Method for controlling oxidation of wet beaded carbon black

Abstract

The present invention relates to a method for controlling the oxidation of wet beaded carbon black in a screw conveyor. Surprisingly, it has been found that the motor current used to drive the conveyor screw is an indicator of the breakdown of the wet beaded carbon black during oxidation. The method and control device of the present invention utilizes the motor current to adapt the rotation speed of the screw.

Description

[Technical field]

[0001] The present invention relates to a method for controlling the oxidation of wet beaded carbon black in a screw conveyor. Surprisingly, it has been found that the motor current used to drive the conveyor screw is an indicator of the breakdown of the wet beaded carbon black during oxidation. The method and control device of the present invention utilizes the motor current to adapt the rotation speed of the screw. [Background technology]

[0002] Carbon black is a fine powder that is difficult to store, transport or handle. To circumvent these difficulties, carbon black powder is often provided as pellets or beads having increased bulk density.

[0003] One method for providing these beads is known as wet beading, in which carbon black powder is stirred in water and then dried. Such a method is described in GB 839,918.

[0004] Dry beading in drums and feeding oxidizer directly in the dry beading drum are known in the prior art, but this technology is not applicable to rubber customers due to the low pellet strength of the dry beading product.

[0005] On the other hand, wet-beaded carbon black can be beneficially used in rubber compositions since improved pellet strength is achieved. The oxidation of carbon black and subsequent wet-beading is described in US2019 / 0161621A1. The produced carbon black is ground and subjected to a second reactor to obtain a carbon black / water mixture. The carbon black in the mixture is then oxidized and then beaded in a pelletizer. The resulting oxidized beaded carbon black is transferred to a dryer via a screw conveyor.

[0006] However, a drawback of beading and drying oxidized carbon black is that the degree of oxidation, i.e. the amount of functional groups on the surface of the carbon black beads, decreases during the process. Therefore, it is difficult to control the desired degree of oxidation of the carbon black beads.

[0007] Therefore, a screw conveyor has been developed as an oxidation unit for wet beaded carbon black. Even if the damage of wet beaded carbon black can be reduced in the screw conveyor, a control device and method should be provided that can detect and avoid the damage of beads during oxidation.

[0008] Surprisingly, it has been found that the above objectives can be achieved by a control device and method which detects the motor current required for a set rotational speed, determines the difference between that required motor current and the motor current necessary for that set rotational speed without pellet destruction, and adapts the rotational speed based on that difference. Summary of the Invention

[0009] In particular, the above objective is to determine the rotation speed n(t) of the screw conveyor (200, 300) and the ozone flow rate q for producing oxidized wet beaded carbon black (202). ozone This can be accomplished by a method of controlling the flow rate (n,t) of ozone into the reaction chamber (218) by controlling the flow rate of ozone (q) into the reaction chamber (218), where the screw conveyor (200, 300) includes an electric motor (215) driving a conveyor screw (213) for transporting the wet beaded carbon black (201) from the material inlet (210) toward the material outlet (202) through a reaction chamber (218) containing ozone, the reaction chamber (218) further comprising a flow rate (q) of ozone into the reaction chamber (218). ozoneThe present invention also relates to at least one ozone inlet (216) configured to adjust the rotational speed n(t) of the screw conveyor (200, 300) and the ozone flow rate q(t) for producing oxidized wet beaded carbon black (202), the method including current regulating power control of the motor according to a predetermined correlation of set points for a particular carbon black product. ozone The present invention relates to a control device (900) for controlling the wet beaded carbon black (201) from the material inlet (210) toward the material outlet (202) through a reaction chamber (218) containing ozone, the reaction chamber (218) further comprising an ozone flow rate q into the reaction chamber (218). ozone (n,t) and the controller (900) is configured to perform current regulating power control of the motor in response to a predetermined correlation of set points for a particular carbon black product.

[0010] These and any other features and advantages of the present invention are described in more detail in the following description, figures, embodiments and claims. [Brief description of the drawings]

[0011] [Figure 1] A method (100) for producing oxidized wet beaded carbon black (202). [Diagram 2] The inner part of a screw conveyor (200, 300) for producing oxidized wet beaded carbon black. [Diagram 3] The outer part of a screw conveyor (200, 300) for producing oxidized wet beaded carbon black. [Figure 4] Part of the conveyor screw (400). [Diagram 5]A portion of the conveyor screw (500) having a second helical conveyor blade (501) forming a circumferential clearance (503). [Figure 6] A portion of a conveyor screw (600) having sections (601, 602, 603) of different helical conveyor blades (501, 502). [Figure 7] A portion of the conveyor screw (700) having a second helical conveyor blade (501) and turners (702, 703) forming a circumferential clearance (503). [Figure 8] A portion of a conveyor screw (700) having a second helical conveyor blade (501) and turners (702, 703) that form a circumferential clearance (503), including the angle and direction of rotation. [Figure 9] Image of oxidized wet beaded carbon black (202). [Figure 10] A method for controlling the rotational speed n(t) of the screw conveyor (200, 300) and the ozone flow rate qozone(n,t). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] It was found that the rotation speed of the screw conveyor affects the pellet strength, pellet abrasion and fines content, and therefore the pellet breakage. If the energy consumption of the electric motor is too high, an increase in pellet breakage will be observed. Therefore, devices (or control devices) and methods have been developed that can adapt to the conditions during oxidation. It is now possible to continuously oxidize the wet beaded carbon black in a screw conveyor as an oxidation unit without damaging the pellets. Thus, the resulting oxidized wet beaded carbon black has improved pellet strength, lower pellet abrasion, as well as lower fines content. Furthermore, the screw conveyor utilizing the method and apparatus of the present invention is more versatile, since it can adapt to increased inputs of wet beaded carbon black feed by increasing or decreasing the screw rotation speed. It is desirable that the output of the oxidized wet beaded carbon black is maximized without adversely affecting the properties of the beads.

[0013] Therefore, the rotation speed of the screw conveyor n(t) and the ozone flow rate q for producing oxidized wet-beaded carbon black are ozone A control device of the present invention is provided for controlling (n,t) where the screw conveyor includes an electric motor driving a conveyor screw, the conveyor screw transporting the wet beaded carbon black from a material inlet toward a material outlet while passing through a reaction chamber containing ozone, the reaction chamber further comprising an ozone flow rate q ozone (n,t) and the controller is configured to perform current regulating power control of the motor in response to a predetermined correlation of set points for a particular carbon black product.

[0014] The control device can further include a primary control device, means for detecting and / or monitoring the actual motor current during operation, means for detecting and / or monitoring and / or controlling the rotational speed, and data storage means including a database for the product-specific power setting values of the screw conveyor.

[0015] The control device further includes a flow controller configured to control the flow rate q ozone,set (n,t) based on the set ozone flow rate q ozone (n,t).

[0016] Furthermore, the present invention relates to a method for controlling the rotational speed n(t) and the ozone flow rate q ozone (n,t) of a screw conveyor for producing oxidized wet-beaded carbon black, where the screw conveyor includes an electric motor for driving the conveyor screw, the conveyor screw conveys wet-beaded carbon black from a material inlet to a material outlet while passing through a reaction chamber containing ozone, and the reaction chamber further includes at least one ozone inlet configured to adapt the ozone flow rate q ozone (n,t) into the reaction chamber, and the method includes current adjustment power control of the motor according to a predetermined correlation of set values for a specific carbon black product.

[0017] The current adjustment power control of the motor is used to adapt the actual rotational speed n(t) of the screw of the screw conveyor and the actual motor current I(t). The adaptation of n(t) and I(t) depends on a predetermined correlation of set values including the set rotational speed n set (t) and the correlated set motor current I set (t), preferably for a specific carbon black product.

[0018] At least one ozone inlet configured to adapt the ozone flow rate q ozone (n,t) into the reaction chamber is such that the ozone flow rate qozone It may include a valve that can adapt (n,t).

[0019] The current regulating power control can be used to adapt the rotational speed of the conveyor screw based on the energy consumption of the electric motor of the screw conveyor by comparing the actual energy consumption with a predetermined energy consumption, preferably measured for a plurality of rotational speeds for the particular oxidized carbon black to be produced, the predetermined energy consumption preferably being stored in a look-up table.

