DE1467480C3 - Process for the production of furnace soot with a given module - Google Patents

Description

The invention relates to a method for producing furnace soot with a given module by pyrolysis and / or partial combustion of hydrocarbons.

Oven soot is often mixed into rubber / mixtures, to control their properties. Particular attention is paid to the consistent quality of the Oven soot is important because it helps keep the "15-minute and 30-minute module" of the rubber product constant is guaranteed. However, such a module is difficult to keep constant because it over the soot quality from the quality of the oil used, which is defined by the BMC index, from air pressure and humidity changes and other often uncontrollable factors that change slowly, depends.

A method is already known according to which the structure of carbon black and thus the modulus value, the carbon black Give rubber compounds, is moaned by Fission oil, an alkali metal or an alkali metal compound is added. The ones introduced into the reactor Quantities have to be precisely dosed and very small. Since the amount of splitting oil added compared to the The amount of alkali compound added is very large, causing a slight change in the amount added Quantity already shows a large change in module, which creates extremely difficult control and dimension problems result. Since alkali metal compounds are generally difficult or insoluble in oil, there is always the risk of complete or partial separation, so that a homogeneous distribution in the Fission oil becomes almost impossible. In addition, alkali metal compounds have the disadvantage that they Accelerate corrosion of ferrous metals and in the case of silicon-containing refractory materials as Flux work.

The object of the present invention is therefore to provide a process for the production of To create furnace soot with a given module, which makes it possible to use a simple control without Use of alkali metal compounds to keep the module constant.

This object is achieved according to the invention in that the reaction mixture is longitudinally at a first point the flow line through the reaction portion of the furnace is quenched to retard the reaction, however not to terminate, with the inflow of quench fluid to this first location to produce a higher modulus and to generate a

ίο lower modulus is diminished, and that the resulting reaction mixture at a second point along the flow line through the reaction part of the Furnace downstream of the first point is quenched in order to terminate the reaction, said in claim conditions are met.

This has the advantage that no foreign substances have to be added and the setting of the Soot properties can be done reliably and accurately, since the regulation of the relatively large liquid flow rates is possible easily and without a large outlay in terms of equipment. The 15 or 30 minute module can thus be kept constant in a simple manner, whereby the abrasion resistance or the surface, of the soot, measured by the nitrogen absorption method, hereinafter referred to as nitrogen surface area for short, practical is not changed.

If in a furnace whose reaction part has a diameter of 0.3 m and in which the first and second cooling points are approximately 1.5 to 3 m apart, a corresponding amount of water is introduced so that half of the water is supplied to each cooling point, so the temperature of the discharged flue gas is characterized in a range of 930 to below ⁰ C, preferably, degraded about 1315 to about 870 ° C. An increase in the water flowing out through the first quenching point of about 3.5 to 4.0 liters per minute increases the 15-minute module by about 2.8 kgf / cm ² and the 30-minute module by about 1 kgf / cm ² and the abrasion index by only about 1%, while the nitrogen surface area is reduced by less than about 0.5%.

In the following an example embodiment of the invention is explained with reference to the drawing.
F i g. 1 shows a schematic, partially sectioned view of a carbon black furnace and manufacturing plant according to the invention, with individual parts removed;

F i g. FIG. 2 is an enlarged cross-section of the FIG. 1 shown, downstream control valve for Keeping the water pressure constant;

F i g. 3 is a cross section of the FIG. 1 along the line 3-3 in the direction of the arrow;

F i g. 4 is a cross-sectional view of the FIG. 1 along the line 4-4 in the direction of the arrow.

In describing this procedure it is common practice, from the 15 and 30 minute modules, to the abrasion resistance index and to speak of the nitrogen surface area of the soot, with these terms being the Modulus or the abrasion resistance of the rubber test samples is meant in which a constant Amount of carbon black as a filler or solidifying agent is included, and the amount of nitrogen that is contained by the carbon black is adsorbed in a customary standard experiment. The procedures for preparing standard rubber samples and these customary standard experiments are known to be performed.

The furnace shown in FIG. 1, indicated generally at 6, is of the same general type as that in FIG U.S. Patent 2,785,964 (1957). However

the invention can be applied to any other conventional carbon black furnace in which carbon black is pyrolysed and / or incomplete combustion of hydrocarbons is produced, e.g. B. in the U.S. Patent 2971822 (1961).

