MXPA06011642A - A shaped particle and a dehydrogenation process using it - Google Patents

Abstract

A shaped particle suitable for use as a catalyst support or, alternatively, a dehydrogenation catalyst system in the form of a shaped particle, wherein said shaped particle has a geometry including a length and a cross-sectional geometry at least one point along said length, wherein said cross sectional geometry is defined by an asymmetrical shape having an imaginary dividing line providing for an upper end, having an upper end cross sectional area, and a lower end, having a lower end cross sectional area, wherein said upper end cross sectional area is greater than said lower end cross sectional area. The cross sectional geometry may further be characterized as having a perimeter and as defining a plurality of notches with each said notch of said plurality of notches having a groove depth and a groove opening rotational distance.

Description

CONFORMED PARTICLE AND DEHYDROGENATION PROCESS USING THE SAME FIELD OF THE INVENTION The invention relates to a shaped particle. In one aspect, the invention relates to a shaped particle that can be suitably used as a catalyst support. Another aspect of the invention relates to a catalyst system of shaped particles having a specific geometry. BACKGROUND OF THE INVENTION There has been a continuing effort to design and develop shaped catalyst particles that provide certain desired properties or even improved properties over certain forms of the prior art when used in a reactor catalyst bed of a catalytic process. A number of catalyst forms have been described in the prior art. The U.S. patent No. 3,966,644 discloses a porous, shaped, hydrotreating catalyst particle characterized in that it has a cross section with a concave geometry, extending to a sufficient length along its axis to provide a solid particle. The concave geometry is preferably polylobular because the lobes arise from the circles of equal diameter and are connected to form a closed curve. The geometry of Ref. 176223 most preferred cross section of the particle is a polylobular shape with three or more lobes of circles of equal diameter. The shaped concave hydrotreating catalyst taught is presented having an advantageous catalytic activity in the hydrotreating of the petroleum residue. It is significant to note that the shapes taught by the 644 patent are either radially symmetrical or bilaterally symmetrical. The U.S. patent 4,391,740 discloses an extruded, shaped catalyst particle having a polylobular cross section that can be used in the hydroprocessing of hydrocarbon-containing raw materials containing sulfur and metals. The catalyst particles can be elongated extruded materials of a defined non-circular cross-section that can be circumscribed by a rectangle of particular dimensions. The specific shapes include an oval cross section, or an oval with an outstanding cross section, or an oval with two projecting cross sections. It is held that the forms of the '740 patent provide an improved ratio of the surface to the volume of the particle and these beds of the shaped catalyst will provide lower pressure drops than the other comparative shapes. It was pointed out that the shapes taught by the 740 patent are symmetrical.

The U.S. patent 4,495,307 discloses a cylindrical hydrotreating catalyst particle having a polylobular cross section in which the individual lobes are separated by concave interstices that are clearly rounded with a greater curvature than that of the lobes. The shape can also be defined with reference to an equilateral triangle. The shaped catalyst taught in the '307 patent is proposed to have improved properties on the trilobal form catalyst particles of the prior art as described in U.S. Pat. 3,232,887, such as the provision of better catalytic activity and improvements in pressure drop. It is noted that the shapes taught by the patent? 307 are bilaterally symmetrical. The U.S. patent No. 4,673,664 describes a hydrotreating catalyst particle, which is made of polylobular extruded materials, with helical lobes, having the shape of three or four cords wound helically around the extrusion axis along the length of the particles. The helical shape is assumed to provide an improved pressure drop across a fixed reactor bed of the catalyst particles. It is noted that the shapes taught by the? 664 patent are either radially symmetrical or bilaterally symmetrical. The U.S. patent 5, 097,091 discloses a gear wheel-shaped catalyst for use in the dehydrogenation of hydrocarbons. The cogwheel-shaped particles have at least three teeth and dimensional relationships specifically defined for such dimensions as the ratio of the diameter of the circle of the crown to the diameter of the circle of the root, the ratio of the width of the gap on the root of the tooth with respect to the width of the tooth on the crown, and the width of the hole on the root of the tooth. The tooth-shaped catalyst is supposed to provide improved activity and selectivity relative to a comparable catalyst. It is noted that the forms taught by the patent? 091 are either radially symmetrical or bilaterally symmetrical. DE 102 26 729 A1 discloses a shaped particle having notches and which may be a catalyst containing ferric oxide. The figures of DE 102 26 729 A1 show either a single-notch shape or a two-notch shape. The two-notch shape of the patent appears to have a radial symmetry. There is no presentation of a shaped particle having a plurality of notches that lack both bilateral symmetry and radial symmetry. Although the catalyst forms described above can provide several benefits when used in certain catalytic processes, there is always a need to find catalytic forms that can provide certain specific benefits that other comparative forms do not provide or a combination of beneficial properties that can provide improvements over the catalytic forms of prior art. BRIEF DESCRIPTION OF THE INVENTION Accordingly, it is an object of this invention to provide a shaped particle that can be suitably used as a support for the catalyst components. It is another object of this invention to provide a shaped catalyst particle that can be used as a component of a catalyst bed of a reactor system. Therefore, according to the invention, a shaped particle is provided. The shaped particle has a geometry that includes a length and a cross-sectional geometry in at least one point along the length with the cross-sectional geometry that is defined by an asymmetric shape having an imaginary division line that provides an upper end, having a cross-sectional area of the upper end, and a lower end, having a cross-sectional area of the lower end. The cross-sectional area of the upper end is larger than the