JPS6042465A - Production of acetylene black - Google Patents

Abstract

PURPOSE:To produce acetylene black having good hydrochloric acid absorption consistently over a long period of time, by using a thermal cracker having a thermal cracking part and an aging part in series and treating acetylene gas under specified conditions. CONSTITUTION:A vertical tubular cracker composed of a thermal cracking part 1 and an aging part 2 and satisfying the relationship of D1/D2=1.2-2.2 and L1/L2=0.4-1, wherein D1 is the diameter of the thermal cracking part 1 and L1 is the length thereof, and D2 is the diameter of the aging part 2 and L2 is the length thereof, is used. Acetylene gas [which may contain not more than 40wt% (in terms of carbon) unsaturated hydrocarbons such as propylene and benzene] is thermally cracked at 1,900 deg.C and cracked products contg. carbon aerosol are allowed to stay for 30-150sec. in the thermal cracking part 1. The formed aerosol is allowed to stay at 1,700 deg.C or above for 20-90sec to produce acetylene black in the aging part 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an acetylene blank, and more specifically, to a method for producing an acetylene blank that can be operated for a long period of time without reducing the hydrochloric acid absorption of 14 products.

Conventional methods for producing acetylene blanks include thermally decomposing acetylene gas, decomposing the continuously supplied acetylene gas using the decomposition heat generated at that time, and continuously producing acetylene black while maintaining the required temperature. ta
There is a known method for making it (Handbook Car Gun Blank September 1950 edition). However, when acetylene black is produced using this known method, the produced acetylene black adheres to the inner wall surface of the furnace, resulting in a decrease in the amount of hydrochloric acid absorbed by the product and clogging of the decomposition furnace, resulting in poor quality. The drawback was that it was not possible to produce good acetylene black over a long period of time.

The present invention is characterized in that acetylene gas A or unsaturated hydrocarbon B is added to acetylene gas A per 100 parts by weight of carbon in said A.
The raw material added so that the carbon content is 40 parts by weight or less is processed into a thermal decomposition section 1 and a ripening section 2.
The ratio of the diameter D1 of the pyrolysis section 1 to the diameter D2 of CDI/
D2) is 1.2 to 2.2, and the length of the thermal decomposition section 1 is relative to the length of the aging section 2.

When supplying to a vertical cylindrical cracking furnace with a ratio LLI/L2) of 6.4 to 1.0 and thermally decomposing it to produce an acetylene blank, the heat Wr part 1 and the aging part 2 were This is a method for producing an acetylene blank characterized by operating under certain conditions.

Thermal decomposition section 1: The carbon aerosol in the decomposition product is placed in the atmosphere of the decomposition product at a temperature of 1900°C or higher for 30 to 150 seconds n1? Let it accumulate.

Aging section 2: The carbon aerosol introduced from the thermal decomposition section and having a temperature of 1,700°C or higher is allowed to accumulate for 20 to 90 hours in terms of standard conditions.

The contents of the present invention will be explained in detail below.

As the raw material used in the present invention, acetylene gas A or acetylene gas A to which one or more selected from ethylene, monomial, polycyclic, and aromatic unsaturated hydrocarbons can be used. It is not necessarily limited to these.

Specific examples of ethylenically unsaturated hydrocarbons include ethylene, propylene, buknoene, etc., and specific examples of polycyclic unsaturated hydrocarbons include benzene, freon-1 oil, naphthalene, and the like.

The selection of the unsaturated hydrocarbon B described above is determined by the structure of the pyrolysis furnace, the decomposition heat of the raw material, the operating method, etc., but the addition ratio to the acetylene gas is determined by the carbon content in the acetylene gas A being 100 It is preferable that the carbon content in the unsaturated hydrocarbon B is 40 parts by weight or less relative to parts by weight.

If the proportion of unsaturated hydrocarbon B exceeds 40 parts by weight, it is not possible to maintain the temperature for continuous thermal decomposition of the raw material, so the amount of hydrochloric acid absorbed by the product acetylene black decreases, which is undesirable. . Next, unsaturated hydrocarbon B
When mixing with '5 acetylene gas, it is sufficient to vaporize the hydrocarbon B in a vaporizer and then carry out 7 steps.

