JP2021037483A - Method for manufacturing water purification material - Google Patents

Abstract

To provide a method for producing a water purification material that purifies oily water such as produced water.SOLUTION: Reduction firing comprises the following first to sixth steps. First step: Wood section clay and plant-derived organic matter are kneaded and molded by adding water. Second step: The kneaded molded product is set in a furnace and heated at 300°C or lower to remove water in the molded product. Third step: The molded product from which water has been removed is held at 400 to 500°C and completely carbonized. Fourth step: A firing temperature is raised to 750 to 850°C, and by maintaining this temperature, bases and nitrates in the wood section clay are gasified to form continuous pores. Fifth step: The temperature is raised to 1050°C, an environment inside the furnace is set in a reduced state, and the continuous pore surface is vitrified. Sixth step: In the reduced state, the temperature is raised to 1250 to 1300°C, and by maintaining this temperature, quartz, alumina and metal are welded to the vitrified portion to activate the pore surface.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing a purifying material for purifying oil-containing water such as produced water.

Oil production is being restored by a water attack method in which water is injected into an oil well. Produce water is the water used in the water attack method and is a technical term used in the oil industry. This produced water contains not only oil and gas, but also heavy metals and trace amounts of naturally occurring radioactive substances, so it cannot be discarded as it is in rivers and the sea.

Prior arts using porous ceramic as a water purifying material include Patent Documents 1 to 3.
In Patent Document 1, two or more kinds selected from clay / silicate and aluminum hydroxide, for example, clay and silicate are used as a base material, and aluminum hydroxide is used as a base material in a mixture or a mixture of clay and silicate as a material for forming bubbles. Disclosed are ceramics in which, for example, ogakuzu and fir-gara are added and mixed, and the mixture is dried in a block state or in another suitable shape, and then fired to burn out the bubble-forming material to become porous. .. (4th paragraph)

Patent Document 2 discloses a method for treating waste liquid / waste water containing an organic chlorine compound using porous ceramics. As the above-mentioned method for producing porous ceramics, clay collected from the Seto region, a pore-forming material such as sawdust, and water are mixed, molded into an appropriate shape, dried, and the temperature of the dried molded body is adjusted to the pores in the molded body. By self-combustion of the forming material, the temperature is raised from room temperature to 600 to 800 ° C. over 5 to 15 hours, held at 600 to 800 ° C. for 3 to 7 hours, then raised to 1200 to 1500 ° C., and at 1200 to 1500 ° C. It is disclosed that the crusher treatment is performed after firing for 4 to 8 hours.

Patent Document 3 proposes a powdery ceramic having micropores that absorb, charge, and discharge static electricity. This powdery ceramic is used by mixing it with paint to prevent shellfish such as barnacles and crows and marine organisms such as seaweed from adhering to the bottom of the ship.

In addition, wood knots are known as a type of clay mineral. This knot is a granite weathered kaolinite (Al ₂ Sl ₂ O ₅ (OH) ₄ ) buried and deposited together with swamp plants and driftwood, and is particularly rich in organic matter. Patent Documents 4 to 6 can be mentioned as prior arts relating to this wood section.

In Patent Document 4, wood nodes are used as functional ceramics that promote the growth of living organisms and change water, food, etc. into safe and harmless ones.

Patent Document 5 pays attention to the fact that carbides such as magnetic cards and magnetic films exhibit remarkable water purification ability, and proposes to solidify them with a binder to obtain a desired shape. As an example of this binder, bentonite, magnesite, light-baked magnesium, magnesium hydroxide and brown sugar solution as well as wood-knot clay are mentioned.
In other words, Kibushi clay is listed as a binder and is not used to decompose harmful substances.

In Patent Document 6, active soil for ion exchange and negative ions are generated as a purifying material for purifying organic wastewater containing oil turbidity (solid oil + liquid oil) accumulated in a grease trap of a restaurant or the like. It has been proposed that the clay contains a component (for example, ceramic), and the wood-knot clay is listed as one of the other additives instead of the above-mentioned main component. (Paragraph 0012)

Non-Patent Documents 1 and 2 are mentioned as seawater purification systems containing oil (organic matter).
Non-Patent Document 1 discloses a seawater purification system in which UF (ultrafine membrane), CAF (ceramic adsorption filter) and RO (reverse osmosis membrane) are arranged in order from the upstream side.

Further, Non-Patent Document 2 has a structure in which water molecules smaller than oil permeate the flat membrane and are recovered as filtered water by applying pressure to seawater containing oil (organic matter) on the outside of the ceramic flat membrane. It is disclosed.

