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RCRA Box 1883 

Prepped by Ollie Stewart 

Document Number: 

94) ll-B-256 

Docket Number: 

A-90-19 

Printed 12/3/200810:42:16 AM Sheet 94 of 171 
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RADIAN 

CORPORATIO N 

MEMORANDUM 

DATE: November 18, 1991 

TO: Les Evans, EPA/CPB 

FROM: Bart Ferrero, Radian 

A-90-19 

II B 256 

JtllJ 

EPAAIRDorKr 

SUBJECT: HON Control Technology for HON Process Vents 

The purpose of this memorandum is to document the control 

technology used for the control of process vent emissions. The 

emissions from process vent streams were controlled by either a 

flare, incinerator, or incinerator and scrubber, based on cost 

effectiveness of the control and halogen content of the stream. 

For the purposes of control and regulatory test method 

requirements, it was assumed that HAP reduction/control 

efficiency corresponded to documented VOC reduction/control 

efficiency. Thermal incinerator performance documentation 

provided by EPA is presented in Attachment A. 

Process vent streams were considered to be either 

haiogenated or nonhalogenated based on the stream components. A 

haiogenated stream was defined as a vent stream from a process in 

which any constituent, such as feed, intermediate, or product, 

contains one or more halogen atoms. Likewise, a nonhalogenated 

stream was defined as a stream from a process that contains no 

halogen atoms in any of its feeds, intermediates, or products. 

For nonhalogenated streams, a choice was made between one of 

four incinerators and a flare, based on cost effectiveness. The 

most cost-effective incinerator was chosen from among the options 

of 0 percent, 35 percent, 50 percent, and 70 percent heat 

recovery. The cost effectiveness of this incinerator system was 

then compared to that of a flare system to identify the optimal 

control system for the nonhalogenated stream. Design and costing 

of devices followed the procedures described in the Office of Air 

Quality Planning and Standard Control Cost Manual. 

confchmemo.r.tiw01 

Progress Center/3200 E. Chapel Hill Rd./Nelson Hwy./P.O. Box 13000/Research Triangle Park, N.C. 27709/(919)541-9100 
P.3 

In the case of a haiogenated stream, the only option 

considered was an incinerator with 0 percent heat recovery and an 

acid gas scrubber (packed bed absorber) to treat the incinerator 

waste gas. The waste gas must be treated because incineration 

of haiogenated molecules results in hydrogen halides (HCl, HBr, 

etc.) in the waste gas. Both the incinerator and scrubber were 

designed and costed as described in the Office of Air Quality 

Planning and Standards Control Cost Manual. No heat recovery 

was allowed in this case due to the possibility of corrosion in 

the heat exchanger. A flare was not considered due to design 

problems in capturing the exhaust stream from the flare. 

The calculation of total annual cost was based on the 

following assumptions: 

• The process operates year round continuously or 8760 

hours per year; 

• 100 ft. of duct from incinerator to scrubber; and 

• Electricity costs may not be less than $l/year. This 

assumption was made since the incremental change in 

controlling a vent stream to 98 percent from a control 

at less than 98 percent might result in an electricity 

cost less than one and appear to be equal to zero. The 

assumption was made to indicate some level of cost 

increase associated with the incremental change. 

cc: Project File 6.1 (M. Haley) 

contechmemo.htmOl 
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REFERENCES 

1. U. S. Environmental Protection Agency. Office of Air 

Quality Planning and Standards Control Cost Manual (Fourth 

Edition). EPA 450/3-90-006. January 1990. 

2. Memorandum. Pandullo, Richard F., Radian Corporation, to 

Wiley Barbour, Radian Corporation, Les Evans, EPA/CPB, 

et al. "Summary of April Meeting to Discuss Thermal 

Incinerator Cost Issues." April 27, 1990. 

contechmemo.htm01 
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ATTACHMENT A 

DOCUMENTATION OF THERMAL INCINERATOR PERFORMANCE 

contechmemo.htmO1 
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ISSS/ 

V 

«c «»0' ^

v 

TJNITEO STATES ENVIRONMENTAL PROTECTION AGENCY 

Office of Air Quality Planning and Standards 

Research Triangle Park. North Carolina 27711 

ccr i • rj; 

MgMORAWDUM 

SUBJECT: Thermal Incinerator Performance for NSPS 

HA lie cofi"^ r : 

froosrll 

fler.*e-H" Kin* 

"To** Oli^A 

6«r*f Ftrczro 

FROM: Leslie Evans (MD-13) 

TO: All CPB Engineers 

John Crenshaw, Radian 

Roy Neulicht, MRI 

Bob Zirbonia, RTI 

Susan Wyatt asked me to remind all branch engineers that our 

reference for thermal incinerator removal efficiency is still the 

memo: 

Memo and attachments from Farmer, J.R., EPA, to 

distribution. August 22, 1980. 29 p. Thermal Incinerator 

and Flares. 

Attached you will find an example of language used in the 

BID to justify the 98 percent reduction (From the Reactor 

Processes Draft EIS) and a copy of the memo itself (for the 

docket). 
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y***~ 

corrosion «Wt o contact with add gases formed during tht combustion of 

these strtetmV 

*.2.2.2 Thermal Incinerator Removal Efficiency. Tht VOC dtstructlon 

efficiency of a thermal oxidizer can ot affected by variations 1n chamber 

teaperature, residence time. Inlet VOC concentration, compound type, and 

flow regime (mixing). Test results show that thermal oxidizers can achltvt 

98 percant dtstructlon tffldency for most VOC compounds at combustion 

charter temperatures ranging from 700 to 1,300*C (1,300 to 2.370'F) and 

residence tints of O.S to 1.5 seconds.1*

2

 These data indicate that significant variations 1n destruction tffldtncy occurred for Ct to C8 alkanes and 

olefins, aromatics (benzene,.toluene, and xylene), oxygenated compounds 

(methyl ethyl ketone and Isopropanol), chlorinated organics (vinyl 

chloride), and nitrogen-containing species (acrylonitrile and ethylamlnes) 

at chamber temperatures below 760*C (1,400*F). This Information, ustd 1n 

conjunction with kinetics calculations. Indicates tht combustion chatter 

parameters for achieving at least a 98 percent VOC destruction tffldtncy 

art a combustion tamperature of 870*C (1,600*F) and a residence tine of 

0.75 seconds (based upon residence In tht chamber volume at combustion 

temperature). A thermal oxidizer designed to product these conditions 1n 

tht combustion chamber should be capable of high dtstructlon efficiency for 

almost any nonhalogenated VOC. 

At temperatures over 760*C (1,400*F), tht oxidation reaction rates art 

much fasttr than tht rate of gas diffusion mixing. Tht dtstructlon efficiency of the VOC then becomes dtptndtnt upon the fluid Mechanics within the 

oxidation chamber. Tht flew rtglmt must assure rapid, thorough mixing of 

tht VOC stream, combustion air, and hot combustion products from the burner. 

This tnables tht VOC to attain tht combustion tamperature 1n the presence of 

enough oxygen for a sufficient time period for tht oxidation reaction to 

reach completion. 

Based upon studies of thermal oxldlztr efficiency, 1t has been 

concludtd that 98-percent VOC dtstructlon or a 20 ppmv compound axlt 

concentration 1s achievable by all new Incinerators considering current 

ttchnology."* Because of much slower combustion reaction ratts at lower 

Inlet VOC concentrations, tht maximum achievable VOC destruction effldtncy 

decreases as Inlet concentration dtcrtasts. Therefore, a VOC weight 

percentage reduction eased on the mass rate of VOC txltlng the control 

device versus tht mass rata of VOC entering tht dtvlct, would bt approprlatt 

for vtnt streams with VOC concentrations above approximately 2,000 ppmv 

(corresponding to 1,000 ppmv VOC 1n tht incinerator Inlet stream slnct air 

dilution 1s typically 1:1). For vtnt streams with VOC concentration btlow 

approximately 2,000 ppmv, 1t has bttn determined that an Incinerator outlet 

concentration of 20 ppmv (by compound), or lower, 1s achltvablt by all new 

thermal oxidizers.ki Tht 98 percant efficiency estimate Is predicated upon 

thermal Incinerators operated at 870*C (1,600*F) with 0.75 seconds residence 

time. Study results show that these conditions yield conservative estimates 

of costs and energy use for these type units. 

4-22 
e»« 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

_ Office of Air Quality Planning and Standards 

- Rtstarch Trianglt Park, North Carolina 27711 

OATI: AU& 

suajacT:. Thermal Incinerators and Flares 

FftOM: jack 

Chemi 

n i

 See Below 

R. Farmer, Chief ; 

icals and PetroleunTJr^hch (MO-13) 

A__J.9.-32 

II-B-31 

The attached materials provide guidance on tht performance of 

thermal incinerators, and should be considered when these control 

devices are evaluated for a NSPS or NESHAP. 

Cave Mascone's two memoranda on thermal Incinerator performance 

present a good summary of all the information we currently havt on 

thermal incinerators. Most questions that may nttd answering for a 

NSPS or NESHAP should be addressed 1n thest two memoranda. These two 

memoranda should be added to the docket of any standard where thermal 

incinerators are included as a control device in a regulatory 

alternative. 