[0020] Further, the method may include the steps of: (A) determining from the predetermined correlation a set rotation speed n for the particular oxidized wet beaded carbon black to be produced; set (t) and the set ozone flow rate q ozone,set (B) detecting an actual motor current I(t) of the electric motor during operation; and (C) comparing the actual motor current I(t) with a first predetermined set motor current I(t) from the above-mentioned predetermined correlation of set values. set (D) based on the result of the comparison (ΔI), preferably using a primary control device, set the rotational speed n set (E) determining a corrected second set motor current and a corrected set ozone flow rate based on the adjusted rotation speed; (F) calculating a set ozone flow rate q from the rotation speed n(t). ozone,set (n,t), and (G) adapting the ozone flow rate into the reaction chamber accordingly.

[0021] The above control device and method preferably utilize a screw conveyor, where conditions are measured for the various oxidized wet beaded carbon blacks desired to be produced. Thus, the user should collect data that is optimal for the production of the desired oxidized wet beaded carbon black for a particular screw conveyor. The data is collected at a set rotation speed n set(t) and the respective set motor currents I required for the electric motors of the screw conveyors. set (t) and stored in the look-up table. In other words, the look-up table data for the oxidized wet beaded carbon black to be produced can take into account the screw conveyor. For example, a screw conveyor is fed with wet beaded carbon black, several different rotational speeds are applied, and the corresponding motor currents are measured and stored. Thus, the look-up table can be used to determine the rotational speed n for a particular screw conveyor. set (t) and the motor current I set The correlation value of (t) can be stored (e.g., a first lookup table). The correlation between the rotation speed and the rotation speed is calculated based on the set rotation speed n set (t) and the set motor current I set (t). In addition, for each correlation or relationship, the set ozone flow rate q ozone,set (n,t) is also stored in a lookup table (e.g., a second lookup table). ozone,set (n,t) define the desired degree of oxidation and depend on the desired oxidized wet beaded carbon black to be produced. However, the rotation speed affects the duration of the wet beaded carbon black in the reaction chamber and therefore the degree of oxidation. In general, the longer the wet beaded carbon black is in the reaction chamber of the screw conveyor, the higher the degree of oxidation (for the same ozone flow rate). Therefore, the set ozone flow rate q ozone,set (n,t) is the set rotation speed n for the production of the desired oxidized wet beaded carbon black. set During the oxidation process, the flow sensor measures the ozone flow rate q ozone (n,t) can be measured, which allows the flow controller to determine the ozone flow rate q ozone (n,t) or set ozone flow rate q ozone,set (n,t) can be adjusted.

[0022] Therefore, the look-up table is used to find the corresponding set rotation speed n set (t) and the set motor current I set Data relating to (t) and the set ozone flow rate q ozone,set Preferably, the first lookup table includes data including n (n, t) for at least one particular product. set (t) and I set The second lookup table may include data representing multiple correlation values ​​of n(t) and q(t). ozone,set Preferably the or each look-up table includes data representing a plurality of correlation values ​​of (n,t) for a set rotation speed n set (t) and the set motor current I set (t) data, where the set ozone flow rate q ozone,set The lookup table includes several data points, e.g., 2 to 1000 data points, related to the data including (n,t), each data point being associated with a different rotation speed. In other words, the lookup table includes a set rotation speed n for the production of a desired oxidized wet beaded carbon black. set (t), set motor current I set (t) and the set ozone flow rate q ozone,set It is desirable to include data on (n,t). However, the database or data storage means including the look-up table or the first and / or second look-up tables can extrapolate data points that are not explicitly measured. The look-up table or the first and / or second look-up tables preferably include data on the correlated set rotation speed n for each specific oxidized wet beaded carbon black product. set (t) and the set motor current I set (t) data, where the set ozone flow rate q ozone,set Note that the lookup table may contain several data points, e.g., 2 to 1000 data points, for the data including (n,t), each data point for a different rotation speed. The lookup table may store a different set of data points for each desired product.

[0023] The lookup table is for the set rotation speed n set (t) and the set motor current I set (t), as well as the set rotation speed n for the production of the desired oxidized wet beaded carbon black. set The required set ozone flow rate q (t) ozone,set It can include data on (n,t). Set rotation speed n set (t) and the set motor current I set (t), as well as the set rotation speed n for the production of the desired oxidized wet beaded carbon black. set The required set ozone flow rate q (t) ozone,set (n,t) can be measured for each desired oxidized wet beaded carbon black produced in the screw conveyor. Set rotation speed n set (t) and the set motor current I set (t), as well as the set rotation speed n for the production of the desired oxidized wet beaded carbon black. set The required set ozone flow rate q (t) ozone,set (n,t) can be measured for each desired oxidized wet beaded carbon black produced in the screw conveyor and stored in a look-up table. Preferably, the first look-up table includes n for at least one specific product. set (t) and I set The second lookup table may include data representing multiple correlation values ​​of n(t) and q(t). ozone,set The data may include data representing multiple correlation values ​​of (n,t) for a particular rotation speed n set If not stored for (t), a database or look-up table is used to determine the correlated set motor current I set (t) and the set rotation speed n set It is also possible to extrapolate the data points in (t).

[0024] The look-up table data for the oxidized wet beaded carbon black being produced should take into account screw conveyor conditions at which the wet beaded carbon black is not broken down. However, as discussed above, it is preferred that multiple data points are stored in the look-up table, with each data point being associated with a particular rotation speed at which the wet beaded carbon black is preferably not broken down.

[0025] Generally, the user can select the desired oxidized wet beaded carbon black to be produced, and thereby set the rotation speed n set (t) and the set ozone flow rate q ozone,set (n,t) is received. Set rotation speed n set (t) is used in the electric motor, and the set ozone flow rate q ozone,set (n,t) applies.

[0026] The result (ΔI) in step (D) can be used in the next step (E) to determine a corrected second set motor current and a corrected set ozone flow rate based on the adjusted rotation speed. For example, the result ΔI or difference current ΔI is calculated by subtracting the motor current I(t) from the set motor current I set If the current difference ΔI is less than 0, the set rotation speed n set Similarly, the difference current ΔI can be increased by increasing the motor current I(t) to the set motor current I set If the current difference ΔI is greater than 0, the set rotation speed n set (t) can be reduced.

[0027] Set rotation speed n setThe adjustment of rotational speed n(t) to n(t) can be made by decreasing or increasing the rotational speed n(t) by a predetermined increment, preferably 1-99%, preferably 2-80%, more preferably 3-50%, and most preferably 5-10%. Typically, an electric motor drives the conveyor screw at a rotational speed n(t). Preferably, the adjustment of rotational speed n(t) is made by decreasing the rotational speed n(t) by an amount that is based on the result ΔI or difference current ΔI. For example, the result ΔI or difference current ΔI is determined by the motor current I(t) decreasing to a set motor current I set If the measured value indicates that the wet beaded carbon black is 10% lower than the measured value (t), the rotation speed n(t) can be reduced by 10%. However, the specific reduction is not limited to a specific value. Thus, the method and apparatus of the present invention can adjust the rotation speed during oxidation to prevent the destruction of the wet beaded carbon black. Furthermore, the fluctuation of the wet beaded carbon black feed can be compensated for. The amount of wet beaded carbon black injected into the screw conveyor via the material inlet can also be controlled and / or measured.

[0028] The adjustments are made during the oxidation of the wet beaded carbon black in the screw conveyor. If a different product is desired or if a different degree of oxidation is required, new user input may be required. If a different product is desired, a different set of data points is received from the database or data storage means.

[0029] Adjustment of rotation speed or rotation speed n set The reduction in (t) can be carried out for a predetermined time, and can be carried out intermittently at intervals of preferably 1 second to 30 minutes, preferably 5 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and most preferably 1 minute to 5 minutes.

[0030] In general, the rotation speed of the conveyor screw is adjusted in response to detecting the actual motor current based on a predetermined correlation between the motor current and the rotation speed for a particular carbon black product. Additionally, the ozone flow rate is desirably adjusted in response to the adjusted rotation speed based on a predetermined correlation between the rotation speed and the ozone flow rate for a particular carbon black product. For example, in step (E), n values ​​for at least one particular product are selected from the first lookup table and / or the second lookup table. set (t) and I set Data is received representing a plurality of correlation values ​​of n(t) for the set rotation speed n(t) adjusted to n(t) in step (D). set For (t), the corresponding predetermined motor current I set (t) is used. The relative set rotation speed n set This correlates to the desired set motor current I set (t) is the new set motor current I(t) for further comparison with the actual motor current I(t). set (t) can be used.

