UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

Office of Air {)uality Planning and Standards 

Research Triangle Park, North Ca•o]ina 2771] 

ThePm•l Incinerators and Flares 

Jack R. Farmer, Chtef/•l_• Chemicals and Petroleu•"B•ch- (MI)-13) 

II-B-31 

The attached •atertals provide, guidance on the performnce, of 

•ic• a• evaluat• f• a •PS or •. 

Da•e Nascone's two memoranda on themal incinerator performance present a good summary of all the information we currently have on 

thermal incinerators. Most questions that may need answering for a 

lISPS or NESHAP should be addressed in these two memoranda. These two 

mmm-anda should be added to the docket of any standard where thermal incinerators are included as a control device tn a rngulatory alternettve, 

A report ts being prepared by EEAwhich is an assessment of a German 

.•tud¥.on fl•; ..The.•_.•wt]|.•a!SQ:be distrtbuted:.as scan. as 

At•aclments 

Addressees: 

CPD Section Ch|efs and Lead Engineers SDB Section Chtefs and Lead Engineers •ob Ajax 

0tin Bath 

Don Goodwi n 

Fred Porter 

roe Standards Contractors 

Tom 6t1• 
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

Thernml Incinerator Pe.-formance for •6PS 

David C. •scon• 

Ch•cal •nufactur•ng •, •B 

Jack R. Fair, •ef 

:h•cals aM Pet•le• Br'•ch 

•er •e p•st f• •n•s, • has investigated incinerator efficiency, 

efficJenc• 

cos• •nd fuel use. • pu•se of this stud• has •n to pick an •at •p•sen• the h•ghest c•t•l level •chJewble b• •1• • incinerator, consisting •vsJl8b]e •chnolo•, cos• •nd ene• use. 

•c 1 us tons 

21:) 

Based on our study, we conclude that 98 percent VOC reduction, or ppmv by compound exit concentration, whichever is less stringent, is 

avatlab|e 

the highest control level achievable by all new incinerators, considering technology, cost and energy use. Thts leve'l is expressed in 

_.c•_c.en.t_r•t!o•s 

both percent reduction and ppmv to account for the leveling off of exit .as:•..a:]et•.c•m•eetratiees...clrop.:• ..This •vel..-is. based.•n.. 

time. 

lnclnerazor operation at a maximum of 1600"F and .75 second residence 

recuperative 

The costs 

heat 

and energy use of achieving thts levelare based "on 

to 510"F. 

•covery capable of lowering the flue gas temperature 

in efficiency, 

Fr•a our stud•, we also conclude, that mixing ts a critical factor 

such 

a factor of equal or greater importance than other factors as temerature. After surveying available means of improving mixing,•e conclude that incinerator ad•iusta•nt after start-up is the most 

are based 

feasible and efficient. The control levels tn the previous paragraph on such an adjustment. 

F•IOui" s (u • ( also conclude that. With proper heat USe Of recuperative recove• (•R). no sl•iflcant in c•ustlon •er• l•naltles occur •ith changes 

l•It$ of l•t-•.c•:and 

•rat•re. The reas• is that. based on the technical preset fuel: costs, the _optl• incinerator exit 

t•m)erature. 

$•as •rat•re is sli•tly above 600"F, regardless of conOustion 

C•$t•-•;atU•. 

Sln• .!nci•r•or fuel .t•e de4)end$ • ex-it gas.-and not 

of Increa$1no 

•R can essentially eliminate • fuel l•nalty c•ustl• •rat•re. 
-2- 

D| scuss•on 

This sectio• discusses our dal• and findings on incinerator efficiency, 

cost and fuel use, and presents the logic behind the choice of the above 

control level. This section has three parts, one on efficiency, one on 

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

section are at the end of the memo. 

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

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

a control level applicable t• all new incinerators, *yen the worst 

cases. In reality, there wi|l be a distribution of cases from worst to 

best. Thus, in •any situations, incinerators will achieve greater than 

98 percent, or less than 20 ppmv, control at less than 1600"F and 

-75 • residence ti•e. 

Second, this discussion lists specific incinerator conditions 

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

i.e. to calculate cost, fuel and emission tr•acts. This memo does not 

reco•wend that these conditions be specified in regulations. As just 

noted, this set of conditions represents only oneof men• with which 

to achieve 98 percent reduction or 20 ppmv. Thus, the control levels in 

the above conclusions, not the incinerator conditions, should be the 

basis for regulations. 

Third, this discussion focuses on thermal incineration since this 

control method has the widest applicability to control of ducted 

emiss•,ts .Tais.mema-does net•c•lude that. tnclnera•ton. !s a•p|•¢a_bl.e. 

to all situations or that, when applicable, incineration is the only 

feasible control method. 

Fourth, this discuss|on covers incinerators operating with relatively 

constant inlets and flows and with waste gas flows greater than GO0 scfm. 

This in general tncluoes incinerators on solvent drying operations, 

polymer production plants, and.air ox'..dation units. For incinerators 

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

liquid storage tanks, the fuel and capital cost calculations in this 

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

the above conclusions on efficiency, these efficiency conclusions are 

Finally, this discussion covers new incinerators applied for control 

of VOC fo, .•xtdant reduction purposes. Existing incinerators may not be 

physically capable of achtevtn• the.. l•mperal;ure, r•stdence time and heat 

recovery conditions listed in this memo. Thus, these incinerators may 

not he able to reach..g8 percent or 20 .ppmv..Oa the other hand, incinerators 

for control of toxic or haza•lous VOC need not be 1tin|ted to 98 percent 

or 20 pp•v. As discussed helow, .htgher efficiency incinerators are 

possible for a•l comounds with so• devel.ot•ent and design .cost. 
-3- 

•- The available data on incinerator efficiency is described 

in Table I and summarized in Tables 2-4. The data include results from 

lab scale incinerator tests conducted by Union Carbide and from field 

tests run by EPA, LOS Angeles County and chemical companies. 

These data were analyzed to determine 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 w•rk. wa• chosen,for..th.•s ana]ys•s since, its sin11 size and careful .design be•t assu•ed consts•en• and 

proper mixing. 

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

results show moderate increases in 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 in Appendix A 

on mixing and flow regime. Ftnally, the results show that a given temperature does not correspond •o a given efficiency. Rather, increasing temperature increases efficiency, by narrowing the •'ange over which effictenctes fall and increasing the average of the range. 

The nex• analys•s focused on mixing. To accomplish this, cases 

•erelptckedwbere.a11 variablesexceptlmi)dngwe•e.held_cons,cen•.or l.•.• 

accounted for in other wa•s. It was then assumed any changes in efficiency would be due to changes in mixing. 

The case most Jtrectly showing the effect of mixing on efficiency is presented in Table 3. The Petro-tex data show the efficiency changes due to two mdtf!cattons of the incinerator after start-up. These modifications increased efficiency from 70 percent to over gg percent, with no change in temperature. The modifications include repositioning baffles and burners, and rerouttng inlet combustion air. 