cross-sectional area of the lower end. The shaped particle can be suitably used as a support for a catalyst component, or the shaped particle itself can be a catalyst system. According to another invention, a dehydrogenation process is provided which comprises contacting under dehydrogenation reaction conditions, a dehydrogenation feed with a dehydrogenation catalyst system based on iron oxide which is in the form of a shaped particle . The shaped particle comprises iron oxide and has a geometry that includes a length and a cross-sectional geometry in at least one point along the length, wherein the cross-sectional geometry is defined by an asymmetric shape having a line imaginary division which provides an upper end, having a cross-sectional area of the upper end, and a lower end, having a cross-sectional area of the lower end, wherein the cross-sectional area of the upper end is greater than the cross-sectional area of the lower end. BRIEF DESCRIPTION OF THE FIGURES Figure 1 is a perspective view of a three-notch shape of the shaped particle of the invention. Figure 2 is a cross-sectional view of the three-notch shaped particle of Figure 1 taken along line 2-2 of the section. Figure 3 is a cross-sectional view of a five-notch embodiment of the shaped particle of the invention. DETAILED DESCRIPTION OF THE INVENTION This invention relates to a multiple notched shaped particle that can be suitably used as a catalyst support on which a catalyst component is incorporated. A particularly desirable aspect of the invention further relates to a dehydrogenation catalyst system which is in the form of a particle formed of multiple notches. A unique feature of the multiple notch shaped particle is in its geometry that provides a charged particle with a weight. It is believed that the weight loading of the particle promotes a desired orientation and more uniform packing of the multi-notched shaped particle within a catalyst bed when it is loaded in a reactor to form the catalyst bed. This weight loading of the multi-notched shaped catalyst particles is particularly important with the multi-notched shaped catalyst particles that are for use in the dehydrogenation of hydrocarbons. When reference is made here to a particle loaded with a weight, what is meant is that the particle has a cross section and a length such that they provide a shaped particle or pellet having a non-symmetric cross-section geometry. The geometry of the cross section of the shaped particle is not symmetrical to provide a portion of the cross section that has a larger cross-sectional area than the remaining portion of the cross section. When the particle having the non-symmetric cross-section is composed of a homogeneous support material or a homogeneous catalytic material, it will be charged in the sense that the portion of the particle having the largest cross-sectional area will be heavier than the remaining portion because it contains a larger amount of mass. An alternative way of characterizing the cross section of the charged particle with a weight is to define the cross section having at least one imaginary division line passing through the central axis of the charged particle with a weight whereby two portions of the cross section of the particle loaded with a weight, with a portion of the cross section that is on one side of the imaginary division line and a remaining portion of the cross section that is on the opposite side of the division line. When the cross section is defined in this manner, it is preferred for it to be at least one imaginary division line dividing the cross section to provide a ratio of the cross sectional area of the cross sectional portion to the sectional area cross section of the remaining portion of the cross section that will be in the range from about 1.1: 1 to about 4: 1. A preferred ratio of the cross-sectional area of the cross-sectional portion with respect to the cross-sectional area of the remaining portion of the cross-section is in the range from 1.25: 1 to 3: 1, and, it is even more preferred to ratio that is in the range from 1.5: 1 to 2.5: 1. A typical goal for the ratio is approximately 2: 1. A method of loading a reactor vessel with the catalyst particles is to discharge them into the reactor vessel and allow the particles to fall freely into the reactor vessel to form a catalyst bed. Another method may include the use of a short half load within which the catalyst particles are poured with the short half which is used to direct the flow of the catalyst particles inside the reactor vessel and to limit the distance that the catalyst particles they fall freely before they land on the catalyst bed that is formed. Other methods of loading a reactor vessel may include the use of pneumatic devices or other transport devices to transfer the catalyst particles to the reactor vessel. In all of these methods, the catalyst particles that are placed in the reactor vessel fall some distance before landing and form the catalyst bed inside the reactor vessel. It is believed that the shaped particles of the invention, described herein, will provide an improved, packed catalyst bed, providing a more uniform placement of the shaped particles within the packed bed. Accordingly, when charged in a reactor vessel, the free-weighted, free-falling particles will themselves be oriented in such a manner in the formed catalyst bed that there is a certain uniformity in the placement of the catalyst particles. When reference is made here to the shaped particles that are not symmetrical, it is understood that it is that particle that lacks both bilateral symmetry and radial symmetry. The bilateral symmetry is when the shape can be divided by a plane into two essentially identical halves. The radial symmetry is when the shape is symmetric with respect to an axis in such a way that the similar parts are arranged regularly around a central axis. To more fully illustrate and describe the shaped particles of the invention, reference will now be made to the figures that present various embodiments of the invention. Figure 1 is a perspective view of a shaped particle 10 of three notches. The shaped particle of three notches is characterized in that it has a length 12 and a geometry of cross section 14 which is asymmetric in shape. At a point along the length 12 of the shaped particle 10 of three notches, a plane of cross section 2-2 is taken, which is perpendicular to the central axis (not shown) of the shaped particle 10 of three notches. With reference to Figure 2, there is shown a cross-sectional view 2-2 of the cross-sectional geometry 14 defined in part by an imaginary perimeter 16, which may have any suitable configuration or shape, but as shown in the figure 2, the imaginary perimeter 16 approaches