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Internship report: study of regeneration and rejuvenation of Pt-Re-In/Al2O3 naphtha reforming catalysts

Report of ENSCL first-year’s internship performed at INCAPE under the supervision of PhD Carlos PIECK from July 4th to August 17th 2012.

ENSCL – Ecole Nationale Supérieure de Chimie de Lille – National Chemistry School of Lille Cité Scientifique Avenue Dimitri Mendeleïev 59652 - VILLENEUVE D’ASCQ France http://www.ensc-lille.fr/

INCAPE – Instituto de Investigaciones en Catálisis y Petroquímica – Catalysis and Petrochemistry Research Institute Santiago del Estero 2654 3000 - SANTA FE Argentina http://www.fiq.unl.edu.ar/incape/

DAVID Charles Chemical engineering student at ENSCL


acknowledgements// I would like to thank the whole team of Laboratory 59 of INCAPE, especially Dr. Carlos Pieck for his patience and the great knowledge transmission which would not have taken place if it wasn’t for all his experience. Thanks as well to Ana Vicerich for her help while performing all experimental work and for ceding laboratory’s equipment and therefore putting off her own manipulations. My thanks to family Hernandez, especially to Emiliano, for housing me at their house and introducing me Argentina and the Argentinian culture with criticism. Thanks to Alicia for preparing the Mate every morning and taking care of us.


abstract// Performance of gasoline is directly connected to its octane rating. In order to transform ordinary naphthas into high octane gasolines, a reaction called naphtha reforming has to take place. This process generally employs Pt-Re/Al2O3 catalysts, but researches on trimellatic catalysts are being carried out in order to improve reaction products. This report describes an internship where the student worked on preparation, simulation of sintering, rejuvenation and test reactions (chemisorption of CO, dehydrogenation of cyclohexane, hydrogenolysis of cyclopentane and reforming of n-heptane) using Pt-Re-In/Al2O3 naphtha reforming catalyst, helping in a current study of a research team at INCAPE, in Santa Fe, Argentina. Internship lasted 6 weeks and some results were obtained, but their analysis could not be completed. PtRe-In/Al2O3 presented high dispersion and high cyclohexane conversion after simulation of sintering and low cyclopentane conversion after rejuvenation, which shows that it does not behave like other trimetallic naphtha reforming catalysts. The internship met student’s expectations and it will surely be an important factor for future decisions. Cultural exchange and a great improvement of the student’s Spanish level must also be highlighted. Keywords: naphtha reforming catalysts, Pt-Re-In/Al2O3, sintering, rejuvenation, chemisorption of CO, dehydrogenation of cyclohexane, hydrogenolysis of cyclopentane, reforming of nheptane, INCAPE.


résumé// La performance d’une essence est directement liée à son indice d’octane. Afin de transformer des naphtas ordinaux en des essences à haut indice d’octane, une réaction appelée reformage d’essence doit avoir lieu. Ce processus utilise généralement des catalyseurs Pt-Re/Al2O3, mais des recherches sur des catalyseurs trimétalliques sont également menées de façon à améliorer les produits de réaction. Ce rapport décrit un stage où l’étudiant a réalisé la préparation, la simulation de frittage, le rajeunissement et des réactions-test (chimisorption de CO, déshydrogénation de cyclohexane, hydrogénolyse de cyclopentane et reformage de n-heptane) avec le catalyseur Pt-Re-In/Al2O3, dans le cadre d’une étude menée par un groupe de recherche de l’INCAPE, à Santa Fe, Argentine. Le stage a duré 6 semaines et quelques résultats ont été obtenus, cependant leurs analyses n’ont pas pu être effectuées. Pt-Re-In/Al2O3 a présenté une grande dispersion et une haute conversion de cyclohexane après l’étape de simulation de frittage et une basse conversion de cyclopentane après le rajeunissement, ce qui montre que ce catalyseur ne se comporte pas de la même façon que d’autres catalyeurs trimétalliques de reformage d’essence. Ce stage a répondu aux attentes de l’étudiant et sera sûrement un facteur important pour de futures décisions. Un échange culturel et une importante amélioration du niveau d’espagnol de l’étudiant doivent aussi être soulignés. Mots-clés: catalyseurs de reformage d’essence, Pt-Re-In/Al2O3, frittage, rajeunissement, chimisorption de CO, déshydrogénation de cyclohexane, hydrogénolyse de cyclopentane, reformage de n-heptane, INCAPE.


contents// Abstract RĂŠsumĂŠ Contents 1 Presentation of INCAPE ....................................................................................................................... 1 2 Introduction and context...................................................................................................................... 3 2.1 Engine-knocking and octane rating ................................................................................................. 3 2.2 Naphtha and its reforming process ................................................................................................. 4 2.3 Naphtha reforming catalysts .......................................................................................................... 6 3 Practical work and discussion ............................................................................................................. 10 3.1 Catalyst preparation ..................................................................................................................... 10 3.2 Simulation of catalyst sintering ..................................................................................................... 10 3.3 Catalyst rejuvenation.................................................................................................................... 11 3.4 Chemisorption of CO .................................................................................................................... 11 3.5 Dehydrogenation of cyclohexane (DCH) ....................................................................................... 13 3.6 Hydrogenolysis of cyclopentane (HCP).......................................................................................... 14 3.7 Reforming of n-heptane (n-C7)...................................................................................................... 14 3.8 Discussion .................................................................................................................................... 15 4 Hygiene and safety ............................................................................................................................. 16 5 Personal and professional contribution.............................................................................................. 17 6 Conclusion .......................................................................................................................................... 18 7 References.......................................................................................................................................... 19 Annexes


1 presentation of INCAPE// The INCAPE – Instituto de Investigaciones en Catálisis y Petroquímica – Catalysis and Petrochemistry Research Institute, is basically a catalysis Argentinian public research institute that works on catalysts for the petrochemical industry but also for other fields. In 1957 the Argentinian government created the CONICET – Consejo Nacional de Investigaciones Científicas y Técnicas – National Council of Scientific and Technical Research, which stimulated the education of new researchers in Argentina. Some years later, when the first researchers were ready with their formation process, CONICET implemented a subsidy system for the purchase of instruments in order to create the first laboratory for determination of physical properties of catalysts in a Latin American university. This laboratory was installed at the FIQ – Facultad de Ingeniería Química – Chemical Engineering College of the UNL – Universidad Nacional del Litoral – National University of Litoral, in the city of Santa Fe. Researches in several areas of chemical reactions and unit operations were carried out and, as the staff and subjects were complemented, these started to be more focused on heterogenic catalysis. In order to have a better organization and make possible for the number of researches to increase, FIQ created in 1969 the Institute of Catalysis. At that time, Argentina was undergoing a very important industrial growth process, new petrochemical plants were being established and some important products for modern societies’ lifestyle started to be produced there, such as detergents, artificial fibers, plastics, insecticides and solvents. This was the reason for a great interest for catalysis, since 95% of the chemical reactions involved in petrochemistry need catalysts. Also some other important products of the chemical industry as sulfuric acid, nitric acid, alcohols, aldehydes and ketones need catalysts. Given the importance of the petrochemical industry in Argentina in the 70’s, in the year 1978 the Institute of Catalysis becomes the actual Catalysis and Petrochemistry Research Institute – INCAPE. Today INCAPE’s laboratories are located in two different buildings, both in the center of Santa Fe. In these laboratories various different analysis are possible, such as atomic emission spectroscopy with inductively coupled plasma (ICP-AES), XRD, gas chromatography, mass spectroscopy, differential thermal analysis (DTA), differential scanning calorimetry (DSC), thermogravimetric analysis, temperature-programmed desorption / reduction / oxydation (TPD / TPR / TPO), raman spectroscopy, etc [1].

