Hydrodesulfurization Of Naphtha Research Articles

Bimetallic CoMo and trimetallic CoMoW catalyst supported on γ-Al2O3 for efficient naphtha hydrodesulfurization

Bimetallic CoMo and trimetallic CoMoW catalyst supported on γ-Al2O3 for efficient naphtha hydrodesulfurization

Selective hydrodesulfurization of FCC naphtha over carbon coated alumina supported CoMoS catalysts

Herein, carbon coated alumina (C@Al2O3) samples obtained by chemical vapor deposition of ethylene have been proposed as supports for CoMoS hydrodesulfurization (HDS) catalysts of full-range FCC naphtha. Various degree of support graphitization (from 30 to 74%) was achieved by changing the treatment time of alumina in ethylene from 15 to 120 min. The influence of the alumina graphitization on the state and morphology of the sulfide component and catalytic performance of CoMoS catalysts has been studied in detail. The dispersion of sulfide particles and the CoMoS phase content is found to increase with the growth of the graphitization degree. This is accompanied by an increase in the selectivity of the CoMoS/C@Al2O3 catalysts in the HDS of FCC naphtha, whereas the reverse trend is observed for the activity. Thus, by changing the support graphitization degree, the selectivity of CoMoS catalysts in FCC naphtha HDS can be tuned. An increase in the support graphitization degree to 74% made it possible to reduce the sulfur content in FCC naphtha from 238 to 10 ppm, with a total loss in octane number of less than 1.5 units, which demonstrates the great potential of CoMoS/C@Al2O3 catalysts for commercial application in selective HDS of FCC naphtha.

Diffusion simulation based design and macroporous structure tailored preparation of FCC naphtha selective hydrodesulfurization catalyst

Aiming at the rational design and controllable preparation of highly selective fluid catalytic cracking (FCC) naphtha hydrodesulfurization (HDS) catalyst, a two-dimensional lattice Boltzmann method with multi-relaxation-time collision operator was developed to simulate the intraparticle diffusivities in alumina supports. The simulation results showed that, in a series of virtual alumina supports with the identical mesoporous structure but different macroporous structures, which were constructed via the random generation of macro-mesopores, the intraparticle diffusivity increases sharply with the increasing macropore volume and diameter, with the one having macropore volume 0.55 cm3/g and macropore diameter 500 nm simultaneously guaranteeing both satisfactory intraparticle diffusion performance and suitable crushing strength. Based on the simulation results, five γ-Al2O3 supports with the identical mesoporous structure but different macroporous structures were synthesized from the same pseudo-boehmite precursor by using sodium polyacrylate and different amounts of water during shaping, from which five CoMo/γ-Al2O3 catalysts were prepared. The HDS assessment results obtained using a real FCC naphtha showed that, compared with the reference catalyst prepared from an alumina without macropores, the catalysts prepared from the aluminas with different macroporous structures displayed higher HDS selectivity due to the enhanced diffusion in macropores. The systematic characterization results demonstrated that the enhanced HDS activities and selectivities of the macroporous alumina supported catalysts are mainly attributed to the enhanced diffusion in macropores.

Synthesis of MoS2 quantum dots as a nanocatalyst for hydrodesulfurization of Naphtha: Experimental and DFT study

In this research, a highly active unsupported MoS2 quantum dots (M-QDs) nanocatalyst was synthesized through exfoliation and dispersion of MoS2. In this research, an easy, low-cost, high yield, and scalable method is presented and performed as a single step as a nanocatalyst for hydrodesulfurization (HDS). The catalysts were characterized by XRD, FESEM, AFM, Raman Spectroscopy, UV–vis Spectroscopy, Florescence Spectroscopy, BET-BJH, TPR, and NH3-TPD analyses. XRF spectrometry technique was used to measure the sulfur of the feed and products. The HDS reactions of M-QDs nanocatalyst were investigated under different operating parameters. The conversion of the HDS of naphtha with 2500 ppm of sulfur indicated a noticeably higher yield of unsupported M-QDs nanocatalyst (0 ppm Sulfur) as compared with the Co-Mo/γAl2O3 as a commercial catalyst which is economically valuable. DFT results revealed that the defected MoS2 structure provides a weak adsorption affinity toward hydrogen on Mo sites which could also dissociate the H2 molecules through an endothermic reaction. It can be stated that the sulfur-defected MoS2 structure is more favorable to perform the HDS reaction which can be due to activation of H2 molecules and their easier dissociation. These results were consistent with experimental data.