[0031] "Carbon black" as referred to herein means carbon produced by thermal oxidative pyrolysis or thermal splitting of a carbon feedstock, and which is substantially composed of carbon, for example, more than 80%, more than 90% or more than 95% by weight based on the total amount. Various industrial methods are known for producing carbon black, such as the furnace process, the gas black process, the acetylene black process, the thermal black process or the lamp black process. The production of carbon black is well known per se in the art and is reviewed, for example, in J.-B. Donnett et al., "Carbon Black: Science and Technology", 2nd Edition, and is further described below. Carbon black refers to carbon black in powder form, unless otherwise stated. Wet carbon black refers to carbon black powder containing water and optionally a binder. Beaded carbon black refers to either dry or wet beaded carbon black. Oxidized wet beaded carbon black refers to carbon black produced according to the present invention, where, unless otherwise stated, the carbon black is first beaded and then oxidized. The terms bead and pellet are used synonymously. Oxidized carbon black generally has significant oxygen content and oxygen-containing functional groups, including, but not limited to, quinone, carboxy, phenol, lactol, lactone, anhydride and ketone groups. The screw conveyor according to the present invention is a screw conveyor designed for the oxidation of carbon black beads. Diameter always refers to the inside diameter unless otherwise specified.

[0032] 1. A method for producing oxidized wet-beaded carbon black, comprising the steps of: (a) providing carbon black; (b) wet-beading the carbon black obtained in step (a) to obtain wet-beaded carbon black; and (c) oxidizing the wet-beaded carbon black obtained in step (b) in a reaction chamber to obtain oxidized wet-beaded carbon black.

[0033] The resulting oxidized wet beaded carbon black has, among other things, high pellet crush strength and low pellet attrition. At the same time, the volatile content can be controlled during production without the risk of losing volatiles (i.e., reducing the degree of oxidation) during the drying or beading process.

[0034] The oxidation in step (c) can be carried out in a screw conveyor comprising a reaction chamber as mentioned in step (c) and at least one ozone inlet for supplying ozone to the reaction chamber. The wet beaded carbon black obtained in step (a) can be fed to the reaction chamber of the screw conveyor, in particular the screw conveyor. The screw conveyor is further described below.

[0035] The speed of the screw (screw of the screw conveyor) is desirably 0.01 to 10 rpm, preferably 0.1 to 5 rpm, more preferably 0.2 to 3 rpm, even more preferably 0.3 to 2.5 rpm, and most preferably 0.4 to 1 rpm. In general, the screw rotation speed is not limited to a specific value. The screw rotation speed may have an effect on the properties of the oxidized wet beaded carbon black produced. For example, a lower screw rotation speed results in a higher volatile content of the oxidized wet beaded carbon black produced, since the wet beaded carbon black resides longer in the reaction chamber. Thus, if the desired volatile content is to be constant, a lower screw rotation speed may require a lower supply of ozone (or ozone flow rate, such as a set ozone flow rate). The screw rotation speed is desirably set to a value at which no or only minimal bead destruction is observed. The optimal rotation speed may depend on the particular wet beaded carbon black material to be oxidized. Therefore, it is recommended to measure the optimal rotation speed of the screw of the particular screw conveyor as well as the wet beaded carbon black. The measured value is the set rotation speed n set (t) and the set rotation speed n set Required motor current Iset (t) in the look-up table. As described above, the set rotation speed n set (t) should be a rotation speed at which no or only minimal bead breakage is observed. Additionally, the required flow of oxidizing agent (such as ozone) can be determined and stored in a lookup (e.g., a second lookup table) for the desired oxidized wet beaded carbon black. During the oxidation step (c), at least 80%, preferably 90%, and more preferably 95% of the pellets should not be broken down.

[0036] The carbon black in step (a) is generally provided as a powder. Any type of carbon black powder material, such as acetylene black, channel black, furnace black, lamp black and thermal black, can be used according to the present invention. Furnace black is particularly preferred. A crusher can further pulverize the carbon black powder before wet beading.

[0037] For oxidation, any oxidizing agent can be used. The method according to the invention is not limited to a specific oxidizing agent. Ozone, H2O2 and / or NOx (such as HNO3) can be used for oxidation. Ozone is particularly preferred since it can be easily obtained from an ozone generator using air. Furthermore, by using ozone instead of NOx, a reduction in oxidation / corrosion of the equipment is observed. This is particularly useful for screw conveyors that include moving parts such as screws. However, if specific functional groups are desired on the surface of the carbon black, a different oxidizing agent such as NOx can be used.

[0038] High concentrations of ozone can be used in the reaction chamber for oxidation. The concentration or amount of ozone in the reaction chamber depends on the degree of oxidation (amount of volatiles) desired. The concentration of ozone should be highest at the ozone inlet and decrease towards the outlet of the produced oxidized wet beaded carbon black. It is desirable that the ozone reacts completely with the wet beaded carbon black. Therefore, it is desirable that there is substantially no ozone at the outlet of the reaction chamber, or that the amount of ozone is less than 0.1% by weight of the gas present at the outlet of the reaction chamber. The ozone concentration or amount of ozone can be adjusted by the ozone flow rate into the reaction chamber. It is desirable that 0.1 to 95% by weight, preferably 0.5 to 20% by weight, more preferably 1 to 15% by weight, even more preferably 1.5 to 15% by weight, and most preferably 2 to 10% by weight of the gas present in the reaction chamber is ozone, and / or the gas provided to the reaction chamber via the ozone inlet is ozone. Usually, 0.5 to 5% by weight of the gas present in the reaction chamber is ozone. In particular, ozone-enriched air is used for the oxidation step containing the amounts or concentrations referred to herein. The concentration of ozone in the reaction chamber or provided to the reaction chamber via the ozone inlet is between 1 and 300 g / m 3 , for example 1 to 200 g / m 3 , 1~50g / m 3 , 1~60g / m 3 , 15~60g / m 3 , 15~60g / m 3 , or 15 to 50 g / m 3The ozone concentration or amount of ozone in the reaction chamber can take into account the concentration gradient in the reaction chamber. Thus, the overall ozone concentration or amount of ozone in the entire reaction chamber is generally taken into account. Thus, as long as the overall concentration complies with the above range, the ozone concentration at the ozone inlet can be above the above maximum value or below the above minimum value at the outlet. The ozone flow rate can be 100-50000 g / h, for example, 300-5000 g / h, 300-30000 g / h, 500-10000 g / h, 800-5000 g / h, 5000-30000 g / h, or 1000-30000 g / h. The ozone flow rate can be adjusted as desired depending on the degree of oxidation. Furthermore, the ozone flow rate depends on the size of the screw conveyor. When a large screw conveyor is used, a higher ozone flow rate should be utilized. The ozone provided to the reaction chamber via the ozone inlet can be derived from air or liquid oxygen.

[0039] Generally, the ozone concentration is adjusted / controlled such that the volatile content measured at 950°C is 1-25 wt%, e.g., 1.5-20 wt%, 1-10 wt%, 1.5-10 wt%, 1.5-20 wt%, 2-10 wt%, 2-15 wt%, 5-15 wt%, 2.5-10 wt%, 3-7 wt%, or 3.5-7 wt%. Thus, the ozone concentration in the reaction chamber should be adjusted / controlled such that the desired volatile content is achieved. For example, the ozone flow rate to the reactor can be adjusted / controlled to adjust / control the ozone concentration. The ozone concentration refers to the ozone concentration when the wet beaded carbon black is processed. For example, the ozone concentration in the reactor or reactor chamber.

[0040] The volatile content at 950°C can also be adjusted / controlled by the air flow rate and residence time of the wet beaded carbon black. The residence time of the wet beaded carbon black can be adjusted by the feed rate of the wet beaded carbon black and / or the screw rotation speed.

[0041] Typically, the air flow rate is adjusted / controlled such that the volatile content measured at 950° C. is between 1-25 wt%, e.g., between 1.5-20 wt%, 1-10 wt%, 1.5-10 wt%, 1.5-20 wt%, 2-10 wt%, 2-15 wt%, 5-15 wt%, 2.5-10 wt%, 3-7 wt%, or 3.5-7 wt%, e.g., air flow rate into the reaction chamber.

[0042] Typically, the residence time of the wet beaded carbon black is adjusted / controlled such that the volatile content measured at 950° C. is 1-25 wt%, e.g., 1.5-20 wt%, 1-10 wt%, 1.5-10 wt%, 1.5-20 wt%, 2-10 wt%, 2-15 wt%, 5-15 wt%, 2.5-10 wt%, 3-7 wt%, or 3.5-7 wt%. e.g., residence time of the wet beaded carbon black in the reaction chamber.