The raw materials explained above are fed to a vertical cylindrical furnace as shown in FIG. This furnace consists of a pyrolysis section 1 and a ripening section 2,
Moreover, the diameter D of the thermal decomposition section 1 is relative to the diameter D2 of the aging section 2.
The ratio of I (D, /D2) is 1.2 to 2.2, preferably 1
．． 3 to 1.8, and the ratio (L + / L 2) of the length of the thermal decomposition section 1 to the length L2 of the aging section 2 is 0.
It is preferable to have a shape of 4 to 1.0, preferably 06 to 0.8. In other words, the pyrolysis furnace used in the conventional method does not have a pyrolysis section and a ripening section;
The thermal decomposition section and the ripening section are complicated and intertwined depending on the operating conditions, making it difficult to maintain quality and mass production.However, in the present invention, the thermal decomposition section and the ripening section are clearly separated and exist independently. By using such a furnace, stable quality and mass production are possible.

In other words, in the case of the pyrolysis furnace used in the present invention, in the pyrolysis section 1, while maintaining the necessary temperature to make the pyrolysis reaction uniform, the heat component 1yf reaction is completed by staying in the atmosphere for a predetermined time. It is assumed that a chain structure has developed (hereinafter referred to as a carbon aerosol).

Next, in the aging section 2, the heat generated by the thermal decomposition reaction adjusts the molecular arrangement and allows the product to remain for a time necessary to strengthen the chain structure, without reducing the amount of hydrochloric acid absorbed by the product. Blockage of the furnace is prevented and long-term operating power is possible.

Regarding the furnace used in the present invention, if the shape is outside the above range, it will be difficult to achieve the purpose of the present invention.

The raw material supplied to the decomposition furnace described above is first thermally decomposed at a temperature of 1900° C. or higher in the thermal decomposition section 1 to generate a decomposition product containing carbon aerosol.

What is required here is to allow the decomposition products containing the aerosol to remain in the thermal decomposition section 1 for a predetermined period of time, and the conditions for this are a temperature of 1900°C or higher and a time period of 30 to 150 seconds in terms of standard conditions. It is to let it accumulate. If the temperature of the thermal decomposition section 1 where the material is stored is lower than 1900° C., the thermal decomposition reaction of the raw material will not be completed and a chain structure will not develop.

1. If the residence time is less than 30 seconds, the chain structure of the product will not develop, and if it exceeds 150 seconds, the secondary particles of the acetylene black produced will aggregate.

The residence time is adjusted by changing the feed rate of the raw material. The raw material gas linear velocity is 0.01 to 0.0 in terms of standard conditions.
0.6 m/sec, preferably 0.02 to 0.05 m/sec is suitable.

Next, the carbon aerosol-containing pyrolysis product produced in the pyrolysis section 1 is introduced into the aging section 2.

In the aging section 2, the car? The aerosol is modified, and the conditions are preferably that it is kept at a temperature of 1700° C. or higher and for 20 to 90 seconds.

If the temperature is less than 1700° C., the molecular arrangement of carbon ytf aerosol in the decomposition product cannot be adjusted, so the amount of hydrochloric acid absorbed by the product decreases, which is not preferable.

Furthermore, if the residence time is less than 20 seconds, the molecular arrangement of the carbon aerosol cannot be adjusted and reformed, and if the residence time exceeds 90 seconds, the agglomeration of the secondary particles of the carbon aerosol will be promoted and the particles will accumulate on the furnace wall. This is not preferable as it increases the number of

In this case, the gas linear velocity is 0.03 to (1
, 14m7 seconds, preferably 0.05-Q, , L l
To prevent the acetylene blank from adhering to the furnace wall without impairing the ripening of the acetylene blank produced in the p-pyrolysis section by increasing the gas flow rate from that of m7 seconds and heat fraction j'l'1. Can be done.

