JPH06277678A - Continuous high pressure oxidization device - Google Patents

Abstract

PURPOSE:To provide a device for oxidizing waste water such as the photograph development waste containing both of an inorganic substance and an organic substance mainly of heavy metals efficiently and at a low cost. CONSTITUTION:A first oxidization device 4 for wet oxidizing an inorganic substance without a catalyst and a second oxidization device 7 for oxidizing an organic substance under the presence of catalyst are used as high pressure reaction devices respectively, and a solid-liquid separation device 6 for removing cakes from the neighborhood of the first oxidization device 4 is connected to respective oxidization devices 4 and 7 by means of pipelines to operate the whole system under the pressurized state.

Description

Detailed Description of the Invention

[0001]

Industrial field The waste liquid may contain both a metal or a metal compound (hereinafter sometimes referred to as an inorganic substance) and an organic substance depending on its origin. The present invention relates to equipment for efficiently purifying waste liquid in such a case.

[0002]

2. Description of the Related Art Typical examples of waste liquid containing both inorganic and organic substances are chemical plant equipment, plating industry equipment, photographic processing equipment, leather manufacturing equipment, metal industrial equipment, metal mining equipment, food manufacturing equipment, Examples include waste liquids discharged from pharmaceutical manufacturing equipment, textile industrial equipment, paper pulp industrial equipment, dyeing dye industrial equipment, electronic industrial equipment, machine industrial equipment, printing plate making equipment, glass manufacturing equipment, and the like. However, these are merely representative examples, and it is apparent from the gist of the present invention described below that the application target of the present invention is not limited by these examples.

As the inorganic substance, Fe, Cr, C
o, Cu, Mn, Ag, Sn, Pb, Bi, Ni, Z
In addition to heavy metals represented by n, Cd, Hg, etc. or their compounds, there are light metals such as Al, Ca, Mg, Ti, etc., or their compounds. The organic substances include organic phosphorus compounds and organic halogens. There are compounds, organic silicon compounds, nitrogen-containing organic compounds and the like. The former must be purified, for example, from the viewpoint of toxicity, and the latter, for example, from the viewpoint of exhibiting a high COD value and being involved in environmental pollution.

Examples of the purification treatment technology include biological treatment method, combustion method, dry method of heating and evaporation, oxidation method using chlorine-based chemical agent, electrolytic oxidation method, hydrogen peroxide-ferrous iron salt method, ozone oxidation. Method, coagulation separation removal method by addition of inorganic or organic coagulant, adsorption separation separation method using activated carbon, inorganic adsorbent or organic polymer material, reverse osmosis method using membrane, electrodialysis method and ultrafiltration method Are known.

[0005]

However, the above-mentioned various methods are in great need of improvement as described below. For example, (1) biological treatment method, coagulation separation removal method, adsorption separation removal method, electrodialysis method, reverse osmosis membrane method, ultrafiltration method,
The hydrogen peroxide-ferrous iron salt method, the ozone oxidation method, etc. are difficult to carry out a purification treatment by themselves to a sufficient level. (2) Combustion method, dry solidification method, electrolytic oxidation method, ozone oxidation method Method, adsorption separation removal method, reverse osmosis membrane method, electrodialysis method, ultrafiltration method, etc. have high treatment costs, and (3) combustion method, dryness method, coagulation separation removal method, adsorption separation removal method, etc. There was a problem such as generation of substances that would later become secondary pollution.

The present inventors have long been concerned about the above-mentioned circumstances, and have researched a novel waste liquid treatment technology which does not have the above-mentioned drawbacks, and have completed the invention as described in Japanese Patent Application No. 4-348393. The content of the patent application invention is directed to photographic development waste liquid (hereinafter sometimes simply referred to as waste liquid). First, by performing non-catalytic wet oxidation treatment under high temperature and high pressure, mainly heavy metals in the waste liquid are insolubilized. Alternatively, it is difficult to solubilize and remove the formed metal compound by solid-liquid separation under normal pressure, and then return the filtrate to high temperature and high pressure again to carry out catalytic wet oxidation treatment to oxidize and decompose mainly organic substances in the waste liquid. Was to be.

By this method, it is possible to highly purify the waste liquid without the generation of substances that cause secondary pollution, and it is possible to operate at a relatively low cost and the maintainability of the equipment is good. Various effects were obtained.

