of Delhi were monitored from November 1994 to June 1995 at 13 sites using an inexpensive and a manual-labor-intensive sample collection procedure in want of sophisticated equipment. The results of the study show appreciable levels of TVOCs in the ambient environment of Delhi. The amount of TVOCs in the ambient environment was found to vary between 3 and 42 ppmv and exhibited wide temporal and seasonal variations. On a diurnal cycle, TVOC levels mostly peaked at 9:00 a.m., which coincided with the peak traffic hour. TVOC buildup in the urban atmosphere has serious implications for air quality through the formation of highly toxic oxidants. The results of this preliminary study make out a strong case for a regular monitoring of TVOCs in the urban environment of Delhi.     

Wet Scrubber Analysis of Volatile Organic Compound Removal in the Rendering Industry

Abstract

The promulgation of odor control rules, increasing public concerns, and U.S. Environmental Protection Agency (EPA) air regulations in nonattainment zones necessitates the remediation of a wide range of volatile organic compounds (VOCs) generated by the rendering industry. Currently, wet scrubbers with oxidizing chemicals are used to treat VOCs; however, little information is available on scrubber efficiency for many of the VOCs generated within the rendering process. Portable gas chromatography/mass spectrometry (GC/MS) units were used to rapidly identify key VOCs on-site in process streams at two poultry byproduct rendering plants. On-site analysis was found to be important, given the significant reduction in peak areas if samples were held for 24 hr before analysis. Major compounds consistently identified in the emissions from the plant included dimethyl disulfide, methanethiol, octane, hexanal, 2-methylbutanal, and 3-methylbutanal. The two branched aldehydes, 2-methylbutanal and 3-methylbutanal, were by far the most consistent, appearing in every sample and typically the largest fraction of the VOC mixture.

A chlorinated hydrocarbon, methanesulfonyl chloride, was identified in the outlet of a high-intensity wet scrubber, and several VOCs and chlorinated compounds were identified in the scrubbing solution, but not on a consistent basis. Total VOC concentrations in noncondensable gas streams ranged from 4 to 91 ppmv. At the two plants, the odor-causing compound methanethiol ranged from 25 to 33% and 9.6% of the total VOCs (v/v). In one plant, wet scrubber analysis using chlorine dioxide (ClO2) as the oxidizing agent indicated that close to 100% of the methanethiol was removed from the gas phase, but removal efficiencies ranged from 20 to 80% for the aldehydes and hydrocarbons and from 23 to 64% for total VOCs. In the second plant, conversion efficiencies were much lower in a packed-bed wet scrubber, with a measurable removal of only dimethyl sulfide (20–100%).     

Determination of Source Contributions to Ambient Volatile Organic Compound Concentrations in Berlin

ABSTRACT

During three measuring campaigns in June, July, and August 1996, volatile organic compound (VOC) concentrations were measured at a rural background site, a city residential site, and a street site in Berlin. In addition, samples were taken near relevant sources of VOCs. The meaurements covered the volatile hydrocarbons in the range C₁-C₁₄ and included aldehydes and ketones. Samples were taken at four characteristic periods of 2 hr/day: during the night, during the early morning rush hour, at midday, and during the evening rush hour. An assessment of the contribution of emission categories to the observed concentrations was made with the chemical mass balance (CMB) modelling technique.

The VOC concentrations at the residential area and at the street site in the inner city were, respectively, a factor of 3 and 7 above the background concentration. Traffic exhaust contributed approximately 80-90% of the non-methane hydrocarbon (NMHC) concentration in the inner city and approximately 60% at the background area. Evaporative losses of motor fuel are estimated to account for approximately 7% at all sites. Natural gas leakage also contributed significantly to the observed VOC concentrations: in the inner city approximately 510% and at the background area approximately 30%. The measurements also showed a contribution of smaller sources, such as dry cleaning, use of solvents, and bio-genic emissions. However, the contribution of these sources to the total observed concentrations at the sites is estimated to be very small.     

