OAR Box 1870 

Prepped by Ollie Stewart 

Document Number: 

13) ll-A-18 

Docket Number: 

A-90-19 

Printed 11/28/2008 7:05:04 AM Sheet 13 of 67 

P.1 
P.2 

i ' * > A-90-19 

ll-A-18 

bHA-450/3-80-026 

Organic Chemical Manufacturing 

Volume 4: Combustion 

Control Devices 5jr

i_iU_j_li 

EPA AIR DOCKET 

Emission Standards and Engineering Division 

U.S. ENVIRONMENTAL PROTECTION AGENCY 

Office of Air, Noise, and Radiation 

Office of Air Quality Planning and Standards 

Research Triangle Park. North Carolina 27711 

December 1980 
P.3 

ill 

This report was furnished to the Environmental Protection Agency by IT Enviroscience, 9041 Executive Park Drive, Knoxville, Tennessee 37923, in fulfillment 

of Contract No. 68-02-2577. The contents of this report are reproduced herein 

as received from IT Enviroscience. The opinions, findings, and conclusions 

expressed are those of the authors and not necessarily those of the Environmental Protection Agency. Mention of trade names or commercial products is not 

intended to constitute endorsement or recommendation for use. Copies of this 

report are available, as supplies permit, through the Library Services Office 

(MD-35), U.S. Environmental Protection Agency, Research Triangle Park, North 

Carolina 27711, or from National Technical Information Services, 5285 Port 

Royal Road, Springfield, Virginia 22161. 

D124R 
P.4 

1-i 

REPORT 1 

CONTROL DEVICE EVALUATION 

THERMAL OXIDATION 

J. W. Blackburn 

IT Enviroscience 

9041 Executive Park Drive 

Knoxville, Tennessee 37923 

Prepared for 

Emission Standards and Engineering Division 

Office of Air Quality Planning and Standards 

ENVIRONMENTAL PROTECTION AGENCY 

Research Triangle Park, North Carolina 

< 

July 1980 

D75G 
P.5 

III-l 

III. BASIS FOR THERMAL OXIDIZER DESIGN 

After the design considerations described in the preceding section were evaluated, 

those sensitive design variables that would have an effect on cost and energy 

were identified and are described below. 

a 

AEFFECT OF SENSITIVE DESIGN VARIABLES ON COST AND ENERGY 

A distinction must be made between those design variables which, if changed by 

a small amount, would cause significant changes in capital annual or energy 

costs. These are called sensitive variables, and the cost curves given later 

in the report generally include them as parameters. Other variables may be 

quite important for an individual system design but have minor effects on economic 

or energy impact conclusions. 

The approach used in this study was to determine the sensitivity of certain 

variables by means of computerized heat and material balance calculations. 

Through this process, estimates of the relationships between the variables and 

eguipment design and operating costs may be derived. Primary variables that 

are a function of the waste gas are the waste gas temperature, pressure, flow 

rate, VOC composition and VOC average molecular weight, VOC carbon, oxygen, and 

hydrogen (and other component) ratios, VOC heats of combustion, and the nitrogen 

(and other inert gases), oxygen, and water contents, and the presence of special 

contaminants (particulates, halogens, high levels of sulfur). 

The waste gas temperature is assumed to be 100°F for the base case, but an increase 

or decrease within reasonable boundaries will have little effect upon the capital 

or operating costs and it is therefore not a significant variable. Sensible 

heat carried by the waste gas is small compared to that required to raise its 

temperature to the combustion conditions. About 3.5 Btu/scf is required to 

increase the temperature of nitrogen from 80°F to 260°F. This compares with 

fuel heat requirements on the order of 60 to 80 Btu/scf to raise the waste gas 

to combustion temperatures. Waste gas temperature differences within this range 

could not change the total heat requirements by more than about 6%. Waste gas 

pressure is assumed to be 1.5 psig. Pressure changes within reasonable limits 

of 1.5 psig also will have no significant effect on capital or operating costs. 
III-2 

Flow rate is a very significant variable for both capital and operating costs. 

The waste gas flows shown in the figures throughout this report are translated 

to scfm of waste gas to the thermal oxidizer. 