A case indirectl• showing th• effect of mixing is presented in Ta•b]e 5. These_da•. cmtzare.the efficiency of-.the Roll-.and-Haas .(RSH) tnct•re•r tn ¢•usttng f•r s•tfic ¢•• wt• •at-of the Union •t• 1• •tt. T• lab •tt clearl• •om •e • unit. T• 

• f• • • a• •s• en •e s• •re•, •st•nce tim and •nle2 s• condtt•sj • m• c•le• •xtng of the •ab •it ts Jud• •e ca•e of •e differing efftcte•t•, 

•t•r •se tndt•l• s•tng •e effect of mixing is p•sented tn Tab!e 6, •se • a• a •tal 11st of L.A. •t• •sts • 

efftct•c• d•d or •t• t• s• wt• tnc•astng •rature. In •] •hts •sult •cur•d in 21 of •e 50 L.A. • •sts in which 
-4- 

the same inctneretor •s •este• at different temperatures. As above, al1 factors except afixing r•r•ined t•.• s•me or can be accounted for in other •ays. Thus, chan•es in •he com•lete-,ess of mixing are judged to be t•e cause of the resutts. 

The final analysis was designed to study the effect of all variables at once. The L.A. data were chosen for •is analysis since the L.A. units operated over a wide ran• of each :f the variab,es of interest. In addition, the L.A. re.s•Its represented :he largesC body of available efficiency data and zhus were the most amenable to statistical analysis. The results of the ana!:vsis of the L.A. d•ta are show• in Table 4. These results show a •eak relation between efficiency and inlet concentration and no relation betwee;• efficiency and temperature. 

The temperature vs. efficiency.res.ults .are. surprising. Kinetic theory.and 

the 

t•e .lab scale results show large IBcreeses inefficiency over 300"F range in Table 4, but in fact no such increase occurred in the L.A. data. Detailed analysis of th•s data •oints to poor mixing as the cause of these result. This ana•ysts is described in Appendix A to this memo. 

Important The conclusion from these three analysis is that mixing is the most variable in incinerator efficiency. This is based on the large changes in efficiency in the R&H and Petro-tex results and the ability of mixing to mask the impact of temperature in the L.A. data. This is not to conclude that temperature, residence time and other variables have no i,...•f]uence important, on efficiency. These var'.'•b]es do have an though smaller, influence. 

energY•ned in the Hydroscience report on theme1 inctneretton. Selected parts of these data are shown in Table 7 and 8. These data were used to analyze the relations between capttal cost, energy use and 

also 

heat recovery. 

analyzed. 

In addition, the costs of efforts to improve mixing were These analyzes are discussed below. 

and 

The first analysts studied the cost trede-offs between heat recovery energy use. The resu|ts of this analysis are shown in Table 7. This 

increasing 

table lists the tncremnta• capita| costs and energy sa':tngs with 

which. recuperative heat recovery (RHR). The 70 percent I•R case, 

the maximum 

•¢orres _pp.,dS ¢•.. a •11•._ gas .temperature sl|ghtt• above .•XI•-F, represents feasib]e |evel of recovery. Beyond 70 percent RHR, problems arise with precombustion in the heat exchanger and with condensation of water in the trlue gas and possible corrosion. 

The resu•l:s on Table 7 indicate that the maximum t'eastb|e RHR should be used. Up to. this -max•mJa, except-for the t000 scfm case, the capttal cost of each increment of RNR is more than offset by the incremntaI erie _rgy. savings.. The basis for these savings is tee increasing cost of 
-5- 

energy. In older designs, based on cheaper fuel, cost savings fr•, heat 

recovery were not large enoJ•h to justify maximum IiHR. Rowever, with 

escalating fuel co•ts, e×tr.•-c•pita• equipment has become cheaper than 

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

hea• recovery, negligible energ}, penalties occur with increasing combustion 

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

on exit gas temperature, no: combustion temperature. And as noted 

above, the optimum exit c•s te .m•.rature is slightly above SOD'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, wlth'optlmma RHR, increasing combustion t•-•aperatures will lead to negligible increases in 

energy use. 

The Second analysis concerned the capital cost differences between incinerators designed at 14OD°F and 1600"F. The results of this analysis are shown in Table 8. These results show m•derate increases in capital costs and small to moderate increases in annuallzed 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 ana]ysis concerned the cost and feeslbl]Ity of various methods to improve mixing. Four methods were studied: pilot plants, |ab work, engineering design and adjustment after start-up. 

.Pilot..p|a•t.work is •ud•e•.• too .exp•n:i•IYe.... The costs, involve• .in construCtIng and •}pe•ating -fJ•-pii•t-plant unit, providing a waste gas stream, and col]ectlng and ana1•rzleg 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 Inc|nerators, 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 a•e not feasible. Lab work provides good data on kinetics, but no useable data on m•xing. Engineering equations are useful in many situations, but few such equations exist for m•xlng. The number of tra•,s in a distillatlo• colm• can be reasonably calculated; the nt•r 

The final alternative, adjusting the incinerator after start-up, does al•e•r-both affordeb•e and-feasible.--S• an ad•us•n•-•uld involve •sttt•ing baffle, a•usting •c• and •rfomtng si•lar •Sks •ht !e .•r!.ng. effacing, •ra•.•d s•]ar., va•les. •ch a •• a•li• to tnc•to• the •m adJus•n• •hat p•cess •ut•nt •tm a•r s•-• •d •ld t•olve the sa•, m•rate tt•. e•t•, .• •s•. Ft•]•, •e s•c•s of such a pr•edu• h• b•n •stra• by Pet•x. 
Control Level l•sed on the above t•tndtn•s, a series of c•clus•ons 

• •ad • t• c•tce of • •ent •uc•, o• 20 

(98/•) as •e h•es• con• level ach•ev•le •o• all n• •nc•ra•, 

conspiring •va•lab•e •ch•lo•, •st a-• e• use. •e •clus• 

a• •iscuss• •1•. 

First, Incinerator combusl•on •e•per•ture has lttt.le impact on cost 

and energy effectiveness •t•os. Th•s ••on •3 • • •he • 

c•s •th t•ra• that •cur •n • • •t•, •ly a•ual•zed 

cost, ener• use and V• c•t•l efficiency, •at rake up •e ratios. 

• d•sc•sed a•, •e • tt• all •nc•ase less t•n 15 •rcent 

• •e•a• over a I•'F • I•F ran•. S•mle m• s•s •t 

su• sm• c•n•s •n • ••n a• •na• of • c•t and 

cos• and essentially • c•n• •n e• •e (s• T•e 2 and 8 and 

p•v•s d•scussi•), a I•'F to 16•'F c•n• tn •• •es 

cost •r •und V• c•t•!l• only 5 • 10 •nt a• ac•lly decreases 

ener• •ses per •und V• cont•lled. 

Second, the highest control 11m•t should be based on |nc•nerator 

operal;•on at •600°F. Th|s conclusion |s based dtrecl;ly on the f•rst, 

•.e. that over the range of •ntemt temperature does not adversely 

affect cost or ene•w effecttvenoss. S•ven •s, h|gher temperatures, 

with htgher control eff|ctenctes, ar• preferred. 

