Post on 23-May-2020
Biofuel Combustion Characteristics and Flame Sensor Response
Neehad T IslamResearch Engineer
National Oilheat Research Alliance
Co-author(s):Dr. Tom Butcher
John LeveyRyan Kerr
Overview
•Advanced flame sensor response testing at NORA
•Test implemented to analyze cutoff in pumps that operated on biodiesel
•Dissection of pumps to observe wear and tear
•Rigorous combustion testing on biodiesel including emissions analysis
Advanced Flame Sensor Testing: Methodology
• CAD cell connected to voltage source
• DAQ system collects voltage data every 100ms to show flame behavior
• Pumps from field tested: 12 that ran B20 at least ~10 years, 7 on No. 2 for same time
• Run in cold-start and steady state to analyze transient start and cutoff responses
Simple Circuit for CAD Cell Testing
Notable Observation
180
220
260
300
340
380
420
0 0.4 0.8 1.2 1.6 2
CA
D C
ell R
esis
tan
ce (Ω
)
Time (s)
Solenoid No Solenoid
Repeatability of the Trend
180
220
260
300
340
380
420
0 0.4 0.8 1.2 1.6 2
CA
D C
ell
Re
sist
ance
(Ω
)
Time (s)
230
250
270
290
310
330
350
370
390
410
0 0.4 0.8 1.2 1.6 2
CA
D C
ell
Re
sist
ance
(Ω
)
Time (s)No. 2 B20
*Both pumps do not have solenoid valves
Cutoff Comparison
Examination of Parts
• Each pump was dissected after testing• Pictures of parts taken for comparison• Piston heads below are examples
Never exposed to bio
Ran B20 ~ 10 years
Piston Head – Nominal B0
Piston Head – Nominal B20
Pump Gear– Nominal B0
Pump Gear– Nominal B20
Pump Face– Nominal B0
Pump Face – Nominal B20
Pump Strainer – Nominal B0
Pump Strainer – Nominal B20
Biodiesel Combustion Testing
•Combustion testing on biodiesel with varying viscosities
•Baseline No. 2 oil test for comparison
•Varying excess air – CO2 sweep from ~9-10% to ~15%
•Emissions characteristics for CO2, CO and NOx and SMOKE
•CAD Cell Resistance measured over 10 seconds and averaged
•Graphs made with CO2 as independent variable
CO2 and Excess Air Relationship
6
7
8
9
10
11
12
13
14
15
16
0 20 40 60 80 100
Flu
e ga
s C
O2
(%
)
Excess Air (%)
B0 B20 B50 B100
B20 Comparison: Carbon Monoxide
0
150
300
450
600
750
900
9.5 10.5 11.5 12.5 13.5 14.5 15.5
CO
(p
pm
)
CO2 (%)
No. 2 High Visc B20 Low Visc B20
B20 Comparison: CAD Cell Resistance
250
350
450
550
650
750
850
9.5 10.5 11.5 12.5 13.5 14.5 15.5
CA
D C
ell
Re
sist
ance
(Ω
)
CO2 (%)
No. 2 High Visc B20 Low Visc B20
B20 Comparison: Nitrogen Oxides
50
60
70
80
90
100
110
9.5 10.5 11.5 12.5 13.5 14.5 15.5
NO
x (p
pm
)
CO2 (%)
No. 2 High Visc B20 Low Visc B20
B20 Comparison: SMOKE
0
1
2
3
4
5
6
7
8
9
13.5 13.8 14.1 14.4 14.7 15 15.3
SMO
KE
CO2 (%)
No. 2 High Visc B20 Low Visc B20
What’s the Big Deal?
•Advanced flame sensor testing analyzing pump cutoff shows that operation of pumps with B20 does not hinder performance
•Wear and tear of pumps operating on B20 are essentially the same as those on No. 2 oil
• Combustion performance of B20 means seamless transition from No. 2 oil