Heat content of the waste gas is a significant variable. VOC molar concentration; average molecular weight; carbon, hydrogen, and oxygen ratios; and heats 

of combustion (Btu/lb of VOC) are all expressed in the variable of the heat 

content of the waste gas (Btu/scf). By assessing the heat of combustion of the 

VOC being destroyed and the mole % VOC concentration in the waste gas, the heat 

content can be determined (Btu/scf) as shown by the family of compound lines on 

Fig. III-l. Multicomponent VOC systems may be described when the mole fractions 

of each component are known. The contribution of carbon monoxide to the total 

heat content may also be analyzed in this way. Table III-l gives VOC molar 

heats of combustion.13 

If the actual flue gas composition is needed, a component material balance must 

be performed, for which carbon, hydrogen, and oxygen ratios are required. In 

order to estimate "typical" values for those ratios, 219 organic compounds containing C, H, 0, N, and Cl were surveyed.14 Table III-2 summarizes this information based on groupings of different classes. The VOC component averages of 

68.3% carbon, 11.4% hydrogen, and 20.3% oxygen were used to establish heat value 

plus heat and material balance for this evaluation. Compounds containing chlorii 

or sulfur are not included in the impact assessment of this study but covered 

in the Control Device Evaluation, Thermal Oxidation Supplement (VOC containing 

halogens or sulfur). 

The level of oxygen in the waste gas is important because compounds containing 

high anoints of oxygen lessen the level of combustion air required and reduce 

the total thermal oxidizer flue gas, which affect both capital and operating 

costs. No additional combustion air is required when the oxygen in the flue 

gas exceeds 3 mole %. This leads to a smaller unit and lower capital and operatin 

costs. Although some designers will use various levels of oxygen to determine 

combustion requirements, the value of 3 mole % is based on accepted practice 

and will be constant for all the desigi calculations- in. this evaluation. In 

order to generate a conservative desist and impact analysis;, the waste gas in 

this report is assumed to have no oxygen. MaxiaMi combustion air ia therefore 
III-3 

P.7 

1000.0 

le 

mg 

100.0 

Li. 

o 

co 

m 

i -

z 

UJ 

O 

o 

UJ 

X 

CO 

< 

<_> 

UJ 

r -

co 

< 

1.0 -/-, 

0.1 

_. . I 

1 i i I 

"BENZENE 1,404,000 Btu/LB M0LEI I I I ' 

1,000.000 Btu/LB MOLE 

/ - / ^ y<C^. y^r y 

^—y/^^' 

/ /l//J/>/ 

iv// 7\//// 

I—/ 

I 

25° 

I.LEL 

vyv 

/ / 

X 

4( D% 

LEL 

A 1 

1 ^ 

>^ 

^4C"L^ 

y-^ ^ 

100% 

LEL 

^>-— 

\ 

--— ' 

| | | j 

2,000,000 Btu/_B MOLE" 

l^^^^-p-rr . 

_^2—- ~ 

—-—J"" J—•—7 

1 

-^ETHYLENE 

607,000 Btu/ 

v—pROpvi pivp | | 

882,000 Btu/LB MOLE 

\—730.250 Btu/LB MOLE 

k* " 

_B MOLE 

100,000 Btu/LB MOLE 

^ ^ ^ 

^ - -

6ARBON TETRACHLORIDE: 

67 140 Rtu/I R MOI F 

(PA 

OF 

RAM. 

COM 

ITER 

BUST 

= M0L 

ION C 

AR H 

)F VO 

EAT 

C) 

10.0 — 

4 5 6 7 8 9 10 11 12 13 14 

VOC COMPOSITION (MOLE %) 

Fig. III-l . Relationship Between Waste Gas Heat Content, 

VOC Composition, and VOC Molar Heat of Combustion 
P.8 

t 

III-4 

Table III-l. VOC Molar Heats of Combustion* 

Compound 

Methane 

Ethane 

Hexane 

Benzene 

Toluene 

Ethylene 

Propylene 

Acetylene 

Methanol 

Ethanol 

Acetic acid 

Phenol 

Methyl chloride 

Methylene chloride 

Chloroform 

Carbon tetrachloride 

Ethyl chloride 

Hexachloroethane 

Dichlorobenzene 

Hexachlorobenzene 

Carbon disulfide 

Carbonyl sulfide 

fttiophene 

Methyl amine 

Aniline 

Urea 

Uric acid 

Ammonia 

Nitromethane 

Nitrobenzene 

Trinitrobenzene 

Molecular 

Weight 

16 

30 

86 

78 

92 

28 

42 

26 

32 

46 

60 

94 

50.5 

85 

119.5 

154 

64.5 

237 

111.5 

285 

76 

60 

84 

31 

93 

60 

168 

17 

61 

123 

213 

Gross or High-Heat of Combustion 

(Btu/lb) 

