RU2106375C1 - Method for producing carbon granulated material - Google Patents

Abstract

FIELD: metallurgy; metal carbonization, production of carbon carriers, catalysts and sorbents. SUBSTANCE: carbon black pellets are classified into fractions sizing 0.2-1, 1-3 and 3-6 mm, and pyrolytic carbon is precipitated on them in moving layer in rotary horizontal reactor. Pyrolytic carbon is formed in thermal decomposition of gaseous or vaporous hydrocarbons at 900-1030, 80-900 and 750-800 C for each above-indicated fractions, respectively. Apparent density of granulated material is 1.56-1.63 g/cu.cm and process output is 8.8-57.5 kg/h. EFFECT: higher efficiency.

Description

 The invention relates to the production of carbon materials, mainly to methods for producing granular carbon material by thermal conversion of hydrocarbons and can be used to produce carbon material, the use of which is advisable in metallurgy as a carburizer of metals or a reducing agent, as well as in the production of carbon carriers of catalysts and sorbents.

 The aim of the invention is to increase the apparent density of the granular material and process performance.

This provides a method for producing carbon granular material by heating a moving layer of granular soot in a horizontal rotating reactor by supplying gaseous or vaporous hydrocarbons to the moving layer, followed by their thermal decomposition at 750 - 1200 ^o C and the deposition of pyrocarbon on soot. In this case, the soot granules before heating are classified into fractions of size 0.2 - 1 mm, 1 - 3 mm, 3 - 6 mm and pyrocarbon is deposited on each of these fractions of soot at 900 - 1030, 800 - 900, 750 - 800 ^o C respectively. The classification of carbon black granules before heating in a rotating horizontal reactor allows you to select the optimal process temperature, providing the maximum carbonization rate for a given granule size and ultimately increase the uniformity of the target product and the apparent density.

 The classification of carbon black granules into 3 groups by size is determined by both the areas of application of the carbon material and the optimization of process parameters in a given temperature range.

 For example, the carbon material used for alloying steel during out-of-furnace treatment in a vacuum should have an optimal granule size of 3–6 mm, and in the production of a catalyst support 0.2–1.0 mm (for suspension processes) and 1–3 mm (for processes in the stationary layer). It is technically difficult to obtain carbon material with a granule size of less than 0.2 mm, since in the process of carburization they are removed from the reactor with a stream of exhaust gases.

 Obtaining the initial carbon black soot with a granule size above 6 mm is also technically difficult, since in practice the size of the carbon black granules usually does not exceed 6 mm.

In the industrial process, the isothermal conditions are not met and a temperature gradient exists up to a layer height (up to 100 ^o C) due to the segregation of granules in size and the structural design of the reactor. As a result of segregation, the loaded mass of granular soot (0.2 - 6.0 mm) is divided into several layers that are in different temperature conditions. In this case, uniform mixing of the substrate layer does not occur. Granules of large sizes (fraction 3.0 - 6.0 mm) form the upper layer of the mixed mass and have the highest temperature, granules of 1.0 - 3.0 mm size occupy the position of a layer between small 0.2 - 1.0 mm and large granules and have a lower temperature due to the low thermal conductivity of soot. The smallest granules (0.2 - 1.0) remain at the bottom of the reactor and are in contact only with the lining of the reactor. In addition, the temperature gradient is enhanced by introducing a raw gas with a relatively low temperature (60 - 80 ^o C) through a gas manifold located in the lower part of the substrate layer. In this case, small granules are in the least favorable temperature conditions. Hence, when implementing the process, the rates of carburization of the fractions are different, and for a given duration of the process, each fraction has apparent density values that are different from each other. In addition, with increasing temperature for larger granules, the effect of mass transfer on the depth of penetration of the reaction increases. As a result, the product obtained by a known method is heterogeneous.

 In the method according to the invention, when carburizing narrower fractions (after classification) under optimal temperature conditions, the required uniformity of the finished product and higher process productivity are provided.

Example 1. Granular soot (P 514) is classified into fractions of 0.2 - 1.0 mm, 1 - 3 mm, 3 - 6 mm. 160 kg of granular soot fraction 0.2 - 1.0 mm are loaded into a reactor with an inner diameter of 1.2 m. The reactor is rotated at a speed of 1 rpm. A fuel burner is used to warm up and maintain the set temperature. At a temperature of 730 ^° C., a propane-butane mixture is supplied at a speed of 9 nm ³ / h through a water-cooled collector located in the soot layer. When a constant value is reached with respect to the gain (complete carbonization of the outer surface), after 69 hours from the moment the propane-butane mixture is supplied, the process ends.

 After unloading from the reactor and cooling the material, the apparent density of the granules of the fraction 0.2 - 1.0 mm is determined. It amounted to 1.63 (table. 1).

Examples 2 to 6 are similar to example 1, but at reaction temperatures of 750, 800, 900, 1030 and 1050 ^o C and, accordingly, the process time of 48, 35, 16, 7 and 6.5 hours

Examples 7 to 12 are similar to example 1, but as the substrate used carbon black fractions of 1.0 - 3.0 mm at reaction temperatures of 730, 750, 800, 900, 1030 and 1050 ^o C and, accordingly, the process time 69, 48, 35, 16 , 7 and 6.5 hours

Examples 13 to 18 are similar to example 1, but as the substrate used carbon black fractions of 3.0 - 6.0 mm at reaction temperatures of 730, 750, 800, 900, 1030 and 1050 ^o C and, accordingly, the process time 69, 48, 35, 16 , 7 and 6.5 hours

Examples 19 to 24 (prototype) similarly to example 1, but as the substrate used carbon black fractions of 0.2 - 6.0 mm, and carburization was carried out at temperatures of 730, 750, 800, 900, 1030 and 1050 ^o C and the process time, respectively 68, 48, 35, 16, 7 and 6.5 hours. The obtained carbon material was classified according to the fractions 0.2 - 1.0, 1.0 - 3.0 and 3.0 - 6.0 and the apparent density was determined (Table 2).

 The results of the experiments obtained by carburizing granular soot with different particle size distribution and at different temperatures are given in table. 1. Data analysis shows that the invention allows to obtain a carbon granular material more uniform in quality with the optimal value of the apparent density for each of these fractions and increased productivity of the process.

 Table 2 shows the values of the apparent density of the fractions (0.2 - 1.0; 1.0 - 3.0; 3.0 - 6.0 mm) of the finished product obtained by the known method, after classification. The data presented show that the resulting product is heterogeneous. Moreover, the heterogeneity in properties increases at extreme values of the temperature range considered in examples 19-24.

Claims (1)

A method of producing carbon granular material, including heating a moving layer of granular soot in a horizontal rotating reactor, supplying gaseous or vaporous hydrocarbons to a moving layer, followed by thermal decomposition at 250-1200 ^o C and deposition of pyrocarbon on soot, characterized in that, in order to increase the apparent density of the material and the performance of the process, soot granules before heating are classified into fractions of size 0.2-1 mm, 1-3 mm and 3-6 mm and pyrocarbon deposition on soot for each One of these fractions is carried out at 900-1030 ^o C, 800-900 ^o C and 750-800 ^o C, respectively.

Images