One important aspect of INCAPE is that it has a pilot plant, so that when the research projects should reach the industrial scale, some tests in the pilot scale are carried out. This pilot plant is equipped with a distillation tower with sampling in every dish, gas-liquid and liquidliquid contact towers, spray, rotating and dish dryers, heat exchangers, pumps, etc, which are also used for practical classes for students of the FIQ - UNL. 1


INCAPE’s researches are divided into six different fields: -

Oil refining processes and petrochemistry Biomass resources valorization Removal of contaminants from liquid and gaseous effluents Catalytic processes in fine chemistry Chemical and catalytic reactors New materials

This internship was performed at INCAPE’s Laboratory 59, where a team of 6 people works in the oil refining processes and petrochemistry field. This team is directed by Dr. Carlos Pieck. Viviana Benitez, PhD in chemistry, works on preparation and characterization of superacid catalysts for isomerization and cracking of short and long paraffins and on noble metal catalysts for naphtha reforming. Silvana D’Ippolito, PhD in chemical engineering, works on the preparation, characterization and regeneration of trimetallic catalysts for naphtha reforming and selective ring opening. Vanina Mazzieri, PhD in chemistry, works on preparation and characterization of multimetallic catalysts for naphtha reforming and on metal-supported catalysts for selective hydrogenation of esters into fatty alcohols. Amparo Sanchez, PhD student in chemical engineering, writes a thesis on selective hydrogenation of methylic esters of fatty acids into fatty alcohols. Ana Vicerich, PhD student in chemical engineering, writes a thesis on selective opening of rings to ameliorate the cetane rating of diesels. Vicerich helped the intern and gave practical instruction about using the equipment. Dr. Carlos Pieck, PhD in chemistry by the French university of Poitiers, performed a research internship in Sapporto, Japan, and a post-doctoral internship at the Institute of Catalysis and Petrochemistry of Madrid, Spain. He works on catalysts for naphtha reforming and has already published 87 works on international research magazines and presented 144 works in international congresses. Dr. Pieck supervised the intern all along the internship, explaining catalytic reforming, test reactions and giving important theoretical information.

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2 introduction and context// 2.1 engine-knocking and octane rating/ A very important property of gasoline is its resistance to knocking and detonation during operation of an internal combustion engine. Knocking occurs when the combustion of the airfuel mixture in the cylinder doesn’t start in response to ignition by the spark plug, but by a precipitate spontaneous explosion during compression. Given that the more the mixture is able to be compressed in the cylinder without exploding, the greater the power that the engine is able to deliver, such a desynchronization of the engine results in a loss of power and in greater fuel consumption. The anti-knocking property of gasolines is usually expressed by their octane numbers. A gasoline with a high octane number will allow a correct operation of the engine without vibrations or unwanted explosions. Chemical compounds that provide high octane numbers are branched paraffins and aromatics [2]. The combustion reactions of these hydrocarbons have greater activation energies ( ) than those of straight-chain paraffins with similar number of carbon atoms, which means that more energy is demanded for their combustion to start, making it more difficult for the mixture to explode spontaneously. When transforming a straight-chain paraffin into a branched paraffin or aromatic with same number of carbon atoms, an eventual reduction in the combustion energy is not prejudicial for the power of the engine because what counts is the amount of gas produced during the combustion, since the gas is what pushes the piston down the cylinder. The octane number of a gasoline corresponds to the percentage by volume of i-octane (2,2,4-trimethylpentane) in a blend with n-heptane that matches this gasoline in knocking characteristics in a standard engine run under standard conditions. In this way, a gasoline that presents the same knocking characteristics that a 90%/10% volume i-octane/n-heptane mixture will have an octane number of 90. A set of conditions produces the research octane number (RON, indicative of normal road performance) and a more severe set of conditions gives the motor octane number (MON, indicative of high-speed performance). The arithmetic average of these two values, known as , is being increasingly used. Annex 1 gives the research octane numbers of some hydrocarbons. In 1922, it was discovered that tetraethyl lead is an excellent anti-knocking substance when added to gasoline in small quantities. This compound has then been used for a long time to increase gasolines’ octane numbers. However, many countries have changed their legislation in the 80’s and 90’s in order to reduce the amount of lead in gasoline because of its negative effects on population’s health. The addition of lead was compensated by increasing the severity of the reforming process (increase in aromatic concentration) as well as adding oxygenated compounds (ethers, alcohols, MTBE and TAME). In order to decrease even more the harmful 3


vehicle emissions, the maximum concentration of benzene has been limited in several countries. This evolution of countries’ legislation about gasoline forced industrials to improve their reforming methods in order to respect all requirements without reducing their gasoline’s performance [2].

2.2 naphtha and its reforming process/ Naphtha is the fraction of the petroleum distillation process that contains hydrocarbons having boiling points ranging from 30°C to 200°C and 5 to 12 carbon atoms [3]. Annex 2 gives the weight distribution of an ordinary straight-run naphtha. As it can be seen, some linear paraffins, specially n-heptane, n-octane and n-nonane, are present in important amounts. These three compounds together correspond to 15,4% of the total weight of the naphtha in question. In order to obtain gasolines with high octane numbers, it is necessary to transform them into branched paraffins or aromatics. This process is called naphtha reforming and is carried out in petroleum refineries by a metal-acid-catalyzed reaction. Catalytic reforming occurs at high temperatures (450-520°C) and moderate pressure (430 bar). Using a proper catalyst in three or four serial reactors and in presence of hydrogen (H2/hydrocarbons equal to 4-6 mol/mol), naphthenes are transformed into aromatics by dehydrogenation and straight-chain paraffins into branched paraffins by isomerization. Paraffins also form aromatics by dehydrocyclization. Other important reactions are hydrogenolysis and hydrocracking (carbon–carbon bond scissions), which result in low molecular weight paraffins, and coke formation that will eventually deactivate the catalyst. Figure 1 shows the major reforming reactions [3].

Figure 1 Major reactions in catalytic reforming of naphtha. [3] Nearly all naphtha reforming methods use 3 or 4 serial reactors because these reactions are globally endothermic and such a scheme allows heating the reformate between each reformer. Reactions (e) and (f) are undesired in the naphtha reforming process because they 4


produce, respectively, low molecular weight hydrocarbons and coke. Hydrocarbons having from 1 to 4 carbon atoms should not be produced because they are not gasoline components and have a low market value. The formation of coke is also very prejudicial to the reforming process because it deactivates the catalyst by deposition. Coke is a solid substance composed mainly by polyaromatic rings which production is favored under low pressures and cannot be completely avoided. Reformers must thereby be regularly regenerated, so that the catalyst’s activity is recuperated. A simple replacement of deactivated catalyst by a new one is not industrially viable because of the price of the fresh catalyst. The regeneration of the reforming catalysts is usually performed by passing a controlled flow of oxygen and burning the deposited coke. The temperature of this combustion must be mastered because metal sintering occurs at high temperatures (usually above 450°C) [4]. Sintering is a phenomenon where atoms of the metallic phase of the catalyst get closer one to another, forming agglomerates. This process reduces the activity of the catalyst, since its activity is function of the number of exposed metallic atoms. After the regeneration, the catalyst must be rejuvenated. The object of the rejuvenation step is to return the reforming catalyst to a state as close as possible to the fresh one. This means that after burning the carbon from the catalyst it will be necessary to restore metals to their reduced form, high metal dispersion levels, and the proper level of acid function by controlled injection of chloride compounds. In order to achieve these goals, the general steps to follow are redispersion, reduction and sulfidation [5]. At the industrial scale, the following rejuvenation protocol is usually employed: 1. Nitrogen carrier gas is passed over the catalyst up to 200°C to remove any adsorbed hydrocarbons. 2. A well-controlled concentration between 0,5 and 2,0% oxygen in nitrogen carrier gas is passed over the catalyst bed with ramped heating up to 500°C. 3. Chlorine addition to the system under an air atmosphere at 500°C during oxidation is practiced to redisperse the metal crystallites [6]. Reforming plant schemes are divided basically into three different groups according to their regeneration method: semiregenerative process, cyclic (fully regenerative) process and continuous regenerative (moving bed) process [7]. Semiregenerative Process: this process is characterized by a continuous operation of reactors over long periods, with decreasing catalyst activity. Eventually the reformers are shut down as a result of coke deposition to regenerate the catalyst in situ. Regeneration is carried out at low pressure (approximately 8 bar) with air as source of oxygen. This process is a conventional reforming process which operates continuously over a period up to 1 year. At the end of this period, reformers operation must be completely interrupted in order to regenerate the catalyst. RON that can be achieved in this process is usually in the range of 85-100. UOP, IFP, Exxon, Chevron and Houdry have licensed naphtha reforming methods using this process. 5


