JPS5937439B2 - Heat exchange method for waste water in a silk mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat exchange method for waste water in a silk mill that produces raw silk from cocoons. During the discharge, the hot water is heat-exchanged with low-temperature water to be used as boiling water, reeling water, etc., and this low-temperature water is heated, and heat exchange operations are performed to measure thermal economy in the silk mill. During the period from the stop to the restart, the catalytic components and cocoon layer components dissolved and dispersed in the discharged hot water solidify and precipitate and stick to the heat exchange walls, causing a decrease in heat exchange efficiency.
To provide a heat exchange method capable of performing smooth long-term heat exchange operations by preventing a drop in work efficiency due to cleaning work being performed at an unscheduled time by stopping the supply of waste water. There is a particular thing.

As is well known, silk mills that produce raw silk from cocoons use a large amount of boiling or hot water, and this is mainly done in the cocoon boiling process using a cocoon boiling machine, and the silk reeling process using a cording machine and reeling machine. It can be roughly divided into

Traditionally, the boiling water and hot water used in these operations were flushed away and thrown away, but it became necessary to reconsider thermal energy. By heating the newly used water, considerable thermal energy can be saved.

However, the cocoons handled in silk mills consist of a shaft body and a cocoon layer, and the main components of this shaft body are flea white matter and fat. It is said to contain about 30% fat, and the cocoon threads that make up the cocoon layer are 70-80% fibroin, 20-27% sericin surrounding them, and 2.5-4.
Of these, sericin is divided into easily soluble sericin and poorly soluble sericin based on its solubility in water.Easily soluble sericin is contained in large amounts in the outer layer of the surface, and poorly soluble sericin is contained in large amounts in the middle and inner layers of the surface. There is.

These shaft components and sericin are dissolved in the cocoon water and silk reeling during boiling and reeling.

Therefore, when exchanging heat between waste water in which shaft components, sericin, etc. are dissolved and dispersed, and low-temperature water to be used from now on, these shaft components must be placed on the heat exchange wall, for example, in the area where the heat exchange is to be performed. There is a risk that components such as sericin and the like may adhere, reducing the efficiency of heat exchange and impeding the flow of waste water. As a result of intensive research and repeated experiments, the inventors
Waste hot water and low-temperature water to be newly used are flowed across a heat exchange wall, and this waste water is flowing with turbulence generated on the wall surface of the heat exchange wall. heat exchange wall,
We discovered the fact that the above-mentioned shaft components and sericin do not adhere, and furthermore, when the flow of waste water is stopped, we drain the waste water from the area where the heat exchange wall exists and inject a cleaning solution for washing. It was discovered that by simply filling the cleaning solution with the cleaning solution after cleaning, the shaft components and sericin do not adhere to the surface of the heat exchange wall during this time. No matter how the flow of hot water is interrupted depending on the operating conditions, the heat exchange wall will remain clean for a long period of time by replacing and filling with the cleaning liquid when the flow of discharged hot water is stopped.
The heat exchange method of the present invention which does not cause a decrease in heat exchange efficiency has been obtained.

The silk mill in the present invention refers to a mill that manufactures raw silk from cocoons, and the discharged water in the silk mill refers to the discharged water from the cocoon boiling machine, the discharged water from the cording machine, and the silk reeling machine in the above-mentioned mill. Unless otherwise specified, the hot water discharged from the cording machine and the reeling machine is collectively referred to as the discharged hot water from the cord reeling machine.

In the present invention, the heat exchange wall area refers to an area where a heat exchange wall exists, and in the case of one heat exchange wall, waste water is sent to the heat exchange wall and then discharged. Area 1 until
The area from the inlet to the outlet of the waste water in one heat exchange wall, and when two or more heat exchange walls are configured as one group, the area from the first heat exchange wall in the waste water flow system. This refers to the area from the hot water inlet to the hot water outlet on the last heat exchange wall.

An example of the implementation of the present invention will be explained below with reference to the accompanying drawings. FIG. 1 is a flow sheet showing an example of the present invention, in which, for example, waste water 1 from a reeling machine is temporarily transferred to a waste water storage tank 2. It is stored.

Furthermore, low-temperature water 3 to be newly used as reeling water is stored in a low-temperature water tank 4.

Both the waste water 1 and low-temperature water 3 are passed through the vibro, 61 by the respective pumps 5, 5', and enter the heat exchanger γ, where heat is exchanged, and the waste water 1 is discharged from the waste water pipe 8 with its temperature reduced. , the low-temperature water 3 is heated and sent to the reeling machine through a pipe 9.

At this time, the heated low-temperature water may be sent directly to the reeling machine, or may be sent to a boiler (not shown) to be heated to a desired temperature.

In this heat exchanger, the waste water 1 and the low-temperature water 3 must be passed through a heat exchange wall, and this is done, for example, as shown in FIG. 2 or 3.