A report is being prepared by EEA which is an assessmtnt of a German 

study on flareST The EEA report will also be distributed as soon as 

it becomes available. 

Attachments 

Addressees: 

C?B Section Chiefs and Lead Engineers 

SDB Section Chiefs and Lead Engineers 

Bob Ajax 

Jim Bain 

Don Goodwin 

Fred Porter 

Gtorgt Walsh 

New Source Standards Contractors 

Tom Bibb 

£ •* P«M> 1)304 <*•«.».?«» 
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«f~ 

UNITEO STATES ENVIRONMENTAL PROTECTION AGENCY 

" " # 

suajtcT: Thermal Incinerator Performance for NSPS 

MOM : David C. MasconeJC?) 

Chemical Manufacturing Section, CPB 

TO: Jack R. Farmer, Chief 

Chemicals and Petroleum Branch 

Over the past few months, CMS has investigated incinerator efficiency, 

cost and fuel use. The purpose of this study has been to pick an 

efficiency that represents the highest control level acMevablt by all 

new incinerators, considering available technology, cost and energy use. 

Conclusions 

Based on our study, we conclude that 98 percent VOC reduction,?or 

20 ppmv by compound exit concentration, whichever 1s less stringent, 1s 

the highest control level achievable by all new Incinerators, considering 

available technology, cost and energy use. This level. 1s expressed in 

both percent reduction and ppmv to account for the leveling off of exit 

concentrations as inlet concentrations drop. This level 1s based on 

incinerator operation at a maximum of 1600*F and .75 second residence 

time. The costs and energy use of achieving this level art based on 

recuperative heat recovery capable of lowering the flue gas temperature 

to 510"F. 

From our study, wt also conclude that mixing 1s a critical factor 

in efficiency, a factor of equal or greater importance than other factors 

such as temperature. After surveying available means of improving 

mixing, we conclude that Incinerator adjustment after start-up 1s the 

most feasible and efficient. Tht control levels 1n tht previous paragraph 

are based on such an adjustment. 

From our study, wt also conclude that, with proper use of recuperative 

heat recovery (RHR), no significant energy penalties occur with changes 

1n combustion temperature. The reason 1s that, based on the technical 

limits of heat recovery and present fuel costs, tht optimum Incinerator 

exit gas temperature is slightly above 500*F, regardless of combustion 

temperature. Since incinerator fuel ust dtptnds on exit gas and not 

combustion temperature, RHR can essentially eliminate the fuel penalty 

of increasing combustion temperature. 

• a. • _ U.0-4 (»•». ].?<) 
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-:.^t" • 

01scuss1ow 

— ' •**& 

T M s saanpk discusses our data and findings on Incinerator efficiency, 

cost and fueaSe * and presents the logic behind the choice of the above 

control 1evtfl?r£Th1s section has three parts, one on efficiency, one on 

cost and fuel use, and one on control levels. Tables cited 1n this 

section are at the end of the memo. 

In using tht conclusions and data from this discussion, the reader 

should be aware of several qualifications. First, this discussion picks 

a control level applicable to all new incinerators, evtn tht worst 

casts. In reality, thtrt will be a distribution of casts from worst to 

best. Thus, 1n many situations, incinerators will achieve greater than 

98 ptrctnt, or less than 20 ppmv, control at less than 1600*F and 

.75 seconds residence time. 

Second, this discussion lists specific incinerator conditions 

(temperature, residence time, heat recovery) for analysis purposes only, 

i.e. to calculate cost, fuel and emission impacts. This memo does not 

recommend that these conditions be specified in regulations. As just 

noted, this set of conditions represents only onfof many with which 

to achieve 98 ptrctnt reduction or 20 ppmv. Thus, the control Itvtis in . 

tht abovt conclusions, not tht incinerator conditions, should bt tht 

basis for regulations. 

Third, this discussion focusts on thermal incineration since this 

control method has tht widest applicability to control of ducttd VOC 

emissions. This memo dots not conclude that Incineration 1s applicable 

to all situations or that, whtn applicable, incineration 1s tht only 

feasible control method. 

Fourth, this discussion covers incinerators operating with relatively 

constant inlets and flows and with waste gas flows greater than S00 scfm. 

This in general includes incinerators on solvent drying operations, 

polymer production plants, and air oxidation units. For Incinerators 

with varying inlet conditions or small flows, such as those on organic 

liquid storage tanks, tht futl and capital cost calculations in this 

memo may not hold. Since these calculations are a critical basis for 

the above conclusions on efficiency, thtst tffldtncy conclusions art 

not appllcablt to such Inclntrators. 

Finally, this discussion covers new Incinerators applied for control 

of VOC for oxidant reduction purposts. Existing inclntrators may not bt 

physically capable of achieving tht temperature, residence time and heat 

recovery conditions listed 1n this memo. Thus, these incinerators may 

not-be able to reach 98 percent or 20 ppmv. On the other hand, incinerators 

for control of toxic or hazardous VOC nttd not be limited to 98 ptrcent 

or 20 ppmv. As discussed below, higher efficiency incinerators are 

possible for all compounds with some development and design cost. 
N^ -3-

Efficiency - Tht available diti on Incinerator efficiency 1s dtscrlbtd 

in Table l-and summarized 1n Tablts 2-4. The data Include results frost 

lab scaleiftlnerator tests conducted by Union Carbide and from field 

tests run-MtfPA, Lot Angeles County and chemical companies. 

These^dita were analyzed to detennine the impact of incinerator 

variables on efficiency. Six variables were studied, namely temperature, 

residence time, mixing, inlet concentration, flow regime, and type of 

compound, in three analyses. These analyses are described below. 

Mixing and flow regime are defined in Appendix A. 

The first analysis was designed to remove the influence of mixing. 

This was desired since mixing cannot be measured and thus its impact on 

efficiency cannot be readily separated when studying the effect of other 

variables. The Union Carbide lab work was chosen for this analysis 

since its small size and careful design best assured consistent and 

proper mixing. 

The results of the Union Caribde work are shown in Table 2. These 

results show moderate increases 1n efficiency with temperature, residence 

time and type of compound. These results also show the impact of flow 

regime on efficiency. This subject is discussed further 1n Appendix A 

on mixing and flow regime. Finally, the results show that a given } 

temperature does not correspond to a given efficiency. Rather, Increasing 

temperature increases efficiency by narrowing the range over which 

efficiencies fall and Increasing the average of the range. 

The next analysis focused on mixing. To accomplish this*, cases 

were picked where all variables except mixing were held constant or 

accounted for in other ways. It was then assumed any changes in efficiency 

would be due to changes in mixing. 

The case most directly showing the effect of mixing on efficiency 

is presented 1n Table 3. The Petro-tex data show the efficiency changes 

due to two modifications of the Incinerator after start-up. These 

modifications increased efficiency from 70 percent to over 99 percent, 

with no change in temperature. The modifications include repositioning 

baffles and burners, and rerouting Inlet combustion air. 

A case indirectly showing the effect of mixing 1s presented in 

Table 5. These data compart tht efficiency of the Rohm and Haas (R&H) 

incinerator in combusting four specific compounds with that of the Union 

Carbide lab unit. Tht lab unit clearly outperforms tht R&H unit. The 

data from both units are based on tht same temperature, residence time 

and inlet stream conditions. The more complete mixing of the lab unit 

is judged the cause of the differing efficiencies. 

Another case Indirectly showing the effect of mixing 1s presented 

in Table 6. These data are a partial 1.1st of L.A. County tests where 

efficiency dropped or remained the same with Increasing temperature. In 

total this result occurred in 21 of the 50 L.A. County tests 1n which 
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v f/r 

the same Incinerator was tested at different temperatures. As above, 

all factorv|»cept mixing remained the same or can be accounted for in 

other weyslftJnus,. changes in the completeness of mixing are judged to 

be the caiwd f the results. 

The final analysis was designed to study the effect of all variables 

it once. The L.A. data were chosen for this analysis since the L.A. 

units operated over a wide range of each of the variables of Interest. 

In addition, the L.A. results represented the largest body of available 

efficiency data and thus were the most amenable to statistical analysis. 

The results of the analysis of the L.A. data are shown in Table 4. 

These results show a weak relation between efficiency and inlet concentration 

and no relation between efficiency and temperature. 

The temperature vs. efficiency results are surprising. Kinetic 

theory and the lab scale results show large increases in efficiency over 

the 300*F range in Table 4, but in fact no such increase occurred in the 

L.A. data. Detailed analysis of this data points to poor mixing as the 

cause of these results. This analysis 1s described 1n Appendix A to 

this memo. 

The conclusion from these three analysis 1s that mixing 1s the most 

important variable 1n incinerator efficiency. This 1s based on tht 

large changes in efficiency in the R&H and Petro-tex results and tht 

ability of mixing to mask tht Impact of temperature in tht L.A. data. 

