Influence of Hydrocarbon Partial Pressure in the Cracking Oven

4 Influence of Hydrocarbon Partial Pressure in the Cracking Oven 

The reaction mixture leaves the cracking furnace at 880 °C and should be cooled instantaneously to preserve its composition as usually all changes in composition by consecutive reactions reduce the value of the cracked gas. Industrial plants are designed to limit the residence time of the hot gas in the adiabatic section between the furnace outlet and the quench-system cooling zone to less than 10% of the residence time in the radiant zone. 

Transfer-line heat exchangers are characterized by the following design objectives  

The dry products from the drying unit are first separated in the C2/C3+ spUtter. The C2-fraction contains hydrogen, acetylene, ethene, and ethane. The C3+-fraction contains propyne, propene, propane, the C4 products (butadiene, isobutene, n-butenes, butane), and the C5+ fraction, which is unified with the pygas collected from the cooling and compression units. 

The production of polymerization grade ethene from the C2-fractions involves as the first step the separation of hydrogen and methane. From the remaining C2-stream, acetylene has to be removed completely as it has a detrimental effect on 

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