JPH0824837A - Waste water treatment apparatus in painting equipment - Google Patents

Abstract

PURPOSE:To enhance the recovery efficiency of impurities in waste water and to prevent the environmental pollution and to reduce the maintenance work. CONSTITUTION:An evaporation tank 2 storing waste water W and an evaporation heater 4 heating the waste water W stored in the evaporation tank 2 from a high temp. source H through a heat transfer partition wall 4b are provided and, to the evaporation tank 2, a purified steam passage 5 leading out steam V of waste water W from the upper part of the tank 2, an upper impurity lead-out passage 8 leading out floatable impurities O from the vicinity of the surface of the stored waste water W and a lower impurity lead-out passage 9 leading out precipitable impurities S from the bottom part of the tank are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wastewater treatment device in a painting facility for recovering impurities contained in wastewater produced by washing an object to be coated with washing water.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional structure of a waste water treatment apparatus as described above in a coating facility. Impurity-containing waste water W generated by cleaning an object to be coated is passed through a waste water tank 1 and a waste water channel 3 to an upper part of a treatment tower T. And dropped on the packing layer X in the processing tower,
On the other hand, the high temperature combustion gas G generated by the burner B is supplied to the lower part of the processing tower T, and this high temperature combustion gas G is passed upward with respect to the packing layer X, whereby during the passage of the packing layer X. The dropping waste water W is heated by directly bringing it into gas-liquid contact with the high-temperature combustion gas G, and by this heating, the pure water component in the dropping waste water W is evaporated to increase the impurity concentration in the waste water W and concentrate the waste water W. .

Then, the combustion gas G passing through the packing layer X
Is discarded from the exhaust passage E together with the steam V of the waste water W, while the concentrated waste water W discharged from the bottom of the processing tower T is once received by the recovery tank 11, but the concentrated waste water W in this recovery tank 11 passes through the circulation path R. Via the above-mentioned untreated wastewater W from the wastewater channel 3 again onto the packing layer X in the treatment tower T, whereby the concentration degree of the concentrated wastewater W derived from the bottom of the treatment tower T (in other words, The concentration of impurities is increased so that the impurities in the wastewater before treatment are collected in the collection tank 11 in the form of concentrated wastewater.

[0004]

However, the above conventional device has the following problems (a) to (c). (A) Dust generated due to impurities in the waste water is contained in the combustion gas G that is discarded from the exhaust passage E together with the water vapor V, which may lead to dust pollution.
To prevent this, a separate processing device for separating and removing dust from the combustion gas G is required.

(B) The packing material layer X in the processing tower T is contaminated by the product derived from the impurities in the waste water, and the packing material layer X becomes clogged when the contamination progresses. Maintenance work for X is required periodically.

(C) High temperature combustion gas G generated by burner B
Almost all of the retained heat of (1) is discarded outside the system as retained heat of the combustion gas G and the steam V to be discarded from the exhaust passage E, and therefore the energy loss is extremely large.

A first object of the present invention is to improve the efficiency of collecting impurities in wastewater, prevent pollution, and reduce maintenance work with a rational recovery structure.

A second object of the present invention is to prevent environmental deterioration due to generated steam and to reuse the generated steam (in other words, reuse of water).

A third object of the present invention is to reduce the required heat energy by rational recovery of exhaust heat.

A fourth object of the present invention is to promote the evaporation of waste water by a rational method to improve recovery efficiency and reduce required heat energy.

[0011]

[Means for Solving the Problems]

[First characteristic configuration] The first characteristic configuration of the present invention is a wastewater treatment device in a coating facility for recovering impurities contained from wastewater generated by cleaning of an object to be coated with cleaning water, and an evaporation tank for storing the wastewater, A vaporization heater for heating the stored wastewater in the vaporization tank from a high temperature source via a heat transfer partition is provided, and in the vaporization tank, a purified steam path for deriving the vapor of the wastewater from the tank upper part, This is because an upper impurity lead-out path for leading out floating impurities from the vicinity of the water surface of the stored wastewater and a lower impurity lead-out path for leading out settling impurities from the tank bottom are provided.

[Second Characteristic Configuration] A second characteristic configuration of the present invention is to identify a specific configuration suitable for carrying out the first characteristic configuration described above. The purpose is to provide a condenser for cooling and condensing with a cooling means.

