OAR Box 1870 

Prepped by Ollie Stewart 

Document Number: 

25) ll-A-28 

Docket Number: 

A-90-19 

Printed 11/28/2008 7:05:04 AM Sheet 25 of 67 

P.1 
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• » 

Destruction of Air Emissions 

Using Catalyti c Oxidation 

Kn-fk'CWXy 

A-90-19 

ll-A-28 

PP8R-?1 J'» c' ' 

(U.S.) Environmental Protection Agency 

Research Triangle Park, NC 

May 88 

[ ] 

U.S. Department of Commerce 

National'Technical 'nformation Service 

Radian Library 
P.3 

Pddo-i 1 «**:><: 

EPA/600/D-8P/107 

May 1988 

DESTRUCTION OF AIR EMISSIONS USING CATALYTIC OXIDATION 

oy 

Michael Kosusko and Geddes Ramsey 

Air and Energy Engineering Research Laborarory 

U.S. Environmental Protection Agency 

Research Triangle Park, NC 27711 

EPA Project Officer 

.-lichael Kosusko 

AIR AND ENERGY ENGINEERING RESEARCH LABORATORY 

OFFICE OF RESEARCH AND DEVELOPMENT 

U.S. ENVIRONMENTAL PROTECTION AGENCY 

RESEARCH TRIANGLE PARK, NC 27711 

REPRODUCED BY 

U.S. DEPARTMENT OF COMMERCE 

National Technical Information Service 

SPRINGFIELD, VA. 22161 
P.4 

.££x2.<0±fX. 

SAC 

TECHNICAL REPORT DATA 

(Htast rttd lauruetiont on thi rtvtnt btfort completing' 

1. REPORT NO. 

EPA/600/D-88/107 

4. TITLE ANO SUBTITLE 6. REPORT DATS 

Destruction of /i r Emissions Using Catalytic Oxidatioq__Ma^_i988_ 

I . PSRPORMINO OROANIZATiON COOE 

I . PERFORMING OROANI2ATION NAME ANO AOORESS 

7. AUTHORS ) 

Michael Kosusko and Geddes M. Ramsey 

f. PSRPORMINO ORGANIZATION REPORT NO 

II 

See Block 12 

12. SPONSORING AGENCY NAMC ANO AOORESS 

EPA, Office of Research and Development 

Air and Energy Engineering Research Laboratory 

Research Triangle Park, NC 27711 

xmw:Ti ESSiQ* NO: 

/AS 

10. PRGORAM ELEMENT NO. 

rrrsfjrirxerTswiumu: 

NA 

13. TYPE OP REPORT ANO PERIOO COVERED 

Published paper 

14. SPONSORING AGENCY coo i 

EPA/600/13 

^.SUPPLEMENTARY NOTES A £ER L project officer is Michael Kososko. Mail Drop 61. 919/ 

541-2734. 

is. ASS »AC j^ e paper discusses key emission stream characteristics and h; zardous 

air pollutant (HAP) characteristics that affect the applicability of catalytic oxidation 

as an air pollution control technique in which volatile organic compounds (VOCs) and 

vapor-phase air toxics in an air emission stream are oxidized with the help of a catalyst. Design of catalytic systems for control of point source emissions is based on 

stream-specific characteristics and desired control efficiency. The application of 

catalytic oxidation to four types of air emission sources is discussed: groundwater 

stripping operations, graphics arts (heatset printing) facilities, flexographic printing plants, and latex monomer production. The characteristics of each emission are 

discussed along with the catalytic technology used to control it. In addition, several 

catalytic systems are identified for control of air emissions, along with information 

about their technology and their position in the market place. Finally, some rough 

economics are presented which compare catalytic oxidation, carbon adsorption, and 

thermal incineration systems. 

KEY WORDS ANO DOCUMENT ANALYSIS 

DESCRIPTORS 

Pollution Ground Water 

Incinerators Stripping 

Catalysis Graphic Arts 

Organic Compounds 

Volatility Flexography 

Toxicity Latex 

Activated Carbon 

19. DISTRIBUTION STATEMENT 

Release to Public 

b.lOENTIPISRS/OPEN (NOE O TERMS 

Pollution Control 

Stationary Sources 

Catalytic Oxidation 

Groundwater Stripping 

Heatset Printing 

19. SECURITY CLASS (ThURtport) 

Unclassified 

20 SECURITY CLASS (ThUpf) 

Unclassified 

c. COSAT I Field/Group 

13B 

07D 

07 C 

20M 

06T 

08H 

07A.13H 

14E.05F 

11J 

11G 

2 1 . NO. OP PAGES 

28 

22. PRICE 

PG}j 13. q C 

( P A Perm JJ10-I <t-71) 
/ '• 

P.5 

NOTICE 

This document has been reviewed in accordance with 

U.S. Environmental Protection Agency policy and 

approved for publication. Mention of trade names 

or commercial products does not constitute endorsement or recommendation for use. 

11 
P.6 

DESTRUCTION OF AIR EMISSIONS USING CATALYTIC OXIDATION 

by 

Michael Kosusko and Geddes Ramsey 

U. S. Environmental Protection Agency 

Air S Energy Engineering Research Laboratory 

A1r Toxics Control Branch 

Research Trianglo Park, North Carolina 27711 

ABSTRACT 

Catalytic Incineration s an air pollution control, technique 1n 

which volatile organic compounds (VOCs) and vapor-phase air toxics 1n an 

air emission stream are oxidized with the help of a catalyst. Design of 

catalytic systems for control of point source emissions Is based on 

stream-specific characteristics and desired control efficiency. This 

paper discusses the key emission stream characteristics and hazardous air 

pollutant (HAP) characteristics that affect the applicability of catalytic 

oxidation. 

The application of catalytic oxidation technology to four typos of 

air emission sources is discussed. These are: (1) groundwater stripping 

operations; (2) graphic arts facilities; (J) flexographic printing plants; 

and (4) latex monomer production. The characteristics of each of these 

emissions are discussed along with the catalytic technology used to control these emissions. 

In addition, several catalytic systems for control of air amissions 

are identified along with Information about their technology and their 

position in the market place. Finally, some rough economics are presented which compare catalytic oxidation, carbon adsorption, and thermal 

Incineration systems. 
P.7 

INTRODUCTION 

The most frequent approach to point source air emissions control 1s the 

application of add-on control devices. For organic vapors, these devices can 

be of two types: combustion and recovery. Applicable combustion devices are 

thermal Incinerators, catalytic incinerators, flares, and boilers/process 

heaters. Applicable recovery devices include condensers, adsorbers, and 

absorbers. The combustion devices are the more commonly applied control 

devices, since they are capable of high removal (I.e., destruction) efficiencies for almost any type of hazardous air pollutant (HAP). The removal 

efficiencies of the recovery techniques generally depend on the physical and 

chemical characteristics of the HAP under consideration. 

Applicability of the control techniques depends more on the individual 

emission stream under consideration than on the particular source category 

(e.g., degreasing vs. surface coating in the solvent usage operations source 

category). Thus, applicable control techniques for point source emissions 

are selected on the basis of stream-specific characteristics and desired 

control efficiency. The key emission stream characteristics and HAP characteristics that affect the applicability of each control technique are: HAP/ 

organics content, heat content, moisture content, flow rate, temperature, and 

molecular weight. 

