JPH0972694A - Method and apparatus for cleaning plate type heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for cleaning a plate type heat exchanger to heat exchange sea water with other fluid capable of performing sufficient cooling effect without public pollution. SOLUTION: The plate type heat exchanger 1 heat exchanges seal water with other fluid, and has a circulating supply route 4 of warm water branched from and connected to a sea water flow tube route 3 via route switching valves 5a, 5b, 5c, 5d, and injecting means 9 of pressurized air installed at the inlet side of the exchanger 1 on the way of the route 4 or after the valves. At the time of cleaning, the sea water is switched to the warm water, the warm water is supplied and circulated, and pressurized air is blown and suppled into the warm water at the inlet of the exchanger 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for cleaning a plate heat exchanger for exchanging heat between seawater and other fluids.

[0002]

2. Description of the Related Art For example, in a plate heat exchanger using seawater as cooling water, there is a problem that microorganisms (shellfish, algae, fungi, etc.) in seawater adhere to the plate and grow, thereby impairing heat transfer performance and fluidity performance. is there. In order to prevent adhesion of marine microorganisms, conventionally, chemical treatment such as chlorine injection has been widely performed.

[0003]

However, the above-mentioned chemical treatment such as chlorine injection is not harmless at all and may cause environmental damage.

On the other hand, microorganisms in seawater can be easily killed by hot water, and in fact, hot water sterilization is adopted as a pollution-free cleaning method in condensers of power plants overseas. .

However, this method has a problem that a sufficient cleaning effect cannot be obtained even if it is directly applied to a plate heat exchanger having many contact points inside.

An object of the present invention is to provide a method and apparatus for cleaning a plate heat exchanger for exchanging heat between seawater and other fluids, which is pollution-free and has a sufficient cleaning effect. Especially.

[0007]

In order to achieve the above object, the method of the present invention is a plate type heat exchanger for exchanging heat between seawater and other fluids.
The hot water is switched from seawater to hot water to circulate the hot water, and pressurized air is blown into the hot water at the inlet side of the plate heat exchanger for supply.

With the above structure, the microorganisms in the seawater attached to the seawater-side flow passage in the plate heat exchanger are killed by the hot water, and the plate heat exchange is performed by the pressurized air blown into the hot water. The air bubbling action is generated in the seawater side flow path of the vessel, and the marine microorganisms adhering to the plate can be positively removed.

Further, the apparatus of the present invention is a plate heat exchanger for exchanging heat between seawater and other fluids, which is branched and connected to a distribution pipe path of seawater through a path switching valve. It is provided with a circulating supply route of hot water and a means for injecting pressurized air installed on the inlet side of the plate heat exchanger in the circulating supply route of the warm water or after the route switching valve.

With the above construction, at the time of cleaning, the seawater side flow passage in the plate heat exchanger is switched from seawater to hot water to circulate the hot water, and the hot water is added to the hot water at the inlet side of the plate heat exchanger. Compressed air can be blown in and supplied.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic configuration diagram showing an example of an apparatus for carrying out the present invention, in which 1 is a plate heat exchanger and 2 is the flow of a mating fluid (for example, water or other fluid). Piping path, 3 is a seawater circulation piping path, 4 is a hot water circulation supply path, 5a, 5b, 5c and 5d are path switching valves, and 6
Is a hot water tank, 7 is an electric heater, 8 is a hot water circulation pump,
Reference numeral 9 indicates a means for injecting pressurized air.

The plate-type heat exchanger 1 is constructed so that the mating fluid and the seawater can be circulated through the respective circulation piping paths 2 and 3 to perform heat exchange.

A circulation supply route 4 of hot water is provided in the distribution pipe route 3 on the seawater side, and route switching valves 5a, 5b, 5c, 5 are provided.
It is branched and connected via d.

In the hot water circulation supply path 4, by switching the path switching valves 5a, 5b, 5c and 5d during cleaning, the hot water in the hot water tank 6 is transferred to the seawater of the plate heat exchanger 1 by the hot water circulation pump 8. It is configured to be supplied to the side distribution pipe path 3 and then to be refluxed to the hot water tank 6.

Path switching valves 5a, 5b, 5c, 5d
Are configured to perform a switching operation in relation to each other, and in a normal operating state, the valves 5a and 5b are opened, the valves 5c and 5d are closed, and at the time of cleaning,
The valves 5a and 5b are closed and the valves 5c and 5d are opened.

An electric heater 7 is installed in the hot water tank 6 and is controlled so that hot water having a temperature capable of sterilizing microorganisms in seawater (for example, a temperature of about 60 ° C.) can be supplied during cleaning. Other heating means may be used instead of the electric heater 7.