[Third Characteristic Configuration] A third characteristic configuration of the present invention is to identify a specific configuration suitable for carrying out the above-mentioned second characteristic configuration, and is derived by the purified water vapor passage as the cooling means. A heat exchanger for exchanging heat between the steam of the waste water and the waste water before treatment sent to the evaporation tank is provided.

[Fourth Characteristic Configuration] A fourth characteristic configuration of the present invention is to identify a specific configuration suitable for carrying out the above-mentioned second or third characteristic configuration, and to reduce the pressure inside the condenser. This is because the pump means for operating is provided.

[0015]

[Action]

[Operation of First Characteristic Configuration] In the first characteristic configuration, the stored wastewater in the evaporation tank is heated by the evaporation heater to evaporate the pure water component in the wastewater to concentrate the stored wastewater. In addition, this heating uses a form in which the waste water is heated by the high temperature source via the heat transfer partition wall, thereby preventing impurities and generated steam in the waste water from leaking to the high temperature source side of the evaporation heater.

Then, the generated steam (that is, purified steam containing no impurities) is led out from the upper part of the tank to the purified steam passage, while the impurities in the wastewater, such as oily matter, which are floatable, are stored in the tank during the storage process. With the above heating and concentration, the accumulated wastewater is floated and accumulated in the vicinity of the surface of the water, and is discharged and collected by the upper impurity discharge path. As it is heated and concentrated, it is deposited and accumulated at the bottom of the tank, and is discharged and recovered through the lower impurity discharge path.

[Operation of Second Characteristic Configuration] In the second characteristic configuration, the steam (purified steam) of the waste water led out through the purified steam path is cooled and condensed in the condenser,
The derived steam is condensed as purified water.

[Operation of Third Characteristic Configuration] In the third characteristic configuration, the steam of the waste water derived through the purification steam passage and the untreated waste water to be sent to the evaporation tank are heat-exchanged in the heat exchanger as the cooling means. Thus, the derived steam is cooled and condensed, and the preheated wastewater to be sent to the evaporation tank is preheated by utilizing the retained heat of the derived steam.

[Operation of Fourth Characteristic Configuration] In the fourth characteristic configuration, the inside of the condenser communicating with the evaporation tank via the purified water vapor passage is reduced in pressure by the pump means.
The inside of the evaporation tank is depressurized, which promotes evaporation of waste water in the evaporation tank.

[0020]

【The invention's effect】

[Effect of First Characteristic Configuration] According to the first characteristic configuration of the present invention, impurities in the waste water leak to the high temperature source side of the evaporation heater (that is, the impurities in the waste water are Since the impurities in the wastewater are collected in a form that eliminates the dust generated as a result of being discarded together with the combustion gas), the efficiency of collecting impurities can be improved and the pollution caused by such leakage of impurities can occur. Can be prevented without the need for a separate processing device.

In addition, the packing layer required to bring the dripping wastewater and the combustion gas into direct gas-liquid contact in the conventional apparatus (that is, the packing layer that causes clogging by the product from which impurities originate) is also used. Since it is unnecessary, maintenance work for the device can be greatly reduced.

[Effect of Second Characteristic Configuration] According to the second characteristic configuration of the present invention, by condensing the generated steam, it is possible to prevent the environmental deterioration due to the disposal of the steam, and to purify the purified water. Resource saving and cost reduction can be promoted by reusing it for cleaning the coated object.

[Effect of Third Characteristic Configuration] According to the third characteristic configuration of the present invention, the pretreatment wastewater is preheated by utilizing the retained heat of the generated steam, so that the generated steam having a large retained heat is generated together with the combustion gas. The thermal efficiency of the device can be greatly improved, and energy saving and cost saving can be effectively achieved, as compared with the above-mentioned conventional device which has been discarded from the processing tower.

[Effect of Fourth Characteristic Configuration] According to the fourth characteristic configuration of the present invention, by promoting the evaporation of the waste water by lowering the pressure, the efficiency of collecting impurities in the waste water can be improved and the waste water heating is required. The amount of heat can be saved and energy savings and cost savings can be achieved.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a device configuration of a wastewater treatment device in a coating facility. This wastewater treatment device contains impurities (for example, oil content and oil content) from wastewater W generated when an article to be coated is washed with wash water before coating. Separately collect the phosphoric acid compound scale).

