| 摘要 |
<p>1,177,181. Thermal cracking. BADISCHE ANILIN- & SODA-FABRIK A.G. 12 May, 1967 [14 May, 1966], No. 22121/67. Heading C5E. C 2 -C 30 hydrocarbons are vaporized in a convection zone and thermally cracked in an externally heated coiled tube having a circular cross-section situated in a radiation chamber, at 800-900‹ C. in the presence of 0À3-1À0 kg. of steam per kg. of hydrocarbon wherein the residence times are less than 0À7 sec., the heat load is more than 40,000 col./sq. m./h. and the supply of heat to the individual tube sections by radiation from a plurality of burners at external tube wall temperatures of 880-1100‹ C. is regulated so that the external tube wall temperatures do not rise over the whole course of the coiled tube by more than 120‹ C., and are preferably substantially constant. In an example the cracking of a light naphtha (bp. 30-70‹ C.) to yield ethylene in 29À5% yield is described. The control of the external tube wall temperatures may be affected by using burners of differing nozzle size, or by varying the air supply to the burners. The coiled tube may be arranged so that the distance between parallel portions decreases towards the outlet from the radiation chamber.</p> |
