Cryogenic Engineering Education at NIT Rourkela

Sunil Kr SarangiDirector, NIT Rourkela

NIT Rourkela

• Established in 1961 as the Regional Engineering College

• Converted to National Institute of Technology in 2002

• 9 Engineering, 3 Science and 1 Social Science Departments

• Faculty: 180 (120); Students 1700; Supporting Staff 350

Department of Mechanical Engineering

• Faculty Strength : 25 (17)• Students :

– B Tech : 80 x 4– M Tech :

– Machine Design– Production Technology– Thermal Engineering

– M Tech by Research• Ph D Programme

Refrigeration & Cryogenics Group

Prof Sunil Kr SarangiProf Ranjit K SahooProf Ashok SatpathyProf Alok SatpathyProf Subhas Haldar (on leave)

Cryogenic Engineering LaboratoryMajor Equipment

• Cryomech Liquid Nitrogen Generator Based on GM refrigerator– Capacity 40 litre per day

• INOX Dewars– 200 litre (5 bar), 2 x 30 litre, 3 litre

• Thermax steam generator – 500 kg/hour, 10 bar

• Vacuum Techniques (Bangalore) High vacuum pumping station - 500 litre/second

• Alcatel Vacuum Leak Detector• Miscellaneous Instruments

Cryogenic Engineering Laboratory

R&D Activities• Screw compressor (BRNS)• Expansion Turbine• Heat Exchangers• Heat and Mass Transfer• Programmable Cryochamber for Cryotreatment of

Cutting Tools• Pulse Tube Refrigerator• Laboratory nitrogen liquefier and refrigerator• Helium Purifier

STUDIES ON OIL INJECTED STUDIES ON OIL INJECTED TWINTWIN--SCREW COMPRESSORSCREW COMPRESSOR

STUDIES ON OIL INJECTED TWINSTUDIES ON OIL INJECTED TWIN--SCREW COMPRESSORSCREW COMPRESSOR

Development of a Mathematical model to relate the performance of a screw compressor to design and operating parameters.Conversion of a cheap Air compressor for Helium applications.Study of purification techniques to ensure oil free gas delivery suitable for cryogenic applications

Animation of 5-6 lobe combination rotors; casing removed for clarity

Suction Entrapment Compression Discharge

Working mechanism of twin screw compressor

Schematic view of experimental setup at NIT Rourkela

Pd/Ps=8.65;RPM=4350

40

46

52

58

64

70

76

82

88

94

100

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16

Interlobe clearance(mm)

( ηtv%

)

AirNitrogenArgonHelium

ComparisonComparison volumetric efficiency of different gases at a fixed volumetric efficiency of different gases at a fixed male rotor rotational speed with male rotor rotational speed with interlobeinterlobe clearance at a fixed clearance at a fixed injected oil temperature and suction conditions injected oil temperature and suction conditions

Tli=308K

84

86

88

90

92

94

96

2 3 4 5 6 7 8 9

Pressure ratio(Pd/Ps)

( ηv%

)

Air(exp)Air (calculated)Nitrogen(exp)Nitrogen(calculated)Argon(exp)Argon(calculated)Helium(exp)Helium(calculated)

Variation of volumetric efficiency of different gases with pressure ratio at a fixed injected oil temperature and suction pressure

Development of a Cryogenic Development of a Cryogenic TurboexpanderTurboexpander

Development of a Cryogenic Development of a Cryogenic TurboexpanderTurboexpander

The Expansion turbine is a basic component of a Cryogenic process plant

Air separation plantHelium or hydrogen liquefierLow temperature refrigerator

NIT,Rourkela has initiated a program for indigenous development of a turboexpander, in continuation of earlier work at IIT Kharagpur

4 Slots of 10mm width

17 blades equispaced

Blade details

Experiments with SINGLE STAGE PULSE TUBE

REFRIGERATOR

SINGLE STAGE PULSE TUBE REFRIGERATOR

OBJECTIVES:Design and development of single stage pulse tube refrigeratorDevelopment of rotary valve pressure pulsationDevelopment of Helium compressor

PRICIPLES OF WORKING

The gas must reach the low temperature point without carrying a lot of heat.The amplitude of the gas flow and pressure oscillations in the pulse tube section must be large enough to carry away the heat collected by to the cold heat exchanger, andThe phase relationship between the pressure and the gas flow in the pulse tube section must be appropriate to carry heat away from the cold point

