Transcript
Impact of hydrogen admixture to natural gas on installed gas appliances By: Dr. Petra Nitschke-Kowsky, E.ON Ruhrgas Date: 7th June 2012 Venue: WOC 5
Overview Global Target Hydrogen admixture is an important option for greening natural gas Technical questions on the whole chain of transport, distribution and utilization are to be solved. Specific Task: Investigation of the behavior of gas appliances operated with hydrogen admixture to Natural Gas • Characteristics of Hydrogen and Mixtures • Theoretical approach • Lab tests of appliances with different burner types • Results and conclusions
Properties of Hydrogen compared to Natural Gas Hydrogen H2
Methane CH4
Ethane C3H6
Natural Gas H (North Sea)
Gross calorific value Hs (MJ/m³)
12,7
39,9
70,3
41,9
Relative Density d
0,07
0,56
1,04
0,63
Wobbe Number Ws MJ/m³
48,3
53,5
68,7
53,0
Air Requirement Lo (m³/m³)
2,4
9,5
16,9
10,1
Maximum Flame Velocity (cm/sec)
346
43
49
43
Gases (0°C/0°C, 1013 mbar)
Characteristic values are important for: Hs: measurement of consumption, billing Ws: load deviation, air ratio, flame stability L0: air ratio, flame stability V: flame stability d: gas composition, flue gas composition
Natural Gas Qualities in Europe pure and with admixture of Hydrogen
wobbe number Ws (MJ/m³)
60 EASEE Gas
58
G260 Erdgas
15%H2
56
5%H2
54 52 50 48 46 44 0.4
0.45
0.5
0.55
0.6
0.65
0.7
0.75
0.8
relative density G260 H LNG
EASEEgas G260neu
H North Sea North Sea + H2
H Mix LNG + H2
H Russia Russia + H2
The Influence of H2-Admixture on Load and Air Ratio
Load:
100%
1,6
90%
1,4
80%
1,2
70%
1,0 30%
0%
10% 20% Content of Hydrogen
W2 Q 2 Q1 W1 air ratio
1,8
Load
110%
Air ratio:
l1 d2 2 1 l2 d1 W1 2 1 W2
The Influence of H2-Admixture on Flame Velocity for different burner types
flame velocity (cm/sec) *)
60
50
40
30
20
air ratio shift 10
0 0.60
0.70
0.80
0.90
1.00
1.10
1.20
1.30
1.40
1.50
1.60
1.70
1.80
air ratio G20
G20+30%H2
*)NATURALHY, ICHS2007, De Vries, Florisson, Tiekstra, KEMA, Groningen, NL
Appliance Tests in the lab of E.ON Ruhrgas
Appliances: 1 atmospheric boilers 2 condensing boilers 2 condensing boilers with SCOT control 1 micro CHP Stirling Control of flame stability safe operation CO emission curve cold ignition test Measurement of
load efficiency NOx emissions
Results of all appliances: Relative Load with increasing concentration of H2
relative load [%]
110%
CB 1, [fl] CB 1, [pl] CB 2, [fl] CB 2, [pl] CB 3 SCOT, [fl] CB 3 SCOT, [pl] CB 4 SCOT [fl] CB 4 SCOT [pl] atm B, [fl] atm B, [pl] Stirling [pl] Calculation
100% 90% 80% 70% 0%
10% 20% 30% Concentration of Hydrogen
Results of all appliances: Air ratio with increasing concentration of H2 1,6
CB 1, [fl] CB 2, [fl] CB 1, [pl] CB 2, [pl] CB 3 SCOT, [fl] CB 4 SCOT [fl] CB 3 SCOT, [pl] CB 4 SCOT [pl] Stirling [pl] Calculation
air ratio
1,5 1,4
Cold start with 30% H2 possible for all appliances
1,3 1,2 0%
10% 20% 30% Concentration of Hydrogen
Results of SCOT controlled appliances: Air ratio with increasing concentration of H2 1,6 CB 3 SCOT, [fl] CB 4 SCOT [fl] CB 3 SCOT, [pl] CB 4 SCOT [pl] Calculation
air ratio
1,5 1,4 1,3 1,2 0%
10% 20% 30% Concentration of Hydrogen
CO- Emission [mg/kWh]
Results on all appliances: CO-Emission with increasing concentration of H2
70
CB 1, [fl] CB 1, [pl]
60
CB 2, [fl] CB 2, [pl]
50
CB 3 SCOT, [fl] CB 3 SCOT, [pl]
40
CB 4 SCOT [fl]
30
atm. B, [fl]
20
Stirling [pl]
CB 4 SCOT [pl] atm. B, [pl]
10 0 0% 10% 20% 30% Concentration of Hydrogen
NOx-emissions decrease with increasing H2-concentration
Next step: Field test in an existing distribution grid
Distribution grid selected: 128 gas clients commercial client (CHP) gas consumption max. 140m³/h single supply point existing gas control station hydrogen injection in preparation
Klanxbüll and Neukirchen in Germany
Summary
No major problems up to 10% of hydrogen admixture. • No increase of CO, stable flame, cold ignition possible • Increasing air ratio (predictable) of about 0.05 • Decreasing load less than 5% Above 10% admixture first problems are observed. • Initial rise of CO at atmospheric burners • Increasing air factors may provoke noise • Decreasing load more than 5% • Electric efficiency for micro CHP decreases Combustion Control behavior has to be optimized. Further lab tests on different appliances are needed. Further tests in existing distribution grids are needed.
Thanks for your Attention
Results on a typical condensing boiler with combustion control 1.9
80
1.8
70
1.7
60
1.6
50
1.5
40
1.4
30
1.3
20
1.2
10
1.1
0
1 Erdgas H
G20
95% G20 90% G20 85% G20 80% G20 10% H2 10% H2 15% H2 20% H2
ηtherm full load
ηtherm partial load
λ full load
G222
70% G20 30% H2
G21
G231
λ partial load
70 60 50 40 30 20 10 0 Erdgas H
G20
95% G20 10% H2 NOx full load
90% G20 10% H2
85% G20 15% H2
NOx partial load
CO full load
80% G20 20% H2 CO partial load
G222
70% G20 30% H2
Air Factor
2
90
Emissions (mg/kWh)
Thermal Efficiency (%)
100
Results: No CO-increase Stable flame, Cold ignition possible No effect on efficiency, But: Combustion control does not correct the airfactor
Appliances investigated on the test stand at E.ON Ruhrgas
2 atmospheric boilers 2 condensing boilers 2 condensing boilers combustion control 1 Mikro CHP Stirling 1 commercial boiler
rib burner, flat water cooled burner perf. flat ceramic burner perf. cylindric metal burner Half spheric metal mesh burner perf. flat metalic burner
Jet burner
Deviation of characteristic values with increasing admixture of hydrogen
110%
Deviation
100% 90% 80% 70% 60% 0%
10%
20%
30%
Concentration of Hydrogen Wobbe number
Gross calorific value
air requirement
