JPH038440A - Adsorbent for oil mist - Google Patents

Abstract

PURPOSE:To effectively adsorb oil mist by using carbonaceous spheres obtd. by forming glassy carbon in the surface layer parts of carbon black pellets. CONSTITUTION:Thermosetting phenol or furan resin is dissolved in a volatile org. solvent such as alcohol or ether, the resulting resin soln. is impregnated into pellets of carbon black such as oil furnace black or gas furnace black and the pellets are heated. Part of the impregnated resin soln. penetrates into the pellets but most of the soln. is fixed in an adhered state. Carbonization is then carried out by firing in a nonoxidizing atmosphere to convert the resin layer parts into glassy carbon. Carbonaceous spheres having >=0.4ml/g total pore volume and >=20nm average pore diameter are obtd. and oil mist can be effectively adsorbed on the carbonaceous spheres.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an oil mist adsorbent used for adsorption and removal of various oil mist (oil vapor).

[Conventional technology]

Felt-like adsorbents made of braided fibers of stainless steel, alumina, glass, etc. are commercially available as adsorbents for oil mist. However, these materials are expensive and have problems in handling, such as becoming short fibers and scattering during construction.

In this respect, granular activated carbon such as coal-based or coconut shell-based activated carbon, which has been widely used as an adsorbent for gas/liquid phases, is advantageous in terms of both price and handling. However, although activated carbon exhibits excellent removal performance for vapor phase adsorption of gases, vapors, etc., it has the disadvantage that it does not exhibit sufficient adsorption effects for minute liquid phase particles such as oil mist.

[Problem to be solved by the invention]

The reason why activated carbon does not exhibit sufficient adsorption performance for oil mist is that its pore structure mainly has a nitrogen adsorption specific surface area (N
! SA) It is composed of high micropores represented by a specific surface area of 1000 rrr/g or more, and the micropore volume (micropores of nm or more) required for oil mist adsorption is small.

In the present invention, carbon spherical bodies with a glassy carbon film formed on the surface layer of carbon black, which has a different structure from activated carbon, preserve a large volume of micropores and have other properties that are effective in adsorbing oil mist. This was developed based on this knowledge.

Therefore, an object of the present invention is to provide a carbonaceous adsorbent that can effectively adsorb oil mist.

(Means for Solving the Problems) To achieve the above object, an oil mist adsorbent is a carbonaceous spherical body formed by adhering glassy carbon to the surface layer of a carbon black pellet. In the pore distribution measurement using a mercury porosimeter, the structural feature is that the total pore volume is 0.4 tying or more and the average pore diameter calculated from the pore distribution diagram is 20 nl11 or more. do.

The carbonaceous spherical bodies of the present invention are manufactured as follows.

First, a thermosetting resin is dissolved in an appropriate organic solvent and impregnated into carbon black pellets, followed by heat treatment.

Carbon black includes oil furnace black, gas furnace black, channel black, thermal black, acetylene black, lamp black,
Various production systems such as by-product black can be used, and the product is formed into spherical pellets by conventional granulation means and used.

Phenol-based or furan-based thermosetting resins that are easily converted into glassy carbon by carbonization are useful, and they can be dissolved in volatile organic solvents such as alcohol, ether, acetone, benzene, toluene, and xylene. used.

The impregnation treatment can be carried out, for example, by filling a column with carbon blank pellets and letting the resin solution flow down, by spraying the resin solution while transferring the carbon black pellets in a rotating cylindrical tube, or by immersing the carbon blank pellets in the resin solution. This is done using methods such as

A portion of the resin solution impregnated into the carbon black pellets by these methods penetrates into the inside of the pellets, but as the solvent continues to fail during heating, it migrates to the surface layer and is fixed in an adhered state.

Next, this was heated at 1500 to 2000° in a non-oxidizing atmosphere.
When carbonized by firing in a temperature range of approximately C, the resin layer portion is converted to glassy carbon, and a carbonaceous spherical body in which glassy carbon is adhered to the surface layer of carbon black pellets is obtained.

