APPARATUS AND METHOD FOR EXAMINING HETEROGENEOUSLY CATALYZED REACTIONS

Abstract

The invention relates to an apparatus for analyzing heterogeneously catalyzed reactions comprising at least one reactor (3) through which a particulate catalyst flows and at least one reactant feed, wherein arranged downstream of each reactor (3) is a separation apparatus (17) for separating the particulate catalyst from a reaction product comprising condensable gases and arranged downstream of the separation apparatus (17) is a liquid separator (31) for separating liquid constituents from the reaction product, wherein the liquid separator (31) comprises a metallic tube (103) and a deflection body (119), wherein the metallic tube (103) is closed at its ends and the deflection body (119) is accommodated in the metallic tube (103) and the metallic tube (103) comprises a side feed (135) at a first end (105) and a gas outlet (113) at a second end (107) and the gas outlet (113) is connected to at least one sample vessel (37). The invention further relates to a process for analyzing heterogeneously catalyzed reactions in the apparatus.

Claims

1. An apparatus for analyzing heterogeneously catalyzed reactions comprising at least one reactor through which a particulate catalyst flows and at least one reactant feed, wherein arranged downstream of each reactor is a separation apparatus for separating the particulate catalyst from a reaction product comprising condensable gases and arranged downstream of the separation apparatus is a liquid separator for separating liquid constituents from the reaction product, wherein the liquid separator comprises a metallic tube and a deflection body, wherein the metallic tube is closed at its ends and the deflection body is accommodated in the metallic tube and the metallic tube comprises a side feed at a first end and a gas outlet at a second end and the gas outlet is connected to at least one sample vessel.

2. The apparatus according to claim 1, wherein a catalyst reservoir container, from which the particulate catalyst is supplied to the reactor via a metering point, is present and/or a catalyst circuit is present, so that the catalyst separated in the separation apparatus may be returned to the metering point at the inlet into the reactor.

3. The apparatus according to claim 1, wherein the catalyst reservoir container and the separation apparatus have a functional connection provided with a differential pressure controller that actuates a continuously acting valve, wherein the outlet side of the continuously acting valve has either a connecting conduit to the separation apparatus or an exhaust air conduit and/or a pressure control valve is arranged in a functional connection between the liquid separator and the sample vessel.

4. The apparatus according to claim 1, wherein each sample vessel has an adjustable volume.

5. The apparatus according to claim 1 any of claims 1 to 4, wherein in an apparatus having one reactor, the one reactor is connected to at least two sample vessels and in an apparatus having more than one reactor each reactor is connected to at least one sample vessel.

6. The apparatus according to claim 1, wherein each reactor is a tubular reactor aligned at an angle in the range from 45° to 90° to the horizontal, wherein the particulate catalyst may flow through the tubular reactor from top to bottom or from bottom to top, wherein each tubular reactor preferably has a length in the range from 0.3 to 3 m and a diameter in the range from 3 to 100 mm.

7. The apparatus according to claim 1, wherein at least one reactor is a tubular reactor through which the particulate catalyst may flow from bottom to top, wherein the catalyst container is connected to the metering point via a pipe arc, wherein the pipe arc has a radius in the range from 25 to 75 mm.

8. The apparatus according to claim 1, wherein the reactor is a tubular reactor through which the particulate catalyst can flow from top to bottom, the separation apparatus is connected to a catalyst withdrawal apparatus, by means of which catalyst can be transferred into sample vessels arranged on a carousel, and the separation apparatus is further connected to a distributor channel to which a plurality of liquid separators are connected and wherein in each case one liquid separator is connected to one sample vessel for accommodating gaseous reaction product and/or wherein a plurality of liquid separators are connected to a plurality of sample vessels for accommodating the gaseous reaction product via a distributor channel.

9. The apparatus according to claim 8, wherein all liquid separators are connected to a plurality of sample vessels for accommodating the gaseous reaction product via a common distributor channel.

10. The apparatus according to claim 1, wherein the liquid separator comprises a droplet separator positioned between the deflection body and the gas outlet.

