1. Cryoplant Operation for FLASH and XFEL
Betriebsseminar, Grömitz T. Schnautz

2. Cryoplant Operation for FLASH and XFEL
Overview:
The present cryogenic system
The cooling process
Cryogenic availability
Upgrades
Reconstruction of the cryoplant for XFEL, FLASH….
Operational experience
Conclusion
Betriebsseminar, Grömitz T. Schnautz

3. Cryoplant Operation for FLASH and XFEL
Overview:
The present cryogenic system
Betriebsseminar, Grömitz T. Schnautz

4. Cryoplant Operation for FLASH and XFEL
The refrigerating plant:
Three cold boxes
Three oil-adsorbers
plus redundancy
Three pairs of dryers
plus redundancy
Three sets of compressors
plus redundancy
Two low temperature purifiers
Distribution box
Dewars
Betriebsseminar, Grömitz T. Schnautz

5. Cryoplant Operation for FLASH and XFEL
Flow-scheme of (one) present refrigerating plant:
Distribution Box
Cryogenic
Purifier
HP-Compressor
Purify-Units
Cold Box
Consumer
LP-Compressors
Betriebsseminar, Grömitz T. Schnautz

6. Cryoplant Operation for FLASH and XFEL
Flow-scheme of the present refrigerating plant:
Compressors
Cold Box
Distribution Box
(1)
HERA North
HERA South
(2)
FLASH, CMTB, MTH …
(3)
Dewars
Redundancy:
Betriebsseminar, Grömitz T. Schnautz

7. Cryoplant Operation for FLASH and XFEL
Overview:
The present cryogenic system
The cooling process
Betriebsseminar, Grömitz T. Schnautz

8. Cryoplant Operation for FLASH and XFEL
The Cooling Process:
Flow-scheme of HERA cold box
Betriebsseminar, Grömitz T. Schnautz

9. Cryoplant Operation for FLASH and XFEL
The Cooling Process:
Simplified flow-scheme of HERA cold box
Claude-Prozess, Flüssigkeits-Kältekreislauf
K Kompressor
I, II, III Wärmeaustauscher
E Expansionsmaschine
JT Joule-Thomson-Ventil
FL Flüssigkeitsbehälter
V Heliumgas-Vorratsbehälter
Betriebsseminar, Grömitz T. Schnautz

10. Cryoplant Operation for FLASH and XFEL
Overview:
The present cryogenic system
The cooling process
Cryogenic availability
Betriebsseminar, Grömitz T. Schnautz

11. Cryoplant Operation for FLASH and XFEL
Availability:
Throughout 17 years of HERA-operation the refrigeration plant
compensated the cryogenic loads of the HERA accelerator,
the HERA experiments and temporarily the FLASH accelerator
and other recipients with a corresponding availability of 98.7 %.
Related to the availability of the refrigeration plant itself
this value exceeds 99 %.
A plant-availability of 99 % is possible if periodical maintenance as well as the exchange of critical components (O-ring sealings, power supplies, emergency-power supplies, PLC’s, etc) is carried out and redundancy exists.
Nevertheless: The refrigerating plant also has to cope with technical problems decreasing the availability.
Betriebsseminar, Grömitz T. Schnautz

12. Cryoplant Operation for FLASH and XFEL
Failures:
Item
Failure reason
Screw Compressors
fail to operate
shaft seal excess leak
capacity control fails to operate
Motors
ball bearing damaged
Oil pumps
oil leak > 5 l / 1000 hs
Control valves (air operated)
leak past the seat
Motor driven fan (oil cooler)
v-belt broken
Liquid He level sensor
erratic indication
Process control computer system
system fails to operate
crates fail to operate
Instrumentation, pressure transmitter, flow meter, …
erratic output
capillary plugging
Betriebsseminar, Grömitz T. Schnautz

13. Cryoplant Operation for FLASH and XFEL
Failure statistic:
But this is the failure statistic including
infrastructure of recipients!
Failure statistic of
refrigerating plant only.
All in all the controls caused a large relative fraction
of downtime but the system ran very stable through the
operation time of HERA and the absolute downtime
given by control failures was very low.
Betriebsseminar, Grömitz T. Schnautz

14. Cryoplant Operation for FLASH and XFEL
Overview:
The present cryogenic system
The cooling process
Cryogenic availability
Upgrades
Betriebsseminar, Grömitz T. Schnautz