The warm water circulation pump 8 is driven for a predetermined time (for example, 3 minutes) at the time of cleaning, and is driven and controlled by manual control or automatic control by a timer or the like.

The means 9 for injecting the pressurized air is provided on the inlet side of the plate heat exchanger 1 in the middle of the circulating supply path 4 of the hot water, in particular,
It is installed between the discharge port of the hot water circulation pump 8 and the plate heat exchanger 1, and is connected to a pressurized air supply source (not shown) such as a compressor via an appropriate control valve. The pressurized air injecting means 9 is for injecting the pressurized air into the warm water for a predetermined time by opening the control valve at the time of cleaning, when the warm water circulating pump 8 circulates and supplies the warm water, or after completion. With this pressurized air, an air bubbling state can be generated in the distribution pipe path 3 on the seawater side of the plate heat exchanger 1, whereby microorganisms adhering to the plate, in particular, adhering to the contact points of the plate. It is possible to reliably remove even microorganisms.

The embodiment of the present invention is constructed as described above, and its operation will be described below. In a normal operating state, the path switching valves 5a and 5b are opened and the valves 5c and 5d are opened.
Is closed, and the mating fluid and the seawater are mutually heat-exchanged in the plate heat exchanger 1. When the microorganisms in seawater adhere to and grow on the plate as the operating time elapses, and the heat transfer performance or the flow performance of the plate heat exchanger 1 deteriorates, the cleaning is switched to cleaning. That is, the path switching valves 5a and 5b are closed, the valves 5c and 5d are opened, and the hot water circulation pump 8 is driven. Before switching to washing, the electric heater 7 is used to raise the water temperature in the hot water tank 6 to a temperature at which the microorganisms can be sterilized. As a result, the hot water in the hot water tank 6 is circulated and supplied by the hot water circulation pump 8 into the circulation pipe path 3 on the seawater side of the plate heat exchanger 1 for a predetermined time. And
The pressurized air is injected by the pressurized air injecting means 9 during or after the circulation of hot water. Thereby, the microorganisms attached to the plate can be killed by the warm water, and can be peeled and removed by the bubbling action of the pressurized air, so that the heat transfer performance and the flow performance can be recovered. After the cleaning is completed, the operation is returned to the normal operation, and the heat exchange operation is performed between the seawater and the partner fluid. The above cleaning may be performed regularly or at any time.

In the above embodiment, hot water was circulated to the seawater side during cleaning. At this time, it is preferable that the other side is empty in order to reduce heat loss of the hot water, but even if the other side is full. It is possible. In addition, circulation of hot water may be performed on both sides of the seawater side and the partner side. In this case, the same path switching valve and piping as those on the seawater side are branched and installed in the distribution piping path 2 for the counterpart fluid.

[0021]

EFFECTS OF THE INVENTION According to the cleaning method of the present invention, microorganisms in seawater attached to the seawater-side flow passage in the plate heat exchanger are killed by warm water, and the pressure applied by blowing into the warm water is supplied. By air, air bubbling action is generated in the seawater side flow path of the plate heat exchanger, the marine microorganisms adhering to the plate can be positively removed and removed, and the heat transfer performance and the flow performance can be recovered. , Does not cause pollution.

Further, according to the cleaning apparatus of the present invention, at the time of cleaning, hot water is switched to seawater and circulated and supplied to the seawater side flow passage in the plate heat exchanger, and at the inlet side of the plate heat exchanger. Pressurized air can be blown and supplied into the warm water.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of an apparatus for carrying out the present invention.

[Explanation of symbols]

 1 plate type heat exchanger 2 distribution pipe route of partner fluid 3 distribution pipe route of sea water 4 circulation supply route of hot water 5a to 5d route switching valve 6 hot water tank 7 electric heater 8 hot water circulation pump 9 injection means of pressurized air

Claims (2)

[Claims] 1. A plate type heat exchanger for exchanging heat between seawater and another fluid, wherein during cleaning, the seawater is switched to hot water to supply and circulate the hot water, and the plate type heat exchanger. A method for cleaning a plate heat exchanger, characterized in that pressurized air is blown into and supplied into the warm water at the inlet side of. 2. A plate heat exchanger for exchanging heat between seawater and another fluid, comprising: a circulation supply path for hot water branch-connected to a distribution piping path for seawater through a path switching valve. And a means for injecting pressurized air installed on the inlet side of the plate heat exchanger in the circulation supply path of the hot water or after the path switching valve, for cleaning the plate heat exchanger. apparatus.