Reference numeral 1 denotes a waste water tank for collecting and temporarily storing the waste water W generated in the part to be coated to be cleaned, and 2 a waste water W sent from the waste water tank 1 through the waste water channel 3, and storing the waste water W. The evaporation tank for performing the concentration process is equipped with an evaporation heater 4 for heating the stored wastewater W.

Further, a purifying steam path 5 for leading out the steam V generated in the tank from the inside of the tank is connected to the upper end of the evaporation tank 2, and the tank side is located near the water surface height of the stored wastewater W. Is connected to an upper impurity discharge path 8 for discharging floating impurities O such as oil from the inside of the tank through the submerged weir structure 6 and the discharge tank 7, and further, the lower end portion of the tank bottom formed in an inverted cone shape. Contains scaleable impurities S such as scale
Is connected to the lower impurity lead-out path 9 for leading out from the inside of the tank.

The evaporation heater 4 is a high temperature steam distribution jacket 4a having a structure in which a large number of upstream and downstream passages f of the stored wastewater W are secured.
Is installed in the tank 2 at a position lower than the water surface of the stored wastewater W, and high-temperature steam H as a high-temperature source supplied from the high-temperature steam supply passage 10 is circulated in the jacket 4a to form a heat transfer partition wall. Jacket wall 4b
The stored wastewater W is heated via.

That is, the stored wastewater W is heated by the evaporation heater 4 to evaporate the pure water component in the wastewater to concentrate the stored wastewater W. However, the jacket structure described above is employed as a heat transfer partition wall. By adopting a mode in which the stored wastewater W is heated via the jacket wall 4b of the above, it is possible to prevent the impurity-containing wastewater W and the steam V generated in the tank from leaking out of the system through the circulation system of the high temperature steam H which is a high temperature source for heating. It is configured to surely prevent.

Along with the above heat concentration, the floating impurities among the impurities contained in the stored wastewater W are stored wastewater W.
Of the floating impurities in the vicinity of the water surface, and those that are sedimentable are settled and accumulated in the bottom of the tank.
Is taken out from the evaporation tank 2 by the upper impurity derivation path 8 and the sedimentation accumulated impurities S are taken out by the lower impurity derivation path 9 into the impurity recovery tank 11.

Reference numeral 12 is a steam return path for guiding the temperature-falling steam or steam condensate after flowing through the jacket.

Further, 13 and 14 are valves for opening and closing the upper impurity derivation passage 8 and the lower impurity derivation passage 9, respectively.
When the accumulation degree of each of the floating impurities O and the sedimentation impurities S is still low, these valves 13 and 14 are closed, and when the accumulation degrees thereof are high, these valves 1 and 14 are closed.
By opening 3 and 14, the floating and sinking accumulated impurities O and S are efficiently recovered.

Reference numeral 15 is a waste water pump for feeding the waste water W from the waste water tank 1 to the evaporation tank 2, and the evaporation tank 2 is controlled by the operation control of the waste water pump 15 or the control of the interposed valve in the waste water passage 3. The water surface height of the stored wastewater W at is maintained at a predetermined level (that is, the water level at which the floating accumulated impurities O can be appropriately derived through the submerged dam structure 6).

On the other hand, the steam V (purified steam containing no impurities) of the waste water W generated in the tank due to the above-mentioned heating and concentration is sequentially fed to the condenser 16 via the purified steam path 5, and the condenser 16 In 16, the water vapor V is cooled by the cooling means, condensed, and condensed as purified water. And
This purified water is led out from the condenser 16 through the condensate drainage path 17, and then reused as washing water for washing the object to be coated.

As the above-mentioned cooling means in the condenser 16, a heat exchanger 18 for pre-stage cooling, which is arranged in an upstream portion of the steam flow passage in the condenser, and a heat exchanger 19 for post-stage cooling, which is arranged in a downstream portion thereof. The heat exchanger 18 for pre-stage cooling has a form in which the heat exchanger 18 is interposed in the waste water channel 3, and the pre-treatment waste water W sent from the waste water tank 1 to the evaporation tank 2 is used as a cooling medium. It is designed to be distributed as.