A New Method for the Rapid Determination of Volatile Organic Compound Breakthrough Times for a Sorbent at Concentrations Relevant to Indoor Air Quality

Abstract

The use of sorbents has been proposed to remove volatile organic compounds (VOCs) present in ambient air at concentrations in the parts-per-billion (ppb) range, which is typical of indoor air quality applications. Sorbent materials, such as granular activated carbon and molecular sieves, are used to remove VOCs from gas streams in industrial applications, where VOC concentrations are typically in the parts-per-million range. A method for evaluating the VOC removal performance of sorbent materials using toluene concentrations in the ppb range is described. Breakthrough times for toluene at concentrations from 2 to 7500 ppb are presented for a hydrophobic molecular sieve at 25% relative humidity. By increasing the ratio of challenge gas flow rate to the mass of the sorbent bed and decreasing both the mass of sorbent in the bed and the sorbent particle size, this method reduces the required experimental times by a factor of up to several hundred compared with the proposed American Society of Heating, Refrigerating, and Air-Conditioning Engineers method, ASHRAE 145P, making sorbent performance evaluation for ppb-range VOC removal more convenient. The method can be applied to screen sorbent materials for application in the removal of VOCs from indoor air.     

Performance of a Pilot-Scale Biotrickling Filter in Controlling the Volatile Organic Compound Emissions in a Furniture Manufacturing Facility

Abstract

A 0.75-m³ pilot-scale biotrickling filter was run for over 1 yr in a Spanish furniture company to evaluate its performance in the removal of volatile organic compounds (VOCs) contained in the emission of two different paint spray booths. The first one was an open front booth used to manually paint furniture, and the second focus was an automatically operated closed booth operated to paint pieces of furniture. In both cases, the VOC emissions were very irregular, with rapid and extreme fluctuations. The pilot plant was operated at an empty bed residence time (EBRT) ranging from 10 to 40 sec, and good removal efficiencies of VOCs were usually obtained. When a buffering activated carbon prefllter was installed, the system performance was improved considerably, so a much better compliance with legal constraints was reached. After different shutdowns in the factory, the period to recover the previous performance of the biotrickling reactor was minimal. A weekend dehydration strategy was developed and implemented to control the pressure drop associated with excessive biomass accumulation.     

Source Location and Characterization of Volatile Organic Compound Emissions at a Petrochemical Plant in Kaohsiung,Taiwan

Abstract

This paper elucidated a novel approach to locating volatile organic compound (VOC) emission sources and characterizing their VOCs by database and contour plotting. The target of this survey was a petrochemical plant in Linyan, Kaohsiung County, Taiwan. Samples were taken with canisters from 25 sites inside this plant, twice per season, and analyzed by gas chromatography–mass spectrometry. The survey covered 1 whole year. By consolidated into a database, the data could be readily retrieved, statistically analyzed, and clearly presented in both table and graph forms. It followed from the cross‐analysis of the database that the abundant types of VOCs were alkanes, alkenes/dienes, and aromatics, all of which accounted for 99% of total VOCs. By contour plotting, the emission sources for alkanes, aromatics, and alkenes/dienes were successfully located. Through statistical analysis, the database could provide the range and 90% confidence interval of each species from each emission source. Both alkanes and alkene/dienes came from tank farm and naphtha cracking units and were mainly composed of C₃–C₅ members. Regarding aromatics, benzene, toluene, and xylenes were the primary species; they were emitted from tank farm, aromatic units, and xylene units.     

Inter-Urban Comparison of Ambient Volatile Organic Compound Concentrations in U.S. Cities

Airborne particulate matter from three ferrous foundries was sampled in granulometric fractions and analyzed by scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDXA), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) to determine morphology and qualitative bulk and surface chemical compositions. Cluster and principal components analyses (PCA) were used as an aid for interpretation of results. A clear pattern of composition as a function of size emerges; in particular, trace metals accumulate in fine particles and volatile species on the surface of these. Chemical composition changes are also related to daily schedules where applicable: trace metals appear during pouring operations, silicon is generated during mold making and unmolding. Cluster and PCA greatly ease examination of data and offer pictorial representations of results; in particular, the chemical composition versus particle size relationship is very neatly illustrated by PCA graphs.     

