The influence of modification methods on the catalytic cracking of LPG over lanthanum and phosphorus modified HZSM-5 catalysts

CATEGORY: LPG: CATALYTIC CRACKING
The influence of modification methods on the catalytic cracking of LPG over lanthanum and phosphorus modified HZSM-5 catalysts

Type	Journal Article
Author	N. Rahimi
Author	D. Moradi
URL	http://www.sciencedirect.com/science/article/pii/S1387181116302657
Volume	234
Pages	215-223
Publication	Microporous and Mesoporous Materials
Date	November 1, 2016
Abstract	Researchers examined the effect of various modification methods on the activity of ZSM-5 modified catalysts in catalytic cracking (CC) of LPG. They loaded lanthanum (La) in HZSM-5 catalyst using ion exchange, and wet impregnation, and introduced phosphorus (P) by wet impregnation and dry impregnation methods. The catalytic performance of the samples revealed that wet impregnation offers better efficiency than dry impregnation and ion-exchange methods. They observed that HZSM-5 catalyst modified by successive wet impregnation of La and P could led to the higher conversion and yield of light olefins (ethylene + propylene) compared to the other samples.

Enthalpy Determination for Catalytic Cracking of Normal Alkanes to Light Olefins over HZSM-5 Utilizing Differential Scanning Calorimetry with a Packed-Bed Reactor

CATEGORY: CATALYTIC CRACKING
Enthalpy Determination for Catalytic Cracking of Normal Alkanes to Light Olefins over HZSM-5 Utilizing Differential Scanning Calorimetry with a Packed-Bed Reactor
NAM24-24th North American Catalysis Society Meeting, Pittsburgh, PA, June 14-19, 2015
Taslima Zaman, Ji Woong Chang and Robert Rioux, Pennsylvania State University, USA.
Introduction
Light olefins such as ethylene and propylene are used to make “clean” fuels, which burn and do not inhibit the functioning of catalytic converters in engine exhaust1. Light olefins are obtained as a by-product predominantly from steam cracking of naphtha, which requires high temperature operating conditions (800 - 900C)2 and therefore is very energy consuming. The implementation of catalytic cracking requires less energy (550 - 650C)2 and produce light olefins with higher selectivity. There a number of applications where product selectivity coupled with the overall net energy requirement are critical.
The highly active, highly stable USY zeolite is extensively used in FCC processes. H owever, the large pores and supercages are more suitable for cracking heavier hydrocarbon molecules present in crude oil. The large voids promote hydride transfer and drive undesirable side reactions producing coke precursors and causing low olefin selectivity and short catalyst lifetime. Medium pore zeolites hinder the transition states formed by the hydride transfer and forces cracking to proceed via the monomolecular mechanism and favors light olefin production. Amongst the many medium pore zeolites studied including ZSM-57, ferririte, ZSM-22 and small pore zeolites including chabazite, ZK-5 and ZSM-58, HZSM-5 stood out in terms of activity, stability and selectivity for light olefin production3.
In this study, the enthalpy of n-butane cracking over HZSM-5 will be measured using differential scanning calorimetry (DSC). We have utilized n-butane as a probe reactant because it is small and symmetric enough to keep the product distribution as simple as possible while providing various reaction pathways sufficient to represent alkane cracking. Due to multiple reactions taking place simultaneously (primary and secondary) in n-butane cracking, it is difficult to accurately measure enthalpy contributions from any one reaction. Hence, the impact of side reactions will also be investigated. We have also examined propane cracking and propylene oligomerization due to their simpler product distribution.
Materials and Methods
Experiments were performed using a Setaram SENSYS evo DSC calorimeter with a computerized data acquisition system. The unit was modified for continuous steady-state flow operation with a working range from ambient to 830C. Calibrations for temperature and enthalpy were performed using the melting transitions of 99.999% purity standards of indium (156.6C), tin (231.9C), lead (327.5C), zinc (419.5C) and aluminum (660.3C). To obtain a baseline for DSC analysis, helium (purity > 99.999%) was used as the purge gas. Separate sample and reference lines were used and similar flow rates were maintained using electronic
 flow controllers. Quartz reactors (27 cm length and 0.6 cm I.D.) were carefully packed within the 20 mm DSC furnace zone with 50 mg catalyst (sample side: HZSM-5, CBV2314 from Zeolyst with Si/Al = 23, reference side: silica) loaded between beds of quartz wool. The reactor was operated at atmospheric pressure and 500C. Product gases were fed through stainless steel lines to an automated gas chromatography-mass spectrometry (Shimadzu GCMS QP-2010 Ultra).
Results and Discussion
DSC provides a convenient method for measuring quantitatively the heat flow to a sample as the temperature difference develops between the sample and the reference and compensating with a corresponding power input. Therefore, the reaction can be considered isothermal even at high levels of conversion. The heat of n-butane cracking is determined by integrating the heat flow curves against time (Figure 2). An overall energy balance on the reactor was used to calculate the heat of reaction for n-butane central cracking. Comparison of the calculated and the expected heat of reactions along with the product distribution obtained from the GC-MS indicate the secondary reactions have significant influence on the observed heat flow even at low conversion of reactions leading to secondary products.
Significance: FCC units produce only around 5 wt. % of light olefins. Kinetic and thermodynamic evaluations could help engineer a catalyst with better selectivity and activity to improve light olefin yields to meet the growing demands.
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Continuous Age Distribution Method for Catalytic Cracking

