The Role of the Reactor Wall in the Thermal Hydrocracking of Polyaromatic Compounds

Abstract

With spargers of small orifice, water, acetone, and carbon tetrachloride display a laminar regime (with discrete bubbles). Only with water, however, is there a large laminar region. With all other liquids the gas flow was completely in turbulent flow a t superficial gas velocities above 4 ft/min.Of the liquid physical properties of density, surface tension, and viscosity, only density showed a significant effect on back-mixing and only in the 0.75-in. tube. The effect in the 1.8-in. tube was almost negligible. Nomenclature A = cross-sectional area B,D,H = constants C~G = heat capacity of gas CPL = heat capacity of liquidThe thermal hydrocracking of hydrindene (5OO0C, 80 atm) was found to be affected profoundly by the nature of the reactor wall. In a stainless steel (SS) reactor the conversion dropped and the selectivity changed while passing through the primary aging stage; aging of a gold-plated reactor resulted in an increasing conversion, starting from almost zero. In both reactors a steady state was established at essentially the same conversion and selectivity, which was not dependent on the s / V ratio of the reactor nor static or flow conditions. It is concluded that the a ring-opening reactions of indan, resulting in toluene and n-propylbenzene, are initiated and terminated at the aged reactor wall; the p ring-opening of indan leading to o-ethyltoluene is predominantly homogeneous and is not affected by the aged reactor wall.A rigorous calculation method for multistage multicomponent crystallization with equilibrium chemical reactions is presented. It can be used for designing multistage salting processes where different salts are in chemical and solid-liquid phase equilibria and are fractionally crystallized in different stages.

Coal devolatilization and hydrogastification

“…Preliminary results indicate some difficulties with carbon balances, since up to 20% of the carbon is unaccounted for at lower temperatures. The extent of cracking in the tube is unknown, although it appears to be significant based on the carbon balances and previous measurements (Gentry, 1928b;Brooks, 1966;Slotboom and Penninger, 1974). Finally, the acquisition of kinetic data would appear to be difficult.…”

Effect of benzene and thiophene on rate of coke formation during naphtha pyrolysis

“…The migration of metal particles on top of the growing carbon leads to catalytic coke formation. However, if these metal particles become encapsulated by carbon the formation of catalytic coke ceases resulting in a constant coking rate (Slotboom and Penninger, 1974;Trimm, 1977). Albright and Yu (1978) reported that relatively high levels of metal sulphides promote the formation of inactive coke containing no metal granules.…”

ChemInform Abstract: THERMAL HYDROCRACKING OF INDAN. EFFECTS OF THE HYDROGEN PRESSURE ON THE KINETICS AND ARRHENIUS PARAMETERS

“…Maybe a definite solution to the problem can be found in an effect which has not yet been considered in the preceding discussion, namely, the participation of the reactor wall. Extensive experimental work which was reported elsewhere [13] found that the hydrocracking does not proceed without an "active" reactor wall and that initiation and termination reactions must be wall-catalyzed reactions. Thus the interpretation of the afore-mentioned data in terms of a purely homogeneous gas reaction is incorrect.…”