a circle having a central axis 18. The imaginary perimeter 16 is further defined having a diameter 20 and an imaginary divider line 22 passing through the axis 18. The imaginary division line 22 is provides for, or otherwise divides, the cross-section geometry 14 at one end or upper half 24 and one end or lower half 26. The term imaginary perimeter 16, as used herein, refers to the boundary or outer edge of the cross section geometry 14, which is generally defined by the matrix or the shape by which the shaped particle 10 of three notches is formed. The imaginary perimeter 16 is imaginary in the sense that, if the cross-section geometry 14 does not include notches, the imaginary perimeter 16 could be approximated to a circular shape having a central axis 18. Accordingly, the central axis 18 is the center of the imaginary perimeter 16. The imaginary division line 22 passes through the central axis 18. Again, the imaginary division line 22 is imaginary in the sense that, if the cross section geometry 14 does not include notches, the imaginary perimeter 16 could approach a circular shape. The imaginary division line 22 divides the cross-section geometry 14 into two sections with one of the sections having a cross-sectional area greater than the cross-sectional area of the other section. Due to the length of the shaped particle, the section having the larger cross-sectional side will have a larger mass than the remaining section with the smaller cross-sectional area, thus providing a charged shaped particle. It is understood that the imaginary perimeter 16 can generally be circular and that it can be elongated or deviated somewhat from a perfect circle due to the variations resulting from the methods and manufacturing conditions.

The cross-sectional geometry 14 defines a plurality of notches including the first groove 28, the second groove 30 and the third groove 32. The first groove 28, the second groove 30 and the third groove 32 are respectively defined by a depth 34 of the first notch, the depth 36 of the second notch, and the depth 38 of the third notch. The depth of the notch is the shortest distance of a line from a point on the imaginary perimeter 16 to the deepest point of the edge of the notch when measured from the imaginary perimeter 16, where the line is perpendicular to the tangent line which passes through the point on the imaginary perimeter 16. The opening of each notch of the plurality of notches that are defined by the cross-sectional geometry 14 can be characterized with reference to the number of degrees of the rotating 360 degrees that define a circle . Accordingly, the first notch 28 includes a first leading edge 40 and a first trailing edge 42 that are spaced apart by a first rotary opening distance 44 of the notch, which as previously noted can be measured in terms of the degrees. The second groove 30 includes a second leading edge 46 and a second trailing edge 48 that are spaced apart by a second rotary opening distance 50 from the groove. The third notch 32 includes a third leading edge 52 and a third trailing edge 54 that are spaced apart by a third rotary opening distance 56 from the notch. It is understood that the leading and trailing edges referred to herein are not necessarily well-defined points or angles and that the edges in effect may be rounded as a result of use or abrasion or as a result of manufacturing methods or conditions. The outer edge of the geometry of the cross section 14 between each of the notches of the plurality of notches, can be characterized with reference to the number of degrees of the 360 degrees rotating defining a circle. Accordingly, the first leading edge 40 of the first groove 28 and the second trailing edge 48 of the second groove 30 are spaced apart by a first rotary distance 58. The second leading edge 46 of the second groove 30 and the third trailing edge 54 of the third groove 32 are spaced apart by a second rotary distance 60. The third leading edge 52 of the third groove 32 and the first trailing edge 42 of the first groove 28 are spaced apart by a third rotary distance 62. In the movement a along the imaginary perimeter 16 in a counterclockwise direction, the trailing edge of a notch, for example, the first trailing edge 42 of the first notch 28, is first encountered followed by the encounter of the first leading edge of the notch, for example the leading edge 40 of the first notch 28. Next, the second trailing edge 48 of the second notch 30 is found, followed by the encounter of the second leading edge 46 of the second notch 30 and, again, the third trailing edge 54 of the third groove 32 is found followed by the meeting of the third leading edge 52 of the third groove 32 and back to the start at the first trailing edge 42. The imaginary perimeter 16 starting at a point such as the first trailing edge of the groove. the first notch 28 and ending at the same point, represents 360 degrees. Accordingly, the sum of the first rotational distance 44 of notch opening, the second rotational distance 50 of the notch opening, the third rotary opening distance 56 of the notch, the first rotational distance 58, the second rotational distance 60, and the third rotating distance 62, is 360 degrees. A cross section of another embodiment of the invention is presented in Figure 3, which shows a cross-sectional view of an asymmetric shape 100 of five notches. The asymmetric shape 100 of five notches has a cross sectional geometry 102 defined in part by an imaginary perimeter 104, which may have any configuration or suitable shape, but as shown in Figure 3, the imaginary perimeter 104 approaches a circle having an axis 106. The imaginary perimeter 104 is further defined having a diameter 107 and a dividing line. imaginary 108 passing through the axis 106. The imaginary division line 108 is provided for, or otherwise divided, the cross-sectional geometry 102 into an upper end or half 110 and a lower or half end 112. The geometry of cross section 102 defines a plurality of notches that include the first groove 114, the second groove 116, the third groove 118, the fourth groove 120 and the fifth groove 122. The first groove 114, the second groove 116, the third groove 118. , the fourth groove 120, and the fifth groove 122 are respectively defined by a depth 124 of the first groove, the depth 126 of the second groove, the depth 128 of the third groove ca, the depth 130 of the fourth notch, and the depth 132 of the fifth notch. The depth of the notch is the shortest distance of a line from a point on the imaginary perimeter 104 to the deepest point of the notch edge when measured from the imaginary perimeter 104, where the line is perpendicular to the tangent line it passes through the point on the imaginary perimeter 104.