11. The apparatus according to claim 1, wherein the deflection body has a central axis and 1 to 20 deflection plates.

12. The apparatus according to claim 1, wherein the liquid separator comprises a feed conduit that is connected to the side feed and wraps helically around the metallic tube.

13. A process for analyzing heterogeneously catalyzed reactions, comprising: (a) adding liquid and/or gaseous reactants and a particulate catalyst to each of the reactors of an apparatus according to claim 1; (b) reacting the liquid and/or gaseous reactants in the presence of the particulate catalyst in each reactor to form a gaseous reaction product comprising condensable and/or liquid components; (c) separating the particulate catalyst from the gaseous reaction product comprising condensable and/or liquid components; (d) optionally cooling the gaseous reaction product comprising condensable and/or liquid components to condense the condensable components; (e) separating the condensed and/or liquid components in the liquid separator; (f) withdrawing a sample of the gaseous reaction product into the sample vessel after separation of the condensed and/or liquid components at a predetermined time, wherein a sample is withdrawn or pulsed withdrawal of samples is effected from the gaseous reaction product of each reactor at the predetermined time, wherein each withdrawal pulse introduces a sample of the gaseous reaction product into a new sample vessel; (g) analyzing the samples present in the sample vessels; (h) optionally weighing the liquid separators to determine the mass of the separated condensable and/or liquid components.

14. The process according to claim 13, wherein the particulate catalyst is supplied from a catalyst reservoir container, wherein the particulate catalyst in the catalyst reservoir container is preferably preheated.

15. The process according to claim 13, wherein the catalyst has a residence time in the reactor in the range from 0.1 to 10 s.

16. The process according to claim 13, wherein at least one liquid or gaseous reactant is added and on condition the process is performed in a configuration with downwardly transported pulverulent catalyst the mass ratio of catalyst to reactant is in the range from 1 to 100 or on condition the process is performed in a configuration with upwardly transported pulverulent catalyst the mass ratio of catalyst to reactant is in the range from 1 to 20.

17. The process according to claim 13, wherein the heterogeneously catalyzed reaction is a catalytic cracking reaction.

Description

[0139] In the figures:

[0140] FIG. 1 shows an apparatus according to the invention comprising a reactor traversed from top to bottom having a preheating zone for the catalyst,

[0141] FIG. 2 shows an apparatus according to the invention comprising a reactor traversed from top to bottom having two catalyst reservoir containers,

[0142] FIG. 3 shows an apparatus according to the invention comprising a reactor traversed from top to bottom having a plurality of sampling points,

[0143] FIG. 4 shows an apparatus according to the invention comprising a reactor traversed from bottom to top,

[0144] FIG. 5 shows a liquid separator,

[0145] FIG. 6 shows a sample vessel having an analysis unit in a first embodiment,

[0146] FIG. 7 shows a sample vessel with pressure control,

[0147] FIG. 8 shows an evaluation unit having a plurality of sample vessels,

[0148] FIG. 9 shows an evaluation unit having a plurality of sample vessels and a plurality of analysis units,

[0149] FIG. 10 shows the conversion of heavy oil as a function of the ratio of catalyst to reactant,

[0150] FIG. 11 shows the yield of gasoline as a function of conversion,

[0151] FIG. 12 shows the yield of propene as a function of conversion.

[0152] FIG. 1 shows an apparatus for analyzing heterogeneously catalyzed reactions comprising a reactor traversed from top to bottom and a preheating zone for the catalyst,

[0153] An apparatus 1 for analyzing heterogeneously catalyzed reactions comprises a reactor 3 through which a particulate catalyst flows. To this end the reactor 3 is preferably a tubular reactor aligned at an angle of 45° to 90° to the horizontal and particularly preferably at an angle of 90° to the horizontal as shown here. The reactor 3 is connected at its upper end to a catalyst reservoir container 5.

