JP2001293104A - Method of turning polychlorinated biphenyl oil to resource - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method to make polychlorinated biphenyl (PCB) harmless by a 2-step treatment to produce a reaction product usable as a material. SOLUTION: A chemical decomposing process, a granulating process, and a thermal decomposing process are orderly executed in this method. The chemical decomposing process is to decompose PCB oil b into powder e containing a metal salt using a decomposing action and an exothermic reaction of Ca, the main component of a decomposing agent a. The granulating process is to solidify the powder e produced by the chemical decomposing process into pellets i. The thermal decomposing process is to melt the pellets i and glass cullet j under a temperature over the thermal decomposing point of PCB into slug k to melt and unify pellets i and glass cullet j. Slug k obtained in the thermal decomposing process is cooled down into a solid material l which is crushed to be recycled as a building material, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for recycling polychlorinated biphenyl oil (PCB) into a useful resource as a starting material.

[0002]

2. Description of the Related Art Polychlorinated biphenyl oil (hereinafter referred to as PCB)
) Has various properties depending on the number and position of chlorine contained in biphenyl, but is generally used as a heat carrier or insulating oil because of its excellent physical properties and chemical stability.

[0003] However, when PCBs are taken into the body, they are slowly decomposed, remain for a long time, and exhibit toxicity. PCB
Although it is not currently produced, it was once widely used for electrical insulating oil of transformers and other equipment,
It can be said that the collection, disposal, and disposal of existing equipment using PCBs, as well as the treatment, collection, and disposal of PCBs that have leaked to the environment, have just begun.

[0004]

A typical disposal method of PCB is incineration. Not only PCB but also many harmful chemical substances can be decomposed and made harmless by incineration. However, during incineration, new harmful substances such as dioxin may be generated during incineration, and the establishment of high-temperature combustion treatment technology is required.However, in Japan, there are concerns about the effects of the surrounding environment. The fact is that the location of incineration facilities has not been realized.

[0005] Regarding the detoxification technology of PCB, for example, a method called “chemical extraction decomposition method” is available on an Internet homepage (Press Release of Tokyo Electric Power Company, Inc.)
"Development of PCB detoxification technology"
(February 2) (Prior example 1). In the method of the prior art example 1, a solvent is added to insulating oil containing PCB to activate chlorine (Cl) of the PCB and to add sodium hydroxide (NaO).
H) to replace PCB with completely harmless salt (NaCl) and biphenyl.

[0006] According to this method:-Insulation oil of low concentration (about 0.02%) to high concentration (about 70%), which can be treated in a closed facility and has no influence on the race between surrounding areas For any of the PCBs inside,
For the first time, high decomposition performance that can be applied to the actual treatment level was confirmed.-The chemical reaction is safe under the condition of about 200 ° C and normal pressure.-No harmful substances are generated in the reaction. It emphasizes the effect that harmless insulating oil and salt remain after the treatment and can be reused as fuel oil or recycled insulating oil.

[0007] Indeed, this technology is considered to be an excellent concept in that not only the PCB is made harmless but also the reaction product can be reused as a resource. Although the entire contents of the “chemical extraction decomposition method” are not clear from the above disclosure content alone, it is thought that, in short, it is intended to realize detoxification of PCBs only by chemical reaction.

[0008] In general, there is a problem that it is not always guaranteed that 100% chemical change is caused only by a chemical reaction. For example, even if the amount of the remaining PCB satisfies the safety standard, the problem that the PCB remains does not solve the problem.

An object of the present invention is to provide a two-stage process,
An object of the present invention is to provide a method for recycling polychlorinated biphenyl oil, which renders CB harmless and generates a reaction product usable as a resource.

[0010]

In order to achieve the above object, a method for recycling polychlorinated biphenyl oil according to the present invention is a method for recycling polychlorinated biphenyl oil by a two-stage treatment of a first-stage treatment and a second-stage treatment. In the first-stage treatment, a polychlorinated biphenyl oil is chemically changed to produce a powder containing a metal salt, and then the powder is pelletized. This is a process of melting and integrating by heat treatment at a temperature equal to or higher than the thermal decomposition temperature, and utilizes a solid obtained by cooling the melt and integrated slag as a resource.