However, when further research was continued after that, the pressure for solid-liquid separation was released at the time when the high-temperature high-pressure oxidation process for removing the inorganic substance was completed, and was again conducted for the next organic substance oxidation process. We recognized that there is a problem in terms of equipment cost and operating cost in terms of applying pressure.

The present invention has been made by paying attention to such a situation, and by solving the above inconvenience in facility cost and operating cost, the above-mentioned Japanese Patent Application No. 4-348393.
The invention is intended to be more effective. Further, the invention of the above-mentioned prior application was aimed at the development processing waste liquid of the photograph, but the subject of the present research is not limited to the development processing waste liquid, but a waste liquid containing both inorganic substances and organic substances. All are now applicable.

[0010]

The gist of the present invention is mainly to introduce a first oxidizing device for insolubilizing or sparingly insolubilizing the inorganic substance, and introducing a solid-containing liquid discharged from the first oxidizing device to solidify the inorganic substance. A first filtering device, a filtering device, and a second oxidizing device, each of which includes a filtering device for liquid separation, and a second oxidizing device that introduces a filtrate of the filtering device to oxidize or oxidatively decompose an organic substance mainly in the presence of a catalyst. Are connected by a pipeline, and the operation of each device is configured to be continuously operated under high pressure.

[0011]

The first oxidizing device for insolubilizing or hardly insolubilizing an inorganic substance may be a single-column type or a multi-column type, and the point is that it is carried out under high pressure as described above, but it is particularly preferable. Under the supply of gas that serves as an oxygen supply source,
A temperature of 370 ° C (more preferably 180 to 300 ° C),
And non-catalytic wet oxidation under a pressure at which the processing waste liquid retains a liquid phase. By the above reaction in the first oxidation device (hereinafter sometimes referred to as the first oxidation step), silver, iron,
Inorganic substances such as aluminum produce water-insoluble or sparingly soluble solid substances (sometimes represented by a scale in this specification) such as oxides, hydroxides and inorganic salts, and are precipitated from the waste liquid. In addition to silver being deposited as silver chloride, silver may be deposited in a state of being adsorbed by an insolubilized compound or the like. In addition, elements other than the above, such as phosphorus, silicon, calcium, magnesium, etc., are also converted into water-insoluble or sparingly soluble substances,
Or, it is adsorbed and deposited on other deposited scales, but since these elements are substances that can become catalyst poisons to the catalyst used in the second oxidation step to be described later, these elements are used in this first oxidation step and the following Removal by the high-pressure filtration device is evaluated as a purposeful phenomenon which is regarded as positioning in the whole system of the present invention.

The solid matter produced in the first oxidation step is supplied to the filtration device through the pipeline without pressure release, that is, in the state where the high temperature and high pressure are maintained. Therefore, the operating temperature and pressure in the filtration process are substantially the same as those in the first oxidation process, but some control is performed in consideration of a slight temperature decrease due to heat dissipation, or a pressure loss in the transfer process or the solid-liquid separation chamber. The configuration with an additional device that can perform
Both are included in the present invention.

The filtration method adopted in the filtration device is as follows:
A leaf filter system, a Schenk filter system, a Nutsche system, a filter press system, etc. are mentioned. The filtration pressure, 8-250Kg / cm ² · G at a total pressure, preferably 8-100Kg / cm ² · G (The differential pressure 1-7Kg / cm ² · G, particularly preferred is 5Kg / cm ² · Drive around G). Further, in order to control the pressures of the first oxidation device and the second oxidation device to be constant, it is necessary to absorb the differential pressure on the secondary side of the filter.
It is desired to install C.

Regarding the filter cloth, nylon, polyester, polypropylene, acrylic resin, saran, fluorocarbon, rayon, glass fiber felt, wire mesh, various porous filter bodies, etc. are most suitable in consideration of operating temperature and operating pressure. It is desirable to selectively use. Further, depending on the particle size, it is preferable to perform precoating or body feeding using a filter aid. For example, when the particle size is 2 μm or less, precoating, or precoating and body feeding is performed, and when the particle size is 2 to 50 μm, filtration is performed as it is, or the same procedure as when the particle size is 2 μm or less. On the other hand, when it exceeds 50 μm, it is recommended to carry out filtration as it is, and to carry out filtration so as to suppress SS component to several ppm or less at the outlet.