[0043] Typically, the screw rotation speed is adjusted / controlled such that the volatile content measured at 950° C. is 1-25 wt%, e.g., 1.5-20 wt%, 1-10 wt%, 1.5-10 wt%, 1.5-20 wt%, 2-10 wt%, 2-15 wt%, 5-15 wt%, 2.5-10 wt%, 3-7 wt%, or 3.5-7 wt%, e.g., the screw rotation speed of a screw conveyor.

[0044] The ozone concentration, air flow rate, residence time of the wet beaded carbon black, and / or screw rotation speed can be adjusted / controlled such that the volatile content measured at 950° C. is 1-25 wt%, e.g., 1.5-20 wt%, 1-10 wt%, 1.5-10 wt%, 1.5-20 wt%, 2-10 wt%, 2-15 wt%, 5-15 wt%, 2.5-10 wt%, 3-7 wt%, or 3.5-7 wt%.

[0045] The volatile content of the wet beaded carbon black measured at 950°C is preferably 2.2 to 25% by weight, more preferably 2.2 to 20% by weight, more preferably 2.2 to 15% by weight, even more preferably 3 to 15% by weight, and most preferably 3 to 10% by weight.

[0046] Furthermore, the screw conveyor may include a means for generating ozone. The means for generating ozone should be connected to at least one ozone inlet.

[0047] The volatile content at 950 °C can be measured using a thermogravimetric analyzer (TGA-701) manufactured by Fa.LECO Instruments according to the following procedure. The sample pan is dried at 650 °C for 30 min. The carbon black material is stored in a desiccator with desiccant prior to measurement. The baked-out sample pan is loaded into the instrument, tared, and filled with 0.5 g to 10 g of carbon black material. The oven of the TGA instrument loaded with the sample-loaded pan is then gradually heated to 105 °C by automated software control to dry the sample until a constant mass is achieved. The pan is then closed with a lid, the oven is purged with nitrogen (99.9 vol.% grade), and heated to 950 °C. The oven temperature is maintained at 950 °C for 7 min. The volatile content at 950 °C is calculated using the following formula:

number

[0048] The weight ratio of the wet beaded carbon black (e.g., dry weight of carbon black) to the ozone for oxidation in step (c) should be greater than 1, preferably greater than or equal to 3, more preferably greater than or equal to 4. In particular, the weight ratio of the wet beaded carbon black (e.g., dry weight of carbon black) to the ozone for oxidation in step (c) should be 1:1 to 15:1, preferably 1.1:1 to 13:1, more preferably 1.5:1 to 10:1, even more preferably 2:1 to 8:1, and most preferably 3:1 to 6:1.

[0049] The temperature of the oxidation in step (c) is 10-60°C, preferably 20-50°C, more preferably 30-45°C. In particular, the temperature in the reaction chamber is 10-60°C, preferably 20-50°C, more preferably 30-45°C. The temperature in the screw conveyor can be controlled by a liquid or fluid, e.g. water, attached to the screw conveyor or the barrel of the screw conveyor. Thus, the screw conveyor can include a temperature control unit for cooling or heating. It is desirable that the temperature for the reaction chamber or oxidation is controlled so that no loss of volatiles occurs during the oxidation. In general, the oxidation of wet beaded carbon black is an exothermic reaction and heat should be dissipated. This may be particularly relevant for processes in which highly oxidized carbon black or highly oxidized wet beaded carbon black is obtained. However, in processes in which less oxidized carbon black is obtained, it may be beneficial to transfer additional heat to the reaction chamber for the oxidation step.

[0050] Wet beading (b) generally includes the steps of (b1) treating carbon black with water to obtain wet carbon black, (b2) beading the wet carbon black to obtain beaded carbon black containing water, and (b3) drying the beaded carbon black to obtain wet beaded carbon black (201).

[0051] The moisture content of the wet beaded carbon black should be less than 10% by weight, more preferably less than 5% by weight, even more preferably 0.001-4% by weight, and most preferably 0.01-1% by weight. This means that after the aforementioned drying step, most of the moisture content is removed, so that the oxidation is carried out using an already dried wet beaded carbon black. Therefore, it is preferred that the oxidation is carried out using a dried wet beaded carbon black.

[0052] Wet beading is usually carried out in a "wet beading box" equipped with a number of agitating pins that extend longitudinally through the body and are attached to a shaft that rotates at speeds up to about 240 rpm depending on the type of carbon black powder. The action of the pins causes the wet carbon black to form into beads or pellets, which are then dried in a dryer. However, any type of wet beading equipment can be used for wet beading.

[0053] The weight of water used for beading is usually equal to the weight of the carbon black powder to be beaded. The range can be 5% to 1000% by weight based on the total weight of the carbon black. Preferably, it is 20 to 200% by weight, more preferably 50 to 150% by weight, based on the total weight of the carbon black.

[0054] The water for wet beading usually contains a binder, preferably the binder contains molasses and / or lignosulfonate. Such binder is uniformly dispersed throughout the beads. The binder can increase the crush strength and packing point of the carbon black beads. The binder can be present in an amount of 0.01-1.00% by weight, preferably 0.05-0.9% by weight, more preferably 0.1-0.80% by weight, based on the total weight of the carbon black, especially the carbon black for wet beading. The weight ratio of the binder to the carbon black for wet beading is 1 / 10000-1 / 100, preferably 1-1 / 2000-1 / 110, more preferably 1 / 1000-1 / 125.

[0055] Air flow rate to reaction chamber is 5~1000Nm 3 / h, e.g. 5-200Nm 3 / h, 10~150Nm 3 / h, 15~100Nm 3 / h, 20~50Nm 3 / h, 10~600Nm 3 / h, 15~300Nm 3 / h, 10~600Nm 3 / h, 100~800Nm 3 / h, or 200-600Nm 3 / h. The air flow rate generally depends on the set ozone flow rate. In addition, the air flow rate depends on the size of the reaction chamber. Larger reaction chambers usually require higher air flow rates. The wet beaded carbon black feed to the reaction chamber can be 0.01-1000g / s, e.g., 1-500g / s, 100-600g / s, 0.05-50g / s, 0.08-20g / s, or 0.08-5g / s.

[0056] The average pellet crushing strength of the oxidized wet beaded carbon black pellets having a diameter of 1.0 to 1.4 mm may be 4 to 80 cN, preferably 5 to 40 cN, more preferably 10 to 30 cN. The average pellet crushing strength of the oxidized wet beaded carbon black pellets having a diameter of 1.4 to 1.7 mm may be 3 to 80 cN, preferably 4 to 40 cN, more preferably 5 to 30 cN.

[0057] Pellet crush strength, for example average pellet crush strength, can be measured according to ASTM D5230-19.

[0058] It is particularly desirable that the average pellet crushing strength of pellets having a diameter of 0.71 to 1.0 mm is 4 to 80 cN, preferably 5 to 40 cN, more preferably 10 to 30 cN, that the average pellet crushing strength of pellets having a diameter of 1.0 to 1.4 mm is 4 to 80 cN, preferably 5 to 40 cN, more preferably 10 to 30 cN, and that the average pellet crushing strength of pellets having a diameter of 1.4 to 1.7 mm is 3 to 80 cN, preferably 4 to 40 cN, more preferably 5 to 30 cN.

[0059] It is particularly desirable that the average pellet crushing strength of the five hardest pellets having a diameter of 0.71 to 1.0 mm is 10 to 110 cN, preferably 12 to 80 cN, more preferably 15 to 60 cN, and most preferably 17 to 50 cN. The pellet crushing strength of the hardest pellets having a diameter of 0.71 to 1.0 mm should be 10 to 110 cN, preferably 12 to 80 cN, more preferably 15 to 60 cN, and most preferably 17 to 50 cN. The average pellet crushing strength of the five hardest pellets having a diameter of 1.0 to 1.4 mm should be 10 to 110 cN, preferably 12 to 80 cN, more preferably 15 to 60 cN, and most preferably 17 to 50 cN. The pellet crushing strength of the hardest pellets with a diameter of 1.0-1.4 mm should be 10-110 cN, preferably 12-80 cN, more preferably 15-60 cN, and most preferably 17-50 cN.

[0060] The fines content of the oxidized wet beaded carbon black may be 0.1-50%, preferably 1-10%, more preferably 1-5%. The fines content can be measured according to ASTM D1508-02. Low fines content is an indicator to avoid the destruction of beads / pellets during the oxidation process.