The furnace 6 may include a generally cylindrical combustion and reaction zone 7, the everywhere the same diameter (not shown) or a combustion section 8 with a larger diameter and a reaction section 9, as shown, may have a smaller diameter. A Supplied hydrocarbons in gas, vapor or sprayed liquid form are converted by heat and / or partially with a free oxygen-containing gas, such as. B. air, burned in the chamber 7. It is preferred to remove the hydrocarbon from the tank 11 through the line 12, the valves 13 and / or 14, To lead preheater and partial or total evaporator 16 and line 17 and axially in spray the chamber 7.

It is unimportant, but generally desirable, to have some air, nitrogen, hydrogen, methane, combustion gas or another inert gas through the line 19 and the annular nozzle 21 in the form of a annular layer and around the nozzle 18 to keep carbon deposits to a minimum, which would otherwise build up on the nozzle 18 and the walls of the annular nozzle 21.

A gas containing free oxygen, such as air, is passed through line 22 and tube 23 into the Combustion section 8 introduced, as best shown in FIG. 3 to either part of the supplied hydrocarbon from the nozzle 18 or with a liquid or gaseous fuel, the was introduced through tubes 24 to burn.

While any hydrocarbon gas, oil or mixture as a feed hydrocarbon passes through the Nozzle 18 and can be supplied as fuel through the tubes 24, it is preferable that the to Hydrocarbon passed through nozzle 18 has a high BMC (Bureau of Mines Correlation Index), the fuel in line 24 may be any oil or natural gas or methane.

From the tank 26 pressurized water from some source, e.g. B. the pump 27, through the lines 28 and 29 to the water quenching spray nozzles 31 and 32 and fed into the reaction zone 9 of the furnace 6. In a reaction section 9 with a diameter of 0.3 m, the first quenching point 31 and the second quenching point 32 are approximately 1.5 to 3 m apart, and the intermediate section 33 of the reaction zone 9 acts as a reaction zone at a lower speed than that upstream of the first cooling point 31 , and this reduced reaction rate depends entirely on how much quenching water is added at the first quenching nozzle 31. For a reaction zone 9 with a smaller diameter, the length of zone 33 is shorter and directly proportional to the diameter of zone 9. For example, for a reaction zone 9 with a diameter of 76 mm, zone 33 is preferably about 30 to 92 cm long and for one Reaction zone about 60 cm in diameter and about 3 to 6 m long. However, the invention can then be used "when the zone 33 is practically of such a length that the smoke flowing through has a relatively short residence time, for example about 0.01 to 10 seconds, in this zone. The second quenching nozzle 32 leads enough water to reduce the temperature of the smoke below about 925 to 930 ⁰ C, preferably to about 870 ° C, at which practically no further reaction occurs in the chamber section 34 or in the line 36, in the usual gas-solid Separation zone 37 which may consist of a cyclone separator as shown or a bag filter (not shown) or any combination of cyclones and / or bag filters and / or electrical precipitators known in the art Line 36 or further quenching with water (not shown) can, if desired, be carried out in line 36 to protect the separation plant 37, but is e not necessary according to the invention. The exhaust gas is discharged from the separation zone 37 through the line 38 for further disposal, and the soot produced flows through the star valve 39 into the line 41.

To deliver water to the first quenching nozzles 31 at a constant predetermined speed a conventional constant pressure downdraft pressure reducing regulating valve is preferred 42 is used which regulates the rate of water flow through line 28. This Pressure can, if desired, be measured by a pressure gauge 45, with the pressure in line 28 downstream of the valve 42 by a screw 43 on the upper part of the valve 42 in a known manner is set. If desired, other known means for supplying the water can be used can be used to the nozzle 31 at a constant predetermined speed.

The valve 42 is shown in FIG. 2 shown in section. It is a valve of the usual type. The locking nut 44 holds the screw 43 in the set position. Is the screw 43 through the thread 46 of the valve 42 screwed in, the pressure on the helical spring 47 increases, whereby the valve head 48 moves downwards and the valve seat 49 opens. The pressure downstream of the valve seat 49 in the space 51 becomes transferred through the tube 52 to the space 53 under the flexible membrane 54, the spring 47 upwards to press and the downward force of the spring 47 and, because of the passage 56, also the Equalize atmospheric pressure. This gives a constant pressure in the nozzles 31 and therefore a constant flow rate of the water through these nozzles.

