JP2874598B2 - Rectifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rectifier for an absorption heat pump for general households using ammonia, water or the like as a working medium.

[0002]

2. Description of the Related Art Conventionally, this type of absorption heat pump is not for general households but is for business use, and as a rectifier used therein, as shown in FIG.
In a rectification tower 31 having a diameter of 200 mm or more, a rectification gas extraction pipe 32 and a partial heat exchanger 33 having a structure in which a metal pipe is wound in a coil shape (generally called a coiled pipe heat exchanger) from above.
And a shrinking portion D in which a filler 34 is disposed around the
And a gas-liquid separation section E provided with a concentrated solution inflow pipe 35 and a dilute solution take-out pipe 36.

The relationship between the rectifier and other component parts in the absorption cycle configuration will be described with reference to the generation / rectification circuit section shown in FIG. The generation / rectification circuit of the absorption cycle includes a solution pump 40, a solution heat exchanger 41, and a rectifier 3.
0, a generator 42. In addition, the absorption cycle includes a condenser, a subcooler, an evaporator, an absorber, a concentrated solution tank, an expansion valve, a pressure reducing valve, and piping connecting each component, but is omitted.

[0004] The ammonia water concentrated solution is sent by the solution pump 40 to the splitting section D of the rectifier 30, where it is heated by the splitting heat (split heat recovery). Next, the solution heat exchanger 41 exchanges heat with a high-temperature dilute solution returned from the dilute solution take-out pipe 36 of the rectifier to raise the temperature. Subsequently, the concentrated solution is supplied to the generator 4
2 and heated to a predetermined two-phase state. Then, it flows into the rectifier 30 through the concentrated solution inflow pipe 35. The equilibrium vapor of the high-temperature concentrated solution reaches the condensing section D and is cooled by the condensing heat exchanger 33 located there. At that time, the water vapor in the vapor is more easily condensed than the ammonia vapor, and most of the water vapor and a part of the ammonia vapor are dropped as a liquid. On the other hand, most of the ammonia vapor rises as it is. As a result of the process of concentrating the ammonia vapor by the cooling of the partial heat exchanger 33 being repeatedly performed in the partial condensing section D, high-purity ammonia vapor can be extracted from the rectified gas extraction pipe 32 at the top of the tower.

On the other hand, a high-temperature and low-concentration equilibrium liquid (dilute solution)
Reaches the solution heat exchanger 41 from the dilute solution outlet pipe 36 of the rectifier 30, where it is cooled by heat exchange with the concentrated solution. After that, it enters the absorber via the pressure reducing valve. Also,
The low-temperature and high-concentration ammonia vapor is supplied to the condenser, subcooler, expansion valve, evaporator,
It enters the absorber via the subcooler. In the absorber, the ammonia gas is absorbed by the dilute solution and the concentrated solution is regenerated by removing the heat of absorption.

[0006]

However, in the case of a cycle using the above-described conventional rectifier 30 (hereinafter, referred to as a basic system), the temperature of the concentrated solution flowing into the solution heat exchanger 41 is increased. The temperature of the dilute solution (which becomes an absorbing solution for absorbing ammonia gas in the absorber) flowing out of the rectifying device 30 is set to be lower than the temperature of the concentrated solution because the temperature becomes higher due to the partial heat of condensation recovered in the reservoir 30. In order to absorb the ammonia gas with the dilute solution in the absorber, it is necessary to lower the temperature of the dilute solution, and a large amount of heat as well as the heat of absorption must be discarded outside the system. As a result, the coefficient of performance of the absorption system was low.

Also, a system using a conventional rectifier is:
It was large for business use. If the size, especially the column diameter, is reduced with the conventional rectifier configuration, the rectification performance must be enhanced, as well as the size reduction of the partial heat exchanger 33. In the shrinking section D, although the shrinking performance is enhanced by using the packing 34 in combination with the shrinking heat exchanger 33, it is necessary to use a packing having a higher rectifying performance as the packing 34 used therein. There is. However, a filler having a high rectification performance generally has a large specific surface area and a small void ratio. In order to obtain the same amount of rectified gas, if the column diameter is reduced, the flow velocity of gas passing through the rectification column increases. Therefore, the phenomenon of taking out the liquid condensed in the partial heat exchanger 33, that is, so-called flooding, is likely to occur. Flooding is S
Although it can be calculated by the experimental formula of awistowski, the filling length seems to be related from experience. Furthermore, if the tower diameter is small, the liquid in the tower may be taken out through the rectification tower wall even before flooding occurs, the coefficient of performance decreases due to the reduction in rectification gas concentration, and the concentration on the suction side of the solution pump is reduced. This has led to a deterioration in the liquid balance of the cycle due to a shortage of the solution.

An object of the present invention is to solve the above-mentioned problems and to provide a rectifier having a high cycle coefficient of performance, having a small and stable rectification performance, and suitable for an absorption heat pump for general households. It is what it was.