Design and Control of a Reactive Distillation Process for Naphtha Hydrodesulfurization

Increasingly stringent regulations on the maximum permissible sulfur levels in transportation fuels has inspired considerable interest in reactive distillation (RD) based fuel hydrodesulfurization (HDS) in the refining industry. In this work, the steady-state economic design and plantwide control of an RD naphtha HDS process is studied. The process consists of an RD column followed by an absorber-stripper unit. Engineering heuristics are employed to develop a near-optimum economic process design. The important trade-offs in the design of the process are explained. A simple decentralized plantwide control system employing single-point temperature inferential control in the RD column with the fresh naphtha feed as the throughput manipulator is shown to provide effective process regulation for large changes in throughput, fresh naphtha thiophene composition, and feed hydrogen composition.

Graphene based catalysts for deep hydrodesulfurization of naphtha and diesel fuels: A physiochemical study

In this study, graphene materials have been synthesized with solid camphor (C10H16O) and methane gas as carbon precursors using atmospheric pressure chemical vapor deposition (CVD) technique at a temperature range of 900–1000°C for a period of 45min over copper nanoparticles. Influence of the carbon precursors upon the shape, number of layers and yield of the synthesized graphene samples has been investigated. In this venue, the compounds synthesized were functionalized with oxygen groups and impregnated by cobalt and molybdenum active phases. Moreover, the total metal loading and Co/Mo weight ratio of prepared compounds were adjusted to their industrial nominal values of 10% and 0.33, respectively. The synthesized compounds were characterized through the Transmission Electron Microscopy (TEM), Raman Spectroscopy and X-ray Diffraction (XRD) techniques as well as; BET–BJH, Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared (FTIR) spectroscopy, Inductively Coupled Plasma (ICP), Temperature Programmed Reduction (TPR), and Temperature Programmed Desorption of ammonia (NH3-TPD) analyses. In terms of synthesis of graphene material, results revealed that graphene sheets with a high yield of 90% and less than 5 layers were obtained from camphor. Ultimately, the evaluations of the HDS of naphtha with 1350ppm of sulfur demonstrated a considerably higher activity of the carbonaceous based catalysts synthesized (98.5–100% S-removal) compared with the industrialalumina based catalyst (92.6% S-removal). Moreover, as a significant result, the sulfur content of the diesel feed was reduced from 13,000 to 15ppm using camphoric based catalysts at approximately mild reaction conditions (300°C, 15bar hydrogen pressure, 100NL/L H2/feed ratios, and LHSV of 5h−1).

In Situ and Simultaneous Synthesis of a Novel Graphene-Based Catalyst for Deep Hydrodesulfurization of Naphtha

In this research, a novel graphene-supported catalyst was prepared through which, a simultaneous chemical exfoliation of graphite and MoS2 powder performed preparing a new composite species and evaluated for the hydrodesulfurization reaction of naphtha and no sulfidation pretreatment was performed upon the catalyst. Also, the influences of the operating parameters such as temperature, and liquid hourly space velocity on HDS conversion evaluated.

Naphtha hydrodesulfurization over micro and nanostructure MoO3 catalysts

Highly active unsupported MoO3 and Co−MoO3 catalysts were prepared by a simple solution reaction method in the presence of different organic additives. Catalysts were characterized by the XRD, BET surface area measurement, SEM and TEM techniques. Results suggested that utilizing different additives produced different morphologies of MoO3 microstructures. Optimizing reaction conditions was found to produce more active molybdenum oxide nanoparticles when urea and PEG200 additives were utilized. XRD and TEM results indicated crystal growth restriction after cobalt incorporation. Catalytic activities of prepared materials were evaluated in the hydrodesulfurization reaction of Naphtha. Products were analyzed by XRF to determine the residual sulfur content of the feed after the reaction occurred. It was concluded that nanostructures and promoted catalysts had higher activities than microstructure samples. Ultimately, the reaction over the urea-prepared promoted catalyst decreased the sulfur content of the feed of Naphtha from 2420 to 24 ppm, which is considerably lower than that of commercial catalysts.