CATEGORY: CATALYTIC CRACKING
Continuous Age Distribution Method for Catalytic Cracking
NAM24-24th North American Catalysis Society Meeting, Pittsburgh, PA, June 14-19, 2015
David Stockwell, BASF Corporation, USA.
Introduction
Continuous catalyst replacement during fluidized catalytic cracking (FCC) leads to an exponential distribution of catalyst ages in the working ‘equilibrium’ catalyst mixture (E-cat). Fluid bed regeneration of coke-laden catalyst with air results in ~25 kPa of steam at ~975 K, which deactivates the zeolite Y-based catalyst by simultaneously hydrolyzing tetrahedral framework aluminum (dealumination, AlT) and tetrahedral framework silicon (SiT). Dealumination occurs rapidly [1], reaching a pseudo-equilibrium of ~80% AlT removal within a day or two, but SiT loss is much slower, with nominally 50% of SiT collapsing over 80 days. FCC catalysts also commonly contain a separate alumina or stabilized alumina matrix [2], and most of these are hydrothermally very stable. The selectivity characteristics of zeolite and matrix differ however. Clearly then, the activity and more importantly the selectivity of cracking catalyst can be expected to vary with age, the overall performance of the E-cat being due to both the discrete properties of a given age as well as its percentage within the mixture.
Despite the significance of the age distribution, this effect is typically neglected when simulating refinery catalyst deactivation in the laboratory. Empirical age distribution methods have been proposed before [3] but these are cumbersome and provide no guidance on conditions needed to match a specific refinery.
Materials and Methods
A Continuous Age Distribution Method (CADM) of steam-deactivation has been developed which reproduces the full distribution of zeolite micropore surface area found in refinery E-cat (Fig. 1), doing so in a single steaming. A screw feeder continuously adds fresh FCC catalyst to an initially empty steaming reactor, the temperature of which declines with time according to a logarithmic profile which depends on the kinetics of SiT decay in the lab and the refinery, and on the replacement rate of catalyst in the refinery. A literature correlation with unit cell dimension is used to separate the contributions of AlT and SiT to the overall micropore area. The method is based on fundamental kinetic and reactor models, and so has the potential to both reproduce and predict, a priori, refinery catalyst performance.
Results and Discussion
Arrhenius plots of laboratory steaming data were initially found nonlinear and in poor agreement with rates derived from refinery E-cat. A new calibration algorithm and Ea hypothesis testing then showed that Ea=117 kcal/mol made the properties of the catalyst in the steamer continually match the targeted E-cat for up to 7 days. Intermittent operation of the feeder allowed us to prepare discrete 10 wt% segments within the age distribution, and the results of Fig. 1 show that CADM-steamed catalyst segment properties were very similar to
 expectations based on density separations and 1st order SiT decay. We next varied the refinery catalyst replacement rate (1/R), and while we obtained a directionally correct response for activity and micropore area, the results deviated systematically from 1st order decay.
After harshly pre-steaming FCC catalyst, Pine [4] found that Arrhenius plots were linear and that vanadium and sodium affected ko but not Ea. In ongoing work we find that fresh commercial zeolites contain 10-20% of metastable SiT which can be eliminated by a mild presteaming. Subsequent Arrhenius plots are straight and agree with refinery decay rates. This allows us to eliminate the dependence of the CADM ramp on ko since ko is the same in the lab as the refinery. The initial nonlinearity was thus due to the metastable SiT. After presteaming, all Y zeolites investigated so far by us give Ea ≈ 80 kcal/mol, even with vanadium, in agreement with Pine [4]. Since Ea = 80 kcal/mol for all Y zeolites and ko has been eliminated, CADM requires no further calibration. If a base catalyst fails to match the E-cat target, adjustments can be made to the CADM temperature ramp via the regenerator temperature TR or steam pressure PS,R to correct the offset. Once the reference catalyst is on target, other catalysts will also necessarily give their correct micropore areas for that FCC unit.
Separately, we find that by varying CADM addition time L the selectivity of lab-deactivated samples can be made to match low metals E-cat in nearly every detail.
The effects of V and Na are embedded in ko so if laboratory V and Na match the refinery, the CADM calibration will not change. But (1/R) may need to increase to compensate for zeolite destruction, just as in the refinery. CADM is expected to reduce contaminant H2 and coke.
Significance: CADM provides a fundamentally sound method to comprehensively reproduce E-cat in the laboratory. The ability to accurately reproduce and predict catalyst properties and performance should enable for the first time truly quantitative analysis of refinery operations.
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Life and death of a single catalytic cracking particle