Cyclic (Fully Regenerative) Process: this process uses five or six reactors, similar to the semiregenerative process, with one additional swing reactor, which is a spare reactor. It can substitute any of the regular reactors while one of them is being regenerated. In this way, only one reformer at a time must be taken out of operation. Since reforming in these reactors is carried out at low pressures, catalyst of an individual reactor becomes deactivated after a period of 1 week to 1 month. The cyclic process allows transforming naphtha to a gasoline having a RON range of 100-104. Exxon and Amoco have licensed naphtha reforming methods using this process. Continuous Regenerative (Moving Bed) Process: in this process, small quantities of catalyst are continuously withdrawn from an operating reactor, transported to a regeneration unit, regenerated, and returned back to the reactor. In the most common moving-bed reactors system, all reactors are positioned one on the top of the other. A range of 95-108 RON can be obtained. UOP and IFP have licensed naphtha reforming methods using this process.

2.3 naphtha reforming catalysts/ Catalyst for the desired reforming reactions must have two types of function: a hydrogenation-dehydrogenation function (metals from Group VIII of the Periodic Table) and a cyclization or isomerization function. The last function is provided by oxides with acid properties. In 1949, the first bifunctional metal-acid catalyst was introduced in this process and had platinum as metallic function [8]. The addition of rhenium to promote platinum’s activity was patented in 1968, opening the era of bimetallic catalysts [9]. Bimetallic catalysts are more stable than the monometallic ones, producing less coke and allowing reforming at lower pressures with better selectivity to aromatics and a better liquid yield. Some of the first catalysts had silica-alumina or fluorine-promoted alumina as the acid function, but these strong-acid substances produced too much cracking, leading to low molecular weight paraffins. The acid function of present reforming catalysts is ensured by chloride-promoted alumina, which is more selective for isomerization reactions and its acidity can be easily regulated by a change in the chloride concentration. These catalysts contain about 0,2-0,4wt% platinum as metal function with one or more metals as modifiers, such as rhenium, tin, germanium or iridium. This metal function is supported on the acid function, which is alumina with acidity promoted by nearly 1% chloride [10]. The addition of Re to Pt gently reduces metal’s capability of catalyzing dehydrogenation and increases notably hydrogenolysis, as respectively shown by dehydrogenation of cyclohexane in Figure 2 and hydrogenolysis of cyclopentane in Figure 3. The augmentation of hydrogenolysis is corrected in industry by passivation of the catalyst with sulfur, since it produces low-weight hydrocarbons which are not desired in naphtha reforming. Current theories about the modification of Pt monometallic catalysts by addition of a second metal are based on electronic and/or geometrical considerations. The modification of Pt electronic properties leads to significant changes in adsorption energies of chemisorbed hydrocarbons so 6


activity and selectivity are affected. This may be the reason for a diminution on catalyst deactivation by coking in Pt-Re/Al2O3 [10]. On the other hand, the main reactions of catalytic reforming have different structure sensitivity that depends on purely geometric factors. It is well known that de/hydrogenation reactions can proceed on simple (monoatomic) sites, but hydrogenolysis and coking require catalytic sites of a more complicated morphology (clusters or ensembles) [11-13]. The addition of a second inactive metal (Sn, Ge) to the catalyst places ‘‘spacers’’ between Pt groups and reduces the effective size of the catalytically active Pt ensemble, modifying hydrogenolysis and coking processes and improving the catalyst performance. Pioneering works of Boudart on structure sensitivity [14,15] classified catalytic reactions as ‘‘demanding’’ (sensitive to morphological structure) and ‘‘facile’’ (structure-insensitive), according to the requirement or not of a particular ensemble of neighboring metal atoms in order to form adsorbate bonds with the proper strength.

Figure 2 Relative conversion of cyclohexane for the bimetallic catalysts as a function of second metal loading. [10] Figure 3 Relative conversion of cyclopentane for the bimetallic catalysts as a function of second metal loading. [10] Since the dehydrogenation activity drops with adding of Re, in the naphtha reforming process Pt-Re/Al2O3 produces less olefins – which are coke precursors – than Pt/Al2O3. This is the greatest quality of this bimetallic catalyst when comparing to the monometallic one, because it allows reformers to work under lower pressures and for longer periods without 7


regenerating the catalytic bed. It is true that a reduction in the olefins production could affect the formation of aromatics, but since the reaction that transforms olefins into aromatics is faster than the one that transforms olefins into coke, the generation of aromatics is not concerned. More than that, the production of aromatics increases, since Pt-Re/Al2O3 allows working at lower pressures than Pt/Al2O3, and its structure makes it more difficult for coke to depose itself over the metallic phase. Pt-Re/Al2O3 is, as shown above, a very good catalyst for industrial naphtha reforming, but it still has two negative characteristics which made industrials try to ameliorate it. The first point is that Pt-Re/Al2O3 must be passivated with sulfur before starting the reforming process in order to reduce hydrogenolysis. The quantity of sulfur must be very precise because too few sulfur is not enough to cover all Re atoms and too much injures catalyst’s activity because of the bonds which are formed between Pt and S. In addition to that, the passivation precludes the utilization of the continuous regenerative or moving bed reforming process. The second point is that Pt-Re/Al2O3 produces remarkable quantities of benzene. Benzene has a RON of 99 [2], making of it a compound that increases gasoline’s global RON. But as already told before in this work, legislation has changed and governments want to reduce its concentration in gasoline because of its carcinogenic effects on humans. In order to solve both of these problems, some patents suggest the use of trimetallic supported catalysts [16,17]. Benitez and Pieck, from INCAPE, presented a work at the 15th Brazilian Catalysis Congress, showing some results on fresh Pt-Re-In/Al2O3 catalyst [18]. They used some test reactions and characterization techniques to describe the behavior of Pt(0.3wt%)-Re(0.3wt%)-In(0.1 & 0.3wt%)/Al2O3 – hereafter referred to as PtReIn(0.1) and PtReIn(0.3). These techniques are: temperature-programmed desorption of pyridine (TPD), temperature-programmed reduction (TPR), hydrogenolysis of cyclopentane (HCP), dehydrogenation of cyclohexane (DCH), isomerization of n-pentane, reforming of n-heptane and temperature-programmed oxidation (TPO). Results show that the addition of In reduces acidity and dehydrogenation and hydrogenolytic activities. Isomerization of n-C5 shows that In reduces total catalyst activity and increases the selectivity to C 5 isomers, while selectivity to low value products (C1 and C3) is reduced. Briefly, In increases the stability of Pt-Re/Al2O3 catalyst. The reforming of n-C7 shows that In increases the stability and selectivity to aromatics, reducing the production of gases and n-C7 isomers. As shown in Figure 4, In reduces coke formation, because activity of catalyst containing an important amount of In remains high while other catalysts’ activities drop notably. In 2012, in the same laboratory of INCAPE where these tests were carried out, Vicerich started doing the same test reactions on Pt-Re-In/Al2O3, but this time by simulating sintering before testing. This study aims to characterize Pt-Re-In/Al2O3 after the regeneration process in refineries, where the high temperature of combustion sinterizes the metallic phase, as explained on page 5. 8