As explained above, the method of the present invention enables effects and long-term operation by supplying the raw material gas to a pyrolysis furnace with a specific shape and reforming the carbon aerosol produced in the heat component 91 part 1 in the aging part 2. This product also achieves the productivity effects of 1.0 to 1.3 cc of hydrochloric acid compared to conventional products.
It is possible to produce 1.2 to 1.4 times more acetylene blank, which is 15g higher.

Next, the present invention will be explained by giving examples.

Example 1 and Comparative Example 1 Diameter D1 of heat component w1 part 1 of a pyrolysis furnace having the structure shown in FIG.
is 74 cm5, its length Ll is 250 m1, the diameter D2 of the ripening section 2 is 50 crn1, its length L2 is 360 crn + DI/D2 = 1.48, "l/
L2=0.69) with acetylene gas at 50 N”/
Acetylene blanks were completely produced by supplying them for a period of time.

For comparison purposes, 91 parts of the heat and the aging section were fed into a pyrolysis furnace with a diameter of 50 crn as shown in Fig. 2 with no distinction between the two, and acetylene gas was supplied at 40''/hour to produce 5r of acetylene gas.
ノ,lt=manufactured. These conditions and results are shown in Table 1.

Example 2 and Comparative Example 2 The same procedure was carried out except that the same raw material was supplied to the decomposition furnace used in Example 1, with the addition of acetylene gas of 58N 7''/hour and benzene heated to 0°C and vaporized for 21 hours. Example 1
I did the same thing.

The same procedure as in Example 2 was conducted except that the pyrolysis furnace used in Comparative Example 1 was used for comparison.

Comparative Example 3 The same procedure as in Example 1 was carried out except that acetylene gas was supplied to a thermal decomposition furnace having the structure shown in FIG. 2 at a rate of 2ON''/hour.

Comparative Example 4 The same procedure as in Example 1 was carried out except that acetylene gas was supplied to the decomposition furnace shown in FIG. 2 at a rate of 160 mm.

As shown in the Examples above, according to the method of the present invention, acetylene black with a high hydrochloric acid absorption capacity can be produced in large quantities by operating for a longer period than in the conventional case.

(Note 1) The residence time and gas linear velocity of the decomposition products listed in Table 1 were calculated according to the following method Vt.

(Note 2) The amount of hydrochloric acid absorbed was measured in accordance with JIS K1469. (Unit: 75 g l (Note 3) The operating time is expressed as the time from start to blockage in the furnace.

(Note 4) The temperatures in the pyrolysis section 1 and aging section 2 were determined by inserting a Glassy Carpin (manufactured by Tokai Cargan) protection tube to the center of the furnace, and measuring the temperature at the tip with an optical pyrometer.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a vertical cylindrical decomposition furnace used in an example of the present invention, and FIG. 2 is an explanatory diagram of a pyrolysis furnace used in a comparative example. What fraction 1...Pyrolysis section 2...Aging section Patent applicant Denki Kagaku Kogyo Co., Ltd.

Claims (1)

[Scope of Claims] Acetylene gas A or a raw material in which acetylene gas A contains unsaturated hydrocarbon B in an amount of 40 parts by weight or less of carbon in B based on 100 parts by weight of carbon in A is thermally decomposed. It consists of a section 1 and a ripening section 2, and the ratio (D + / D t) of the diameter D+ of the thermal decomposition section 1 to the diameter D2 of the ripening section 2 is 1.
．． 2 to 22, and the ratio LLs/Ltl of the length of the pyrolysis section 1 to the length of the aging section 2 is 0.4 to 1.0. Asena Reno Black T? ! ! A method for producing acetylene black, which comprises operating the thermal decomposition section 1 and the aging section 2 under the following conditions. Thermal decomposition part 1: The carbine aerosol in the decomposition product is allowed to remain in the atmosphere of the decomposition product at a temperature of 1900° C. or higher for 30 to 150 seconds in terms of standard conditions. Aging section 2: The carbine aerosol introduced from the thermal decomposition section and having a temperature of 1,700°C or higher is retained for 20 to 90 seconds in terms of standard conditions.