Laboratory appts. for studying steam cracking - with inductively heated helical tube reactor, has turbulent flow, reducing wall effects

摘要

Laboratory appts. for studying the steam cracking of gas or liq. hydrocarbons comprises: means of injection for feedstock and diluent, preheater for the feedstock/diluent mixt., reactor, means of quenching the reactor effluent (e.g. with water) and sepg. liq. and solid prods., and a system for measuring and sampling the prod. gas. The reactor can be an inductively-heated helical tube of refractory steel. Feedstock flow rates can be 10-500, pref. 30-300 ml liq./h. The reactor tube may be e.g. of Incoloy 800, 2 m long and of 4 mm i.d., wound on a graphite core. The whole may be mounted in a silica tube with flowing N2, surrounded by the coil for inductive heating. Flow inside the tube is turbulent (unlike conventional laboratory reactors), reducing the catalytic effect of the walls. Induction heating improves heat transfer, gives an even temp., up to 1000 deg.C, over the whole tube, and gives thermal equilibrium within 0.5 h. Cracking can be studied over a wide range of conditions, while reducing the catalytic effects of the reactor wall. Thus, coking and CO prodn. (wall effects) are less than in conventional appts., and comparable with full-scale levels: this facilitates study of heavy feedstocks. Comparisons can be made of the effects of feedstock pretreatment on cracking yields. The reactor is compact.