The flow rate of the water in the line 29 varies with the temperature in 34 at the Thermometer 57, which actuates the temperature-registering control unit 58 and the motor valve 59 to the desired necessary degree opens, and to maintain a predetermined constant temperature at 57, such as it was adjusted by the adjusting screw 61. Such controls are known. If desired, A pressure gauge 62 indicates the actual flow rate of the water through the nozzles 32. the Nozzles 31 and 32 can be calibrated for such flow rates under the given pressures being.

In Fig. 3 tubes 23 are arranged tangentially to the outer wall of the cylindrical chamber 8.

In Figure 4, line 29 supplies four water quenching spray lines 32 with water, which run radially into the cylindrical cooling section 34 of the furnace.

The operation of the furnace is started by supplying oil or gas through the lines 24 and air

14 67 48U

through line 22. Upon ignition, chamber 8 is filled with a spiral flame and / or hot combustion gases filled. The feed hydrocarbon is then fed axially through line 18 into chamber 8 introduced into the center of the hot spiral flame or gas from the tubes 23 and through partially Combustion and / or pyrolysis converted into smoke from soot. A first quenching takes place through Injection of water at 31, which delays the reaction and the entire, in the second reaction zone 33 resulting reaction is reduced. The second quench at 32 sets the temperature of the smoke from the soot down to a temperature below which practically no further reaction takes place. The smoke pours out then from the quenching zone 34 into a gas-solids separation zone 37. Samples of carbon black at 41, which at 37 from the were separated at 38 outflowing effluent gases are examined in standard rubber test samples, to their 15- and / or 30-minute module determine and the screw 43 and nut 44 are adjusted to the pressure at 45 around the to change the amount required so that the module also receives the desired value. More samples of soot from 41 can be examined periodically to determine small changes occurring and the module continue to check what the screw 43 can still be readjusted.

It has been found that a furnace as shown in the drawing, which has a reaction section 9 with a diameter of 0.3 m and nozzles 31 and 32 spaced about 2.3 m apart, takes 15 minutes -Modulus increased by about 2.3 kp / mm ² when the water pressure at 45 increases by 0.7 kp / cm ²

5 or that an increase in the water injected into the first quenching nozzle 31 by about 3.8 l / min results in ^{an increase in the modulus of about 3 kgf / cm 2.} The 30 minute module increases by about 1.2 kp / cm ² if the water pressure increases by 0.7 kp / cm ² at 45, or

ίο an increase of approximately 3.8 l / water per minute in the cooling point 31 results in an increase in the 30-minute module of approximately 1 kp / cm ² . The abrasion index only increases by 0.9% if the water pressure at 45 increases by 0.7 kp / cm ² or by 1.1% if the water flow through the nozzle 31 increases by 3.8 l / min, and the average decrease in the surface is only 0.25 m ² / g with an increase of 0.7 kp / cm ² at 45 or 0.59 m ² / g with an increase in the water throughput through the quenching point 31 of 3.8 l / Min. The rate of reaction may vary for different furnaces and different hydrocarbon oils or gases, but routine experimentation can determine the optimal reaction conditions for each oil.

An advantage of using the simple devices shown is the reduction in the Installation costs, and it was found that this simple system was more reliable and more reliable than a more complicated one works.

1 sheet of drawings

Claims (1)

Claim: Process for the production of furnace soot with a given module by pyrolysis and / or partial combustion of hydrocarbons, characterized in that the reaction mixture is quenched at a first point along the flow line through the reaction part of the furnace to a temperature not below 1315 ° C in order to initiate the reaction to delay, but not terminate, the flow of quench fluid to that first location being increased to produce a higher modulus and decreased to produce a lower modulus, and the resulting reaction mixture at a second location along the flow line through the reaction portion of the furnace downstream from the first location below about 930 ⁰ C, 870 ° C is quenched, preferably to terminate the reaction, wherein the zone is sized between the two Abschreckstellen such that the residence time of the flowing smoke is about 0.01 to 10 seconds.