RU2384800C1 - Contact heat exchanger - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: invention is intended for heat exchange and is to find application in steam generators. Heat exchanger consists of external column formed with cylindrical housing, the edges of which are restricted with a cover and a bottom, internal column, external tube connecting the bottom and the housing of external column to each other and interconnected through the holes to the bottom of cavity of working chamber, water supply pipeline passing through the cover of external column, steam outlet pipeline installed on the cover of external chamber and interconnected through the hole made in it to the top of working chamber, and heater located on external tube. Bottom of the cavity of working chamber is filled with liquid metal heat carrier. Free end of water supply pipeline and free edge of internal column are located below the level of liquid metal heat carrier. Heat exchanger is equipped with an inlet device consisting of vertical cylindrical housing and cover installed in its upper part. Inlet device is located under the level of liquid metal heat carrier. Perforation is made in the lower part of the inlet device housing. One of water supply pipeline ends is interconnected with the inlet device cavity through its cover.

EFFECT: invention provides stationary operation of contact heat exchanger and decreases formation of deposits in it.

2 cl, 1 dwg

Description

The invention relates to heat exchangers and can be used in steam generators and desalination plants in the production of water vapor and fresh water.

Known contact heat exchanger [USSR Copyright Certificate for the invention No. 1495621. Contact heat exchanger for two immiscible liquids. Publ. 07/23/1989. Bull. No. 27]. In the contact heat exchanger inside the housing there is a switchgear of the heated fluid. The housing is equipped with nozzles for supplying and discharging heating and heated fluid. The housing contains a cylindrical shell with an inlet section and a confuser outlet section, coaxially mounted inside the housing and connected to the heating fluid supply nozzles, brought into the cavity of the shell with downward inclined ends. The distribution device is located in the inlet section, and the heating fluid outlet pipes are located in the upper part of the housing above its supply pipes.

A disadvantage of the known device is that the switchgear of the heated fluid is in contact with the heating fluid. In this case, the possibility of boiling of the heated fluid inside the switchgear is not excluded, which can lead to a sharp increase in pressure in it and disruption of the heat exchanger.

The closest in technical essence to the claimed device is a direct contact steam generator [I.Kinoshita, Y. Nishi. Heat Transfer Characteristics of a Direct Contact Stream Generator with Low Melting point Allow and Water. 10th International Heat Transfer Conference, 1994, Volume 3, paper 5 - NR - 13/14 - 18 August, 1994, Brighton, UK].

The direct contact steam generator consists of a working chamber made in the form of two coaxially installed columns, a double-walled pipeline for supplying water to the volume of the liquid metal coolant, a circulation loop of the liquid metal coolant, a heater, and a steam pipe.

The disadvantages of the known device are:

- the possibility of a very sharp boiling of water in the volume of the coolant, a sharp increase in pressure in the pipeline and the cessation of water supply;

- the formation of deposits on the inner and outer surfaces of the pipeline due to non-isothermal mass transfer from the hot coolant to the cold sections of the pipeline, partial or complete blockage of the water supply channel and the malfunction of the steam generator.

The proposed technical solution allows to eliminate these drawbacks, namely, it prevents boiling of water before it is introduced into the volume of the liquid metal coolant and the formation of deposits on the surfaces of the water supply pipe into the volume of the coolant due to non-isothermal mass transfer.

To eliminate these shortcomings in a contact heat exchanger consisting of an external column formed by a cylindrical body, the ends of which are limited by a cover and a bottom, an internal column in the form of a cylindrical shell located on the bottom of the external column, an outer pipe connecting the bottom and the body of the external column and communicated through openings with the lower part of the cavity of the working chamber, the water supply pipe passing through the cover of the external column, the steam exhaust pipe mounted on the cover of the external onny and communicated through the aperture therein with the upper portion of the working chamber, and a heater disposed on the outer tube, the lower part of the container cavity is filled with liquid metal coolant, the free end of the water supply conduit and the free end of the inner column disposed below the liquid metal coolant, has:

- the contact heat exchanger is additionally equipped with an inlet device consisting of a vertically oriented cylindrical body and a cover mounted in its upper part;

- place the inlet device under the level of the liquid metal coolant;

- perform perforation in the lower part of the inlet housing;

- inform one of the ends of the water supply pipe with the cavity of the inlet device through its cover.

In the particular case of the contact heat exchanger, it is proposed to perforate the lower part of the inlet housing in the form of a system of vertically oriented slots.

The technical result of the proposed technical solution is to ensure the stationary operation of the contact heat exchanger and reduce the formation of deposits in it.

The longitudinal axial section of the contact heat exchanger is shown in the drawing. The following notation is used in the drawing: 1 - inner column; 2 - the bottom of the outer column; 3 - the body of the outer column; 4 - inlet housing; 5 - cover of the outer column; 6 - inlet cover; 7 - heater; 8 - outer pipe; 9 - perforation; 10 - working chamber; 11 - steam exhaust pipe; 12 - water supply pipe.

Contact heat exchanger consists of an external and an internal 1 columns, an external pipe 8, a water supply pipe 12, a steam exhaust pipe 11, a heater 7, and an inlet device.

The outer column is formed by a cylindrical body 3, the ends of which are limited by the cover 5 and the bottom 2.