The opening of each notch of the plurality of notches that are defined by the geometry of the cross section 102, can be characterized with reference to the number of degrees of the 360 rotational degrees that define a circle. Accordingly, the first notch 114 includes a first leading edge 138 and a first trailing edge 140 that are spaced apart by a first rotary opening gap 142 of the notch, which can be measured as previously noted in terms of degrees. The second groove 116 includes a second leading edge 144 and a second trailing edge 146 that are spaced apart by a second rotary opening distance 148 from the groove. The third groove 118 includes a third leading edge 150 and a third trailing edge 152 that are spaced apart by a third rotary opening distance 154 of the groove. The fourth groove 120 includes a fourth leading edge 156 and a fourth trailing edge 158 that are spaced apart by a fourth rotary opening distance 160 of the groove. The fifth notch 118 includes a fifth leading edge 162 and a fifth trailing edge 164 that are spaced apart by a fifth rotational distance 166 of opening the notch. The outer edge of the cross-sectional geometry 102 between each of the notches of the plurality of notches, can be characterized by reference to the number of degrees of the 360 degrees rotating defining a circle. Accordingly, the first leading edge 138 of the first groove 114 and the second trailing edge 146 of the second groove 116 are spaced apart by a first rotary distance 168. The second leading edge 144 of the second groove 116 and the third trailing edge 152 of the third groove 118 are spaced apart by a second rotary distance 170. The third leading edge 150 of the third groove 118 and the fourth trailing edge 168 of the fourth groove 120 are spaced apart by a third rotary distance 172. The fourth leading edge 156 of the fourth groove 120 and the fifth trailing edge 164 of the fifth groove 122 are spaced apart by a fourth rotary distance 174. The fifth leading edge 162 of the fifth groove 122 and the first trailing edge 140 of the first groove 114 are spaced apart far by a fifth rotating distance 176. In the movement along the imaginary perimeter 104 in a direction in the reverse direction of the hands of the clock, the trailing edge of a notch, for example the first trailing edge 140 of the first groove 114, is first encountered followed by the meeting of the first leading edge of the same notch, for example the leading edge 138 of the first notch 114. Next, the second trailing edge 146 of the second groove 116 is found, followed by the encounter of the second leading edge 144 of the second groove 116. Next, the third trailing edge 152 of the third groove 118 is found, followed by the meeting of the third leading edge 150 of the third groove 118. Next, the fourth back edge 168 of the fourth groove 120 is found followed by the meeting of the fourth leading edge 156 of the fourth groove 120. Next, the fifth rear edge 164 of the fifth groove 122 is found followed by the meeting of the fifth leading edge 162 of the fifth groove 122 and then back to the start in the first b back order 140. The imaginary perimeter 104 starting at a point such as the first trailing edge of the first notch 114 and ending at the same point, represents 360 degrees. Accordingly, the sum of the first rotational distance 142 of notch opening, the second rotary opening distance 148 of the notch, the third rotary opening distance 154 of the notch, the fourth rotary opening distance 160 of the notch, the fifth rotational distance 166 of opening the notch, the first rotational distance 168, the second rotational distance 170, the third rotational distance 172, the fourth rotational distance 174, and the fifth rotational distance 176, is 360 degrees. It should be understood that the three-notch shape and the five-notch shape described above with respect to the figures are provided only as illusive examples of certain embodiments of the invention. It is therefore understood that the multiple notch shape of the invention may also include shapes having four notches or six or more notches, as long as the shapes satisfy the asymmetry requirement and other geometric properties as described herein. The spacing of the notches, notch depths, notch opening rotary distances and rotating distances may vary significantly and are not necessarily limited to the relative dimensions and geometries that are shown in the figures of this specification. The shaped particles of the invention can be prepared by any suitable method or means known to those skilled in the art using any material that can be suitably formed into a shaped particle as defined herein. Suitable materials that can be used in forming the shaped particle include, for example, materials or compounds or components that are typically used in the formation of catalyst systems or compositions or which, in combination with other components, form catalyst systems or compositions. . Methods of forming the shaped particles can include, for example, extrusion methods, molding methods and methods of forming pills or tabletting methods. When the shaped particles are used in the formation or preparation of a catalyst system, they can be formed from typical catalyst support materials, such as porous inorganic oxides, which can include any refractory oxide material having properties suitable for use as the support component of a system or catalyst composition. Examples of suitable, porous refractory oxide materials, possible, include silica, magnesia, silica-titania, zirconia, silica-zirconia, titania, silica-titania, alumina, silica-alumina, and alumino-silicate. Alumina can be of various forms, such as alpha alumina, beta alumina, gamma alumina, delta alumina, eta alumina, theta alumina, boehmite, or mixtures thereof. When the shaped particle comprises a support material, the catalytic materials can be further introduced into the particle formed by any of the known methods for incorporating catalyst components into a shaped catalytic support material, such as by standard impregnation methods. Also, the catalyst components can be co-mixed or co-ground, with the support material prior to the formation of the shaped particle to provide the shaped catalyst particle.