JP-A-59-087091 Japanese Unexamined Patent Publication No. 10-18643 Japanese Unexamined Patent Publication No. 2012-131961 Japanese Unexamined Patent Publication No. 11-079864 Japanese Unexamined Patent Publication No. 2000-246277 Japanese Unexamined Patent Publication No. 2006-026516

Development of Ceramic Adsorption Filter for Seawater Desalination Pretreatment Hitachi Metals, Ltd. 2019 News Release Ceramic flat film system Meidensha products and services

Porous ceramics are used as a water purifier, but when used as a water purifier containing a large amount of oil such as produce water, if the pore size is smaller than the oil molecules, the oil cannot be removed. Even if the pore size is suitable for removing oil molecules, it causes clogging and cannot be used for continuous purification.

Even if a viscous mineral such as zeolite is fired, the mesh is too fine, and after mixing with a pore-forming material such as sawdust, it is fired to gasify and remove sawdust, forming continuous pores large enough to allow water to enter. However, oil molecules cause clogging.

In the system disclosed in Non-Patent Document 1, UF and CAF must be regenerated frequently, and in Non-Patent Document 2, the flat membrane surface needs to be frequently washed by water discharge, which is troublesome to maintain.

Kibushi clay has a secondary viscosity containing a large amount of impurities such as organic substances (carbides), and when the carbides are vitrified by firing, quartz, alumina, and metals are fused and activated on the vitrified surface. The present invention has been made by paying attention to the fact that oil is decomposed by the catalytic action of this activated surface.

The first invention is a method for producing a purifying material by reduction firing, and specifically comprises the following steps 1 to 6.
First step: Kibushi clay and plant-derived organic matter are kneaded and molded by adding water.
Second step: The kneaded molded product is set in a furnace and heated at 300 ° C. or lower to remove water in the molded product.
Third step: The molded product from which water has been removed is held at 400 to 500 ° C. and completely carbonized.
Fourth step: The firing temperature is raised to 750 to 850 ° C., and the temperature is maintained at this temperature to gasify the bases and nitrates in the knot clay to form continuous pores.
Fifth step: The temperature is raised to 1050 ° C., the environment inside the furnace is reduced, and the continuous pore surface is vitrified.
Sixth step: The temperature is raised to 1.25 to 1300 ° C. in the reduced state, and by maintaining this temperature, quartz, alumina and metal are welded to the vitrified portion to activate the pore surface.

The second invention is a method for producing a purifying material by oxidative firing, and specifically comprises the following steps 1 to 6.
First step: Kibushi clay and plant-derived organic matter are kneaded and molded by adding water.
Second step: The kneaded molded product is set in a furnace and heated at 300 ° C. or lower to remove water in the molded product.
Third step: The molded product from which water has been removed is held at 400 to 500 ° C. and completely carbonized.
Fourth step: The firing temperature is raised to 750 to 850 ° C., and the temperature is maintained at this temperature to gasify the bases and nitrates in the knot clay to form continuous pores.
Fifth step: The continuous pore surface is vitrified by raising the temperature to 950 ° C. while maintaining the oxidized state in the furnace.
Sixth step: The temperature is raised to 1200 to 1300 ° C. in the oxidized state, and by maintaining this temperature, quartz, alumina and metal are welded to the vitrified portion to activate the pore surface.

According to the method for producing a purifying material (CAPS: Continuous & Amorphous Porous Surfaces) according to the present invention, the surface of continuous pores of the purifying material is vitrified, and quartz, alumina and metal are fused to the vitrified surface. When the oil contained in the water comes into contact with the oil, it is decomposed and removed.
The CAPS has continuous pores that allow oil molecules to enter, and a part of the metal (heavy metal) contained in the wood nodes is exposed on the surface of the pores. This metal acts as a catalyst and decomposes oil.

Since the purifying material produced by the method of the present invention does not adsorb oil on the surface of the pores, it can be used maintenance-free for a long period of time without causing clogging.

Graph showing an example of temperature control when manufacturing a purifying material by reduction firing Graph showing an example of temperature control when manufacturing a purifying material by oxidative firing Photograph of the purifying material manufactured by the method of the present invention Enlarged photograph of the purifying material produced by the method of the present invention Enlarged photograph of a comparative example using only Kibushi clay as a material

First, Kibushi clay and plant-derived organic matter are kneaded with water and molded to be used as a starting material. The mixing ratio (% by weight) of the wood-knot clay, the organic matter derived from the plant, and water is preferably 80 to 50:20 to 50. Compared to zeolite, wood-knot clay contains a large amount of organic substances and metals, and the surface after firing is easily activated.
Examples of plant-derived organic matter include sawdust and wood edges. Further, as a preferable size, the diameter of the continuous pores formed after firing is set to a size that allows oil molecules to penetrate.
In addition to the above materials, nepheline (nepheline) may be added.

The above materials are kneaded and molded into a predetermined shape by pressure molding or pouring (slurry molding). Then, as shown in FIG. 1, the water content in the molded product is removed at a temperature of 300 ° C. or lower.

After that, when the temperature is raised, firing starts between 400 and 500 ° C., self-combustion ends, and complete carbonization occurs. Then, if the temperature rise is continued as it is, activation and expansion of molding start at around 570 ° C.

