The Parex Process for the Separation of p-Xylene

Rodrigues, A.E.; Pereira, Carla; Minceva, Mirjana; Pais, L.S.; Ribeiro, Ana M.; Silva, M.; Graça, Nuno S.; Santos, João C.

doi:10.1016/b978-0-12-802024-1.00005-7

Cited by 5 publications

(5 citation statements)

References 15 publications

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“…The process could be operated at low desorbent-to-feed ratios (<1) and high productivities >100 kg DMF/(m 3 ZIF-8·hr). These parameters are well comparable to industrial-scale peterochemical SMB processes such as the Parex process for aromatics production. , …”

Section: Introductionsupporting

confidence: 56%

“…These parameters are well comparable to industrial-scale peterochemical SMB processes such as the Parex process for aromatics production. 31,32 Distillation has been simulated as the primary separation mechanism for the downstream purification and recovery process. 14,15 Based upon our promising findings on adsorptive DMF separation, the present work focuses on detailed process modeling and technoeconomic analysis of complete separation processes for DMF purification along with recovery/recycle of BuOH and water (Table 2).…”

Section: ■ Introductionmentioning

confidence: 99%

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Separation and Purification of 2,5-Dimethylfuran: Process Design and Comparative Technoeconomic and Sustainability Evaluation of Simulated Moving Bed Adsorption and Conventional Distillation

Chiang

Bassas

Lively

et al. 2020

ACS Sustainable Chem. Eng.

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The furanic chemical 2,5-dimethylfuran (DMF) is an attractive biobased fuel and feedstock. High-yield biphasic processes for DMF synthesis from sugars employ higher alcohols such as n-butanol (BuOH) as solvents. This leads to a product containing <8 wt % DMF and byproducts in the BuOH solvent along with water. DMF process economics are dominated by separation costs for DMF purification and recycle of BuOH and water. We previously demonstrated efficient adsorptive separation of DMF with a stable ZIF-8 metal–organic framework adsorbent. Here, we present a detailed, comparative technoeconomic analysis and sustainability indicators of adsorptive versus conventional distillation separation processes to produce 98 wt % pure DMF at 100 metric tons/day. The novel adsorptive process integrates a simulated moving bed (SMB) unit with water removal and desorbent recovery systems, whereas the distillation process relies on multiple columns operating at different pressures to handle the strongly nonideal multicomponent thermodynamics. Rigorous process modeling is conducted by a combination of the Aspen Plus flowsheet simulation package and our in-house SMB modeling and optimization package, with realistic multicomponent adsorption and vapor–liquid equilibrium models parametrized by experimental data. This is followed by detailed calculations and sensitivity analysis of bare-module, utility, and material costs. The net present values (NPVs) of the process alternatives show a clear long-term economic advantage of the adsorptive process, mainly due to large reduction in utility costs. For a 100 MTD DMF plant, the ΔNPV for adsorptive separation is strongly positive (>$6M at a 10% discount rate and 15-year operation) and remains competitive over a large range of sensitivity factors. When translated to a large potential DMF biofuel market size similar to that of bioethanol, the SMB-based adsorptive process would save >$8B/yr. globally in separation costs. Furthermore, the novel adsorptive process has much better sustainability indicators, including 41% lower process energy intensity and 37% lower process CO2 emissions, as well as a number of qualitatively determined environmental and safety advantages.

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Section: Introductionsupporting

confidence: 56%

Section: ■ Introductionmentioning

confidence: 99%

Separation and Purification of 2,5-Dimethylfuran: Process Design and Comparative Technoeconomic and Sustainability Evaluation of Simulated Moving Bed Adsorption and Conventional Distillation

Chiang

Bassas

Lively

et al. 2020

ACS Sustainable Chem. Eng.