The present invention also provides a method of recycling PCB oil, which comprises a chemical decomposition treatment, a granulation treatment, and a thermal decomposition treatment, wherein the chemical decomposition treatment uses a polychlorinated biphenyl utilizing the decomposition action of CaO and an exothermic reaction. The process of breaking down oil into powder containing a metal salt, the granulation process is a process of solidifying the powder generated by the chemical decomposition process into pellets, and the pyrolysis process is a process of pelletizing the powder generated by the granulation process. And glass cullet are melted at a temperature equal to or higher than the thermal decomposition temperature of the PCB, and the pellets and glass cullet are melted and integrated as slag. The slag obtained by the thermal decomposition treatment is reused as a solid after cooling. Is what is done.

In the chemical decomposition treatment, PCB oil is mixed with calcium oxide powder, water is further added, and the PCB oil is decomposed by the exothermic reaction of calcium oxide. Is generated.

[0013] The thermal decomposition treatment is a treatment for thermally decomposing a PCB oil component which may remain in the powder produced by the chemical decomposition treatment.

The pyrolysis process is performed in a melting furnace using coke as fuel, and the pellets generated by the granulation process also serve for adjusting the basicity to be charged into the melting furnace.

[0015] Further, the present invention provides a method for recycling PCB oil, which comprises a chemical decomposition treatment, a granulation treatment, and a thermal decomposition treatment, wherein the chemical decomposition treatment changes the PCB oil into powder containing a metal salt. The thermal decomposition treatment is a treatment for preventing the working environment from being contaminated by PCB oil during the thermal decomposition treatment. The granulation treatment is a process in which the powder generated by the chemical decomposition treatment is processed into pellets as a pre-treatment of the thermal decomposition treatment, and the powder is processed. This is a process that prevents scattering and facilitates handling during the pyrolysis process.The pyrolysis process involves putting the pellets obtained by the pelletization process together with the glass cullet into a melting furnace using coke as fuel, In this process, the pellets are fused at a temperature higher than the thermal decomposition temperature of the PCB, the pellets are melted and integrated with the glass, and the resulting slag is reused as a solid after cooling. It is intended to be.

According to the present invention, PCB oil is rendered harmless by a two-stage treatment, and a by-product of recyclable products is produced. The first-stage process is a chemical decomposition process and a granulation process, and the second-stage process is a thermal decomposition process.

The chemical decomposition treatment is a treatment for producing a powder containing a metal salt by chemically changing PCB oil. The work environment of the post-treatment is prevented from being contaminated by the PCB oil.
In addition, by subjecting the generated powder to a pelletizing treatment, scattering to the environment is prevented during the thermal decomposition treatment, and handling is facilitated.

The post-treatment is a treatment for thermally decomposing the pellets, and is a treatment for fusing and integrating with the glass cullet. The slag produced by melting and integrating the pellets and the glass carat becomes a glossy granite-like solid by cooling the slag. The solid can be used as a resource by grinding or cutting into a required shape.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. In the present invention, the chemical decomposition treatment performed as the pretreatment is, specifically, a treatment for decomposing PCB oil into a powder containing a metal salt by utilizing the decomposing action of CaO and heat of reaction. This is a process for generating an eluted powder.

For the chemical decomposition treatment, a decomposition treatment agent mainly composed of calcium oxide (CaO) powder whose surface is coated with vegetable oil is used. Commercially available calcium oxide (Ca
O) contains a small amount of NaC, Mg, K, etc.
O ₃ , MgCO ₃ , and KCO ₃ may be contained in some cases, and these components can be effectively used together with CaO in the chemical reaction of PCB.

The vegetable oil which coats the surface of CaO is for suppressing the rapid exothermic reaction of CaO, and the amount added to CaO is in the range of 1 to 3%.
If the amount of the vegetable oil added exceeds 3% and is too large, the exothermic reaction of CaO is hindered. Conversely, if it is less than 1%, the rapid exothermic reaction cannot be suppressed.