After that, the temperature is raised from about 600 ° C. to about 800 ° C. at a heating rate of 50 ° C./h, and the temperature is maintained at this temperature for 3 to 5 hours. At this temperature, bases, nitrates, etc. in the wood section clay are gasified, and activation of plant-derived organic matter is also started.
Since the above gas is released to the outside, continuous pores are formed as shown in FIGS. 3 and 4. In addition, relatively large holes that allow water containing oil to easily enter are also formed, which greatly increases the total surface area.

The temperature is raised from 800 ° C. at a heating rate of 100 ° C./h, and in the case of reduction firing from around 950 ° C., the amount of air and gas is reduced to create a reducing atmosphere in the furnace.
If the temperature is continuously raised as it is, the ash content of the wood-knot clay and plants (organic matter such as sawdust) gradually vitrifies at around 1050 ° C.

Here, in the above ash content, along with calcium (Ca), magnesium (Mg), potassium (K), phosphorus (P), etc., lead (Pb), cadmium (Cd), mercury (Hg), etc. It contains a small amount of heavy metals.

In addition, vitrification is a phenomenon in which ash melts and becomes non-fluid without taking a crystal structure. It looks the same as a solid, but is non-consolidated (amorphous) with an irregular molecular structure like a liquid. ).

The vitrified layer is formed on the surface of continuous pores formed by the release of gas, and quartz, clay component, alumina, and metal (heavy metal) are fused to this glass layer. By fusing these components, the surface of the continuous pores is activated (activated), and oils and pollutants in contact with the surface of the continuous pores are decomposed.
Table 1 below shows the physical property values of the purifying material manufactured by the above manufacturing method.

FIG. 2 shows an example of producing a purifying material by oxidative firing. The difference from reduction calcination is that the temperature is gradually raised from around 950 ° C in the oxidized state, and the maximum temperature reached is 1250 ° C, which is slightly lower than that of reduction calcination. It is a point that was made.

FIG. 3 is a photograph of the purifying material produced by the method of the present invention, FIG. 4 is an enlarged photograph of the purifying material, and FIG. An enlarged photograph of the example is shown. From these photographs, with only Kibushi clay, which does not knead organic matter such as sawdust, the texture becomes finer and the contact area with water becomes smaller like ceramics after firing, but by kneading organic matter such as sawdust, open cells Is formed, the contact area with water becomes large, and oil molecules in the water are trapped.

Table 2 below shows the rate of decrease in oil content (residual oil content from 100 ppm) when the produced water is purified using the purifying material produced by the method of the present invention. It can be seen that various oils have been significantly removed (decomposed).

Table 3 shows the removal rate of pollutants other than oil. From this table, the purifying materials produced by the method of the present invention include not only oil but also bicarbonate (Bicarbonate), chloride (Chloride), sulfate (Sulfate), sodium (Sodium), calcium (Calcium), magnesium ( Magnesium), potassium (Potassium), barium (Barium) and strontuim (Strontuim) were found to be significantly removed.

The purifying material produced by the production method according to the present invention can be used not only for producing water but also for purifying tanker ballast water, wastewater of food processing factories and chemical factories, car wash wastewater, sewage and the like. Furthermore, it was confirmed that the purifying material produced by the method of the present invention has the effect of lowering the values of COD and BOD.

Claims (2)

A method for manufacturing a water purification material consisting of the following steps.
First step: Kibushi clay and plant-derived organic matter are kneaded and molded by adding water.
Second step: The kneaded molded product is set in a furnace and heated at 300 ° C. or lower to remove water in the molded product.
Third step: The molded product from which water has been removed is held at 400 to 500 ° C. and completely carbonized.
Fourth step: The firing temperature is raised to 750 to 850 ° C., and the temperature is maintained at this temperature to gasify the bases and nitrates in the knot clay to form continuous pores.
Fifth step: The temperature is raised to 1050 ° C., the environment inside the furnace is reduced, and the continuous pore surface is vitrified.
Sixth step: The temperature is raised to 1.25 to 1300 ° C. in the reduced state, and by maintaining this temperature, quartz, alumina and metal are welded to the vitrified portion to activate the pore surface. A method for manufacturing a water purification material consisting of the following steps.
First step: Kibushi clay and plant-derived organic matter are kneaded and molded by adding water.
Second step: The kneaded molded product is set in a furnace and heated at 300 ° C. or lower to remove water in the molded product.
Third step: The molded product from which water has been removed is held at 400 to 500 ° C. and completely carbonized.
Fourth step: The firing temperature is raised to 750 to 850 ° C., and the temperature is maintained at this temperature to gasify the bases and nitrates in the knot clay to form continuous pores.
Fifth step: The continuous pore surface is vitrified by raising the temperature to 950 ° C. while maintaining the oxidized state in the furnace.
Sixth step: The temperature is raised to 1200 to 1300 ° C. in an oxidized state, and by maintaining this temperature, quartz, alumina, and a metal are welded to the vitrified portion to activate the pore surface.

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