[0061] Pellet attrition should be less than 6.5%, preferably 0.1-5%, more preferably 0.2-3%, and most preferably 0.5-2%. Pellet attrition can be measured according to ASTM D1508-02. Low pellet attrition is desirable so that bead conveying and mixing is improved. Additionally, low pellet attrition prevents pellet breakage during conveying or handling.

[0062] A screw conveyor for producing oxidized wet beaded carbon black and used in the method and control device of the present invention typically includes a reaction chamber and at least one ozone inlet for supplying ozone to the reaction chamber.

[0063] The screw conveyor is typically a cylinder containing a "helical blade" coiled around a shaft. The screw conveyor is further modified to allow for oxidation of the wet beaded carbon black. Thus, the screw conveyor includes at least one ozone inlet for supplying ozone to the chamber of the screw conveyor. In this manner, the chamber of the screw conveyor is a reaction chamber where an oxidizing agent, such as ozone, can oxidize the wet beaded carbon black.

[0064] Thus, the screw conveyor can contain ozone in the reaction chamber, preferably 0.1-80% by weight, more preferably 0.5-20% by weight, most preferably 1-10% by weight of the gas present in the reaction chamber is ozone. The ozone inlet further comprises means for controlling and / or measuring the supply of ozone to the reaction chamber to adjust the concentration of ozone in the reaction chamber. Furthermore, the reaction chamber can contain wet beaded carbon black and / or oxidized wet beaded carbon black. In short, the reaction chamber should contain wet beaded carbon black and oxidized wet beaded carbon black as well as ozone, preferably in the amounts / concentrations mentioned above. The ozone inlet is preferably located at the bottom of the vessel of the screw conveyor.

[0065] The screw of the screw conveyor (conveyor screw) can be a conventional helical screw blade. The screw of the screw conveyor has a screw thread (or a helical screw blade), and the screw thread can have 2 to 100 turns, preferably 5 to 50 turns. The screw thread can have a pitch of 0.1 to 5, preferably a continuous or constant increasing / decreasing pitch.

[0066] The screw conveyor may include at least one temperature control unit for cooling or heating the reaction chamber. During the oxidation of the wet beaded carbon black, the temperature may increase. The temperature of the reaction chamber may be controlled by the temperature control unit to avoid the risk of losing volatiles (which would reduce the degree of oxidation). However, in processes that result in less oxidized carbon black, it may be beneficial to transfer additional heat to the reaction chamber for the oxidation step. The temperature control unit is preferably attached to the outer surface of the reaction chamber or barrel.

[0067] The screw of the screw conveyor (conveyor screw) may be a conventional helical screw blade. The screw of the screw conveyor has a screw thread (or a helical screw blade), and the screw thread may have 2 to 100 turns, preferably 5 to 50 turns. The screw thread may have a continuous or a constant increasing / decreasing pitch. Generally, the screw comprises a shaft and a helical conveyor blade thereon. However, it is also possible that the screw is a shaftless helical conveyor blade. Thus, the blade may be directly driven by a motor. The screw conveyor may comprise a helical conveyor blade. The screw generally has at least one screw flight extending radially and helically from and along the shaft.

[0068] The screw may be configured at least partially as a flight, preferably at least partially as a single flight, more preferably at least partially as a double flight, and the screw includes at least one second helical conveyor blade (second flight), and when the screw is configured at least partially as a double flight ribbon, it further includes at least one first helical conveyor blade (first flight).

[0069] The screw conveyor or helical conveyor blade may include at least one first helical conveyor blade and / or at least one second helical conveyor blade. The first and second helical conveyor blades may be arranged in sequence, thus forming a single thread. It may also be desirable for the first and second helical conveyor blades to form a double-start thread (or a double-start thread, or a double flight). For example, the first and second helical conveyor blades may form a high-low thread, the first helical conveyor blade being a low thread and the second helical conveyor blade being a high thread. Each revolution of the first conveyor blade may extend over at least a portion of the length of the shaft between each subsequent revolution of the second conveyor blade. If a double-start thread is present, it is not necessary for both threads to start at the same time.

[0070] The second spiral conveyor blade may extend over at least a portion of the length of the shaft, with a radial distance to the shaft, thereby forming a circumferential clearance between the shaft and the second spiral conveyor blade. A spiral conveyor blade having such a clearance is commonly referred to as a flight ribbon. Thus, the screw may be configured at least partially as a flight ribbon, preferably at least partially as a single flight ribbon, more preferably at least partially as a double flight ribbon.

[0071] The screw may be configured at least partially as a flighted ribbon, preferably at least partially as a single-flighted ribbon, more preferably at least partially as a double-flighted ribbon, and the screw includes at least one second helical conveyor blade (second flight), and when the screw is configured at least partially as a double-flighted ribbon, further includes at least one first helical conveyor blade (first flight).

[0072] The screw may be configured as a flight ribbon, preferably a single flight ribbon, more preferably a double flight, where one flight at least partially comprises the flight ribbon, and the screw comprises at least one second helical conveyor blade (second flight), and when the screw is configured as a double ribbon, it further comprises at least one first helical conveyor blade (first flight), where the at least one second helical conveyor blade (second flight) is at least partially configured as a flight ribbon.

[0073] The screw may be configured as a double flight, the screw comprising at least one second helical conveyor blade (second flight) and at least one first helical conveyor blade (first flight), the at least one second helical conveyor blade (second flight) being particularly preferably configured at least partially as a flight ribbon (preferably a second section), the flight ribbon being preferably adjacent to the ozone inlet.

[0074] It is also preferred that the screw can be configured as one flight, the screw includes at least one second spiral conveyor blade (second flight), the at least one second spiral conveyor blade (second flight) is at least partially configured as a flight ribbon (preferably as a second section), preferably the at least one second spiral conveyor blade (second flight) has three sections, the first section being a flight directly and continuously attached to the shaft, the second section being a flight ribbon, and the third section being a flight directly and continuously attached to the shaft. It is preferred that the flight ribbon is adjacent to the ozone inlet. The second section should be located between the first section and the second section.

[0075] It is particularly preferred that the screw can be configured as a double flight, the screw comprising at least one second spiral conveyor blade (second flight) and at least one first spiral conveyor blade (first flight), the at least one second spiral conveyor blade (second flight) being at least partially configured as a flight ribbon (preferably as a second section), preferably the at least one second spiral conveyor blade (second flight) having three sections, the first section being a flight directly and continuously attached to the shaft, the second section being a flight ribbon, the third section being a flight directly and continuously attached to the shaft, preferably the at least one first spiral conveyor blade (first flight) being a flight directly and continuously attached to the shaft. It is preferred that the flight ribbon is adjacent to the ozone inlet. The second section should be located between the first section and the second section.

[0076] The clearance between the shaft and the helical conveyor blade in a conventional screw conveyor has the drawback of reducing the ability to transport material. In other words, the main purpose of a conventional screw conveyor is the transportation of material, for example to overcome an incline. However, the screw conveyor according to the present invention is not only used to transport material, but also to oxidize the feed material. Such blades with clearance between the shaft and the helical conveyor blade can be beneficially used for oxidation. The oxidizing agent can be better distributed through the reaction chamber and the wet beaded carbon black can be mixed uniformly. The uniform mixing during oxidation allows for improved and uniform oxidation of the wet beaded carbon black.

[0077] It is particularly preferred that the second spiral conveyor blade, having a radial distance to the shaft thereby forming a circumferential clearance between the shaft and the second spiral conveyor blade, extends over at least a portion of the length of the shaft in which the ozone inlet is located.

[0078] The second spiral conveyor blade may include a first section including a spiral conveyor blade attached directly to the shaft, and a second section including a spiral conveyor blade extending over at least a portion of the length of the shaft (preferably where the ozone inlet is located) with a radial distance to the shaft, thereby forming a circumferential clearance between the shaft and the second spiral conveyor blade. Furthermore, the second spiral conveyor blade desirably includes a first section including a spiral conveyor blade attached directly to the shaft, a second section including a spiral conveyor blade extending over at least a portion of the length of the shaft (preferably where the ozone inlet is located) with a radial distance to the shaft, thereby forming a circumferential clearance between the shaft and the second spiral conveyor blade, and a third section including a spiral conveyor blade attached directly to the shaft. The second spiral conveyor blade preferably includes sections in the following order: a first section, a second section and a third section. The first helical conveyor blade may form a second thread of the screw, the diameter (or outer diameter) of the first helical conveyor blade being smaller than the diameter (or outer diameter) of the second helical conveyor blade.