Biofiltration of a Mixture of Volatile Organic Emissions

ABSTRACT

Air biofiltration is now under active consideration for the removal of the volatile organic compounds (VOCs) from polluted airstreams. To optimize this emerging environmental technology and to understand compound removal mechanisms, a biofilter packed with peat was developed to treat a complex mixture of VOCs: oxygenated, aromatic, and chlorinated compounds. The removal efficiency of this process was high. The maximum elimination capacity (ECmax) obtained was ~120 g VOCs/m³ peat/hr. Referring to each of the mixture's components, the ECmax showed the limits in terms of biodegradability of VOCs, especially for the halogenated compounds and xylene.

A stratification of biodegradation was observed in the reactor. The oxygenated compounds were metabolized before the aromatic and halogenated ones. Two assumptions are suggested. There was a competition between bacterial communities. Different communities colonized the peat-based biofilter, one specialized for the elimination of oxygenated compounds, the others more specialized for elimination of aromatic and halogenated compounds. There was also substrate competition. Bacterial communities were the same over the height of the column, but the more easily biodegradable compounds were used first for the microorganism metabolism when they were present in the gaseous effluent.     

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.     

Evaluation of Canisters for Measuring Emissions of Volatile Organic Air Pollutants from Hazardous Waste Incineration

Regulation to control air emissions of toxic organic compounds require the collection and analysis of effluent gas from low level sources such as hazardous waste incinerators. The standard SW- 846 Method specifies the use of Tenax and Tenax/charcoal adsorbent traps for collection of volatile organics from incinerators. This study evaluates passivated stainless steel canisters as an alternative to adsorbent traps to eliminate some of the problems associated with adsorbent sampling. Initially the stability of 18 nonpolar, volatile organic compounds was determined in Summa-treated stainless steel canisters with greater than 100 ppmv HCI and saturated with water vapor. All 18 components were stable for a twoweek period; however, an Interference caused a 10-fold increase In the FID response of trlchloroethylene, toluene, and chlorobenzene. No Interference of the ECD response was found for any of the 11 compounds detected with the ECD including trlchloroethylene. A pilot scale incinerator was sampled using canisters, and the destruction efficiency of 1,1,1-trichloroethane was determined at a concentration of less than 0.5 ppbv while determining 1,1-dichloroethylene, the major product of Incomplete combustion, at a concentration of 8000 ppbv from the same sample.     

Evaluation of a Test Method for Measuring Indoor Air Emissions from Dry-Process Photocopiers

ABSTRACT

A large chamber test method for measuring indoor air emissions from office equipment was developed, evaluated, and revised based on the initial testing of four dry-process photocopiers. Because all chambers may not necessarily produce similar results (e.g., due to differences in sink effects, temperature and humidity control, air exchange, pollutant monitoring, and measurement biases), a preliminary four-laboratory evaluation of the revised test method was conducted. To minimize variability, the evaluation used a single dry-process photocopier that was shipped to each of the four laboratories along with supplies (i.e., toner and paper).

The results of this preliminary four-laboratory evaluation demonstrate that the test method was used successfully in the different chambers to measure emissions from dry-process photocopiers. Differences in chamber design and construction appeared to have had minimal effect on the results for the volatile organic compounds (VOCs). Perhaps more important than the chamber itself is the sample analysis as identified by duplicate samples that were analyzed by a different laboratory. Percent relative standard deviation (%RSD) was used to provide a simplistic view of interlaboratory precision for this evaluation. Excluding problems with suspected analytical bias observed from one of the laboratories, the precision was excellent for the VOCs with RSDs of less than 10% in most cases. Less precision was observed among the laboratories for aldehydes/ketones (RSD of 23.2% for formaldehyde). The precision for ozone emission rates among three of the laboratories was excellent (RSD of 7.9%), but emission rates measured at the fourth laboratory were much higher.     