[0154] In order to be to perform endothermic reactions, for example catalytic cracking reactions, the particulate catalyst present in the catalyst reservoir container 5 is heated before it flows into the reactor 3. To this end, it is preferable to heat the catalyst in the catalyst reservoir container to a temperature at which the catalyst is not damaged. If this temperature is below the temperature at which the catalyst is intended to flow into the reactor, a preheating zone 7 in which the catalyst is further heated while flowing therethrough is additionally provided between the catalyst reservoir container 5 and the reactor 3. This preferably brings the catalyst to a temperature high enough to introduce the energy required for the endothermic reaction into the reactor. Especially in the case of catalytic cracking reactions the catalyst is to this end heated to a temperature in the range from 500° C. to 800° C. in the catalyst reservoir container 5 and further heated to a temperature in the range from 1000° C. to 1200° C. in the subsequent preheating zone 7.

[0155] To control the supply of the catalyst into the reactor 3 a first valve 9 is preferably arranged between the preheating zone 7 and the catalyst reservoir container 5. The first valve 9 is opened prior to commencement of an analysis, so that the catalyst can flow through the preheating zone 7 into the reactor 3. As soon as an experiment is terminated the first valve 9 is closed again. No further catalyst can flow into the reactor 3 and the reaction is thus also concluded.

[0156] In order to allow a reaction to be performed it is further necessary to supply the reactants necessary for the reaction. This is preferably achieved by supplying liquid reactant from a reactor reservoir container 11 to the reactor 3 via a suitable conveying means, for example a pump 13. The reactant may either be supplied directly at the upper end of the reactor 3 or, as shown in FIG. 1, via a connecting conduit 15 through which the particulate catalyst flows from the preheating zone 7 into the reactor 3. Alternatively or in addition to the liquid reactant from the reactant reservoir container 11 further reactant, in particular gaseous reactant or an inert gas, may also be supplied via a feed 12. The feed 12 preferably opens into a feed conduit to the reactor 3 before addition of the particulate catalyst to the reactor 3. The addition of an inert gas via the feed 12 is especially advantageous when the liquid reactant is to be brought into contact with the catalyst in finely atomized form. In this case the inert gas is used for atomizing the liquid reactant in a suitable injector.

[0157] After flowing through the reactor 3 the catalyst is is passed with a gaseous reaction product optionally comprising liquid and/or condensable components into a separation apparatus 17 for separation of the particulate catalyst.

[0158] To adjust the pressure in the reactor 3 the separation apparatus 17 is connected to the catalyst reservoir container 5 via a functional connection 19. Accommodated in the functional connection 19 is a differential pressure controller 21 which actuates a continuously active valve 23, wherein the outlet side of the valve 23 has a connection conduit 25 to the separation apparatus 17 and the inlet side of the valve 23 has a connection conduit 27 to the catalyst reservoir container.

[0159] The differential pressure controller 21 makes it possible to establish a defined pressure gradient between the catalyst reservoir container 5 and the reactor 3. The pressure gradient serves as a driving force for transferring the catalyst from the catalyst reservoir container 5 into the reactor 3. In addition, a pressure sensor 29 which captures the pressure at the inlet to the reactor is provided at the inlet to the reactor 3. The desired reaction pressure can be controlled using the pressure at the inlet to the reactor and the pressure gradient controlled via the differential pressure controller 21.

[0160] After separation of the particulate catalyst in the separation apparatus 17 the gaseous reaction product possibly still comprising liquid and/or condensable components is supplied to a liquid separator 31. In order to separate any catalyst particles still present in the gaseous reaction product the gaseous reaction product is preferably passed through a filter 33 upstream of the liquid separator 31.

[0161] In order also to separate condensable components in the liquid separator 31 said separator is preferably cooled. To this end the liquid separator may be accommodated in a cooling bath 35 for example. The cooling causes the condensable components to condense out of the gaseous reaction product and be separated in the liquid separator. After separation of the liquid and/or condensable components in the liquid separator 31 the gaseous reaction product is supplied to a sample vessel 37. If only a portion of the gaseous reaction product is to be analyzed it is also possible to withdraw the gaseous reaction product from the process before entry into the liquid separator via a first 3-way valve 39 or before entry into the sample vessel via a second 3-way valve 41. However, it is preferable to also connect a respective analysis unit to the first 3-way valve 39 or the second 3-way valve which makes it possible to determine properties, in particular the composition, of the gaseous reaction product.