This 1s not to conclude that temperature, residence time and other 

variables have no Influence on efficiency. These variables do have an 

important, though smaller, influence. 

Cost and Fuel Use - The data used to study Incinerator cost and 

energy use are contained in the Hydrosdence report on thermal incineration. 

Selected parts of these data are shown in Table 7 and 8. These data 

were used to analyze the relations between capital cost, energy use and 

heat recovery. In addition, the costs of efforts to improve mixing were 

also analyzed. These analyzes are discussed below. 

The first analysis studied the cost trade-offs between heat recovery 

and energy use. The results of this analysis are shown in Table 7. 

This table lists tht Incremental capital costs and energy savings with 

increasing recuperative heat recovery (RHR). The 70 percent RHR case, 

which corresponds to a flue gas temperature slightly above 500*F, represents 

the maximum feasible level of recovery. Beyond 70 percent RHR, problems 

arise with precombustlon in the heat exchanger and with condensation of 

water in the flue gas and possible corrosion. 

The results on Table 7 indicate that the maximum feasible RHR 

should be used. Up to this maximum, except for the 1000 scfm case, the 

capital cost of each Increment of RHR is more than offset by the incremental 

energy savings. The basis for these savings is the increasing cost of 
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fin 

.5-

* 

energy. In. older designs, based on cheeper fuel, cost savings from heat 

recovery were not large enough to justify maximum RHR. However, with 

escalating/fuel costs, extra capital equipment has become cheaper than 

energy. 

The results on table also indicate that, with the proper use of 

heat recovery, negligible energy penalties occur with increasing combustion 

temperature. The reason is that the energy use of an incinerator depends 

on exit gas temperature, not combustion temperature. And as noted 

above, the optimum exit gas temperature is slightly above 500'F, regardless 

of combustion temperature. Higher exit gas temperatures are not warranted 

since additional heat recovery produces a net savings. Lower exit gas 

temperatures are prevented by technical limits. Thus, with optimum RHR, 

increasing combustion temperatures will lead to negligible Increases in 

energy use. 

The second analysis concemed the capital cost differences between 

incinerators designed at 1400*F and 1600#F. The results of this analysis 

are shown in Table 8. These results show moderate Increases in capital 

costs and small to moderate increases 1n annualized costs between the 

1400*F and 1600*F incinerators. The major factors in the Increase are 

the larger recuperative heat exchanger and larger combustion chamber 

needed for the 1600*F degree unit. 

The final analysis concerned the cost and feasibility of various 

methods to improve mixing. Four methods were studied: pilot plants, 

lab work, engineering design and adjustment after start-up; 

Pilot plant work 1s judged too expensive. The costs involved in 

constructing and operating the pilot plant unit, providing a waste gas 

stream, and collecting and analyzing the data could well exceed the 

capital cost of the full scale unit. A quarter to a half million dollars 

could be required for such work for small incinerators, and up to a 

million dollars for larger units. Pilot plant work appears more appropriate 

as an EPA or vendor research project. 

Two of the alternatives, lab work and engineering design, appear 

affordable but are not feasible. Lab work provides good data on kinetics, 

but no useable data on mixing. Engineering equations are useful in many 

situations, but few such equations exist for mixing. The number of 

trays 1n a distillation column can be reasonably calculated; the number 

of baffles in an incinerator cannot be. 

The final alternative, adjusting the Incinerator after start-up, 

does appear both affordable and feasible. Such an adjustment would 

involve repositioning baffles, adjusting ducts and performing similar 

tasks while measuring efficiency, temperature and similar variables. 

Such a procedure applies to Incinerators the same adjustment that process 

equipment receives after start-up and would Involve the same, moderate 

time, expertise, and costs. Finally, the success of such a procedure 

has been demonstrated by Petro-tex. 
control Level - Based on the above findings, a series of conclusion* 

wer: made "Mch lead to the choice of 98 percent reduction, or 20 ppew, 

(98/201 asr^avhighest control level achievable for all new incinerators, 

conslderin«TM!j.ilable technology, cost and energy use. These conclusions 

are discusX^elow. 

. First, Incinerator combustion temperature has little Impact on cost 

and energy effectiveness ratios. This conclusion Is based on the small 

changes with temperature that occur in the three items, namely annualized 

cost, energy use and VOC control efficiency, that make up these ratios. 

As discussed above, these three items all increase less than 15 percent 

with temperature over a 1300°F to 1600*F range. Simple math shows that 

such small changes 1n the numerators and denominators of the cost and 

energy effectiveness ratios lead to almost negligible changes in tht 

ratios. Calculations with the actual numbers confirm this. Based on 

a 5 percent increase in VOC control, a 12 percent increase in annualized 

costs and essentially no change in energy use (see Table 2 and 8 and 

previous discussion), a 1400*F to 1600'F change in temperature increases 

cost per pound VOC controlled only 5 to 10 percent and actually decreases 

energy uses per pound VOC controlled. 

Second, the highest control limit should be based on Incinerator 

operation at 1600°F. .This conclusion is based directly on the first, | 

I.e. that over the range of interest temperature does not adversely 

affect cost or energy effectiveness. Given this, higher temperatures, . 

with higher control efficiencies, are preferred. 

This conclusion on operating temperature 1s also based on the 

practical limits on metal recuperative heat exchangers. Based on the 

logic in the preceding paragraph, there 1s no upper limit to the combustion 

temperature which should be used. However, above 160Q*F, ceramic recuperative 

heat exchangers are required. Since these exchangers are more complex 

and costly, and less typical, than metal designs, the decision was made 

not to rely on them in considering the achievable control levels. Thus, 

1600*F was chosen for the incinerator operating temperature. This 

conclusion was further supported by the high control levels found 

achievable at this temperature, as discussed below. 

Third, and finally, 98 percent VOC reduction, or 20 ppmv by compound, 

whichever 1s less stringent, represents the highest achievable control 

level for all new Incinerators, considering available technology, cost 

and energy use. This 1s based on incinerator operation at 1600'F, as 

discussed 1n the preceding paragraph, and on adjustment of the Incinerator 

after start-up, as discussed in the section on cost. The dual statement 

of the conclusion. I.e. i% percent reduction or ppmv, accounts for tht 

observed fall-off of efficiency at lower Inlet concentrations. The 

98/20 numbers themselves were picked by analyzing three different control 

levels, 99 percent or 10 ppmv, 98 percent or 20 ppmv, and 95 percent or 

30 ppmv. 
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m 7

~ . ••: ; * 

The 99/10 level is judged too stringent. Two of the six non-L.A. 

tests and 55 percent of the L.A. tests fall this criteria. Consideration 

was g1vej£& the fact that many of the units tested were below 1600 and 

d i d notfK * 900d mixing. However, due to the large percent that failed, 

it is 44P f that even with higher temperatures and moderate adjustment, 

a large mawe r of units would still not meet the 99/10 level. 

The 98/20 ppm level is judged attainable. All of the non-L.A. and 

the majority of the L.A. units meet this criteria. There is concern 

over the large numoer cf L.A. tests that failed, i.e. 43 percent. 

However, two factors outweigh this concern. 

First, all the non-L.A. units meet the criteria. This is significant 

since, though the L.A. units represent many tests, they represent the 

same basic design. They all are small units designed over a decade ago 

to meet a rule for 90 percent reduction. They are for similar applications 

for the same geographic region designed in many cases by the same vendor. 

Thus, though many failed, they likely did so due to common factors and 

do not represent a wide spread inability to meet 98 percent reduction or 

20 ppmv.. 

Second, the difference between 65 percent failing 99/10 and 43 percent 

failing 98/20 is larger than a direct comparison of the percentages 

would reveal. At 98/20, not only did fewer units fall, but those that 

did miss the criteria did so by a smaller margin and would require less 

adjustment. Dropping the criteria from 99/10 to 98/20 drops the failure 

rate by 20 percent, but 1s judged to drop the overall time and cost for 

adjustment by over 50 percent. 

The difference between the two levels is even greater when the 

adjustment effort for the worst case is considered. The crucial point 

is how close a 99/10 level pushes actual field unit efficiencies to 

those of the lab unit. Lab unit results for complete backmlxing range 

throughout the 99 range at 1600#F, meaning a 99/10 level would force 

field units to almost match lab unit mixing. Appendix A describes the 

reasons the complete backmix results were used. Backing off to 98/20 

increases the margin, especially for the worst cases. Given that exponential 

increases may occur in costs to improve mixing as field units approach 

lab unit efficiencies, a drop from 99/10 to 98/20 may decrease costs to 

improve mixing in the worst cases by an order of magnitude. 

The 95/30 level was judged too lenient. The only data indicating 

such a low efficiency was from L.A. All other data showed 98/20. The 

non-L.A. data and lab data meet 98/20 and the Petro-tex experience 

showed that moderate adjustment can increase efficiency above 98. In 

addition, in the previous discussion on efficiency, the L.A. units were 

judged to have poor mixing. The mixing deficiencies were large enough to 

mask the effect of increasing temperature. Thus, it 1s judged that 

98/20 could be reached with moderate adjustment and that a 95/30 level 

would represent a criteria not based on the best available units, considering 

cost, energy, and environmental impact. 
P.16 

Table 1 

"T * Description - AveUable 

Incinerator Test Date 

Below arapBscrlbed the available incinerator test data. Four sets of 

such data are'jtrtsent. These sets are lab scale incinerator data from tests 

by Union CarbidVend field unit data from tests conducted by EPA, chemical 

companies and L.A. County. 