The inner column 1 in the form of a cylindrical shell is located on the bottom 2 of the outer column.

The outer pipe connects the bottom 2 and the casing 3 of the outer column to each other and is communicated through openings with the lower part of the cavity of the working chamber 10.

The water supply pipe 12 passes through the cover of the outer column 5.

The steam exhaust pipe 11 is installed on the cover 5 of the outer column and communicated through an opening in it with the upper part of the working chamber 10.

The heater 7 is located on the outer pipe 8.

The lower part of the cavity of the working chamber 10 is filled with a liquid metal coolant.

The free end of the water supply pipe 12 and the free end of the inner column 1 are located below the level of the liquid metal coolant.

The inlet device consists of a vertically oriented cylindrical body 4 and a cover 6 mounted in its upper part.

The inlet device is located below the level of the liquid metal coolant.

Perforation 9 is made in the lower part of the housing 4 of the inlet device. In the particular case of the inlet device, the perforation 9 is made in the form of a system of vertically oriented slots. The presence of perforations 9 in the lower part of the housing 4 of the inlet device allows you to split the steam-water mixture stream leaving the cavity of the inlet device into separate jets (parts).

Steam-water mixture with low thermal conductivity, located in the cavity of the inlet device at its cover 6, prevents contact of the liquid metal coolant with the water supply pipe 11 and, thereby, eliminates steam explosions that occur when water is supplied into the hot liquid metal coolant, and prevents slagging of the outlet part of the supply pipe water 12.

One of the ends of the water supply pipe 12 is in communication with the cavity of the inlet device through its cover 6.

During operation of the contact heat exchanger, the upper part of the cavity of the working chamber 10 is always filled with steam.

Contact heat exchanger operates as follows.

Water through the water supply pipe 11 and an inlet connected to it is supplied under the level of the liquid metal coolant into the cavity of the inner column 1. In the cavity of the inner column 1, the water is heated, evaporates, floats in the form of steam bubbles and is separated on the free surface of the liquid metal coolant to the upper part of the working cavity chambers 10. In this case, the effect of gas lift arises, prompting along the way a couple of the movement of the liquid metal coolant. Heating and evaporation of water in the inner column 1 is accompanied by cooling and overflow of the liquid metal coolant into the annular gap formed by the outer and inner 1 columns, and then its movement in the outer pipe 8. After heating the liquid metal coolant, it again enters the cavity of the inner column 1 and interacts with water, poured under the level of the liquid metal coolant in the cavity of the inner column 4. Separating in the upper part of the cavity of the working chamber 10 water vapor is removed from it through steam exhaust pipe 11.

A specific example of a contact heat exchanger

Design characteristics of a contact heat exchanger:

External column: hull height 3 - 1,282 m; the inner diameter of the casing 3 is 0.198 m, the material is stainless steel 12XH10T.

Inner column: outer diameter - 0.121 m; inner diameter - 0.115 m; height - 0.403 m; material - stainless steel 12XH10T,

Steam exhaust pipe 11: inner diameter - 0.016 m; material - stainless steel 12XH10T.

Water supply pipeline 12: execution - “pipe in pipe”; material - stainless steel 12XH10T; the outer diameter of the outer tube is 0.016 m; the inner diameter of the outer tube is 0.012 m; the outer diameter of the inner tube is 0.006 m; the inner diameter of the inner tube is 0.003 m; thermal insulation between the inner and outer tubes - vermiculite.

Liquid metal coolant (ЖМТ): level height - 0.420 m; type of heat carrier - Pb-Bi alloy; temperature - 540 K, volumetric flow rate - 0.0001 m ³ / s.

Water: temperature - 300 K, mass flow rate - 0.002 kg / s.

Generated water vapor: temperature - 470 K.

Intake device: inner diameter of the housing 4 - 0.03 m; the outer diameter of the housing 4 is 0.027 m; case height 4 - 0.033 m; the number of slots - 16 pcs., the height of the slots - 0,015 m; the width of the slots is 0.001 m; material - stainless steel 12XH10T.

Heater 7: type - electric heater with a power of 10 kW.

Claims (2)

1. Contact heat exchanger, consisting of an external column formed by a cylindrical body, the ends of which are limited by a lid and a bottom, an internal column in the form of a cylindrical shell located on the bottom of the external column, an outer pipe connecting the bottom and the body of the external column and communicated through openings with the lower part of the cavity of the working chamber, the water supply pipe passing through the cover of the external column, the steam exhaust pipe installed on the cover of the external column and communicated through an opening in with the upper part of the working chamber, and the heater located on the outer pipe, the lower part of the cavity of the working chamber being filled with a liquid metal coolant, the free end of the water supply pipe and the free end of the inner column are located below the level of the liquid metal coolant, characterized in that the contact heat exchanger is additionally equipped with an inlet a device consisting of a vertically oriented cylindrical body and a cover mounted in its upper part, the intake device your is located below the level of the liquid metal coolant, perforation is made in the lower part of the inlet housing, and one of the ends of the water supply pipe is in communication with the cavity of the inlet device through its cover. 2. The contact heat exchanger according to claim 1, characterized in that the perforation of the lower part of the inlet housing is made in the form of a system of vertically oriented slots.