FR91762E - - Google Patents

Description

FRENCH REPUBLIC

1HE ADDITION

MINISTRY OF INDUSTRY FOR THE PATENT OF INVENTION

No. 1.516.728

P.y. No. 52.264 International Classification

N ° 91.762 F 25 days

INDUSTRIAL PROPERTY SERVICE

Method and apparatus for cooling and low temperature liquefaction of gas mixtures.

FRENCH STUDIES AND CONSTRUCTION COMPANY TECHNIP residing in France (Hauts-de-Seine).

(Main patent issued on March 31, 1965.)

Requested on March 5, 1966, at 10:15 a.m., by mail.

Issued by decree of July 1, 1968.

{Official Bulletin of Industrial Property, No. 32 of August 9, 1968.)

{Certificate of addition the issue of which has been postponed pursuant to article 11, § 7, of the law of 5 July 1844 amended by the law of 7 April 1902.)

The main patent describes a method and apparatus for cooling and liquefying gas mixtures at low temperature.

It is indicated in this patent that the refrigeration circuits for cooling and condensing the gas to be liquefied on the one hand, and for condensing the condensates of the refrigerant on the other hand, can operate at the same pressure or at different pressures. In a practical example, a pressure of 3.5 to 4 bars is mentioned for the second circuit and 1.5 to 2 bars for the first circuit.

The purpose of this addition is to specify the operating pressures of these circuits.

It was observed that it was important to implement a lower pressure in the first circuit than in the second circuit, the pressures having to be chosen between 0.4 and 3 atmospheres, preferably between 1 and 1.5 atmospheres for the first circuit, between 4 and 8 atmospheres, preferably between 5 and 7 atmospheres for the second circuit.

Thanks to this arrangement, the energy consumption is significantly reduced compared to what it was in the liquefaction systems prior to that described in the main patent and the present addition.

On the other hand, the heat losses are reduced because the liquefaction of the refrigerant can be obtained at relatively high temperatures.

Finally, this pressure difference makes it possible to use a refrigerant with a low nitrogen content.

8 210548 7 ♦

or other very low boiling gas. However, the liquefaction of such a fluid requires less expenditure of energy.

On the other hand, it was found, and this constitutes a variant of the process of the main patent, that the refrigerant fluid could take the following composition:

Nitrogen and more volatile (eg helium): from 0 to 3% by volume;

Methane: from 20 to 32% by volume;

Ethane: from 34 to 44% by volume;

Propane: 12 to 20% by volume;

Butanes: 8 to 15% by volume;

Pentanes and heavier: from 3 to 8% by volume.

The refrigerant, the composition of which is given above, can be used practically in all cases of liquefying a natural gas containing methane as the main constituent. With this fluid the energy consumption is reduced to a minimum.

The pressures indicated in this patent are absolute pressures.

ABSTRACT

The purpose of this addition is to specify the preferred conditions for using the method and device of the main patent:

at. A lower refrigerant vaporization pressure is used in the cooling and condensing system of the gas to be liquefied than in the refrigerant condensate preparation system, the pressure advantageously being between 0.1 and 3 atmospheres in the first system. , preferably between 1 and 1.5 atm.

Claims (11)

[91.762 / 1.516.728] - spheres, and between 4 and 8 atmospheres in the second system, preferably between 5 and 7 atmospheres. b. The refrigerant has the following volumetric composition: Nitrogen and more volatile: from 0 to 3 fé: Methane: from 20 to 32%; Ethane: 34 to 44%; Propane: 12 to 20%; Butanes: 8 to 15%; Pentanes and heavier: from 3 to 8%. FRENCH STUDIES AND CONSTRUCTION COMPANY TECHNIP For the * reat * of the fascicles, contact the National Imphimehie, 27, rue de l'Ia Convention, Paris (15 *).