Matching the characteristics of the stream under consideration with the 

useful '-anges of the control devices will help the user to identify those 

techniques that can potentially be used to control the emission stream. 

Catalytic oxidation, for example, 1s generally useful for concentrations of 

50 to 10,000 ppmv, if the total concentration 1s less than 25% of the lower 

explosive limit (LEL), and for flow rates of less than 100,000 scfm (170,000 

Nnw/hr'i. The 11st of potential applicable control techniques can then be 

narrowed further depending on the capability of the applicable control 

device, to achieve tne required performance levels. For example, catalytic 

incineration can achieve an expected controV efficiency of greater than 95% 

at total volatile organic compound (VOC) concentrations of greater than 100 

ppmv. Very little data regarding confol device removal efficiency for 

specific HAPs are available. Therefore, without actual source test data for 

a specific emission stream and control system, HAP removal efficiency Is 

generally assumed to equal total VOC removal efficiency (1). 

CATALYTIC OXIDATION TECHNOLOGY 

The topic of this presentation 1s catalytic Incineration, which 1s also 

called catalytic oxidation and catalytic destruction. Catalytic Incineration 
P.8 

1s an air polluticn control technique whereby VOCs and vapor-phase organic 

air toxics 1n an air emission stream are oxidized with tne help of a catalyst. 

A catalyst 1s a substance that accelerates the rate of a reaction at a given 

temperature without being appreciably changed during the reaction. Catalysts 

typically used for VOC incineration Include platinum and palladium. Other 

formulations are also used, Including metal oxides for emissions streams containing chlorinated compounds. 

A typical catalytic oxidation system with primary and secondary heat 

recovery 1s shown 1n Figure 1. Process air emissions, generally at ambient 

temperatures, are passed though the primary heat exchanger to recover heat 

from hot exhaust gases. If necessary, the emission stream 1s then preheated 

to catalytic oxidation temperatures 1n a natural-gas-f1red, or electric preheater before passing Into the catalyst bed. A small portion of the process 

air emissions 1s separated from the controlled strean and used as combustion 

air before primary heat exchange. 

The catalyst bed (or matrix) 1s generally a metal-mesh-mat, ceramic 

honeycomb, or other ceramic matrix structure designed to maximize catalyst 

surface area. Catalysts may also be 1n the form of spheres or pellets which 

may operate eithe.* 1n a T1"xed or fluidized bed configuration. Care must be 

taken that high preheat temperatures accompanied by the Increase 1n temperature due to combustion do not result 1n high operating temperatures In the 

catalyst bed. This could cause the catalyst bed to overheat and eventually 

lose its activity. 

Exhaust, gases then pass through the hot side of the primary heat exchanger, giving up heat to the Inlet stream. If the economics are favorable, 

secondary heat recovery 1s used. Recovered heat 1s often used for process 

heat or, 1n the case of printing operations, for dryer makeup air preheating. 

If the oxidized streams contain chlorii .ted compounds, caustic scrubbing may 

be required before the exhaust stream can be emitted to the atmosphere. 

The performance of a catalytic Incinerator 1s affected by several factors 

including: (a) operating temperature, (b) space velocity (reciprocal o' 

residence time), (c) VOC composition aid concentration, (d) catalyst properties, and (e) presence of polsons/'nMbltors in the emission stream. In 

catalytic Incinerator design, the Important variables are the operating 

temperature at the catalyst bed inlet and xhe space velocity. The operating 

temperature for a particular destruction efficiency 1s dependent on the 

concentration and composition of the VOC in the emission stream and the type 

of catalyst used. 

Space velocity 1s defined as the volumetric flow rate of the combined 

gas stream (1.«., emission stream + supplemental fuel • combustion air) 

entering the .•ta'yst bed divided by the volume of the catalyst bed. As 

such, space velocity also depends on the type of catalyst used. At a given 

space velocity, increasing the operating temperature at the Inlet of the 

catalyst bed Increases the destruction efficiency. At a given operating 

temperature, as space velocity 1s decreased (I.e., as residence time in tne 
HEATED AIR 

TO BUILDING 

EXHAUST 

TO ATMOSPHERE 

SECONDARY 

HEAT EXCHANGER AMBIENT MAKEUP AIR 

NATURAL 6AS 

COMBUSTION AIR BLCMER 

PREHEATER 

OXIDIZER EXHAUST 6AS 

PRIMARY 

HEAT EXCHANGER 

(701 EFFICIENCY) 

.CATALYTIC SYSTEM FEED 

CATALYST BED 

PROCESS FAN 

FROM EMISSION 

SOURCE 

PREHEAT BURNER M/tKEUP AIR 

(AFTER (2)1 

1 

Figure 1. Process flow sketch - catalytic oxidation system 
P.10 

catalyst bed increases), destruction efficiency Increases. Catalytic 1nciner.tors can achieve overall VOC destruction efficiencies up to about 98% and 

HAP destruction efficiencies up to about 95% with space velocities 1n the 

range 30,000 to 100,000 gas hourly space velocity (GHSV) (3,4,5). However, 

the greater catalyst volumes and/or higher temperatures required for high 

destruction efficiencies (i.e., 99%) may make catalytic incineration 

uneconomical. 

The performance of catalytic incinerators 1s sensitive *.o pollutant 

characteristics and process conditions. Therefore, 1n there ntroductory 

discussions, 1t 1s assumed that the emission stream 1s free, from poisons/ 

inhibitors such as phosphorus, lead, bismuth, arsenic, antimony, mercury,. 

Iron oxide, tin, zinc, sulfur, and halogens. It 1s also assumed that the 

fluctuations 1n process conditions (e.g., changes in VOC content) are kept to 

a minimum as are liquid or solid particles that could deposit on the catalyst 

and form a coating, thereby reducing the catalyst's activity by preventing 

contact between the VOCs and the catalyst surface. Additionally, catalyst 

U f e 1s limited by thermal aging and by loss of active sites by erosion, 

attrition, and vaporization. With proper operating tenperatures and adequate 

temperature control, there processes are normally slow, and satisfactory 

performance can be maintained for 3 to 5 years before replacement of the 

catalyst 1s necessary. 

The data necessary to perform design calculations consist of the emission 

stream characteristics listed below and of the HAP control level as determined 

by the applicable regulations (1). These data are: 

o Maximum Flow Rate 

o Temperature 

o Heat Content 

o Oxygen Content 

o Moisture Content 

o Required Destruction Efficiency 

[scfm (Nm3/hr)] 

[°F (°C)] 

[Btu/scf (kcal/Nm3)] 

(%) 

(%) 

(%) 

If dilution air is added to the emission stream upon exiting the process, 

tne data that will be used in the calculations are the resulting characteristics aftar dilution. 

In general, catalytic incineration 1s applied to dilute emission streams. 

