JPS6176884A - Method of circulating condensate in split type heat exchanger - Google Patents

Abstract

PURPOSE:To make it possible to circulate a condensate without being affected by a heat difference due to pressure loss by providing an opening and closing valve in a condensate pipe at the lower part of a condensing part to intermittently open or close the same, and causing the condensate to flow down. CONSTITUTION:One or two or more opening and closing valves 7a and 7b are mounted at the lower part of the condensing part of a heat insulating condensate pipe 5 connecting the side of a condensate 6 of an evaporating part A to the side of a condensate of a condensing part, at a suitable interval, and a heat exchanger is actuated in a closed state. When the condensate 6a is accumulated on the opening and closing valve 7a, the opening and closing valve 7a is opened and the accumulated condensate 6a is caused to flow down. Thereafter, the opening and closing valve 7a is closed. Since the condensate 6b which has flowed down is accumulated on the valve 7b, the valve 7b is opened to cause the condensate 6b to flow down, and then the valve 7b is closed. As a result, even is there is a high pressure difference, it is possible to cause the circulating condensate to flow down.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for refluxing condensate in a separate heat exchanger that applies the principle of a heat pipe, and particularly relates to a method for refluxing condensate in a separate heat exchanger that applies the principle of a heat pipe.

This facilitates the reflux of condensate even when there is a large head difference between the condensate in the evaporator and condensate due to vapor pressure loss at the same time, or when the reflux condensate value is small at high temperatures.

[Conventional technology]

Generally, heat exchangers using heat pipes with excellent thermal conductivity are used for the apparent recovery of factory exhaust gas, waste water, etc. A heat pipe has a working fluid sealed inside a tubular body, with one end serving as an evaporator and the other end as a condensing part, which undergoes phase transformation (evaporation/condensation) of the working fluid.
heat transfer by condensation). However, depending on the conditions for sensible heat recovery, it is necessary to place the evaporation section and the condensation section at separate locations.On the other hand, if the heat pipe is made longer, a mixed flow of steam and condensate will occur, and the flow of condensate will be reduced. This has the disadvantage that the performance is significantly reduced due to the inhibition of

To improve this, a separate heat exchanger that applies the heat pipe principle has been developed and put into practical use. That is, as shown in Fig. 4, a plurality of vertical heat transfer tubes (1) are arranged in parallel, headers (2) and (3) are attached to both ends of the tubes, and the evaporation section (A
＞ and a condensing part (B), which are placed in separate positions to form a vapor side header (2) of the evaporating part <A) and the condensing part (B).
, (2) are connected by an insulated steam pipe (4), and the condensate side headers (3), (3) are connected by an insulated condensate pipe (5) to form a closed circulation circuit, and the working fluid ( 6) is used.A vertical separation type heat exchanger is used. In addition, as shown in Fig. 5, a plurality of horizontal heat transfer tubes are installed in parallel, and headers are attached to both ends of the tubes to form an evaporating section (A> and a condensing section (B)).
are placed at separate locations as in the case of Fig. 4, and their steam sides are connected by an insulated steam pipe (4), and their condensate sides are connected by an insulated condensate pipe (5). Hydraulic fluid inside (6)
A horizontal separate type heat exchanger is also used.

In all of these vt systems, steam generated in the evaporator is condensed in the condenser and then refluxed back to the evaporator for heat exchange. During this reflux, due to the pressure loss inside the pipe, there is a head difference △ between the evaporated liquid level in the evaporator section (A) and the east line liquid level in the adiabatic condensate pipe (5), as shown in Figures 4 and 5.
produces h. Conventionally, this head difference Δh is predicted in advance and a difference is created between the heights of the evaporating section and the condensing section, or if this height cannot be achieved, the condensed liquid is forcibly refluxed using a pump or the like.

[Problem that the invention seeks to solve]

In the heat exchanger described above, when the speed of steam flowing in the adiabatic steam pipe increases or the length of the adiabatic steam pipe becomes long, the steam pressure loss also increases, and in such cases, the head difference △h
In some cases, it becomes necessary to position the condensing section 10 m or more higher than the evaporating section. The equipment cost of such a separate heat exchange device is extremely high.

It is known that increasing the diameter of the insulated steam pipe can solve this problem, but increasing the diameter requires thickening the wall in order to withstand pressure, which significantly impairs economic efficiency. It turns out. It is also known that a circulation pump can be used, but the use of a pump is not only expensive but also has the disadvantage of poor reliability.

[Means for solving problems]

In view of this, as a result of various studies, the present invention has developed a condensate liquid of a separate type heat exchanger that can easily reflux the condensate even when the head difference Δh due to pressure loss is large and the amount of condensate that is refluxed at high temperature is small. The reflux method was developed by arranging the evaporation section and condensation section separately, and connecting the steam side with an insulated steam pipe and the condensate side with an insulated condensate pipe to form a closed circulation circuit. In the method of enclosing a working fluid in the circuit and exchanging heat through phase transformation (evaporation and condensation) between the evaporation section and the condensation section, an on-off valve is provided in the condensate pipe below the condensation,
The valve is intermittently opened and closed to cause the condensate accumulated on the valve to flow down intermittently.

