CS218492B1 - Oxygen boiling condenser inside pipes - Google Patents

Abstract

The subject of the invention relates to a condenser of an air separation device with boiling oxygen inside the tube space. Nitrogen condenses outside the tubes. The boiling liquid and vapor mixture exits the tubes to the upper tube sheet, where the liquid phase is separated from the gaseous phase. The liquid phase returns through a return tube under the lower tube sheet. The condenser according to the invention is provided with a jacket defining a space outside the return tube, which is filled with condensed nitrogen or non-condensable gases during operation, thereby preventing the boiling of oxygen in the return tube and thus enabling the free circulation of liquid oxygen in the condenser. The invention finds application mainly in the case of a large temperature difference between the condensing nitrogen and the boiling oxygen.

Description

The present invention relates to a condenser of an air boiling device with oxygen boiling within a tubular space.

The prior art oxygen boiling condensers consist of a large number of thin-walled tubes which are welded into the tube plates. Liquid oxygen boils inside the tubes at the expense of nitrogen condensation in the inter-tube space. The resulting steam-liquid mixture emerges from the tubes above the upper tube sheet where the liquid phase is separated from the gaseous phase. The liquid phase is returned by one or more return pipes below the lower tube plate.

A common arrangement with one central return pipe is common. The return pipe must be of such dimensions that it safely transfers any liquid phase that may be above the upper tube sheet below the lower tube sheet. Since nitrogen condenses on the outer surface of the return pipe, oxygen is boiled in the return pipe. The cross-section of the return pipe must then be such that the velocity of the liquid oxygen therein is less than the rate of exit of the oxygen gas bubbles produced by boiling. This requirement also results in considerable pipe dimensions, thereby limiting the heat exchange surface of the condenser.

These drawbacks are overcome by the oxygen boiling condenser inside the tubular space according to the invention, which consists mainly of a large number of thin-walled tubes welded to the tube plates, a cylindrical casing, a return pipe and corresponding necks. it is open at the bottom and which preferably extends to the lower tube sheet at a distance of less than 500 mm.

The main advantage of the capacitor according to the invention is that it makes it possible in a simple manner to prevent the boiling of liquid oxygen in the return pipe and thus the return pipe can have a smaller cross-section and the space created can be used to install the heat exchange surface.

An exemplary condenser solution according to the invention is shown schematically in Fig. 1 and Fig. 2 a capacitor of a large-capacity air separation device.

Thousands of aluminum tubes 3 12 / 1.5 are welded into two tube plates 1, 2. The condenser is closed by vaulted bottoms 11, 12 and a cylindrical sheath 13. The liquid oxygen enters through the throat 8 and after evaporation the gaseous oxygen exits the condenser through the throat 10. The condenser enters the orifice 9 and, after condensing in the inter-tube space, exits the orifice 7. In order to prevent the boiling of oxygen in the central return pipe 5, a housing 6 is formed around it, which is open at the bottom. The distance of the sheath 4 from the lower tube sheet 2 is less than the assumed height of the condenser, i.e. liquid nitrogen, on the lower tube sheet 2.

The sheath 4 is preferably formed into a sheath of a hexagonal regular prism so that at the same time it forms a support surface for the condenser tubes 3. The sheath 4 defining the space 6 extends below the throat 7 of the condensed nitrogen evacuation. Due to this arrangement, as soon as nitrogen begins to liquefy within the inter-conduit space of the condenser, it floods the lower edge of the housing 4 and thus separates the spaces 6 from the inter-conduit space of the condenser. A lower pressure is automatically set in the space 4 because there is no nitrogen gas supply and the gas condensation on the central return pipe 5 is stopped. This also automatically stops the boiling of the liquid oxygen. The liquid oxygen flowing through the return pipe 5 below the lower tube sheet 2 does not boil and therefore the diameter of the tube may be smaller and thus there is more space for the installation of the heat exchange surface.

In another arrangement, the space 6 may extend beyond the throat 7 of the liquid nitrogen and the condensation process on the central tube is stopped gradually by the accumulation of non-condensable gases. According to another exemplary embodiment, the housing 4 may be cylindrical.

The capacitor according to the invention finds application mainly in the case of a large temperature difference between the condensing nitrogen and the boiling oxygen, since it makes it possible to significantly reduce the size of the central return pipe.

Claims (1)

OF THE INVENTION characterized in that a coaxial space (6) is formed around the return pipe (5) by the jacket (4), which is open at the bottom. pThe subject Oxygen boiling condenser inside tubes, consisting primarily of a large number of thin-walled tubes welded into tube sheets, a cylindrical shell and a return tube, 1 sheet of drawings