6. Liquefaction of gases cannot be done by
(A) Exchange of heat with colder stream
(B) Adiabatic expansion through a throttle valve (Joule-Thomson expansion)
(C) Merely compressing it beyond critical pressure
(D) Adiabatic expansion against a piston or in a turbine
(A) Exchange of heat with colder stream
(B) Adiabatic expansion through a throttle valve (Joule-Thomson expansion)
(C) Merely compressing it beyond critical pressure
(D) Adiabatic expansion against a piston or in a turbine