RU2259514C1 - Instant-boiling evaporator - Google Patents

Abstract

FIELD: thermal engineering; fresh water production from brine (salt water).

SUBSTANCE: proposed instant-boiling evaporator has housing, partition, flash chamber, condensation chamber with heat-transfer tubes, evaporated water and distillate inlet and outlet pipes; condensation chamber in central part is provided with vertical plate tightly joined with partition, evaporator effect, ceiling part, and bottom of condensation chamber; the latter is provided, in addition, with guide partitions equally spaced apart either side of vertical plate, this space being reducing along steam flow. Vapor space of condensation chambers disposed either side of vertical plate is proposed to be joined with at least one vapor channel to improve heat-transfer characteristics of evaporator, as well as to localize nondensables and to effectively discharge them.

EFFECT: enhanced capacity and improved vapor separation characteristics of evaporator.

1 cl, 2 dwg

Description

The invention relates to the field of power engineering and can be used in the technology of producing fresh water from brackish or sea water.

Known evaporators of instant boiling (patent No. 2218972), consisting of an expansion chamber and condensation.

However, in these evaporators in the condensation chambers, aerodynamics of steam flows are not ruled out, leading to gas contamination of the tube bundles, which reduces the heat transfer efficiency and, consequently, the efficiency of the evaporator.

The closest in technical essence and achievable technical result to the claimed technical solution is the design made according to patent No. 31337, comprising a housing, a dividing wall with windows for the passage of steam, an expansion chamber, a condenser with heat transfer tubes, pipes for supplying and discharging evaporated water and distillate .

However, this evaporator, taken as a prototype, has disadvantages.

Due to the absence of a system of guides and dividing walls in the condensation chamber, an unorganized movement of the vapor stream is possible, which leads to the formation of multiple stagnant zones with a high content of non-condensable gases, which prevent the penetration of steam into these zones, which ultimately leads to the heat exchange of the condenser heating surfaces located in these areas, reduces heat transfer efficiency, evaporator performance.

The claimed invention is aimed at solving the problem associated with improving the efficiency of the known instant boiling evaporator.

This problem is solved in an instant boiling-up evaporator, comprising a housing, a separation wall with windows for steam passage, an expansion chamber, a condensation chamber with heat exchange tubes, pipes for removing and supplying evaporated water, distillate, in that the condensation chamber in the central part is provided with a vertical plate, tightly connected to the dividing wall, the evaporator body, the ceiling part and the bottom of the chamber, and is additionally equipped with guide baffles located equidistant on both sides of t of the vertical plate, steam spaces located on both sides of the vertical plate are connected to each other by at least one steam channel, and the guide plates are spaced apart from each other, decreasing in the direction of the steam ..

The required technical result for increasing the operation of the evaporator is achieved by installing a vertical plate and guide baffles, providing a rational organization of the movement of the formed low-grade steam (t _S = 40-100 ° С) in the condensation chamber. Thanks to the vertical plate, the steam is divided into two separate flows that move in opposite directions, which reduces the likelihood of mixing, and the installation of the guide walls at a distance that decreases as the steam moves, provides unidirectional steam movement at an optimal speed, providing good ventilation for the heat transfer tubes. It should be noted that when steam comes into contact with the cold surface of tubes cooled by cold water, part of the steam condenses. Therefore, the amount of steam is reduced and in order to maintain the required steam speed, the cross-section (area) of the channels is reduced by reducing the distance between the guide plates. After the last baffle in front of the condenser tube plate, non-condensing gases are sucked off to an ejection device (not shown in the drawing) or to lower pressure chambers in multi-stage circuits.

Experimental studies have established that due to the proposed design, it was possible to maintain the heat transfer coefficient at the level of 2500-3000 kcal / m ² · h · ° C, at the same time, without partitions, this indicator decreased to 1200 kcal / m ² · h · ° C.

The increased heat transfer efficiency allows to reduce underheating and thereby increase the thermal efficiency of the evaporator and its productivity. The increase in evaporator productivity is explained by the increase in the possibility of generating steam due to adiabatic expansion, and the latter is determined by the ability of the condenser to condense this generated steam or to remove the latent heat of vaporization generated during steam condensation.

The novelty of the claimed invention is confirmed by the presence of distinctive features in comparison with the prototype.

The list of drawings.

Figure 1. Instant evaporator (side view).

Figure 2. Instant evaporator (top view).

The flash boil-off evaporator consists of a housing 1, a separation partition 2, a condensation chamber 3, an expansion chamber 4, windows 5 made in the separation partition, nozzles for the overflow of evaporated liquid 6, nozzles for the removal of non-condensing gases 9, heat transfer tubes 10, a vertical plate 7, guide walls 8, tube plate 11, steam channel 12.

The evaporator instant boiling is as follows. Overheated water through 6 enters the expansion chamber 4, where it boils, the steam formed through the window 5 enters the condensation chamber 3, where, thanks to the vertical plate 7, it is divided into two streams moving in opposite directions, and the flow rate is regulated by guide walls 8, they also provide optimal steam flushing of tube bundles of heat exchange tubes 10. Accumulated non-condensable gases in front of tube plate 11 are discharged through 9 to an ejector and further to the atmosphere.

This design of the condensation chamber ensures the optimal movement of the vapor stream, eliminating the formation of stagnant zones, providing minimal resistance to the vapor stream, which ultimately increases the efficiency of the evaporator instant boiling.

Claims (1)

An instant boiling-off evaporator comprising a housing, a separation wall with windows for steam passage, an expansion chamber, a condensation chamber with heat exchange tubes, pipes for removing and supplying evaporated water, distillate, characterized in that the condensation chamber in the central part is provided with a vertical plate tightly connected to dividing wall, evaporator body, ceiling part and bottom of the chamber, and is additionally equipped with guide baffles located equidistant on both sides of vertics of the base plate, the steam spaces located on both sides of the vertical plate are connected to each other by at least one steam channel, and the guide plates are spaced apart from each other at a distance decreasing along the steam.

Images