An especially important embodiment of the invention is a dehydrogenation catalyst system based on iron oxide which is in the form of the shaped particles as described here. This is because the dehydrogenation reactions, particularly the dehydrogenation of ethylbenzene to styrene, can be sensitive to the pressure and flow conditions of the reactor, and the shaped iron oxide catalyst system of the invention, can. provide a reduced pressure drop across a bed of the shaped catalyst system when compared to other forms of the prior art, and can provide improved flow characteristics through the bed. The shaped iron oxide catalyst system of the invention comprises iron oxide. The iron oxide of the dehydrogenation catalyst can be in any form and can be obtained from any source or by any method that provides an iron oxide material suitable for use in a dehydrogenation catalyst based on iron oxide. A particularly desirable iron oxide-based dehydrogenation catalyst includes potassium oxide and iron oxide. The iron oxide of the dehydrogenation catalyst based on iron oxide, can be in a variety of forms including any one or more of the iron oxides, such as, for example, yellow iron oxide (goethite, FeOOH), black iron (magnetite, Fe304), and red iron oxide (hematite, Fe203), including synthetic hematite or regenerated iron oxide, or it can be combined with potassium oxide to form potassium ferrite (K2Fe204), or it can be combined with potassium oxide to form one or more of the phases containing both iron and potassium as represented by the formula (K20) x- (Fe203) and. Typical iron oxide-based dehydrogenation catalysts comprise from 10 to 100 weight percent of iron, calculated as Fe203, and up to 40 weight percent of potassium, calculated as K20. The dehydrogenation catalyst based on iron oxide may further comprise one or more promoter metals which are usually in the form of an oxide. These promoter metals can be selected from the group consisting of Se, Y, La, Mo, W, Cs, Rb, Ca, Mg, V, Cr, Co, Ni, Mn, Cu, Zn, Cd, Al, Sn, Bi , rare earth metals and mixtures of any two or more thereof. Among the promoter metals, those selected from the group consisting of Ca, Mg, Mo, W, Ce, La, Cu, Cr, V, and mixtures of two or more thereof are preferred. Still more preferred are Ca, Mg, W, Mo, and Ce. Descriptions of typical, suitable, iron oxide-based dehydrogenation catalyst compositions are found in the patent publications including U.S. Patent Publication. No. 2003/0144566 Al; the U.S. patent No. 5,689,023; the U.S. patent No. 5,376,613; the U.S. patent No. 4,804,799; the U.S. patent No. 4,758,543; the U.S. patent No. 6,551,958 Bl; and EP 0,794,004 Bl. The formed iron oxide-based dehydrogenation catalyst, which comprises iron oxide and, preferably, also comprising potassium oxide, in general, can be prepared by combining the components of an iron-containing compound and a potassium-containing compound. and forming these components to form shaped particles followed by the calcination of the shaped particles. The compounds containing promoter metals can also be combined with the iron-containing and potassium-containing components. The formed iron oxide-based dehydrogenation catalyst can comprise from 10 to 90 weight percent iron oxide, calculated as Fe203 and based on the total weight of the iron oxide-based catalyst, formed. The dehydrogenation catalyst based on iron oxide, formed, may further comprise from 5 to 40 weight percent of potassium oxide, calculated as K20 and based on the total weight of the iron oxide-based catalyst, formed. The preferred concentration of iron oxide in the shaped iron oxide dehydrogenation catalyst, formed, is in the range of 20 to 85 weight percent, and 30 to 80 weight percent is even more preferred. The preferred concentration of potassium oxide in the formed iron oxide based catalyst is in the range of 10 to 35 weight percent, and 15 to 30 weight percent is even more preferred. The catalyst components can be formed in the shaped particle as described herein by any suitable method. A preferred method of manufacturing the iron oxide-based dehydrogenation catalyst is to mix the catalyst components together with water or a plasticizer, or both, and form an extrudable paste from which the extruded materials having the desired geometry are formed. . The extruded materials are then dried and calcined. The calcination is preferably carried out in an oxidizing atmosphere, such as air, and at rising temperatures of up to 1200 ° C, but preferably from 500 ° C to 1100 ° C, and, even more preferably, from 700 ° C to 1050 ° C. In order to provide the geometry of the desired particle and the required weight loading of the particle or catalyst formed from multiple notches, the shaped particle must have at least three notches, and may have on the scale upwards as much as seven or eight notches or even more notches depending on the size of the shaped particle and the amount of load of the weight required to provide the desired function. Accordingly, in