If emission streams with high VOC concentrations [I.e., heat content above 10 

Btu/scf (89 kcal/Nm3) for air •' VOC mixtures] are treated by catalytic 

incineration, they may generate enough h.at upon combustion to deactivate the 

catalyst. Therefore, dilution of the emission stream to heat contents of 

less than 10 Btu/«cf with air 1s necessary to reduce the concentration of the 

VOCs (1). 

Table 1 presents suggested values and limits for the design variables of 

a fixed bed catalytic incinerator system to achieve a given destruction 

efficiency. For specific applications, other temperatures and space velocities may be appropriate depending on the type of catalyst employed and the 
P.11 

emission stream characteristics (I.e., composition and concentration). For 

example, the temperature of the flue gas leaving the catalyst bed may be 

lower than 1,000 °F (538 °C) for emission streams containing easily oxidized 

compounds and still achieve the desired destruction efficiency. Note that 

the destruction efficiency for a given compound may vary depending on whether 

the compound 1s the only VOC 1n the emission stream, or 1t 1s part of a 

mixture of VOCs (3). 

Table 1. Catalytic Incineration System Design Variables (4,5,6) 

Required 

destruction 

e/f1ciency 

(t) 

Hlnimum 

temperature 

at the catalyst 

bed Inlet 

[

8

F(°C)] 

Temperature 

at the catalyst 

bed outlet 

(Minimum-Maximum) 

[°F(8C)] 

Space 

velocity 

(hr-1) 

90 600 (316) 1,000-1,200 (538-649) 40,000 

95 600 (316) 1,000-1,200- (538-649) 30,000 

Supplementary fuel !s added to the catalytic incinerator system to 

provide the heat necessary to bring the emission stream up to the required 

catalytic oxidation temperature for the desired level of destruction efficiency. For a given Inlet temperature, the quantity of supplementary heat 

needed is provided by: (a) the heat supplied from the combustion of supplementary fuel, (b) the sensible heat contained 1n the emission stream as it 

enters th. catalytic incinerator system, and (c) the sensible heat gained by 

tha emission stream through heat exchange with hot flue gases. If recuperative heat exchange is not practiced at a facility, then Item (c) will be 

zero. 

CASE STUDY 1: AIR STRIPPING OF GROUNDWATER 

Air stripping of groundwater has been shown to be an efficient and cost 

effective method of removing VOCs from groundwater and soil. The removal of 

dissolved fuel fractions and chlorinated solvents at efficiencies 1n excess 

of 95% has been demonstrated on several occasions. Unfortunately, these contaminants are transferred to the air where they may continue to pose an 

environmental and health threat. Regulation of such emissions has already 

considered 1n many states Including Michigan and California. 

The appHcab Ht y of catalytic oxidation to the control of groundwater 
stripping gaseous emissions will be reviewed with special attention given 

to system designs and case histories. The variety of contaminants and catalyst poisons encountered 1n stripping operations will alio be reviewed. 

Presently, few options are available for the control of groundwater air 

stripping emissions. Vapor-phase carbon adsorption and thermal Incineration 

are the two treatment methods which are best established. These technologies 

have some disadvantages. Adsorption merely transfers the contaminant to a 

solid phase, wnich 1n turn requires disposal or regeneration. Regeneration 

with steam results in a contaminated waste water stream which requires treatment and disposal. Thermal Incineration may be expensive, since 1t requires 

a substantial energy Input to destroy dilute gas-phase contaminants. Catalytic oxidation 1s establishing Itself as a new alternative to these more 

established technologies. Like thermal Incineration, 1t Is an ultimate disposal method, but since 1t operates at much lower temperatures, the energy 

costs are also lower. 

A hypothetical system with catalytic destruction of air stripping 

effluents is pictured In Figure 2 (7). A1r 1s countercurrently contacted 

with a contaminated water stream. Most volatile compounds are transferred to 

the air stream, and the water receives a final cleanup In the liquid polishing 

step before disposal. The catalytic destruction of organic emissions in the 

air stream differs from other catalytic pollution control applications in 

several important aspects. First, the concentration of the contaminants in 

the gas phase is quite low, in most cases less than 100 ppmv. Second, tne 

humidity levels are unusually high since the air stream 1s saturated coming 

off the stripping unit. Third, a wide variety of contaminants and mixtures 

ranging from chlorinated compounds and soluble fuel fractions to pesticides 

and polychlorinated biphenyls may be in any groundwater source. Finally, the 

air stream exiting a groundwater stripper may have high concentrations of 

mineral aerosols and catalyst poisons (e.g., hydrogen sulfide) that will 

shorten catalyst Ufe . All of these factors make the design and Implementation of catalytic treatment uncertain. 

The emissions from air stripping units may consist of a complex mixture 

of reactants including both fuel and solvent fractions. A typical example of 

an air stripping off gas stream 1s shown 1n Table 2. This table lists the 

concentration of selected contaminants emitted from a pilot air stripping 

unit at Wurtsmith Air Force Base in Mich<gan (8). Here, no individual contaminant exceeds 70 ppmv, but the cumulative total exceeds 170 ppmv. 

The energy burden of heating a cold, water-laden air stripping effluent 

stream should be lower for a catalyst system than for thermal Incineration, 

but it still represents a considerable operating cost. The air from most air 

stripping units can be considered to be saturated with water (100% relative 

humidity). This corresponds to an absolute water vapor concentration of 

between 0.8 and 3.1% In the exit str.am. The action of bubbles 1n the stripping unit also produces a large amount of liquid aerosol. The carryover of 

liquid water in the form of small, droplets and aerosol represents an additional large heat burden on any catalyst bed and should be minimized by the 

use of demisters or filters if possible. Aerosol removal has an additional 
00 

GROUNDWATER INLET RIPPER KE

D TOWE

R AI

R ST 

3 

OL 

INLET AIR — 

lit 

0000000 4 

,v.v.\v. 

v,v,v>v 

0000004 0 

.v.w.w 

0000400 4 

*:*:*:• 

*:*>#> 

• 

TT 

DEI yiiST 

AIR EFFLUENT 

± 

DEMISTER 

EFFLUENT 

SUPPLEMENTAL FUEL~ 

SCRUBBER 

CATALYST 

BED 

^ PLENUM 

^ " ^ CHAMBER * • • * • rl»i • • • • 

::::t::;t:::: 

l-jiijiiHitj !j!::ii::::ii 

PlPi 

si::i::::t::: 

SCRUBBER 

—*>E.FLUENT 

CATALYTIC INCINERATOR 

• WATER EFFLUENT 

LIQUID POLISHING STEP 

Figure 2. System configuration for catalytic destruction 

of air stripping emissions. 

TJ 

Eo 
P.14 

advantage, in that mineral or biological matter which might foul end deactivate the catalyst bed 1s also removed. 

Table 2. Typical Organic Concentrations in 

Air Stripping Overhead (8) 

Compound 

Pentane 

Cyclohexane 

Methyl cyclopentane 

2,3-D1methyl butane 

Trichloroethylene 

Benzene 

Ethyl benzene 

Cumene 

Mixed xylenes 

Total 

Concentration 

in gas phase 

(ppmv)a 

42.4 

66.1 

7.7 

1.6 

17.9 

9.2 

8.3 

3.4 

21.3 

177.9 

Calculated at a gas/liqu1d ratio of 42/1 for l-1n. 