[0079] The second conveyor blade can be attached to the shaft over at least a part of the length of the shaft via spacer bars extending radially from the shaft, preferably via three or more bars. In particular, if the second conveyor blade has a radial distance to the shaft, thereby forming a circumferential clearance between the shaft and the second spiral conveyor blade, it can be attached to the shaft over at least a part of the length of the shaft via spacer bars extending radially from the shaft, preferably via three or more bars. This means that the part of the second conveyor blade having said clearance should be attached to the shaft over at least a part of the length of the shaft via spacer bars extending radially from the shaft, preferably via three or more bars.

[0080] The radial distance to the shaft forming a circumferential clearance between the shaft and the second spiral conveyor blade should be between 10 and 200 mm, preferably between 20 and 150 mm, more preferably between 30 and 100 mm, even more preferably between 40 and 80 mm, and most preferably between 45 and 70 mm.

[0081] In conventional screw conveyors, the creation of a circumferential clearance between the shaft and the helical conveyor blades due to the radial distance to the shaft is a drawback in that it reduces the ability to transport material. In other words, the main purpose of conventional screw conveyors is the transportation of material, for example overcoming inclines. However, the screw conveyor according to the present invention is not only used to transport material, but also to oxidize the feed material. Such blades with clearance can be beneficially used for oxidation. The oxidizing agent can be better distributed through the reaction chamber and the wet beaded carbon black can be mixed uniformly. The uniform mixing during oxidation allows for an improved and uniform oxidation of the wet beaded carbon black.

[0082] The first conveyor blade has a first outer diameter and the second conveyor blade has a second outer diameter, preferably the first and second outer diameters being different from each other. In particular, the first outer diameter is smaller than the second outer diameter. The spacing (lead) of the second conveyor blade over at least a portion of the length of the shaft should be smaller than the spacing (lead) of the first conveyor blade.

[0083] The screw conveyor can include a drive and a driven screw extending into a barrel forming a reaction chamber, the screw including a shaft and at least one first helical conveyor blade. The drive should be configured to drive the driven screw.

[0084] Typically, the screw of the screw conveyor comprises a shaft and at least one first helical conveyor blade. Alternatively or additionally, the screw of the screw conveyor comprises a shaft and at least one second helical conveyor blade.

[0085] The screw of the screw conveyor and / or reaction chamber can have a length of 0.1-100 m, e.g., 1-20 m, 5-15 m, 2-4 m, 10-90 m, or 20-80 m. The volume of the reaction chamber can be 1-10000 L, e.g., 10-1000 L, 20-100 L, 2-50 L, 100-9000 L, or 500-5000 L. The volume of the reaction chamber can be selected as required for the process. A higher input of wet beaded carbon black feed requires a larger reaction chamber. The screw conveyor can include a drive and a driven screw that extends into a barrel that forms the reaction chamber. The screw conveyor typically includes an inlet for the wet beaded carbon black to the reaction chamber. Similarly, the screw conveyor typically includes an outlet for the produced oxidized wet beaded carbon black, the outlet being located on the opposite side of the reaction chamber relative to the inlet. The inlet is located at the top of the screw conveyor and the outlet is located at the bottom of the screw conveyor.

[0086] The diameter of the screw may be 50-300 mm, preferably 60-250 mm, more preferably 70-200 mm, even more preferably 80-150 mm, most preferably 90-130 mm. The diameter of the at least one first and / or at least one second spiral conveyor blade may be 50-1000 mm, preferably 100-800 mm, more preferably 150-700 mm, even more preferably 200-600 mm, most preferably 250-400 mm. The diameter of the at least one first spiral conveyor blade may be 25-500 mm, preferably 50-400 mm, more preferably 75-350 mm, even more preferably 100-300 mm, most preferably 150-300 mm. The inner diameter of the barrel may be 50-3000 mm, for example 100-800 mm, 150-700 mm, 200-600 mm, 250-400 mm, 100-2000 mm, or 150-1000 mm, preferably the inner diameter of the barrel is larger than the diameter of the at least one first and / or at least one second spiral conveyor blade. The inner diameter of the at least one second spiral conveyor blade may be 40-900 mm, preferably 80-750 mm, more preferably 130-650 mm, even more preferably 180-550 mm, most preferably 230-350 mm. The outer diameter of the at least one second spiral conveyor blade should be between 50 and 1000 mm, preferably between 100 and 800 mm, more preferably between 150 and 700 mm, even more preferably between 200 and 600 mm, and most preferably between 250 and 400 mm.

[0087] In general, the size of each of the components of the screw conveyor should be selected relative to the size of the screw conveyor. Large screw conveyors usually include larger components and larger dimensions of the components. Therefore, the size and dimensions of a particular component or part of the screw conveyor usually match.

[0088] The gap between the spiral conveyor blade and the inner surface of the reactor chamber can be from 0 mm (or more than 0 mm) to 200 mm, preferably from 1 mm to 100 mm, more preferably from 2 mm to 80 mm, even more preferably from 5 to 50 mm, and most preferably from 10 to 40 mm.

[0089] The at least one first and / or at least one second spiral conveyor blade may include at least one turner attached to a surface opposite to the conveying direction. The turner should be capable of lifting a portion of the wet beaded carbon black material so that mixing of the material is improved. This allows for uniform mixing of the material so that oxidation is promoted.

[0090] The at least one first and / or at least one second spiral conveyor blade may include at least one first turner and at least one second turner. The at least one first and at least one second turner may be alternately attached to the at least one first and / or at least one second spiral conveyor blade. The angle of the at least one first turner must be greater than the angle of the at least one second turner, the turner extending at an angle to the tangent of the circumference of the second conveyor blade (as shown in FIG. 8). The angle of the at least one first turner may be 30-100°, preferably 35-90°, more preferably 40-80°, even more preferably 50-70°, and most preferably 55-65°. The angle of the at least one second turner is between 10 and 60°, preferably between 15 and 55°, more preferably between 20 and 50°, even more preferably between 25 and 45°, and most preferably between 35 and 45°, and the turner extends at an angle to a tangent to the circumference of the second conveyor blade.

[0091] The present invention will now be described with reference to the accompanying drawings, which do not limit the scope and area of ​​the present invention. The description provided is purely for the purposes of example and illustration. However, certain features illustrated in the drawings may be used to further limit the scope of the present invention and the claims.

[0092] FIG. 1 relates to a method for producing oxidized wet-beaded carbon black (202). First, carbon black is provided (101), preferably as a powder. As mentioned above, the carbon black powder is preferably furnace black. However, any type of carbon black material can be used according to the invention, including mixtures of carbon black materials. In a second step, the carbon black is wet-beaded. Wet-beading can include treating the carbon black powder with water and optionally a binder. The mixture is subsequently beaded and dried to obtain the wet-beaded carbon black (102). The beads are then subjected to an oxidation step (103) to obtain the oxidized wet-beaded carbon black (202). The oxidation step is preferably carried out in a screw conveyor (200, 300) according to the invention. However, the specific means for oxidation is not limited to a screw conveyor. Preferably, ozone is used as the oxidizing agent.

[0093] Referring to FIG. 2, an inner portion of a screw conveyor (200) according to the present invention is shown. The screw conveyor (200) comprises at least one first spiral conveyor blade (214, 502) mounted on a shaft (213) connected to an electric motor (215) that drives the screw. Alternatively, the spiral conveyor blade shown in FIG. 2 is at least one second spiral conveyor blade (501). The screw conveyor (200) further comprises a barrel (211) that defines a reaction chamber (218) or provides a barrier that defines the reaction chamber (218). The screw conveyor (200) comprises an inlet (210) for the wet beaded carbon black (201) and an outlet (212) for the produced oxidized wet beaded carbon black (202). At the bottom of the screw conveyor (200) are attached several ozone inlets (216) which feed ozone (217) into the reaction chamber (218). The screw includes at least one first spiral conveyor blade (214) to convey the feed material in a direction from the inlet towards the outlet. If there is a second spiral conveyor blade (501) extending over at least a portion of the length of the shaft and having a radial distance to the shaft (213) thereby forming a circumferential clearance (503) between the shaft (213) and the second spiral conveyor blade (501), it is desirable that the clearance (i.e. the radial distance to the shaft (213) which forms the circumferential clearance (503) between the shaft (213) and the second spiral conveyor blade (501)) is located over the length of the portion of the shaft where the ozone inlet is located. The longitudinal direction of the screw (220) is shown in FIG.