Figure 4 Conversion of n-C7 X time. Catalyst with and without In.[18]

The internship which this report is related to aimed to give continuation to the above-mentioned tests and also to effectuate them with the rejuvenated catalysts. Catalysts were prepared, sintered and rejuvenated by the intern and the following test reactions were carried out: chemisorption of CO, hydrogenolysis of cyclopentane (HCP), dehydrogenation of cyclohexane (DCH) and reforming of n-C7. All these procedures are explained in the chapter that follows and their results are commented. Results are not deeply analyzed because the intern does not have enough background on reforming catalysis phenomena and they only represent a part of the whole study.

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3 practical work and discussion// The internship consisted in understanding and performing test reactions in order to evaluate the behavior of Pt-Re-In/Al2O3 regenerated (sintered) and rejuvenated catalysts. These tests are a part of a work that is being carried out at INCAPE which aims to analyze the effect of addition of In to Pt-Re/Al2O3 naphtha reforming catalyst. In order to make all tests possible, catalysts preparation, simulation of sintering and rejuvenation were also executed. It is important to underline that test reactions are not always the same that are carried out in refineries, but are reactions that search to characterize the behavior of a catalyst. At the beginning of the internship, the intern read books and papers, which are mentioned in the references of this report, with the aim of understanding the reforming process, reforming catalysts and their behavior. Then intern carried out the following experiments:

3.1 catalyst preparation/ Fresh catalyst was prepared in order to have enough samples to carry out all test reactions. At first, alumina is grinded using a mortar. Particles should not be too small in order to avoid charge losses in reactors neither too big in order to make the impregnation easier. Granulation must then be controlled using two sieves, one having 35 threads per inch (35 Mesh), and another having 80 threads per inch (80 Mesh). Only particles staying between these two sieves are withheld. Alumina can then be calcinated at 500째C for 4 hours. Once calcination is completed, impregnation is effectuated. Acid impregnation is carried out using a 0.2 M HCl solution in order to obtain a uniform Pt profile inside the alumina particle. Pt is impregnated using a 7.532 gPt/L H2PtCl6 solution, Re using a 20.18 gRe/L NH4ReO4 solution and In using a 4.1 gIn/L In(NO3)3 solution. The volume of each solution that must be added to alumina is calculated according to the percentage of each component in the desired catalyst. All solutions are added to alumina at the same time and impregnation lasts 1 hour. Water excess is then evaporated using a water bath and drying is carried out in stove. Mixture is calcinated for 4 hours at 450째C and reduced by H 2 at 500째C for 4 hours as well. Fresh catalyst preparation is completed. During this internship, the intern prepared Pt(0.3wt%)Re(0.3wt%)In(0.1wt%)/Al 2O3 and Pt(0.3wt%)Re(0.3wt%)In(0.3wt%)/Al2O3 (refered to as PtReIn(0.1) and PtReIn(0.3)).

3.2 simulation of catalyst sintering/ Sintering is a phenomenon that occurs during catalyst regeneration in refineries (cf. page 5) because of the heat generated during coke combustion. At the laboratory scale, 10


sintering is achieved by heating catalysts in muffle under air atmosphere. During this internship PtReIn(0.1) and PtReIn(0.3) were both sintered at 550 and 650°C.

3.3 catalyst rejuvenation/ Catalyst rejuvenation is a process that aims to recuperate as much as possible of the activity of the catalyst (cf. page 5). In this internship, rejuvenation was achieved by oxychlorination using the same method than Pieck et al used in their work “SinteringRedispersion of Pt-Re/Al2O3 during Regeneration” [19], except for the pressure, that in the work was 3 atm and during this internship was 1 atm. Reactant for oxychlorination is prepared using methanol and trichloroethylene. The proportion of each one of these compounds is calculated in order to have a H 2O/Cl atomic ratio of 20 at the products. The following reactions take place during oxychlorination of the catalyst:

Catalyst is introduced in a glass reactor and heated to 482°C under a 40 cm 3/min air flow. Once temperature is stabilized, air flow is maintained for 30 minutes. Reactant mixture then begins to be injected with a 0.21 cm3/h flow, maintaining air flow and temperature. After 3 hours, reactant injection is turned off, air flow is maintained for 30 minutes at the same temperature. Heating is then cut off, air flow is maintained while cooling down. Rejuvenation is completed. During this internship, the intern carried out rejuvenation of PtReIn(0.3) and PtReIn(0.1) sintered at 650°C.

3.4 chemisorption of CO/ ⁄ The dispersion of a metal corresponds to ratio, where Mesurf is the number of atoms on surface and Metot is the total number of metal atoms of the sample determined by a simple chemical analysis. The activity of a catalyst depends on its dispersion, since only surficial metal atoms are able to catalyze the reactions. The most common method to determinate the number of metal atoms on surface is the selective chemisorption of gases [20,21]. It consists in measuring a volume of adsorbed gas that covers a metal by a monolayer. Gas chemisorption is irreversible, fast and usually of monolayer type. A simple stoichiometry is required to correlate the number of adsorbed gas molecules to the number of superficial atoms. It can be performed with H2, O2 or CO, which are able to bond with metals [22]. Chemisorptions performed during this internship were accomplished using a pulse equipment which scheme is shown in Figure 5. Catalysts samples (~200 mg) are reduced in H2 flow (20 cm3/min) at 500°C during 1 hour. N2 is then passed in reactor (20 cm3/min) at 500°C 11


during 1 hour to eliminate chemisorbed H2 and catalysts are finally cooled down to room temperature under N2 flow. The chemisorption of CO is then executed. Injections of 0.25cm 3 of a 3.5% CO in N2 mixture are effectuated. The CO that is not chemisorbed goes out of the reactor and is transformed into CH4 in a methanator using Ni/Kieselguhr catalyst under 380°C. Methanator is fed with H2 and 100% of CO coming out of the reactor is transformed into methane and detected by a FID (Flame Ionization Detector) system in the chromatograph. All reactions occur at 1 atm. The amount of chemisorbed CO is calculated by comparing adsorbed pulses and pulses after saturation. Catalyst is considered saturated in CO when changes in chromatogram areas are no longer detected. N2 may contain traces of O2 as a result of its production process. These traces must be eliminated because O2 would chemisorb on the catalyst that is being analyzed, distorting the results. In order to do so, during the experiment N2 passes constantly through a reactor containing Mn/Celite©, which at room temperature reacts with O2 giving Mn oxides. Before each experiment, these oxides must be reduced so that the deoxygenating capability of this reactor is recuperated. This reduction occurs at 500°C and 1 atm during 1 hour.