[0162] FIG. 2 shows an apparatus according to the invention for analyzing heterogeneous catalyst reactions in a second embodiment.

[0163] In contrast to the embodiment shown in FIG. 1, the embodiment shown in FIG. 2 further comprises two catalyst reservoir containers 5, 5′. The use of the first catalyst reservoir container 5 and the second catalyst reservoir container 5′ makes it possible to perform the reaction over a longer period or with a larger amount of catalyst. In particular this makes it possible during withdrawal of particulate catalyst from one catalyst reservoir container 5, 5′ to fill the other catalyst reservoir container 5′, 5 with fresh catalyst and optionally preheat said container. Once a minimum fill level has been achieved in the first catalyst reservoir container 5, 5 it is then possible to switch over to the second catalyst reservoir container 5′, 5, so that catalyst can continue to flow into the reactor 3 continuously.

[0164] As well as the use of two catalyst reservoir containers 5, 5′, as shown here, it is also possible to employ more than two, for example three, four or more catalyst reservoir containers 5, 5′. The use of a plurality of catalyst reservoir containers 5, 5′ especially has the advantage that the individual containers may be made smaller, thus also allowing more rapid heating of the catalyst present therein.

[0165] If the catalyst in the catalyst reservoir container 5, 5′ can be sufficiently temperature controlled, in particular heated, as shown in FIG. 2, the additional preheating zone 7 may be dispensed with. However, it is also possible, as in the embodiment shown in FIG. 1, to provide each of the connecting conduits 15 from the catalyst reservoir container 5, 5′ with a preheating zone 7 to be able to further preheat the catalyst before entry into the reactor 3.

[0166] FIG. 3 shows an apparatus for analyzing heterogeneously catalyzed reactions which comprises a plurality of liquid separators and sampling points.

[0167] The supply of reactants, in particular catalyst, into the reactor 3, and the differential pressure control is in the embodiment shown in FIG. 3 carried out according to that shown in FIG. 2, wherein the connecting conduit here in each case accommodates a preheating zone 7 to further heat the catalyst before entry into the reactor 3.

[0168] In order to allow analysis of not only the gaseous reaction product the separation apparatus 17 for the particulate catalyst comprises a catalyst withdrawal apparatus 39. Said apparatus allows particulate catalyst to be withdrawn from the separation apparatus 17 and filled into sample vessels 41. In the embodiment shown the sample vessels 41 are arranged in a carousel 43 which can rotate onwards after the filling of a sample vessel 39, so that an empty sample vessel 41 can be passed to a catalyst withdrawal apparatus 39 and then filled with catalyst withdrawn from the separation apparatus 17.

[0169] The filled sample vessels 41 may then be withdrawn from the carousel 43 and the catalyst present therein may be analyzed. To this end the filled sample vessels 41 may either be manually withdrawn or the sample vessels 41 are automatically withdrawn and passed to corresponding analysis units which allow analysis for example of the composition of the catalyst or else deposits on the catalysts.

[0170] The gaseous reaction product optionally comprising liquid and/or condensable components is passed into a distributor channel 45, to which a plurality of liquid separators 31 are each connected via a valve 47. This allows for example performance of a plurality of consecutive reactions, wherein each reaction actuates a new liquid separator 31. The respective liquid separator 37 may be removed for example after conclusion of a reaction to allow determination of a liquid amount in the liquid separator. The liquid and/or condensable components may then be separated simultaneously during a further reaction in a further liquid separator 31. However, it is preferable to initially perform a plurality of reactions, where in each case a different liquid separator 31 is employed, and after conclusion of all reactions to analyze the liquid separated in each case.

