RU2275559C1 - Device for contact heat recovery - Google Patents

Abstract

FIELD: heat power engineering.

SUBSTANCE: device for contact heat recovery comprises vertical housing provided with the top gas discharging collector and bottom gas supplying collector provided with openings, nozzle with sprayer, and control gate. The outlet face of the perforated conical ring with central gas bypass is mounted above its bottom base. The collector is defined by the ring chamber mounted on the housing and having common wall with it, which is provided with movably control gate. The wall and gate have openings that arranged over periphery in rows. The flowing sections of the openings in the wall of the housing and control gate increase upward. The output face of the gas bypass of the ring is provided with saw-tooth teeth.

EFFECT: enhanced efficiency.

1 cl, 4 dwg

Description

The invention relates to a power system and can be used in installations for heating water with flue gas from boiler rooms.

The known contact heat exchanger contains a vertical casing with upper gas outlet and lower gas supply manifolds, the last of which is made with holes, a nozzle with sprinklers and conical rings with central gas transfer pipes, the outlet ends of which are placed above the lower bases of the plates (SU No. 1082464, 03.30.84, No. 12).

The well-known heat exchanger is effective for high speeds of hot gas. The introduction of additional conical rings complicates the design of the heat exchanger. The design of annular conical rings leads to the formation of stagnant zones without heat transfer. The supply of hot gases to the bottom of the heat exchanger leads to additional resistance and loss of speed. The lack of redistribution of the supplied gas does not allow to create and maintain an optimal mode when changing gas parameters during operation. Heat recovery unit requires significant investment.

The well-known contact heat exchanger (SU No. 1231330, 05.15.86, No. 18) contains a vertical housing with an upper gas outlet and lower gas supply manifolds, the last of which is made with holes, a nozzle with a sprinkler, a regulating flap and a perforated conical ring with a central gas outlet pipe, an outlet end face which is located above the lower base of the hot gas supply plate.

The lateral location of the gas supply pipe creates a non-uniformity of the supplied hot gas over the cross section of the housing. The main gas stream passes through the central portion of the housing. Wall sections of the body form inefficient zones. There is no regulation of the direction of supply of hot gas. The heat exchanger has considerable complexity. There is no way to achieve the optimal operating mode of this apparatus to ensure increased productivity at low temperatures of the coolant.

The objective of the invention is to increase efficiency by intensifying heat and mass transfer.

The problem is solved in that in a contact heat exchanger containing a vertical housing with an upper gas outlet and lower gas supply manifolds, the last of which is made with holes, a nozzle with a sprinkler placed in the housing between the collectors, a movable control damper and a perforated conical ring with a central gas outlet pipe, the output end of which is located above the lower base of the ring, the lower gas supply manifold is formed by an annular chamber placed on the housing and having with the latter, a common wall on which the movable control damper is mounted, wherein said openings are made in rows in the common wall and control damper in rows along the perimeter of the housing, and their passage sections are made increasing from the bottom up. In this case, the output end of the gas transfer pipe of the ring is made with sawtooth teeth.

Figure 1 shows the contact heat exchanger; figure 2 - node I in figure 1; figure 3 - the location of the through holes when shifting the movable control flap; figure 4 is a section aa in figure 1.

The contact heat exchanger contains a vertical housing 1 with the upper gas outlet and lower gas supply manifolds 2 and 3. The heat exchange chambers 4 and the drip trap 5 are equipped with nozzles 6 and 7. Under the nozzle 7 a sprinkler 8 is placed. In order to prevent water from spreading along the walls of the heat exchange chamber 4 above the nozzle 6, it is installed conical ring 9 with a central gas outlet 10. To exclude stagnant heat transfer zones, this conical ring 9 is provided with perforation or in the form of a mesh with passage sections of holes 11 made to reduce rising from the bottom up in proportion to the height of the nozzle. The inner diameter of the conical ring 9 is made smaller than the diameter of the heat exchange chamber by an amount depending on the temperature of the gas to be cooled at the inlet and outlet of the apparatus, which makes it possible to intensify heat transfer by ensuring a constant gas velocity over the chamber cross section. To improve the outflow of liquid from the walls of the heat exchange chamber, the ring 9 is made conical with an inclination towards the axis of the heat exchanger. The inner diameter of the conical ring is equipped with a sawtooth partition 12 with teeth 13 (Fig.2), directed upwards, which are designed for uniform drainage of water around the perimeter of the ring. The inlet pipe 3 is connected to the lower looped collector 14, which is mounted on the perimeter of the heat exchange chamber 4. The inner wall 15 (Fig. 3) of the lower collector 14 is provided with openings 16. The collector 14 is provided with a baffle 17 (Fig. 4) with channels 18 for separating hot flows gas. On the side of the inner wall 15 of the manifold 14, using the shoulders 19, a movable control flap 20 is suspended to move along the perimeter of the wall of the collector 14. This control flap 20 (Fig. 3) is provided with stepwise arranged holes 21 with the possibility of overlapping holes 16 of the inner wall 15 of the collector 14. The bore holes 16 and 21 are made increasing from bottom to top. When the control flap is shifted relative to the holes 16, the passage sections of the upper row of the collector holes change to the larger (smaller) side, and the lower row to the smaller (larger) side, i.e. in inverse proportion.

