By endothermic reaction mechanism, two molecules of methane combine in a catalytic reactor to produce acetylene and hydrogen as products. This can be achieved by partial oxidation of methane; it is a well established in process industries and continuous improvements observed in this technology. The objective of the partial oxidation is to provide the required heat for combination reaction by incomplete combustion.
Technology available for acetylene production from methane and natural gas:
- Electric methods: arc and plasma
- Combustion methods: partial oxidation and pyrolysis
Process material required for acetylene manufacturing by partial oxidation method:
- Air (Oxygen)
- Process steam
- Dimethylformamide solvent
Process flowsheet of acetylene manufacturing from methane brief description:
Preheating operation helps to increase the feed temperature and decrease the reaction time in the reactor along the length, by this residence time decreases too. Possibility of methane cracking reaction increases, which occur in the presence of nitrogen, will produce carbon atom and hydrogen. Carbon atom reacts with the radicals of methane to form acetylene. This mechanism provides the feasibility of using air directly rather than pure oxygen for partial oxidation.
Methane and air are preheated to 500oC, separately in fired heaters. Combustion is done at first stage of the reactor and temperature is raised to 1500oC. At this temperature, methane is converted to acetylene at the reaction zone. At bottom of the reactor, water is sprayed to prevent acetylene cracking. The scrubber removes carbon formed in the process using coke and water. Dimethylformamide solvent separates the acetylene from CO and H2 and unreacted CH4 in absorber. Pure acetylene is produced in a acetylene separation column and solvent is recycled.
Main process operation applied in the process flowsheet of acetylene manufacturing from methane:
- Partial combustion
- Soot removing
- Acetylene recovery
Process flowsheet of acetylene production by partial (incomplete) combustion of methane
Other process options: