Computational fluid dynamics modeling of laboratory flames and an industrial flare

Figures & data

Table 1. Variables used in the model

Elemental mass balance error (C, H, O and N)	<5%
High-temperature patch (initial ignition)	1800 K
Turbulence intensity (fuel)	5%
Turbulence intensity (crosswind)	10%
Turbulence model	k-epsilon realizable

Table 2. Conditions used for TCEQ flare test cases

TCEQ case number	Propylene, lb/hr	TNG, lb/hr	Nitrogen, lb/hr	LHV, Btu/scf	Air-assist flow rate, lb/hr	Wind speed, mph
A1.1	919	0	0	2,108	149,173	12.7
A2.1	355	0	0	2,125	83,818	12.8
A2.3	352	0	0	2,108	88,791	10.1
A2.4	353	0	0	2,113	148,799	10.0
A2.5	355	0	0	2,124	119,580	13.3
A3.3	181	18.4	701	334	60,121	11.1
A3.6	181	18.8	704	338	47,494	11.9
A4.3	299	30.3	591	563	66,472	10.7
A6.4	130	12.1	221	585	40,584	14.1
A6.5	130	12.1	221	584	56,594	15.5

Figure 1. Geometry used for the full-scale flare validation.

Figure 2. Flat flame burner (McKenna burner).

Table 3. Conditions used for McKenna flame

Fuel composition (mole fractions)
C2H4	O2	Ar
0.175	0.525	0.300
Exit velocity (m/sec)		0.5757
Temperature (K)		300

Table 4. Conditions used to calculate the Reynolds/ Richardson numbers

d (Pore diameter)	1.00E–04	m	McKenna Technical Support
ρ (Mixture density)	0.036	kg/m^3	Aspen Plus Property Set
μ (Mixture viscosity)	1.97E–05	kg/m-sec	Aspen Plus Property Set
v (Gas velocity)	0.5757	m/sec
g	9.81	m/sec^2	Perry’s Handbook

Figure 3. Geometry used for the simulation of McKenna flame.

Figure 4. Experimental setup used at Sandia National Laboratory.

Table 5. Conditions used for Sandia flame

Co-flow conditions
H2	O2	H2O	CH4	N2
0.0001	0.1193	0.1516	0.0003	0.7287
Co-flow velocity		Co-flow temperature
5.4	m/sec	1350	K
		Jet conditions
CH4		O2		N2
0.3300		0.1518		0.5182
Jet velocity		Jet temperature
100	m/sec	320	K

Figure 5. Three-dimensional geometry used to simulate Sandia flame.

Table 6. Comparison of TCEQ measured and simulated DRE (%)

		2013 Simulation
TCEQ case number	TCEQ measurement	DRE (%)	Error (%)
A1.1	98.0%	99.8%	1.8%
A2.1	97.2%	99.4%	2.2%
A2.3	96.1%	99.5%	3.6%
A2.4	93.0%	98.0%	5.3%
A2.5	95.1%	97.6%	2.6%
A3.3	88.1%	91.7%	4.1%
A3.6	90.8%	99.3%	9.4%
A4.3	95.2%	94.2%	−1.1%
A6.4	92.9%	96.7%	4.0%
A6.5	87.9%	97.4%	10.8%
Average error (absolute)			4.50%

Table 7. Comparison of TCEQ measured and simulated CE (%)

		CFD simulation
TCEQ case number	TCEQ measurement	CE (%)	Error (%)
A1.1	96.9%	96.4%	−0.5%
A2.1	95.9%	96.9%	1.1%
A2.3	94.4%	94.1%	−0.4%
A2.4	89.3%	92.4%	3.4%
A2.5	92.6%	93.0%	0.5%
A3.3	85.2%	81.5%	−4.4%
A3.6	88.2%	92.6%	5.0%
A4.3	93.6%	87.3%	−6.7%
A6.4	89.2%	84.2%	−5.7%
A6.5	81.5%	83.9%	2.9%
Average error (absolute)			3.04%

Figure 6. CFD Simulated flare efficiencies vs. TCEQ measured flare efficiencies.

Figure 7. Comparison of TCEQ measurements and experimental results: DRE (%) vs CZHV.

Figure 8. Comparison of TCEQ measurements and experimental results: CE (%) vs CZHV.

Figure 9. Comparison of experimental and simulated temperature profiles of the flat flame burner.

Figure 10. Comparison of experimental and simulated O₂ mole fractions.

Figure 11. Comparison of experimental and simulated C₂H₄ mole fractions.

Figure 12. Comparison of experimental and simulated CO₂ mole fractions.

Figure 13. Comparison of experimental and simulated CO mole fractions.

Figure 14. Comparison of experimental and simulated CH₂O mole fractions.

Figure 15. Comparison of experimental and simulated temperature profiles of the jet flame.

Figure 16. Comparison of experimental and simulated CH₄ mass fractions.

Figure 17. Comparison of experimental and simulated CO₂ mass fractions.

Figure 18. Comparison of experimental and simulated CO mass fractions.

Figure 19. Comparison of experimental and simulated H₂O mass fractions.

Figure 20. Comparison of experimental and simulated OH mass fractions.

Figure 21. Comparison of experimental and simulated NO mass fractions.