CATEGORY: CATALYTIC CRACKING 
Life and death of a single catalytic cracking particle

Type	Journal Article
Author	Florian Meirer
Author	Sam Kalirai
URL	Free Full Text Source:  http://advances.sciencemag.org/content/1/3/e1400199
Volume	1
Issue	3
Pages	e1400199
Publication	Science Advances
Date	2015/04/01
Abstract	Fluid catalytic cracking (FCC) particles account for 40 to 45% of worldwide gasoline production. The hierarchical complex particle pore structure allows access of long-chain feedstock molecules into active catalyst domains where they are cracked into smaller, more valuable hydrocarbon products (for example, gasoline). In this process, metal deposition and intrusion is a major cause for irreversible catalyst deactivation and shifts in product distribution. We used x-ray nanotomography of industrial FCC particles at differing degrees of deactivation to quantify changes in single-particle macroporosity and pore connectivity, correlated to iron and nickel deposition. Our study reveals that these metals are incorporated almost exclusively in near-surface regions, severely limiting macropore accessibility as metal concentrations increase. Because macropore channels are “highways” of the pore network, blocking them prevents feedstock molecules from reaching the catalytically active domains. Consequently, metal deposition reduces conversion with time on stream because the internal pore volume, although itself unobstructed, becomes largely inaccessible. Macropore blocking through metal deposition and intrusion of particles is a major deactivation mechanism in FCC catalysts essential to gasoline production. Macropore blocking through metal deposition and intrusion of particles is a major deactivation mechanism in FCC catalysts essential to gasoline production.