That is, the present invention provides a method for converting the condensate (6) of the evaporation section (A> Although not shown in the figure, there is one or more on-off valves (the figure shows the case of two valves) located below the condensate of the adiabatic condensate pipe (5) that connects the condensate side of the condensate part. 7a) and (7b) are installed with a gap between them, the heat exchanger is operated with these closed, and when the condensate (6a) has accumulated on the on-off valve (7a), the on-off valve (7a) is opened. , the accumulated condensate (6a) is allowed to flow down, and then the on-off valve (7a) is closed.

The condensate (6b) that has flowed down collects on the on-off valve (7b), so open the on-off valve (7b) and let it flow down.
Close the on-off valve (7b). This operation is repeated to reflux the condensate. That is, one or more on-off valves are provided, and the condensate is made to flow down intermittently by opening and closing the valves.

The recirculating condensed i1M valve uses a solenoid valve, a rotary valve, an on-off valve connected to an electric operating machine, etc.
Opening/closing is automatically controlled by pressure difference. If the steam pressure loss is small, one valve is sufficient as an on-off valve, but
Install at least two or more on the steam LjD or large lifting platform,
In order to soften the impact caused by the opening and closing of the on-off valves, it is desirable to provide three or more on-off valves (7) as shown in FIG.

(Function) When the on-off valve is closed, a pressure difference exists between the upper and lower sides. Reflux condensate accumulates in the on-off valve. When the on-off valve is opened, the accumulated reflux condensate flows down due to gravity.

If the on-off valve is then closed, the reflux condensate will begin to accumulate again. By performing this operation intermittently, the reflux condensate can flow down even if there is a pressure difference.In particular, by performing multiple stages of this operation, the reflux condensate can flow down even under a fairly high pressure difference. can flow down.

〔Example〕

Made of material S T B 35, outer diameter 38.1, wall thickness 2
On the outer periphery of a tube with a length of 11000a, a radial twin made of material 5PCG with a thickness of 1.
Place a header with a diameter of 50.8@m on both ends of the wood to form the evaporation part and condensation part. place,
A cut with an outer diameter of 38.1 qm on the steam side! ! ! ! They were connected by a steam pipe, and the condensate side was connected by an adiabatic condensate pipe with an outer diameter of 25.4 m+ to form a vertical separation type heat exchange device as shown in FIG. In this way, water is filled in the device as a working fluid at 50Vo1% of the evaporation section, and 4.0 to 1 g per bottle is filled in the evaporation section.
, 0x103 Kcal/goh was added to perform heat exchange, and the experiment was conducted by forcibly creating a pressure drop in the steam piping. The result is 500-1500Kca1/Trt
The heat transfer coefficient was only 1q of h°C. This was because the head difference Δh based on vapor pressure loss was large and the liquid level in the evaporator was low.

Next, in the above device, a first
As shown in the figure, two electromagnetic on-off valves were installed at an interval of 300 mm, and the on-off valves were alternately opened and closed every 30 seconds to allow the condensate to flow down intermittently, and a similar heat exchange was performed. 150
Heat transfer coefficients of 0-2000 Kcal/1rLh°C were obtained. This is hard 1i! By installing an on-off valve in the liquid pipe and opening and closing it intermittently to allow the condensate accumulated in the valve to flow down intermittently by gravity, the condensate can be refluxed without being affected by the steam head difference △h. This is because it can be done.

〔Effect of the invention〕

As described above, according to the present invention, the head difference due to pressure loss △
It is now possible to reflux the condensate without being affected by h, making it possible to increase the length of the adiabatic vapor value, and further expanding the scope of use of the separate heat exchange device, such as eliminating the need for a reflux pump. It has a remarkable effect that can be expanded (
It is something that

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of main parts showing an example of the fA flow method of the present invention;
Fig. 2 is an explanatory diagram of the main part showing another example of the reflux method of the present invention, Fig. 3 is an explanatory diagram of the main part showing still another example of the JW flow method of the invention, and Fig. 4 is an explanatory diagram of the main part showing another example of the reflux method of the present invention. FIG. 5 is an explanatory diagram showing an example of a conventional horizontal type separation type heat exchange device. A... Evaporation i! ill B... Condensing section 1.
...Heat transfer tubes 2, 3...Header 4...Insulated steam pipes 5...Insulated condensate pipes 5, 6a, 6b...
・Condensate 7, 7a, 7b...Opening/closing valve ・1 ・' Agent Patent attorney Minoura Kiyosu 飄)-l'' Figure 3 Figure 4

Claims (2)

[Claims] (1) The evaporation section and the condensation section are arranged separately, and the steam side is connected by an insulated steam pipe, and the condensate side is connected by an insulated condensate pipe to form a closed circulation circuit, and the circuit is operated. In the method of enclosing a liquid and exchanging heat through phase transformation (evaporation and condensation) between the evaporation section and the condensation section, an on-off valve is provided in the condensate pipe below the condensation, and the valve is opened and closed intermittently to 1. A method for refluxing condensate in a separate heat exchange device, which is characterized by causing condensate accumulated in a separate heat exchanger to flow down intermittently. (2) Provide two or more on-off valves at intervals in the condensate pipe,
2. A method for refluxing condensate in a separate heat exchanger according to claim 1, wherein the valves are sequentially opened and closed to cause the condensate accumulated on the valves to sequentially flow downward.