Union Carbide Test Data - These data show the combustion efficiencies achieved 

on 15 organic compounds in a lab scale incinerator operating between SCO and 1533°F 

and .1 to 2 second residence time. The incinerator consisted of a 130 centimeter 

thin bore tube in a bench size tube furnace. Outlet analyzes were done by direct 

routing of the incinerator outlet to a FID and GC. All Inlet gases were set at 

1000 ppmv. 

2.3,4 

EPA Test Data - These data show the combustion efficiencies for full scale 

incinerators on air oxidation vents at three chemical plants. These three plants 

are the Uniton Caribde, Taft, Louisiana, and Rohm & Haas, Oeer Park,. Texas, 

acrylic acid units and the Denka, Houston, Texas unit. The data for 

Union Carbide include test results based on two different incinerator temperatures 

and the data from Rohm & Haas, results from three temperatures. In all tests 

integrated ii:s were used for sar.pling and a GC/FIO was used for organic 

analysis. 

5,6.7.8 

Chemical Company Test Data - These data are from tests performed by 

chemical companies on incinerators at three air oxidation units. The companies 

and units are, Monsanto at their acrylonitrile unit at Alvin, Texas, 

Petro-tex at their oxidative butadiene unit at Houston, Texas, and Koppers at 

their maleic anhydride unit at Sridgeville, Pennsylvania. The Monsanto 

incinerator burns both liauid and caseous wastes from the acrylonitrile unit 

enu Lhe suppers incinerator is actually a boiler adapted to burn gaseuus wai-.es. 

In all tests, analysis was performed by GC/FID. The sampling was performed 

as follows: 

Monsanto - Cold water scrubbing - AN, Act-!, HCN; metal sample bombs -

remaining compounds 

Petro-tex- Integrated bag - inlet; glass syringe - outlet 

Koppers - Glass sample bombs and charcoal tubes 

g 

L.A. County Test Data - These data are from over 200 tests by L.A. County 

on various waste gas Incinerators, most of which are on coating operations. Data 

from 147 tests were used, with the regaining tests being discarded since back-up 

data were missing, the incinerators were catalytic units or similar reasons. In 

the L.A. data, only flow, temperature, and inlet and outlet VOC concentration 

are reported; data on compounds and; residence time are not present. . 

Evacuated 40 liter gas cylinders were used for sampling and oxidation to C02 

and NDIR were used for analysis. 
P.17 

Table 2 

•- - Results - Union Cirblde Tests* 

Destruction Efficiency 

Under Stated Conditions 

Fl0... ^mperatur e . Residence Time/Compound • 

(F) .75 seconds -±12. Resine** 

thy! Viry! 

Acryiate Ethanol Ethylene Chloride Ethylene 

l v.r oo c 94.6 52.6 78.5 S7.2/57.5 

Two-Stage 1300 -..* 

3ackmixinS uo o 99.9 99.6 99.3 99.C 96.6/9... 

150 0 gc.g 99.9 99.9 99.9 99.9/93.S 

1SQ 0 09.9 99.9 99.9 99.9 99.9/95.= 

C a - olet e 1300 93.9 85.8 84.4 69.9 78.2/91.5 

SecS&ng 1400 99.7 95.3 95.6 93.1 93.7/97.S 

1 5~ 99.9 99.0 98.7 98.4 98.0/9S.C 

, 1 M o3.9.. 99.7 99.6 99.6 99.4/93.3 

, -3 09.9 99.9 99.5 90.2 .97.3/95.5 

piu

»

F l w u

- ° ••;,; ; 9 9 . 9 99.9 99.9 99.9/5:-.:-

r>« r* 

;.0°3 . S3.9 95.9 99.9 "99.9 99.9/59. 

, 0 0 99-5 »•» »•» "'9 .

S3'5/"-i 

*The results cf the Unt ion Carbide work are presented as a series of equations. T'.-s 

equations relate destruction efficiency to temperature, residence time and flo.; rar, 

for each of 15 compounds, "he efficiencies 1n this table were calculated from 

these equations. 

Three flow regi-ss are presented, two-stage backmixing, complete backmixing and 

r uo flow. Two stage backmixing is considered a reasonable approximation of actus" 

field units, with complete backmixing and plug flow representing the extremes, "r.z 

subject of flew regime is further discussed in Appendix A. 

pi 
P.18 

r/v 

Table 3 

Results - EPA and Company 

Incinerator Tests 

-Orrpcny 

Residen 

Time/In 

Flow (S 

Temperature 

(FO) 

Number of 

Test Runs 

Inlet 

VOC 

(ppmv) 

Outlet 

VOC 

(ppmv) 

% V0CT 

Control 

Ur. i cn 

Cirbide 

2 to 3 sec/ 

20,500 

1160 

1475 

6* 

3* 

11900 

11900 

243 

10 

95.1 

99.9 

Haas 

1 sec/ 

Tank Farm Vent, 

(TFVi-12,500. 

Oxidizer Vent, \ 

(OXVj-iO.OOO 

1425 

1510 

1343 

3* 

4* 

1* 

TFV 2580 

OXV 11600 

TFV 2600 

OXV 12800 

TFV 2410 

OXV 12200 

1.330 

150 

25 

82.5 

•S3.3 

99.7 

Denka 

•'.or.santo 

Koppers'' 

.6 sec;13,000 

(Unit s--:i) -

18' Oil. X 35' 

(Outlat ?"••:•*•) 

75,000 

.6 sec/30,000 

f..Kn«x " .6 sec/14,400 

1400 

Confidential 

950 13 93.5 

1800 

1400 

Unit 1-6** 

Unit 2-3** 

Inlet-4** 

Outlet-6* 

N/A Set 1 

Set 2 

Set 3 

Conf. 

Conf. 

850 

10300 

10650 

10300 

25 

47 

Set 1 7 

Set 2 11 

1000 

215 

10 

>99 

>99 

99.0 

97.2 

70.3 

94.1 

99.6 

'Si-ipiing conducted with integrated bags. 

•^SsMpUng conducted with grab sample bombs or syringes. 

'•VOC does not include nethane of ethane. This definition of VOC is different 

used in earlier mesas on EPA tests, and thus results reported here may differ 

in the earlier mesa. 

TVOC ','. destruction 1s by weight percent. 

'-TH* dita in Set 1 and 2 for Koppers were taken during different time periods. 

""Inlet and outlet VOC for Petro-tex reported as ppmv methane. The data in set 

taken prior to adjustment of the incinerator; the data in sets two and three, 

\ adjustment. The specific alterations made by Petro-tex are described in refe 

rre- that 

fro- resuV 

cne were 

after 

rences 3 ar 
P.19 

_w 

. * • •'" 

Table 4 

Results - L.A. Incinerator Tests 

Destruction Efficiency* 

Under Stated Conditions 

'ostruct'on Efficiency vs.-"em-arature 

1st Median 3rd 

. , rfl , , tlir , RaP -a Number Of ISt neuion jru 

,e^e ature Rar.s- . ^ Quartile** Quartile 

-,-> 93 ft 96.4 98.0 

1300 - 1380 -

2

 " , u 

_.- 94 0 96.0 98.6 1385 - 1420 *-

 94, ° * „ _ 

91 5 95.0 97.4 1425 - 1475 *s 91

-

5 

_ ?* 91.5 96.5 98.6 

1480 and greats* -- " s 

Destruction •--•c'iar.zy vs. Ir.'Tet Concentration 

0 - 399 

400 - 799 21 

7000 or more 1 r; 

•v-s«r ef 1st Median 3rd Inlet Concentra-::-

 n^Vt° Qua ;!i l e . . Quartile (VOC as ppmv car::r.; -eSwS wusrw.i* 

" 1 6 85.1 90.8 96.0 

91.0 93.3 97,2 

ii 90.0 ' 92.5 94.7 

SOD - 1199

 U

 ft, Q Q7 o 

1600-1999 5 53.0 4 9. 0 

n 91.0 95.5. 57.3 

?r,nn - 2"Oc ' ' 

, , 95 9 98.4 53.S 

" ° ° -

3

" » . 0 ". 8 99.0 

320 0

 " 393 9 , 9 . 98.4 99.2 

^°- 499 9 ' j 97.5 98.1 

501 0

 -

5

" ! 96.0 97.5 

63! 5

 -

6 9 " 8 3.2 98.7 

....•ruction efficiency ss weigh, oercant certon. ,,_,,, . 

due to the manner in whicn --r.e o-ta \.-re due 
P.20_ 

Table S 

Result Comparison -

Incinerator vs. Rohm & Haas Incinerator* 

Compound 

propane 

propylene 

ethane 

ethylene 

Rohm & Haas 

Incinerator 

Inlet 

(lbs/hr) 

900 

1800** 

10 

•. 30 

Outlet 

(lbs/hr) 

150 

150** 

375 

190 

Lab 

Incinerator 

Inlet Outlet 

(grans/sec) (grams/sec) 

'.740 855 

9.0 

18.0 

.1 

.3 

27.4 

.08 

.70 

.50 

.43 

1.71 

'I, VOC Oes true tier. 63.4% 93.8 

•Table shows tha testruttion efficiency on the four Usted compounds for the 

Rohr: I Haas (R£H) field and Union Carbide (UC) lab incinerators. The R&H results 

are measured; the LC resultVare calculated. Both sets of results are based on 

1425*F combustion temperature end 1 second residence tine. In addition, the 

UC results are base? on complete backmixing and a four step combustion sequence 

consisting of prccane to propylene to ethmc tc ethylene to CC2 «"--: rvv. Tl-.viu 

"• ._.- f..c itc..* arc v.orst case assumptions. 

