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1. (WO1994005743) PROCESS FOR CRACKING HYDROCARBON CHARGES AND NON HYDROGENATED C4 FRACTIONS

Pub. No.:    WO/1994/005743    International Application No.:    PCT/EP1993/002240
Publication Date: Fri Mar 18 00:59:59 CET 1994 International Filing Date: Sat Aug 21 01:59:59 CEST 1993
IPC: C10G 9/14
Applicants: LINDE AKTIENGESELLSCHAFT
ZIMMERMANN, Heinz
SCHWAB, Wolfgang
Inventors: ZIMMERMANN, Heinz
SCHWAB, Wolfgang
Title: PROCESS FOR CRACKING HYDROCARBON CHARGES AND NON HYDROGENATED C4 FRACTIONS
Abstract:
The invention concerns a process for the joint cracking of hydrocarbon charges (1), especially naphtha, and non hydrogenated C4 fractions (4b) in pyrolysis furnaces to produce olefines, in which the whole of the charge to be cracked is preheated in the convection region of the pyrolysis furnace by the flue gases from the radiant region with the addition of process steam (4a) and then subjected to thermal cracking in the radiant region. According to the invention, the C4 fraction (4b) is not fed into the convection region together with the hydrocarbon charges, as is usual, but is heated in mixture with process steam (4a) in the convection region (9) and then mixed with the hydrocarbon charge (2, 5) and reheated together before being fed into the radiant region (10). The heated mixture of process steam and C4 fraction can be mixed with the hydrocarbon charge at several points. Advantageously, in the process of the invention, superheated process steam is introduced or the process steam in the mixture of it and C4-hydrocarbons is superheated before being mixed with the hydrocarbon charge. Particular advantages are obtained if the C4 fraction amounts to up to 25% wt. and preferably up to 10% wt. of the hydrocarbon charge. The C4 fraction may consist of up to 100% wt., and preferably 30 to 60% wt., of butadiene.