23,900 

22,400 

20,800 

18,000 

18,300 

21,700 

21,000 

21,500 

9,770 

12,800 

6,270 

14,000 

5,850 

2,260 

1,340 

436 

8,840 

835 

8,230 

3,220 

5,840 

3,920 

14,400 

14,700 

15,700 

4,530 

4,930 

8,300 

5,000 

10,800 

5,610 

(Btu/lb-mole) 

382,400 

672,000 

1,788,800 

1,404,000 

1,683,600 

607,600 

882,000 

559,000 

312,600 

588,800 

376,200 

1,316,000 

295,400 

192,100 

160,100 

67,140 

570,200 

197,900 

917,600 

917,700 

443,800 

235,200 

1,209,600 

455,700 

1,460,100 

271,800 

828,200 

141,100 

305,000 

1,328,400 

1,194,900 

*See ref 12. 
P.9 

III-5 

Table III-2. Summary of Organic Compound Components Surveyed 

Class 

Carbon, hydrogen 

compounds only 

Carbon, hydrogen compounds and carbon, 

hydrogen, oxygen 

compounds 

Carbon, hydrogen, and 

chlorine compounds 

only 

Carbon, hydrogen, oxygen, 

and nitrogen compounds 

and carbon, hydrogen,and 

nitrogen compounds 

All compounds 

Low value* 

Mean 

. High value* 

Low value 

Mean 

High value 

Low value 

Mean 

High value 

Low value 

Mean 

High value 

Low value 

Mean 

High value 

C 

79.9 

85.8 

92.3 

27.0 

68.3 

92.3 

7.8 

34.3 

64.0 

26.1 

60.1 

78.5 

7.8 

62.5 

92.3 

Amount (wt 

H 

7.7 

14.2 

20.1 

2.1 

11.4 

20.4 

0 

4.7 

9.8 

3.7 

11.3 

15.4 

0 

10.4 

20.1 

0 

0 

20.3 

7 

0 

3.6 

52.0 

0 

17.3 

20.1 

%) 

N 

13.0 

25.0 

60.8 

0 

3.9 

60.8 

Cl 

31.5 

60.6 

92.2 

0 

5.9 

92.2 

*Low and high values correspond to the compound with the lowest and highest 

percentage of each element (e.g., carbon). Different .compounds apply to 

different elements; therefore the values shown will not be additive. 
P.10 

4-i 

REPORT 4 

CONTROL DEVICE EVALUATION 

FLARES AND THE USE OF EMISSIONS AS FUELS 

V. Kalcevic 

IT Enviroscience 

9041 Executive Park Drive 

Knoxville, Tennessee 37923 

Prepared for 

Emission Standards and Engineering Division 

Office of Air Quality Planning and Standards 

ENVIRONMENTAL PROTECTION AGENCY 

Research Triangle Park, North Carolina 

February 1981 
II-3 

150 Mm may generate a spray of burning chemicals that could reach ground level 

and present a safety hazard. A water seal is usually located between the disentrainment drum and the flare stack to prevent flashbacks into the system. 

Other devices, such as flame arresters and actuated check valves, may sometimes 

replace a water seal or be used in conjunction with it. 

For safety reasons a stack is used to elevate the flare. The flare must be 

located so that it does not present a hazard to surrounding personnel and 

facilities; therefore the usual choice is to elevate it. The height is determined by designing for a maximum ground-level heat radiation and possibly also 

for plume dispersion in case of emission ignition failure. A stack seal is 

normally used just below the flare tip to impede the incursion of air back into 

the flare system, which could create an explosion potential. The use of a seal 

reduces the operating purge-gas requirements. 

The burner tip is designed to give an environmentally acceptable combustion of 

the flare gas over the flare system's capacity range. Consideration is given 

to flame stability, ignition reliability, effective assist-steam injection, 

and, possibly, noise suppression. The burner tips are normally proprietary in 

design. Flame stability can be enhanced by flame holder retention devices 

incorporated in the flare tip inner circumference. With burner tips with 

modern flame holder designs the flame can be stable over a flare-gas exit 

discharge velocity range of 1 to 600 fps.1 Reliable ignition is obtained by 

continuous pilot burners designed for stablility and positioned around the 

outer perimeter of the flare tip. The number of pilot burners required depends 

on flare size and, possibly, on flare gas composition and wind conditions. The 

pilot burners are ignited by an ignition source system, which can be designed 

for either manual or automatic actuation. Effective assist-steam injection to 

promote turbulence and mixing of air into the flare gas flame for more efficient combustion and smoke suppressions is generally accomplished by using 

high-velocity steam jets positioned around the outer perimeter of the flare 

tip. For the larger flares steam can also be injected concentrically into the 

flare tip. For some proprietary designs steam injection includes the aspiration of air along with the steam.