In FIG. 1, a PCB oil b is sufficiently mixed with a decomposition agent a mainly composed of calcium oxide (CaO) powder coated on the surface with vegetable oil,
Thereafter, water (H ₂ O) c is added. With the addition of water c, CaO coated on the surface with vegetable oil reacts with water, and the reaction of CaO + H ₂ O = Ca (OH) ₂ progresses slowly, and under an exothermic temperature of 100 ° C. to 250 ° C. In P
The CB oil b is decomposed and combined with the separated chlorine (Cl) to form a powder d in which PCB is not eluted.

When MgO is contained in the decomposition treatment agent, it becomes Mg (OH) ₂ and generates heat. Then, Ca
(OH) ₂ absorbs CO ₂ in the atmosphere to cause a carbonation reaction, and finally, Ca (O), which is hydrophobic calcium,
H) A reacted powder e containing ₂ and salt NaCl is obtained.

In the decomposition treating agent a, in addition to CaO, N
When a, Mg, K, etc. are contained in the form of NaCO ₃ , MgCO ₃ , KCO ₃ , Na, Mg, K, Ca become C
1 and these become powder containing MgCl, KCl and CaCl, and the decomposition of PCB is completed.

The powder e thus produced is then added with cement f for granulation, kneaded with an appropriate amount of water g and solidified, and the solidified product h is pelletized to an appropriate size. i
Process into The reason why the powder generated by the chemical decomposition treatment is processed into pellets i is to prevent the generation of dust due to scattering of the powder in the subsequent thermal decomposition treatment, and the size is not a problem.

The thermal decomposition treatment, which is performed as a post-stage treatment, is a treatment in which the pellet i and the glass cullet j obtained by the granulation treatment are heat-treated in a melting furnace at a temperature equal to or higher than the thermal decomposition temperature of the PCB to be melted and integrated. It is. Pyrolysis treatment is
It is preferably performed in a melting furnace using coke as fuel.

The pellet i and the glass cullet j are charged into a melting furnace, and the oxygen-enriched high-temperature air is injected into the coke filled in the melting furnace from the tuyere.
A high temperature of 800 ° C. is obtained and the mixture of pellets i and glass cullet j is allowed to stay in the coke packed bed for a relatively long time to completely remove any PCB oil components that may remain in the powder produced by the chemical decomposition treatment. To form a slug k in which the pellet and the glass cullet are melted and integrated.

In the case of using a melting furnace using coke as a fuel in the pyrolysis treatment, the pellets produced by the granulation treatment contain limestone, and also serve for adjusting the basicity to be put into the melting furnace. In other words, there is no need to add limestone again.

The obtained slug k is taken out of the furnace and cooled to form a glossy granite-like solid l. The obtained solid material l is crushed into slug crushed stone m and reused as construction aggregate or as gravel laid on roads. In addition, solid materials are cut out into fixed forms and used for tiles, decorative boards, etc. it can.

[0030]

Embodiments of the present invention will be described below. FIG.
In (a), 50 kg of a decomposition agent a mainly composed of calcium oxide (CaO) powder whose surface is coated with vegetable oil is charged into a sealed mixer (eg, Henschel mixer) 1 to form a layer of the decomposition agent a. A recess a1 was formed in the center of the, and 50 liters of transformer oil b containing PCB was charged into the recess a1 (FIG. 2B).

Next, the lid 2 of the mixer 1 was closed, and the stirring blade 3 was rotated at a high speed to uniformly stir and mix the decomposition agent a and the trans oil b (FIG. 2C). Next, the rotation of the stirring blade 3 was stopped, the lid 2 was opened, and water c containing the surfactant was injected into the 20 liter mixer 1 (FIG. 3).
(D)).

