\u26a1 Steam Cracking \u2014 Quick Specs<\/p>\n
| Process type<\/td>\n | Thermal pyrolysis \u2014 non-catalytic<\/td>\n<\/tr>\n |
| Cracking temperature<\/td>\n | 750\u2013900\u00b0C (radiant section)<\/td>\n <\/tr>\n |
| Residence time<\/td>\n | 50\u2013300 milliseconds<\/td>\n<\/tr>\n |
| Primary feedstocks<\/td>\n | Ethane, naphtha, LPG, propane, butane<\/td>\n<\/tr>\n |
| Primary products<\/td>\n | Ethylene, propylene, butadiene, aromatics (BTX)<\/td>\n<\/tr>\n |
| CO\u2082 intensity<\/td>\n | 1.0\u20131.6 t CO\u2082 per tonne of ethylene (process emissions)<\/td>\n <\/tr>\n |
| Decoking cycle<\/td>\n | Every 30\u201390 days per furnace coil<\/td>\n <\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n <\/p>\n What Is Steam Cracking? Definition and Industrial Role<\/h2>\n
Steam cracking is a petrochemical process in which saturated hydrocarbons are thermally broken down into smaller, unsaturated molecules \u2014 principally ethylene and propylene \u2014 using high-temperature steam in the absence of a catalyst.<\/strong> Operating at temperatures between 750 and 900\u00b0C with residence times measured in milliseconds, it is the principal industrial method for producing the light olefins that underpin the entire petrochemical value chain, from polyethylene packaging to synthetic rubber.<\/p>\n <\/p>\n It is an endothermic process requiring an energy input of heat continuously to break down both the C=C and the C-H bonds in the hydrocarbon feed. Steam acts as the heat transfer medium, flowing through the furnace system and simultaneously diluting the hydrocarbon partial pressures (which in turn enhances olefin selectivity and possesses an additional coking advantage). The cracking process occurs by way of a free-radical chain mechanism at residence times of between 50 and 300ms.<\/p>\n The output stream from the furnace-systems, comprising a myriad of molecules such as ethylene, propylene, hydrogen, methane, butadiene and aromatics, must then be rapidly cooled and then separated in a twelve stage distillation process.<\/p>\n Around 300 million tonnes of ethylene per annum are manufactured worldwide by the gas-phase steam cracking process on an industrial scale – one of the largest volume processes in the entire chemical manufacturing industry. Typical world scale steam crackers produce between 1 and 1.5 million tonnes of ethylene per annum and require an investment of between 1 and 3 billion US dollars. The process then serves petrochemical and chemical process usage in a wide variety of products, including plastics, synthetic fibers, glues, solvents and pharmaceuticals.<\/p>\n Steam cracking remains the fundamental process of the petrochemical industry. It is the predominant producer of ethylene, propylene and other fundamental chemicals necessary for the manufacturing of all plastics, rubbers and fibres in modern society.<\/p>\n |
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