[0009]

In order to achieve the above object, a rectifier according to the present invention has a rectification gas extraction pipe in the rectification tower from above and a part of the concentrated solution in the lower end. A decompression heat exchanger having an opening for flowing downward in the tower at the steam generation temperature, a decompression unit comprising a filler filled around the degeneration heat exchanger, and heat filled with the filler. A gas-liquid separation section having a recovery section, a high-temperature concentrated solution inflow pipe and a dilute solution removal pipe is arranged, and a gap is provided between the decompression section and the heat recovery section.

[0010] Further, in the same configuration as described above, the heat recovery section is constituted by a different filler having a higher porosity than the filler filled in the decompression section.

[0011] Further, a rectified gas outlet pipe having an outlet inside the tower is provided at the top of the tower, and a liquid rebound plate having an opening smaller than the tower body at least in the center is formed to project downward from the inside of the tower wall.

[0012]

According to the present invention, a part of the concentrated solution is caused to flow downward in the tower at the steam generation temperature from the opening at the lower end of the partial heat exchanger, so that the heat is recovered through the partial heat exchanger at the heat recovery part. Heat exchange between the concentrated solution and the equilibrium vapor of the high-temperature concentrated solution flowing into the column through the high-temperature concentrated solution inflow pipe and rising. Then, the concentrated solution flowing through the partial heat exchanger is heated by the heat of the equilibrium vapor of the high-temperature concentrated solution, and a predetermined amount of the equilibrium vapor having a lower temperature and a higher ammonia concentration than the high-temperature concentrated solution near the lower part of the condensing section is heated. Can be generated. The equilibrium vapor with a high temperature and a low ammonia concentration is used to generate a low-temperature, high-ammonia concentration vapor from the concentrated solution flowing into the tower through the decomposing section (heat recovery). It becomes steam with high ammonia concentration. At this time, since a gap is provided between the decompression part and the heat recovery part to make the filler in each part discontinuous, the filling length of each part can be shortened, and flooding can hardly occur.

In the case where the heat recovery section is made of a different filler having a higher porosity than the filler in the decompression section, the amount of liquid retained in the heat recovery section can be reduced, and more flooding occurs. Can be difficult.

Further, a configuration is provided in which a rectified gas outlet pipe having an outlet inside the tower is provided at the top of the tower, and a liquid splashing plate which projects inward and downward from the tower wall and has an opening smaller than the tower body at least at the center. Therefore, even if the gas flow velocity in the tower is increased, it is possible to prevent the liquid flowing along the tower wall from flowing out of the tower, and to secure a rectified gas concentration commensurate with the gas equilibrium temperature at the top of the tower.

[0015]

An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a rectifier, and FIG. 2 shows a circuit for generating and rectifying an absorption cycle using the rectifier.

In FIG. 1, reference numeral 1 denotes an outer diameter of the tower of 60.5 m.
m, a rectification column made of SUS304 having a wall thickness of 1.6 mm,
2 is a collection gas extraction pipe, A is a decompression part, and the outer diameter is φ6m
SUS304 pipe of 6.3 m in length, t1 mm in thickness and 6.3 m in length is wound with a diameter of 38 mm, a pitch of 8 mm, the number of turns is 53, and a winding length of 420 mm. And a filler 5 filled in the gaps of the heat exchanger 4. 6 is a 10 mm long gap made of a demister having a porosity of 95% or more, B is a 180 mm long heat recovery section filled with the filler 5, C is a high temperature concentrated solution inflow pipe 8 and a dilute solution removal pipe 9 And a gas-liquid separation unit comprising: Filler 5 includes Helipak No. 4 (size 5
mm, specific surface area 1700 m ² / m ³ , porosity 87%). Note that demisters 10 are actually arranged above and below for the purpose of holding the filler 5 in the decompression section A and the heat recovery section B.
The dilute solution take-out pipe 9 is 5 mm from the bottom of the rectification tower 1.
The opening is positioned at the height of the upper part and taken out upward.

The operation of the rectifier having the above configuration will be described with reference to FIG. 2 in relation to the absorption cycle. By the solution pump 11, a part of the concentrated solution is sent to the fractionator A, and the rest is sent to the solution heat exchanger 12. The concentrated solution sent to the solution heat exchanger 12 exchanges heat with the dilute solution flowing out of the dilute solution take-out pipe 9 of the rectifier, and is heated and heated. Subsequently, the generator 13
Is heated to the temperature of a predetermined two-phase region, and flows into the rectifier through the high-temperature concentrated solution introducing pipe 8.

On the other hand, the concentrated solution sent to the condensing section is heated by the heat of condensing and is heated to the steam generation temperature. Then, the steam is introduced into the rectifier through the opening 3 of the partial heat exchanger 4 at the steam generation temperature. Such a method of introducing a part of the concentrated solution into the rectifier (hereinafter referred to as a branching method) can increase the coefficient of performance COP as compared with the basic method. The reason is,
In the heat recovery section B, a part of the heat of the high-temperature concentrated solution flowing through the generator 13 and a part of the concentrated solution flowing into the rectifier at the steam generation temperature from the partial heat exchanger 4 Heating generates low-temperature gas (this process is called heat recovery), and the high-temperature steam itself becomes low-temperature steam. Thus, a predetermined amount of low-temperature steam can be generated. Thus, the burden on the generator during the steam generation process can be reduced, and as a result, the COP can be increased. The heat recovery section B is designed by setting the temperature (steam generation temperature) of a part of the concentrated solution that branches and flows in as the reflux liquid temperature.