**Are not actual values. Actual values are confidential. Calculations with actual var. 

cive similar results. 
P.21 

" > 

» c» 

Test No. 5?:*. 

1158 

1214 

1215 

1329 

1746 

1842 

2130 

2235 

2259 

2624A 

26248 

Table 6 

Results - Selected L.A. Incinerator Tests* 

Temperature 

(•F) 

1300 

1400 

1400 

151C 

1400 

1500 

1300 

1225 

1375 

l - » w 

1320 

141C 

15C3 

1140 

1235 

142b 

1300 

1375 

1495 

1400 

1450 

1430 

1450 

1200 

1450 

1200 

1420 

Inlet** 

Concentration 

2300 

1600 

1200 

1200 

1500 

1500 

3100 

3700 

3300 

2700 

7430 

6247 

7370 

1260 

irvj 

l-.J 

801 

777 

890 

11065 

•" 10731 

871 

871 

4110 

3090 

1405 

1164 

Outlet** 

Concentration 

60 

83 

23 

89 

94 

170 

27 

70 

120 

7 

83 

88 

104 

83 

60 

109 

34 

66 

63 

97 

254 

90 

131 

60 

65 

23 

13 

.Partial listing of tests where incinerator l«ape.4.u.i ^ -. 

% vo : 

Destruction 

57. £ 

S4.5 

53.2 

92.7 

52.5 

89.1 

99.2 

98.1 

95.9 

99.7 

93.9 

.98.5 

98.5 

93.5 

Si. 5 

S3.0 

53.9 

85.4 

92.7 

59.1 

' 57.5 

£5.1 

72.2 

52.1 

-'3-4 

S3. -

52. E 

reased v;.... ••-

carbon. 
f« Table 7 

«yr;v 

Cost Comparison - Incremental 

Capital Cost and Fuel Savings 

with heat Recovery* 

Incinerators not Requiring SupplementalAi r** 

Recuperative 

Hsat Recovery 

• (s) 

30 

50 

70 

30 

50 

70 

Incinerat 

?.;_.-..:•.-.*•.•. : 1 — 

Heat R-acovery 

(S) 

30 

50 

70 

Inlet Flow 

(SCFM) 

ors Reciirir.g 

ISCFM)" 

Incr. 

Capital 

SI 5,500 

$6,500 

$10,300 

Incr. 

Capital 

$22,500 

SI 2,000 

$18,000 

Supplemental Air 

Incr. 

Capital 

$13,000 

$5,000 

$2,000 

1000 

Incr. 

Fuel 

$11,500 

$7,500 

$7,500 

3C00 

Incr. 

Fuel 

$34,500 

$22,500 

$22,500 

700 

Incr. 

Fuel 

$27,000 

$10,000 

$9,000 

2000 

Incr. i,. c r. 

Capital Fuel 

$18,500 $23,COO 

$9,900 $15,000 

$13,500 $15,000 

10000 

Incr. Incr. 

Capital Fuel 

$36,000 $115,000; 

$29,000 $75,000 

$59,000 $75,000 

• «A« I 

* * V * 

Incr. Incr. 

Capital Fuel 

$27,000 $178,000 

$12,000 $84,000 

$13,000 $77,000 

* Ocllar figures are the incremental annualized capital costs and incremental 

annual fuel cost savings for increasing the heat recovery from the previous 

level to the listed level. For example, the figures on the 50* line are the 

costs and savings of going from 30S to SOS heat recovery, and on the 30!; line, 

cf going frors no heat recovery to 30S recovery. Costs are based on an 

incinerator operating at 1500°F and .75 seconds residence time. 70S recuperativ; 

heat recovery corresponds to an exit gas temperature of approximately £50^?. 

** Costs based on Reference 10. 
Hi 

incinerators ? 

Table 8 

Cost Comparison • Incremental 

Costs of Combustion 

Temperature Increase 

rina Sucolsrer.tal Air* 

Flow 

(scfn) 

700 

5000 

25000 

50000 

Capital 

Cost -

U00c F** 

323 

593 

17=i 

Incr. 

Capital 

tc 1500°* 

33 

97 

43S 

855 

Percent 

Increase 

11» 

17% 

24% 

28% 

Annualized 

Cost -

HOG3 ?' 

137 

288 

1741 

Incinerators -rt s.esuirinc S-.:~elemental Air 

1000 

10000 

25000 

352 

7C-5 

1310 

36 

125 

330 

11* 

ISS 

25% 

139 

363 

728 

P.23 

Incr. 

Annual 

to 1600°? 

Percent 

Intreas 

11 

28 

127 

248 

s

r; 

1 . 4 

I2S 

I - m 

10 

40 

96 

ict; 

12?: 

rAll n.onsy ncu-es in thousands of oollars 

i.i f wu » i »U i U> . w v i «••" : j.iw O »'1S kva d llilka l i« » 

,-.:• *..-..'..'.:~t ,v- ;cccr.c; reside s 1'ii.is, recuperative 

of 510°F, and tne listed flov;. The next column sho' 

incinerator operating at 16005F. The fourth column 

capital cost from 1400°F to 1600CF. 

***The annualized cost column shews the total annual 

utilities and maintenance) for 1400°r,'.75 seconds, 

listed flow. The next column shows the Incremental* 

incinerator at 1500'F. The seventh column shows th 

cost from 140CPF to 160C°F. 

capital for an incinerator c 

recovery witn an exit gas t 

ws the extra capital for a s 

shows the percent increase 

cost (depreciation, interest 

510°F exit temperature ~;.i 

• annualized cost for a siiri 1 

e percent increase in annual 

exper 

i rr. i 1 a | 

in 

ar 

i:ec 
P.24 

*"•» Appendix*-

M1x1n*firai ^ concept 1n Incinerator efficiency. Thus, a discussion 

of incinere1_BpffIciency will likely rely heavily on this concept. 

However, nlflfils-also a complex concept. Thus, discussions of efficiency 

can beccce HfWfned with technical explanations of mixing. To handle 

this difficulty, this memo only cites mixing in the main discussion and 

leaves detailed explanation cf this concept to this appendix. 

This appendix discusses mixing in three parts. The first describes 

the actual physical events involved in mixing and contrasts proper and 

improper mixing. The second discusses a related item, flow regime, and 

explains the importance of this idea in interpreting the lab scale data. 

The third analyzes the lack of a relationship between temperature and 

efficiency in the L.A. data and concludes that poor mixing was the 

cause. 

Mixing 

Mixing can be understood in terms of the two items required for 

combustion of organic compounds, high temperature and sufficient oxygen. 

In Incineration, these are provided by combustion gases and supplemental 

air. The combustion gases from burning supplemental fuel provide the 

heat to achieve high temperatures. Supplemental air, when needed, ' 

provides oxygen to combust the supplemental fuel and VOCs . 

Mixing concerns these two streams, i.e. combustion gases and supplemental 

air. Mixing involves the speed and completeness with which these two 

streams are dispersed into the waste gas. In proper mixing, these two 

streams are broken apart and Intermingled with the waste gas on a molecular 

level. In addition, this process occurs within only a small fraction of 

the incinerator residence time.. 

In contrast, in improper mixing, packets of waste gas pass through 

the incinerator intact. The turbulence 1n the incinerator fails to break 

the waste gas into sufficiently small units for intermingling on a molecular 

level to occur. Poor mixing also results if this intermingling occurs too 

late. If the waste gas is mixed just prior to exiting tht incinerator, 

then the actual residence time (R.T.) is much shorter than tht nominal 

R.T., and complete combustion may not occur. Finally poor mixing results 

if only one of the two required streams. I.e. combustion ges or supplemental 

air, is properly dispersed. For example, the waste gas may be properly 

intermingled with combustion gases, but the supplemental air flow may be 

stratified. The result would be Incomplete combustion. 

Flow Regime 

Flow regime involves the large scale gas currents in an incinerator. 

In a diagram of the gas flows 1n an incinerator, flow regime corresponds 

to broad arrows representing the macroscopic currents. 
P.25 

- • «•?» • -e-. 

