DE1592869C3 - Process for the production of furnace black - Google Patents

Description

25th

The invention relates to a method for producing furnace black using a carbon monoxide containing fuel gas, a combustion maintaining gas and a liquid Rußrohstof- jo fes, whereby the carbon black raw material is atomized into the reactor by means of a nozzle and the carbon black raw material is sprayed directly into the flame.

The furnace soot process is characterized, among other things, by the use of a fuel gas the combustion of which generates the temperature necessary for the cracking reaction. The actual Soot raw material is generally sprayed directly into the flame and in this way quickly and evenly heated to the reaction temperature. However, this has the consequence that part of the carbon black raw material increases competes with the fuel gas and burns it. This undesirably increases the soot yield greatly reduced, because most of the fuel gases for their part hardly ever even if the combustion is incomplete are capable of soot formation.

There are constructive measures known to ensure that by relatively good spatial separation This side reaction is suppressed by the cracking reaction of the energy-generating flame. In In this case, the soot raw material is not in the flame itself, but in its hot exhaust gases sprayed.

From US-PS 33 22 506 it is known to use carbon monoxide in the production of furnace carbon black.

From US-PS 30 76 695 it is known to use carbon monoxide instead of air to maintain the combustion To use gas in the manufacture of furnace carbon black.

From US-PS 30 51556 is known in the ω Manufacture of furnace black using oxygen-enriched air.

From GB-PS 7 78 207 it is known, carbon monoxide and hydrogen-containing exhaust gases from the furnace soot reaction to be used again for the production of furnace black.

From GB-PS 6 78 243 it is known that the exhaust gases from the furnace soot reaction are hydrogen and

Contain carbon monoxide.

Surprisingly, it has now been found that there is practically complete combustion of the gas can also be achieved with the simple construction described first, if the fuel gas is expedient selects. Indeed, the various flammable gases in question differ among the Conditions of the furnace soot process in its described, simple form considerably with regard to their degree of combustion.

The invention relates to a process for the production of furnace carbon black using a Fuel gas containing carbon monoxide, a combustion sustaining gas and a liquid one Soot raw material, whereby the carbon black raw material is atomized into the reactor by means of a nozzle and the Soot raw material is sprayed directly into the flame, which is characterized in that for Increase of the soot yield with a soot of constant surface a fuel gas consisting of at least 50 % By volume carbon monoxide is used.

Carbon monoxide also practically burns then, unlike most other combustible gases completely if it emerges from an annular gap in the immediate vicinity of the soot raw material nozzle, that is when the carbon black raw material is sprayed directly into the temperature-generating gas flame.

This also applies to a large extent in the event that the combustion process and the splitting of raw materials are separated are.

A series of tests with benzene as the carbon black raw material resulted, for. B. for different fuel gases the following degrees of combustion:

Coal gas 62% hydrogen 64% methane 73% LPG (propane / butane) 75% Carbon monoxide 99%

In addition, carbon monoxide has the highest equivalent calorific value of the gases mentioned, namely

6040 kcal / Nm ³ O2, compared e.g. B. with
Hydrogen 5160 kcal / Nm ³ O ₂ ,
Methane 4300 kcal / Nm ³ O ₂ ,
and propane 4450 kcal / Nm ³ O2

This special position of carbon monoxide has some very decisive consequences:

1) In contrast to the other gases mentioned, carbon monoxide can increase the furnace temperature increase, even if the amount of air supplied remains constant.

2) On the other hand, if you want the furnace temperature to be at a certain, predetermined value hold, you can even reduce the amount of air supplied to the reaction while the amount of CO is increased. This means a significantly greater increase in the soot yield than with other gases.

3) Proceed as indicated under 2), but do not rely on a certain oven temperature, but on a certain soot surface value, the yield also increases with an increasing amount of carbon monoxide with a constant surface.

The beneficial effect of carbon monoxide can be intensified if the combustion air is used Oxygen adds. In this case it falls for one

A certain amount of total oxygen removes part of the nitrogen ballast, which makes up the main part of natural air and, although chemically inert, has to be heated up. With oxygen enrichment, the furnace temperature, thus rises again without ^r> that the energy primarily generated in the flame would have increased, and without that the process total amount of oxygen supplied would have been increased. On the contrary, if you want to set a certain furnace temperature or specific soot surface, the total amount of oxygen in relation to the amount of carbon black raw material must even be reduced with the increasing oxygen concentration, which means a further increase in the yield.