(2.5-cm) Pall rings. 

The high concentration of water vapor 1n the emission stream represents 

a major deference between this application of catalytic control and other 

more t^ical applications. As of now, no firm basis exists to predict the 

behavior of non-halogenated hydrocarbon oxidation in the presence of water. 

On the other hand, the effect of water on the catalytic destruction of 

chlorinated compounds is generally thought to be beneficial. The most easily 

treated products of this process are hydrochloric ad d (HCl), carbon dioxide, 

and water; however, some solvents such as trichloroethylene (C2HCI3 do not 

have stoichiometric amounts of hydrogen to allow complete reaction of the 

chlorine to HCl. i'or those compounds, water may serve as this hydrogen 

source, or may mere'y favorably alter the reaction thermodynamics. Other 

hydrogen sources such as methane or propane may also be beneficial 1n promoting 

HCl formation. As with the non-halogenated hydrocarbons, a clearer understanding of the catalytic chemistry Is essential to understanding the role of 

water vapor. 

As a further complication, many contaminated groundwater sources may contain mixtures of hydrocarbons and halogenated compounds. Laboratory and 

pilot studies have found significant mixture effects for oxidation of hydrocarbons, chiefly 1n the form of Inhibition (9,10). This means that the catalytic oxidation of a given compound Is generally negatively Impacted by the 

presence of mixtures, and higher catalyst bed operating temperatures may be 

necessary to achieve adequate destruction. Information on mixture effects 

for halogenated compounds 1s extremely limited. 
P.15 

Catalysts exposed to the air stripping effluent are subject to deactivation from several sources: fouling, thermal degradation, polsoninq, and 

catalyst volatilization. The catalyst bed may plug or become encrusted, 

thereby losing Its effectiveness due to dissolved salts and mineral matter 

1n the air stripping off gases. As mentioned previously, removal of aerosols 

pricr to the catalyst unit may alleviate this problem. If the catalyst bed 

1s operated at high temperaturi-s [greater than 1,110 °F (600 °C)] for prolonged 

periods, sintering of active noble metals may occur also resulting in loss of 

activity. Groundwater also often contains significant amounts of readily 

strlppanle compounds, such as hydrogen sulfide (H2S), that may poison -.he 

catalyst surface by adsorbing and blocking active sites. Higher operating 

temperatures may remove some of these poisons, but sintering may then become 

a problem. Finally, some reactants, especially halogenated compounds, may 

chemically bond with the active catalyst and subsequently volatilize from the 

surface. The loss of catalyst associated with this vaporization process 

Inevitably results 1n lower catalyst efficiency. 

A recent EPA report (11) identified 177 air strippers 1n the United 

States. Of these, 17 are equipped with air emission controls. Of the 17 

facilities, 1 uses a catalytic Incinerator, 2 have open flares, 2 have thermal 

Incinerators, and 12 have granular activated carbon adsorbers. Installation 

of the ?.ir control device was required by the governing state at 9 of these 

17 sites. 

The catalytic Incinerator Identified 1n Reference 11 1s located at the U.S. 

Coast Guard Base In Traverse City, Michigan. This air stripper system began 

operation in 1985. The catalytic Incinerator was Included 1n the Initial 

design and installation of the air stripping system. The air stripper Installed at this site 1s a rotary high-gravity air stripper which achieves 

high removal efficiencies at lower air to water ratios than packed towers. The 

lower air flow for this type of air stripper results in higher pollutant 

concentrations in the air stripper exhaust. The catalytic Incinerator at 

Traverse City was installed for destruction of benzene, toluene, and xylene 

stripped from the groundwater. The catalytic oxidation unit 1s designed for 

a flow of ?,000 scfm (3,400 Nm3/hr) and operates at 500 to 600 °F (260 to 320 

°C). The design efficiency for this catalytic Incinerator was 90% (11). 

However, no performance data are available (12). The estimated Installed 

cost for the catalytic unit is $198,500, and annual operating costs for the 

2,000 scfm (3,400 Nm3/hr) unit are $95,920 (based on third quarter 1986 data) 

(11). 

A catalytic incinerator has been built for control of organic air 

emissions from air stripping of groundwater 1n two additional cases. The 

U.S. Air Force has installed a fluidized bed, nonprecious metal catalyst 

system for control of trichloroethylene and 1,2 dichloroethylene air stripping 

emissions at Wurtsmlth A1r Force Base 1n Michigan. The treated air flow 1s 

1,100 scfm (1,870 Nm3/hr) at an operating temperature of 900 °F (4o0 °C). 

Without auxiliary equipment, it 1s reported that the stripper cost $70,000, 

while the catalyst system cost $126,000. Catalyst life is expected to be 2 

10 
years with catalyst aging being the result of attrition of the catalyst 

pellets. Catalyst replacement cost has been quoted at $1,200. Performance 

data are not yet available (12). 

The destruction performance achieved during pilot scale testing of an 

air stripper exhaust stream containing benzene and toluene 1s presented 

graphically In Figure 3 (13). The location of these tests was not Identified. 

The Incoming air from the stripping unit contained less than 10 ppmv total 

organics. 

CASE STUDY 2: GRAPHIC ARTS 

Dryer emissions from the graphic arts (heat set web offset printing) 

Industry are primarily composed of hydrocarbon solvent, alcohol (1f used), 

water vapor, and the byproducts of burner combustion (carbon dioxide and 

traces of unburned natural gas). Eventually all of these materials are exhausted from the dryer resulting in three pollution problems which need to be 

addressed: "smoke" or opacity, odor, and VOCs. The "smoke" observed 1s actually 

condensing ink solvents and water vapor. The odor 1s a function of the 

solvents and resins used. Tne organic compounds are the hydrocarbon solvents, 

alcohol, and unburned natural gas. A pollution control device must deal with 

all three of these problems to be effective. 

Typical Ink solvents used 1n the web offset industry are petroleum 

fractions distilled from crude oil and are similar to No. 2 fuel oil. These 

solvents typically boil in the range of 440 to 600 °F (225 to 315

 8 C) and are 

generally composed of approximately 85% aliphatic, 10% aromatic, and 5% 

olefinic hydrocarbons. Carbon numbers range from C9 to approximately C20 

with the largest concentration in the area of C14. A typical molecular 

weight for these solvents is 210, and they typically have a net heating value 

of 19,950 Btu/lb (11,080 kcal/kg). The lower explosive limit (LEL) for a 

solvent of this type is approximately 0.455% by volume at 300 °F (150 °C)(14). 

A second component of web offset dryer exhaust 1s often Isopropyl 

alcohol. Used in the fountain solution, this very volatile material is 

carried with the web into the dryer where almost all 1s evaporated. It 1s 

\iery difficult to measure the amount of alcohol which does reach the dryer 

because a percentage of the alcohol escapes into the pressroom as fugitive 

emissions. Recent advances in the use of less volatile alcohol substitutes 

have greatly reduced the volume of alcohol used by printing plants. 