Thts conclusive" on operating t•q•erature ts also based on the 

--•,ect•caT.-tluflts on.--ueta] ;recupera•ve-.hea•exchange•-,--8asedenthe 

logic |n the preceding paragraph, there |s no upper ]tuflt to the combustion 

temerature which should be used. Hemever, above 1600"F, ceraadc recuperative 

heat exchangers are required. Since these exchangers are sere comlex 

and costly, and :ess t•ptcal, than hera1 Oestgns, the dectston was made 

not to rely on *.hem tn considering the achievable control levels. Thus, 

160•F ms chosen for the |nctnerator operating temperature. Th•s 

conclusion •s further suppor•ced by the high control levels found 

achievable at thts te•pereture, as discussed below. 

Third, and f•nally, 98 percent VOC reduction, or 20 ppmv by compound, 

whichever ts less stringent, repments the highest a•.htevable control 

1eve1 fo•-.•ll.ne• .•nc•nerat•r•;.-•ns.•Ser•ng av•.•lable-technelegy., cost 

and enor•v use. Thts fs based on |nctneretor operation at 1600"F, as 

discussed tn the preceding perag•ph, and on a•us•tmant of the •nc|nerator after $•a•t•up, as d•scussed tn .the s.ectto• on cost. The dual statement 

of the conct,s on, t.e.-.as percen: red,ctt or accosts he 

observed.fall-off of efftc|enc¥ at lo•er tnlet concentrations. The 

98/20-numers l•eeselvesuere p•cxed by analyzing three•fferent co,•ol 

levels, 99 percent or 10 plxav, 98 percent or 20 ppmv, and gS percent or 

30. ppav. 
failing 

Second, the difference between 65 percent failing 99/10 and 43 percent 98/20 is larger than e direct comparison of the percentages would reveal. At 98/20, not only did fewer units fail, 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 is 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 forthe worst case is considered. The crucial point 

those 

is how close a.gg/lO level pushes actual field unit efficiencies to of the lab unit. Lab unit results for complete backmixino throughout the range 99 range at 160O°F, meaning a 9g/lO level would •orce field units to almost match lab unit mixing. Appendix A describes the reasons the complete backmix results were used. Backing off *-o 98/20 

increases 

increases the margin, especially for the worst cases. Given that exponential may occur in costs to improve, mixing, as .field units approach lab unit efficlencies, ..: 

i,•rove mixing 

a drop from 99/10 to 98/20 may decrease costs to in the worst case• by an order of magnitude. 

'-•-e--gS/•O-ilb•el was judged too lenient. The only data inCicating such, a low efficiency was from L.A. All other data showed 98/20. The nonoL.A, data and lab data meet 98/20 and •he Pe*-ro-tex experience 

addition, 

shewed-that .•re.te._ ed•us1•ent can ihcrease-.efficle•y abov-egB.- In in the previous discussion j..u.dged, _l;o. fi•.ve on efficiency, the L.A. units .were poor_ mixing T•e..mi-xing .defici.enc•res were-l•rae--enough-to mae-k the-effect of increasing temperature. Thus, it is ju.dge• that 98/20 could be reached with ..moder.a_.te e•ustment a•d .that a. 95/30 level would represent.a Criteria. no• based on thebest available unit• consideri#,g cost, enero.y, and environmeni•1 impact. 
Table l 

Description AJailable 

incinerator Test Data 

86•.; are described the aJailable incinerator test data. Four sets of 

such data are •resent. Thes• sets are lab scale incinerator dat• from tests 

by Union Carbide and field unit data fro• tests conducted by EPA, chemical 

c•pa•ies and L.L. County. 

Union. Carbide Test Data l- These data show the co•..b:•stion efficiencies achieved 

o• •S organic co•.pounds in a Jab scale incinerator operatin• between 8DD and iSODOF 

•2 .• :o 2 second residence time. The incinerator consiste• of a 130 centimeter 

t•i- •t.= t•be in a bench size tube f•rnace. Outlet analyzes were done by direct 

rout:y; of :he incinerator outlet to a FID and GC. All inlet gases were set at 

IOOD pPmv. 

EPA Test Da•{'•hese data show the co,.•bustion efficiencies for full scale 

incinerators on air oxidation ve•ts at three chemical plants. These three plants 

are the Unit•n Caribde, Talc, Louisiana, and Roh• & Haas, Deer Park, Texas, 

acrylic aci= =nits and the Denka, Houston, Texas unit. The data "or 

Unior Carbid• includ• test results based on t•o different incinerator temperatures 

and the dat• frc• R•ha & Haas, results fro• three te.•peratures. In all tests 

integrate• )•s •ere use• for s•pling and a GCI•ID •as used for organic 

analysis. 

5,6.7•8 Ohemic•l C•pany Test Data These data are fr• tests performed by 

chemical c•a•ies on incinerators at three air oxidation units. The com•anles 

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

Petri•tex •% their oxi•eiive l•tadle• unit at •$I•, Texas, •K• at 

thelr•leic anhydride unit at )ridge•ille, Pennsylvania. The •nsanto 

incinerator );ms both liouid and Qasecus •astes from the acrylonitrile unit 

•,,d Li)e Kuppers incinerator is actually a boiler adapted to burn gaseuus 

in all tests, analysis .as •rfor•d by GCRID. l•ne sa•,•ling was performed 

as follcwws: 

MOnsanto Cold water scrubbing AN, ACR, HCR; metal sa•le bo•s 

remaining co•x}•nds 

Petro-tex- Integrated bag inlet; glass syr'nge outlet 

Noppers- Glass s•.m•le bombs and charcoal tubes 

L.A. •unty Test I)ata g- •he,.•t; are.fr•over 2• tests.byL.A.•nty 

on v•rious •ste gas incinerator, •st of •ich are on coating operations. Data 

fr• 1(7 tests •re used, •ith the r•inin• tests being discarded since ba•-up 

•ta •re •jssin•I the incinerators were catal•ic units or similar reasons. ]n 

•he L.A. •.a, •,y fl•, t•eracure, and inlet and outlet VOC c•n•e,tratlon 

are reposed; data • c•ounds and residence ti• are not present. 

[•-•t• lit• g•s.c•l-ind•..• us•f• s•li• and •iO•!onto CO 2 
Table 2 

Results Union Carbide Tests* 

Destruction Efficiency 

Under State• Conditions 

F]o•.,' •em•erature 

Regime** 

Residence Time/Co•pound 

.75 seconds 5 & 3.5 second; 

Ethyl Vinb, l 

Acrb'l&t• Ethanol Ethylene Chloride Ethylene 

T•;•-S+• 13O• 99. c 94.6 92.6 78 .6 •7.2/97.• •a•kmixin• 14Ou 99.9 99.6 99.3 99.C 9•.6/99.8 

ISDO 99.9 99.9 99.9 99.9 99.9/99.9 

16DO 99.9 99.9 99.9 99.9 99.9/99.9 

Co•..•lete 13DO 9•.9 8•.8 84.4 69.9 78.2/91.5 Baci:mixin• l•OO 99.7 96.8 95.6 93.1 93.7/97.8 

iS•O 99.9 99.0 98.7 98.4 98.0/99.0 

I•9D 9•.9 99.7 99.6 99.6 99.4/9•.B 

Plug Flow 13• 99.9 99.9 99.5 90.2 97.3/99.9 

%•OD 99.9 9g.g 99.9 99.9 99.9/9•.9 

I•0• 99.9 99.9 99.9 99.9 99.9/99.9 

%•OD 9B.9 99•9 ..9•.9 99•.9 99.9/99.9- 

*The results • the Us, Zion Car•i• work are presented as a series of equations. These equations relate destruction •fficienc• to t.•erature; residence time and flow regime f•r each of l• co•poun•s. The ef{iciencies in this table were calculated frun 

these e•uations. 

