JPS5835237B2 - Seizouhouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a pitch for a binder suitable for producing coke for electrodes, coke for iron making, coke for foundries, and the like.

More specifically, the present invention relates to a method for obtaining lower olefins from straight-run petroleum heavy oil and producing pitch suitable for the above-mentioned uses that can replace coal tar pitch.

In the production of electrode coke, large amounts of pitch are used as a binder.

In addition, coke for iron and foundry manufacturing has traditionally been produced by carbonization of highly caking coal, but in recent years there has been a shortage of this type of coking coal. Proposed methods include adding pitch to charcoal as a binder and carbonizing it after pressure molding, or adding pitch to low-grade coal and carbonizing it.

Coal tar pitch is commonly used as a binder for these purposes.

However, since the supply of coal tar pitch is limited, various methods of producing petroleum pitch to replace it are being studied.

The present invention provides a method for producing a binder pitch that can replace coal tar pitch and is suitable for this purpose.

Conventionally, the general method for obtaining pitch from petroleum-based heavy oil is to heat-treat raw material heavy oil at 300 to 500'C and obtain pitch from the product.

Furthermore, in order to obtain high-quality pitch, the raw material heavy oil must first be thermally decomposed at a temperature of 900°C or higher and 0.1 seconds or less, and then the resulting liquid tar-like product must be pyrolyzed at 250 to 550°C for 1 minute or more. A two-step heat treatment method has been proposed (Kureha Chemical Co., Ltd., Special Publication No. 46-2417), and high-quality pitch is produced by decomposing raw material heavy oil with high-temperature steam of 1200-1800°C at a temperature of 900-1500°C. And 1/
It is said that it can also be obtained by a method of decomposition under conditions of 100 to 1/1000 seconds (Kureha Chemical - Okine Kako, Special Publication No. 16521/1989). It cannot be said that it is optimal for the purpose of efficiently obtaining lower olefins (e.g., ethylene, propylene natate), and methods using high-temperature steam have drawbacks such as requiring expensive equipment.

On the other hand, as a method for decomposing heavy oil in a relatively long reaction time, a method of switching between two regenerators has been put into practical use, and this method also produces pitch containing viscous bonding components. do.

However, this pitch contains a large amount of free carbon (quinoline solubles), up to about 40 fo.

Therefore, in order to obtain a pitch that can be used as a practical binder from this pitch, a complicated process such as removal of free carbon by centrifugation is required (Paccal, H.
Hydrocarbon Processing.

Jan 1974, p. 127).

In general, the thermal decomposition conditions of petroleum heavy oil suitable for the production of lower olefins, namely, temperature 700 to 900°C, reaction time (1
Under conditions of 1 to 10 seconds, a large amount of free carbon is produced as seen in the example of the regenerator reactor described above, and the pitch obtained therefrom is therefore unsuitable for use as a binder as is.

This time, for example, using a fluidized bed reactor using a carbonaceous material such as coke as a heat medium, we conducted a test using a straight-run petroleum heavy oil or similar When a substance is thermally decomposed, a large portion of the carbonaceous substance produced by this thermal decomposition is removed by adhering to the heating medium, and therefore, the quinoline solvent can be reduced to 15φ simply by separating the light oil from the liquid product. It has been found that a pitch suitable as a binder of some degree can be obtained.

Therefore, the present invention aims to produce petroleum straight-run heavy gas using a fluidized bed reactor using carbonaceous as a heat medium at a temperature of 700 to 900°C and a reaction time of 0.1 to 10 seconds, which is suitable for producing lower olefins. By thermally decomposing oil or similar substances to obtain a large amount of lower olefins, it can be used as a substitute for coal tar pitch by simply separating light oil from the resulting liquid without going through complicated processes such as centrifugation. To provide a method for obtaining a pitch suitable for a binder.

The straight-run petroleum heavy oil or similar substances used in the present invention include crude oil, its atmospheric or vacuum residue oil, asphalt, tar sand bitumen, and the like.

As the carbonaceous material which is the heating medium, separately manufactured coke, graphite, etc. or coke produced by this reaction can be used, and in particular, the sieve mesh 0.3 through which it passes can be used.
Particle sizes of ˜1.0 mm are preferred.