Certafn-flow regimes have been labelled. In plug flow, Inlet gases 

remain wittfj fixed- vertical "slices" that travel directly from inlet to 

outlet wiW » backflow. in complete backmixing, the opposite occurs. 

Inlet gaseifcire rapidly spread throughout the incinerator and significant 

backflow occurs. Other flow regimes are composites of these, ln two 

stage backmixing, the incinerator operates like two units 1n series, 

with eacn undergoing complete backmixing. Clearly,- actual flow pattems 

rarely correspond to these idealized types, but these types can serve as 

approximations. 

Flow regime is related to poth mixing and efficiency. Specifically, 

the flow regimes most favorable to high efficiency are the least favorable 

to mixing, and vice versa. Based on engineering kinetics, plug flow 

achieves the highest efficiencies at a given temperature. However, to 

achieve good mixing and still maintain plug flow, the gases in each 

vertical "slice" must completely mix with each other while remaining 

separate from the adjoining "slices." Such a phenomena is difficult to 

create. As the gases mix vertically they also tend to mix horizontally, 

resulting in a flow pattern closer to complete backmixing. Thus, providing 

good mixing inherently creates flow patterns less advantageous to high 

efficiencies. 

Flow regime is important in interpreting the Union Carbide (UC) lab 

unit results. These results are significant since the UC unit was 

designed for optimum mixing and thus the UC results represent the upper 

limit of incinerator efficiency. This upper limit is used 1n evaluating 

the costs involved in adjusting and designing an incinerator to reach a 

given efficiency. The closer this given efficiency 1s to the upper 

limit, the higher the costs will be. 

An understanding of flow regime is required to choose which part of • 

the UC results represents the upper limit. As seen in Table 2, the UC 

results vary by flow regime. Based on the above discussion, the results 

under complete backmixing were chosen as the upper limit for the discussion 

in this memo. Though some incinerators may achieve good mixing and plug 

flow, the worst cases will likely require flow patterns similar to 

complete backmixing to achieve complete mixing. Thus, since this memo 

is considering efficiencies applicable to a U Incinerators, a conservative 

assumption of complete backmixing was required when considering the 

upper limit of efficiency. 

L.A. Oata 

The L.A. data surprisingly showed ho relation between temperature 

and efficiency. Various factors were analyzed to determine the cause 

for.this result. 

J 
-3-

1 - _._, *•.,_. _.»..«__ «««l1n# error and tht Indntretor 

S * ^Snc e tf mi ^ *"« typt of compound 

variables of rtsljtnc. «•• • '"'JL to bt the ciuse. tht sampling would 

wirt ruled-ou^ For sampling error^w Efficiency in high temperature 

have had t*JBl*2! ! ?*^n 1 ^ tlwerature tests. With over 150 

tests and ov»mimateJVIMSIIDU . For the three Incinerator variables 

tests, this l** 1**!* 1 1 * I?;! ! 1 Jilts would need to mask the effect of 

sr> . ssss«

 lyi CSJissiS-,fftet of laBP,mur' 

still seen in the increasing average efficiency. 

The refining variable is fixing A plausible explanation of ^ 

results is possible If th s variabit i s " n*;°TM; o f ttmptrature and 

two factors which allow mixing to £* * TM TM 4 „n drop with temperature, 

efficiency. First, the completeness of mixing ^ temperature. 

Thus. *^w r •ixlnj c.n off et ^effec t ^ncreas g^ ^

 c 

In contrast, the other variables

 r ^£7 na

c £ aJt $ ^temperature only 

and thus offsetting cannot °«ur. secona, ^%u 

increase the efficiency of the well mixeo por* ° t d Y0C and l1kt i y 

Since this portion contain! only part of Jnjjjco^u ^ y ^ 

fn%ortrlrt,nh^0rh:rTarrablIs1nc

C

art "?solaT." parts of th. wast, gas . 

from the affect of temperature. 
P.27 

*..' 

•v' M * • 

REFERENCES 

1. Predieggt Model of Time-Temperature requirements for Thermal Destruction 

of 01 #BOrgani c Vapors, Kun-chieh Lee, James L. Hansen, Oennls C. KcCauley, 

Union Carbide, South Charleston, West Virginia. 

2. Emission Test of Acrylic Acid and Ester Manufacturing Plant, Union Carbide, 

Taft, Louisiana, Draft Reoort by Midwest Research, May 1979. 

3. Emission Test of Acrylic Acid and Ester Manufacturing Plant, Rohm and Haas, 

Deer Park, Texas, Draft Final Report by Midwest Research Institute, 

May 1979. 

4. Stationary Source Testing of a Maleic Anhydride Plant at the Oenka Chemical 

Corporation, Houston, Texas, Final Report by Midwest Research Institute. 

5. November 8, 1979, Letter, Michael F. Weishaar, Monsanto, St. Louis.* 

Missouri, to Jack R. "imtrt U.S. Environmental Protection Agency, 

Research Triangle Park, N.C. 27711. 

6. August 15, 1979, Letter, Roger Towe, Petro-Tex, Houston, Texas, to 

Jack R. Farmer, U.S. Environmental Protection Agency, Research Triangle 

Park, N.C. 27711. 

7. March 20, 1930, Letter, George F. Martin, Petro-Tex. Houston, Texas, 

to David C. Mascone, U.S. Environmental Protection Agency, Research 

Triangle Park, N.C. 27711. 

8. January 17, 1979, Letter, Allonzo Wm. Lawrence, Koppers, Pittsburgh, 

Pennsylvania, to Don R. Goodwin, U.S. Environmental Protection Agency, 

Research Triangle Park, N.C. 27711. 

9. Set of summaries of emission tests performed by Los Angeles County personne 

• from 1970 to 1979. 

10. Control Device Evaluation - Thermal Oxidation, Jim Blackburn, IT Enviroscie 

Knoxville, Tennessee, December 1979. 
••'' < .... ' 

U\ 

P.28 

-UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

OATI: 

sumcT-. Thermal Incinerator Performance for NSPS, Addendum 

PROM: David C. Mesconeylv^ 

Chemical Manufacturing Section 

TO-. Jack R. Farmer, Chief 

Chemicals and Petroleum Branch 

After reviewing the recent memo on incinerator performance, 

(Thermal Incinerator Performance for NSPS. June 11, 1930, DCM to 

Jacx Farmer), you indicated severFPareas where further discussion was 

desired. These areas were as follows: 

- continuous compliance of thermal Incinerators 

- the impact of compound on efficiency 

• the impact of inlet concentration on cost effectivesness andj. 

eff1ci ency 

These three areas are discussed below proceeded by a summary of the 

conclusions. 

Conclusions 

In the absence of a demonstrated continuous VOC monitor for thermal 

incinerators, CPB is investigating alternate methods. After study of. 

the cost and effectiveness of several such methods, the following should 

be considered: continuous temperature and flow monitoring and bi-annual 

compliance testing and inspection/maintenance. For example, in monitoring 

temperature and flow, a company could be required to run the Incinerator 

between +50°F of the temperature, and between +20 percent and -50 percent 

of the flow, measured during the performance test. 

Detailed analysis shows that type of compound does affect Incinerator 

efficiency. However, due to the complexity of the relationship, no 

attempts were made in the June 11 memo to draw fine-tuned efficiency 

conclusions relating different efficiencies to different compounds at 

different temperatures. Rather, a more conversatlve approach was taken 

in which the efficiency conclusions were based on the most difficult 

compounds to combust. These conclusions, based on such a worst case 

analysis, would then apply regardless of compound. 
-a. i 

Detailed analysis also shows that inlet concentration affect* 

Incinerator efficiency. However, unlike type of compound, statistical 

study of th»siJfct1onsh1p between inlet concentration and efficiency was 

possible.- Be^Bron this study, the conclusions in the June 11 Incinerator 

memo are explHnd-1n both ppmv and percent reduction. This dual format 

accounts for fKe> effect of inlet concentration. 

Inlet concentration also affects cost effectiveness. One effect is 

that as inlet concentration drops the energy content of the waste gas 

drops, increasing supplemental fuel use. However, this is not the major 

effect. By far the largest effect of inlet concentration on cost 

effectiveness 1s to change the amount of VOC controlled. Over a typical 

range of inlet concentrations (i.e. 10,000 to 500 ppm) and for an 

incinerator with 70 percent recuperative heat recovery, increasing fuel 

use can increase cost effectiveness 5 to 50 percent while decreasing VOC 

can increase cost effectiveness 5 to 2000 percent. 

Discussion 

Monitoring - One CPS goal is continuous monitoring of air pollution 

control equipment. At present, we are limited in achieving this goal 

for incinerators by the lack of a demonstrated continuous VOC monitor. * 

Given this limitation, CPB is studying alternate monitoring methods, f 

such as measuring firebox temperature, to indicate Incinerator performances 

To develop alternate monitoring methods, two goals were considered. 

First, these alternate.methods should detect all or most cases of poor 

incinerator performance. Second, the methods should have reasonable 

costs and impose reasonable recordkeeping requirements. 