[0094] With reference to FIG. 3, an outer portion of a screw conveyor (300) according to the invention is shown. In this view, three temperature control units (301) are visible, which are attached to the outer wall of the screw conveyor (300), i.e., to the outer wall of the barrel (211). The temperature control units extend on opposite sides of the screw conveyor (300), which are not shown in this view. Each temperature control unit (301) includes an inlet (302) for a fluid, such as water, and an outlet (303) for a fluid, such as water. The inlets (301) and outlets (302) can be interchanged. Furthermore, the barriers (304) are shown as dashed lines indicating the flow path of the fluid. Thus, each barrier has at least one opening to define a flow path so that the fluid can be transported from the inlet (302) to the outlet (303). Some openings are not shown in the view, since they are on the opposite side of the temperature control units (301).

[0095] FIG. 4 shows a section of a screw (400) including at least one first helical conveyor blade (214, 502) attached to a shaft (213). In this figure, a screw configured as a single flight (at least partially) is shown. The at least one first helical conveyor blade (214, 502) is attached directly to the shaft (213) without a radial distance to the shaft (213) and thus without forming a circumferential clearance (503) between the shaft (213) and the first helical conveyor blade (214, 502). Alternatively, the helical conveyor blade shown in FIG. 2 is at least one second helical conveyor blade (501). The spacing of the first conveyor blades (214, 502) is shown in the figure. The spacing of the first conveyor blades is the lead. The spacing of a particular conveyor blade or the lead of a particular conveyor blade is the distance along the axis of the screw that is covered by one complete revolution of the conveyor blade. If the screw contains only one conveyor blade, the lead and pitch are the same (single start thread). In Figure 4, the flights are attached directly and continuously to the shaft (no clearance, not a flight ribbon).

[0096] Figure 5 shows a section of a screw (500) comprising a shaft (213), at least one first helical conveyor blade (502) and at least one second helical conveyor blade (501), which second helical conveyor blade extends over at least a partial length of the shaft, with a radial distance to the shaft (213), thereby forming a circumferential clearance (503) between the shaft (213) and the second helical conveyor blade (501). The screw is therefore designed as a double-thread (or double-start thread), the first helical conveyor (502) being a low thread and the second helical conveyor being a high thread (501). This means that each revolution of the first conveyor blades (214, 502) extends between each subsequent revolution of the second conveyor blade (501) over at least a partial length of the shaft. This configuration is preferably present where the ozone inlet is located. Thus, the described screw (500) is preferably located in the central part of the screw, where the inlet for ozone (216) is preferably located. Thus, the ozone (217) provided through the inlet (216) can be easily distributed in the reaction chamber (218) and an improved uniform oxidation is achieved. It should be noted that the at least one second helical conveyor blade (501) extends over at least a part of the length of the shaft (213) while having a radial distance to the shaft (213), thereby forming a circumferential clearance (503) between the shaft (213) and the second helical conveyor blade (501), and can be attached to the screw via a bar (spacer bar) not shown in the figure. The bar (spacer bar) can support the structure. However, any conceivable means for attaching the at least one second helical conveyor blade (501) to the screw can be used. The spacing (504) or lead (504) of the at least one first helical conveyor blade (502) is shown in Figure 5. The spacing (505) or lead (505) of the at least one second helical conveyor blade (501) is shown in Figure 5.In this figure, the screw is shown configured as a double flight (at least partially) with a ribbon flight, which is at least one second helical conveyor (501).

[0097] Referring to Fig. 6, a screw (600) with different sections of helical conveyor blades (601, 602, 603) is shown. In this configuration, the screw includes a shaft (213), at least one first helical conveyor blade (502) and at least one second helical conveyor blade (501), which has a radial distance to the shaft (213), thereby extending over at least a portion of the length of the shaft while forming a circumferential clearance (503) between the shaft (213) and the second helical conveyor blade (501). The screw is designed as a double-thread (or double-start thread), with the first helical conveyor (502) being a low thread and the second helical conveyor being a high thread (501). Thus, the second spiral conveyor blade (501) extends only partially over the length of the shaft while having a radial distance to the shaft (213), thereby forming a circumferential clearance (503) between the shaft (213) and the second spiral conveyor blade (501). This portion is shown as section (602). Thus, the second spiral conveyor blade (501) in sections (601) and (603) is directly attached to the shaft (213). A smooth transition is generally made from the section of the second spiral conveyor blade (501) to which the shaft (213) is directly connected, to the section that extends over at least a portion of the length of the shaft while having a radial distance to the shaft (213), thereby forming a circumferential clearance (503) between the shaft (213) and the second spiral conveyor blade (501).

[0098] 7 and 8 show a cross section of a screw including a shaft (213), at least one first helical conveyor blade (502), at least one second helical conveyor blade (501) and further turners (702, 703), the second helical conveyor blade extending over at least a portion of the length of the shaft with a radial distance to the shaft (213) thereby forming a circumferential clearance (503) between the shaft (213) and the second helical conveyor blade (501). The at least one second helical conveyor blade (501) extending over at least a portion of the length of the shaft with a radial distance to the shaft (213) thereby forming a circumferential clearance (503) between the shaft (213) and the second helical conveyor blade (501) is attached to the screw (213) via a spacer bar (701). Reference numeral 502 indicates that at least one first spiral conveyor blade (502) has a smaller diameter. In Fig. 8, the respective diameters and clearances (503) of the respective spiral conveyor blades are shown. The inner diameter (804) of at least one second spiral conveyor blade (501) extending over at least a portion of the length of the shaft while having a radial distance to the shaft (213) thereby forming a circumferential clearance (503) between the shaft (213) and the second spiral conveyor blade (501) simultaneously defines the clearance (503) between the second spiral conveyor blade (501) and the shaft (213). It should be noted that the diameters mentioned in this specification refer to the diameters of the spiral conveyor blades, taking into account a cross section, for example as shown in Fig. 7.Further shown in Figure 8 is the outer diameter (803) of the at least one second spiral conveyor blade (501) extending over at least a portion of the length of the shaft (213) while having a radial distance to the shaft (213) and thereby forming a circumferential clearance (503) between the shaft (213) and the second spiral conveyor blade (501), the distance (807) between the at least one first spiral conveyor blade (502) and the at least one second spiral conveyor blade (501), the diameter (806) of the at least one first spiral conveyor blade (502), and the distance (805) between the inner and outer diameters of the at least one second spiral conveyor blade (501). As can be seen in Figure 8, the turners (702, 703) are attached to the at least one second spiral conveyor blade (501) at specific angles (801, 802). Each angle is such that the turner extends at an angle relative to a tangent to the circumference of the second conveyor blade, as shown in particular in Figure 8. As mentioned above, the turner (702, 703) may also be attached to at least one of the first helical conveyor blades (214, 502).

[0099] Figure 9 shows an oxidized wet-beaded carbon black prepared according to the present invention. As can be seen from the image, it is possible to oxidize the wet-beaded carbon black without destroying the beads.

[0100] FIG. 10 is directed to the control device and method (900) of the present invention. A user can select the desired oxidized wet beaded carbon black to be produced (901). The three lookup tables represent the first lookup table for different products shown as Product 1, Product 2 and Product 3. Set motor current I set (t) and the set rotation speed n set (t) is received by the method or control device of the present invention (902). The current sensor (911) detects the set rotation speed n setThe primary controller (910) is then used to detect the motor current I(t) used by the electric motor (215) to apply and / or maintain the set motor current I(t). set (t) is compared with the motor current I(t), and the difference between the currents (i.e., the result ΔI or difference current ΔI) is used to adjust the set rotation speed n(t) to n(t). The new or adjusted rotation speed n(t) is then transmitted to the electric motor (215) of the screw conveyor (200). Based on the adjusted rotation speed n(t), a new or corrected second set motor current is received from the first lookup table (920) for the desired product to be manufactured. In addition, preferably, a set ozone flow rate q is obtained from the second lookup table (921) based on the rotation speed n(t) (i.e., the adjusted rotation speed n(t)). ozone,set Set ozone flow rate q by receiving (n,t) ozone,set (n,t) is generated from the rotational speed n(t) (i.e., the adjusted rotational speed n(t)). EXAMPLES

[0101] Example 1: Preparation of oxidized wet-beaded carbon black according to the present invention The carbon black powder used to prepare the oxidized wet beaded carbon black in Examples AI is N234.