broad terms, the shaped particle of the invention can have from 3 to about 10 notches, with each notch characterized in that it has a ratio of the depth to the diameter of the notch in the range from about 0.075: 1 to about 0.6: 1, a rotary distance of notch opening (?) In the range from about 5 to about 70 degrees, a rotating distance (?) In the range from about 20 to about 115 degrees, and a length ratio with with respect to the diameter in the range from about 0.5 to about 2. In absolute terms, the nominal diameter of the shaped particle can be in the range from 2 or 3 millimeters (mm) up to 15 or 20 mm. Preferably, the nominal diameter of the shaped particle is in the range from 3 mm to 10 mm, and, even more preferably, the nominal diameter is in the range from 3 mm to 8 mm. To provide the desired weight load, it may also be desirable that the cross section of the shaped particle have a geometry wherein the ratio of the cross-sectional area of the end or upper half of the shaped particle to the cross-sectional area of the end or lower half of the shaped particle, is in the range from 1.1: 1 to 4: 1. The terms "upper end" and "lower end" are defined in the above description with respect to the figures. It is preferred that the ratio of the cross-sectional area of the upper end or half of the shaped particle to the cross-sectional area of the lower end or half of the shaped particle is in the range from 1.25.1 to 3: 1, and, it is even more preferred that the ratio be in the range from 1.5: 1 to 2.5: 1. It is understood here that in the manufacture of the shaped particles, there are normal variations in the dimensions of the final manufactured product and that the dimensions of the shaped particles of the invention, manufactured, will vary within the normal manufacturing tolerances. The variations will be more pronounced depending on the method by which the formed particle is manufactured. For example, the particles made by the extrusion methods tend to have less uniformity than the particles made by the conversion methods in pills. And, although the cross section of the form of the invention has been described with reference to an imaginary circular perimeter about an axis, it should be understood that the shape of the cross section may deviate from a circle and may still include elongated cross sections, provided that the cross section is asymmetric and includes the other required features of the invention described therein. Also, the notches as shown in the figures thereof, reflect a "V" shaped groove formed by two straight edges that intersect at a point to form a well-defined angle. Although this geometry is a preferred embodiment, it is generally understood that the notches can not be well defined and that they can deviate somewhat from the "V" -shaped notches shown. For the three-notch mode of the shaped particle, the ratio of the depth to the diameter of the notch may be in the range from 0.075: 1 to 0.5: 1, preferably, from 0.125: 1 to 0.4: 1, and, even more preferably, from 0.15: 1 to 0.375: 1. The rotational opening distance of the notch may be in the range from 10 ° to 60 °, preferably from 15 ° to 50 °, and, even more preferably, from 20 ° to 40 °. The rotating distance can be in the range from 60 ° to 110 °, preferably from 70 ° to 105 °, and even more preferably from 80 ° to 100 °. The ratio of the length to the diameter of the shaped particle of three notches may be in the range of from about 0.5 to about 3.5, preferably from 0.7 to 3.2, and, even more preferably, from 1 to 3. It is common to have aim a ratio of the length to the diameter of about 2, but the result may vary significantly depending on the method and the manufacturing conditions used to manufacture the shaped particle. conformed. For the five-notch mode of the shaped particle, the ratio of the depth to the diameter of the notch may be in the range from 0.075: 1 to 0.5: 1, preferably, from 0.125: 1 to 0.4: 1, and, even more preferably, from 0.15: 1 to 0.375: 1. The rotational opening distance of the notch can be in the range from 10 ° to 50 °, preferably from 15 ° to 40 °, and, even more preferably, from 20 ° to 35 °. The rotating distance can be in the range from 29.5 ° to 70 °, preferably from 35 ° to 65 °, and even more preferably from 40 ° to 60 °. The ratio of the length to the diameter of the shaped particle of five notches may be in the range of from about 0.5 to about 3.5, preferably from 0.7 to 3.2, and, even more preferably, from 1 to 3. It is common to have aim a ratio of the length to the diameter of about 2, but the result may vary significantly depending on the method and the manufacturing conditions used to manufacture the shaped particle. The following table 1 presents in tabular form several of the dimensions of the shaped particles of 3, 5 and 7 notches of the invention.

Table 1. Wide, intermediate, and narrow, representative intervals for the geometrical dimensions of the asymmetrically shaped particle of multiple notches.

