JPH06345676A - Crystallizer for producing phenolic compound or the like - Google Patents

Abstract

PURPOSE:To provide the subject crystallizer capable of preventing worn powder from contamination into and foreign substances from dissolution into a liquor to be treated, thus enabling high-quality phenolic compound or bisphenol compound to be produced smoothly and assuredly. CONSTITUTION:Ultrahigh molecular weight polyethylene is used for the scraping edge 23 of a scraper 20 to come into contact with the heat transfer surface of a crystallizer body; thereby, worn powder from the scraping edge 23 is prevented from contaminating into a liquor to be treated and the components of the scraping edge 23 from dissolving into the liquor.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a crystallizer used for producing phenols and bisphenols.

[0002]

2. Description of the Related Art Conventionally, as an indirect cooling type crystallizer, as shown in FIG. 3, a jacket 2 is provided on the outer periphery of a cylindrical crystallizer main body 1, and a refrigerant is provided on the lower and upper parts of the jacket 2. An inlet 3 and a refrigerant outlet 4 are respectively provided, and a drive shaft 5 is rotatably provided at the inner center of the crystallizer main body 1, and an inner impeller 6, a draft tube 7, an outer impeller 8 and It is known that the scraper 9 is integrally attached, while the drive machine 10 for rotating the drive shaft 5 is connected to the upper end surface of the crystallizer main body 1. In the crystallizer configured as described above, the object to be treated is housed inside the crystallizer main body 1, and the refrigerant is introduced from the refrigerant inlet 3 into the jacket 2
The inside of the crystallizer main body 1 is indirectly cooled by being supplied into the inside of the crystallizer outlet 4, and the drive shaft 5 is rotated by the driving machine 10, and the inside of the crystallizer main body 1 is rotated by the internal impeller 6, the draft tube 7 and the external impeller 8. By circulating the object to be treated, the object to be treated inside the crystallizer main body 1 is mixed uniformly, while the crystals attached to the inner peripheral surface (cooling surface) of the crystallizer main body 1 are scraped by the scraper 9 By scraping off with a scraper, it is possible to prevent a decrease in the cooling capacity due to the adhesion of crystals to the cooling surface.

[0003]

By the way, as the material of the scraper 9 of the indirect cooling type crystallizer, metal or resin is used. Of these, the metal scraper 9
In the case of, the scraper 9 cannot be brought into contact with the cooling surface of the crystallizer main body 1, and therefore, since there is a slight gap between the cooling surface and the scraper 9, the crystals attached to the cooling surface can be removed. There is a problem that it cannot be completely removed, and the adhered crystal that cannot be removed becomes a heat transfer resistance and a large heat transfer coefficient cannot be obtained. On the other hand, the resin scraper 9 can obtain a high heat transfer coefficient because it can be operated by bringing it into contact with the cooling surface. Must be satisfied.
In particular, in the case of a substance that requires high quality such as bisphenol, it is necessary to avoid adversely affecting the product quality due to abrasion powder and components eluted from the resin. In this regard, MC nylon, which has been widely used as a material for the scraper in the related art, has excellent wear resistance, but cannot be used for phenols and bisphenols because MC nylon itself dissolves. Therefore, a phenol resin is used as a material having resistance to phenols and bisphenols and excellent in abrasion resistance. However, this phenolic resin has a problem that a small amount of colored abrasion powder is generated and mixed into the final product as a foreign substance. Further, there is a problem that some leaching components are present from the phenol resin, which causes the liquid to be treated to be colored and the final product to be colored.

The present invention has been made in view of the above circumstances, and an object thereof is to contact a heat transfer surface or a scale adhering surface of a crystallizer main body during the production of phenols and bisphenols. By using ultra-high molecular weight polyethylene for sliding parts such as scrapers and rotating shafts of stirrers, it is possible to prevent abrasion powder from mixing into the liquid to be treated and elution of foreign substances, and to ensure high-quality phenols and bisphenols. It is intended to provide a crystallizer for producing phenols and the like, which can smoothly and reliably produce the same.

[0005]

In order to achieve the above-mentioned object, the present invention provides a crystallizer for producing phenols or the like for crystallization by cooling phenols or bisphenols,
Ultra high molecular weight polyethylene is used for the sliding parts that move relative to each other while contacting each other. Further, in order to improve abrasion resistance, it is possible to blend glass fiber, liquid crystal polymer, or the like with ultra-high molecular weight polyethylene. Further, the higher the molecular weight of ultra-high molecular weight polyethylene, the higher the abrasion resistance, but a general molecular weight is also sufficient.