One option for control of web offset emissions 1s catalytic incineration. Catalytic incinerators can be configured in the same manner as thermal 

incinerators with the use of primary heat exchangers to preheat the solventladen exhaust to the temperature necessary for catalytic oxidation. In 

addition, a secondary heat exchanger can be added as In Figure 1 to provide 

heated makeup air to the dryer. 

11 
99 

£ 98 

c 

to 

Ul 

c 

o 

o 

s 

M 

0) 

O 

97 

96 

D Benzene 

O Toluene 

95. 

I 1 

175 200 225 250 275 

Temperatrjre (°C) 

300 325 

Figure 3. Destructlot efficiency of a pilot scale catalytic Incinerator for 

benzene and foluene In air stripper exhaust. 
If, 1n the printing process, both the Ink coverage is heavy enough and 

press speed 1s high enough, then the catalyst preheat burner may be able to 

shut off, allowing the unit to run with only the oxidation of Ink solvent as 

a source of energy. This mode of operation presents the possibility for substantial energy savings. In addition, when heated makeup air is returned tc 

the dryer, the need for fuel at the dryer is reduced. Alternatively, 1f the 

heated air 1s used to drive another recovery device (absorptive chi^er, 

building heating and ventilating system, etc.), the auxiliary energy required 

to fuel that device would also be reduced. 

Catalytic incineration does, however, suffer from a number of disadvantages in this application. Heat-up times are as long for catalytic units as 

for thermal units due to the large physical mass of catalyst which must be 

heate. to the proper oxidation temperature. This disadvantage can be overcome to some extent. By incorporating an automatic damper, the system can be 

maintained in the "ready" mode wltn a minimum energy requirement. The cost 

of catalyst can be substantial causing the Initial capital Investment for a 

catalytic system to be from 15% to 30% higher than for an equivalent thermal 

system. Catalyst Uf e may vary from 1 to 5 years or more depending on 

the composition of the catalyst, as welt as operating and process variables 

(14). 

In the graphic arts Industry, the catalyst in catalytic Incinerators 

should be monitored on a regular basis because 1t is susceptible to contamination by phosphorus (phosphate buffers) from fountain solutions, silica from 

silicone gloss-enhancer sprays, or chlorides from chlorinated solvents or 

blanket wash solutions. The precious metal catalyst Is not poisoned by 

sulfur, but base metal catalysts are rapidly deactivated by sulfur In this 

type of application (15). 

Phosphorus and silica accumulate most rapidly on the leading edge of the 

catalyst bed and deactivate the catalyst by masking the precious metals. 

Both phosphorus and silica bond to either the alumina substrate or alumina 

washcoat. Because of phosphorus and silica poisoning, TEC Systems, a major 

supplier to the printing Industry of dryers and ancillary equipment Including 

catalytic Incinerators, has gone to bead type catalyst beds with low space 

velocities (about 7,000 to 8,000 GHSV) (15). With deeper catalyst beds, the 

leading edge of the catalyst tends to collect the poisons and thus protects 

the catalyst beads deeper In the bed. Catalyst beds with high space velocities 

(near 30,000 GHSV), such as monolith catalysts, often require frequent cleaning, sometimes as often as every 3 months. 

Chloride poisoning 1s much less common than phosphorus or silica poisoning; however, since 1t reacts directly with the precious metals, chloride 

deactivates the catalyst at much lower concentrations. Three potential 

sources of chloride poisoning are fire extinguishing systems, refrigeration 

systems which utilize fluorocarbons such as trlchlorotrlfluoroethane, 

and chlorinated hydrocarbon solvents (15). 

In some cases, TEC Systems has found that a catalyst unit may fall a 

compliance test even though the catalyst is in good shape (15). Failures of 

13 
P.19 

this nature have been traced to cracked heat exchangers, low catalyst levels, 

abnormally low incineration temperatures, leaking bypass dampers, and erroneous testing. 

CASE HISTORY 3: FLEXOGRAPHIC PRINTING PLANT 

A metal oxide catalyst In a fluidized bed configuration has been applied 

to a flexographic printing plant 1n Massachusetts (2). In •nany ways, this 

use 1s similar to the graphic arts application discussed 1n Case 2. The 

exhaust fumes from 10 flexographic printing drying ovens containing 120 lb/ 

hr (55 kg/hr) of VOC, 5 lb/hr (2.3 kg/hr) of silicones, and trace amounts of 

chlorinated hydrocarbons are controlled using catalytic oxidation. However, 

since the catalyst surface 1s continually renewed by abrasion 1n the fluidized bed, the problem of masking the catalyst surface with silicones is 

avoided. The use of a metal oxide catalyst avoids the problem of chlorine 

poisoning. Massachusetts' environmental emission regulations require at 

least 95% capture or destruction. 

The system was Installed 1n October 7.986. Operating conditions are 

shown in Table 3, and are typical of those used for easily combusted emissions. The vendor states that the tested efficiency was 1n excess of 99%. 

This high destruction efficiency 1s attributed to operation at 73% of design 

air flow rate. Decreased flow (hence decreased space velocity) increases 

destruction efficiency. The plant operates 24 hrs/day, 5 days/wk, and 260 

days/yr. The incineration system also Includes a 70% thermally efficient 

self-recuperative plate type heat exchanger for building heating. Design 

conditions are shown on the flow sketch of Figure 4. 

Table 3. Operating Conditions for Catalytic Control of a Flexographic 

Printing Plant (2) ~ 

Air Flow Rate 11,000 scfm 18,700 Nm3/hr 

(Design Value) 15,000 scfm 25,500 Nm3/hr 

VOC Loading 3 to 6 % of LEL 

(Fuel Value) 1.5 to 3.1 Btu/scf 13 to 28 kcal/Nm3 

Bed Inlet Temperature 700 °F 370 'C 

Bed Outlet Temperature 775 to 850

 #F 415 to 455 °C 

Catalyst Pressure Drop 10 1n. water 18.7 mm Hg 

Fuel Consumption 0.451 xlO^Btu/hr 114,000 kcal/hr 

The cost of the catalytic incinerator including the catalyst and process 

fan but not Including the cost of heat exchangers was $133,430. The annual 

operating cost for fuel 1s $14,071/yr at an energy cost of $5.00/106Btu 

($0.00002/kca1). This value does not include any credit for building heating 

cost* *hich were cut by 50%. Catalyst coses are $5,377/yr. 

14 

/ 
HEATED AIR 

TO BUILDIHO 

t EXHAUST 

TO ATMOSPHB€ 

SECONDARY 

HEAT EXCHANGER AMBIENT MAKEUP AIR 

PSEHEATER 

669 °F(354 °C) 

NATURAL 6AS 

OXIDIZER EXHAUST SAd 

FfllHAflY 

HEAT EXCHANGER 

r70I EFFICIENCY! 

