Showing papers in "Industrial & Engineering Chemistry Process Design and Development in 1980"

Hydrodynamic Properties of the Fischer-Tropsch Slurry Process

Abstract: The indirect coal liquefaction route to produce transportation fuels, Le., the Fischer-Tropsch synthesis, may favorably be carried out in the slurry phase. The paper reports on measurements of gas holdup and heat and mass transfer in bubble column slurry reactors of 4.1 and 10 cm diameter. The study was done under conditions prevailing in the Fischer-Tropsch slurry reactor (Rheinpreusen-Koppers process). The results enable, at least, an estimation of the majority of hydrodynamic properties involved in designing a slurry-phase reactor. Under the conditions of the Fischer-Tropsch synthesis the slurry reactor can be treated as a two-phase system which permits some conclusions concerning the favorable flow regimes and gas velocities.

The Reaction between Hydrogen Sulfide and Spherical Pellets of Zinc Oxide

Abstract: The reaction between hydrogen sulfide and spherical pellets of zinc oxide was studied in a microbalance reactor at 375/sup 0/-800/sup 0/C. The gaseous mixture contained 1-6% H/sub 2/S diluted with hydrogen (added to stabilize H/sub 2/S) and nitrogen, with a 5:1 H/sub 2//H/sub 2/S molar ratio. Rapid and almost complete reaction occurred at 600/sup 0/-700/sup 0/C. Near 800/sup 0/C, slow decomposition of ZnO led to a vapor-phase reaction and deposition of nonporous ZnS on the pellet surface, which prevented further reaction. At below 600/sup 0/C, the reaction stopped well before total ZnO conversion was obtained. Experimental time-conversion results for the 600/sup 0/-700/sup 0/C range, where pore diffusion was the controlling resistance, were in good accord with values predicted by the Szekely et al. grain model. The strong deviation from the model predictions at lower temperatures were attributed to the dominant role of grain diffusion resistance. The H/sub 2/S-ZnO reaction is currently used in the desulfurization of hydrocarbon gases for synthesis of ammonia and has been suggested for sulfur removal in SNG processing.

Modified Soave Equation of State for Phase Equilibrium Calculations

Abstract: Using experimental vapor-liquid equilibrium data, Purdue scientists tested the various forms of the Soave equation of state that could be used for hydrogen-containing mixtures The original Soave method - with properly determined values of the interaction constant C/sub ij/ - appears to represent the data reasonably well, even for the systems containing heavy, non-paraffinic hydrocarbons The values of C/sub ij/ are correlated with the solubility parameters The modified Soave equation of Graboski and Daubert works well only for those systems containing light hydrocarbons

A Thermodynamic Approach to Steam-Power System Design

Abstract: Chemical industries in general consume great amounts of energy, and in the past several years it has become very important to make a strong effort to conserve energy in design and operation. Among the several kinds of problems faced in a steam-power system design, the problem of determining system structure and design conditions is most important. In solving the problem with directly acceptable results, it is desirable to build a sound basis for gaining deep insights into the energy conservation problem. The paper is concerned with a thermodynamic approach to steam-power system design. The practical usefulness of the present method is illustrated by solving a problem of steam-power system design in a petroleum refinery.

Nonisothermal determination of the intrinsic kinetics of oil generation from oil shale.

Abstract: A nonisothermal technique using various heating rates has been applied to the determination of the intrinsic kinetics of oil generation from oil shale. From an engineering standpoint the rate of oil generation can adequately be described by overall first-order kinetics with a constant activation energy of 199 kJ/mol. Various methods are applied to the determination of the kinetics parameters. The relative merits of these methods are discussed. The results are compared with data reported in the literature. The nonisothermal technique has the advantages of short experimental time and the elimination of difficulties due to the initial heat-up period accompanying the isothermal experiments.

Simultaneous Catalytic Hydrodenitrogenation of Pyridine and Hydrodesulfurization of Thiophene

Abstract: The study of the simultaneous catalytic hydrogenation of pyridine and hydrosulfurization of thiophene, model compounds representing sulfur and nitrogen content in oil shale and coal-derived liquid fuels was extended to higher, industrially relevant pressures, up to 7 MPa The reactions were carried out in a continuous plug-flow microreactor at 200 to 400C and thiophene and pyridine partial pressures of 124 kPa each, over a commercial 31% by wt NiO/15% MoO/sub 3//Al/sub 2/O/sub 3/ catalyst Thiophene hydrodesulfurization was inhibited by pyridine under all the conditions studied In the absence of thiophene, pyridine reached a thermodynamic equilibrium with piperidine above 350C at all pressures studied (11 4 to 7 MPa), but this equilibrium was not reached in the presence of thiophene because of the inhibition of pyridine hydrogenation and enhancement of piperidine hydrogenolysis The combined conversion of pyridine plus piperidine, ie, the over-all rate of hydrodenitrification, was enhanced by thiophene at > 300C and > 355 MPa