Programmable Cryochamber

Programmable Cryochamber

Programmable Cryochamber

• Features:– Working volume = 300 x 300 x 300 mm– Temperature controlled to about 1 K by PID

control – Temperature range: 300K to 90K

Programmable CryochamberComponents

– Stainless Steel Housing– Thermocole insulation– Cryogenic solenoid valve– Fan for air circulation– Heater– RTD Temperature sensor– ADAM data acquisition modules

Programmable Cryochamber

Applications– Good for Cryotreatment of cutting tools, dies,

punches – Poor in biological applications because of direct

spray of liquid nitrogen and lack of seeding facility.

Major New Initiatives

Experiments on Brazed AluminiumPlate Fin Heat Exchanger

Heat exchanger test core with steam entry and exit ducts ( IIT Kharagpur)

Photograph of the experimental rig at IIT Kharagpur ;New programme initiated at NIT Rourkela.

0.5 0.6 0.7 0.80.9 1 2 3 4 5 6 7 8 9

0.01

0.110.2 W 0.152 18 (Al)

St.Pr2/3

f (Hot Test)

St.Pr2/3 (Kays) f (Kays) f (Cold Test)

f -

fact

orj -

fact

or

Re x 10-3

Thermo-hydraulic characterization of the calibration heat exchanger (IIT Kharagpur results )

Development and Study of an Indigenous Helium Purifier based on Low Temperature

High Pressure Adsorption of Impurities( Submitted to BRNS )

INVESTIGATORSINVESTIGATORSPI: Prof Sunil Kr Sarangi, NIT RourkelaCI: Prof Ranjit K. Sahoo, NIT Rourkela

Prof P. K.Das, IIT KharagpurPC: Mr. R.Dey, VECC, KolkataMr. Trijit K.Maity, VECC, Kolkata

• In liquid helium applications (e.g. superconducting magnets), boil-off helium gas is collected in gas bags, compressed and re-liquefied.

• In the process, the gas is contaminated with air impurities (nitrogen, oxygen, moisture, CO2)

• Removal of impurities is essential to avoid blockage of orifices and valves, deposition on heat transfer surfaces and solid impurities hitting turbine blades.

• On-line purifiers are often inadequate to handle high impurity concentrations.

Project Objectives

– To design and build an adsorption based helium purifier, and to study its performance

– To create proper documentation (design details, selection of equipment, fabrication and testing methods) for future construction and technology transfer.

Specifications :Raw gas flow rate = 20 m3/hr.Adsorption pressure > 120 to 150 bar.Adsorption temperature = 77 K.Inlet impurity conc. = upto 50%air in helium.Outlet impurity < 100 ppm air in helium.

Elements of the Proposed Project 1. Determination of specifications of the purifier.2. Process design.3. Component specifications.4. Design or selection of components.5. Procurement and fabrication of components.6. System integration.7. Testing and performance studies.8. Improvement of design.9. Documentation.10. Technology Transfer.

Selection of Equipment :Compressor : 1 bar to 150 bar, 3 or 4 stages

ReciprocatingFlow rate = 20 m3/hrOptions: Bauer (Germany)

John Sauer (Germany)TEC (Korea)

Helium Purity Monitor - ImportedVacuum Vessels – Fabricated commerciallyValves & Fittings – Swagelok, ParkerOther accessories – To be procured

Experimental Programme :• Actual impure helium flow rate and pressure drop in

different components.• Actual product purity (expected purity 99.99%) as a

function of input purity level.• Maximum tolerable air impurity.• Maximum tolerable moisture impurity.• Capacity of purifier (nm3 of pure helium) before

regeneration as a function of input purity.• Liquid nitrogen consumption

– quantity of LN2 consumed per regeneration cycle.– quantity of LN2 consumed per nm3 of pure helium as a function of

input impurity.• Time and power input for regeneration.

Deliverables :• Two completely functional purifier units

delivering 99.99% pure helium, 50 to 100 m3 per six-hour shift. [One unit will be delivered to VECC, while the other is retained in the PI’s laboratory].

• A well documented design and fabrication procedure, and

• Complete performance study along with comparison with theoretical prediction.

