Catalytic Naphtha Reforming Research Articles

Catalytic reforming of naphtha from liquefaction of coal produced in the kansko-achinsk basin

The results obtained in reforming the coal and petroleum naptha cuts in a laboratory single-pass flow unit are presented. The tests were performed with commercial KR-108 polymetallic catalyst, catalyst charge 4 cm/sup 3/, pressure 1 MPa, feedstock space velocity 4 h/sup -1/, and hydrogen feed 1000 liters/liter of feed. The higher yield of reformate with the hydrotreated feed from coal liquefaction is explained by the higher contents of aromatic and naphthenic hydrocarbons in this naphtha. In reforming petroleum and coal naphtha cuts with identical distillation curves, this difference would be more pronounced. The wide-cut distillate was hydrotreated on commercial alumina-cobalt-molybdenum catalyst in a two-section reactor.

Effect of feed composition and operating conditions on catalyst deactivation and on product yield and quality during naphtha catalytic reforming

The effect of operating conditions and feed compositions on the yield and quality of reformate and on catalyst deactivation were studied for naphtha reforming over an industrial bimetallic reforming catalyst. The aromatics yield showed a maximum in the pressure range 7-10 bar, while the carbon deposition decreased with increasing pressure. Increasing temperature led to an increase in the yield of aromatics at the expense of reformate. Hydrogen: hydrocarbon ratios (H/HC) in the range 7-12.7 did not show any pronounced effect on reformate or aromatics yield: however, lower H/HC ratios (eg: 3.6), gave decreased aromatics and increased carbon. Quantitative correlations are developed for these observations and mechanistic arguments are presented to explain the results. Feed composition effect studies were carried out by using several naphtha blends having a wide variation in the paraffin, naphthene and aromatics content. At any reforming severity, yields of reformate and aromatics are higher and coke deposition is lower for a naphthene-rich naphtha. The temperature requirement for attaining a particular product quality (RONC) is lower for naphthene-rich naphtha than for paraffin-rich naphtha. Correlations between the reformate octane number and reformate yield have been obtained for different naphtha feed stocks.

Experience in operation of L-35-11 reformer unit at Novo-Ufa refinery

This article reports on the catalytic reforming of naphtha in a chemical reactor. Sections of the reformer unit were reconstructed. The circulating-gas drying system with molecular sieves was taken out of operation, the blocking system was considerably simplified, the relief valve and venting flow plan were converted from an open system to a closed system to the flare, certain components of the compressor system and air-cooled condensers were modernized, and arrangements were made for feed recirculation. The use of a straight-run naphtha cut with an IBP of 75-80/sup 0/C and an EP of 188-193/sup 0/C, in place of the 85-185/sup 0/C cut that is specified as feed, was studied and experimentally tested. Three years of operating experience with KR-108 catalyst in a 35-1/2 unit indicate the advantages of KR-108 over KR-104A.

The dehydrocyclization-controlling site in bifunctional reforming catalysts

Bifunctional catalysts which contain Pt or Pt and a second metal supported on an acidic carrier such as y-Al203 are widely used in the catalytic reforming of petroleum naphtha. In the classical scheme of bifunctional catalysis proposed by Mills et al. [I], the metal function catalyzes (dejhydrogenation reactions of paraffins into olefins and naphthenes into aromatics while the acid function catalyzes skeletal rearrangements of olefins. Such a scheme gives a good qualitative description of the macroscopic phenomena observed in catalytic reforming. However, the reality is known to be much more complex. The metal function alone can catalyze hydrogenolysis, closure and opening of fiveand six-membered rings, and dehydrocyclization as well as isomerization [2]. Similarly, the acid function can catalyze isomerization, ring opening, ring closure and ring enlargement. reactions. It has also been found that. dihydrogen dissociatively adsorbed on the Pt function can volatilize some of the coke on the acid function, presumably by spillover of adsorbed H atoms [3]. So, a myriad of reactions occur on the surface of a bifunctional reforming catalyst. In some of these reactions, the reacting species uses only one type of site during its residence on the surface, while in others it seems to shuttle between two different types of sites. If, during time-on-stream, one catalyst function is poisoned preferentially, the deterioration in overall performance will depend on the quantitative contribution of this particular function to the overall conversion. In the extreme case where the multiplicative product of the number of sites and the turnover frequency for function A is several orders of magnitude larger than that for function B, a partial poisoning of B will result in a proportional decrease of the overall conversion for all reactions involving B, while a similar poisoning of A will have little or no effect on these reactions. In the light of these considerations, it is of interest to know which one of the two functions, acid or metal, is the critical function of a reforming catalyst. Contradictory claims exist in the literature. It has been reported that (i) coking of the acid function controls deactivation [4], (ii) coking of the metal function controls deactivation [5], (iii) coking of both functions may be important in controlling deactivation [6],

