RU2197312C2 - Forced-circulation evaporator - Google Patents

Abstract

FIELD: chemical industry; power engineering and allied industries. SUBSTANCE: proposed evaporator has housing, heating chamber, branch pipes for delivery and discharge of starting liquid, vapor and heat-transfer agent. Additional horizontal heating disk mounted in parallel with bottom divides starting liquid into two parts; upper and lower parts are subjected to forced circulation by preheated air; lower part is located between two heating surfaces. Evaporator is provided with unit for cleaning the heating surfaces and removing sediment. EFFECT: increased productivity and service life. 4 dwg

Description

 The invention relates to evaporators and can be used in the chemical, energy and related industries for the evaporation of contaminated liquids with heat through heat-exchange surfaces.

 A known evaporator containing a vertical housing, a heating chamber and tubular heat exchange elements installed in it, the lower ends of which are fixed in the distribution chamber and have openings for introducing gas (steam) (A.S. 560623, MKI B 01D 1/12).

 However, in this evaporator, the heating chamber has long heat-exchange elements, which greatly complicates the circulation of the product, creates hydraulic resistance at the product inlet to the heat-exchange elements and reduces the intensity of the evaporation process.

 Known evaporation apparatus containing a vertical body with a bottom made in the form of a truncated cone, a main heating chamber installed under the bottom, an additional heating element mounted parallel to the bottom and at a certain distance from it, a device mounted on the bottom for cleaning the heating surface and removing sediment in the form one or more scrapers mounted on the shaft, nozzles for introducing a solution, for removing one stripped off product, for removing steam, for entering and leaving a coolant (US Patent 3456708, MKI B 01 D 1/30 - prototype).

 However, this apparatus uses only one side of a horizontal heating disk, which reduces the intensity and productivity of the evaporation process.

 The invention is aimed at solving the problem of increasing productivity and intensifying the evaporation process, ensuring the removal of sediment and the implementation of effective circulation of the original liquid. This is achieved by the fact that the additional heating element is made in the form of a horizontal disk, the shaft is hollow and its internal cavity forms a pipe for outputting one stripped off product, and an air heater is installed on the steam output pipe, which is connected via pipelines to the fan and one or more ducts located tangentially vertical casing.

 The invention is illustrated by drawings, where Fig. 1 shows an evaporator with forced circulation, general view (section); figure 2 - horizontal heating disk, section; figure 3 is a section aa in figure 1; figure 4 - diagram of the air supply inside the housing of the evaporator, top view.

 The evaporator with forced circulation contains a vertical housing 1, a cover 2, a bottom 3. Under the bottom 3 is the main heating chamber 4. The bottom is made in the form of a truncated cone and has a flat heating surface.

 Inside the vertical casing 1, an additional horizontal heating element 5 is installed in the form of a disk (horizontal heating disk 5), it is located parallel to the bottom 3 and at a certain distance from it. The horizontal heating disk 5 is mounted on the brackets 6. This arrangement of the horizontal heating disk 5 ensures the separation of the source liquid into two parts - lower and upper. The coolant enters the internal cavity 7 of the horizontal heating disk 5. The pipe 8 is respectively intended for input, and the pipe 9 is for the output of the coolant. On the horizontal heating disk 5 there are openings (tubes) 10, which are designed to circulate the initial fluid from the lower to the upper, and vice versa.

 A device 11 is mounted on the bottom 3 for cleaning the heating surface and removing sludge, which is made in the form of one or more scrapers 12 fixed to the hollow shaft 13. The scraper 12 is in contact with the heating surface and rotates by means of a drive. The internal cavity of the shaft 13 serves as a pipe 14 for the withdrawal of sediment and one stripped off liquid.

 A nozzle 15 is made on the lid 2 for discharging steam and air (steam-air mixture), on which an air heater 16 is installed. A fan 17 supplies air to the air heater 16, and the heated air is directed through one or more air ducts 18, mounted tangentially to the vertical casing 1, into it.

 The pipe 19 is designed to supply the source fluid (solution, product) inside the vertical housing 1.

 The evaporator operates as follows.

 Through the pipe 19 in the internal cavity of the vertical housing 1 is fed the original fluid. The coolant enters the main heating chamber 4 and the additional horizontal heating disk 5. The use of an additional horizontal heating disk 5 significantly increases the surface area of heat transfer and more intense heat transfer occurs.

 The fan 17 supplies air to the air heater 16, and the heated air through the duct 18 enters the vertical housing 1. In this case, a rotational movement of air is created in the internal cavity of the housing located above the original liquid, which, acting on the liquid, causes it to circulate intensively. Moreover, the upper and lower parts of the initial liquid are circulated.

 The lower part of the initial liquid is located between two heating surfaces - on the one hand, this is the bottom 3 and the main heating chamber 4, and on the other, the lower plane of the horizontal heating disk 5. Heating of the initial liquid in this part leads to its intensive circulation through openings 10.

 The vapor with the air rises and through the pipe 15 enters the air heater 16. The cooled vapor-air mixture is released into the atmosphere. Heated air enters the vertical housing 1.

 If necessary, the source liquid is added through the pipe 19 to the apparatus.

 The drive of the device 11 for cleaning the heating surface and removing sediment is periodically turned on. The scraper 12 makes one revolution, cleaning the heating surface and shifting the sediment to the central part of the bottom 3. After this operation is completed, the nozzle 14 opens and the sediment is removed.

 The combined action of all heating surfaces, the circulation of heated air and the rotational motion of the original liquid contribute to the intensification of the evaporation process.

 The proposed evaporator has high performance. The use of an additional horizontal heating disk significantly increases the surface area of heat transfer, and this helps to increase the intensification of the evaporation process. The design of the evaporator allows the reuse of the heat of vapor to reheat the air. The use of a device for cleaning the heating surface and removing sludge allows the separation of solid particles, purifies the initial liquid and increases the life of the evaporator.

Claims (1)

 An evaporator with forced circulation, comprising a vertical body with a bottom made in the form of a truncated cone, a main heating chamber installed under the bottom, an additional heating element mounted parallel to the bottom and at a certain distance from it, a device for cleaning the heating surface and removing sediment mounted on the bottom in the form of one or more scrapers mounted on the shaft, nozzles for introducing a solution, for outputting one stripped off product, for removing steam, for entering and leaving a coolant, characterized in that Tel'nykh heating element is a horizontal drive shaft is hollow and its inner cavity forms an output connection for the evaporated product, and a bend output steam air heater is installed, which is connected by piping with fan and one or more ducts, arranged tangentially to the vertical housing.

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