DEVELOPMENT OF TURBOEXPANDER BASED CRYOGENIC REFRIGERATOR AND

LIQUEFIER( Submitted to BRNS )

INVESTIGATORSINVESTIGATORSPI: Prof Sunil Kr Sarangi, NIT RourkelaCI: Prof Ranjit K. Sahoo, NIT RourkelaCI: Prof G. Venkatarathnam, IIT MadrasPC: Mr. Trilok Singh, Head, Cryogenic

Division, BARC

Heat Load

AftercoolerCompressor

HeGas Bag

Load Turbine

Load Turbine

2 3 4

89

5

67

1

Cryogenic refrigerator (Tref > 4.2 K) based on modified Collins cycle: Process Flow Diagram

3

4

HX3

HX2

HX1Compressor

EE

9

8

Specific Entropy (s) [J/kg. K]

p = LP

p =

LP

p = HP

p =

HP

Tem

per a

ture

( T) [

K]

2

75

6

1

Heat Load

Cryogenic refrigerator (Tref > 4.2 K) based on modified Collins cycle: Temperature Entropy Diagram

Constituents of a Cryogenic process plant

Hardware1. Compressor (Reciprocating or Screw)2. Heat Exchangers (wound finned tube, plate fin,

matrix)3. Expansion engine/turbine4. Expansion (JT) valve5. Plumbing6. Instrumentation and controls7. Vacuum vessels

Brainware8. Process Design9. Selection of equipment10. System integration11. Operation and testing

The Proposed ProjectTarget :

1. To construct a turbine based refrigerator with following specifications :- Working Fluid : Helium- Ultimate Temperature : 50K- Cooling Load : 2 kW at 80K

2. To use the same device with Nitrogen as working fluid to realize a laboratory scale liquid nitrogen generator. Expected production rate: 20 lit/hr

The Proposed Refrigerator System

1 27 3

4

56Aftercooler

Gas Bag

Nitrogen

Compressor

Heat Load

Load Turbine

Cold Box

Proposed Cryogenic refrigerator (Tref = 80 K) based on Reverse Brayton cycle and using a heat exchanger of effectiveness less than unity: Process Flow Diagram

p =

LP

p =

HP

267

1

p = LPp = H

P

Specific Entropy (s) [J/kg. K]

Tem

pera

tur e

(T) [

K]

HX

Compressor

3

Heat L

oad4

5EE

Proposed Cryogenic refrigerator (Tref = 80 K) based on Reverse Brayton cycle and using a heat exchanger of effectiveness less than unity: Temperature Entropy Diagram

Liquid Nitrogen Generator

Compressor

Load EE

ExpansionEngine

1A

ir P

urifi

er

Coolingwater

2 3

8

4

7

5

Expansion Valve

Phase Separator

HX1 HX2 HX3

Liquid Air

Isothermal

Dry air (CO free)2

6g

f

Raw Air

Air/Nitrogen liquefier based on Claude cycle and using ideal heat exchangers: Process

Flow Diagram

3

4

HX3

HX2

HX1

Compressor

EE

8

Specific Entropy (s) [J/kg. K]

p = LP

p = L

P

p = HP

p = H

P

Tem

pera

tur e

(T) [

K ]

2

75

6Phase separator

f g

1

Exp valveh = Constant

Air/Nitrogen liquefier based on Claude cycle and using ideal heat exchangers: Temperature Entropy Diagram

Components of Proposed Refrigerator and Liquefier

• Compressor : Existing Screw CompressorMake : Kaeser, GermanyPressure Rating : 10 barFlow Rate : 300 m3/hrPower : 37 KWWorking Fluid : Nitrogen / Helium

• Expander :

Technology developed for turbine of matching capacity with gas lubricated bearings.

Needs more work : fine tuning, reliable operation, performance improvement.

• Heat Exchangers :

Plate fin heat exchangers to be procured from BHPV, Vishakhapatnam, or Apollo heat exchangers.

Design capability exists at NIT.

Propose to try wire-wound coiled tube and printed circuit heat exchangers.

• Plumbing, Instrumentation & Controls :To be procured.

• Vacuum Vessel, insulation etc :To be procured.

• Process Design :- Capability available at NITR and IIT Madras.

• System Integration, Operation and Improvement :- to be pursued as part of the project.

The future :

• Fully established indigenous technology on turbine based refrigerators and liquefiers– Laboratory scale nitrogen generator– 10-20 K Refrigerator– Laboratory scale helium liquefier– Liquefiers for hydrogen, natural gas and special

gases

Thank You