Revamping an Existing Aromatics Complex with Simulated Moving-Bed Reactor for p-Xylene Production
TL;DR: In this article, a simulated moving-bed reactor (SMBR) for the production of p-xylene is studied as part of a proposal to modify an existing aromatics complex in order to increase the output of benzene and xylene.
Abstract: A simulated moving-bed reactor (SMBR) for the production of p-xylene is studied as part of a proposal to modify an existing aromatics complex in order to increase the production of benzene and p-xylene. The proposed complex includes a single-stage crystallization unit to further purify high p-xylene streams from a selective toluene disproportionation and said SMBR units. Mass balances for two cases are estimated, namely, the current flow of reformate fed to the complex and a twofold flow. Results show significant increases of benzene and p-xylene for both cases compared to the current production of the complex.
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TL;DR: The aromatics complex is a petrochemical facility where the main products are benzene and p-xylene, and the xylene isomer is produced through an energy-intensive cycle loop in which the p xylene separa...
Abstract: The aromatics complex is a petrochemical facility where the main products are benzene and p-xylene. The xylene isomer is produced through an energy-intensive cycle loop in which the p-xylene separa...
7 citations
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TL;DR: In this article, solid-liquid phase equilibria for the systems idane/nitrobenzene, indane/1,2-dichloroethane, Indane/ 1,4-dioxane, ndane/dodecane, acenaphthene/1.4-xylene, tetrachloromethane/2.5-hexane, TTRAC-2-undecanone, 1.2-oxylene, 1,3-axylene, and 1.4x
98 citations
TL;DR: In this article, a kinetic study of toluene alkylation with methanol was performed over pure HZSM-5, mordenite and ZM13 catalysts, and a simplified power law kinetic model consisting of three reactions was developed to estimate the activation energies of methylation and disproportionation simultaneously.
65 citations
TL;DR: A two-level optimization procedure based on the concept of “separation volume” and equivalent true moving bed modeling strategy is proposed to optimize an existing simulated moving bed (SMB) unit for p -xylene separation from mixed xylenes.
59 citations
TL;DR: In this paper, the effect of reaction parameters such as temperature and weight hourly space velocity (WHSV) on para selectivity was considered, and the relationship between extent of silica deposition and para-selectivity was established.
Abstract: Selective disproportionate of toluene to p-xylene was studied over modified MFI aluminosilicate. The relationship between extent of silica deposition and para selectivity was established. The effect of reaction parameters such as temperature and weight hourly space velocity (WHSV) on para selectivity was considered. Kinetics of reaction in the temperature range 723--773 K was carried out. The estimated activation energy value is lower than reported for toluene disproportionation in the literature. This has been explained on the basis of enhanced intracrystalline diffusion in the modified zeolite.
43 citations
TL;DR: In this article, the authors provided an equilibrium product distribution for xylene isomerization for all temperatures above T = 250 K and provided an analytical analysis of the product distribution percentages derived from the thermodynamic measurements.
Abstract: Thermodynamic equilibria calculations based upon new calorimetric and physical-property measurements published in the first four papers of this series corroborate the assertion by Amelse (1993) that the existing thermodynamic data are in error. The largest errors are associated with the entropy of o-xylene in the liquid and gas states. New equilibria calculations described here are in excellent accord (within 0.7%) with product distributions determined experimentally by Amelse (1993). Deviations derived with previously available thermodynamic property compilations are three to four times larger. Statistical analysis shows that the uncertainties in the product distribution percentages derived from the thermodynamic measurements are approximately 2.5% for m-xylene, 2.0% for p-xylene, and 1.5% for o-xylene under typical processing conditions. Equations are provided for the calculation of equilibrium product distributions for xylene isomerization for all temperatures above T = 250 K. Claims in the scientific ...
35 citations