[0102] In Examples AH, the carbon black powder is converted into wet beads by applying water to the carbon black powder to convert the wet carbon black powder into beads, and then drying the resulting wet-beaded carbon black.

[0103] The wet beaded carbon black is then subjected to a screw conveyor for oxidation. Ozone is fed into the reaction chamber of the screw conveyor to oxidize the wet beaded carbon black. The setup and results of the production of oxidized wet beaded carbon black are shown in Table 1. The ozone flow rate indicates the target ozone flow rate in the reaction chamber. The reaction chamber of the screw conveyor is cooled with water.

[0104] In Comparative Example I (Comparative Example I), the carbon black powder is first oxidized and then dry beaded to avoid devolatilization of the carbon black beads.

[0105] Table 1: Preparation of oxidized wet-beaded carbon black. [Table 1] 1 Pellet crush strength is measured according to ASTM D5230-19. 2 Fines content is measured according to ASTM D1508-02. 3 Volatiles are measured at 950° C. for 7 minutes as described below. 4 BET surface area is measured according to ASTM D6556-17. 5 STSA surface area is measured according to ASTM D6556-17. 6 Iodine adsorption is measured according to ASTM D1510-17. 7 Pellet attrition is measured according to ASTM D1508-02. 8 The pH value is measured according to ASTM D1512-15b, Test Method B - Sonic Slurry. 9 Oil absorption is measured according to ASTM D2414-18. 10 Weight ratio of carbon black to ozone.

[0106] The volatile content at 950 °C was measured using a thermogravimetric analyzer (TGA-701) manufactured by Fa.LECO Instruments according to the following procedure. The sample pan was dried at 650 °C for 30 min. The carbon black material was stored in a desiccator equipped with a desiccant prior to measurement. The baked-out sample pan was loaded into the instrument, tared, and filled with 0.5 g to 10 g of carbon black material. The oven of the TGA instrument loaded with the sample-filled pan was then gradually heated to 105 °C by automated software control to dry the sample until a constant mass was achieved. The pan was then closed with a lid, and the oven was purged with nitrogen (99.9 vol.% grade) and heated to 950 °C. The oven temperature was maintained at 950 °C for 7 min. The volatile content at 950 °C was calculated using the following formula:

number

[0107] The produced oxidized wet-beaded carbon black has a remarkable pellet crush strength compared to the beads obtained in Comparative Example I. This indicated that the beads were not destroyed during the oxidation treatment in the screw conveyor. The pellet crush strength is particularly high by using a low screw rotation speed, such as 0.5 rpm instead of 3 rpm. Meanwhile, by using a higher screw rotation speed, the fines content is lower. The BET, STSA and CTAB surface areas of the produced oxidized wet-beaded carbon black are larger compared to the palletized carbon black according to Comparative Example I. Furthermore, the pellet wear and OAN are improved compared to the palletized carbon black according to Comparative Example I. Figure 11 shows the oxidized wet-beaded carbon black produced according to Example A.

[0108] The data provided in Examples A to H are based on the set rotation speed n set (t) and the set motor current I set (t), and the set rotation speed n for the production of the desired oxidized wet beaded carbon black. set The required set ozone flow rate q (t) ozone,setcan be used in a lookup table to obtain (n,t) and the carbon black beads will not be crushed. [Explanation of symbols]

[0109] 200 Screw Conveyor 201 Wet bead carbon black 202 Oxidized wet bead carbon black 210 Entrance 211 barrels 212 Exit 213 Shaft 214 First spiral conveyor blade 215 Electric Motor 216 Ozone inlet 217 Ozone 218 Reaction Chamber 501 Second Spiral Conveyor Blade 502 First spiral conveyor blade 503 Circumferential clearance 504 First spiral conveyor blade spacing 505 Second spiral conveyor blade spacing 702, 703 Turner 801, 802 Turner's angle

Claims

1. The rotation speed n(t) of the screw conveyor (200, 300) and the ozone flow rate q for producing the oxidized wet beaded carbon black (202) ｏｚｏｎｅ Methods for controlling (n, t): Here, the screw conveyor (200, 300) includes an electric motor (215) that drives a conveyor screw (213), which conveys the wet beaded carbon black (201) from a material inlet (210) toward a material outlet (202) while passing through a reaction chamber (218) containing ozone, and the reaction chamber (218) further includes an ozone flow rate q ｏｚｏｎｅ and at least one ozone inlet (216) configured to adapt (n, t), and the method includes current regulating power control of the motor according to a predetermined correlation of set points for a particular carbon black product.

2. The method of claim 1, wherein the method comprises the steps of: (A) From the predetermined correlation, a set rotation speed n is determined for the specific oxidized wet beaded carbon black (202) to be produced. ｓｅｔ (t) and the set ozone flow rate q ｏｚｏｎｅ，ｓｅｔ Determining and setting (n, t); (B) detecting the actual motor current I(t) of the electric motor (215) during operation; (C) Computing the actual motor current I(t) relative to a first predetermined set motor current I from the predetermined correlation of set points. ｓｅｔ comparing with (t); (D) Based on the result of the comparison (ΔI), the primary control device (910) is used to set the rotation speed n ｓｅｔ (t) to n(t), (E) determining a corrected second set motor current and a corrected set ozone flow rate based on the adjusted rotational speed; (F) Set ozone flow rate q from rotation speed n(t) ｏｚｏｎｅ，ｓｅｔ (n, t), and (G) Adapting the ozone flow rate into the reaction chamber accordingly.

3. 3. The method of claim 2, wherein steps (B) through (G) are repeated in the order listed.

4. Steps (A) and / or (E) may include determining n for at least one specific product. ｓｅｔ (t) and I ｓｅｔ 4. The method of claim 2 or 3, comprising retrieving data from at least a first look-up table containing data representing a plurality of correlation values ​​of (t).

5. Steps (A) and / or (F) include n(t) and q ｏｚｏｎｅ，ｓｅｔ 4. The method of claim 2 or 3, further comprising retrieving data from a second lookup table containing data representing a plurality of (n,t) correlation values.

6. Step (D) is the rotation speed n ｓｅｔ 4. The method of claim 2 or 3, comprising decreasing (t) by predetermined increments.

7. Step (D) is the rotation speed n ｓｅｔ 4. The method of claim 2 or 3, comprising intermittently decreasing (t) for a predetermined time.

8. 4. The method of claim 2 or 3, wherein the rotational speed of the conveyor screw is adjusted in response to detecting the actual motor current based on a predetermined correlation between motor current and rotational speed for a particular carbon black product.

9. 10. The method of claim 8, further comprising adjusting the ozone flow rate in response to the adjusted rotation speed based on a predetermined correlation between rotation speed and ozone flow rate for a particular carbon black product.

10. The rotation speed n(t) of the screw conveyor (200, 300) and the ozone flow rate q for producing the oxidized wet beaded carbon black (202) ｏｚｏｎｅ Control device (900) for controlling (n, t): Here, the screw conveyor (200, 300) includes an electric motor (215) that drives a conveyor screw (213), which conveys the wet beaded carbon black (201) from a material inlet (210) toward a material outlet (202) while passing through a reaction chamber (218) containing ozone, and the reaction chamber (218) further includes an ozone flow rate q ｏｚｏｎｅ (n, t) and the controller (900) is configured to perform current regulating power control of the motor in response to a predetermined correlation of set points for a particular carbon black product.

11. A control device according to claim 10, configured to carry out the method of claim 1.

12. 12. A control system according to claim 10 or 11, comprising a primary control system, means for detecting and / or monitoring actual motor current during operation, means for detecting and / or monitoring and / or controlling rotational speed, and data storage means including a database for product specific power settings for the screw conveyor.

13. n for at least one specific product ｓｅｔ (t) and I ｓｅｔ 12. A control device (900) according to claim 10 or 11, comprising data storage means for storing at least a first look-up table containing data representing a plurality of correlation values ​​of (t).

14. The data storage means stores n(t) and q ｏｚｏｎｅ，ｓｅｔ 12. The control device (900) of claim 10 or 11, comprising a second look-up table containing data representing a plurality of correlation values ​​for (n, t).

15. Set ozone flow rate q ｏｚｏｎｅ，ｓｅｔ Based on (n, t), the flow rate q ｏｚｏｎｅ The control device (900) of claim 10 or 11, comprising a flow controller configured to control (n, t).

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