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“…The separation of xylenes on a large scale is performed by the adsorption in porous materials such as X and Y zeolites [13] or by fractional crystallization [14,15]. Current research efforts are focused on advances of new membranes and sorbents that decrease the energy consumption of such isomer separation [12].…”

Section: Introductionmentioning

confidence: 99%

Molecular simulation of the vapor-liquid equilibria of xylene mixtures: Force field performance, and Wolf vs. Ewald for electrostatic interactions

Caro-Ortiz

Hens

Zuidema

et al. 2019

Fluid Phase Equilibria

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This article explores how well vapor-liquid equilibria of pure components and binary mixtures of xylenes can be predicted using different force fields in molecular simulations. The accuracy of the Wolf method and the Ewald summation is evaluated. Monte Carlo simulations in the Gibbs ensemble are performed at conditions comparable to experimental data, using four different force fields. Similar results using the Wolf and the Ewald methods can be obtained for the prediction of densities and the phase compositions of binary mixtures. With the Wolf method, up to 50% less CPU time is used compared to the Ewald method, at the cost of accuracy and additional parameter calibration. The densities of p-xylene and m-xylene can be well estimated using the TraPPE-UA and AUA force fields. The largest differences of VLE with experiments are observed for o-xylene. The p-xylene/o-xylene binary mixtures at 6.66 and 81.3 kPa are simulated, leading to an excellent agreement in the predictions of the composition of the liquid phase compared to experiments. The composition of the vapor phase is dominated by the properties of the component with the largest mole fraction in the liquid phase. The accuracy of the predictions of the phase composition are related to the quality

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“…Separation using adsorption in porous materials is an attractive alternative to the distillation for the separation of chemicals . The use of solid adsorbents for separation yields higher separation efficiencies and lower energy consumption than traditional separation processes. , The separation of xylenes in porous materials can be achieved by adsorption zeolites such as FAU-type − and metal–organic frameworks. , Many industrial applications strongly rely on the selective hosting capabilities of zeolites. − …”

Section: Introductionmentioning

confidence: 99%

Competitive Adsorption of Xylenes at Chemical Equilibrium in Zeolites

et al. 2021

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The separation of xylenes is one of the most important processes in the petrochemical industry. In this article, the competitive adsorption from a fluid-phase mixture of xylenes in zeolites is studied. Adsorption from both vapor and liquid phases is considered. Computations of adsorption of pure xylenes and a mixture of xylenes at chemical equilibrium in several zeolite types at 250 °C are performed by Monte Carlo simulations. It is observed that shape and size selectivity entropic effects are predominant for small one-dimensional systems. Entropic effects due to the efficient arrangement of xylenes become relevant for large one-dimensional systems. For zeolites with two intersecting channels, the selectivity is determined by a competition between enthalpic and entropic effects. Such effects are related to the orientation of the methyl groups of the xylenes. m -Xylene is preferentially adsorbed if xylenes fit tightly in the intersection of the channels. If the intersection is much larger than the adsorbed molecules, p -xylene is preferentially adsorbed. This study provides insight into how the zeolite topology can influence the competitive adsorption and selectivity of xylenes at reaction conditions. Different selectivities are observed when a vapor phase is adsorbed compared to the adsorption from a liquid phase. These insight have a direct impact on the design criteria for future applications of zeolites in the industry. MRE-type and AFI-type zeolites exclusively adsorb p -xylene and o -xylene from the mixture of xylenes in the liquid phase, respectively. These zeolite types show potential to be used as high-performing molecular sieves for xylene separation and catalysis.

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The Parex Process for the Separation of p-Xylene

Cited by 5 publications

References 15 publications

Separation and Purification of 2,5-Dimethylfuran: Process Design and Comparative Technoeconomic and Sustainability Evaluation of Simulated Moving Bed Adsorption and Conventional Distillation

Separation and Purification of 2,5-Dimethylfuran: Process Design and Comparative Technoeconomic and Sustainability Evaluation of Simulated Moving Bed Adsorption and Conventional Distillation

Molecular simulation of the vapor-liquid equilibria of xylene mixtures: Force field performance, and Wolf vs. Ewald for electrostatic interactions

Competitive Adsorption of Xylenes at Chemical Equilibrium in Zeolites

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