Thereafter, the lid 2 of the mixer 1 is closed, the mixer 1 is sealed, and the stirring blade 3 is again rotated at a high speed to stir and mix the decomposition agent a and the trans oil b for 1 minute (FIG. 3 (e). )). Subsequently, while rotating the stirring blade 3, the on-off valve 4 provided at the bottom of the mixer 1 was opened, and the powder d as a mixture of the decomposition agent and the trans oil was taken out into the stainless steel vat 5 (FIG. 3 (f) )).

From the powder d of the mixture in the pad 5, water vapor began to evolve over time, indicating that a hydration reaction had occurred in the mixture. The temperature change lasts for about 60 minutes, and after a lapse of about 30 minutes, the maximum temperature is about 250 ° C.
(230 ° C. to 260 ° C.) (FIG. 4 (g)). When the water vapor generated from the mixture was analyzed, all the water was evaporated water due to the evaporation of water, and no PCB was detected.

Thereafter, the reaction was stopped, and powder e, which was a reaction product of the decomposition agent and the trans oil, was obtained in the vat 5 (FIG. 4 (h)). Next, as a granulation treatment, the obtained powder is put into a mixer 1, water g and cement f are added, and the mixture is stirred and kneaded (FIG. 4 (i)), and the kneaded material obtained in the mixer 1 is molded. It was poured into the frame 6 and the surface was flattened (FIG. 4 (j)). The kneaded material poured into the mold 6 was cured for a certain period of time and solidified (FIG. 4 (k)).

The obtained solidified product h was released from the mold 6 and crushed by a crusher into pellets 1 to 3 cm in size. The obtained pellet i and glass cullet (dust glass such as colored glass) j are put into a melting furnace 7, and coke 8 is used as fuel, and oxygen-enriched air 9 is sent into the furnace.
The mixture of the pellets and the glass cullet was exposed and melted at a high temperature of 700 ° C. to 1800 ° C., and the slag k was discharged from a gate into a pallet cooled with cooling water 10 (FIG. 5 (l)).

The slag was cooled and solidified in the pallet 11. Next, the obtained solid l was crushed into a crushed stone by a crusher (FIG. 5 (m)), and the slag crushed stone m obtained by the crushing was finally sieved to adjust the particle size and stored in a stack yard (FIG. 5). 5 (n)). Regarding the criteria for effective use of slug crushed stone, dioxins were below the detection limit. Of course, heavy metals were below the soil environmental standards.

The obtained slag crushed stone is used as materials for civil engineering materials (roadbed materials, asphalt aggregates, etc.), construction materials (concrete aggregates, tiles, etc.), ornaments, etc. (artificial stones, vases, teacups, flower pots, etc.). Can be used.

[0038]

As described above, according to the present invention, a large amount of processing can be basically performed by a two-stage processing of a first-stage treatment by a chemical treatment and a second-stage treatment by a heat treatment. Since the components contained are thermally decomposed, PCBs contained in transformer oil and the like are decomposed and made harmless, and the solid by-product can be effectively used as a raw material for building materials.

In particular, in the present invention, the powder produced by the chemical decomposition treatment is solidified into pellets by the granulation treatment, so that the PCB which may remain in the powder during the thermal decomposition treatment is not scattered. The working environment of a certain pyrolysis treatment is not contaminated and handling can be facilitated.

When a melting furnace using coke as a fuel is used for the pyrolysis treatment, the pellets produced by the granulation treatment are also charged with limestone again in the melting furnace because they also serve for adjusting the basicity to be charged. You don't have to. In the pyrolysis treatment, together with the pellets,
By using a crushed colored glass bottle as the glass cullet to be dropped into the melting furnace, there is also an effect that the colored glass bottle that has been conventionally difficult to regenerate can be treated.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a reaction in a method for recycling PCB oil of the present invention.

FIGS. 2 (a) to 2 (c) are views showing processing steps of a method for recycling PCB oil in the present invention in the order of steps.

FIGS. 3 (d) to 3 (f) are views showing processing steps of a method for recycling PCB oil in the present invention in the order of steps.

FIGS. 4 (g) to (k) are diagrams showing processing steps of a method for recycling PCB oil in the present invention in the order of steps.