As noted above, the preferred use of the shaped particles of the invention is as a dehydrogenation catalyst system based on iron oxide. The formed iron oxide-based catalyst particles are placed or loaded into a reactor vessel to form a so-called packed bed of the shaped catalyst particles, with the packed bed having a depth inside the reactor vessel. The reactor vessel is equipped with a reactor feed inlet to receive a dehydrogenation raw material and an outlet for the reactor tributaries to extract a dehydrogenation reaction product. A dehydrogenation feed is passed through the catalyst bed to thereby contact the dehydrogenation feed with the formed, iron oxide-based dehydrogenation catalyst particles contained within the catalyst bed. This contact of the dehydrogenation feed with the formed iron oxide-based dehydrogenation material is carried out under suitable conditions of the dehydrogenation reaction. The dehydrogenation feed may be any suitable feed and, more particularly, may include any hydrocarbon that is dehydrogenatable. Examples of dehydrogenatable hydrocarbons include substituted benzene compounds, such as ethylbenzene, isoamylenes, which can be dehydrogenated to isoprenes, and butenes, which can be dehydrogenated to butadiene. The preferred dehydrogenation feed comprises ethylbenzene, which can be dehydrogenated to styrene. The dehydrogenation feed may also include other components, including diluents. The dehydrogenation conditions can include an inlet temperature of the dehydrogenation reactor in the range from about 500 ° C to about 1000 ° C, preferably, from 525 ° C to 750 ° C, and, even more preferably, from 550 ° C up to 700 ° C. Accordingly, the first temperature of the dehydrogenation catalyst bed can vary from about 500 ° C to about 1000 ° C, more specifically, from 525 ° C to 750 ° C, and, more specifically, from 550 ° C to 700 ° C. . It is recognized, however, that in the dehydrogenation of ethylbenzene to styrene, the reaction is endothermic. When such a dehydrogenation reaction is carried out, it can be done either isothermally or adiabatically. In the case where the dehydrogenation reaction is carried out adiabatically, the temperature through the dehydrogenation catalyst bed, between the inlet of the dehydrogenation reactor and the dehydrogenation reactor outlet, can be reduced by as much as 150 ° C, but , more typically, the temperature can be reduced from 10 ° C to 120 ° C. The reaction pressure is relatively low and can vary from vacuum pressure up to approximately 172 kPa (25 psia). To carry out the dehydrogenation reaction of ethylbenzene, it is better to carry out the reaction under pressure conditions as low as possible, for example from 34 kPa (5 psia) to 138 kPa (20 psia). In this case, the use of the shaped catalyst particles of the invention can be particularly beneficial by providing a desired, low pressure reaction condition. The space velocity per hour of the liquid (LHSV for its acronym in English) should be in the range from about 0.01 h_1 to about 10 h_1, and preferably, from 0.1 h_1 to 2 h "1. When used here, the term" speed per hour of liquid "is defined as the volumetric flow rate of the liquid of the dehydrogenation feed, for example, ethylbenzene, measured under normal conditions (ie, 0 ° C and an absolute bar), divided by the volume of the catalyst bed, or the total volume of the catalyst beds if there are 2 or more catalyst beds. When styrene is being manufactured by the dehydrogenation of ethylbenzene, it is generally desirable to use steam as a diluent, usually in a molar ratio of vapor to ethylbenzene in the range of 0.1 to 20. The steam can also be used as a diluent with other hydrogenatable hydrocarbons. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (9)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property. A shaped particle, characterized in that it has a geometry that includes a length and a cross-sectional geometry in at least one point along the length, wherein the cross-sectional geometry is defined by an asymmetric shape having a line imaginary division for an upper end, having a cross-sectional area of the upper end and a lower end, having a cross-sectional area of the lower end, wherein the cross-sectional area of the upper end is greater than the area of cross section of the lower end, wherein the cross section geometry is further divided by a perimeter of the circle having a diameter and a center through which the imaginary division line passes; wherein the cross-sectional geometry defines a plurality of notches wherein each notch of the plurality of notches is punctuated by a depth of the notch, a leading edge and a trailing edge, with the leading edge and the trailing edge spaced apart by a notch. rotating opening distance of the notch; wherein the leading edge of each notch of the plurality of notches is spaced away from the trailing edge of an adjacent notch by a rotating distance; and wherein the sum of the total rotational distances of opening of the notch and all of the rotational distances of the cross-section geometry is 360 °.
2. 2. A shaped particle according to claim 1, characterized in that each notch of the plurality of notches is defined by a ratio of the depth with respect to the diameter of the notch in the range from 0.075 to 0.6: 1; wherein each rotary opening distance of the notch is in the range of 10 ° to 70 °, and wherein each rotating distance is in the range of 20 ° to 115 °.
3. 3. A shaped particle according to claim 2, characterized in that the depth of the notch, of each notch of the plurality of notches, is defined as the linear distance of a line from a point of the perimeter on the circular perimeter to a point of the depth at the deepest point of the respective notch within the cross section geometry and where the line is perpendicular to the tangent line passing through the point of the perimeter on the circular perimeter.
