To provide a thermal cracking process that can be stably operated for a long period of time by inhibiting the sludge from accumulating in the preheater and the heat exchanger tubes and preventing the preheater and the heat exchanger tubes from clogging.
The feedstock including naphtha is thermally cracked in the cracking furnace after the hydrogen concentration is adjusted to ≥0.1 ppm. by weight in the feedstock. The feedstock of ≥0.1 ppm. by weight of hydrogen concentration is used as the cracking feedstock and the feedstock of 2-16 ppm. by weight is used in a preferred embodiment. Too low hydrogen concentration causes the accumulation of sludge and the preheater and the heat exchanger tubes are clogged with the sludge in an extreme case. In the case of the too high hydrogen concentration the treatment costs in the purifier may be increased after the cracking furnace.
WATANABE KOJI
KIZAKI JUNYA