Device for controlling the operating conditions in a catalytic cracking unit with two risers (IFP Energies Nouvelles)

CATEGORY: CATALYTIC CRACKING
Device for controlling the operating conditions in a catalytic cracking unit with two risers (IFP Energies Nouvelles)

Type	Patent
Inventor	Frederic Feugnet
Inventor	Thierry Gauthier
URL	Free Full Text Source:  http://www.google.com/patents/US8957267
Assignee	IFP Energies Nouvelles
Patent Number	US8957267 B2
Issue Date	Feb 17, 2015
Abstract	The invention concerns a process for the production of gasoline and for the co-production of propylene using a catalytic cracking unit comprising a catalyst regeneration zone and a reaction zone with two risers functioning in parallel under different severity conditions, the catalyst circulating between the regeneration zone and the reaction zone in two parallel circuits, a circuit termed the principal circuit comprising a first external catalyst cooling system, and a circuit termed the secondary circuit comprising a second external catalyst cooling system.

Catalytic Cracking Reaction of Heavy Oil in the Presence of Cerium Oxide Nanoparticles in Supercritical Water

Energy Fuels, 2013, 27 (8), pp 4624–4631, DOI: 10.1021/ef400855k, Publication Date (Web): July 19, 2013
Catalytic Cracking Reaction of Heavy Oil in the Presence of Cerium Oxide Nanoparticles in Supercritical Water
Mehdi Dejhosseini †‡, Tsutomu Aida , Masaru Watanabe §, Seiichi Takami ‡, Daisuke Hojo #, Nobuaki Aoki #, Toshihiko Arita ‡, Atsushi Kishita , and Tadafumi Adschiri *‡#
ajiri@tagen.tohoku.ac.jp
† Graduate School of Engineering, Tohoku University, 6-6 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579, Japan
‡ Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
§ Research Center of Supercritical Fluid Technology, Tohoku University, 6-6-11 Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan
New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579, Japan
Department of Environmental Science and Technology, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8579, Japan
# World Premier International Research Center-Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
Abstract
Researchers conducted catalytic cracking of Canadian oil sand bitumen in supercritical water to understand the effect of CeO2 nanoparticles. They conducted cracking at 723 K to promote a redox reaction between the water, bitumen, and catalyst for the production of hydrogen and oxygen. CeO2 with two distinct morphologies was used as the catalyst, since the redox reaction of CeO2 with water and organics is expected and its activity can be controlled by its structure. The two roles of water were considered as well.
Water is attractive as a high potential medium with low dielectric constant and density at near the critical point, enabling formation of highly crystalline smaller metal oxides particles. However, the chemical effects of water were studied with heavy oil catalytic cracking. Transmission electron microscopy images indicated that CeO2 nanoparticles with cubic and octahedral shape were synthesized using a plug-flow reactor under hydrothermal conditions.
The particles sizes were 8 and 50 nm for cubic and octahedral CeO2, respectively. Researchers noted that at 773 K the oxygen storage capacity (OSC) of the cerium oxide nanoparticles with cubic {100} facets was nearly 3.4 times higher than that of the cerium oxide nanoparticles with octahedral {111} facets. Heavy oil fractions of bitumen were cracked in a batch-type reactor at 723 K in order to produce as much light oil as possible. The effect of the catalyst loading and reaction conditions on the conversion rate and coke formation were investigated.
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Process for converting a heavy feed using a catalytic cracking unit and a step for selective hydrogenation of the gasoline obtained from catalytic cracking (IFP Energies Nouvelles)