•* Three flow re•i•es are presented, two-stage back•ixlng, complete back•ixing and pluo flm,,. T•;o steoe ba•kmixin• is considered • reasonable approximation of actu•l fi•O units, •ith c•le•e back•ixin• and plug flow representing the extr•es; The subject o¢ f]o• regime is further discussed in Appendix A. 
Table 3 

Results EPA and Company 

Incinerator Tests 

Residence 

Tim•/In].et 

Flow 

Temperature •:u•-ber of 

(FO) Test Rums 

Inlet Outlet 

VOC V0C % VDC • 

(ppmv)*** (ppmv) Control 

b•icn 2 to 3 sec/ 

C•rbide 20,600 

1160 6* 11900 243 96.1 

1475 3* 11900 10 9g.9 

Ro•:n & I sec/ 

Haas Tank F•rm Vent, 

Oxidizer Vemt, 

(0XVi-=•,OO0 

1425 

1510 

I•5 

TFV 25•O 1330 82.6 

OXV 11600 

TFV 2600 150 •8.3 

OXV IZBO0 

TFV 2410 25 99.7 

OXV 122O0 

Denka .6 sE:.Z•,DDO 950 13 98.5 

T.•nsan%o (Unit }::e) Confidential 

Koppers i• .6 se:/3•:,OO0 IBO0 

Uni: 1-6" Conf. 25 >99 

•it 2-8"* Conf. 47 >99 

Iniet-4 •* 

Outlet-6* 

850 Set I 7 99.0 

Set 2 11 97.2 

•:L• •-•.ex .6 sec/la,4OO 1•,00 •IA SoL 1 10300 1000 70.3 

Set 2 10650 2i5 94.1 

Set 3 10300 10 99.6 

*•ling ¢onducte• •th grab s•ple bc•rd}S or S•n'tnges. ..• 

'-•'*I/OC • not Inc•u:e methane of ethane. This definition of VOC is different fro• that 

use• in ea-lier •.•,.•s or EPA tests, and thus results reported here •i differ fro• results 

in the ear]ier•:o. 

• •eSt•ction is by •ei•t perc•t. 

"The •ta •n Set i an• • for Ko•pe• were taken dur•n• different ti• periods. a• •t1• Y• for •et•-tex.r• •s • •thane. The data in S• one •re 

taken prior %O adjus•n% of the inci•rator; the data in sets t•o and three, after 

adjus•n:. The s•e:ific alter•ti•s • b• Pe%r•tex a•e •scribed In referees • •d •, 
Table • 

Results L.A. Incinerator Tests 

Destruction Efficiency* 

Ueder Stated Conditions 

DestructiDn •fficiency vs. Tem•ara%ure 

Nedian 3rd 

Quartile 

13D•.- 13•D 32 93.0 96.4 98.0 

1385 1420 4• 94.0 96.0 98.6 

1425 1475 49 91.5 95.0 97.4 

1480 and gre,_-_.:- 2:• 9•.5 96.5 98.6 

Is• Median 3rd 

Quartile Quartile 

D 399 16 85.t 

•OD 7)• 21 91.0 

800 !199 1• 90.0 

1200 1599 16 86.0 

1600 1999 9 •3.0 

2OOO 2399 II 91.0 

2400 3199 12 95.9 

3200 3999 9 97.0 

4D20 •999 13 95.5 

50• 5999 • 9•.9 

600• 699• 8 96.0 

7000 or more I• 98.2 

90.8 96.0 

93.3 97-. 2 

92.5 94.7 

92.9 97.9 

94.5 96.0 

95.5 97.3 

98.4 

97.8 99.0 

98.4 99.2 

97.5 98.1 

97.5 9•.4 

98.7 99.5 

efficiency as •eight.percent carbon. 

•e •ue•t•es a•e used ra•her tha•.ave•ages and standard deviations •Ju•-Tm•••h•-Ch-•-C,=-T•-•ere--•-•Ie-d. 
Table 5 

Resu]t Comparison 

Lab incinerator vs. Ro,hm & Haas Incinerator* 

Roh• & Haas Lab 

]nciT•erator Incinerator 

Inlet Outlet Inlet Outlet 

C.o•,,;pound (•bs/hr) (l•s/hr) (grams/sec) {9rams/sec) 

pro•ane 900 150 9.0 .08 

propylene iBOO**, 150"* 18.0 .70 

ethane IO 375 .I .50 

ethylene 33 19O .3 .43 

ZT•D 8•5 27.4 1.71 

% VOC Destructic• 6•.a% 93.8 

*Table shows t•a :eszru:tion efficiency on the four listed compounds for the 

Ro•f•. & Haas (R•) field and U•ion Carbide (UC) lab incinerators. The R&H results 

are measured; the •C res•ICs•are calculated. Both sets of results are based on 

•-•25"F combastiom le•er•ture and I second residence time. In addition, the 

UC results are base• on co•plete backmixin• and a four step combustion sequence 

•unsistlag of pr•ane to •ropvleqe *• e ÷W--- -- --•..• •...- 

...: ,¢ne Lo •v 2 =,•G =•.:. ,o--:-• i:•,,,• a•'= •orst case assumptions. 

**Are not actua• values. Actual values are confidential. Calculations with actual 

give similar results. 

•alues 
Table 6 

Results Selected L.A. Incinerator Tests* 

Te•pera t u re ] nl et "* (•ut] et ** 

Test ICc. {°F} Concentration Concentration Destruction 

]lSE 13DO 2300 60 

1400 16DD 83 94.9 

1214 14OD i2DD 23 95.2 

151• 1200 89 92.7 

1215 1400 !500 94 o=•. 9 

ISOO ISOO 170 89.I 

1329 1300 3100 27 99.2 

1325 3700 70 98.1 

1375 3800 120 96.9 

-• 2700 7 99.7 

17•6 1320 7430 83 98.9 

1410 6247 88 98.6 

1509 7370 104 98.6 

1842 ]140 1260 83 93.5. 

1285 1090 60 9•.5 

I•25 1420 109 93,9 

2130 1300 801 3• 93.9 

1375 777 66 89.4 

1495 890 63 90.7 

2235 1400 110/55 97 99.1 

l•Sg 10731 254 97.6 

2359 I•DO 871 90 85.1 

I•50 871 131 72.3 

2624A 1ZOO 4110 60 98.1 

1450 3090 65 9•.• 

2624B 1200 1405 23 9B'.4 

• • 18_ 

* artla, •s%m 9 o tests w 7re •n¢Iner•tor te,apera:ure was Jncrease• 

chan•e Or a •C•Se in Y• 

nO 
Table ? 

Cost Comparison Incremental 

Capital Cost and Fuel Savings 

with Heat Recovery* 

!ncineret•rs not Requirino Supplem•ntal Air** 

Inlet Flow Recuperative (SCFM) H_--at Recovery 

30 

70 

1000 

Incr. •ncr. 