That is, in FIG. 2, a wall 13 made of a suitable material for heat exchange is provided between the flow path 11 of the discharged hot water 1 and the flow path 12 of the low-temperature water 3.
Heat exchange is performed by flowing waste water 1 and low-temperature water 3 into channels 11 and 12, respectively.

Note that for convenience of explanation, the heat exchange wall 13 is shown by a dotted line.

This point also applies to FIGS. 2 and 4.

At this time, the waste water 1 and the low-temperature water 3 may be fed in the same direction, or may be fed directly so as to flow in different directions.

At this time, in order to create turbulence on the side surface of the heat exchange wall 13 through which the discharged hot water flows, the flow path 11 of the discharged hot water 1 is narrowed, and the surface of the heat exchange wall 13 in contact with the discharged hot water 1 is made narrow. This is done by, for example, providing a large number of fine irregularities 1G on 14.

In the present invention, FIG. 2 shows a case where the heat exchange wall is composed of, for example, one, but FIG. 3 shows a case where there are two heat exchange walls. For example, the flow path 11 for discharged hot water is constituted by two heat exchange walls 13, and the flow path 12 for low temperature water is also constituted by two heat exchange walls 13'. 13 and 13' are configured in close contact.

In the figure, the heat exchange walls are shown slightly apart from each other in order to clearly explain the configuration, but in reality, the heat exchange walls 13 and 13' are closely spaced, and between these Heat exchange takes place.

FIG. 4 shows this as a flow sheet.

These explain the heat exchange that takes place between the discharged hot water and the low-temperature water that is to be used. During the heat exchange operation, the discharged hot water is sent into the flow path of the discharged hot water, and the low temperature water is While low-temperature water is flowing through the water flow path and exchanging heat, the surface of the heat exchange wall that is in contact with the waste water, even for a considerable period of time,
In addition, in the flow path of the drained hot water, there was no phenomenon of sedimentation or adhesion of the shaft components or cocoon layer components that would have been dissolved and dispersed in the drained hot water, and the treatment continued. was possible.

This appears to be caused by turbulent flow generated at the heat exchange wall.

However, since silk mills do not operate 24 hours a day due to shift work, all machines are stopped at the end of the day.
Currently, the system remains shut down until the next day's work begins.

Or even during operation, the machine may be stopped for several hours, and furthermore, even when the machine is in operation, the heat exchange operation may be interrupted or stopped, and at this time, If the shaft component or cocoon layer component in the drained water settles in the exchange area or adheres to the vessel wall, it may cause no problem even if the treatment is continued for any length of time during the treatment operation, but the operation may be interrupted. If the heat exchange operation is stopped or interrupted, the efficiency will be hindered, and it is inconvenient that the heat exchange efficiency will be lowered. The precipitation of shaft components and cocoon layer components as described above can be eliminated by simply replacing the discharged hot water in this area with a cleaning solution in the discharged hot water flow system in the wall area and filling this area with the cleaning solution. No adhesion occurred at all.

For example, you can do this as follows,
To explain this with reference to FIG. 1, a valve 15 is provided on the vibro that enters the heat exchanger 1, and a valve 16 is provided on the waste water pipe 8 that sends out the waste water after heat exchange. It is preferable to provide it outside the vessel γ.

The vibro also has a cleaning liquid pipe 1 that leads to the cleaning liquid tank 17.
The pipe 18 is preferably provided with a pump 19 and a valve 20, and the vibro is preferably provided with a drain pipe 22 having a valve 21.

Note that 23 is a drain tank. Now, when the heat exchange operation is stopped, the operation of the pumps 5 and 5' is stopped, and the flow of the discharged hot water and low-temperature water is stopped.

At this time, the valve 20 of the cleaning liquid pipe 18 is closed.

Subsequently, valves 15 and 16 are closed, then valve 20 of the cleaning liquid pipe is opened, pump 19 is operated, and
When the valve 21 of the drain pipe 22 is opened, the valve 15
The drained hot water between and 16 is discharged from the drain pipe 22, and the vibro B is filled with cleaning liquid instead.

When this replacement progresses and the cleaning liquid begins to be discharged from the drain pipe 22, the operation of the pump 19 is stopped and the valve 2
If 0 and 21 are closed, the heat exchange wall area of the exhaust hot water flow system is completely replaced and filled with the cleaning liquid, so it is sufficient to leave the area still for a while.

To start the heat exchange operation, the valves 15 and 16 are opened and the pumps 5, 5' are operated, and the cleaning liquid is forced into the waste water and discharged, and the heat exchange operation is restarted.

In the explanations with reference to FIGS. 1 to 4, the heat exchange wall area according to the present invention corresponds to the area from the inlet to the outlet of the heat exchanger where heat exchange is performed by the heat exchange wall.

