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Petrochemical engineering |
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The polymerisation reaction is applied in particular to the petrochemical bases.
The main petrochemical bases are: naphtha, diesel, and butane. These petrochemical bases are treated in chemical plants in units called steam crackers. The aim is to break down the molecules under the action of heat in the presence of steam to obtain the following basic products:
- Alcenes (olefins): ethylene, propylene and butadiene (ethene, propene, butene);
- Aromatic hydrocarbons (cyclic unsaturated hydrocarbons): benzene, toluene, xylene;
- Synthesised gas, a mixture of hydrogen and carbon monoxide, CO, produced by the partial oxidation of methane from natural gas. |
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| Diagram illustrating the steam cracking process. |
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In general steam crackers are situated on the sites of large refineries: indeed they use products resulting from the refining operation. The technique of steam cracking is a close cousin to the techniques used in the refining process.
Once our polymers are manufactured, there is still a lot to do! In fact they often take the form of granules or powders. They must be transformed to give them shape, texture, colour and the properties that we expect from them: resistance to shocks, heat and wear, rigidity, flexibility or elasticity, and also pleasantness to the touch … To this end, they will undergo a series of treatments: heating, fusion, moulding, adding of other products … but there we are leaving the petrochemical framework and entering that of the plastics industry, the textile industry and the cosmetics industry! |
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| View of a steam cracker, belonging to the petrochemical activity in the refinery at Feyzin (France). This plant is used for the production of the main intermediaries in chemical synthesis by the pyrolisis of petrol at more than 820°c, in the presence of steam. |
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| View of the aromatic essence extraction plant (Feyzin, France). |
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