Figure 5 Layout of the CO chemisorption equipment. Annex 3 gives an example of chemisorption chromatogram obtained during the internship. Table 1 shows results of dispersion of some catalysts: Table 1 Dispersions of analyzed catalysts Experiment

Catalyst

Dispersion (%)

4913

PtReIn(0.1) fresh

58

4902

PtReIn(0.3) fresh

67

4929

PtReIn(0.3) fresh

53 continued 12


Experiment

Catalyst

Dispersion (%)

4884

PtReIn(0.1) sintered at 550°C

64

4903

PtReIn(0.1) sintered at 650°C

38

4895

PtReIn(0.3) sintered at 650°C

53

4905

PtReIn(0.3) sintered at 650°C

50

4908

PtReIn(0.3) sintered at 650°C

43

4900R

PtReIn(0.3) sintered at 650°C and rejuvenated

45

4907

PtReIn(0.3) sintered at 650°C and rejuvenated

39

3.5 dehydrogenation of cyclohexane (DCH)/ This test reaction allows evaluating the metallic phase of a catalyst. DCH is function of the number of exposed metal atoms and not of the size of crystals, which means that this is a facile reaction (cf. page 7). Catalyst sample (~50 mg) is introduced in a glass reactor and reduced at 500°C, 1 atm, in H2 flow (36 cm3/min) during 1 hour. Then reaction takes place at 300°C and 1 atm. H 2 flow during reaction is also 36 cm3/min and cyclohexane flow is 0.73 cm3/h. A sampling valve connects the reactor to a gas chromatograph equipped with a ZB-1 capillary column having 60 m of length and 0.25 mm of diameter. Temperatures of injection, column and detector are, respectively, 200°C, 70°C and 150°C. Injections are effectuated every 5 minutes during 1 hour. A syringe pump is used to control the flow of cyclohexane, which means that cyclohexane is placed in a syringe and the pump presses the piston of the syringe with a constant speed so the flow is known. Figure 6 shows the scheme of the system used in this reaction but also in hydrogenolysis of cyclopentane (HCP) and reforming of n-C7. Table 2 gives results on performed DCH.

Figure 6 Layout of the DCH, HCP and reforming of n-C7 equipment. 13


Table 2 Average cyclohexane conversion of analyzed catalysts (300°C, 1 atm) Experiment

Catalyst

Conversion (%)

4949

PtReIn(0.1) sintered at 550°C

37

4960

PtReIn(0.1) sintered at 650°C

2

4952

PtReIn(0.3) sintered at 550°C

29

4916

PtReIn(0.3) sintered at 650°C

32

4896

PtReIn(0.3) sintered at 650°C and rejuvenated

17

3.6 hydrogenolysis of cyclopentane (HCP)/ HCP is a demanding test reaction (cf. page 7). This means that in order to take place it needs a group of metal atoms with a certain configuration. Since the 5-atom cycle can only be broken once adsorbed over contiguous sites of catalyst, very dispersed crystals present low hydrogenolysis activity while big crystals are more active [23]. Catalyst sample (~150 mg) is introduced in a glass reactor and reduced at 500°C, 1 atm, in H2 flow (36 cm3/min) during 1 hour. Then reaction takes place at 350°C and 1 atm. H 2 flow during reaction is also 36 cm3/min and cyclopentane flow is 0.48 cm3/h. A sampling valve connects the reactor to a gas chromatograph equipped with a ZB-1 capillary column having 60 m of length and 0.25 mm of diameter. Temperatures of injection, column and detector are, respectively, 150°C, 40°C and 200°C. Injections are effectuated every 30 minutes during 2 hours. This reaction uses the same equipment than DCH. Table 3 gives result on performed HCP:

Table 3 Cyclopentane initial conversion of analyzed catalyst (350°C, 1 atm) Experiment

Catalyst

Conversion (%)

4941

PtReIn(0.1) fresh

8.90

4942

PtReIn(0.3) fresh

4.51

4970

PtReIn(0.1) sintered at 550°C

16.00

4971

PtReIn(0.1) sintered at 650°C

3.03

4976

PtReIn(0.3) sintered at 550°C

1.95

4979

PtReIn(0.3) sintered at 650°C

1.87

4899

PtReIn(0.3) sintered at 650°C and rejuvenated

1.32

14


3.7 reforming of n-heptane (n-C7)/ Reforming of n-C7 is a model reaction in the naphtha reforming process. It produces toluene, n-C7 isomers and paraffins. Fung et al [24] and Clem [25] have stated that in reforming of n-C7 5-atom naphtenes are produced, which are the most important coke precursors when using an unsulfured Pt-Re/Al2O3 catalyst. Therefore, this test reaction is not only used to evaluate activity and selectivity of catalysts, but also their deactivation by coking. In the laboratory, catalyst is first reduced by a 36 cm 3/min H2 flow during 1 hour at 500°C and 1 atm. Using the same equipment than in HCP and DCH (cf. page 13), n-heptane is then injected with a 0.73 cm3/h flow. H2 flow remains the same as well as the temperature and pressure. Injections are effectuated every hour. 4 injections are made, totalizing 4 hours of experiment. This test reaction was applied on PtReIn(0.3) sintered at 650°C and PtReIn(0.3) sintered at 650°C and rejuvenated catalysts. Chromatograms were not analyzed.

3.8 discussion/ Procedures described in this chapter were not carried out in this order. First some test reactions were performed using already prepared catalyst, than some simulations of sintering were carried out and other test reactions were accomplished. Results were briefly analyzed with the intern’s supervisor and some of them were different from what was expected, especially dispersion of sintered catalysts which were higher than dispersion of fresh ones. Since DCH conversion was also high for a sintered catalyst, and chromatogram peaks for reforming of n-C7 showed a great conversion as well, it was decided to start catalyst preparation and sintering over again, in order to eliminate the possibility of error coming from sintering. Sinterings lasting 8 hours using new prepared catalysts were accomplished. Even if a slight difference in results was observed – which is probably due to the fact that the first catalysts were prepared in April and that they were sintered when atmospheric humidity was at 25% -, they were considered as confirming the first ones. Results cannot be analyzed yet, since more tests like temperature-programmed oxidation (TPO) of the coked catalysts on n-C7 reforming reaction, temperature-programmed desorption of pyridine (TPD), temperature-programmed reduction (TPR) and transmission electron microscopy (TEM) should be carried out first. But what could be said, though, is that these results, which are not in accord with usual trimetallic reforming catalysts containing Pt and Re, is that In may behave differently from other metals. During sintering, In could possibly slip off from the metallic phase, leaving Pt and Re alone, which would explain a high catalyst dispersion even after sintering at 650°C for 8 hours. This hypothesis must be confirmed by transmission electron microscopy (TEM). Other hypothesis is the elimination of In during the sintering step by volatilization. This hypothesis must be confirmed by atomic emission spectroscopy (ICP-AES). 15


4 hygiene and safety// This internship required the adoption of some important precaution, since the preparation and reactions with catalysts involve some dangerous elements. The first thing to be underlined is that the intern was always supervised by an experimented user of the laboratory in order to avoid accidents. INCAPE is an institute that has several laboratories, and there is a network of gases tabulation connecting them. These gases are hydrogen, nitrogen and air, all of them under 5 atm. When these gases are not being used, valves must be closed in order to avoid losses and room contamination. All valves must be checked before leaving the laboratory at the end of the day. Each laboratory has also cylinders containing specific gases. In the laboratory where this internship was performed, there is a carbon monoxide cylinder which is used for the determination of catalyst dispersion by chemisorption. This cylinder must always be closed when chemisorption is not being performed, since CO is a toxic gas. The laboratory has also an important electric network that feeds five furnaces, a stove, two chromatograms, a FID detector and four computers. All of this equipment, except for two computers, are controlled by an electric dashboard that consists of seven temperature controllers, twenty-five electric outlets and six switches. These switches must be all turned off at the end of the day because they cut all equipment alimentation. These are the measures that must be taken according to each one of the different procedures: Catalyst preparation: since this process begins by grinding alumina, a mask must be worn. Gloves and safety glasses are also recommended all along the process since it involves handling acid, platinum, rhenium and indium solutions. Catalyst sintering: catalyst only should be taken out from the muffle when room temperature is achieved to avoid skin burning. Catalyst rejuvenation: this process uses a methanol/trichloroethylene mixture. Methanol is toxic and trichloroethylene may cause cancer. Gloves and safety glasses must be wear. Vapors should not be inhaled. Chemisorption of CO: this technique implies the use of carbon monoxide. Laboratory windows and door must remain open all along the process to avoid contamination if CO escapes from tabulation. The other techniques do not require more precaution than what was already mentioned. Annex 4 gives safety information on the most relevant chemicals used during the internship.

