24/06/2005 - Controller General of Patents, Designs, and Trade Marks

(21) Application No. 954/DEL/1999 A (22) Date of filing of Application: 08/07/1999
(54) Title of the invention: “A METHOD AND APPARATUS FOR CARRYING OUT CRYOGENIC
AIR SEPARATION .”
(51) International Classification 7 : F 25J 3/04
(30) Priority Data :
(31) Document No.: NA
(32) Date : NA
(33) Name of convention country : NA
(66) Filed U/s 5(2) : NIL
(61) Patent of addition to application No. : NA
(62) Filed on : NA
(63) Divisional to Application No. :NIL
(64) Filed on : NA
Total No. of Pages:16
(57) Abstract:
(71) Name of the applicant:
PRAXAIR TECHNOLOGY, INC.
Address of the Applicant:
39 Old Ridgebury Road, Danbury, State
of Connecticut 06810-5113, United
States of America.
(72) Name of the Inventor:
DANTE PATRICK BONAQUIST
NANCY JEAN LYNCH
A method for carrying out cryogenic air separation comprising:
(A) passing a first portion (67) of the feed air (60) for a cryogenic air separation plant (10, 11) through
a primary heat exchanger (1) and thereafter passing the first feed air portion (70) into the cryogenic
air separation plant (10);
(B) compressing a second portion (66) of the feed air (60) for the cryogenic air separation plant (10, 11)
to a high pressure and passing at least some stream of feed air portion (64) of the high pressure
second feed air portion (68) as input to a high ratio turboexpander (32) without passing through any
portion of the primary heat exchanger, wherein the pressure of the gas input to said high ratio
turboexpander is at least 15 times the pressure of the gas output from said high ratio turboexpander;
(C) turboexpanding the high ratio turboexpander input (64) through the high ratio turboexpander (32)
and passing the resulting turboexpanded output (82, 83) into the cryogenic air separation plant (11);
(D) separating the feed air (70, 72, 83) within the cryogenic air separation plant (10, 11) by cryogenic
rectification to produce at least one of product oxygen (76, 84) and product nitrogen (91, 93); and
(E) recovering at least one of product oxygen (84) and product nitrogen (93) from the cryogenic air
separation plant (10, 11);
characterized in that
in step (C) the resulting turboexpanded output (82, 83) is passed into the cryogenic air separation plant
(11) without passing through any portion of the primary heat exchanger (1).
18211