Enhancement of Helium Gas Recovery system at IPR

J.C. Patel

Cryogenics Division

Institute for Plasma Research, Bhat, Gandhinagar

Outline

Brief Introduction of present Helium gas Recovery System

Technical specifications of Bauer & Linde Recovery Compressors

Total requirements of Helium Gas Recovery system for full fledge SST-1 operation as well as NBI cryo system and MEL Experiments

Reference He Recovery system Data from other Fusion Machines

Capacity Enhancement proposal for Helium Gas recovery system

Technical specifications of proposed Helium Gas recovery system

Budgetary Requirements

Brief Introduction of present Helium gas Recovery System

Helium Gas Recovery system

Recovery compressor

     100 NM3/hr (1 no.) (Bauer)

        29 Nm3/hr (1 no.) (Linde)

Total Helium Gas Recovery maximum 129 Nm3/hr

 Gas bag:

40 Nm3; 2 nos. at compressor hall

40Nm3, 1 no. at cryo-lab (MEL)

Bauer

Linde

Secant

HV976 HV977

HV978 HV979

HV980HV970

NRV981

Bellow

( Currently Disconnected)

TO HV975

For Gas Filling

Gas Bag2

PSH976

Gas Bag1

Gas Bag3

Cryo LabSafety Disc2Safety Disc1

Blower

P & ID of Helium Recovery system

Technical Specs of Helium Recovery system

Bauer Helium Gas Recovery system (Model G 25.9-45)

Model G 25.9-45 : 5 stages reciprocating compressor

Delivery of Helium Gas :1650 L/Min.

     100 NM3/hr

No of Stages : 5 Maximum Pressure at discharge 160 Bar

Suction Pressure : 1 Bar

Drive motor : 45 KW,440V, 50Hz, 2950 RPM

Dryer Unit : Secant IV , Flow rate 1500-3500 L/Min.

Due point of Dried medium: -20 degree C

 Saur Helium Gas Recovery system (Supplied By Linde)

Delivery of Helium Gas     29 Nm3/hr at Suction pressure of 1 bar

No of Stages : 4

Maximum Pressure at discharge: 150 Bar

Drive motor : 15 KW,440V, 50Hz, 1440 RPM

Total Helium Gas Recovery maximum 129 Nm3/hr

Photograph of present He Recovery Units at IPR

Total requirements of Helium Gas Recovery system for full fledge SST-1 operation as well as NBI cryo system and MEL Experiments

Operation Scenario of He gas Recovery CompressorDuring Normal Operation:

SST-1 Operation along with NBI cryo plant

Case:I Basis of Sizing He recovery system (without LP Return)

Steady state Heat load on SCMS : 200 W @ 4.5 K

200 / 3.0 l/h ~ 65 l/h [Equivalent Liquefaction capacity]

10 pairs of Current leads will evaporate : 200 l/h @ 4.2 K

NBI cryo plant is 100 W at 3.8 K and 140 W @ 4.5K

140 / 3 l/h ~ 48 l/h [Equivalent Liquefaction capacity]

Total: 320 l/h = 320 x 700 l/h gas at NTP = 225 m3/h

Total dead volume of LHe stored in MCD = 800 L

Case:II During the plant failure, half of the LHe volume is expected to evaporate within 2 hours @ 200 l/h

Other than this requirements there is an abnormal Operation in SST-1

e.g. Quench of SCMS or sudden vacuum break in NBI system

Huge amount of gas can come out depends upon type of fault and its magnitude.During Emergency Power Shutdown, If DG does not operate and long term power shut down take place then we might have to loose the gas in Atmosphere, there is no way to Recover this gas Helium.

Finally, the required capacity: 225 Nm3/h whereas we have only 129 Nm3/h

Reference He Recovery system Data from other Fusion Machines

Capacity Enhancement proposal for Helium Gas recovery system

Looking at the recent incident of one of the He gas balloon got ruptured during the SHe operation while power got shutdown, at that time around 650 L of LHe was stored in MCD. Due to this event approximately 245 NM3 of Gas accumulated in the Helium recovery system and Gas balloons were heavily tight with over pressure of 1.5 bar in very small time scale of minutes where even the recovery system was functioning with safety device in place and working. Finally, due to aging of Rubber, one of the Gas balloon got ruptured.

What we learnt from this incident ?We need to enhance the capacity of recovery system.

Therefore, we propose to have other Recovery compressor in parallel with the existing one of Bauer make with capacity of 1900 l/min = 100 NM3/h at 160 barWe have already indented 02 numbers of reliable Gas bags of volume 40 m3 each on faster time scale.

At the same time, we took action to repair the ruptured Balloon on top priority.

Technical specifications of proposed Helium Gas recovery system

Technical specs of Recovery compressor [Bauer, Germany Make]

- Medium: Helium

- Working pressure: Suction @ 1 bar and Discharge @ 160 bar

- Working Temperature: +5 – 45 degree C

- Speed: 1180 rpm

- Capacity: 1800 l/min = 108 Nm3/h

- No. of Compressor stages: 05

- Type of compressor: Reciprocating type

- Electrical Motor: 45 kW, 415 V, 50 Hz, 1450 rpm

- Drive: V-belt

- Spare kit: Maintenance kit for 1000 Hrs/ 2000 Hrs and 4000 Hrs.

- Additional Lubrication Oil for 2000 Hrs of operation

- Features:

Fully Automated start up machine

Supervision / display of all process and operation parameters

Shut down in case of deviation from specified operation parameters

Display of operation data, Error / Fault indications

Maintenance data and guidelines

Budgetary Requirements

Only M/s. Bauer is manufacturing this machine with B- control is a PLC based with largest capacity machine. [Proprietory based]

As we have already installed one unit in Compressor Hall and last 8 years it is working satisfactory.

The approximate cost of this machine is about 90 lacs [w/o dryer unit]

The spare kit cost is about 10 lacs.

If we have to buy the dryer unit then there will be an additional cost of 35 lacs.

Total budget required for this Recovery system is about 1.35 Crores.

Many Thanks for your Kind Attention