The document describes various cryogenic cycles used for liquefying gases, including the ideal liquefaction cycle, Linde-Hampson process, Claude cycle, and applications of liquefied gases like nitrogen, oxygen, and carbon dioxide. It also discusses the Joule-Thomson effect and inversion curve. Simulations of these cycles were performed using ASPEN HYSYS to analyze how parameters vary with pressure ratio, like molar flow increasing for ideal cycle. The Linde and Claude cycles were modeled fixing outlet conditions, determining heat exchanger properties and FOM. Cryogenic cycles help produce and utilize very low temperatures important for various industrial and scientific applications.

1. Study of Cryogenic Cycles
with ASPEN HYSYS Simulations
By: SURAJ SINGH PATWAL (11338)
PRADEEP MEENA (11339)
ASHISH ARYA (11361)
UDAYAVEER SINGH (11371)
ANURAG NEOTIA (11372)
RAVI KUMAR (10339)

2. Cryogenics
 Cryogenics is the science that addresses the
production and effects of very low
temperatures. (generally temperatures less
than -150oC)
 The word originates from the Greek words
'kryos' meaning "frost" and 'genic' meaning
"to produce.“

3. Liquefaction
 The process of refrigerating a gas to a temperature below its critical
temperature so that liquid can be formed at some suitable pressure, also
below the critical pressure.
Gas Critical Temperature
(oC)
Critical Pressure (atm)
NH3 132.4 113.5
CO2 31.0 73.8
He -267.96 2.27
CH4 -82.6 46.0
N2 -146.9 33.9
H2O 374.0 217.7

4. Applications of Liquefied Gases
Uses of liquid Nitrogen (N2)
 in cryotherapy for removing unsightly or potentially malignant skin lesions such as warts and
actinic keratosis
 to store cells at low temperature for laboratory work
 in cryogenics
 as a source of very dry nitrogen gas
 for the immersion, freezing, and transportation of food products
 for the cryopreservation of blood, reproductive cells (sperm and egg), and other biological
samples and materials
 to preserve tissue samples from surgical excisions for future studies
 as a method of freezing water and oil pipes in order to work on them in situations where a valve is
not available to block fluid flow to the work area, method known as "ice plug" – nowadays
replaced by electrical heat pumps (for small pipe diameters)
 to shrink-weld machinery parts together

5. Uses of liquid Oxygen (O2) (LOX)
 Liquid oxygen is a common cryogenic liquid oxidizer propellant for
spacecraft rocket applications, usually in combination with liquid
hydrogen, kerosene or methane .
 Liquid oxygen is used to create vitamin supplements.
 Liquid oxygen is also used to manufacture certain oxygen therapy
sprays. These are used topically to heal wounds, bug bites and
various skin conditions.

6. Uses of liquid carbon-dioxide (CO2)
 Carbon dioxide (CO2) is used as a key cryogenic agent in cooling,
chilling and freezing applications — protecting the taste and
texture of food products by maintaining proper temperature
control.
 Carbon dioxide is most often mixed with argon as a shielding gas
used to prevent atmospheric contamination of molten metal in
electric arc welding processes.
 A safe alternative to mineral acids, carbon dioxide replaces
chemicals used in pH reduction.

7. Liquefaction Cycles
 Some of the commonly used thermodynamic cycles for liquefaction of
gases are :
(i) Ideal liquefaction Cycle
(ii) Linde-Hampson Process
(iii) Claude Cycle
(iv) Kaptiza Cycle
(v) Heylandt Cycle
(vi) Cascade System

8. Joule-Thomson effect
 In thermodynamics, the Joule–Thomson effect describes the
temperature change of a gas or liquid when it is forced through a
valve or porous plug while kept insulated so that no heat is
exchanged with the environment. This procedure is called a
throttling process or Joule–Thomson process. At room temperature,
all gases except hydrogen, helium and neon cool upon expansion
by the Joule–Thomson process.
If J-T coefficient is +ve then a gas
cools down on expansion and if it is -ve
then the gas heats up.

9. Joule Thomson Inversion Curve

10. Maximum Inversion temperatures of
some gases
Gas Max. Inversion Temperature (oC)
Air
Carbon-Dioxide
330.15
1227
Nitrogen 347.93
Oxygen 491
Hydrogen -77.63
Neon -23
Helium -249.85
Methane 695

11. Liquefaction Cycles
 Ideal liquefaction Cycle :
It is the most basic liquefaction cycle which includes an isothermal
compression process and an isentropic process as shown in fig.

12. Linde-Hampson Process
 It was developed by William Hampson (1895) and by Carl von Linde (1895),
in which the gas was recirculated through a heat exchanger in order to
lower the temperature of incoming gas.