16


5 personal and professional contribution// At ENSCL, internships must be performed at the end of the third, fourth and fifth academic years. The internship described in this report was performed at the end of the third year of college. Along the academic year, the student has demonstrated interest in two different branches related to chemical engineering: petrochemistry and metallurgy. In order to be able to choose which path to take in the future, the student has decided to apply for this internship at INCAPE, which is a petrochemistry and catalysis research institute. Even if this internship was more related to research, naphtha reforming catalysts represent a very important part of the petroleum refining process and are thereby also related to production and to the commercial sector. These are the reasons why the intern chose this specific research domain among those available at INCAPE. Considering this point of view, this internship was very profitable to the intern. The student worked on preparation, sintering, rejuvenation and test reactions with naphtha reforming catalysts, but before beginning the practical step, a considerable number of publications and books was read. This allowed the intern to learn not only about naphtha reforming catalysts but also about the whole reforming process, as well as internal combustion engines and petroleum. It certainly gave the student more references so that a decision about later specialization could be correctly taken. An important characteristic of this specific internship is that the intern worked constantly and very closely to a very competent researcher and teacher of the reforming catalysts domain, which is Dr. Carlos Pieck. Since reforming catalysis involves a lot of different parameters which are not easily understandable at a first approach, Dr. Pieck’s patience and explanations were very useful to the intern. Since the intern did not work alone in the laboratory and on a project that was already being carried out and that will be continued, some organization was required. Doctoral students and researchers also needed equipment to do their experiments, which means that a schedule was frequently elaborated so that everyone could do its experiments on time. All experiments carried out by the intern as well as their results were noted on a handbook that belongs to the laboratory. The intern also elaborated a personal handbook in which it was written every day. Living in Argentina for nearly 7 weeks also helped the intern improve his Spanish. The student had already had some opportunities to practice this language because of previous contacts with Argentinians, Spaniards and Mexicans. The combination of these previous notions of the language with the fact of being immerged in a Spanish-speaking country allowed the student to be able to express himself and understand native people without any problem at the end of the period. The fact of the student staying in an Argentinian friend’s house and living together with this friend’s family all along the internship surely helped a lot, not only learning Spanish but also knowing more about the Argentinian culture.

17


6 conclusion// Naphtha reforming catalysis is a component of the petroleum refining process that has reached its maturity, but it does not mean that it cannot be improved. All processes involving petroleum involve also big amounts of money, so an apparent slight difference in the conversion percentage, for example, could represent huge money savings. Therefore, researchers work on improving current Pt-Re/Al2O3 naphtha reforming catalyst by modifying it. This internship consisted in helping a research team of INCAPE carrying out experiments with sintered and rejuvenated Pt-Re-In/Al2O3 catalysts. Previous work of this team on fresh catalyst shown positive results (cf. page 8), while results obtained with sintered and rejuvenated catalyst by the intern cannot be analyzed yet. Results with sintered and rejuvenated Pt-Re-In/Al2O3 diverge from usual trimetallic reforming catalysts, such as Pt-ReSn/Al2O3 or Pt-Re-Ge/Al2O3, since dispersion and cyclohexane conversion do not drop significantly after sintering and cyclopentane conversion does not increase after rejuvenation. Work will be continued by the laboratory team. Even if this internship did not show much scientific results especially because of the short period of work, it was very profitable to the student. Important scientific knowledge was acquired and the student had a great linguistic and cultural experience. In addition to that, this internship will surely help the student in the future when deciding which path to take in chemical engineering.

18


7 references// [1] [2]

[3]

[4] [5]

[6] [7]

[8] [9] [10]

[11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22]

[23]

INCAPE 2012, Historia, Santa Fe, viewed 4 August 2012, <http://www.fiq.unl.edu.ar/incape/?page_id=5>. Parera, JM & Fígoli, NS, ‘Chemistry and processing of petroleum’, in M. Dekker (eds), Antos, GJ, Aitani, AM & Parera, JM 1995, Catalytic naphtha reforming: science and technology, New York, pp. 9-11,15. Prestvik, R, Moljord, K, Grande, K & Holmen, A, ‘Compositional analysis of naphtha and reformate’, in M. Dekker (eds), Antos, GJ & Aitani, AM 2004, Catalytic naphtha reforming: second edition, revised and expanded, 2nd edition, New York, pp. 2,14. Beltramini, JM 1994, Reforming catalysts, M. Dekker, New York. Beltramini, JN, ‘Regeneration of reforming catalysts’, in M. Dekker (eds), Antos, GJ, Aitani, AM & Parera, JM 1995, Catalytic naphtha reforming: science and technology, New York, p. 388. Lieske, H, Lltz, G, Spindler, H & Volter, J 1983, J. Catal 81, p. 8. Aitani, AM, ‘Catalytic reforming processes’, in M. Dekker (eds), Antos, GJ, Aitani, AM & Parera, JM 1995, Catalytic naphtha reforming: science and technology, New York, pp. 413-28. Haensel, V 1949, US Patents 2,479,109 and 2,479,110. Kluksdahl, HE, 1968, US Patents 3,415,737. Mazzieri, VA, Grau, JM, Yori, JC, Vera, CR & Pieck, CL, ‘Influence of additives on the Pt metal activity of naphtha reforming catalysts’, in Elsevier (eds) 2009, Applied catalysis A: General, pp. 161-68. Coq, B & Figueras, F 1984, J. Catal. 85, p. 197. Ribeiro, FH, Bonivardi, AL, Kim, C & Somorjai, GA 1994, J. Catal. 150, p. 186. Biloen, P, Duatzenberg, FM & Sachtler, WMH 1977, J. Catal. 50, p. 77. Boudart, M, Aldag, A, Benson, JE, Dougharty, VA & Harkings, CG J. Catal. 6, p. 92. Boudart, M 1976, in Proceedings of the 6th International Congress of Catalysis, The Chemical Society, London, p. 1. Baird, WC, Boyle, JP & Swan, GA 1992, U.S. Pat. 5,106,809. Bogdan, PL & Imai, T 2000, U.S. Pat. 6,048,449. Benitez, VM & Pieck, CL, Actividad y desactivación de catalizadores Pt-Re-In/Al2O3 de reformado de naftas, 15th Brazilian Catalysis Congress, 5th Mercosul Catalysis Congress. Pieck, CL, Jablonski, EL & Parera, JM, ‘Sintering-Redispersion of Pt-Re/Al2O3 during Regeneration’, in Elsevier (eds) 1990, Applied catalysis 62, Amsterdam, pp. 47-60. Matyi, RJ, Schwartz, LH & UVT, JB 1987, Catal. Rev.-Sci. Eng. 29, p. 41. Whyte, TE 1973, J. Catal. Rev.-Sci. Eng. 8, pp. 117. Mazzieri, VA 2006, PhD dissertation, Preparación y caracterización de catalizadores trimetálicos de reformado de naftas del tipo Pt-Re-Sn/Al2O3 y Pt-Re-Ge/Al2O3, Universidad Nacional del Litoral, Santa Fe, chap. 3, pp. 57-64. Boudart, M, Aldag, A, Benson, JE, Dougharty, NA & Harkins, CG 1996, J. Catal. 6, p. 92. 19


[24] [25]

Liu, K, Fung, SC, Ho, TC & Rumschitzki, DR 1997, J. Catal. 169, p. 455. Clem, KR 1977, PhD dissertation, Louisiana State University, Baton Rouge.