15. Cryoplant Operation for FLASH and XFEL
Upgrades:
Upgrade of compressors with frequency converters
In total there were 14 slide valve controlled screw compressors (Aerzener) arranged in 3 sets plus 2 single compressors as redundancy.
One compressor set:
High pressure stage: 1 compressor, kg/s, 4.45 bar to 18 bar.
Low pressure stage: 1 turbine-flow compressor, kg/s , 2 bar to 4.45 bar
2 JT-flow compressors, kg/s, 1 bar to 4.45 bar.
Advantages due to upgrade of low pressure stages with frequency converters:
Avoids the bypass flow and the compressors can be run with optimal efficiency.
Less maintenance and failure rates by eliminating the slide valve positioning
hydraulics.
The frequency converter units are practically maintenance free.
18 % reduced energy consumption.
Enhancement of volume flow rate at low suction pressure.
Betriebsseminar, Grömitz T. Schnautz

16. frequency converter cabinets
Cryoplant Operation for FLASH and XFEL
Upgrades:
Upgrade of compressors with frequency converters
motor
srew compressor
frequency converter cabinets
Frequency converters in front of low pressure compressors
Betriebsseminar, Grömitz T. Schnautz

17. Cryoplant Operation for FLASH and XFEL
Upgrades:
Upgrade of oil blowers with frequency converters
Every compressor station has their own oil provision with a related oil re-cooling
So far the required air flow for cooling was regulated by a three-stage blower machine (750/1000/1500 rpm). The regulation of the blower machines worked in dependence of the measured oil temperature via a PLC.
An optimal adjustment of the blower machines’ rotational speed on the oil temperature was not possible
Advantage due to upgrade of oil blowers with frequency converters:
The rotational-speed range can stagelessly be adjusted from 200 rpm to 1500 rpm to enable an optimal oil re-cooling for the respective operating states.
Betriebsseminar, Grömitz T. Schnautz

18. Cryoplant Operation for FLASH and XFEL
Upgrades:
Change from the proprietary process control system EMCON D/3
to the open source system EPICS.
This conversion was started in 2002 for several plant components
and will be enlarged to the whole plant soon.
Advantages due to conversion to EPICS:
Enhancement of flexibility in operating the refrigeration plant.
Reduction of the operating costs in terms of maintenance and upgrading.
Betriebsseminar, Grömitz T. Schnautz

19. Cryoplant Operation for FLASH and XFEL
Upgrades:
Change to fieldbus communication at FLASH cryoplant
Started this year and will be finished completely before FLASH shutdown in ’09
First successful tests have been made – compressors were running with new fieldbus technology
Advantages due to conversion to fieldbus:
Reduced cabling complexity.
Higher availability and less failures due to shorter signal lanes.
More flexibility in terms of future extensions.
Betriebsseminar, Grömitz T. Schnautz

20. Cryoplant Operation for FLASH and XFEL
Upgrades:
Maintenance of critical components of FLASH cryoplant
Started this year and will be finished completely before FLASH shutdown in ’09
Critical components:
Compressors
Motors
Pumps
Savety valves, control valves
Oil coolers
PLC’s
Advantage due to maintenance of critical components:
Higher availability and less failures due to time worn components
Betriebsseminar, Grömitz T. Schnautz

21. Cryoplant Operation for FLASH and XFEL
Overview:
The present cryogenic system
The cooling process
Cryogenic availability
Upgrades
Reconstruction of the cryoplant for XFEL, FLASH….
Betriebsseminar, Grömitz T. Schnautz

22. Consequences Cryoplant Operation for FLASH and XFEL
Reconstruction of the Cryoplant for XFEL, FLASH….:
(Prearrangements during FLASH shutdown in ‘09)
Compressors
Cold Box
Distribution Box
(1)
HERA North
AMTF
HERA South
(2)
FLASH, CMTB, MTH …
(3)
Dewars
Consequences
Redundancy:
Betriebsseminar, Grömitz T. Schnautz

23. Cryoplant Operation for FLASH and XFEL
Consequences of prearrangements during FLASH shutdown in ‘09:
“only” redundancy for FLASH: redundant HERA compressors or 900 Watt plant
operation of proton ring is not possible anymore
HERA South transfer line is cut
operation of electron ring only with huge effort possible
cavities have been provided via HERA South transfer line
no cryoplant operation during FLASH shutdown
consumers are already informed
no provision with liquid helium
operation of KOMAG not possible any more
KOMAG has been provided via HERA South transfer line
KOMAG space is needed for the reconstructed XFEL cryoplant
Betriebsseminar, Grömitz T. Schnautz

24. Cryoplant Operation for FLASH and XFEL
Reconstruction of the cryoplant for XFEL, FLASH….:
(The future XFEL cryoplant)
Compressors
Dewar
Cold Box
(1)
XFEL
(2)
2 K Box:
Distribution Box
&
Cold Compressor Box
Redundancy:
Betriebsseminar, Grömitz T. Schnautz

25. Cryoplant Operation for FLASH and XFEL
Reconstruction of the cryoplant for XFEL, FLASH….:
(The future XFEL cryoplant-connection of cold boxes with 2 K box)
Betriebsseminar, Grömitz T. Schnautz