Capital Fuel 

S15,600 Sll ,500 

$6,600 $7,500 

$ID,800 $7,500 

2O00 

Incr. Incr. 

Capital Fuel 

$I$,600 $23,000 

$9,900 $15,000 

$13,500 $15,000 

3000 

Incr. Incr. 

Capi tel Fuel 

30 $22,5•0 .c3•,500 

50 $12,000 $22,500 

?f), $18,000 $22,500 

Incinerators R•ntal Air 

Hea% Recover• 

SO 

7O 

lO000 

Inc•. Incr. 

Capital Fuel 

$35,000 $I15,000 

S29,000 $75,000 

$59,000 $75,000 

700 5C90 

Incr. Incr. Incr. incr. 

Capital Fuel Capital Fuel 

$.13,000 $27,000 $27,000 $178,000 

SS,DO0 $I0,000 $12,0OO $84,000 

$2,000 S9,000 $13,000 $77,000 

Dc..l•ar figures are the incremental annualized capital cos:s and inc;ement•l 

a,mu•l fue• cos% savin• for increasing the heat recovery from the previous 

lewel to t•e li$:ed level. For example, She figure• on the 50% line are the 

cos:s end savings of going f•o• 30% to 50% heat recovery, and on the 30% line, 

of going fro• no heat recover• t• •O% recover•. Costs are based on an 

incinerator operating at l•OO°F and .75 seconds residence time. 70• recuperative 

heat recovery corresponds So an exit gas t•perature of approximately 550OF. 

Cos$$ based on Reference 10. 
Table 8 

Cost C•mparison Incremen•al 

Coszs of Combustion 

Temperature Inzrease 

•mcinerators Requirine S:•mlemental Air* 

Capital Incr. Anmu•lized Incr. 

Flov: Cosl Capital Percent Cosz Annuel Percent 

(scfm" 1400OF ** tc 160•°F increase 140•F ***. to 160O°F ]ncrease 

7 O0 32 S 38 1% 137 i 1 

5900 5•3 97 17% 288 28 10% 

25',}00 •-",,..- 438 24% 965 127 13% 

50000 2•73 855 28% 1741 248 14% 

inci•erator• •t Read!rime S:;D•lemental Air 

IOUO 3Z• 36 II% 139 I0 7% 

•.• 7C-• 135 19• 363 40 I0% 

P _D•, 13!0 330 25• 728 96 13% 

• •,mne•-• ousanc• o o ars 

*÷T;•e zc•iLai cc•t c•l•mm •ho:.• the tmt•l inst•iled capital for an incinermtor om•ratin 9 

c;. ;s•,:.;;, .V• :•ccm:• rasi•,ae Li,,•e, recupe)'a•ive recovery wizn an exi: gas.temperature 

of 510°F, and Znm lis%em flow. Th• next column shows the extra capital for a similar 

incinerator operati.n§ at 16OOmF. The fourth column shows the percent increase in 

capital cost from 14DDOF to 16OO°F. 

***The annualized cost column shows the total annual cost !depreciation, inte•e•t, taxes, 

utilities and maintenance) for 14000F,'.75 seconds, 51D•F exit tmmperature a;•d the. 

listed flow. The next columm s•ows the incremental annualized cost for a similar 

incineKator at 16DD•F. The seventh column shows the percent increase in annualized 

cost from,. 14OC•F to I•OO•F. 
Appendix A 

Mixing is a key concept in incinerator efficiency. Th•s, a discussion 

of incinerator efficiency will likely rely heavily on this concept. 

However, Mixing is also a complex concept. Thus, discussions of efficiency 

can beco• burdened with.%echnizal explanations of mixing. To handle 

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

leaves detailed explanation of 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 •ixin 9. 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.te.•.•erature and 

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

cause. 

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 

•ir. The c•bustion gases from burning supplemental fuel provide the 

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

provides oxygen to combust the supplemental fuel and VOC's. 

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 smaI1 fraction of 

the incinerator residence time. 

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

the incirerator intact. The turbulence in the incinerator fai•s to break 

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

level :o occur. Poor mixing also results if this intermingling occurS too 

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

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

R.T., and complete combustion may not occur. Fine11• poor lrixlng results 

if only one of the t•o required .streams, i.,e, combustion gas or supplemental 

air, is proper•y dispersed. For example, the waste gas may be proper1• 

intermingled wi•h ¢•b•stion gases, but the supplemental air f]ow ma• be 

stratified. •he re•It wou•d be incoe•lete combustion. 

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

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

to broad arrows represen%ing the macroscopic currents. 
-2- 

Certain flow re_times have been labelled. In plu_o flow, inlet .oases 

remain within fixe• vertical "slices" that travel directly fro• inlet to 

outlet with no backflo•'. ]n complete backmixing, the opposite occurs. 

inlet .Gases are rapidly spread throughout the incinerator and significant 

backf]o• occurs. DtheF flow re_eimes are composites of these. In two 

sZa_o• bacK•ixin;, the incinerator operates like two units in series, 

vo'i:h each undergoing com,.late backm, ixin•. Clearly, ac:ual flow patterns 

rare•y ccrrespond to these idealized types, but •hese types can serve as 

•ppr•xi•tions. 

Flow regim• is related to bo:h mixing and efficiency. Specifically, 

the f•ow reEimes most favorable to high efficiency are the least favorable 

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

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

achieve goo• •ixing and still maintain plug flow, the gases in each 

vertical "slice" •st completely mix with each other while remaining 

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

create. Es the gases •ix vertically they also tend to mix horizontally, 

resul%in• in a flow patte•, closer to complete backmixing. Thus, providin• 

good •ix!ng inherently creates flow patterns less advantageous to high 

efficiencies. 

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

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

designed for optin• •ixing and thus the UC results represent the upper 

li•i• of incinerator efficiency. This upper limit is used in evaluating 

the costs involved in adjusting and desi•ening an incinerator to reach a 

giv• effici•y. Tim closer this giv• efficier•y is to the upper 

li•it, the higher •he 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 •ixing. Thus, since this memo 

is considering efficiencies applicable to all incinerators, a conservative 

assumption of complete backmixingwas required when considering the 

upper limit of efficiency. 

L.A. Data 

The L.A. d•ta surprisingly showed no relation between temperature 

and effic•encj¢. Various factors were analyzed to determine the cause 

for this r•sult. 
In a search for the cause, sampling error and the incinerator 

variables of residence time, inlet concentration and type of compound 

were ruled out. For sampling error to be the cause, the sampling would 

have had to consistently underestimate efficiency in high temperature 

tests and overestimate it in low temperature tests. With over 150 

tests, this is essentially impossible. For the thr•e incinerator variables 

to have been the cause, these variables would need to mask the effect of 

temperature. However, based on the Union Carbide work and kinetic 

theory, these variables only scatter the efficiencies around an average 

determined by temperature. In the UC cases, the effect of te•erature is still seen in the increasing average efficiency. 

