Method and installation for separating air by cryogenic distillation
AssigneeL'Air Liquide, Societe Anonyme pour I'Etude et I'Exploitation des Procedes Georges Claude
InventorsFrederic Bonne, Nicolas Foirien, Alain Guillard
Life of this patent
Estimating the term…
Abstract
An installation for separating air by cryogenic distillation comprises a compressor, a heat-exchange line, a system of columns, an electric motor for driving the compressor, a pipe for taking off a liquid from the system of columns, a pump for pressurising the liquid drawn off and means for affording an exchange of heat between the air compressed by the compressor and the liquid pressurised by the pump and means for reducing the output pressure of the pump according to the frequency of the electricity supplying the electric motor.
Claims17
1-15. (canceled)
A method of separating air by cryogenic distillation, the method comprising the steps of:
- i) compressing a flow of air in a compressor, cooling said flow of air in a heat-exchange line, and then sending said flow of air to a system of columns where the flow of air separates in order to form a nitrogen-enriched flow and an oxygen-enriched flow;
- ii) driving the compressor by a motor supplied by electricity having a first frequency;
- iii) withdrawing a liquid flow from the system of columns, pressurizing said liquid flow to a first pressure by a pump and either vaporizing said liquid flow by indirect heat exchange with the flow of air coming from the compressor to produce a gaseous product substantially at the first pressure, or, in the case of an oxygen-rich liquid flow, sending the oxygen-rich liquid flow at the first pressure to the top of an auxiliary column supplied at the bottom by the flow of air coming from the compressor, withdrawing gaseous oxygen from the top of the auxiliary column as a product, and sending an intermediate liquid from the auxiliary column to the system of columns,
- wherein if the frequency of the electricity passes below a given threshold below the first frequency, the pressurization pressure of the liquid flow is reduced to a second pressure lower than the first pressure.
An installation for separating air by cryogenic distillation, the installation comprising a compressor, a heat-exchange line, a system of columns, an electric motor configured to drive the compressor, a pipe configured to draw off liquid from the system of columns, a pump configured to pressurize the liquid drawn off and means for affording a direct or indirect exchange of heat between the air compressed by the compressor and the pressurized liquid, and means for regulating the pressure of the liquid pressurized in the pump as a function of the frequency of the electricity supplying the electric motor.
Dependencies are inferred from the claim text.