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Flare Process 335

Table 3
Comparison of Calculated Values and Values Supplied by the Permit Application
for Flares
Calculated value
System parameters (example Case) a Reported value
Appropriate continuous monitoring system Yes —
Emission stream heating value, h 180 Btu/scf —
e
Supplementary fuel flow rate, Q 6200 scfm —
f
Flare gas exit velocity, U 40 ft/s —
flg
Flare gas flow rate, Q 36200 scfm —
flg
Steam flow rate, Q 1140 lb/min —
s
a Based on emission stream 3.

4. MANAGEMENT
4.1. Data Required for Permit Application

The data necessary to perform the calculations consist of HAP emission stream
characteristics previously compiled on the HAP Emission Stream Data Form (Table
1), flare dimensions, and the required HAP control as determined by the applicable
regulations.
In the case of a permit review, the data outlined below should be supplied by the
applicant. The calculations in this section would then be used to check the appli-
cant’s values. Flare system variables at standard conditions (77°F, 1 atm) should include
the following:
Flare tip diameter, D (in.)
tip
Expected emission stream flow rate, Q (scfm)
e
Emission stream heat content, h (Btu/scf)
e
Temperature of emission stream, T (°F)
e
Mean molecular weight of the emission stream, MW (lb/lb-mol)
e
Steam flow rate, Q (lb/min)
s
Flare gas exit velocity, U (ft/s)
flg
Supplementary fuel flow rate, Q (scfm)
f
Supplementary fuel heat content, h (Btu/scf)
f
Temperature of flare gas, T (ºF)
flg
Flare gas flow rate, Q (scfm)
flg
Flare gas heat content, h (Btu/scf)
flg
4.2. Evaluation of Permit Application
Compare the results from the calculated and reported values using Table 3. If the cal-
culated values of Q , U , Q , and Q are different from the reported values for these
f flg flg s
variables, the differences may be the result of assumptions (e.g., steam to flare gas
ratios) involved in the calculations. In such a case, the reviewer may wish to discuss the
details of the proposed system with the permit applicant.
If the calculated values agree with the reported values, then the operation of the pro-
posed flare system may be considered appropriate based on the assumptions made in