26. Cryoplant Operation for FLASH and XFEL
Reconstruction of the cryoplant for XFEL, FLASH….:
(The future XFEL cryoplant)
Compressors
Dewar
Cold Box
(1)
2 K part: 1 bar, 2.2 K
XFEL
(2)
2 K Box:
Distribution Box
&
Cold Compressor Box
Redundancy:
Betriebsseminar, Grömitz T. Schnautz

27. Cryogenic units of 12 cryomodules = ‚strings‘
Cryoplant Operation for FLASH and XFEL
Reconstruction of the cryoplant for XFEL, FLASH….:
(Cryogenic supply of XFEL)
Cryogenic units of 12 cryomodules = ‚strings‘
String Connection Box
Betriebsseminar, Grömitz T. Schnautz

28. Cryoplant Operation for FLASH and XFEL
Reconstruction of the cryoplant for XFEL, FLASH….:
(The FLASH… cryoplant)
Dewar
HERA North
Old distribution box
AMTF
FEL subcooler box
Compressors
FLASH
Cold Box
SMES
CMTB
MTH
Redundancy:
Betriebsseminar, Grömitz T. Schnautz

29. FEL-Vorkühlerbox im FEL-Kryoanbau
Cryoplant Operation for FLASH and XFEL
Reconstruction of the cryoplant for XFEL, FLASH….:
(The FLASH… cryoplant)
FEL-Vorkühlerbox im FEL-Kryoanbau
Verzweigung auf Linac ( + SMES und CMTB)
Betriebsseminar, Grömitz T. Schnautz

30. Cryoplant Operation for FLASH and XFEL
Reconstruction of the cryoplant for XFEL, FLASH….:
(The FLASH… cryoplant)
Heliumkompressoren ( Drehschieber + Rootsgebläse)
jeweils 10 g/s bei Verdichtung 10 mbar -> 1.05 bar
zwei komplette (fast) identische Straßen: VC1 und VC2
Betriebsseminar, Grömitz T. Schnautz

31. Externer Niederdruck-Wärmetauscher ( IHEP,Russland
Cryoplant Operation for FLASH and XFEL
Reconstruction of the cryoplant for XFEL, FLASH….:
(The FLASH… cryoplant)
Externer Niederdruck-Wärmetauscher ( IHEP,Russland
Gegenstromwärmetauscher:
3,5 K / 31 mbar > K / 29 mbar
7,5 K / 12 bar < K / 12 bar
Betriebsseminar, Grömitz T. Schnautz

32. Cryoplant Operation for FLASH and XFEL
Reconstruction of the cryoplant for XFEL, FLASH….:
(The FLASH… cryoplant)
Betriebsseminar, Grömitz T. Schnautz

33. Cryoplant Operation for FLASH and XFEL
Overview:
The present cryogenic system
The cooling process
Cryogenic availability
Upgrades
Reconstruction of the cryoplant for XFEL, FLASH….
Operational experience
Betriebsseminar, Grömitz T. Schnautz

34. Cryoplant Operation for FLASH and XFEL
Operational experience:
shift system
6 shift crews
always at least 1 operator on shift
Betriebsseminar, Grömitz T. Schnautz

35. Cryoplant Operation for FLASH and XFEL
Operational experience – cooperation with FLASH operators:
In general the communication with FLASH operators or persons in charge concerning planned (FLASH-)operating modes is good, and…
the cryoplant(-operation) is flexible in terms of (spontaneous) changing operating modes of FLASH, but…
…single (enduring) quenches can already lead to a stop of the cryogenic provision of FLASH or make it impossible to hold the required temperature level… fluctuations/failures in the cryoplant
Cryoplant operators notice quenches by raised pump flow and/or raised temperatures at cavities …..
He - pump
30 mbar = 2 K
Betriebsseminar, Grömitz T. Schnautz

36. Cryoplant Operation for FLASH and XFEL
Operational experience – cooperation with FLASH operators:
He - pump
30 mbar = 2 K
Cryo OK is linked to level and pressure in liquid helium sump
Lowering the power input before Cryo OK is lost
FLASH operator should lower the power input when informed about an assumed quench by a cryoplant operator
Cryo-independent quench detection by low level RF?!
Betriebsseminar, Grömitz T. Schnautz

37. Cryoplant Operation for FLASH and XFEL
Conclusion:
The demands of the HERA refrigerating plant were and still are very high.
In the course of the years changes were made regarding hardware as well as software always to remain on the state of the technology and to ensure a high availability of the plant.
Overcapacity or rather redundancy was essential to reduce the refrigeration plant’s downtime to a minimum.
The experience has shown that redundancy must be given and special attention must be paid to the helium compressors and the electricity supply, in particular to the process computers and the process control system.
Betriebsseminar, Grömitz T. Schnautz