US 8,555,673 B2Granted

Method and device for separating a mixture of at least hydrogen, nitrogen, and carbon monoxide by cryogenic distillation

AssigneeL'Air Liquide Societe pour l'Etude et l'Exploitation des Procedes Georges Claude

InventorsArthur Darde, Antoine Hernandez

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Abstract

The invention relates to a method and apparatus for separating a mixture containing carbon monoxide, nitrogen and hydrogen by cryogenic distillation in a separation system which includes a denitrification column and at least another column. The method can include separating the mixture in order to obtain a fluid enriched with carbon monoxide and containing nitrogen, separating the fluid in the denitrification column, pressurizing the carbon monoxide flow from the column in a compressor up to a high pressure, collecting a fraction of carbon monoxide flow to be used as a product, expanding an amount of the high-pressure carbon monoxide flow in a valve prior to supplying it to the denitrification column, and varying the flow expanded in the valve according to re-boiling needs of the denitrification column.

Claims11

Dependent claims

A method for separating a mixture of carbon monoxide, nitrogen, hydrogen and optionally methane by cryogenic distillation in a system of separation means wherein the system includes a turbine, a valve, a methane scrubbing column, a stripping column, a CO/CH4 column, and a denitrogenation column having a top, bottom, and a reboiler, the reboiler having reboiling needs, wherein the denitrogenation column is disposed upstream or downstream the CO/CH4 column, wherein the valve is disposed upstream the denitrogenation column, the method comprising the steps of;

a) removing hydrogen and optionally methane from said mixture of carbon monoxide, nitrogen, hydrogen and optionally methane, thereby producing a fluid enriched in carbon monoxide and containing nitrogen;
b) removing nitrogen from said fluid enriched in carbon monoxide and containing nitrogen in said denitrogenation column, thereby producing a carbon monoxide rich fluid;
c) compressing at least a portion of said carbon monoxide rich fluid in a compressor, thereby producing a high-pressure carbon monoxide stream;
d) collecting at least a first fraction of said high-pressure carbon monoxide stream as product;
e) cooling a second fraction of said high-pressure carbon monoxide stream;
f) introducing a third fraction of said high-pressure carbon monoxide stream to said turbine and from said turbine to the bottom of said denitrogenation column for further separation;
g) expanding a first portion of said second fraction of the high-pressure carbon monoxide stream using the valve before sending to the bottom of said denitrogenation column for further separation;
and
h) introducing a second portion of the second fraction of the high-pressure carbon monoxide stream to a bottom eboiler of said stripping column and/or of said CO/CH4 column,
i) varying the flow of the first portion of said second fraction of the high-pressure carbon monoxide stream across the valve as a function of the reboiling needs of the reboiler of said denitrogenation column.

7 more elements

An installation for separating a mixture of carbon monoxide, nitrogen, hydrogen and optionally methane by cryogenic distillation in a system of separation means comprising a turbine, a methane scrubbing column, a stripping column, a CO/CH4column, and a denitrogenation column, the denitrogenation column being downstream or upstream of the CO/CH4 column, the denitrogenation column having a top, a bottom, and a reboiler, the reboiler having reboiling needs, wherein the installation further comprises:

means for sending the mixture to the system of separation means in order to obtain a fluid enriched in carbon monoxide and containing nitrogen;
means for sending said fluid enriched in carbon monoxide and containing nitrogen into the denitrogenation column;
a compressor;
means for sending a flow of carbon monoxide that originates from the system of separation means to the compressor, the compressor being operable to create a high-pressure carbon monoxide stream;
means for collecting a first fraction of the high-pressure carbon monoxide stream as a product;
means for sending a third fraction of the high-pressure carbon monoxide stream to the turbine and from the turbine to the denitrogenation column for further separation;
means for sending a second portion of a second fraction of the high-pressure carbon monoxide stream to a bottom reboiler of the stripping column and/or of the CO/CH4 column;
a heat exchanger configured to provide heat exchange for the installation;
means for sending a first portion of the second fraction of the high-pressure carbon monoxide stream to an expansion valve and then to the bottom of the denitrogenation column for further separation, the expansion valve configured to lower the pressure of the first portion of the second fraction of the high-pressure carbon monoxide stream to have the same pressure as the denitrogenation column;
means for varying the flow of the first portion of the second fraction of the high-pressure carbon monoxide stream expanded in the valve as a function of the reboiling needs of the reboiler of the denitrogenation column.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/519,990Filed 12 Dec 2007
Priority: FR 06 5577021 Dec 2006
Published: US 2010/0071411 A125 Mar 2010
Granted: 15 Oct 2013
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

F25J 3/0223
Characterised by the feed stream: h2/CO mixtures, i.e. synthesis gas; Water gas or shifted synthesis gas
F25J 3/0252
Characterised by the separated product stream: separation of hydrogen
F25J 3/0257
Characterised by the separated product stream: separation of nitrogen
F25J 3/0261
Characterised by the separated product stream: separation of carbon monoxide