That is, the introduced steam V is cooled and condensed by exchanging heat between the steam V introduced into the condenser 16 and the untreated waste water W sent to the evaporation tank 2 in the heat exchanger 18 for pre-stage cooling. At the same time, the introduced steam V (that is, the steam discharged from the evaporation tank 2)
The pre-treatment wastewater V to be sent to the evaporation tank 2 is preheated by utilizing the retained heat of.

Regarding the heat exchanger 19 for the second-stage cooling, the cooling water C is circulated as the cooling medium by the cooling water circulation passage 20 to circulate between the cooling tower 21 and the first-stage cooling. By equipping the latter heat exchanger 19 with the heat exchanger 18 for cooling, the steam V introduced into the condenser 16 is irrespective of the amount of waste water sent from the waste water tank 1 to the evaporation tank 2 and the temperature of the waste water. It is designed to ensure a sufficient amount of cooling for surely condensing and condensing the entire amount.

Reference numeral 22 denotes a circulation pump for the cooling water C. Depending on the case, the heat exchanger 19 for the latter stage cooling is required by the operation control of the circulation pump 22 or the control of the interposition valve in the cooling water circulation passage 20. You may make it adjust the cooling water circulation amount according to the cooling amount performed.

Reference numeral 23 is a vacuum pump for reducing the pressure inside the condenser, and the inside of the evaporation tank 2 is reduced by lowering the pressure inside the condenser 16 communicating with the evaporation tank 2 through the purified water vapor passage 5. Is reduced to accelerate the evaporation of the waste water W in the evaporation tank 2.

Another Embodiment Next, another embodiment will be described.

(1) The concrete structure of the evaporation heater 4 can be modified in various ways. For example, a tube body for circulating the high temperature steam H or a body for circulating the high temperature combustion gas is provided in the tank, The pipe wall of the pipe body or the body wall of the body may be used as a heat transfer partition to heat the stored wastewater W by the high temperature steam H or the high temperature combustion gas.

(2) As the heating high temperature source used in the evaporation heater 4, various high temperature fluids such as high temperature steam and high temperature combustion gas can be adopted, and an electric heating element is used as the high temperature source instead of the high temperature fluid. You may do it.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

[Figure 1] Overall configuration of wastewater treatment equipment

FIG. 2 is a block diagram of a conventional device

[Explanation of symbols]

 W Waste water 2 Evaporation tank 4b Heat transfer partition H High temperature source 4 Evaporation heater V Steam 5 Purification steam path O Floating impurities 8 Upper impurities derivation path S Sedimentation impurities 9 Lower impurities derivation path 18 Cooling means, heat exchanger 19 Cooling means 16 Condenser 23 Pump means

Claims (4)

[Claims] 1. A wastewater treatment device in a coating facility for recovering contained impurities from wastewater (W) produced by cleaning an object to be coated with cleaning water, comprising: an evaporation tank (2) for storing the wastewater (W); An evaporation heater (4) for heating the stored wastewater (W) in the evaporation tank (2) from a high temperature source (H) via a heat transfer partition (4b), and the evaporation tank (2) First, the purified water vapor path (5) for leading out the water vapor (V) of the waste water (W) from the upper part of the tank.
And floating impurities (O) from near the surface of the stored wastewater (W)
Upper impurity derivation path (8) for deriving the settling impurities (S) and lower impurity derivation path (9) for deriving the settling impurities (S) from the bottom of the tank.
Waste water treatment equipment in coating equipment equipped with and. 2. The cooling means (18), (1) for converting the steam (V) of the wastewater (W) derived by the purification steam path (5).
The wastewater treatment device in a coating facility according to claim 1, further comprising a condenser (16) for cooling and condensing by 9). 3. As the cooling means, the steam (V) of the wastewater (W) derived by the purification steam passage (5) and the pretreatment wastewater (W) sent to the evaporation tank (2) are heat-exchanged. The wastewater treatment device in a coating facility according to claim 2, further comprising a heat exchanger (18). 4. A wastewater treatment device in a coating facility according to claim 2, further comprising pump means (23) for reducing the pressure inside the condenser (16).