UA146599U - METHOD OF OBTAINING PYROGRAPHITE - Google Patents

Abstract

The method of obtaining pyrographite includes heating the source hydrocarbon with an electric current and cooling the finished product. In the reaction zone of heating, a fluidized bed of fine pure graphite is created by passing a hydrocarbon and an inert gas through it, and heating is carried out by passing an electric current through the fluidized bed. Methane or propane-butane mixture is used as a hydrocarbon.

Description

A useful model belongs to the methods of obtaining pyrographite. The method can be used to obtain pyrographite with a low yield of amorphous carbon with further application in ultra-high temperature technology, atomic energy, mechanical engineering, electrical engineering, aircraft and rocket engineering.

There is a known method of obtaining pyrographite (US patent No. 3,720,499 dated 13.03.1973 IPC СО18В 31/10), which includes a stage in which a stream of hydrocarbon gas is fed through a nozzle into the reaction chamber without reducing the pressure, in which an electric arc is created. An electric arc heats the hydrocarbon gas to a temperature of 1500 "C and higher, which causes the pyrolysis of the hydrocarbon gas with the formation of amorphous carbon and pyrographite. The method includes an additional stage of periodic removal of pyrographite from the reaction zone to ensure a continuous process of pyrographite formation. The creation of an electric arc significantly complicates the controllability of the process, and the formation of amorphous carbon increases the specific consumption of hydrocarbon gas.

A known method of obtaining highly oriented pyrographite (USSR patent Mo 1427766 A1 dated 15.12.1990 IPC СО1В 31/04) by exposure to laser radiation with a power of 5:105-107

W/sme and duration of 108-109 s on heat-treated graphite in the medium of hydrocarbon gas, which is fed into the laser beam under a pressure of 0.2 MPa. The use of laser radiation as a heat source complicates the technological equipment and makes it impossible to control the temperature of the process.

The closest analog in terms of technical essence to the proposed one is the method of obtaining pyrographite (US Patent No. 3,442,617 dated 06.05.1969 IPC СО1В 31/00), which includes high-temperature oxidation or halogenation of hydrocarbons with simultaneous thermal decomposition of hydrocarbons. Gases are fed through injectors with nozzles into a furnace with a ring heater, which is heated to a temperature of 1900-2000 C. As a result of exposure to high temperature, pyrographite is obtained, and the formed hydrogen reacts with oxygen or halogens. Acetylene is used as a hydrocarbon. The ring heater is made of graphite, through which an electric current is passed, and due to electrical resistance, it is heated.

Since heating takes place through a ring heater, the method is characterized by high specific energy consumption. A layer of pyrographite deposited on the heater leads to uneven heating of the reaction zone, as a result of which a large amount of

From amorphous carbon. The use of halogens leads to the formation of toxic compounds of hydrogen with halogens.

The useful model is based on the task of improving the method of obtaining pyrographite, in which, thanks to the creation of a fluidized bed of finely dispersed pure graphite by passing a mixture of hydrocarbon and inert gas through it and heating the fluidized bed by passing an electric current through it, uniform heating of the reaction zone is ensured, thanks to which the output of amorphous carbon, the possibility of the formation of toxic compounds is excluded, and specific energy costs are also reduced.

In the pyrographite production method, which includes heating the starting hydrocarbon with an electric current and cooling the finished product, according to a useful model, a fluidized bed of finely dispersed pure graphite is created in the reaction zone by passing a hydrocarbon and an inert gas through it, and heating it is carried out by passing an electric current through fluidized bed, and methane or a propane-butane mixture is used as a hydrocarbon.

Thanks to a set of distinctive features, a reduction in the amount of formed amorphous carbon due to uniform heating of the reaction zone when using a fluidized bed is ensured, the absence of halogens in the reaction zone excludes the possibility of the formation of toxic compounds, and since heat is generated directly in the reaction zone, specific energy consumption is reduced.

The method of obtaining pyrographite is carried out as follows: the raw material in the form of finely dispersed pure graphite is loaded into the reaction zone of an electrothermal fluidized bed reactor, a mixture of methane or propane-butane and inert gas is fed to create a fluidized bed and carry out the decomposition process. Due to the passage of an electric current through the fluidized bed, it is heated to a temperature of 1900-3000 C, which causes the decomposition of hydrocarbons with the precipitation of pyrographite and the formation of hydrogen. The starting material is kept at the indicated temperatures for 3 hours, after which it is unloaded into a refrigerator, where it is cooled. After cooling, the product is ready for sale.