The adsorbent of the present invention is not only the above-mentioned carbon sphere, but also has a total pore volume of 0.4 tall/g or more in pore distribution measurement using a mercury porosimeter, and an average pore diameter calculated from a pore distribution diagram. is required to have a characteristic of 20 nm or more, and if this requirement is not satisfied, sufficient adsorption performance for oil mist cannot be imparted.

These pore structure characteristics can be imparted by controlling the manufacturing conditions of the carbonaceous spheres described above, but they are largely influenced by the pore characteristics of the carbon black used as the raw material.

[For production]

The adsorbent for oil mist according to the present invention is a carbonaceous material with high purity with a carbon content of over 99% and sphericity with an angle of repose of about 30°, and has a total pore volume suitable for oil mist adsorption. 0.4 af/g or more and average pore diameter 2
It has a pore structure characteristic of 0 nn or more.

When adsorbing oil mist, firstly, high purity properties contribute to improving wettability with oil mist, and sphericity facilitates workability when filling and discharging columns etc. It acts to improve contact with the These actions reduce the total pore volume to 0.4 m7
Together with the adsorption performance based on g or more and an average pore diameter of 20 nm or more, it functions to further enhance the adsorption effect.

〔Example〕

The present invention will be explained below with reference to Examples.

(1) Production of adsorbent Two types of carbon blanks [Example 1: Tokai Carbon ■
"5EAS↑116" manufactured by Tokai Carbon Corporation, Example 2: "5EAST 9" manufactured by Tokai Carbon ■] were sieved to collect particles in the particle size range of 0.5 to 2.0 diameter. This carbon black pellet was placed in a rotating cylindrical tube, and 2
．． While spraying a 5% acetone solution, it was rotated at a speed of 1 Qrpm to uniformly impregnate it.

Next, heat the solvent while transferring it to volatilize the solvent component,
The resin layer was cured.

After the hardening treatment, the granules are heated at 1500°C in a nitrogen gas atmosphere furnace.
The resin component was fired and carbonized by holding the resin at a temperature of 30 minutes.

The carbonaceous adsorbent created in this way exhibits properties that are extremely close to a perfect sphere, with carbune black sealed inside and a strong and smooth glassy carbon coating on the outer layer, and its elemental analysis value is C: 99%, H: 0.05% or less, N:
It was confirmed that it was a highly pure modified carbonaceous material with a content of Q: 1% and O:O:X%.

(2) Evaluation of oil mist adsorption performance An acrylic resin cylindrical column with an inner diameter of 60 m and an outer diameter of 70 cm was filled with adsorbent, and both ends were fixed with stainless steel nets. The adsorbent filling conditions at this time were: filling 150g, bulk density 0.
The particle size was set at 31 g/cc and a particle size of 2000 to 250 ttts. The above-mentioned adsorbent-filled column was connected to the exhaust pipe of a commercially available vacuum pump and driven, and changes in adsorption amount over time were measured. The amount of oil mist generated was controlled by adjusting the amount of gas on the suction side.

(3) Adsorption Results The measurement results of the adsorption performance evaluated as described above are shown in Table 1 in comparison with the characteristics of the adsorbent.

For comparison, the results of evaluating commercially available coal-based spherical activated carbon are also shown (comparative example).

The Examples of the present invention maintained stable oil mist adsorption performance over a long period of time compared to the Comparative Examples, and it was observed that Example 1, which had a large pore volume and average pore diameter, exhibited particularly high performance. Ta.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide an oil mist adsorbent having excellent adsorption performance using a carbonaceous material that is inexpensive and easy to handle, so it is of great industrial benefit.

Claims (1)

[Claims] 1. A carbonaceous spherical body formed by adhering glassy carbon to the surface layer of carbon black pellets, which has a total pore volume of 0.4 in pore distribution measurement using a mercury porosimeter.
An adsorbent for oil mist having characteristics of ml/g or more and an average pore diameter calculated from a pore distribution diagram of 20 nm or more.