[0006]

In the crystallizer for producing phenols and the like of the present invention, the sliding portion such as the scraper or the rotating shaft of the stirrer that comes into contact with the heat transfer surface of the crystallizer body or the scale adhering surface has an ultra-high height. By using the molecular weight polyethylene, the abrasion powder is prevented from being mixed into the object to be treated from the sliding portion, and the components of the sliding portion are prevented from being eluted into the object to be treated.

[0007]

Embodiments of the present invention will be described below with reference to FIGS. The present invention is not limited to the following examples unless it exceeds the gist.

FIGS. 1 and 2 show a scraper 20 to which the present invention is applied, and this scraper 20 is used in place of the scraper 9 of the crystallizer shown in FIG.
In the scraper 20, the scraper main body 22 is attached to the connecting member 21 connecting the draft tube 7 and the scraper main body 22.
And the scraper body 2
A spring 24 for pressing the scraping piece 23 against the inner peripheral surface (cooling surface) of the crystallizer main body 1 is provided inside the apparatus 2. The scraping piece 23 is made of ultra-high molecular weight polyethylene.

Next, a case in which the present invention is carried out more specifically will be described. [Example 1] A cylindrical stainless steel container having an inner diameter of 310.5 mm and a height of 450 mm was provided with a stirring shaft, resin pieces were provided in the radial direction (4 directions) from the stirring shaft, and pressed against the inner wall surface of the container by a spring. Keep it. Then, while the liquid is put in this container, the stirring shaft is rotated while pressing the resin piece against the inner wall surface so that the resin piece continuously rubs against the inner wall surface. The operation was performed under the following conditions using ultra-high molecular weight polyethylene for the four resin pieces of the above apparatus. Liquid used Phenol water Rotation speed 130 rpm Temperature Room temperature Operation time 231 hours Weight change of resin piece before and after this operation is an average of 4 pieces-
It was 0.05%, which was a slight decrease.

[Example 2] In a cooling crystallization operation of bisphenols using an indirect cooling type scraping crystallizer having an inner diameter of 2.5 m and a height of 6 m, ultrahigh molecular weight polyethylene was used for a scraping blade. It was used continuously for one year. As a result, the average wear rate of the scraping blade was about 5%, but there was no deterioration in cooling crystallization performance during operation for one year, and there was no effect on the quality of the final product. I was able to produce.

"Comparative Example 1" An apparatus similar to that of Example 1 above,
When a phenolic resin was used for the resin piece under the conditions, the weight change before and after the operation was about -0.4% on the average of four pieces,
The weight change was greater than that of ultra high molecular weight polyethylene.
Further, the color of the liquid after the operation turned a little yellow, and it is considered that there was some elution from the resin. Furthermore, blackish abrasion powder was floating in the liquid.

"Comparative Example 2" In a cooling crystallization operation of phenols using an indirect cooling type scraping crystallizer having an inner diameter of 0.8 m and a height of 2 m, a scraping blade is made of Teflon resin. As a result, in one week, the scraping blade was completely worn out and the scraping operation could not be performed, and the crystals adhered to the cooling surface to deteriorate the heat transfer performance, and the operation became impossible.

[0013]

As described above, according to the present invention, when the phenols and the bisphenols are produced, the scraper and the rotating shaft of the stirrer that come into contact with the heat transfer surface and the scale adhering surface of the crystallizer main body can be used. By using ultra high molecular weight polyethylene for the sliding part, it is possible to prevent abrasion powder from mixing into the object to be processed from the sliding part, and to elute the components of the sliding part into the object to be processed. And high quality phenols and bisphenols can be produced smoothly and reliably.

[Brief description of drawings]

FIG. 1 is a side view of a scraper portion showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a perspective view showing an indirect cooling type scraping crystallizer.

[Explanation of symbols]

 20 scraper 23 scraping piece (sliding part)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Reference number in the agency FI Technical display location // C10N 40:02 50:08 (72) Inventor Masahiro Kodama 1 Iezaki Kaigan, Ichihara, Chiba 1 Within Idemitsu Petrochemical Co., Ltd. (72) Inventor Hideki Noboshi 1 Iezaki Kaigan, Ichihara-shi, Chiba 1 Idemitsu Petrochemical Co., Ltd.

Claims (1)

[Claims] 1. A crystallizer for producing phenols or the like, which crystallizes by cooling phenols or bisphenols,
A crystallizer for producing phenols and the like, characterized in that ultra-high molecular weight polyethylene is used for the sliding parts that move relative to each other while contacting each other.