The remaining variable is mixing. A plausible explanation of the results is possible if this variable is considered. The reason lies in 

two factors which allow mixing to mask the relation of temperature and efficiency. First, the co•leteness of mixing can drop with te•N)erature. Thus, improper mixing can offset the effect of increasing te•erature. In contrast, the other variables remain the s• as te•erature changes and thus offsetting cannot occur. Second, increases in temperature only increase the efficiency of the we]I-mlxed portion of the waste gas. 

Since this portion contains only part of the •co•usted VOC, and likely the smaller part, the impact of increasing temperature is greatly diluted. In contrast, the other variables cannot "isolate" parts of the waste gas from the affect of te•erature. 
REFERENCES 

I. Predictive Model of Ti•e-Temperature requirements for Thermal Deszruction 

of Dilute Organic Vapers, Kun-chieh Lee, Ja.•es L. Ha•sen, Dennis C. •cCauley, 

U•o• Carbi•e, South Sha:-•es•on, West Virginia. 

2. E•ission Tesz of Acrylic AciC and Eszer •nufacturi• P•ant, Union Carbide, 

T•ft, Louisiana, Draft Report b• Mi•esC Resea:-c•, t•y 1979. 

•. Emission Tes• of Acry]i: Aci• ant Ester M•nufa•turin• Plant, •ohm and Haas, 

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

•. Stationary Source Testin• of a M•leic •hydride Plant at the Denka Ch•ical 

Cor•oration, Houston, Texas, Final Report by Midwest Research Institute. 

•. ;•Dvemt.er 8, }979, •etter, Michael F. Weishaar, Monsantc, St. Louis, 

•4issouri, to Jack •. Farmer, •.$. Environmental Protection Agency, 

Researr• Triang}e Rark, 

6. AuguSt 15, lg79,Let:er, Roger Towe, Pet•o-Tex, Houston, Texas, to 

Jack R. Farmer, U.S. EnvironmenSa} Pro•ec$ion Agency, Research Triangle 

Park, N.C. 

7. •rch •D, lg•D, Le•%er, •eorge F. Martin, PetrooTex, Houston, Texas, 

to Da•i• C. Mascone, •.S. Environmental Protec•io• Agency, Research 

Triangle Park, •.C. •7711. 

•. •anuar}c 17, lg7g, LeSSer, Al•o•zo Wm. Lawrence, Ko•ers, Pt•%sburgfl, 

Pe•.ns•l•nia, %o Don R. •)o•.i•, U.S. EnVironmental Protec%ton A•enc•, 

g. Se$ of. sum•rie• of e•issio• •est$ I}erfo•med b• Los A•eles County personnel 

fram lg70 %o lg7g. 

Knoxville, Tennessee, I)ece•er lg7g. 
UNITED STATES Ei•V•RONME.•.'TAL PROTECTIO• AGENCY 

FR Oft.; 

TO: 

JUL 2 2 1•0 

Tner•a• incinerator Perfo.-•.•nz• for NSPS, Addendur• 

D•-vi d C. V•scone•'• 

Chemical V•nufacturin.e Section 

Jack R. Farmer, Chief 

Chemicals and Petrole=•. Branch, 

After reviewin• the recent memo on incinerator perfo,-mance, (Thermal Incin•_rato• Perzformance for RSPS, June II, I•0, DCM, to 

J•rme.•d• s--6•r•-•--ar-• where further eiscussion was 

desired. These areas were as •fo]lows: 

continuous compliance of thermal incinerators 

the impact of compound on efficiency the impact of inle• concentration o• cos: effec•ivesness and 

efficiency 

These three areas •re discussed below preceeded by a s•ar• of the 

conclusions. 

Concl us ion......_._._•s 

In the absence of a demonstrated continuous V0C monitor for •hermal 

incinerators, CPB is investigating alternate meth•s. After study of. 

the cost and effective:•ss of several such methods, the followlng should 

be considered: continuous temperature and flow monitorin• and hi-annual 

compliance testing and inspection/•tntenance. For example, in monitoring :emperature and flow, a company could be required to run the incinerator 

be•e. *•0"F of the temperature, and between +20 percent and -50 percent 

of the fTow, measured during the performance test. 

I)e•tled analysis shows that type of compound does aff=ct incinerator efficiency. However, •ue to the co•lexit• of the relationship, no 

att•,mpts were made in the •une 11 m•mo to d•aw fi•-1•Ut•L•d efficlenc3' conc1•sion$ relating different efficiencies to different compounds at 

different t•rai•reS. Rather, a more ¢onversative approach was taken •.which. the efficiency conclusions were based on the most dlfficu•t co•=ounds to co.bust. These conclusions, based on such a worst case 
-2- 

Detailed analysi• also shows that inlet concentration affects 

incinerator efficiency. However, unlike •ype of compound, statistical 

study of the relationship between inlet concentration and efficiency was 

possible. Based on this study, the co•clusions in the June II incinerator 

memo are expressed in both ppmv and percent reduction. This dual format 

accounts for the effect of inlet conce•zration. 

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 is to change the amount of VOC controlled. Over a typical 

range of inlet concentrations •..•. lO,O00 to 500 ppm) a,.• for an 

incinerator with 70 percent recuperative beat 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 CPB goal is continuous monitoring of ai• 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 r•nitoring methods, s•ch as measuring firebox temperature, to indicate incinerator performance. 

To develop alternate monitoring methods, two goals were considered. 

First, these alternate, methods should detect a11 or most cases of poo r 

incinerator performance. Second, t•e methods should have reasonable 

costs and impose reasonable recordkeeping requirements. 

To meet these goals, the variables that affected incinerator performance 

were anaIvx•d. The•e variables are ten•oerature, mixing, type of co•ound, inlet co. c ;ration, residence time, and flow regime. Of these variables, the last •:,•ee were judged of little concern when considering continuous •w)nitoring. These three variables are essentially set after incinerator 

construction and adjusl•ent and/or have only small impact on incinerator perfomance. The three remaining variableswere then analyzed in more 

detail to define their impact on perfomance and the ability to monitor 

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

•he previous incinerator memo. Even with good mixing, the Union Carbide lab da•a and kinetic •eory show that lower temperatures cause significant decreases in efficiency. In addition, the L.A. data indicate that increasleg i•emperature cae also adversely affect eff•.ciency, apparently by changing mlxin•. In term of cost, temperature monitors are inexpensive, costing less than $5000 insta]le• with strip c•arts, and are ea•il• and cheaply operated. Given the ]aroe e•fect of temperature on efficiency 

• 

and the ]•w cost of ten•rature •onitors, this variable is clearly an 

•-1:•"ameter•o-•mnil:or;-. 
• an example, • spec•.•c re•ui•,ent could be that •n incinerator 

cannot be operatic for • than • h•u• at an evera• fi•box te•ratu-• B)ove 5•'F over, or under 5D•F •i•'. the aver•) •r•ture •co•ed •ur!n• perfo•nce testing, if an o•rating ran• g•ater than 10O'F is •esi•d, • co•anj' coulC perfo• perfo•nce tes• •t • than one te•er•tu•. The •r• .hour ti• •eriod would co-festal to t• •riod •qui•d for ir, tegr•tec )•g sa•ling in a typical •rfo•nce test. This would •ke the averaging period for te•erature •ni•ring si•lar to that of the •rfo•nce te•t. Fin•l!y. the c•an), coul• • •qui•d tc install, operate, and c•ICbr•te the •nitor accor0ir, g to •nufac•r's s•cifications. These •pe:•fic•)ions general i) cover p•per plac•nt of ihe •nitor. 

