1. Systems and methods for the determination of
odorants and other sulfur components in natural and liquid gas
Axel Semrau GmbH & Co KG
Dipl.-Ing. Frank Sasse

2. Topics Axel Semrau GmbH & CO, the company Odorization ODOR handy
ODOR on-line
Field Study

3. The company
Axel Semrau®, a company of 44 employees, with a technical staff of 34, comprising mostly chemists (PHD) and also some electronic and information technology engineers.
Since 1973 Axel Semrau as a person later his company is involved in sales and support for analyzers of odorant sulfur compounds

4. Lab for odorization control and gas analysis

5. Axel Semrau GmbH & Co services
Hardware service, repair and maintenance
Supply of calibration gas
Training on site and in the AS training center
Seminars on all topics related to the analysis and monitoring of odorants in gas.

6. Odorization
Methane CH4 (major component of natural gas) is without any smell.
Natural gas is also often without any smell.
If it smells, that is caused by natural sulfur.
The concentration of natural sulfur is continuously changing.
For a constant and typical smell an odorant is added.
Main reason: Everybody should be able to detect (smell) any leak in a house installation.

7. Gas production sometimes strong smell, very high sulfur content (sour gas)
Desulfurization not always necessary
Transport
Odorization
Distribution

8. Odorants
Strong and typical smelling organic sulfur components of the substance classes
Sulfides R-S-R
Mercaptans R-S-H

9. Odorants for natural gas
THT (Tetrahydrothiophen)
TBM (Tertiary butyl mercaptan)
Blends
Scentinel® E and Spotleak® (TBM 75%, IPM 16%, NPM 8% )
Scentinel® TB (50% TBM, 50%THT)

10. Odorants for LPG (liquid gas)
LPG: Propan / Butan
EM Ethylmercaptan
MM Methylmercaptan

11. German Regulation G280 Level of odorant intensity

12. German Regulation G280
Gas should reach a warning smell (level 2) before it reaches a concentration of 20% from LEL (lower explosion limit).
Similar regulations in other countries

13. Calculation of the minimum odorant concentration in gas
K C = mg/m % * LEL
(LEL = Lower explosion limit)
Example: TBM in natural gas ,03 mg/m³ C= = 3.8 mg/m³ TBM Minimum conc ,20 * 0, entration in Germany

14. Why do we have to check the odor level at all?
Odorization control
Why do we have to check the odor level at all?

15. Mechanical problems Odorant rate is not correct
Bypass odorizer (difficult to adjust)
Injection pump (mechanical failure)
Pump injects only air
Pump is getting no impulse
Remote control broken
Failures caused by operators

16. Chemical and physical problems
Chemical oxidization (especially mercaptans) and adsorption (specially THT)
The loss of odorant is depending on the flow and temperature. New PE pipes can also cause a problem.
=>This means you have a big loss of odorant from the point of injection to the households!
e.g: Injection 20mg/m³ THT Concentration at the last point 9mg/m³
=>It is very important to measure the concentration at the end point of the distribution net!

17. Measuring methods Smell the gas
Advantage: You smell it!
Disadvantages: different results from different people
Lower results after several measurement in a short time
Inaccurate
Good as an additional backup.
In European Countries are not used any longer

18. Measuring methods Measuring tubes
Advantage: simple to handle, low investment costs
Disadvantage: Many cross sensitivities, Very inaccurate
Due to low accuracy not allowed in Germany any longer

19. ODOR handy

20. ODOR handy
Proofed by extensive testing by many well recognized gas institutes, DVGW institute (Germany Gas Institute) for instance
Proofed by hundreds of companies, using it in daily routine work all over the World eg. (Italy, Spain, France, Poland, Czech Rep., Mexico, Argentina, Brazil, Chile, Bolivia)
Several customers have more than 20 units in use

21. Differences between THT and Mercaptan version
ODOR handy TBM
Display 00.1
Measuring range 0 to 50 mg/m³
For all mercaptans and blends with a high mercaptan concentration
Special version with US units (lbs/MMFC) and display 0.01 available
ODOR handy THT
Display 000
Measuring range THT 0 to 100 mg/m³
For THT and blends with high THT concentration

22. ODOR handy in the field
Connect direct to the gas pipe if pressure is 20 mbar (approx. 15 inch of water, 0.5 psi) or with a rotameter if the pressure is higher.
Wait just a few minutes
Read the result
Ready for next measurement after 10 minutes

23. Odorant concentration direct in mg/m³
Mercaptane ansprechen

24. Operation state No OFF switch Sensor should always have voltage
In case of empty battery or new sensor: => let the sensor stabilize up to 12h => then calibrate the ODOR handy

25. ODOR handy Ex-proof Can be used everywhere on site
Easily connected to the gas pipe by means of a very short non adsorptive tube
Weight approx. 100g
Selective alarm levels
Simple calibration procedure
Ex-proof battery (6 months continuous work)
Rechargeable battery ex-proof optional

26. Calibration gas set ISO 19739 (ISO 6326 T2)

27. ODOR handy

28. Calibration Battery check
Zero point check, adjust if necessary (screw 7)
Pure calibration gas pressure regulator
Connect calibration gas to ODOR handy
Wait till the reading is stable
In case of differences: - adjust span/amplification (screw 8) - disconnect calibration gas and wait 10 minutes. - Repeat in case of bigger differences.

29. Life time sensor Sensor has to be replaced if:
THT: Ce-value is higher TBM: Sensor has not enough sensitivity to adjust during calibration
H2S filter is saturated.
Life time of sensors is about 1-2 years, depending on usage.
(Sensors age, even if they are not been used.)