CATALYTIC SYSTEM FEED 

COMBUSTION AIR BLOWER 

PREHEAT BURNER MAKEUP AIR 

EMISSION 

SOURCE 

(AFTER (2)1 

NATURAL GAS FUEL 

1.010 Btu/scf (8.990 kcal/N_3) 

2 pilg (14 KPa) 

10.14 icfa (17.23 Na3/hr) 

0.615x106 Btu/hr (155.000 kcal/hr) 

PflOCESS FAN S SYSTEM FEED 

15.000 «Cf• 

17.972 Kfa 

175 °F 

3.1 Btu/aef 

(2S.495 M3) 

(30. 530 a3) 

(79 °C) 

(27.6 kcal/N_3) 

COMBUSTION AIR BLOWER OXIOIZER EXHAUST GAS 

688 ecfe 

640 acfa 

175 °F 

(1.169 N»3/hr) 

(1,427 _3/hr) 

(79 °C) 

13.010 stfa 

24.160 atfa 

377 °F 

(23.500 Na?) 

(41.050 t3) 

(192 °C) 

Figure 4. Catalytic oxidation system - typical 

operating conditions. 

15 
P.21 

The vendor also calculated costs for a thermal Incinerator operating at 

11,000 scfm (18,700 Nm3/hr) with the same heat recovery. Fuel costs were 

estimated at *159,931/year at $5.00/106Btu ($0.00002/kcal). The exit temperature of the incinerator was estimated as 1,400 °F (760

 8 C)(2). 

CASE STUDY 4: LATEX MONOMER PRODUCTION 

For many years, one of the accepted methods of oxidizing gaseous hydrocarbon emissions has been by thermal incineration. This became the obvious 

choice when dealing with carcinogenic chlorinated hydrocarbon emissions; 

however, with 2,200 °F (1,200 °C) oxidation temperatures and 2-sec dwell 

times, incinerators became very large and the fuel costs excessive. The 

alternate choice was catalytic oxidation; however, the catalyst was easily 

po1<or:ed and tne unit made Ineffective. ARI Technologies has introduced a 

catalyst system which tnay claim can complete the reaction at an average bed 

temperature of 700 °F (370 °C) while achieving conversion efficiencies 1n 

excess of 99.99% (2). 

One difficult application of chlorinated hydrocarbon emissions control 

1s the manufacture of latex monomers. Being a typical batch operation, the 

concentration of chlorinated hydrocarbons varies widely from a heat content 

of 4 to over 300 Btu/scf (36 to 2,700 kcal/Nm3), which results 1n a potential ttfliperature rise across the catalyst of 200 to 1,500 °F (95 to 815 T) . 

During periods of very high concentrations, the temperature rise across the 

catalyst bed is kept within a reasonable range by the addition of dilution 

air. 

At the present time, five plants are operating successfully using 

catalytic Incineration as the control technology of choice. The range of 

operating parameters for a typical 4,000 scfm (6,800 Nm^/hr) catalytic 

incineration system 1s shown 1n Table 4. Note the wide range of dilution 

air rates needed to compensate for tne heat content of the process gas and the 

need fcr caustic scrubbing for control of hydrochloric ad d (HCl) emissions. 

The hit > conversion efficiency may be possible, If the chlorinated hydrocarbon is vinyl chloride, based on laboratory results which seem to Indicate 

that vinyl chloride combustion goes to completion below 700 °F (370 °C)(16). 

16 
Table 4. Operating Condition, for Catalytic Control of Latex Monomer 

Production Emissions (2) 

( Chlorinated HC Gas Flow 50 to 335 scfm 85 to 570 Nm3/hr 

| Inlet Temperature 700 °F 370

 8 C 

[ Heat Content 4.4 to 225 Btu/scf 39 to 2,000 kcal/Nn3 

Fuel Gas Consumption 0.9 to 3.0 scfm 1.5 to 5.1 Nm3/hr 

Dilution A1r Flow 60 to 3,000 scfm 100 to 5,100 Nn\3/hr 

Cooling Water Rate 110 to 1,000 gph 415 to 3,800 1/hr 

Caustic Addition Rate 0 to 150 gph 0 to 570 1/hr 

Water & Caustic to Drain 65 to 750 gph 250 to 2,850 1/hr 

Stack Temperature 95 to 160 "F 35 to 70 °C 

Conversion Efficiency 99.999% 

The cost of a typical 4,000 scfm (6,800 Km3/hr) system Including the 

major Items of equipment shown 1n Figure 4, *ater and caustic manifolds, 

controls and control panel, catalyst and service platforms is $350,000 to 

$400,000. The unit, which Is preassembled during fabrication, can be installed in the field 1n approximately 7 days ?.t an assembly cost of approximately $25,000. The operating costs of the system are a function of the 

chlorinated hydrocarbon concentrations and .he Individual plant operating 

procedure and can only be calculated based on a specific application (2). 

CATALYTIC UNITS FOR CONTAMINANT REMOVAL 

There are several commercial catalytic units now on the market in this 

country, and many others in Europe. Hov/ever, to our knowledge, there is 

experience with only three of these in conjunction with an air stripping 

unit. Most of these units are now used for controlling emissions from solvent stripping operations, paint spray booths, and similar Industrial operations where concentrations of reactants are much higher than air stripping 

emissions. Several of the commercially available catalytic Incinerators have 

been identified and are described below: 

1. ARI: This fluidized bed catalytic Incinerator was developed 1n the 

early 1970s. Developed jointly by Air Resources, Inc. (ARI) and Harshaw 

Chemical Company, this technology has been 1n commercial use since 1975 

and Is being marketed oc a turnkey basis (16). The catalyst 1s a 

nonprecious metal disposable pellet. The fluidized design is especially 

good 1n that 1t overcomes carbon fouling (masking) problems. The moving 

catalyst bed allows masked catalyst to move to higher temperature zones 

In the bed, thereby oxidizing the masking material. Other mineral 

deposits (e.g. sulfur, phosphorus, silicon, salts) which may coat 

the surface are removed from the catalyst pellet by attrition 1n the 

fluidized bed. This results in a catalyst life of about 2 yocrs. 

17 
P.23 

Approximately 50 of these fluidized bed units are being used for VOC 

control. Of the 50 significant portion are used for control of chlorinated hydrocarbons. 

ARI and Union Carbide have recently cooperated to develop a new system 

employing ARI fluidized bed catalyst technology and Union Carbide molecular sieve adsorbent expertise. Their system uses S1l1cal1te adsorbent 

to preconcentrate organic missions before they are fed to the catalytic 

unit. The combined system is said to be more cost effective than catalytic destruction alone since the catalytic unit can be downscaled by a 

factor of 10 or more (2). 

2. CE A1r Preheater: CE markets both thermal and catalytic Incinerator 

systems 1n sizes ranging from 2,000 to over 100,000 scfm (3,400 to 

170,000 Nm3/hr). Their catalyst, supplied by Johnson-Matthey, 1s 

platinum deposited or a stalnles* steel honeycomb. CE A1r Preheater has 

Installed 17 catalytic Indnera*;. -^s as of 1988 (17). 

3. Dedert Corporation: Dedert market1... VTOX" catalytic Incinerator for 

Haldor Topsoe A/S, a Oanlsh company specializing in catalysts. It 

features a non-noble metal catalyst resistant to chlorine, sulfur, and 

phosphorus compounds 1n both monolithic and pelleted forms. They market 

a special "AOOX" unit for low concentrations (less than 250 ppmv), and 

another, named "REGENOX," for "dirty" streams. Many of these units are 

in place for manufacturing and Industrial processes. 