As described above, in the branching system,
Since a part of the concentrated solution flows into the rectifier from the lower part of the condensing heat exchanger 4, when the tower diameter of the rectifier is small, flooding is likely to occur. In the tower diameter of the embodiment, by providing a gap 6 between the contraction part A and the heat recovery part B, the filler 5 of the contraction part A and the heat recovery part B can be discontinuous, and flooding is performed. Was avoided, and a rectified gas throughput of 23 kg / h was obtained.

Next, a second embodiment of the present invention will be described with reference to FIG. 3 is different from FIG. 1 in that the heat recovery part B has a high porosity filler 7 different from the shrinkage part A, for example, a McMahon (size 6 mm, specific surface area 1).
(590 m ² / m ³ , porosity 95.3%). In the heat recovery section B, since it is a mere heat exchange process instead of rectification, there is no need to use a filler having a high rectification effect such as a heli-pack, and the cost can be reduced when a McMahon is used. . Further, in this case, since the porosity is high, flooding can be made more difficult to occur.

Next, a third embodiment of the present invention will be described with reference to FIGS. The embodiment of FIG. 4 is applicable to the first and second embodiments described above. A rectification gas extraction pipe 21 having an extraction port inside the rectifier tower at the top of the rectifier tower and an inner lower portion of the tower wall are provided. And a liquid splash plate 22 having an opening smaller than the tower body at least at the center. Other configurations are the same as those of the first and second embodiments. It has been confirmed by experiments that if the column diameter is small, the liquid flows out along the wall of the column, and the concentration is actually lower than the concentration of the rectified gas obtained at the rectification temperature at high pressure. In the cycle experiment, even if the rectification temperature is high, it does not significantly affect the performance, but the fact that the liquid is taken out is
This is apparent from the fact that a sufficient amount of the concentrated solution of the pump suction can be ensured by this embodiment. In this way, the amount of concentrated solution in the pump suction can be ensured, the pump operation can be guaranteed, and a stable capacity can be obtained. FIG. 5 shows another rectified gas extraction pipe 23.
Has been shown. The operation is exactly the same as in FIG.

In the above embodiment, the splitting heat exchanger 4 is of a coiled tube type, but it is needless to say that the present invention is not limited to this.

[0023]

As described above, according to the present invention, there are the following effects, and a small and practical rectifier can be provided.

(1) Since the basic structure of the rectifier has a decompression section and a heat recovery section, and a gap is provided between the decompression section and the heat recovery section, the coefficient of performance of the absorption cycle is reduced. As well as being small, stable and stable rectification performance can be guaranteed.

(2) Since the heat recovery section is filled with a filler having a higher porosity than the decompression section, more stable rectification performance can be guaranteed.

(3) Since the tower top is improved, the absorption cycle can be stabilized.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the rectifier of the present invention.

FIG. 2 is a circuit diagram of generation and rectification of an absorption cycle using the rectifier.

FIG. 3 is a sectional view showing a second embodiment of the rectifier of the present invention.

FIG. 4 is a sectional view showing the top of the rectifier.

FIG. 5 is a sectional view showing another tower top of the rectifier.

FIG. 6 is a sectional view showing a conventional rectifier.

FIG. 7 is a circuit diagram of generation and rectification of an absorption cycle using the rectifier.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rectification tower 2 Rectification gas take-out pipe 3 Partially condensed heat exchanger opening part 4 Partially condensed heat exchanger 5.7 Filler 6 Void 8 High-temperature concentrated solution inflow pipe 9 Dilute solution take-out pipe A Decompression part B Heat recovery part C Gas-liquid separation unit

Claims (3)

(57) [Claims] 1. A fractionating heat exchanger having a rectification gas outlet pipe from above in a rectification tower and an opening at a lower end for allowing a part of the concentrated solution to flow downward in the tower at a steam generation temperature. And a gas-liquid provided with a decompression unit composed of a filler filled around the partial heat exchanger, a heat recovery unit filled with the filler, a high-temperature concentrated solution inflow pipe and a dilute solution removal pipe. A rectifier in which a separation unit is arranged and a gap is provided between the decompression unit and the heat recovery unit. 2. The rectifier according to claim 1, wherein the heat recovery section is constituted by a different filler having a higher porosity than the filler filled in the decompression section. 3. A tower according to claim 1, further comprising a rectifying gas outlet pipe having an outlet inside the tower and a liquid splash plate projecting inward and downward from the tower wall and having an opening smaller than the tower body at least at the center. The rectifier according to claim 1 or 2.