To meet these goals, the variables that affected incinerator performance 

were analyzed. These variables are temperature, mixing, type of compound, 

inlet concentration, residence time, and flow regime. Of these variables, 

the last three were judged of little concern when considering continuous 

monitoring. These three variables are essentially set after incinerator 

construction and adjustment and/or have only small impact on incinerator 

performance. The three remaining variables were then analyzed in more 

detail to define their Impact on performance and the ability to monitor 

them. 

Temperature was analyzed first. This analysis was based on data in 

the previous incinerator memo. Even with good mixing, the Union Carbide 

lab data and kinetic theory show that lower temperatures cause significant 

decreases in efficiency. In addition, the L.A. data Indicate that 

increasing temperature can also adversely affect efficiency, apparently 

by changing mixing. In terms of cost, temperature monitors are inexpensive, 

costing less than S5000 installed with strip charts, and are easily, and 

cheaply operated. Given the large effect of temperature on efficiency 

and the low cost of temperature monitors, this variable 1s clearly an 

effective parameter to monitor. 
P_30 

**^C - ,--* .,:^-.. ^ §£* "•;•-;-.-;,• 

As an exjmplt, a specific requirement could bt that tit Incinerator 

cannot bt oomtteVtor more than thrt; hours at an average firebox temperature 

above 50*MMl___or under 50*F below, the average temperature recorded 

during per^Rnce testing. If an operating range greater than 100'F is 

desired, a^fiajeny could perform performance tests at more than one temperature. 

The three hour time period would correspond to the period required for 

integrated bag sampling in a typical performance test. This would make the 

averaging period for temperature monitoring similar to that of the performance 

test. Finally, the company could be required to install, operate, and 

calibrate the monitor according to manufacturer's specifications. These 

specifications generally cover proper placement of the monitor. 

The next variable studied was mixing. The most likely item to 

affect mixing, given a constant temperature and an already constructed 

incinerator, would be flow. No direct field data 1s available on the 

effect of flow on mixing efficiency. However, based on engineering 

judgement, increasing flow may lead to "shortclrcuiting," where the 

increased kinetic energy of higher flow streams causes waste gas to jet 

through the.incinerator unmixed. Decreased flow may lead to the opposite. 

where lower flow rates result in insufficient kinetic energy for complete 

mixing. As with temperature, flow monitors are Inexpensive and easily 

operated. Given the potential impact of flow on efficiency, and the Iowa 

cost of flow monitors, flow rate is also an effective parameter to Z 

monitor. 

As an example, a specific requirement could be that an Incinerator 

cannot be operated for more than three hours at an average flow less 

than 50 percent or greater than 120 percent of the average waste gas 

flow recorded during a performance test. The permissible range would be 

intentionally broad due to the lack of field data on the impact of flow 

on mixing and efficiency. The upper restriction would be Lighter than 

the lower since increase flow not only may adversely affect mixing but 

decreases residence time. Any adverse effects of decreased flow may be 

offset by the increased residence time. The above discussion for temperature 

on widening the operating range, the three hour time limit, and installation, 

operation ar.i calibration of the monitor would hold for this flow monitoring 

example. 

The final variable analyzed was type of compound. Fcr most incinerator 

applications, the compounds in the waste gas are set by the process to 

which the*-incinerator is attached. Thus, type of compound is of no 

concern. However, certain applications may have differing compounds in 

the waste gas. A coating operation may have at one time a solvent with 

an MEK base, and then switch to a solvent with a toluene base. MEK 1s 

oxidized easier than toluene, and thus an incinerator which achieves 

compliance on an MEK stream may be inadequate for the toluene stream. 
nn 

The judgement on this Item 1s the** net general monitoring, requirement 

on type of compound can bt specified. Most cases will have tht waste 

gas compound*^, by the process. In those tha'. do not, considerable 

difficulty 1*iMa1oned 1n defining, in a general way, when the waste 

ges compoundpSeve changed enough to require additional compliance 

tests. For example, differentiating between solvent formulations would 

be difficult. The same generic name of solvent may show greater variations 

in composition than two different name specialized solvents. However, 

though a general requirement on type of compound cannot be set, specific 

requirements may be desired for certain standards. 

Temperature and flow monitoring do not measure Incinerator performance 

directly. Thus, concern exists over the long term stability of Incinerator 

performance, even with temperature, flow and type of compound held 

constant. Data on this issue is shown in Table 1. The top part of the 

table shows data from L.A. County where the same Incinerator was tested 

1n different years. The bottom part lists possible Incinerator malfunctions 

that could affect performance, without changing temperature and flow. 

Based on Table 1, incinerators, 1f properly designed and adjusted, 

are judged to have fairly stable performance over time. Tht I.A. units 

showed only small changes in efficiency over time. The efficiencies of 

these units changed less than two percentage points over sevtrrl years, i 

except one case. In addition, the listed malfunctions are judged to ? 

occur infrequently. This 1s based on several factors. First, these

 ;! 

malfunctions involve non-moving parts subject to littl e wear. Also, the 

typical waste gases are not highly corrosive and the typical Incinerator 

fuels, natural gas and fuel oil, have low sulfur and ash content. 

Finally, even though Incinerators undergo wide temperature swings, 

incinerator components are designed to withstand these changes, given 

proper cooling and heating of the unit. 

The above conclusion should not be overstated. Though fairly 

stable, all four L.A. date sets show some drop in performance over time. 

And though improbable. Incinerator malfunctions are not impossible. 

Thus, the conclusion from the data 1s not that no additional requirements 

are needed over temperature and flow monitoring. ' Rather, the conclusion 

is that the costs and recordkeeping of additional monitoring requirements 

must be carefully balanced against emissions potentially prevented by 

them. 

After this balance was studied, two additional requirements were 

considered. These are bi-annual performance testing and bi-annual 

inspection and maintenance (I&M) for incinerators. The performance 

testing would follow the method specified 1n the standard. The I a M 

would involve visual Inspection for items such as corrosion and firebox 

deterioration, calibration and testing of control Instrumentation,.and 

so on. Such I&M could most likely be performed at the same time as a 

process turnaround. 
These t«e additional monitoring methods would effectively dtttct 

drops in infitoerator performance not detected by temptr»turt and flow 

monitorinf^JSgrformence testing 1s thw most direct mec.s of detecting 

ooor efflcjffej.. Tht I & M will catch drops in performance by spotting 

equipment failures or impending failures that could lead to poor performance. 

The I & M hds the added advantage that impending failures which could 

lead to incinerator shutdown would also be spotted. The two year period 

for compliance testing and I & M 1s based on the rate at which incinerator 

performance is likely to deteriorate. The two year period for I & M also 

corresponds to the typical time between process turnarounds. Thus, with a 

bi-annual I & M the incinerator I & M could be performed at the same time 

as process equipment I & M, and it would not be necessary to shut down 

the process just to check the incinerator. Finally, the timing of the 

performance test and the I & M are not linked. They can be done together 

in any order or apart. 

Type of Compound - One factor which affects incinerator efficiency 

is type of compound. The June-11 memo on incinerator efficiency excludes 

this factor from its conclusions, but discusses only briefly .the reasons 

for this exclusion. This section discusses the Impact of this factor on 

efficiency and explains in more detail the reasons for its exclusion. 

In terms cf the impact of compound on efficiency, the available ; 

incinerator data does show a moderate Impact. The Union Carbide lab 

data demonstrates this most clearly. In cases where different compounds 

were incinerated at the same temperature, residence time, and flow 

regime, variations in efficiency of up to 5 percent points occurred for 

temperatures above U00*F. At lower temperatures, the efficiency 

variations increased up to 20 and 30 percentage points. 

However, as a practical matter, including compound as a faetor in an 

efficiency conclusion would be difficult. First, a precise quantitative 

relation between compound and efficiency could not be determined. As 

with mixing, no single value could be assigned to an Individual compound 

to represent ease of combustion. Thus, analysis of the relation between 

efficiency and compound was limited. Second, even if a relationship 

could be devised, i t would be complex and difficult to apply. The 

relationship would likely involve kinetic rate constants, autoignition 

temperatures, factors for molecular configuration and structural groups 

and similar variables. 

To avoid these difficulties, an alternative approach was taken. No 

initial attempts were made at drawing a fine-tuned efficiency conclusion 

showing differing efficiencies at differing temperatures for different 

compounds. Rather, a conservative approach of choosing a simple set of 

incinerator conditions and efficiencies based on the most difficult 

compounds to combust was pursued. This approach proved successful. 
Several factors aided 1n tht success of this approach. First, the 

avail ablav tes 

which tes*. 

aromatic*^, 

such as ME K 

and ethyl ami 

Qjyered a wide range of compounds. Tht compounds on 

available Included C, to C- alkanes and olefins. 

benzene, toluene, and xylene, oxygenated compounds 

ropenol, nitrogen containing species such as acrylonitrile 

chlorinated compounds such as vinyl chloride, with 

such a range of compounds and the consideration of kinetics, it was concluded 

that worst case compounds had been taken into account. The second 

factor was the discovery that increasing combustion temperature resulted 

in only negligible energy penalties and moderate cost increases. Thus, 

choosing a higher temperature to cover the worst cases did not make 

Incinerators unaffordable or too energy intensive. 