In the present invention, replacement of waste hot water and cleaning liquid means replacing the same amount, that is, draining hot water is discharged, and replacing it with the same amount of cleaning liquid as the amount of discharged waste water is injected. This does not necessarily mean that after the hot water is discharged, a cleaning liquid is injected, and after a considerable amount of the cleaning liquid has passed, this cleaning liquid is left as is.

Further, in some cases, after a considerable amount of the washing liquid has passed through, the flow system may be emptied without leaving the washing liquid as it is.

The cleaning water used in the present invention is desirably alkaline, such as an aqueous solution of caustic soda, but is not limited to this, and water can also be used as the cleaning solution. .

Next, the present invention will be explained in more detail with reference to Examples.

Example: In a heat exchanger with 20 heat exchange walls and a heat transfer area of 1.16 m', an average flow rate of 10 m
At the same time, low temperature water with an average temperature of 16.5°C to be used for reeling is supplied at an average flow rate of 10°C.
As a result of heat exchange between the two, the low temperature water of 16.5°C was heated to 23.8°C and was supplied to the boiler or directly as working water.

At this time, the heat exchanger inlet pressure of the reeling waste water at the start of heat exchange is 0.3 kg/iG, and the heat exchanger inlet pressure of the reeling waste water when the heat exchange is stopped after the elapse of time is 0.4 kg/iG. ant
It was G.

When the heat exchange is stopped, the supply of the reeling waste water is stopped, and about 1 liter of a 0.04% aqueous solution of caustic soda is added from the outlet side of the heat exchanger.
After injecting and washing for 5 minutes, the caustic soda aqueous solution remains as it is, and when the heat exchange starts the next day, the caustic soda aqueous solution is discharged and the thread reeling waste water is supplied again. Along with this, low temperature water is supplied as described above to restart the heat exchange. However, the pressure at the inlet of the heat exchanger for reeling and discharging hot water when restarting was 0.3 kg/iG,
There was no problem with continued operation.

On the other hand, if the heat exchanger is left as it is without washing or other means when the heat exchange is stopped, the pressure at the inlet of the heat exchanger for reeling waste water will be 0.35 kg/c when the heat exchange is restarted the next day.
In TLG, the average flow rate of the reeling and discharging hot water decreased to 9861/hour.

As a result, the low-temperature water was only heated to about 20.5°C.

Is the heat exchanger inlet pressure of the reeling waste water 0.4 kg/cI when the heat exchange is stopped on the second day? It had risen to LG, but recently it has increased to 5.
The heat exchanger was left as it was, and by the time heat exchange started on the third day the following day, it was almost impossible to feed the reeling waste water, so the heat exchanger was disassembled and cleaned.
The heat exchanger was filled with a paste-like substance consisting mainly of sericin.

[Brief explanation of the drawing]

The attached drawings show an example of the implementation of the present invention, and FIG. 1 is a route diagram showing heat exchange between reeling waste water and low-temperature water, FIG. 2 is a side view showing an example of a heat exchange wall, and FIG. FIG. 4 is a route diagram showing an example of a heat exchanger consisting of a large number of heat exchange walls, and FIG. 4 is a side view showing an enlarged part of the one in FIG. 3. 1: Discharged hot water, 3: Low temperature water, 1: Heat exchanger, 11: Discharged hot water channel, 12: Low temperature water channel, 13. 13th generation heat exchange wall.

Claims (1)

[Scope of Claims] 1. Discharged water from a silk mill, in which silkworms, cord waste, etc., are filtered and removed, and shaft components, cocoon layer components, etc. remain dissolved or dispersed, and newly boiled cocoon water, Low-temperature water to be used as cording water, reeling water, etc. is flowed across a heat exchange wall, and the discharged hot water causes turbulence on the heat exchange wall surface through which the discharged hot water flows. When performing heat exchange with the low-temperature water while being heated, when the flow of waste water is stopped or interrupted due to the termination or interruption of factory operations, the flow of waste water to the heat exchange wall area is stopped. Subsequently, a cleaning solution is supplied to the waste water flow system, and the heat exchange wall surface is left in the waste water flow system filled with the cleaning solution, and then the waste water is started flowing again. 1. A method for heat exchange of waste water in a silk mill, characterized in that at the start of the process, heat exchange is restarted while the washing liquid is being discharged by flowing the waste water as it is. 2. A heat exchange method for waste water in a silk mill as claimed in claim 1, wherein the waste water is boiled cocoon waste water discharged from a cocoon boiling machine. 3. The method for heat exchange of waste water in a silk mill as set forth in claim 1, wherein the waste water is yarn reeling waste water discharged from a cording machine and/or a thread handling machine. 4. The method for exchanging heat of waste water in a silk mill according to claim 1, wherein the heat exchange wall area is composed of a plurality of heat exchange walls. 5. The method for heat exchange of waste water in a silk mill as claimed in claim 1, characterized in that the cleaning liquid is sent from the outflow side of the heat exchange wall area for cleaning.