PATENT
Process for converting a heavy feed using a catalytic cracking unit and a step for selective hydrogenation of the gasoline obtained from catalytic cracking (IFP Energies Nouvelles)
Publication number
US20130211161 A1
Publication type
Application
Application number
US 13/767,072
Publication date
Aug 15, 2013
Inventors
Frédéric FEUGNET, Francois Hugues, Natacha Touchais, Hugues Dulot, Annick Pucci,
Original Assignee
IFP Energies Nouvelles
Abstract
The present invention describes a process for converting a heavy feed which is flexible for the production of propylene, gasoline and middle distillate.
The process uses a catalytic cracking unit and a unit for the oligomerization of C4 to C9 olefins. The process of the invention includes selective hydrogenation of the unrefined gasoline cut obtained from the catalytic cracking unit and separation between a light gasoline cut and a heavy gasoline cut, the light gasoline being directed to the oligomerization unit.
Description
FIELD OF THE INVENTION
The invention relates to a process for converting a heavy hydrocarbon feed exhibiting great flexibility for the production of middle distillate, gasoline and propylene.
The process of the present invention uses a catalytic cracking unit (FCC).
Generally, such catalytic cracking units are optimized with a view to the production of light products: liquefied gas (or LPG), light olefins and gasoline, in order to satisfy the needs of either the market for polymers obtained from the polymerization of light olefins or gasoline consumption requirements in the automotive industry.
Currently, given the substantial increase in the use of diesel in the automotive industry, the demand for products of the middle distillate type has increased substantially.
As a consequence, another mode of operation of the catalytic cracking unit has been developed, with a view to orientating production towards middle distillates.
The flexibility in and improvement to yields as regards one or other of the three products are accomplished by adding an oligomerization unit treating C4 to C9 olefins obtained from FCC or from other additional sources such as the coking unit, visbreaking unit, the unit for converting methanol into olefins or any other process for converting alcohols into olefins, steam cracking or indeed the Fischer-Tropsch synthesis unit, or from the paraffin dehydrogenation unit, used alone or as a mixture.
A description of coking, visbreaking and steam cracking units can be found in the reference work “Raffinage et génie chimique” [Refining and chemical engineering] by P Wuithier, published by Technip.
The oligomerization unit requires a purification step in order to reduce the quantity of nitrogen-containing compounds, which are poisonous to the reaction. The dienes and sulphur-containing compounds present in the oligomerization feed, which are inhibitors or poisonous to the reaction, are generally not reduced in that purification step and have a negative impact on the cycle period of the catalyst.
The present invention essentially consists of adding a step for selective hydrogenation of the gasoline leaving the FCC (i.e. upstream of the oligomerization unit), which can be used to limit the quantity of those inhibitors and thus increase the cycle period of the oligomerization catalyst without altering the distribution of the desired products.
EXAMINATION OF THE PRIOR ART
Patent application FR 2 935 377 concerns a process for converting a hydrocarbon feed termed a heavy feed with a view to the co-production of propylene and of gasoline with a minimum yield. The process of that invention comprises at least two reaction steps, a first, catalytic cracking step and a second step for the oligomerization of C3 and C4 olefins or C4 olefins or C4 and C5 olefins from the catalytic cracking step.
The process of the cited patent can be used to carry out two types of production, corresponding to two distinct working modes:
• ◦a “maxi propylene” mode, corresponding to maximum production of propylene while keeping the gasoline yield to a minimum, or even slightly increased compared to the potential yield from the catalytic cracking unit alone; or
◦a “maxi gasoline” mode, corresponding to maximum production of gasoline without the production of propylene.
In that patent, only C3, C4 and C5 olefins are mentioned.
Application FR 10/04585 describes a process for converting a heavy feed that can be used to improve the selectivity for middle distillate. The process uses a catalytic cracking unit followed by one or more units for the oligomerization of olefins containing 2 to 9 carbon atoms in order, preferably, to produce an additional middle distillate cut. The light portion of the oligomerizate produced, which cannot be incorporated into the middle distillate cut, is recycled to the FCC for cracking into light olefins which return to the oligomerization units as a supplement to the olefins of the feed in order, preferably, to form heavy oligomerizates which can be incorporated into the middle distillate cut.