FIGS. 5 (l) to (n) are diagrams showing the processing steps of the method for recycling PCB oil in the present invention in the order of steps.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mixer 2 Lid 3 Stirring blade 4 On-off valve 5 Butt 6 Pallet 7 Melting furnace 8 Fuel (coke) 9 Oxygen-enriched air 10 Mold 11 Pallet a Decomposition agent b PCB oil c Water d Powder e Reacted powder f Cement g Water h solidified matter i pellet j glass cullet k slag l solid matter m broken stone

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuhiro Kaizuka 1-62-406, Kameido, Koto-ku, Tokyo (72) Inventor Ryoji Watanabe 2-4-10-101 Kuwano, Koriyama-shi, Fukushima Prefecture (72) Inventor Juntaro Yoshioka 23F, Hirao Jousuicho, Chuo-ku, Fukuoka, Fukuoka F-term (reference) 2E191 BA13 BC02 BD01 BD11 4H006 AA05 AC13 AC26 BC10 BE11 EA22

Claims (6)

[Claims] 1. A method of recycling polychlorinated biphenyl oil by performing a two-stage treatment of a first-stage treatment and a second-stage treatment, wherein the first-stage treatment chemically converts the polychlorinated biphenyl oil into powder containing a metal salt. Generated and pelletized the powder, the latter process is a process of heat treatment of the pellets together with the glass cullet at a temperature equal to or higher than the thermal decomposition temperature of polychlorinated biphenyl to melt and integrate the slag. A method for recycling polychlorinated biphenyl oil, characterized by utilizing solids obtained by cooling the polychlorinated biphenyl oil as resources. 2. A method for recycling polychlorinated biphenyl oil, comprising a chemical decomposition treatment, a granulation treatment, and a thermal decomposition treatment, wherein the chemical decomposition treatment utilizes a decomposition effect of CaO and an exothermic reaction. The process of decomposing biphenyl chloride oil into powder containing a metal salt, the granulation process is a process of solidifying the powder generated by the chemical decomposition process into pellets, and the thermal decomposition process is a process generated by the granulation process. This is a process in which the pellets and the glass cullet are thermally melted at a temperature equal to or higher than the thermal decomposition temperature of polychlorinated biphenyl, and the pellets and the glass cullet are melted and integrated as a slag. A method for recycling polychlorinated biphenyl oil, characterized by being reused as a product. 3. The chemical decomposition treatment comprises mixing calcium chloride powder with polychlorinated biphenyl oil, further adding water, and decomposing the polychlorinated biphenyl oil by an exothermic reaction of calcium oxide. 3. The method for recycling polychlorinated biphenyl oil according to claim 2, wherein the process is a process of generating undissolved powder. 4. The polychlorinated product according to claim 2, wherein the pyrolysis process is a process for thermally decomposing a polychlorinated biphenyl oil component that may remain in the powder produced by the chemical decomposition process. How to recycle biphenyl oil. 5. The pyrolysis treatment is performed in a melting furnace using coke as a fuel, and the pellets generated by the granulation treatment also serve to adjust the basicity to be charged into the melting furnace. The method for recycling polychlorinated biphenyl oil according to claim 2. 6. A method for recycling polychlorinated biphenyl oil, comprising a chemical decomposition treatment, a granulation treatment, and a thermal decomposition treatment, wherein the chemical decomposition treatment chemically transforms the polychlorinated biphenyl oil to convert a metal salt. This is a process that protects the working environment from contamination of polychlorinated biphenyl oil during the pyrolysis process.The granulation process processes the powder generated by the chemical decomposition process into pellets as a pretreatment for the pyrolysis process. This is a process that prevents the powder from scattering and facilitates its handling during the pyrolysis process.The pyrolysis process puts the pellets obtained by the pelletization process together with the glass cullet into a melting furnace that uses coke as fuel. This is a process of fusing at a temperature equal to or higher than the thermal decomposition temperature of polychlorinated biphenyl in a melting furnace. A method for recycling polychlorinated biphenyl oil, wherein slag is reused as a solid after cooling.