4. Engelhard (Torvex): Since the early 1980s, this system has been marketed by the Engelhard Corporation. Complete systems are available 1n 

sizes ranging from less than 1,000 to 70,500 scfm (1,700 to 120,000 

Nm3/hr). The'r catalysts consist of precious metal deposited on 

ceramic honeycombs. Between 1976 and 1988, the vendor supplied about 

250 complete catalytic Incinerator systems In the U.S. and over 1,000 

in Japan and has retrofitted about 210 thermal incinerators with catalyst. 

5. Groundwater Technology, Inc.: Groundwater Technology provides complete 

groundwater cleanup services. As Such, they have entered the area of 

cleanup of air emissions from these operations. They report Installation of their first catalytic conversion unit. The catalyst was 

obtained from Johnson-Matthey and consists of platinum on a metal substrate. Effective destruction of fuel mixtures stripped from groundwater has been dt*d (13). 

6. Johnson-Matthey: A major manufacturer of catalysts and other materials 

employing precious metals markets a variety of self contained catalyst 

treatment systems for removal of organic compounds from gaseous emissions. Their "Honeycat" unit may be fitted with either a ceramic or metal 

honeycomb catalyst tupport. Inexpensive units are marketed for treatt of low volume streams. 

18 
P.24 

7. 

8. 

Met-Pro Corporation: Formerly Oxy-Catalyst, this company markets both 

thermal and catalytic Incineration systems and carbon adsorption systems. 

They employ a wide range of catalysts Including both previous and nonprecious metals deposited on a monolithic or pelleted support. They 

have installed over 20(1 catalytic incinerator systems throughout the 

United States and some foreign countries (18). 

TEC Systems: This subsidiary of W.R. Grace manufactures and markets 

catalytic Incinerator systems that utilize both granular and monolithic 

noble metal catalysts on alumina substrates. Their granular catalyst 1s 

manufactured by Davison. These Incinerators have been effectively used 

to control VOC emissions from a number of Industrial processes, primarily 

in the printing Industry (15). 

9. Ultrox 

based 

ogy. 

chlorl 

air ml 

Irradi 

phase, 

pass 1 

temper 

Ultrox International continues to develop and market a system 

on a combined ultraviolet (UV)/ozone/catalyt1c oxidation technol" 

When used for water treatment, the 

nated hydrocarbons is pumped Into a 

xture 1s bubbled through the wate:-. 

ated with UV light. In addition to 

a portion of the 'tydrocarbons are 

nto a UV catalytic reactor where 

atures slightly above ambient. 

groundwater contaminated with 

reaction tank where an ozone/ 

This bath 1s simultaneously 

the oxidation in the aqueous 

stripped from the water and 

further oxidation occurs at 

In general, a catalyst with high activity at low temperatures 1s desirable, hut enough heat must be supplied to effect complete destruction. However, extremely high temperatures [greater than 1,380 "F (750 °C)] may actually produce additional partial reaction products. Basically, this means 

that a minimum operating temperature of at least 660 °F (350

 9 C) should be 

employed with currently available catalysts. Most catalyst units, regardless 

of the catalyst bed structure, use a preheating unit to attain these temperatures. This preheater may be electric or an open flame type. The open flame 

type is generally powered by natural gas or propane, and may accomplish a 

significant degree of destruction by Itself (10). These preheaters are used 

with iiost of the reactors now available commercially, 1n both fixed and 

fluidized bed designs. 

ECONOMICS 

The Control Technology Center (CTC) report summarizes control costs and 

efficiencies for carbon adsorption at four air stripper sites (11). It then 

completes estimates of control costs at these sites for thermal Incineration 

and catalytic oxidation at 98% and 95% efficiency, respectively. 

19 
P.25 

Table 5 summarizes these estimates. It may be noticed from this table that 

the annualized costs of control Increase as a function of air flow rate for 

all of the systems. The most rapid Increase 1n cost 1s for thermal incineration, with catalytic oxidation being twice as cost effective for the 19,200 

s.-.fm (32,600 }tm3/hr) unit. This emphasizes the energy savings mentioned 

previously for catalytic systems. Carbon adsorption still has a more favorable operating cost; however, for the operating systems considered 1n the CTC 

report, the expected control eff1c1.nv.1es for thermal and catalytic Incineration (more than 95%) were much greater than the observed efficiencies for 

adsorption (70 to 90%). Of course, carbon adsorption can attain higher 

control efficiencies with increased bed size or decreased relative humidity 

of the emission stream. However, such changes will result 1n Increased 

capital and annualized operating costs. A cost analysis for an existing high 

efficiency (greater than 95%) carbon adsorption system 1s not presently 

available. The tradeoffs between control efficiency and costs must be made 

in light of the seriousness of the contamination threat. 

20 
Table 5. Summary of Air Strutting Exhaust Control Systeas (11) 

Site A Site B Verona Nell field Plainfield 

Conteainants 

Concentration (ppbw) 

Trichloroethylene 

(4.000) 

Trichloroethane 

(300) 

Chlorofor* 

(1.500) 

Water FloHrata (gpa)* 

Air Flow-ate (scfa)* 

Reaoval efficiency (%) 

Control OctIons: 

1.400 

0.000 

99 

Carbon Adsorption 

Control efficiency (*) -eo 

Installed cost (S) 150.000 

Oirect operating cost (S) 50.400 

Total annualized costs ($) 96.400 

Tneraal Incineration 

Control efficiency (%) 98 

Installed cost (S) 318.000 

Oirect operating cost (S) 432.000 

Total annualized costs (8) 492.000 

Catalytic oxidation 

Control efficiency (*) 95 

Installed cost (8) 307.000 

Oirect operati.vj cost (8) 210.000 

Total annualized costs (8) 269.000 

155 

1.300 

99.9 

not reported 

152.000 

31.300 

77.800 

98 

187.000 

86.800 

129.000 

95 

135.000 

51.600 

86.100 

Ethylene dichloride 

(5) 

Trichloroethane 

(12) 

0 i ch1oroethylene 

(10) 

Trichloroethylene 

(1) 

Perchloroethylena 

(10) 

1.900 

5.500 

99.9 

Perchloroethylene 

(200) 

3.600 

IV.200 

9J.6 

74 

223.000 

62.700 

124.000 

98 

285.000 

303.000 

358.000 

95 

251.000 

150.000 

201.000 

90 

500.000 

120.000 

221.400 

98 

432.000 

1.047.000 

1.123.000 

95 

586.one 

508.000 

606.000 

1 gpa • 3.785 liter/ainute 9

 1 scfa • 1.699 N*3/hr 
P.27 

SUMMARY ANO CONCLUSIONS 

Catalytic oxidation is an air pollution control technique whereby 

VOCs and gas-phase organic air toxics are oxidized at destruction 

efficiencies of greater than 95%. The presence of the catalyst accelerates the rate of oxidation at a given temperature. This allows combustion 

at lower temperatures than are possible In thermal Incinerators. Catalysts can be either noble or non-noble metals deposited on either pelleted 

or monolithic supports composed of either ceramic or metal. Fixed and 

fluidized bed catalyst systems are available. The most Important factors 

affecting performance are operating temperature, space velocity (reciprocal of residence time), contaminant concentration and composition, catalyst properties, and the presence of catalyst poisons or Inhibitors 1n the 

emissions stream. The economics of catalytic oxidatior can generally be 

enhanced by the use of primary heat recovery to supplement and sometimes 

replace electric or gas preheating of the emissions stream before it is 

fed to the catalyst bed. Secondary heat recovery for ether process uses 

can also improve system economics. 