In a preferred embodiment, | -> use air containing 22 to 40% by volume of oxygen as the combustion maintaining gas, wherein the total oxygen content increases with the increasing oxygen concentration of the gas maintaining the combustion in relation to the amount of carbon black raw material _> o lowers.

The particularly strong yield-increasing effect of carbon monoxide is also noticeable when if it is not used in the pure state, but only the majority of the fuel gas j "> matters.

Examples

1) In a furnace of the usual design, the following were introduced:

25.1 kg soot oil / h, 16.0 Nm ³ atomizing air / h,
78.5 Nm ³ combustion air / h,
23.0 Nm ³ carbon monoxide / h.

A carbon black ^{with a specific surface area of 97 m 2} / g was obtained with a yield of 65.7%, based on the weight of the carbon black oil used, ie 16.5 kg carbon black / h.

2) In the same oven as in Example 1, -to was introduced:

Tabel

35.4 kg soot oil / h,
16.0Nm ³ atomizing air / h,

33.5 Nm ^{3 more} natural combustion air

Composition / h,
10.5 Nm ³ pure oxygen / h,
32.3 Nm ³ carbon monoxide / h.

The total amount of oxygen was therefore 20.9 NmVh, and the oxygen content of the entire nitrogen-oxygen mixture was thus 34.3% by volume. A carbon black ^{with a specific surface area of 102 m 2} / g was obtained with a yield of 75.5%, based on the weight of the carbon black oil used, that is to say 26.7 kg carbon black / h.

3) In the same furnace as in example 1 and 2 were introduced:

25.0 kg soot oil / h,

16.0 Nm ³ atomizing air / h,

77.9 Nm ³ combustion air / h,

23.0 Nm ³ fuel gas / h, consisting in equal parts by volume of carbon monoxide and hydrogen.

A carbon black ^{with a specific surface area of 101 m 2} / g was obtained with a yield of 60.3%, based on the weight of the carbon black oil used, that is to say 15.1 kg carbon black / h.

The table compares the results of Examples 1, 2 and 3. This is used for further explanation Example 4 in the table.

From the table it can be seen that a decrease in the amount of the combustion entertaining gas and at the same time increasing the amount of fuel gas (carbon monoxide - example 4 in Compared to Example 1) an increase in the soot yield with a constant BET surface area is obtained.

There is also an increase in the soot yield with a constant BET surface area if the oxygen concentration is considered the combustion air increases and at the same time the ratio of total oxygen to Soot raw material quantity decreases (Example 1 and Example 2).

example 1 Example 2 Example 3 Example 4 Bre Fuel gas composition CO CO + O ₂ CO + H ₂ CO Combustion air volume m ³ / h 78.5 33.5 77.9 80.3 Atomizing air quantity m ³ / g 16.0 16.0 16.0 16.1 Soot oil quantity kg / h 25.1 35.4 25.0 25.0 Fuel gas quantity m '/ h 23.0 32.3 23.0 17.5 Amount of oxygen (additional) nrVh - 10.5 - - Soot amount kg / h 16.5 26.7 15.1 14.3 Surface area (carbon black) m ² / g 97 102 101 99 Yield% by weight kg carbon black / kg raw material 65.7 75.5 60.3 57.2 O ₂ m ³ / h total amount 19.9 20.9 19.7 20.2 O ₂ / fuel gas (theoretical) 11.5 16.2 11.5 8.8 Oxygen consumption by fuel gas m ³ / h 11.5 16.2 9.4 8.8 O ₂ excess m ³ / h 8.4 4.7 10.3 11.4 O ₂ excess / soot oil 0.33 0.13 0.41 0.46 Theoretical O ₂ excess / soot oil 0.33 0.13 0.32 0.46 Total O ₂ / soot oil 0.8 0.6 0.79 0.81

Claims (2)

Patent claims: 1. A process for the production of furnace carbon black using a carbon monoxide containing one Fuel gas, a combustion maintaining gas and a liquid soot raw material, wherein the carbon black raw material is atomized into the reactor by means of a nozzle and the carbon black raw material is sprayed directly into the flame, characterized in that to increase the soot yield with a soot with a constant surface area is a fuel gas consisting of at least 50% by volume carbon monoxide is used. 2. The method according to claim 1, characterized in that the combustion is used as the entertaining gas air, which contains 22 to 40 vol .-% oxygen, is used with increasing oxygen concentration of the gas maintaining the combustion the total proportion of oxygen in relation to the amount of carbon black raw material.