Heat exchanger works as follows. Hot gas is supplied through the gas supply pipe 3 to the manifold 14, in which the gas portions are divided into the openings 16 and 21 (Fig. 3) of the wall 15 and the shutter 20. The total height sections of the openings 16 and 21 increasing in height help to align the hot gas supply across the cross section heat exchange chamber 4. Through the openings of the upper row with a large total bore cross-section, and hence lower resistance, the hot gas passes at a low speed. The pressure of the hot gas in the upper row of holes is facilitated by a partition 17 with channels 18. Gas flows at a lower speed pass closer to the walls of the chamber 4 at the location of the nozzle 6. Gas passes through the lower row of holes with a smaller total flow area at a higher speed. Entering the heat transfer chamber 4 from oppositely located holes, gas flows are summed up in the center. By adjusting the cross-sections of the openings with a valve, optimal gas distribution is achieved. By moving the movable control flap along the perimeter, the walls of the collector change in inverse proportion the flow sections of the upper and lower rows of holes, i.e. when covering the upper holes, the passage section of the lower holes increases and vice versa. Thus, the amount of hot gas supplied to the heat exchange chamber 4 is redistributed until a uniform distribution over the cross section is achieved. In this case, the organization of the direction of the main flow of the cooled gas is carried out by the bore of the ring 9. The rest of the gas passes through the holes 11 of the ring 9.

Cold water from the sprinkler 8 is supplied evenly over the cross section of the housing 1. The main flow of water passes through the passage section of the ring 9. Once on the ring 9, part of the water flows through its holes 11, which prevents the formation of 5 stagnant zones at the walls of the nozzle 6. Another part of the water flows on the conical surface of the ring 9 and evenly flows through the sawtooth partition 12 with the teeth 13 pointing upwards due to its small elevation above the inner perimeter of the ring. Flowing onto the nozzle 6 in the form of a thin film, the water is heated by an upward flow of cooled gases. Heated water flows into the catchment and is discharged as directed. Cooled gas is discharged through the nozzle 5 through the nozzle 2. During deep cooling of hot gases in combination with condensation, their volume significantly decreases along the height of the heat exchange chamber and amounts to

V = 0,9 V ₁ (T + t _out) / (T + t _Rin)

where 0.9 is a coefficient taking into account the condensation of 60-70% of water vapor contained in gases;

V ₁ , V - volumes of cooled gases at the inlet and outlet of the heat exchanger;

t _in , t _out - temperature of the cooled gases at the inlet and outlet of the heat exchanger;

T is the absolute temperature.

In the same dependence is determined by the inner diameter of the ring 9 (figure 1)

D = 0,9 D ₁ (T + t _out) / (T + t _Rin)

where D ₁ , D are the diameters of the initial flow area of the heat transfer chamber and the ring.

Thus, the intensification of the heat transfer process, increasing productivity and approaching the optimal mode of operation of the heat exchanger is ensured by devices that are easy to manufacture and use. The conical ring organizes the direction of the main flow of hot gas, and the passage of its passage section is smaller than the diameter of the heat exchange chamber by an amount depending on the temperature of the gas to be cooled at the inlet and outlet of the apparatus, which ensures constant gas velocity over the chamber cross section. The presence of a conical ring improves the outflow of fluid from the walls of the heat transfer chamber and nozzle. Perforation of the cone ring reduces the number of stagnant heat transfer zones. The sawtooth partition contributes to the uniform draining of part of the water from the plane of the conical ring. The height-increasing total cross-section of each row of holes in the wall of the annular chamber and the control flap evens out the flow of hot gas along the cross-section of the heat exchange chamber. By changing the flow cross section of the upper holes in relation to the lower ones in inverse proportion, a redistribution of the amount of hot gas supplied is achieved until a uniform distribution over the cross section of the heat exchange chamber is achieved. This is also facilitated by the installation of a partition in the annular collector, which allows to reduce the speed pressure of the upper row of holes.

Claims (2)

1. Contact heat exchanger comprising a vertical housing with upper gas outlet and lower gas supply manifolds, the last of which is made with holes, a nozzle with a sprinkler placed in the housing between the collectors, a movable control damper and a perforated conical ring with a central gas outlet pipe, the outlet end of which is located above the lower base of the ring, characterized in that the lower gas supply manifold is formed by an annular chamber placed on the housing and having with the latter a common wall on which is mounted a movable regulating valve, wherein in the common wall and the regulating flap formed by rows of said openings perimeter of the body, and their flow sections formed increasing upwards. 2. Contact heat exchanger according to claim 1, characterized in that the output end of the gas transfer pipe of the ring is made with sawtooth teeth.

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