In that application, the oligomerized C2 to C9 cut is constituted by a portion of the FCC products without carrying out any other processes before oligomerization.
Patent FR 2 797 639 B1 describes a process for the production of gasoline with a low sulphur content, comprising a step for selective hydrogenation of diolefins and optionally at least one step aimed at increasing the molecular weight of the light sulphur-containing products present in the gasoline. The cited patent describes separating the gasoline into two fractions: light gasoline and heavy gasoline, and can be used to produce low sulphur gasolines.
Patent FR 2 895 416 B1 describes a catalytic system that can be used to carry out joint selective hydrogenation of polyunsaturated compounds into monounsaturated compounds contained in the gasolines, as well as to make light sulphur-containing compounds heavier by reaction with the unsaturated compounds.
In the cited patents, the intended aim is to obtain a gasoline without substantial loss of octane number and with a low sulphur content, with the gasoline entering the fuel pool.
In the context of the present invention, using a selective hydrogenation unit on the gasoline cut obtained from the catalytic cracking unit before separating the light gasoline and the heavy gasoline means that a light C5-C9 gasoline cut can be obtained with a reduced quantity of diolefins and also of sulphur, which can be sent directly to the final purification unit (reduction of nitrogen-containing compounds) preceding the oligomerization unit. By using it this way, the cycle period for the oligomerization catalysts is significantly improved without altering the distribution of the desired products.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 represents a layout of the process of the invention. The dashed lines represent the optional supplies or recycles. The notations assigned to the units are introduced in the remainder of the text.
BRIEF DESCRIPTION OF THE INVENTION
The invention consists in a process for converting a heavy hydrocarbon feed with great flexibility for the production of middle distillate, gasoline and propylene, using a catalytic cracking unit (FCC) followed by a unit for the selective hydrogenation (SHU) of the gasoline obtained from the FCC unit.
The gasoline obtained from the catalytic cracking unit has an end point that differs depending on whether a maxi gasoline or a maxi distillate mode is desired.
• ◦for the maxi gasoline mode, the ex FCC gasoline is preferentially defined as C5-220° C.;
◦for the maxi distillate mode, the ex FCC mode is preferentially defined as C5-150° C.
This distinction is important since, given the flexibility of the process, it is essential to keep in mind the definition of the FCC outlet gas which should be taken into account in each case.
The process of the invention may also function in accordance with a “maxi propylene” mode, which is compatible with any end point of the gasoline in the range 150° C. to 220° C. This “maxi propylene” mode is essentially obtained by the operating conditions of the catalytic cracking unit (known as “high severity” conditions) and by using a catalyst incorporating a certain proportion of ZSM-5 zeolite.
Free Full Text Source: http://www.google.com/patents/US20130211161

Influence of [H]-donating activity of hydrocarbons on transformations of thiophene compounds under catalytic cracking conditions

CATEGORY: CATALYTIC CRACKING
Petroleum Chemistry, January 2012, Volume 52, Issue 1, pp 55-59
Influence of [H]-donating activity of hydrocarbons on transformations of thiophene compounds under catalytic cracking conditions
O. V. Potapenko, V. P. Doronin, T. P. Sorokina
Institute of Hydrocarbon Processing Problems, Siberian Branch, Russian Academy of Sciences, Omsk, Russia
Abstract
Researchers examined transformations of 2-methylthiophene and benzothiophene together with n-undecane, declaim, or cumene under conditions of catalytic cracking. Findings indicate that enhancement of the [H]-donating activity in the order cumene < n-undecane < decalin leads to an increase in the degree of conversion of organic sulfur compounds, predominantly yielding hydrogen sulfide.
Researchers noted an increase in the amount of 2-methylthiophene and benzothiophene alkylation and condensation products in the liquid products of cracking. They propose conversion methods for these compounds under catalytic cracking conditions. They describe the dependence of the degree of conversion of thiophene compounds into hydrogen sulfide on the ability of the catalyst to mediate hydrogen transfer reactions.
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