Method and device of the thermal conversion of hydrocarbons, aliphatic hydrocarbons more unsaturated that the starting products, combining a step of the steam cracking and a step of the pyrolysis

摘要

A process for the continuous pyrolysis and de-coking in a reaction zone comprises a pyrolysis zone (40) made of a refractory material and consisting of heating and cooling zones. The heating zone comprises at least 2 rows (1.2) parallel to the axis of the reactor separated by a partition (70) of refractory material between successive rows. One of the rows receives hydrocarbons and water vapour and the other mainly water vapour. The rows comprise parallel heaters (8) encased in sheaths (7) perpendicular to the axis of the reactor. Coke deposits in the reaction zone. The C2+ hydrocarbon charge , at a temperature suitable for vapour cracking, circulates in vapour cracking zone containing at least 2 tubes coupled to supplies of the charge and water vapour. One of the tubes is supplied only with water vapour to provide for de-coking of the tube. The wt. ratio of water/charge is between 0.5 - 20. The vapour cracking current is circulated through a row of the pyrolysis zone and the de-coking current circulates through another row. The exit temperature of the currents from the pyrolysis reactor is at least 850 degrees C and hydrocarbons containing at least one acetylenic compound are recovered. Also claimed is a pyrolysis and de-coking unit for effecting the process.