The r•ext variable studied was mixing. Tl• •st likely it• to affect •ixing. given a constant •rature and an already constructed incinerator, woulC • fi•. No dl•ct field • is •vail•le on •e 

e•fect of flo•, on •ixing efficie•y. H•ver, bas• on engin•ring judgmr•t, increasing fl•, •4)' lead to "sNmci•uiting." •m tN increased kinetic ener•, of 6,igh(r fl• stream causes was• gas to jet through the incimrator un•ixed. •cmased •" r¢y lead to t• opposite. •'hem i•er fl•' ra•s result in insufficlent kirtle mer• for coml•te • i•:ing. A• •'Ith temeratum, • mnltom am Imxpensive and easily o•rated. •iven the p•tential Imact of •m-on efficiency, and the lo•" cost of fl• mnitom, fl•, rate i% also an •ffectlve •ramter to •or,! tot. 

A• an exile, a s;)eclfic requirement coulo be that an incinerator cannot be o;•r•ted for •re •an three hours •t an avera) flow less tY•n 

•' 

5D ;>ercent or greater •han ll0 l•.'cent of tl• aver• wast• gas recor•d du•ng a •rfor•an:e lest. )l• Nnmisslble range •uld be intentiOn611y b•ad d• to • lack cf field • • the (matt of flo. on •ixing •nd efflclency. The .p•r •stricti• •Id be tighter than the l•er $ince increase 61• not only •y adve.ely affect mlxln) but decreases rest•nce ti•. •y adve•e effec• of •c•ased • •y • offset by the tnc•aseO •st•nce ti•. T• above discussion for temeratu• on ,'i•r, in; t• o•r•ting ran•, the thr• hour tim ltmtt, and Installation, o•ration •:-J c•tibr•tion of the •nitor •ould hold for this • •nftortn e•le. 

The final variable ar•l)'.-ed •S type of c•und. For most incinerator • ;•llc•tlons, the c•d• in the •s• •s • se• by •he p•cess to •ch the incilrator is attac•. Yhus, :yR of C•und iS of no 

conce•. •ver, ce•in applicatl•s •y have differing c•un0s in 

an •K base. a.d •en swit• to a ;olvent .ith a toluene base. •K Is oxidizeU ea;l•r t•n •lue•. and •us an incinerator which achieves 
-4- 

The judgement on this it• is that no general monitoring requirement 

on type of compound can be specified. Most cases will have the waste 

gas compounds set by the process. In those that do not, considerable 

difficulty is envisioned in defining: in a general wiy, when the waste 

gas compounds have changed enough to require additional compliance 

tests. For example, dif•erentiatin• be•ween solvent for•ulations would 

be difficult. The same generic name ef solvent may s.how 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 temerature, flow and type of compound held 

constant. Data on this issue is shown in Table I. The top pa• of the 

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

in different years. The bottom part lists possible incinerator malfunctions 

that could affect performance, without changing temperature and flow. 

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

are judged to have fairly stable performance over time. The L.A. units 

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

these units changed less than two percentage points over several years, 

except one case. In addition, the lid.ted malfunctions are judged to 

occur infrequently. This is based on several factors. First, these 

talfunctions involve non-moving parts subject to little wear. Also, the 

typical was¢e gases are not highly corrosive and the typical incinerator 

fuels, nature1 gas and fue] oil, have low sulfur and ash content. 

Finally, even t•ough Incinerators undergo wide temperature s•ngs, 

incinerator components are designed to withstand these changes, given 

proper coollng and heating of the unit.. 

The above conclt,sion should not be overstated. Though fairly stable, all four L.A. data sets show so• drop in performance over time. 

And though improbable, incinerator malfunctions are not impossible. Thus, the conclusion fro• the data is not that no additional requirements 

are needed over temperature and flow monitoring. Rather, the conclusion iS that the costs and recordkeeping of additional ,onttortng requirements must be carefully balanced against emissions potentially prevented by them. 

After l•is balance was studied, t•o additional requirements were 

considered. These are hi-annual perfomance l•sttng and hi-annual inspection and mintenaece (I & M) for incinerators. The performnc• testing (uld follow the method $l•Ifled in the standard. The I &M 

would involve visual Inspecti• f•r item $•h as corr•)sion aed firebox 

deterioration, calibration and testing of control instrumentation, and 

so on. Suc• I & M could rest likely be performed at the s• time as a 

process tur•ar•n•. 
-5- 

These two additional monitoring nethods would effectively detect 

drops it. incinerator performance no: detected by temperature and flow 

moni%orin.c. Perfor•.•nce te_•tin.o is the m•st direct m•ar.s of detecting 

•oor efficiency. The I & M will catch drops in performance by spotting 

equipment failures or impendin• failures •hat could lead to poor performance. 

The ] & • has the added advantag=, that i .mpending failures which could 

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

•or compliance testing and • & M is based on the rate at which incinerator 

per,•o•ance is likely to deteriorate. The two year period for & V, also 

correspon•.s to the typical •in• betweer, process turnaround.•. Thus, with a 

bi-annua% .• •; M %he incinerator ! & V. could be performed at the san• time. 

•s process equip•nt I & M, and it would not be necessary to shut down 

the [.-ocess just •o check the incinerator. Finally, the timin@ of the 

performance test and the I & Y, are no% linkea. They can be done together in any order or apart. 

Type of Coln•und One factor which affects incinerator efficiency is type of co•)ound. The June 11 memo on incinerator efficiency excludes 

this factor fro• its conclusions, but discusses only briefly •he reasons 

for this exclusion. This section discusses the i•act of this factor on 

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

In terms cf the in•ct of c•und on efficiency, the available 

incinerator daT• d•es show a moderate i•act. The Union Carbide lab 

¢ata demonstrates this most clearly. In cases w•ere different coa•ounds 

were incinerated at the same tea•rature, residence time, and flow 

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

temperatures a•ove ]4OO°F. At lower temperatures, the efficienc• variations increased up to 20 and 30 percentage points. 

However, as a practical matter, including'co•ound as a factor 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 co•ustion Thus, analysis of the relation between 

efficiency and coe•)ound was limited. Second, even if a relationship could be devised, it would be complex and difficult to apply..The relationship would likely involve kinetic rate constants, autoignition temperatures, factors for •lecularconfiguration and structural groups 

an• similar variables. 

To avoid these di•flcu]ties, an alternative approach was taken. No 

initial a•te•ts were •de at drawin• a fine-iyJned efficiency conclusion showleg differin• efficiencle• a• diff•rin 9 te•eratures for different 

coe•unds. P•the•, a conservative approach of choosing a simple set of 

in{i•al•r •r•i•ioes and efficienciesbased on the .most difficul• c•,upounds to coe#)ust was pursued. This approach proved successful. 
-6- 

Several factors aided in the success of this approach. First, the 

available test data covered a wide range of cou•ounds. The confounds on 

which test data were available included C l to C 5 alkanes and olefins, 

aromatics such as benzene, toluene, and xylene, oxygenated co•ounds 

such as I•£K and isopropanol, nitrogen containing species such as acrylonitr•l• 

and ethylamines and chlorinated compounds such as vinyl chloride. With 

such a range of con•unds and the consideration of kinetics, it was concluded 

that worst case c(xnpounds had been taken into account. The second 

factor was the discovery that increasing combustion te•erature resulted 

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

choosing a higher ten•erature to cover the worst cases did not make 

incinerators unaffordable or too energy intensive. 