Example 1 (according to the method - the closest analogue):

Pyrographite is obtained by high-temperature oxidation or halogenation of acetylene with its simultaneous thermal decomposition. The source gases - acetylene, oxygen or halogens are fed through injectors with nozzles into a furnace with a ring heater, which is heated to a temperature of 1900-2000 "С. Under the influence of high temperature, high-temperature oxidation or halogenation of hydrocarbons is carried out with simultaneous thermal decomposition of hydrocarbons

The ring heater is made of graphite, through which an electric current is passed and due to electrical resistance, it is heated. The formed hydrogen reacts with oxygen or halogens to form water and compounds of hydrogen with halogens. The starting material is kept for 3 hours, after which it is unloaded into a refrigerator, where it is cooled. The proportion of pyrographite is 20 wt. 96, the proportion of amorphous carbon - 80 wt. 9o, specific energy consumption - 52 kWh/kg.

Example 2 (according to the proposed method):

The starting material in the form of finely dispersed pure graphite is loaded into the reaction zone of the electrothermal fluidized bed reactor, and a mixture of methane or propane-butane and inert gas is fed to create the fluidized bed. By passing an electric current through the fluidized bed, it is heated to a temperature of 1900 "С, which causes the decomposition of hydrocarbons with the precipitation of pyrographite and the formation of hydrogen. The starting material is kept for 3 hours, after which it is unloaded into a refrigerator, where it is cooled. Part of pyrographite 40 wt. 956 , the proportion of amorphous carbon is 60 wt 95, the specific energy consumption is 43 kWh/kg, and there are no compounds of hydrogen with halogens in the outgoing gas.

Example C

As in example 2, but the heating temperature is 2300 "С. The proportion of pyrographite is 55 95, the proportion of amorphous carbon is 45 95, the specific energy consumption is 38 kWh/kg. There are no compounds of hydrogen with halogens in the outgoing gas.

Example 4

As in example 2, but the heating temperature is 2700 "C. The proportion of pyrographite is 75 wt. 96, the content of amorphous carbon is 25 wt. 956, the specific energy consumption is 30 kWh/kg. There are no compounds of hydrogen with halogens in the exhaust gas.

Example 5

Zo As in example 2, but the heating temperature is 3000 "С. The fraction of pyrographite is 90 wt. 95, the fraction of amorphous carbon is 10 wt. 95, and the specific energy consumption is 26 kWh/kg. There are no compounds of hydrogen with halogens in the outgoing gas .

Table

Comparison of the characteristics of the closest analogue and the claimed method 00opzhshnyo | The most beautiful | in

Indicator The closest analogue (Part of pyrographite, mass. 9e | 20... | 40 | 55 | 75 | Yu Ks

As we can see from the table, the largest proportion of pyrographite and the lowest specific energy consumption are at a temperature of 2700-3000 C, which is explained by the compensation of the heating time with a high temperature. Heating above 3000 "C causes technological difficulties. In the proposed method, it is possible to increase the temperature to more than 2000 "C, because the presence of halogens does not interfere, as in the closest analogue.

Comparison of the proposed method with the closest analogue indicates the following advantages: 1). The proposed method makes it possible to obtain a higher yield of pyrographite in comparison with amorphous carbon. 2). The proposed method excludes the possibility of the formation of toxic compounds of hydrogen with halogens. 3). The proposed method ensures an increase in the energy efficiency of the pyrographite production process.

Thus, the proposed method of obtaining pyrographite ensures a decrease in the amount of formed amorphous carbon, excludes the possibility of the formation of toxic compounds and reduces specific energy consumption.

Claims (1)

USEFUL MODEL FORMULA The method of obtaining pyrographite, which includes heating the initial hydrocarbon with an electric current and cooling the finished product, which is characterized by the fact that in the reaction zone of heating, a fluidized layer of finely dispersed pure graphite is created by passing hydrocarbon and inert gas through it, and its heating is carried out by passing electric current through a fluidized bed, and methane or a propane-butane mixture is used as a hydrocarbon.