The filtrate discharged from the filtration device under the conditions of high temperature and high pressure, at least high pressure, is supplied to the second oxidation device through a pipeline, and mainly organic substances are oxidized or oxidatively decomposed. This oxidation or oxidative decomposition is a catalytic reaction under high temperature and high pressure, and preferably 140 to 370 ° C. (more preferably 1 ° C.) under the supply of a gas serving as an oxygen supply source.
(80 to 300 ° C.) and the pressure at which the processing waste liquid retains the liquid phase. The second oxidizer does not matter whether it is a single-column type or a multi-column type.

The two-step oxidation process of the present invention will be described in more detail below. First, regarding the non-catalyst wet oxidation step (first oxidation step) in the first oxidation device, when the inorganic substance in the treatment waste liquid forms a compound with the organic substance and is dissolved in the treatment waste liquid, the treatment waste liquid is treated. Since the organic substance therein may be simultaneously oxidized or oxidatively decomposed during the first oxidation step, it is particularly effective for removing inorganic substances and organic substances from the treatment waste liquid. That is, when the inorganic substance, the organic substance, and the like are dissolved in the treatment waste liquid as, for example, a chelate complex, the chelating agent is decomposed in the first oxidation step, and the inorganic substance is liberated. Therefore, the inorganic substance, etc.
A solid substance that is insoluble or sparingly soluble in water is likely to be deposited and is easily removed. It is also possible to fill the first oxidation reaction tower with a filler such as metal or ceramic to improve stirring of liquid and gas.

Next, the catalyst used in the second oxidation step is
Any catalyst may be used as long as it is a solid catalyst and has both activity and durability under the conditions of liquid phase oxidation, for example, titanium, iron, aluminum, silicon, zirconium or activated carbon is contained. Examples of the catalysts include oxides such as titanium, titanium-zirconium, and titanium-iron. These catalysts may contain a second component in addition to the above components (hereinafter referred to as the first component).

The second component is at least one metal such as manganese, cobalt, nickel, tungsten, copper, cerium, silver, platinum, palladium, rhodium, gold, iridium or ruthenium, or a component thereof. Can be used. This catalyst is the first
For the component 75 to 99.95% by weight, the second component 25 to
The ratio is preferably 0.05% by weight. In addition, various shapes of the catalyst can be adopted and are not particularly limited.

An adsorption tower filled with an inorganic adsorbent may be provided in front of the second oxidation reaction tower to prevent poisoning of the catalyst due to an inorganic substance which is not sufficiently removed. The inorganic adsorbent is not particularly limited, but is preferably an oxide containing titanium such as titanium, titanium-zirconium, or titanium-iron.

The treatment amount of the waste liquid in the first acid step can be increased when the treatment temperature is high, and conversely, it is small when the treatment temperature is low. Processing temperature 2 as an example
In the case of 70 ° C., the space velocity is 0.5 / hr to 5 /
hr is preferred. When the processing temperature is 180 ° C, 0.1 /
hr to 1 / hr is preferable. Space velocity 5 / h at 270 ° C
If it exceeds r or exceeds 180 ° C and the space velocity exceeds 1 / hr, the treatment efficiency decreases, and conversely, if the space velocity is less than 0.5 / hr at 270 ° C and the space velocity is 0.1 / hr at 180 ° C. If it is less than the above range, the amount of waste liquid to be treated decreases, the equipment becomes excessive, and the reaction efficiency exceeds the appropriate range, which is not preferable.

Therefore, the higher the treatment temperature is, the better the treatment efficiency is, and the treatment speed can be increased, so that the reactor can be downsized, but the treatment pressure becomes high, which makes maintenance difficult and COD in the wastewater. When the concentration is low, it becomes difficult to maintain the temperature in self-sustaining operation. On the other hand, when the processing temperature is low, the processing efficiency is low, but the processing pressure is low, which facilitates maintenance and the like. Further, if the treatment efficiency of the COD component is increased more than necessary in the first oxidation step, the heat source for maintaining the temperature in the second oxidation step and performing the self-sustaining operation becomes insufficient. For this reason, in the first oxidation step, it is preferable to suppress the COD treatment efficiency to such an extent that the generated solid matter and the like are sufficiently precipitated and can be sufficiently separated and removed by the filtration device. The treatment efficiency of the COD component in the first oxidation step is not particularly limited and may be appropriately selected depending on the case, but is generally 20%.
~ 80%.

The amount of processing liquid supplied to the second oxidation step is
When the processing temperature is high, the number can be increased, and conversely, when the processing temperature is low, the number can be decreased. Generally, the space velocity is 0.1 / hr to 5 / hr, and more preferably 0.5 / hr to 3 / hr. This is because when the space velocity exceeds 5 / hr, the processing efficiency decreases, and when the space velocity is less than 0.1 / hr, the processing amount decreases and the equipment becomes excessive.