Advanced energy saving in the reaction section of the hydro-desulfurization process with self-heat recuperation technology

Abstract The reaction section of the naphtha hydro-desulfurization (HDS) process is a heating and cooling thermal process consisting of a feed/effluent heat exchanger and a fired heater. Energy savings are fundamentally made as a result of the maximized heat recovery in the heat exchanger and the reduced heat duty of the fired heater. To achieve further energy saving in the process, “self-heat recuperation technology” (SHRT) was adopted. In this technology, a compressor was introduced. The suction side of the compressor needed a lower pressure and the feed stream evaporated much easily. The discharged side of the compressor satisfied the operating conditions of both pressure and temperature at the inlet of the reactor. And the reactor effluent stream was able to be used completely to preheat and vaporize the feed stream. All the heat in the process stream was re-circulated without using a fired heater. SHRT was applied to the naphtha HDS process of 18,000 barrel per stream day (BPSD) in the refinery and the mass and energy balance of the process was calculated using commercially available simulation software, Invensys PROII version 8.1. This process-simulation case study confirmed that despite there being no more energy saving potential in the conventional process that makes use of a fired heater, the advanced process with SHRT can reduce the energy consumption significantly by using the recuperated heat of the feed stream.

Comparison between a conventional process and reactive distillation for naphtha hydrodesulfurization

Reactive distillation is a useful operation in which reactions and separation take place in the same unit. In this paper, the feasibility of using reactive distillation for hydrodesulfurization of naphtha is explored by simulation and experimentation. It was found that the process can be attractive since initial and operation costs are reduced substantially while the specification of the products can be met.

Technical and Economical Analysis of Hydrogen Sulfide Removal from the Recycled Hydrogen in a Diesel Hydrodesulfurization Plant

Hydrodesulfurization (HDS) is a catalytic process used to remove sulfur compounds, which leads to very low sulfur concentrations. HDS turns more complicated and severe according to the feedstock boiling range, since sulfur compounds present in light cuts, normally sulfides and mercaptanes, are easy to remove, and sulfoaromatic compounds, specially polycyclics, are the more refractive ones (Speight, J. G. (1981). The Desulfurization of Heavy Oils and Residua. 2nd ed. Marcel Dekker, Inc.: Chemical Industries 4.) The hydrogen sulfide (H2S) produced in the HDS has an inhibiting effect on the same reaction, as it has been widely observed (McCulloch, D. C. (1983). Applied Ind Catal. I:69; National Petroleum Refining Association (NPRA). (1993). Questions & Answers, 99; Leglise, J., Van Gestel, J., Duchet, J. C. (1994). Symposium on Advances in Hydrotreating Catalysts Presented before the Division of Petroleum Chemistry Inc. In: 208th National Meeting American Chemical Society. Washington D.C. p. 533). This effect is well known even at relatively low H2S concentrations (2 mol%) for commercial operation conditions (Leglise, J., Van Gestel, J., Duchet, J. C. (1994). Symposium on Advances in Hydrotreating Catalysts Presented before the Division of Petroleum Chemistry Inc. In: 208th National Meeting American Chemical Society. Washington D.C. p. 533). Due to this, the H2S removal from the recycled hydrogen to the reactor is mandatory in order to increase the desulfurization levels or to increase the processing capacity of an HDS plant. There are many options to low the H2S concentration in the H2 loop (Cooper, A., Stanislaus, A., Hannerup, P. N. (June 1993). Hyd Process 84; Johnson, A. D. (1983). Oil and Gas J 10:78; Nash, R. M. (1989). Oil and Gas J 13:47; Suchanek, A. J., Dave, D., Gupta, A., Van Stralen, H., Karlsson, K. (1993). In: NPRA Annual Meeting AM-93-24; Tippett, T., Knudsen, K. G. (1999). In: NPRA Annual Meeting. San Antonio, TX. 1999 NPRA Annual Meeting, San Antonio, TX, AM-99-06.), which are from a simple purge adjustment for light naphtha HDS to a full treatment of the H2 stream for middle distillate HDS, where the H2S concentration can reach levels of 10 mol% (National Petroleum Refining Association (NPRA). (1993). Questions & Answers, 99). This work presents the economical analysis of the introduction of an Amine Treating Unit in an HDS plant in operation to remove H2S from the H2 stream recycled to the reactor.

95/03581 Simulated distillation and mathematical description of coal tar

Reactive distillation is a useful operation in which reactions and separation take place in the same unit. In this paper, the feasibility of using reactive distillation for hydrodesulfurization of naphtha is explored by simulation and experimentation. It was found that the process can be attractive since initial and operation costs are reduced substantially while the specification of the products can be met.

ナフサの水素添加脱硫

ナフサの水素添加脱硫