The process of the invention is usually carried out using two fluidized beds.

After the raw material heavy oil is preheated, it is supplied in the form of a mist to one fluidized bed (reaction tower) together with a diluent such as steam, and is decomposed by receiving heat from a carbon material as a heating medium.

The heat carrier particles from which heat has been removed by the reaction and to which carbonaceous substances produced by pyrolysis are attached are transferred to the other fluidized bed (regeneration tower), heated by external heat or self-combustion, and circulated to the reaction tower again. .

Reaction conditions are temperature 700-900℃, reaction time 0.1-1
0 seconds, the pressure is 0 to 10 kg/cvtG, and the weight ratio of diluent to feedstock heavy oil is in the range of 0.1 to 10.

The gaseous products of thermal decomposition are rapidly cooled and then separated into gaseous products (mainly lower olefins) and liquid products.

A light oil, such as a fraction with a normal pressure boiling point of 350° C. or less, is separated from this liquid to obtain the desired pinch.

The softening point of the pitch produced varies depending on the distillation temperature of the liquid product, but after separating the fraction with a boiling point of 35,000 or less at normal pressure, pitch having a softening point of about 100 to 150°C is obtained.

The pitch obtained by this method generally has a benzene-insoluble content of about 20 to 50 yen, a quinoline soluble content of about 10 to 20 yen,
Benzene soluble and quinoline soluble (β-component is about 10~
30%, and the residual carbon is approximately 50 to 70φ, which is comparable to coal tar pitch.

This pitch can be used alone or mixed with other pitches.
Alternatively, it can be cut banked with other tars or oils.

The invention is illustrated by the following examples.

Example 1 Petroleum vacuum residue oil was blown into a reactor in which petroleum coke with a diameter of 0.3 to LOmytt was flown, together with steam at a weight ratio of 1.7 times, the reaction temperature was 745°C, and the reaction time was 2.
0 seconds, reaction pressure 0.35 ky/ct? It was pyrolyzed with tG.

By separating the distillate with a normal pressure boiling point of 350°C or less by vacuum distillation from the oil obtained by cooling the product,
A pitch of 35.8φ was obtained for the feedstock oil.

The properties of this pitch are as follows.

Pitch having such properties is suitable as a binder.

Example 2 A reaction was carried out in the same manner as in Example 1 using cool sand bitumen as a raw material.

The reaction conditions were a temperature of 748°C, a reaction time of 1.7 seconds, and a reaction pressure of 0.15 ky/cr? LG, and the steam to feedstock weight ratio was 2.3.

By the same post-treatment as in Example 1, the raw material was reduced to 40.2
% pitch was obtained.

The properties of this pitch were as follows.

Softening point (ring and ball method) 107°C Benzene insolubles 23.7 Quinoline solubles 11.2% β-component 12.5 Residual carbon 57. Pitch having such properties is suitable as a binder.

Example 3 The performance of the pitch obtained in Example 1 and Example 2 as a binder was compared with that of coal tar pitch.

15 parts by weight of the above pitch or coal tar pitch was added to 85 parts of pulverized weakly caking coal, heated and mixed near the pitch calibration point, and then mixed at 300 kg/cy? The coal was molded at a pressure of 40 mm in diameter and 20 mrtt in height.

These briquettes were heated in an electric furnace to 900° C. at a temperature increase rate of 4.5° C./min, and maintained at the same temperature for 1 hour for carbonization.

The compressive strength of the obtained molded coke was as follows.

] -/L/ ll -ily e ”;/chi 1
Molded coke using the pitch of Example 1 using 17ky/ffl Molded coke 158kg/ant Example 2
Molding using a pitch of 127 kg/crt Therefore, the pitch according to the present invention can be favorably used as a binder.

Claims (1)

[Claims] 1 Using a fluidized bed reactor using carbonaceous material as a heat medium,
Petroleum straight-run heavy oil or similar substances at a temperature of 700 to 9
A method for producing pitch suitable as a binder, which comprises thermally decomposing the pitch at 00°C for a reaction time of 0.1 to 10 seconds and separating light oil from the resulting liquid.