30. ODOR on-line

31. conform to ISO 19739 (German standard DIN 51 855-07-GC/ASTM D7493-08)
gas chromatographic procedure for online measurement (stationary and mobile)
for more than 30 years successful operating
since 1996 with ODOR on-line systems are always on the latest technical standard
2010 about 300 instruments on the market

32. Major applications
1. Natural sulfur compounds (e.g H2S, mercaptans) in natural gas
Underground gas storages
Gas power plants
Transmission pipes
Gas quality stations
H2S causes corrosion to pipes and turbines

33. Major applications 2. Odorization control
City gates
Pressure regulation stations
Mobile measurement
Odorants fade during transportation!

34. Installation In the field for on-line application
In the lab for manual operation (analyzing of samples)

35. References E-on Ruhrgas (Germany) RWE (Germany) Fluxys (Belgium)
Gas de France
TIGF (France)
Italgas (Italy)
Gas Natural (Spain, Brazil)
Peoples gas (USA)
Kindermorgan (USA)
Polish Oil and Gas Company (Poland)
Société Tunisienne de l’Electricité et du Gaz (Tunisia)
VCP Vychodoceska plynarenska, a.s (Czech Republic)
Igdas (Turkey)
EWE, Bayern Gas …… (Germany)

36. Stationary measurement
On-line measurement in a pressure regulation station

37. Stationary measurement
Processing with a special PC Software
ODOR control

38. ODOR on-line
Chromatograph designed to fulfill the demands of ISO (ISO 6326 T2)
packed column
electrochemical detector
10 ml gas sampling loop

40. Packed column

41. Heated column

42. Electrochemical detection Explanation of the expression
An electrochemical detector uses the oxidation ability of a substance as its proof. In the case of H2S and mercaptans the oxidation power of the chrome trioxide is used as the specific proof.

43. Detector

44. Detector tank front view

45. Insulated column and detector tank

46. Reservoir with distillated water for automated refill

47. Manual injection of low pressure samples

48. Injector for manual gas injections

49. Taking samples

50. ODOR control Software Easy to operate Real-time chromato- gram
User defined reports

51. ODOR control Software Database with all measure- ments Search filters
Export function to Excel™

52. ODOR control
Reportgenerator
User specific reports

53. Data output: 3 x 4-20mA (standard) or Modbus (optional)

54. Option Modbus
All results with name of the substances, retention time, areas and …
Groups of substances
8 different alarms
Status of the instrument
Information about the last run
:22: Update of Bus-Memory
:22:24 File: F:\ODO Results.xml
:22:24
:22:24 Parameter: Substance name TBM
:22:24 Value: TBM
:22:24 Type: String
:22:24 Start address: 0
:22:
:22:24 Parameter: Retention time TBM
:22:24 Value: 94
:22:24 Type: Single
:22:24 Start address: 10
:22:24 Parameter: Peak area TBM
:22:24 Value:
:22:24 Type: Int32
:22:24 Start address: 20
:22:24 Parameter: Concentration TBM
:22:24 Value: 2.8
:22:24 Start address: 30

55. THT in natural gas

56. THT and TBM in natural gas

57. Natural Sulfur and THT

58. complex mercaptan blends

59. Elution sequence of odorants

60. Odor on-line Measuring range Carrier gas Automatic and manual injector
THT mg/m³ - about 100 mg/m³
H2S mg/m³ - about 100 mg/m³
Mercaptans mg/m³ - about 100 mg/m³
Carrier gas
Nitrogen or compressed oil free air
Automatic and manual injector

61. Advantages of the electrochemical detector
The detector is not sensitive to other compounds in natural gas
Low detection limits 0.1 mg/m³
Linear within the normal measuring range
Extremely robust and stable in on-line applications

62. Mobile measurement 12 V use Heated column No cross sensitivities
Option: Electronically flow controller
Diesntleister mit bis zu 6 Fahrzeugen
Große GVUs haben eigen Fahrzeuge

63. electrochemical detector
operation
position
park / transport
position

64. Mobile sampling No sample transport.
Connect the instrument direct to the gas pipe

65. Service company: Schütz

68. measureing point

69. Measureing point

71. Comparission ODOR handy / ODOR on-line

72. Total Sulfur 1 ODOR on-line For H2S, natural mercaptans (and odorant)
2 ODOR on-lines One for H2S, natural mercaptans (and odorant) One for Carbonylsulfid (COS)
ODOR on-line plus ODOR total S II

73. Total Sulfur 1 ODOR on-line For H2S, natural mercaptans (and odorant)
Project with RMG
Container for BTU and sulfur measurement

74. Total Sulfur
b.) 2 ODOR on-lines One for H2S, natural mercaptans (and odorant) One for Carbonylsulfid (COS)

75. Total Sulfur
c.) ODOR on-line plus ODOR total S II

76. ODOR total S II

77. Field study Gas distribution net from Mark E Length: 563 km
Sales volume: Mio. kWh
customers:
City and area of Hagen
Stand December 2002 S

78. Measuring methods Stationary on-line measurement
Mobile measurement with a car
On demand: quick check with an ODOR handy

79. Sample sites

80. 1. Stationary on-line measurement
Data transmission to the central control station
Rechter Bildschirm: Statusmeldungen
Linker Bildschirm Messwerte
5 Anlagen

81. 2. Mobile measurement with a car
Small pressure regulation station
factory
Sampling point on the street
Public building (school)

82. Summary field study Mark E
Optimum control procedure for odorization level by:
On-line measurement (24h) ODOR on-line
Good positioning of sample sites
Flexible through a mobile gas chromatograph
Quick results from new sites with the handheld instrument (ODOR handy)