The oxygen supply source gas (hereinafter sometimes referred to as oxidizing gas) in the present invention means a gas containing oxygen or ozone. When a gas such as ozone or oxygen is used, it can be appropriately diluted with an inert gas or the like before use. Air is preferably used, but in addition to these gases, oxygen-containing waste gas generated from other plants can also be appropriately used.

The amount of oxidizing gas used in the first oxidation step can be appropriately selected depending on the concentration of the treatment waste liquid.
In this case, it is 0.5 to 5 times, more preferably 1.0 to 3 times, the amount of oxygen required to completely decompose the COD component of the treatment waste liquid to water, carbon dioxide gas, inorganic salts, and other ash. . When it exceeds 5 times, it becomes unnecessary supply of oxygen,
If it is less than 0.5 times, the amount of oxygen required is not sufficient and purification of the processing waste liquid is incomplete. 0.5 to 1.0
The double range is a shortage of oxygen amount, but it is one of the effective means when it is desired to secure the COD in the second oxidation step which is the next treatment.

The oxidizing gas used in the second oxidation step is, as described above, 0.5 to 3 times the required amount of oxygen, more preferably,
It is 1.0 to 2 times. When it exceeds 3 times, the oxygen is excessively supplied, and when it is less than 0.5 times, the required amount of oxygen is insufficient and the purification of the treatment waste liquid becomes incomplete. In the range of 0.5 to 1 times, the COD component of wastewater is completely water,
The amount of oxygen required for conversion to carbon dioxide, inorganic salts, and other ash is also insufficient. The reason for this is that the processing efficiency of COD is usually less than 100%, so that the supplied oxygen finally remains unused at 100%, and in such a case the amount of oxygen supplied should be adjusted to 1% according to the actual processing efficiency. This is because the processing efficiency of COD does not deteriorate so much even if it is less than twice.

In the filtration device, it is effective to add a coagulant, a coagulant aid and the like as necessary to increase the processing speed and the separation efficiency. As the coagulant and the coagulant aid, conventionally known ones can be used and are not particularly limited, but the water-soluble inorganic coagulant aid causes catalyst poisoning in the next second oxidation step. In some cases, use is often limited, and therefore it is preferable to use an organic polymer flocculant. Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these descriptions.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing the overall concept of the equipment of the present invention, in which a waste liquid such as a photographic development processing liquid is put in a raw water tank 1 and is pumped through a line A by a pump P ₁ .
It is supplied to the oxidizer 4. Since the high-pressure air pressurized and supplied by the air compressor 11 is pressed into the line A from the air holder 3 through the line B, the waste liquid is mixed with the high-pressure air to form a high-pressure gas-liquid mixture, and the heat exchanger 2a. After being heated by, it is introduced into the first oxidation device 4.

The high-temperature oxidation reaction product produced in the first oxidizer 4 reaches the heat exchanger 2a from the line C, and the line A
It is introduced into the gas-liquid separator 5 after being used for heating the high pressure gas-liquid mixture coming from it. In the gas-liquid separator 5, the liquid level controller LIC detects the liquid level and the liquid level control valve V ₂
Keeps the liquid level in the gas-liquid separator 5 constant, detects the pressure of the gas-liquid separator 5 by the pressure controller PIC, and keeps the pressure in the gas-liquid separator 5 constant by the pressure control valve V ₁ . To do.

The non-catalyst wet-oxidized liquid that has passed through the liquid level control valve V ₂ and is transferred through the line D is introduced into the solid-liquid separation device (for example, filtration device) 6 while maintaining a high pressure state. . The precoating agent is contained in the precoating tank 9. The precoating agent, which is kept in a uniformly dispersed state by the precoating stirrer 13, is sent out through the line K, merges with the line D, and then is introduced into the filtering device 6. The structure is adopted. This is for supplying a pre-coating agent to the filter cloth surface of the filtering device 6 to enhance the filtering effect at the initial stage of filtering. The precoating liquid after the precoating process is returned to the precoat tank 9 through the line J. The line O is provided for removing air from the filter.

