| 摘要 |
In the production of gaseous olefins by cracking hydrocarbons such as crude oil or a crude oil distillate at 680 DEG -850 DEG C. in the presence of fluidized, hot, inert, heat carrier particles which <PICT:0926844/III/1> circulate between the reactor and a regenerator where the heat necessary for the cracking is supplied by burning carbon deposits on the particles and by combustion of part of the oil residues boiling above 200 DEG C. from the product which have been used to quench the vapour leaving the reactor to below 400 DEG C., the particles used have a grain size between 0,05 and 4 mm., at least 10% having a size above 1 mm. The feedstock, having a final boiling point of 200 DEG -400 DEG C., is injected into reactor 1 by line 9 where it is contacted with a fluidized bed of hot inert solids, e.g. aluminium silicate containing more than 50% by weight of alumina, corundum, sillimanite or mullite. The cyclone 11 is adjusted so that the vapours leaving it still contain 5-50 grams of solid per normal cubic meter which prevent carbon deposits in the exit pipe. The vapours are quenched in vessel 13 with residual oil from line 15; this also removes the solids from the vapours. From receiver 17 the vapours are introduced into fractionating column 19 where gases and gasoline are recovered overhead, fuel oil by line 28, a rinsing oil for pump 26 by line 25 and quenching oil by line 24. Solids leave reactor 1 by standpipe 3 which is at an angle to the vertical of not more than 20 degrees and passed to regenerator 2 by riser 4 using air, flue gas or nitrogen introduced by line 30; the amount of solid leaving the reactor is regulated by a gas stream 29. In the regenerator carbon deposits and oil from line 32 are burned with sufficient excess oxygen to ensure an oxygen content of 0,3-3% by volume in the flue gas. This gas may be used as a conveying gas. Solids are returned to the reactor by pipes 5 and 6, steam being used as the conveying gas. Steam is also preferably used as the fluidizing gas.
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