Air separation process using cryogenic distillation
Abstract
[ 4 Q air π K ( P P 0 ) 0.35 ] 1 / 2 ( I ) In a process for the separation of air into at least one constituent by cryogenic distillation of air in a system of columns ( 1, 3 ) comprising at least one column ( 1, 3 ) for producing at least gaseous oxygen and/or nitrogen as product, if the operating pressure of the largest-diameter column is P>2 bar abs, then the diameter (in metres) of this column is less than (I), where : Q air is the sum of the flow rates in Sm 3 /h of the air feeding the column system and K is the capacity per unit area of the column and P 0 is equal to 2 bar abs.
Claims
exact text as granted — not AI-modified1 . Process for the separation of air into at least 5. one constituent by cryogenic distillation of air in a system of columns ( 1 , 3 ) comprising at least one column ( 1 , 3 )
a) for producing at least gaseous oxygen as product, such that the oxygen yield is greater than 90% (preferably 95%) and the oxygen purity is greater than 90 mol % oxygen (preferably 95 mol % oxygen or even 99 mol % oxygen) and/or b) for producing at least nitrogen such that the nitrogen yield is greater than 85% (preferably greater than 90%) and the nitrogen purity is greater than 99 mol % nitrogen (preferably 99.99 mol % nitrogen or even 99.999 mol % nitrogen) characterized in that:
if the operating pressure of the largest-diameter column ( 3 ) is P<2 bar abs, then the diameter (in metres) of this column is less than:
(
4
Q
air
π
K
)
1
/
2
if the operating pressure of the largest-diameter column is P>2 bar abs, then the diameter (in metres) of this column is less than:
[
4
Q
air
π
K
(
P
P
0
)
0.35
]
1
/
2
where:
Q air is the sum of the flow rates in Sm 3 /h of the air feeding the column system;
K is the capacity per unit area of the column and equals at least 21000 Sm 3 /m 2 (preferably at least 23000 Sm 3 /m 2 or even at least 25000 Sm 3 /m 2 ); and
P 0 is equal to 2 bar abs.
2 . Process according to claim 1 , in which the largest-diameter column ( 3 ) of the column system contains at least one section ( 2 ) filled with a gas/liquid contactor allowing material exchange between the gaseous phase and the liquid phase such that its effectiveness is defined by a TUH (Transfer Unit Height) of less than 350 mm (preferably less than 300 mm).
3 . Process according to claim 2 , in which the gas/liquid contactor is composed of cross-corrugated structured packings having a density of less than 500 m 2 /m 3 , preferably less than 400 m 2 /m 3 .
4 . Process according to claim 1 , 2 or 3 , in which the column system comprises at least one double column formed by a medium-pressure column ( 3 ) and a low-pressure column ( 1 ), the medium-pressure column being thermally coupled to the low-pressure column, and the low-pressure column constituting the largest-diameter column.
5 . Process according to claim 4 , producing oxygen in which the ratio of the oxygen produced to the cross section of the low-pressure column is greater than or equal to 150 t/d/m 2 .
6 . Process according to claim 4 or 5 , in which the ratio of the flow rate of air sent to the column system to the cross section of the low-pressure column is not less than 21000 Sm 3 /h/m 2 , preferably not less than 23000 Sm 3 /h/m 2 and even more preferably not less than 25000 Sm 3 /h/m 2 .
7 . Process according to claim 4 , 5 or 6 , in which the ratio of the gaseous air sent to the medium-pressure column ( 1 ) to the cross section of the low-pressure column is not less than 18000 Sm 3 /h/m 2 (preferably not less than 20000 Sm 3 /h/m 2 and even more preferably not less than 22000 Sm 3 /h/m 2 ).
8 . Process according to claim 7 , in which at least one section ( 2 ) of the medium-pressure column ( 1 ) contains cross-corrugated structured packings with a density not exceeding 500 m 2 /m 3 , or even 400 m 2 /m 3 .
9 . Air separation unit using cryogenic distillation, comprising a column system, the diameter of the largest-diameter column ( 3 ) being between 3 and 6 m, the largest-diameter column containing at least one gas/liquid contactor section ( 2 ) consisting of cross-corrugated structured packings having a density not exceeding 500 m 2 /m 3 , or even 400 m 2 /m 3 .Join the waitlist — get patent alerts
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