Analysis of Temperature-Time Data for Deactivating Catalysts

A simple mathematical model of a single irreversible reaction with n-th order, concentration-independent catalyst deactivation is proposed. The model predicts the time-temperature relationship for the constant-conversion mode of operation and can be used to optimize temperature policy in a batch reactor. The applicability of the model to pilot-plant data from hydrocracking of gas oil and catalytic reforming of naphtha is demonstrated and the effects of process variables, such as start-of-run temperature, space velocity, and conversion level on the fouling rate are examined. The model has successfully described both the linear and exponential portions of the reaction temperature-time curves and demonstrated a linear correlation (on a logarithmic basis) between fouling rate and the work function, i.e., the product of conversion and space velocity, of the catalyst.

Catalytic Naphtha Reforming

Abstract During the past twenty years, the demand for high octane motor fuels has resulted in the installation of catalytic naphtha reforming capacity at a much higher rate than was forecasted by some of the

Catalytic Reforming of Naphtha and its Application to Aromatics Production (Part 2)

Catalytic Reforming of Naphtha and its Application to Aromatics Production (Part 2)

Catalytic Reforming of Naphtha and its Application to Aromatics Production (Part 3)

Pyrolytic gasoline, by-product of ethylene manufacturing, contains much aromatics, from which benzene, toluene and xylene are recovered by two-stage hydrotreating and solvent-extraction. By hydrogenation, a small quantity of aromatics is lost through hydrogenation, and the hydrocarbons convertible to aromatics, if any, contained in the feed, can not be converted. On the other hand, by reforming of the gasoline, it is expected to obtain additional aromatics by dehydrogenation of naphthene.An experiment of reforming of pyrolytic gasoline was carried out, using a small reactor at 20∼30kg/cm2, 375∼510°C, the LHSV of 1.5hr-1 and H2 to hydrocarbon molar ratio of 6∼8. At the higher temperature (500°C) and the lower pressure (20kg/cm2), more aromatics were obtained than originally contained in the feed, and the bromine number as well as the sulfur content of the reformate were low enough for extraction.Reforming of pyrolytic gasoline is superior to conventional hydrotreating, with respect to higher aromatics yield and self sufficiency of hydrogen.

Catalytic Reforming of Naphtha and its Application to Aromatics Production (Part 1)

Catalytic Reforming of Naphtha and its Application to Aromatics Production (Part 1)

Production of Heavy Aromatic Hydrocarbons by Catalytic Reforming (2)

Studies were carried out for the purpose of production of C9, C10 aromatic hydrocarbons by catalytic reforming of heavy naphtha.1) Naphtha fraction with the boiling range from 100°C to 210°C, which was obtained from Gach Saran crude, was further fractionated into fractions, each having a 10°C boiling range. These naphtha fractions were then reformed, using a platinum-alumina commercial reforming catalyst. It was confirmed by the experiments that the fraction ranging from 130°C to 170°C and from 150°C to 205°C gave higher yields of C9, C10 aromatics, respectively. In addition, the relationship between the boiling range of naphtha and the yields of methylethybenzene (MEB), trimethylbenzene (TrMB), and tetramethylbenzene (TeMB) was also investigated. Components of these three isomers-i.e. MEB, TrMB, TeMB-in the reformed naphtha remained constant without regard to the boiling range of the feed naphtha.2) Straight run Gach Saran naphtha (125∼190°C) was reformed at the temperature 450∼530°C, the pressure 10∼50atm., the lipuid hourly space velocity 0.6∼4 and the mole ratio of hydrogen to hydrocarbon 5∼15. From the data obtained, the relationship between the operating condition and yields or compositions of C6∼C11 aromatic hydrocarbons, particularly MEB isomers, TrMB isomers, TeMB isomers and durene fraction in those reformates was investigated.