Experiencing gas quality
change in real. Can sensors
help?
Jesper Bruun
Energinet.dk
[email protected]
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Expansion of the Danish Gas Transmission System
North
Sea
Sweden
•Since 2010 new import
point at Danish/German
border
W: 15.0 – 15.5
•Increased import
capacity from October
2013
W: 13.9 – 15.3
Germany
Titel
2
First gas quality variations appears almost
instantly
Øvre brændværdi målt i Ellund, Egtved og Dragør
Gross calorific value in Ellund, Egtved and Dragør
Øvre brændværdi (kWh/Nm3)
14
13
12
11
Dragør
Titel
Egtved
20
21
18
-o
kt
-2
01
0
22
17
-o
kt
-2
01
0
23
16
-o
kt
-2
01
0
00
15
-o
kt
-2
01
0
01
Ellund
15
-o
kt
-2
01
0
02
14
-o
kt
-2
01
0
03
13
-o
kt
-2
01
0
04
12
-o
kt
-2
01
0
05
11
-o
kt
-2
01
0
10
-o
kt
-2
01
0
09
-o
kt
-2
01
0
06
10
Wobbe index variations
4
Frames for gas qualities
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Wobbe variation in Southern Denmark and in Northern Germany
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Notes to wobbe index variation
• The Danish legislation allow Wobbe between 13.9 kWh/Nm3 and 15.5
kWh/Nm3 (25/0)
• A span of 1.6 kWh/Nm3
• The complete span is almost used today
• The maximal variation within a day is 1.24 kWh/Nm3
• The difference between the highest and lost hourly value is in the same period
0.97 kWh/Nm3
• Few (maybe none) other location in Europe experience this size of variation.
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Gas sensors – can they help?
• Gas appliances with adjustable air gas ratio
(like forced draught burners) is more critical
in relation to gas quality variations
if the gas quality at service is unknown
• This is the case for both small and large forced
draught burners
• A portable gas sensor device making a robust
estimation of the wobbe index would be a great help
for the installers doing maintenance
• Information about the actual wobbe index of the gas
at the consumer would help the adjustment
• This could be a key step towards a harmonized
broader wobbe index range in Europe.
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Conclusion
• Denmark has since 2010 experiences big gas quality variations due to new
import.
• Large variations – even on daily or hourly basis
• Though the new gas qualities have been handled well by appliances and
consumers - challenges is recognized for the next steps.
• Thoughts about gas sensors:
• Gas sensors could play key role in an implementation of a broader
harmonized gas quality specification
• Gas sensors could help installers at service tasks if they are portable, accurate
and cheap enough
• Gas sensors could help industrial consumers for control of large appliances
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