Inlet Concentration - A second factor which affects efficiency 1s 

Inlet concentraton. Unlike type of compound, an allowance for this 

factor was Included in the efficiency conclusions. Specifically, these 

conclusions included not only an efficiency of 98 percent but a minimum 

exit concentration of 20 ppmv by compound. Thus, as Inlet concentration 

drops, the minimum ppmv lowers the efficiency required. For example, 

with a 500 ppmv Inlet concentration for a waste gas containing oxygen, 

the 20 ppmv minimum translates to a 96 percent efficiency; with a 250 ppmv 

Inlet, a 92 percent efficiency. This section explains 1n more detail t 

the reasons for this allowance for inlet concentration. I 

The test results from L.A. County form the major basis for this- ? 

allowance. These results show a strong trend where lower inlet concentration 

results in lower efficiency. For example, for Inlet concentrations less 

than 1600 ppmv as carbon, the median L.A. efficiency was approximately 

92 percent. For inlet concentrations between 1600 and 2400, the median 

L.A. efficiency was approximately 94 percent. For Inlet concentrations 

above 2400, the median efficiency was approximately 97 percent. 

Kinetic considerations also support the allowance for Inlet concentration. 

The most likely kinetic model where inlet concentration does not affect 

efficiency is a first order model. However, available-literature Indicates 

that combustion follows complex reaction mechanisms. ' In cases, these 

r.echan.sms can be fit to a first order model. However, as a general 

rule, these mechanisms, which Involve chain reactions, free radicals and 

multiple pathways, cannot be reduced to first order models. 

The June 11, 1980, Incinerator memo concluded that the L.A. Incinerators 

did not all achieve proper mixing. This Improper mixing may have caused 

or influenced the relation between efficiency and Inlet concentration in 

the L.A. data. If this is the case, then an allowance for Inlet concentration 

may permit lower efficiencies than are actually achievable in incinerators 

with proper mixing. However, the possible effect of poor mixing on the 

relation of efficiency and inlet concentration remains just that, possible; 

no conclusive statement can be made. Given this, a more conservative 

approach was taken and .lower efficiencies for lower inlet concentrations 

were allowed. 
:

-y*& ' * w 

Inlet concentration also impacts cost effectiveness* 1.e> cost* pt* 

unit wtigMflHLtoatrp *

1,d * The precise.impact depends on molecular 

weighti- tfle^Hfeof tht Incinerator and tht ratio of waste gas energy 

content-to «B f Figure 1 show these impacts. 

A surprising conclusion in the analysis of inlet concentration vs. 

cost effectiveness is the role of supplemental fuel. The increasing 

cost for supplemental fuel as inlet ppm drops 1s not, a major factor in 

cost effectiveness. Incinerator size and the amounr of VOC being destroyed 

are much more important factors. An Illustrative example is a 5000 SCFM 

incinerator burning benzene in nitrogen. The extra fuel required when 

dropping the inlet contrition from 5000 to 500 ppmv increases the cost 

effectiveness only 20 pereent. The fact that only one-tenth the benzene 

is being destroyed for about the same cost increases the cost effectiveness 

1000 percent. And decreasing the stream size to 1000 SCFM Increases the 

cost effectiveness about 300 percent. Clearly, Increasing fuel costs at 

lower ppmv is only a minor factor. 

1 Rolke, R.W., et. al. Afterburner System Study, U.S. Environmental 

Protection Agency, Report S-14121, Shell Development Company, 1971, i 

2Barnes, R.H., et. al Chemical Aspects of Afterburner Systems, IERL Repoft 

U.S. Environmental Protection Agency, EPA-600/7-79-096. Betelle Columbu* 

Laboratories, April 1979. • * 
P.35 

long Term Incinerator Performance" 

• J . ^ . . • • •_,-•__ _ 

,* • * _ .*_. - . . -» -.'- ._ __!•_____•___. (.;-'-J 

Company 

A . L.A. Test Oata* 

Oate? 

• •:. W •.-•••' ' 

Inlet. Outlet 

(ppmv carbon) 

X VOC 

Destruction 

Flow(SCFM)/ 

Temp. (OF) 

•ay & Night 

"anufacturing; 

Hasteel, Inc. 

National Can 

national Can 

1754 

2442 

2443 

2236 

2402 

1430 

1746 

1451 

1746 

10-30-73 

7- 7-76 " 

8-10-78 

5-12-75 

2-17-76 

6-10-70 

3-21-74 

6-10-70 

3-21-74 

443 

1030 "" 

716 

6020 

5860 

4900 

7370 

3500 

6247 

7370 

33 

" 9 1 

94 

52 

71 

31 

104 

22 

82 

79 

92.5 

91.4 

87.3 

99.0 

98.9-

99". 4 

98.6 

99.4 

98.0 

98.0 

3270/1300 

2020/1300 

2050/ -

1210/1260 

4150/1375 

2520/1500 

1590/1500 

4620/1460 

4660/1420 

.4650/1525 

Part 3 - Possible Incinerator Malfunctions** 

'alfunction Cause Possible Effect on VOCControl 

Firebrick Deterioration 

Insulation Loss from 

Incinerator Exterior 

Corrosion of ducts, 

baffles t other 

exposed metal 

Plugging of Burners ;;?.. 

breaking of Recuperative 

Heat Exchanger Seals 

Improper heating & cooling 

of incinerator during 

start-up & shutdown; 

firebox temperature too 

high 

General weathering t 

corrosion from rain, cold, 

Incinerator start-up & 

shutdown t so on 

Ash, adds, salts, etc. 

in fuel or waste gas 

Deteriorated wall allows local 

heat loss resulting in cool spc 

1n firebox, and thus potential! 

lower destruction efficiency ir 

those spots 

Same as previous; insulation T 

leads to local heat loss & coo 

in the Incinerator 

Ash & carbon buUd-up 

Severe corrosion of metal part 

affects the gas flow patterns 

through and around them, poten 

affecting mixing & thus effici 

A plugged or partially pluggec 

affects the flow patterns & 

temperature profiles in the f 

potentially lowering destrucV 

efficiency 

General corrosion; tamper- Inlet waste gas leaks into th 

ature warping from hot spots flue gas without passing tnro 

in the exchanger, improper the firebox, 

heating & cooling during 

start-up & shutdown 

*7ne iisteo oata are from incinerators wnicn wtrt testeo in more than one year. 

-The listed malfunctions include only those which would likely not affect temperature at a 

sinele point firebox temperature ronitor or inlet/outlet flow. 
_E_36 

4»* . 

. i-'^-^i'Ji—. 

»3taR__!_^aj__aDap.r\j^5vii^_.^ii3i sjaexi" aac^TX _*rJ

^^,_^_^^,r:.:^i-~, 

5_3 ^ ' r 

4v'.. i 

'iffP ^ 

8 

o 

1000 2000 

PPMV 3Y C0MP0UN0, MW • 80 

Figure i - Cost Effectiveness for Thermal Incinerators by 

Inlet Concentration and Waste Gas Flow 

300Q 

 
j P.37 

>.«rw < rfgurf f> 

c,^w?-*' 

Explanation 

f. *•*«. 

••cr, 

• -

Figure-tjUptthecpst effectiveness of thermal Incinerators by Inlet 

concsntratletflflKiste>.ajM flow. Tht cost effectiveness 1s in hundred dollars 

ptr 2000 pwiS^Bp?Inlet concentration is ppmv by compound; and the flow rate 

is in SCFM. T|_pjpsti in the figure assume a waste gas deficient 1n air, and 

a compound witfTa molecular weight of 80 arid a heat of combustion of .15,000 BTU/lb VOC 

The thermal incinerator ooerates at 1600°F and .75 seconds and achieves 70 percent 

recuperative heat recovery. 

The figure can be used to approximate cost effectiveness for situations other 

than that described in the above paragraph. For compounds with different molecular 

weights, the x-axis scale should be increased by 80 over the,molecular weight of the 

compound. For example, for a compound with molecular weight of 40, the x-axis scale 

would read 2000, 4000, and 6000. For cases where the waste gas contains sufficient 

oxygen for combustion, the cost effectiveness should be decreased by the following 

percentages: 

1000 SCFM 

2500 SCFM 

5000 SCFM 

10000 SCFM 

25000 SCFM 

7X 

14X 

21% 

26X 

30* 

This adjustment accounts for the smaller size and lower fuel requirements oJ t these 

cases. Finally, for cases where the combustion value of the stream per pound of 

VOC is higher, the below listed decreases approximate the costs. These adjustments 

**____.* ___.___.___. AV* . •««_. _._mm assume 30,000 BTU/lb VOC, 

for ppmv <500 

for ppmv between 

500 & 3000 

for ppmv >3000 

No adjustment 

1000 SCFM 5X 

2500 SCFM 10X 

5000 SCFM 15X 

10000 SCFM 20X 

25000 SCFM 255 

No adjustment 

This adjustment accounts for the lower fuel use at higher BTU/lb levels. 

_