4. A shaped particle according to claim 3, characterized in that the plurality of notches includes: a first notch having a depth of the first notch, a first leading edge and a first trailing edge, with the first leading edge and the first rear edge spaced apart by a first rotational distance of notch opening; a second notch having a second depth of the notch, a second leading edge and a second trailing edge, with the second leading edge and the second trailing edge spaced apart by a second rotational distance of aperture from the notch; a third notch having a third depth of the notch, a third leading edge and a third trailing edge, with the third leading edge and the third trailing edge spaced apart by a third rotational distance of opening the notch; wherein the first leading edge of the first notch is spaced apart from the second trailing edge of the second notch by a first rotational distance; wherein the second leading edge of the second groove is spaced apart from the third trailing edge of the third groove by a second rotary distance; and wherein the third leading edge of the third groove is spaced apart from the first trailing edge of the first groove by a third rotational distance.
5. 5. A shaped article according to claim 4, characterized in that the first notch has a ratio of the depth to the diameter of the first notch in the range from 0.1: 1 to 0.5: 1; wherein the first rotational opening distance of the notch is in the range of 10 ° to 60 °; wherein the first rotating distance is in the range from 60 ° to 110 °; wherein the second notch has a ratio of the depth to the diameter of the second notch in the range from 0.1: 1 to 0.5: 1; wherein the second rotational opening distance of the notch is in the range of 10 ° to 60 °; wherein the second rotating distance is in the range of 60 ° to 110 °; wherein the third notch has a ratio of the depth- with respect to the diameter of the third notch in the range from 0.1: 1 to 0.5: 1; wherein the third rotational opening distance of the notch is in the range of 10 ° to 60 °; and wherein the third rotating distance is in the range of 60 ° to 110 °.
6. A shaped article according to claim 3, characterized in that the plurality of notches include: a first notch having a depth of the first notch, a first leading edge and a first trailing edge, with the first leading edge and the first rear edge spaced apart by a first rotational distance of notch opening; a second notch having a depth of the second notch, a second leading edge and a second trailing edge, with the second leading edge and the second trailing edge spaced apart by a second rotational opening distance of the notch; a third notch having a depth of the third notch, a third leading edge and a third trailing edge, with the third leading edge and the third trailing edge spaced apart by a third rotational distance of opening the notch; a fourth notch having a depth of the fourth notch, a fourth leading edge and a fourth trailing edge, with the fourth leading edge and the fourth trailing edge spaced apart by a fourth rotational distance of opening the notch; a fifth notch having a depth of the fifth notch, a fifth leading edge and a fifth trailing edge, with the fifth leading edge and the fifth trailing edge spaced apart by a fifth rotational distance of notch opening; wherein the first leading edge of the first notch is spaced apart from the second trailing edge of the second notch by a first rotational distance; wherein the second leading edge and the second groove are spaced apart from the third trailing edge of the third groove by a second rotational distance; and wherein the third leading edge of the third groove is spaced away from the fourth rear edge of the fourth groove by a third rotating distance; wherein the fourth leading edge of the fourth groove is spaced away from the fifth trailing edge of the fifth groove by a fourth rotating distance; and wherein the fifth leading edge of the fifth groove is spaced apart from the first trailing edge of the first groove by a fifth rotating distance.
7. 7. A shaped article according to claim 6, characterized in that the first notch has a ratio of the depth to the diameter of the first notch in the range from 0.075: 1 to 0.5: 1; wherein the first rotational opening distance of the notch is in the range of 10 ° to 50 °; wherein the first rotating distance is in the range from 29.5 ° to 70 °; wherein the second notch has a ratio of the depth to the diameter of the second notch in the range from 0.075: 1 to 0.5: 1; wherein the second rotational opening distance of the notch is in the range from 10 ° to 50 °; wherein the second rotating distance is in the range of 29.5 ° to 110 °; wherein the third notch has a ratio of the depth to the diameter of the third notch in the range from 0.075: 1 to 0.5: 1; wherein the third rotational opening distance of the notch is in the range of 10 ° to 50 °; and wherein the third rotating distance is in the range of 29.5 ° to 70 °; wherein the fourth notch has a ratio of the depth to the diameter of the third notch in the range from 0.075: 1 to 0.5: 1; wherein the fourth rotational opening distance of the notch is in the range of 10 ° to 50 °; and wherein the fourth rotating distance is in the range of 29.5 ° to 70 °; wherein the fifth notch has a ratio of the depth to the diameter of the fifth notch in the range from 0.075: 1 to 0.5: 1; wherein the fifth rotating opening distance of the notch is in the range from 10 ° to 50 °; and wherein the fifth rotating distance is in the range of 29.5 ° to 70 °.
8. 8. A shaped particle according to any of claims 1-7, characterized in that the shaped particle is a catalyst system based on iron oxide, comprising iron oxide.
9. 9. A dehydrogenation process, characterized in that it comprises: contacting under the conditions of a hydrogenation reaction, a dehydrogenation feed with any of the formed iron oxide-based catalyst systems, according to claim 8.