Inlet Concentration A second factor which affects efficiency is 

inlet concentraton. Unlike type of co•und, an allowance for this 

factor was include• in the efficiency conclusions. Specifically, these 

conclusions included not only an e,•ficiency of g8 percent but a m4nimum 

exit concentration of 20 ppmv by co•ound, l•us, as inlet concentration 

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

with a 5DO ppmv inlet concentration for a waste gas containing oxygen, 

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

in',6t, a 92 percent efficiency. This section explains in more detail 

the reasons for this allowance for inlet concentration. 

The test results fre• L.A. County form the mjor basis for this 

allowance. These results show a strong trend w ._•re lower inlet concentration 

results in lower efficiency. For exan•le, for Inlet concentrations less 

t•n 16DO ppmv as carbon, the median L.A. efficiency was approximately g2 percent. For inlet concentrations between 1600 and 2400, the median 

L.A. efficiency was approximately g• percent. For inlet concentratlor.s 

above 2400, the median efficiency, was approximately g7 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, availab•e21itera•e indicates 

that co•bustion follows complexreaction mechanisms. In cases, these 

•echar,;sms can be fit to a first order model. However, as a general rule, these mechanisms, which invol:e rhain reactions, free radicals and 

multiple pathways, cannot be reduced to first order •w)dels. 

The June II, Ig$O, incinerator memo concluded that the L.A. incinerators 

did not all achieve proper mixing. T;•.is i•roper mixing may have caused 

or influenced the •lction between efficiency and inlet concentration in 

the L.A. data. Ifthis i$ the case, then an allowance for inlet concentration 

may permlt lower efficiencies than are actually achievable in incinerators 

with proper mixing. However, the possible effect of poor mixincj 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. 
-7- 

Inlet concentration also impacts cost effectiveness, i.e. costs per 

unit weight VOC controlled. The precise impact depends on molecular 

weight, the size of the incinerator an• the ratio of was:e gas energy 

content to VOC. Figure l 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 is not a m•jor factor in 

cost effectiveness. Incinerator size and the amo•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 contration fro•, 50D0 to 5OD ppmv increases the cost 

effectiveness only Z0 percent. The fact t•t only one-tenth the benzene 

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

lO00percent. Ar, d decreasin§ the stream s•ze to 1000 SCFI• increases the 

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

lower ppmv is only a minor factor. 

Rolke, R.k'., at. al. Afterburner System Stud/, U.S. Environmental 

Protection Agency, Report S-14121, Shel• l)evelo•ment Company, 1971. 

2Barnes, R.H., at. al Chemical Aspects of Afterburner S•tems, IERL Repor• 

U.S. Environmental Protection Agency, EPA-6OO/7-7g-O96. l•telle Colm•bus 

Laboratories, April 1979. 
ICe 

Parz A L.A. Test Data* 

Inlet. Outlet 

Test No. Dote (ppmv carbon) 

% VOC FIow(SCFM)/ 

Destruction Temp. (OF) 

& •icht 1754 I0-30-73 •¢3 33 

zurino 2442 7- 7---•6 1030 9• 

2443 B-lO-78 716 94 

Znc. 2226 5-12-75 6020 52 

2402 2-17-76 5860 71 

onal Can 1430 6-I0-70 4900 31 

1746 •-21-74 7370 104 

Can 1451 6-I0-70 3500 22 

17• 3-21-74 6247 82 

7370 79 

92.5 3270/13(•) 

91.4 2020/130D 

87.3 2050/ 

99.0 1210/1260 

ga.• 4150/1375 

99•4 2520/1500 

98.6 19g0/1500 

99.4 4620/1460 

98.0 4660/1420 

98.0 4650/1525 

Part 5 Possible Incinerator F•Ifunctions** 

function Cause Possible Effect on VOC Control 

Firebrick Deterioration 

Insulazion Loss fro• 

Incinerator Exterior 

Improper heating & c•ling 

,.of incinerator during 

start-up & shut•; 

flrebox t•erature too 

high 

General •eathering & 

corrosion fro• rain, cold, 

incinerator start-up & 

shutdown & so on 

Deteriorated wall allow•.local 

heat loss resulting in cool spots 

in firebox, and thus potentially.- 

lower destruction efficiency in 

those spots 

Same:as previous; insulation loss 

leads to local heat loss & cool s•: 

in the incinerator 

Corrosion of ducts, 

baffles & other 

exposed n•tal 

Plugging cf Burners 

Ash, acids, salts, etc. 

in fuel or waste gas 

Ash & carbon buiJd-up 

Severe corrosion of metal parts 

affects the gas flow patterns 

through and around them, potentiaT 

affecting mixing & thus efficient)- 

A plugged or partially plugged bu• 

affects the flow patterns& 

temperature profiles in the fireb• 

potentially lowering destruction 

efficiency 

Breaking of Recuperative •enerel corrosion; t•er- Inlet waste gas leaks into the out7 

Heat Exchanger Seals ature warping fro• hot spots flue gas without passing through •L•_ej•J•je•• •J•_• r•oL 

heating & c•ling during 

start-up & Shut• 

lnc s were testeo in more• one year. 

list• •lfunc¢i•s include •ly those •ich •uld likely not affect t•erature at a 

li•le [mint flr•ox te•erature •itor or inlet/outlet flow. 

Figure l Notes and Explanation 

Figure shows the cost effectiveness of thermal incinerators by inlet 

c•centration and waste gas flow. The cost effectiveness is in hundred dollars 

per 2000 pound ton; inlet concentration is ppmv by compound; and the flow rate 

is in SCFK. The costs in the figure assume a waste gas deficient in air, and 

a Compound with a n•lecular weiQhC of 80 and a heat of combustion of.15,000 BTU/Ib VOC. 

The thermal incinerator operates at 1600OF 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 co•pounds with different molecular 

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

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

would read 2DOO, 4000, and 6000. For cases where the waste gas contains sufficient 

oxygen for coW,simon, the cost effectiveness should be decreased'by the following • 

percentages: 

lO00 SCFM 

2500 SCFM 14% 

5000 SCFM 21• 

lO000 SCFM 26% 

25000 SCFM 30% 

This adjustment accounts for the sr, aller size and lower fuel requirements of these 

cases. Finally, for cases where the con•ustion value of the stream per pound of 

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

assume 30,000 BTU/Ib 

for ppmv <500 No adjustn•nt 

for ppmv between I000 SCFM 5% 

•00 & 3000 2500 SCF• 10% 

5000 SCFM 15% 

I0000 SCF• 20g 

25000.SCFM 25g 

These adjustments 

for ppmv >3000 No adjustment 

This adjustment accounts for the l.ow•r fu•l use at higher BTU/Ib levels.