The high-pressure filtrate that has passed through the filtration device 6 enters the line E, and if necessary, the heater 12, the control valve V ₃ , the heat exchanger 2b, and the second oxidation device 7.
And high pressure wet oxidation is performed in the presence of a catalyst. The oxidation product reaches the heat exchanger 2b from the line F, and the line E
Heater 2c which is provided if necessary after heating the liquid
It is further cooled by and enters the gas-liquid separator 8. The gas components separated in the gas-liquid separator 8 (the gas generated by the oxidative decomposition of the organic substance and the surplus air) are released into the atmosphere through the line G (after further processing if necessary), while the liquid The components are released to the outside of the system via line H (after further treatment if necessary).

The control valve V ₃ in the line E is for adjusting the opening by measuring the pressure on the outlet side of the filtering device 6 by the pressure controller PIC. A back pressure is applied to detect the state that the filtration resistance on the surface of the filter cloth has increased due to the progress of filtration, and gradually opens the throttle, which alleviates the pressure fluctuation in the entire filtration process. , Stable operation under constant pressure is guaranteed.

As described above, the first oxidation, the solid-liquid separation, the second
Although each process of oxidation is continuously performed, when the amount of cake on the entire surface of the filter cloth in the filtering device 6 increases, it is necessary to take out this cake, and normally, the liquid level control valve V ₂ and From the state in which the control valve V ₃ of the line E is closed and the oxidizing devices 4 and 7 on both sides are maintained at high pressure, the valve V ₆ is opened and the filtrate is returned to the raw water tank 1 via the line M so that the inside of the filtration device 6 is kept at a constant temperature. It is desirable to carry out an operation such that the pressure is set, then the valve V ₅ is opened to introduce the outside air, the cake in the filtration device 6 is dried, and then the cake discharge valve V ₄ is opened to discharge the cake. In this process, the pressure of the filtration device 6 is released to the atmospheric pressure, so the cake discharge valve V ₄ is closed and pressurized air is supplied from the line N, and the inside of the filtration device 6 is supplied with the oxidizing devices 4, 7 Increase pressure until it matches the internal pressure.

When the filtration device 6 is restarted, the filtration device 6
If the internal temperature is raised, it becomes possible to maintain the temperature of the waste liquid from the first oxidizing device toward the second oxidizing device at a preferable operating temperature. Therefore, in the equipment of FIG. 1, a structure is provided in which a filtrate discharge line L of the filtration device 6 is provided, and part or all of the filtrate at the time of restarting filtration is introduced to the discharge line L, heated by the heater 10 and then returned to the filtration device 6. It is adopted. This facilitates maintaining the pressure of each oxidation step at a predetermined pressure. As another method, instead of the heater 10, the outlet side heater 12 can directly raise the temperature.

In the above embodiment, one filter device 6 is provided, but if two or more filter devices are provided and they are operated alternately, the first oxidation process, the solid-liquid separation process and the second oxidation process are performed. Can be a more reliable continuous operation without interruption.

[0035]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, the first oxidation step centered on the insolubilization of heavy metals, the filtration of the cake produced thereby, and the second oxidation step centered on the oxidation of organic substances. Can be operated under continuous pressure. Therefore, it has become possible to reliably treat waste liquid containing inorganic substances such as heavy metals and organic substances at low cost and high efficiency.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an embodiment of the present invention.

[Explanation of symbols]

 1 Raw Water Tank 2 Heat Exchanger 3 Air Holder 4 First Oxidizer 5 Gas-Liquid Separator 6 Solid-Liquid Separator (Filtration Device) 7 Second Oxidizer 8 Gas-Liquid Separator 9 Precoat Tank 10 Heater 11 Air Compressor 12 Heater 13 Precoat agitator 14 Precoat pump 15 Filter starter circulation pump 16 Drying air blower

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kiichiro Mitsui 1 992 Nishikioki, Kamahama, Aboshi-ku, Himeji-shi, Hyogo 1 Japan Catalysis and Catalysis Research Institute Co., Ltd.

Claims (1)

[Claims] 1. A facility for oxidizing a waste liquid containing a metal or a metal compound and an organic substance, wherein the first oxidation device mainly treats the metal or the metal compound to make it insoluble or hardly soluble in the waste liquid, A filtering device for introducing a solid-containing liquid discharged from the first oxidizing device to perform solid-liquid separation, and a second oxidizing device for introducing a filtrate of the filtering device to oxidize or oxidatively decompose an organic substance mainly in the presence of a catalyst. A continuous high pressure system comprising a device, wherein the first oxidation device, the filtration device and the second oxidation device are connected by a pipeline, and each device is operated by continuous operation under high pressure. Oxidation treatment equipment.