JPH0137736Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an evaporative oil-water separator that separates oil contained in water by utilizing the difference in vapor pressure between the two components.

(Prior art) As a prior art of the evaporative oil-water separator,
No. 5048, in which hydrous crude oil heated to about 70°C is sprayed from a nozzle into a vacuum chamber with a degree of vacuum of about 600 mmHg, and only the water is evaporated using the difference in vapor pressure between water and oil. The water vapor is condensed and separated in a cooler, and the oil is taken out from the outlet at the bottom.

However, since crude oil is not a single component and contains components with various vapor pressures, even when spray evaporated in this way, oil vapor coexists with water vapor in the vapor phase. Therefore, the condensed water contains oil,
Discharging this as is may cause water pollution. Furthermore, if oil vapor enters the condensing chamber, the condensing tube bundle will be contaminated with oil and heat transfer will be significantly inhibited.

The mixing ratio of water and oil for oil-containing bilge water inside a ship or oil-containing factory waste water is the opposite of the above case, but
Even if this is separated by the above-mentioned device, if an oil component having a vapor pressure close to that of water is present, the condensed water will contain oil, which will be a problem. Another possible method is a distillation method (fractional distillation) in which an oil-water mixture is separated by the difference in vapor pressure between oil and water, but this method requires a distillation column and is not suitable for ordinary oil-containing wastewater treatment.

General oil-containing wastewater often contains surfactants, which form a stable emulsion, making it difficult to completely separate them using specific gravity separation or oil-water separation techniques using adsorbents.

However, if an oil-water mixture emulsified with a surfactant is evaporated, since the surfactant has almost no vapor pressure, only oil vapor and water vapor will exist in the vapor phase, and even if these vapors are condensed, The condensate does not emulsify again. Although it is possible to treat this condensate with a general oil-water separator using a specific gravity difference or an adsorbent, the device is complicated and requires a large installation area.

(Problem that the invention aims to solve) When oil-containing wastewater, such as bilge water in ship engine rooms and factory wastewater, is emulsified with surfactants, the emulsification is destroyed by heating, and the oil and water separate into two phases. However, since a surfactant is present, the separated oil and water will be re-emulsified if external stirring force or vibration is applied, such as by pumping after cooling.

(Means for solving the problem) In view of the above, the present invention employs a means to capture and remove oil contained in the gas phase during evaporation to prevent it from reaching the condenser. The gist of this is that the evaporation chamber and condensation chamber for the oil-water mixture, which are divided into sections in the casing, communicate with each other through a passage.
This is an evaporative oil-water separator comprising a mist separator on the upstream side of the passage and an adsorbent layer on the downstream side.

(Function) In the present invention, when an oil-water mixture is heated, oil vapor and water vapor are generated at a constant ratio so that the sum of the vapor pressure of oil and the vapor pressure of water becomes the total pressure of the vapor space. In particular, when the liquid surface of the oil-water mixture is covered with an oil film, the water causes a bumping phenomenon and splashes of water and oil are generated, which are removed using a mist separator.

The generated oil vapor is adsorbed by the adsorbent layer, and only the water vapor is led to the condensation chamber. Therefore, the condensing tube bundle is always kept clean and good heat transfer is maintained. The oil remains in the evaporation chamber as an unevaporated liquid and is discharged from the outlet.

The material of the adsorbent used in the adsorbent layer that removes oil vapor is preferably a lipophilic substance, and both inorganic and organic substances are widely available, and activated carbon, polypropylene cotton, etc. are particularly suitable because they are easily available. If the adsorption capacity of this adsorbent decreases due to long-term use, it can be replaced as appropriate or regenerated within the device.

(Embodiment) The figure is an explanatory cross-sectional view of one embodiment of the present invention, in which the casing 1 includes a vertical wall 4 provided at a distance of 3 from the ceiling plate 2, and a vertical wall 4 connected to the vertical wall 4 and extending to the casing side wall 5. By the extended horizontal bulkhead 6,
An evaporation chamber 7 and a condensation chamber 8 are partitioned, and both chambers communicate with each other through a passage 9, in which a mist separator 10 is provided on the upstream side of the vapor flow, and an adsorbent layer 11 is arranged on the downstream side. A lid 12 is attached to the casing by bolts or the like so that the adsorbent layer 11 can be replaced.

The mist separator 10 is made of, for example, densely packed wire mesh, and the adsorbent layer 11 is made of, for example, compressed polypropylene cotton, which has the property of adsorbing oil well.

A condensing tube bundle 13 through which a refrigerant flows is arranged in the condensing chamber 8, a condensed water outlet tube 14 opens at the bottom, and a bleed tube 15 communicates with an external vacuum device 16 such as a vacuum pump. The evaporation chamber 7 is provided with a heating tube bundle 17 through which a heat medium flows and is connected to an external heating source (not shown), and the casing is provided with an oil/water mixture introduction pipe 18 and an oil drain pipe 19.

In the evaporative oil-water separator constructed as described above, the oil-water mixture is introduced through the tube 18, heated by the heating tube bundle 17, and evaporated under vacuum. Water vapor and oil vapor pass through the mist separator 10, and if there are liquid particles, they are separated, and then pass through the adsorbent layer 11, which is lipophilic, so it adsorbs and separates the oil vapor, and only the water vapor enters the condensation chamber 8. It condenses and is taken out from the take-out pipe 14. The remaining unevaporated liquid is only oil, which is taken out from the oil drain pipe 19.

In the above explanation, the evaporation was carried out in a vacuum, but it is of course possible to carry out the evaporation in a place other than a vacuum.In the illustration, the condensation chamber 8 is provided on one side of the casing, but it is placed in the center and on both sides. The mist separator 10 and the adsorbent layer 11 may be arranged by providing a passage, and the oil/water mixture in the evaporation chamber 7 is heated by introducing a heating medium from the outside, but the present invention is not limited to this. The heated oil-water mixture can be introduced into the evaporation chamber to perform flash evaporation, or the oil-water mixture introduced into the evaporation chamber can be heated by directly blowing high-temperature exhaust gas from a boiler, heating furnace, etc., or steam. , various evaporation methods can be adopted.

(Effects) In this invention, when the oil-water mixture is evaporated and oil-water is separated, a mist separator is provided on the upstream side and a lipophilic adsorbent layer is provided on the downstream side in the steam passage in the casing, which makes it possible to evaporate the oil-water mixture and separate it from the oil-water mixture. Even when there is an oil component with a vapor pressure close to that of water, which would be difficult to separate, the device of this invention makes it easy to separate oil and water, and the mist separator prevents oil droplets from entering, allowing them to be adsorbed. Helps maintain the adsorption separation effect of materials.

Furthermore, since oil does not reach the condensing tube bundle, it is not contaminated with oil, and has the effect of maintaining good heat transfer over a long period of time.Since the adsorbent layer is built-in, the device is compact. In particular, in the treatment of bilge water in ships, this method, combined with the advantage of being able to use the high-temperature exhaust gas of the engine as a heating source, exhibits a remarkable effect.

[Brief explanation of the drawing]

The figure is an explanatory cross-sectional view of one embodiment of the present invention. 1... Casing, 7... Evaporation chamber, 8... Condensation chamber, 9... Passage, 10... Mist separator, 1
1...Adsorbent layer, 16...Vacuum device.

Claims (1)

[Scope of utility model registration request] An evaporative oil-water separator in which an evaporation chamber and a condensation chamber for an oil-water mixture partitioned in a casing are communicated by a passage, and a mist separator is provided on the upstream side of the passage and an adsorbent layer is provided on the downstream side of the passage.