13. Linde–Hampson Process (Contd.)
T-s Diagram for Linde-Hampson Process
1—2 : is the isothermal compression
2—3 : is Isobaric cooling occurring in Heat Exchanger
3—4 : is isenthalpic expansion (throttling) which results
in cooling due to Joule-Thomson effect .
Finally liquid and gaseous phases are separated in
separator.

14. Claude Cycle
 Gases can also be liquefied by Claude's process in which the gas is
allowed to expand isentropically. While expanding, the gas has to do work
as it is led through an expansion turbine. Final liquefaction takes place by
isenthalpic expansion in a Joule-Thomson-Valve.

15. Claude Cycle (Contd.)
T-s diagram for Claude Cycle

16. Performance Parameters
 These are the functions which are used to indicate the performance of a
liquid system. There are mainly four process parameters :
(i) Work done per unit mass of gas compressed (W/m)
(ii) Work done per unit mass of gas liquefied (W/mf )
(iii) Yield: It is the mass of liquid gas produced per unit mass of gas
compressed .
(iv) Figure of Merit(FOM) : It is the ratio of minimum work required to the
actual work needed to liquefy the gas.

17. Aspen HYSYS
 Aspen HYSYS is a Process modeling tool for steady-state simulation design,
performance monitoring, optimization.
 Automatically integrate process models with your engineering knowledge
databases, investment analyses, production optimization and numerous
other business processes.
 System simulation is the calculation of operating variables such as pressure,
temperature, and flow rates, energy of fluids in a thermal system operating
in a steady state.
 It is generally use in chemicals, specialty chemicals, petrochemicals and
metallurgy industries.

18. Benefits of ASPEN HYSYS
 To predict the behaviour of a process using basic engineering relationships
such as mass and energy balances, phase and chemical equilibrium, and
reaction kinetics.
 With Aspen HYSYS, companies can design, simulate, troubleshoot and
manage profitable process plants.
 To avoid production delays, downtime or off-spec product, cost effective
tools.

19. Interface of ASPEN HYSYS
Simulation on ASPEN HYSYS

20. Different components used

21. Ideal Liquefaction Cycle

22. Variation of various parameters with
pressure ratio for Ideal Liquefaction
Cycle

23. Variation of various parameters with pressure ratio for Ideal Liquefaction Cycle
(contd.)

24. Variation of various parameters with pressure ratio for Ideal
Liquefaction Cycle

25. Variation of yield with
pressure ratio of compressor

26. NON-RGENERATIVE LIQUFACTION CYCLE WITH THROTTLING EXPANSION.

27. Case study 1

28. Variation with pressure ratio

29. Molar flow with cooler E101 outlet temperature

30. Linde’s Cycle with properties given at
different states

31. Properties at different points in Linde’s cycle

32. MOLAR FLOW

33. Worksheet of HEX E101 in Linde’s Cycle

34. Pressure and temperature across HEX -101 Variation of Enthalpy and Temperature across shell and tube

35. Claude’s Liquefaction Cycle

36. Properties at different points in Claude’s Cycle

37. HEX-101

38. HEX-101 : Ratings

39. Heat flow across shell and tube

40. HEX - 102

41. HEX – 102

42. HEX-103

43. HEX -103 : CHARACTERISTICS

44. CONCLUSION
 In case of ideal thermodynamic cycle, since it a non – regenerative ideal cycle, with
efficiency of 100%, so we observed that molar flow of liquefied gas increases with pressure
ratio in compressor, and it reaches 100 kg mol/h of molar flow of liquefied gas at the min
pressure of 28Gpa or 2.8*10000000 kpa , start at the pressure of 8720Kpa.
 In case of NON-RGENERATIVE LIQUFACTION CYCLE WITH THROTTLING EXPANSION,molar flow
first remains zero for the pressure ratio range ( 0 – 237 ), and it starts giving liquefied air from
the pressure ratio of 237 and then there is increase in the value of liquefy gas upto the ratio
of 342 at this ratio we get molar flow of 1.727 Kgmol/h for the inlet of 100 Kg mol/h of gas,
and after that it decreases to zero at the ratio of 498 , Since max. molar flow is 1.727Kg
mol/h which is quite low in value that is the reason, why we never use cooler as a
temperature reducing device instead of this we use heat exchanger, (efficiency of
compressor is 80%).
 In case of simple Linde’s cycle, due to the use of the heat exchanger, we can’t be able to
do case studies because it requires certain value of the flow of regenerative stream which
gains heat and provide cooling to the compressed air , so here we made a simulation in
which outlet kept fix having a value of 2 Kg mol/h for the inlet of 100Kg mol/h, with the
pressure ratio of 460, inlet temperature of 25degree C , and outlet temperature is -195
degree C, also obtain rating, design characteristics, parameters related to heat exchanger
,with value of FOM= .21.
 Finally in case of Claude cycle, same reason is there for not getting the case study, so we
need to fix its value to 40% and determine the various parameters like in Linde’s cycles for
all the 3 heat exchangers.

45. Thank You!!!.