|Special methods of chemical technology are applied in carbon production. Artificial graphite is produced by sintering anthracite or petroleum coke between carbon electrodes at 2260° C (the Acheson process) and then used as lubricant and electrodes for metals electrodepositing processes. |
There are several industrial methods of carbon producing, and all of them are based on thermal (pyrolysis) or thermal-oxidative decomposition of liquid or gaseous hydrocarbons. In dependence of the method and used batch materials several processes may be distinguished:
Furnace process - In the oil furnace process a liquid hydrocarbon feedstock is heated and injected continuously into the combustion zone of natural gas-fired flow reactors, where it is cracked (decomposed) to form carbon black. Primary quench water cools the gases to stop the cracking. The exhaust gases entraining the carbon particles are further cooled to by passage through heat exchangers and direct water sprays. The black is then separated from the gas stream, usually by a fabric filter and granulated.
Lamp process - This is a continuous operation which is processed in flow reactors. A liquid hydrocarbon feedstock is evaporated in the heated bowl. The effluent vapour creates external air flow into the reactor through a ring gap between the feedstock retort and the delivery hood. The flows are controlled partially. The reactor offtake channel is cooled by water through the wall. Carbon black is separated from the waste gas and stored.
Thermal Process - The thermal process is a cyclic operation in which natural gas is thermally decomposed in two reactors used in normal operation. In the first gas (natural gas or acetylene) and air mixture heats the lining. The effluent gas from the first reactor is cooled by water sprays and the black is collected in a fabric filter. The filtered gas is used as a fuel to heat a second reactor. When the first reactor becomes too cool to crack the natural gas feed, the positions of the reactors are reversed, and the second reactor is used to crack the gas while the first is heated. Normally, more than enough hydrogen is produced to make the thermal black process self-sustaining, and the surplus hydrogen is used to fire boilers that supply process steam and electric power.
Channel process - A periodical process which takes in special periodically operating chambers with channel burners installed on the bottom. The burning feedstock flame encounters with metal water-cooled chute. That terminates the oxidation process yielding carbon black collected inside the chamber.