Catalytic technology has had 'timited application to tne control of 

groundwater stripping emissions in the field. The know, barriers to its 

application are the dilute nature of air emissions fron strippers, the 

high humidity content of the air stream, the complex chemical nature of 

the emissions, the need to control chlorinated compounds, m d the presence 

of catalyst poisons and inhibitors such as hydroo'n sulfide, biological 

organic matter, and mineral salts. Limited data from tne three known 

installations are available. 

The printing and graphic arts Industries make great _.e of catalytic 

oxidation for control of their air emissions. Two applications of catalytic technology are discussed. In both cases, the vendor claims high 

destruction efficiency (greater than 95%) at moderate Inlet temperatures 

[700 °F (370 °C)] due to the ease of combustinn the emissions. Both 

vendors identify the presence of phosphorus, silicon, sulfur, and halogens 

in the exhaust stream as potential Inhibitors of catalyst effectiveness. 

The supplier of the granular fixed bed hoble metal on alumina catalyst 

system is concerned primarily about masking from phosphorus and r.lllcon, 

and about deactivation from the halogens. The supplier of the

 #luid1zed 

bed non-noble metal oxide catalyst recognizes the potential for masking, 

but 1s not concerned since the surface of their catalyst pellet is believed to be continually cleaned In the fluidized bed. In addition, they 

are apparently not concerned about the deactivation of non-noble metal 

catalysts by halogens. Several causes of low destruction efficiency 

other than catalyst deactivation are Identified: low operating temperatures and catalyst levels, and the bypassing of the catalytic unit via 

cracked heat exchangers and leaking bypass dampers. 

22 
.*$•'*•'• »-'".'«W»r. -»5^,--..>. „ — P ?fl 

One vendor has provided Information about the use of a fluidized 

bed metal oxide catalyst system for destruction of chlorinated hydrocarbon emissions at five sites. They claim a very high destruction 

efficiency (greater than 99%) at moderate temperatures [700 °F (370 

°C)]. Of particular interest In this application 1s the high variability 

of organic emission rates and the need to add dilution air to the emission 

stream to avoid overheating of the catalyst bed. The need for scrubbing of 

hydrochloric ad d (HCl)from the catalytic incinerator exhaust is also of 

note. 

Nine catalyst systwn* fnr contaminant removal have been Identified. 

Most of these units are now used for controlling emissions from solvent 

stripping operations, paint spray booths, and similar industrial operations where the concentration of reactants range from 250 to 1,500 

ppmv or higher as limited by 25% of the lower explosive limit (LEL). 

Both nobie metal catalyts and non-noble metal oxide catalysts are 

represented. These use both pelleted ceramic and monolithic (honeycomb) 

ceramic or metal supports. Pelleted catalysts are 1n use 1n both fixed 

and fluidized beds. 

Finally, the economics of three control technologies are evaluated 

for groundwater stripping gaseous emissions. Existing data for carbon 

adsorption applications are compared to. estimates for the combustion 

technologies. Carbon adsorption has a more favorable annualized cost; 

however, the expected control efficiencies for thermal and catalytic 

incineration (higher than 95%) were much greater than the observed 

efficiencies for adsorption (70 to 90%). Cost analyses for an existing 

high efficiency carbon adsorption system are not presently available. 

23 

\ 
/ 

REFERENCES 

1 U.S. EPA. "Handbook: Control Technologies for Hazardous A1r Pollutants." EPA-625/6-86/014. September 1986. 

2 Telefax from Dowd, E. J. , ARI Technologies, Palatine, Illinois, to 

Kosusko, M., U.S. EPA. February 22, 1988. 

3 U.S. EPA. "Parametric Evaluation of VOC/HAP Destruction Via Catalytic 

Incineration." EPA-600/2-85-041 (NTIS PB85-19U87). April 1985. 

4 U.S. EPA. "Control of Volatile Organic Emissions from Existing Stationary Sources — Volume 1: Control Methods for Surface Coating Operations." EPA-450/2-76-028 (NTIS PB260386). November 1976. 

5 U.S. EPA. "Guideline Series. Control of Volatile Organic Compound 

Emissions From Manufacture of H1gh-Dens1ty Polyethylene, Polypropylene, 

and Polystyrene Resins." EPA-450/3-83-008 (NTIS PB84-134600). 

November 1983. 

6 U.S. EPA. "Organic Chemical Manufacturing. Volume 4: Combustion 

Control Devices." EPA-450/3-80-026 (NTIS PB81-220535). December 1980. 

7 Vosusko, M., M.E. Mullins, K. Ramanathan, and T.N. Rogers, "Catalytic 

oxidation of groundwater stripping emissions," Environmental Progress, 

to be published. 

8 Stallings, R.L., T.N. Rogers, and M.E. Mullins, "Air stripping of 

volafl e organic compounds from ground water," Journal of Environmental 

Sciences 28 (3), 1985. 

9 Gangwal , S.K., M.E. Mullins, J.J. Spivey, and P.R. Caffrey, "Kinetics 

and selectivity of deep catalytic oxidation," Applied Catalysis 36, 

1988. 

10 Tichenor, B.A., and M.A. Palazzolo, "Destruction of VOC via catalytic 

incineration," Environmental Progress 6 (3), 1987. 

11 U.S. EPA. "Air Stripping of Contaminated Water Sources - A1r Emissions 

and Controls." EPA-450/3-87-017 (NTIS PB88-106166). August 19tf7. 

y 12 Telecommunication. Ashworth, R.A., U.S. A1r Force Engineering & 

Services Center, with Kosusko, M., U.S. EPA. March 1, 1988. 

13 Telecommunication. Miller, P., Groundwater Technology, with Vancll, 

M.A., Radian Corporation. April 21, 1987. 

14 TEC Systems Division of W.R. Grace 4 Co. "A1r Pollution Control in 

the Heatset Web Offset Printing Industry." Report 8403. Undated. 

24 

/ 
15 Letter from Carman, R.A., TEC Systems, De Pere, Wisconsin, to Kosusko, 

M., U.S. EPA. February 18, 1988. 

16 Hardison, L.C , and E.J. Oowd, "Emission ccntrol via fluidized 

bed oxidation," Chemical Engineering Progress 73, 1977. 

17 Telecommunication. Bump, 0., CE Air Preheater, with Kosusko, 

M., U.S. EPA. February 23, 1988. 

18 Kenson, R., "Control of volatile organic emissions." Met-Pro 

Bulletin #1015, series 1000. 1981. 

25 

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