20


annexes//


annex #1/ Research Octane Numbers of Pure Hydrocarbonsa Hydrocarbon RON Hydrocarbon Paraffins 1,3-Dimethylcyclopentane (trans) n-Butane 113 1,1,3-Trimethylcyclopentane Isobutane 122 Cyclohexane n-Pentane 62 Methylcyclohexane 2-Methylbutane 99 Ethylcyclohexane 2,2-Dimethylpropane 100 1,1-Dimethylcyclohexane n-Hexane 19 1,1,3-Trimethylcyclohexane 2-Methylpentane 83 1,3,5-Trimethylcyclohexane 3-Methylpentane 86 Isopropylcyclohexane 2,2-Dimethylbutane 89 Aromatics 2,3-Dimethylbutane 96 Benzene n-Heptane 0 Toluene 2-Mehtylhexane 41 o-Xylene 3-Methylhexane 56 m-Xylene 3-Ethylpentane 64 p-Xylene 2,2-Dimethylpentane 89 Ethylbenzene 2,3-Dimethylpentane 87 n-Propylbenzene 2,2,3-Trimethylbutane 113 Isopropylbenzene n-Octane -19 1-Methyl-2-ethylbenzene n-Nonane -17 1-Methyl-3-ethylbenzene Olefins 1-Methyl-4-ethylbenzene 1-Pentene 91 1,2,3-Trimehtylbenzene 1-Octene 29 1,2,4-Trimethylbenzene 3-Octene 73 1,3,5-Trimethylbenzene 4-Methyl-1-pentene 96 Oxygenates Methylcyclopentane 107 Methanol Ethylcyclopentane 75 Ethanol 1,1-Dimethylcyclopentane 96 2-Propanol 1,3-Dimethylcyclopentane (cis) 98 Methyl tert-butyl ether (MTBE) a Calculated value of pure hydrocarbon from research method rating of clear mixture hydrocarbon and 80% primary reference fuel (60% isooctane + 40% n-heptane).

RON 91 94 110 104 43 95 85 60 62 99 124 120 145 146 124 127 132 125 162 155 118 148 171 106 99 90 117 of 20%

Source: Parera, JM & Fígoli, NS 1995, ‘Chemistry and processing of petroleum’, in M. Dekker (eds), Catalytic naphtha reforming: science and technology, New York, pp. 10,11.


Wt%

0.018 0.078

2.287

1.140

0.716

3.216

1.742

1.650

3.328

0.017

7.885

17.38

0.866

0.105

1.056

0.409

0.595

0.990

0.137

1.051

0.162

6.765

0.308

0.452

0.180

Compound

2,4-Dm-Pentane 3,3-Dm-Pentane

2-Me-Hexane

2,3-Dm-Pentane

1,1-Dm-CyC5

3-Me-Hexane

c-1,3-Dm-CyC5

t-1,3-Dm-CyC5

t-1,2-Dm-CyC5

C7 Olefin 7

n-Heptane

Me-CyC6

1,1,3-Tm-CyC5

2,2-Dm-Hexane

Et-CyC5

2,2,3-Tm-Pentane

2,4-Dm-Hexane

ct-124-Tm-CyC5

3,3-Dm-Hexane

tc-123-Tm-Pentane

2,3,4-Tm-Pentane

Toluene

1,1,2-Tm-CyC5

2,3-Dm-Hexane

2-Me-3-Et-Pentane

0.050 0.031

C9 naphthene 7 C9 naphthene 8

0.206

C9 naphthene 35

0.074 0.020

C10 naphthene 3

0.096

0.090

0.519

0.053

C10 naphthene 2

n-But-CyC5

C10 paraffin 3

n-Pr-CyC6

C9 naphthene 36

0.015

0.109

C10 paraffin 1 C10 paraffin 2

0.067

2,2-Dm-Octane

0.009

0.342

C9 olefin 13 iPr-CyC6

0.205

iPr-Benzene

0.046

C9 naphthene 33

0.070

C9 naphthene 31 0.062

0.036

C9 naphthene 29

C9 naphthene 32

0.052

C9 naphthene 26

2.226

0.079

C9 naphthene 24

n-Nonane

0.039

C9 naphthene 23

0.269

C9 naphthene 20 0.013

0.784 0.152

C9 naphthene 16 C9 naphthene 18 C9 naphthene 22

Wt%

Compound

continued

0.472

tt-1,2,4-Tm-CyC6

0.226

C9 naphthene 5

0.078

C9 naphthene 4 1.265

0.179

C9 naphthene 3 Ethylbenzene

0.205

0.394

0.136

0.918

0.719

0.038

3.052

0.035

0.276

0.106

0.279

0.089

0.154

3,5-Dm-Heptane

2,5-Dm-Heptane

1,1,4-Tm-CyC6

1,1,3-Tm-CyC6

2,6-Dm-Heptane

2-Me-4-Et-Hexane

Et-CyC6

4,4-Dm-Heptane

2,4-Dm-Heptane

2,2,3-Tm-Hexane

c-1,2-Dm-CyC6

2,2-Dm-Heptane

c-1,2-Et-Me-CyC5

0.066

0.074

C8 naphthene 6 c-2-Octane

0.065

0.914 5.263

Wt%

iPr-CyC5

c-1,4-Dm-CyC6 n-Octane

Compound

0.013

C10 naphthene 18

C10 naphthene 25

C10 naphthene 24

Indane

C10 naphthene 22

1,4-Me-iPr-Benz

1,3-Me-iPr-Benz

0.030

0.016

0.070

0.119

0.132

0.087

0.079

0.013

C10 naphthene 20 1,2,3-Tm-Benz

0.258

0.055 n-Decane

s-But-Benzene

0.037

0.013

C10 naphthene 17 i-But-Benzene

0.012

C10 naphthene 16

0.010

0.081

C10 naphthene 15 i-But-CyC6

0.067

0.281

0.021

0.073

0.040

0.030

0.014

0.225 0.094

Wt%

C10 naphthene 14

1,2,4-Tm-Benz

C10 paraffin 9

3-Me-Nonane

C10 paraffin 8

C10 naphthene 11

C10 naphthene 10

1-Me-2-Et-Benz 3-Et-Octane

Compound

Hydrocarbon Compositiona in a Straight-Run Naphtha from North Sea Crude, Identified by Gas Chromatography