Sources of Volatile Organic Compounds in a University Building

A total of 34 volatile organic compounds (VOCs) were measured in the indoor of laboratories, offices and classrooms of the Chemical Engineering Department of Hacettepe University in Ankara in 2 week-day passive sampling campaigns. The average concentrations ranged from 0.77 to 265 μg m^?3 at the different indoor sites, with the most abundant VOC found to be toluene (119.6 μg m^?3), followed by styrene (21.24 μg m^?3), 2-ethyltoluene (17.11 μg m^?3), n-hexane (10.21 μg m^?3) and benzene (9.42 μg m^?3). According to the factor analysis, the evaporation of solvents used in the laboratories was found to be the dominant source.     

吹脱-捕集气相色谱法测定底质中易挥发性有机物

研究并建立了利用吹脱－捕集气相色谱法测定底质中易挥发性有机物的分析方法。该方法对底质中２５种易挥发性有机物进行测定。方法回收率在９６％－１０５％,最低检出浓度在０．３－１４．５μｇ／ｋｇ,变异系数在２．７％－５．３％。     

Incineration Techniques for Control of Volatile Organic Compound Emissions Part I. Fundamentals and Process Design Considerations

A review of incineration techniques for control of volatile organic compound emissions is presented in two consecutive issues of JAPC A. Part I presents an overview of the process including fundamentals and design considerations. Both thermal and catalytic incincerators are considered. Part II will present capital and annual operating cost estimates for both thermal and catalytic incinerator systems based on information received from a number of equipment manufacturers.     

Pilot Study of Enclosed Thermal Soil Aeration for Removal of Volatile Organic Contamination

During the winter and spring of 1986 sandy soils contaminated with volatile organic chemicals were successfully treated during a pilot study of an enclosed thermal soil aeration process at the McKin Superfund site in Gray, Maine. Excavated soil containing up to 3310 ppm of trichloroethylene (TCE) was fed into a large rotating drum and mixed at 300°F. Aerated soil was then solidified with cement and water and returned to the on-site excavation location. Exhausted air from the enclosed aeration process was treated in a baghouse, a scrubber, and a vapor phase carbon bed prior to atmospheric release. Continuous air monitoring for organic vapors and particulates took place at the site perimeter and for organic vapors at onsite locations. Techniques to minimize uncontrolled volatilization of organic chemicals from the soil during excavation and aeration and to control dust emissions were implemented. Results of this pilot study indicate that concentrations of volatile organic contaminants routinely were reduced to nondetectable levels and achieved site-specific soil performance targets established by the U.S. Environmental Protection Agency. The pilot study was conducted by Canonie Environmental Services Corporation and funded by private companies under order from EPA.     

Biofilter Treatment of Volatile Organic Compound Emissions from Reformulated Paint: Complex Mixtures,Intermittent Operation,and Startup

Abstract

Two biofilters were operated to treat a waste gas stream intended to simulate off-gases generated during the manufacture of reformulated paint. The model waste gas stream consisted of a five-component solvent mixture containing acetone (450 ppm_v), methyl ethyl ketone (12 ppm_v), toluene (29 ppm_v), ethylbenzene (10 ppm_v), and p-xylene (10 ppm_v). The two biofilters, identical in construction and packed with a polyurethane foam support medium, were inoculated with an enrichment culture derived from compost and then subjected to different loading conditions during the startup phase of operation. One biofilter was subjected to intermittent loading conditions with contaminants supplied only 8 hr/day to simulate loading conditions expected at facilities where manufacturing operations are discontinuous. The other biofilter was subjected to continuous contaminant loading during the initial start period, and then was switched to intermittent loading conditions. Experimental results demonstrate that both startup strategies can ultimately achieve high contaminant removal efficiency (>99%) at a target contaminant mass loading rate of 80.3 g m^?3 hr^?1 and an empty bed residence time of 59 sec. The biofilter subjected to intermittent loading conditions at startup, however, took considerably longer to reach high performance. In both biofilters, ketone components (acetone and methyl ethyl ketone) were more rapidly degraded than aromatic hydrocarbons (toluene, ethylbenzene, and p-xylene). Scanning electron microscopy and plate count data revealed that fungi, as well as bacteria, populated the biofilters.