RU2500452C2 - Rectifier tower with bubble-cap trays - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to mass-and-heat exchange hardware, particularly, to rectifiers and absorbers and may be used in petrochemical and chemical, oil and gas industries. Proposed rectifier tower comprises body with process unions, trays with vapor and overflow branch pipes, and height-adjustable bubble-cap trays. Horizontal edges of cap cutouts are equipped with vanes arranged radially outside in horizontal plane.

EFFECT: higher efficiency of mass exchange.

3 dwg

Description

The invention relates to mass transfer equipment in the field of processing hydrocarbon raw materials, chemical and food products, in particular to devices for rectification, absorption of petroleum products, chemical and food products by separating products by boiling points during mass transfer between liquid and vapor (gas), and can find application in oil refining, chemical, petrochemical, gas, food industries.

Known distillation columns with cap plates used for mass transfer processes for liquid-vapor systems described in books: A.G. Kasatkin, “The main processes of technical technology”, M. Chemistry, 1971, p. 452. [1], D.A. Baranov, A.M. Kutepov “Processes and Apparatuses”, M Academy 2005, p.182, 183 [2].

These columns have a housing, mass transfer multi-cap plates with steam nozzles, caps with serrated edges or arched slots and drain nozzles.

Mentioned columns with caps of known designs are not effective enough from the point of view of the mass transfer process itself when separating the mixture into a liquid and vapor phase. This is due to the limited total value of the edges of the slots of the caps through which the bubbling of vapors occurs along the length of the mixture path and, accordingly, the contact time of the vapor with the liquid. Known cap designs do not allow to increase the total length of the mentioned edges and the contact time of the vapor with the liquid, i.e. increase the time and surface of the interphase contact, which directly depends on the length of the edges, the slots of the caps through which the vapor fraction is bubbled.

Known [3] mass transfer plate with perforation in the side walls of the steam cap is made in the form of arched slots convex outward with inlet openings directed at an acute angle to the vertical down to the same side opposite to the location of the drain pipe on the plate, and between the walls of the column to the walls the steam cap is tightly diametrically mounted vertical partition extending in width to the opposite side wall of the steam cap. This design of the cap of the mass transfer plate with arched slots convex outward with an acute angle to the vertical downwards is designed to direct the vapor-liquid flow, and not to increase the interface surface (RU 94020203 A1, 04/27/1996).

OST 26 291-94 “Welded steel vessels and apparatus, general technical conditions, M NPO OBT 2006 p. 101 [4] describes cap plates, where it is indicated that caps should be made in accordance with GOST 9634 [5]. In the lower part of such caps there are vertical slits of a rectangular or trapezoidal shape.

The column with caps according to GOST 9634, as the closest in technical essence to the proposed device, is adopted as a prototype.

However, the prototype, in which the design of its caps does not allow to increase the path length of the mixture and to develop the phase contact surface, determined by the number and shape of the slots and, accordingly, increase the efficiency of the low-exchange process.

The aim of the invention is the elimination of this drawback and increase the efficiency of the distillation column. The problem is solved due to the fact that the horizontal edges of the slots of the caps are equipped with blades placed on the outside of the caps radially and in a horizontal plane.

As a result of this technical solution, the vapor-liquid mixture, coming out from under the cap, passes a certain path under the said blades located at the boundary of the vapor and liquid media, it sparges into the liquid outside the cap around the entire perimeter of the edges of each blade. This perimeter of the blade is greater than the length of the horizontal edge of the slot in the prototype, as a result of which the path length and the phase contact surface are increased, which is the main factor in increasing the efficiency of the oil exchange process in the distillation column as a whole.

As an example, consider the case when the edge length is, for example, 1 cm, and the blade is square with side length also 1 cm. In this case, the three sides of each blade are the edges through which steam is barbated, and their total length is 3 cm, those. three times the length of the edge of the slot in the prototype. At the same time, the path length of the mixture under the blade increases and, accordingly, the contact time of the mixture

Figure 1 schematically shows a longitudinal section of a column;

Figure 2 is a view A on an enlarged scale;

Figure 3 is a transverse section bB of the cap with the blades.

The proposed distillation column consists of a housing 1, a nozzle 2 for the entrance of the vapor-liquid mixture, a nozzle 3 for the exit of the liquid (heavy fraction) and a nozzle 4 for the exit of the vapor (light fraction). In addition, the column contains plates 5 with steam nozzles 6 and overflow devices 7, as well as caps 8 with vertical slots 9 provided with blades 10, which are made along the width of the slots in the cap and are located on the outside of the latter radially and in a horizontal plane.

The proposed column operates as follows. The initial vapor-liquid mixture is fed into the column through the nozzle 2. Vapors through the nozzles 6 enter the cavity of the caps 8, displace the liquid from them to the upper edge of the slots 9 and, accordingly, the blades 10, after which the steam mixture, having passed a certain path under the blade, begins to sparge a layer of liquid outside the caps 8. The heavy fraction condenses in this liquid and through the overflow nozzles 7 enters the underlying plate, and the vapor enters the overlying plate through the corresponding steam nozzles, where the separation process I'm going on. Since the blades 10 are located at the interface between the media (vapor and liquid fractions), the vapor-liquid mixture passes under the blades 10 along an elongated path and sparges into the liquid layer on the plate along the entire perimeter of the blades, and since this perimeter significantly exceeds the total length of the horizontal edges of the slots, as as shown in the example above, the phase contact surface increases accordingly, the residence time of the mixture under the blade and the efficiency of the mass transfer process increases.

Claims (1)

Distillation column, including a housing with technological fittings, plates with steam nozzles and overflow devices, as well as caps with vertical slots, characterized in that the horizontal edges of the slots of the caps are equipped with blades located on the outside of the caps radially and in a horizontal plane.

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