annex #2/


0.888

0.123

0.064

0.065

2.904

1.699

1.664

0.454

0.374

0.413

0.733

0.107

1.649

0.023

4-Me-Heptane

3,4-Dm-Hexane

C8 naphthene 1

C8 naphthene 2

c-1,3-Dm-CyC6

3-Me-Heptane

3-Et-Hexane

1,1-Dm-CyC6

t-13-Et-Me-CyC5

c13-Et-Me-CyC5

t-12-Et-Me-CyC5

1-Me-1-Et-CyC5

t-1,2-Dm-CyC6

cc-123-Tm-CyC5

1.260 0.061 0.023

C9 naphthene 12 C9 naphthene 14

0.050

C9 naphthene 11 o-Xylene

0.571

3-Me-Octane

0.157

0.124

C9 naphthene 11 3-Et-Heptane

0.570

0.433

0.105

0.090

0.048

0.860

0.927

3.039

Wt%

2-Me-Octane

4-Me-Octane

4-Et-Heptane

3,3-Dm-Heptane

C9 naphthene 9

2,3-Dm-Heptane

p-Xylene

m-Xylene

Compound

4-Me-Nonane

0.025

0.030

0.042

C10 paraffin 6 C10 paraffin 7

0.076

C10 paraffin 5

0.166

0.063

C10 naphthene 9 1,3,5-Tm-Benz

0.150

1-Me-4-Et-Benz

0.383

0.039

C10 naphthene 7 1-Me-3-Et-Benz

0.145

0.065

2,6-Dm-Octane

C10 naphthene 5

0.278

0.059

C10 paraffin 4 n-Pr-Benzene

0.250

0.041

C10 naphtene 4 3,3-Dm-Octane

Wt%

Compound

n-Undecane

12-Dm-4Et-Benz

14-Dm-2Et-Benz

1,2-Me-nPr-Benz

C10 naphthene 31

13-Dm-5Et-Benz

n-But-Benzene

1,4-Me-nPr-Benz

1,3-Me-nPr-Benz

M. Dekker (eds), Catalytic naphtha reforming: second edition, revised and expanded, 2nd edition, New York, pp. 7,8.

Source: Prestvik, R, Moljord, K, Grande, K & Holmen, A 2004, â&#x20AC;&#x2DC;Compositional analysis of naphtha and reformateâ&#x20AC;&#x2122;, in

0.018

0.013

0.015

0.015

0.014

0.009

0.012

0.009

0.026

0.012

0.011

C10 naphthene 30 1,3-De-Benzene

0.036

0.040

Wt%

n-But-CyC6

C11 paraffin 2

Compound

Structures not fully identified are numbered according to type of compound and carbon number.

2.741

2-Me-Heptane

a

Wt%

Compound


annex #3/

Example of chemisorption of CO chromatogram. Experiment #4929 using fresh PtReIn(0.3) catalyst. Each peak represents one injection of CO using the sampling valve. Area delimited in blue corresponds to injections where CO was adsorbed on catalyst. Area delimited in red corresponds to injections where CO was no longer adsorbed and saturation was achieved. Catalyst dispersion was calculated considering the difference between the theoretical integration area if all peaks were saturated and the real integration area given by the software.


annex #4/ Compound Aluminum oxide, alumina Hydrochloric acid

Molecular formula Al2O3 HCl

Hexachloroplatinic acid

H2PtCl6

Ammonium perrhenate

NH4ReO4

Indium(III) nitrate

In(NO3)3

Hydrogen

H2

R & S phrases R-Phrases None listed

S-Phrases

S 24/25: avoid contact with skin and eyes R 34: causes burns (S 1/2): keep locked up and out of R 37: irritating to the reach of children respiratory system S 26: in case of contact with eyes, rinse immediately with plenty of water and seek medical advice S 45: in case of accident or if you feel unwell seek medical advice immediately (show the label where possible) R 25: toxic if swallowed S 26: in case of contact with eyes, R 34: causes burns rinse immediately with plenty of R 42/43: may cause water and seek medical advice sensitization by inhalation S 27: take off immediately all and skin contact contaminated clothing S 36/37/39: wear suitable protective clothing, gloves and eye/face protection S 45: in case of accident or if you feel unwell seek medical advice immediately (show the label where possible) R 8: contact with S 17: keep away from combustible combustible material may material cause fire S 26: in case of contact with eyes, R 36/37/38: irritating to rinse immediately with plenty of eyes, respiratory system and water and seek medical advice skin S 36: wear suitable protective clothing R 8: contact with S 17: keep away from combustible combustible material may material cause fire S 26: in case of contact with eyes, R 20/21/22: harmful by rinse immediately with plenty of inhalation, in contact with water and seek medical advice skin and if swallowed S 27: take off immediately all contaminated clothing S 36/37/39: wear suitable protective clothing, gloves and eye/face protection R 12: extremely flammable S 2: keep out of the reach of R 18: in use, may form children flammable/explosive vapour- S 15: keep away from heat air mixture S 16: keep away from sources of R 44: risk of explosion if ignition - No smoking heated under confinement S 21: when using do not smoke continued


Compound

Molecular formula

R-Phrases

Carbon monoxide

CO

R 12: extremely flammable R 26: very toxic by inhalation R 48/23: toxic: danger of serious damage to health by prolonged exposure through inhalation R 61: may cause harm to the unborn child R 11: highly flammable R 23/24/25: toxic by inhalation, in contact with skin and if swallowed R 39/23/24/25: toxic: danger of very serious irreversible effects through inhalation, in contact with skin and if swallowed

Methanol

CH4O

Trichloroethylene

C2HCl3

R 25: toxic if swallowed R 45: may cause cancer R 36/38: irritating to eyes and skin R 52/53: harmful to aquatic organisms, may cause longterm adverse effects in the aquatic environment

Cyclohexane

C6H12

R 11: highly flammable R 38: irritating to skin R 65: harmful: may cause lung damage if swallowed R 67: vapours may cause drowsiness and dizziness R 50/53: very toxic to continued

S-Phrases S 37: wear suitable gloves S 51: use only in well-ventilated areas S 45: in case of accident or if you feel unwell seek medical advice immediately (show the label where possible) S 53: avoid exposure - obtain special instructions before use

(S 1/2): keep locked up and out of the reach of children S 7: keep container tightly closed S 16: keep away from sources of ignition - No smoking S 36/37: wear suitable protective clothing and gloves S 45: in case of accident or if you feel unwell seek medical advice immediately (show the label where possible) S 2: keep out of the reach of children S 20: when using do not eat or drink S 23: do not breathe gas/fumes/vapour/spray (appropriate wording to be specified by the manufacturer) S 45: in case of accident or if you feel unwell seek medical advice immediately (show the label where possible) S 53: avoid exposure - obtain special instructions before use S 61: avoid release to the environment. Refer to special instructions/safety data sheet S 24/25: avoid contact with skin and eyes S 36/37: wear suitable protective clothing and gloves (S 2): keep out of the reach of children S 9: keep container in a wellventilated place S 16: keep away from sources of ignition - No smoking S 25: avoid contact with eyes


Compound

Molecular formula

R-Phrases

S-Phrases

aquatic organisms, may cause long-term adverse effects in the aquatic environment

S 33: take precautionary measures against static discharges S 60: this material and its container must be disposed of as hazardous waste S 61: avoid release to the environment. Refer to special instructions/safety data sheet S 62: if swallowed, do not induce vomiting: seek medical advice immediately and show this container or label where possible S 9: keep container in a wellventilated place S 16: keep away from sources of ignition - No smoking S 29: do not empty into drains S 33: take precautionary measures against static discharges S 61: avoid release to the environment. Refer to special instructions/safety data sheet (S 2): keep out of the reach of children S 16: keep away from sources of ignition - No smoking S 29: do not empty into drains S 33: take precautionary measures against static discharges

Cyclopentane

C5H10

R 11: highly flammable R 52/53: harmful to aquatic organisms, may cause longterm adverse effects in the aquatic environment

n-Heptane

C7H16

R 11: highly flammable R 38: irritating to skin R 50/53: very toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment R 65: harmful: may cause lung damage if swallowed R 67: vapours may cause drowsiness and dizziness

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