[0171] The outlets of the liquid separator 31, through which the gaseous reaction product is withdrawn after separation of the liquid, open into a collector 49. A further distributor channel 51 or a multiway valve, by means of which a plurality of sample vessels 37 may be filled, is connected to the collector 49. The connection of a plurality of sample vessels 37 makes it possible for example to take a plurality of samples during a reaction in order to allow analysis of the progression of the reaction and reaction kinetics for example. However, it is further also possible according to the above-described use of the liquid separator 31 to perform a plurality of reactions consecutively and supply the gaseous reaction product of each reaction to a sample vessel 37. Once all reactions have concluded the gaseous reaction product of each reaction may be analyzed. It is alternatively also possible already to commence analysis of the gaseous reaction product from one sample vessel 37 while a further reaction whose gaseous reaction product is accommodated in a further sample vessel 37 proceeds.

[0172] It is particularly preferable when, as shown in FIG. 3, the reactor 3 is traversed from top to bottom and the separation apparatus 17 follows the reactor 3 in the flow direction. The separation apparatus is connected to a catalyst withdrawal apparatus 39 which is connected to a plurality of sample vessels 41, wherein the sample vessel 41 are preferably arranged on a carousel 43, so that the catalyst from the separation apparatus 17 can be transferred into the sample vessels 41, preferably into more than two sample vessels 41, in particular four or more sample vessel 41, using the catalyst withdrawal apparatus 39. The separation apparatus 17 is further also connected via a distributor channel 45, also known as a manifold, to a plurality of liquid separators 31, wherein the liquid separators 31 are particularly preferably utilized as collection vessels for the liquid. The distributor channel 45 is preferably connected to two or more liquid separators 31 and in particular to four more liquid separators 31. It is further particularly preferable when the liquid separators are functionally connected to a plurality of sample vessels 37, preferably two or more sample vessels 37 and in particular four or more sample vessels 37, wherein gaseous reaction product is collected in the sample vessels 37.

[0173] FIG. 4 shows an apparatus according to the invention for analyzing heterogeneously catalyzed reactions comprising a reactor traversed from bottom to top.

[0174] The reactor 3 shown in FIG. 4 differs from that of FIG. 1 by the flow direction of the particular catalyst. In order to achieve a uniform catalyst flow in the reactor 3 the catalyst reservoir container 5 is connected to the reactor 3 via a pipe arc 53 having a radius in the range from 25 to 75 mm. The addition of the reactant from the reactant reservoir container 11 or via the feed 12 may, as shown here, be effected in the pipe arc 53. It is alternatively also possible to already supply the reactant upstream of the pipe arc 53 or only shortly before entry into the reactor 3.

[0175] A liquid separator, as employed according to the invention in the apparatus 1, is shown in FIG. 5.

[0176] The liquid separator 31 comprises a metallic tube 103 having a first end 105 and a second end 107. In the embodiment shown here the metallic tube 103 is closed at its first end 105. The second end 107 is closed with a removable cover 109. The removable cover may secured by any means known to those skilled in the art, for example by screw-closure or the use of a bayonet closure or a clamp or clip. To achieve a gastight connection a sealing element 111 is accommodated between the metallic tube 103 and the removable cover 109. A suitable sealing element 111 is in particular an O-ring.

[0177] A gas outlet 113 is formed in the removable cover 109 . The gas outlet 113 is provided with a droplet separator 115 on the side pointing into the metallic tube 103 . The droplet separator 115 is preferably made of glass wool on which droplets are separated when the gases reaction product flows through the droplet separator 115 into the gas outlet 113.

[0178] The droplet separator 115 is held in its position in the cover 109 by an axis 117 of a deflection body 119. The deflection body 119 shown in FIG. 5 comprises three deflection plates 121. Other than three deflection plates 121, as shown here, the deflection body 117 may also have more or fewer deflection plates 121, for example 1 to 20 deflection plates 121, preferably 1 to 10 deflection plates 121 and in particular 3 to 6 deflection plates 121. The side 123 of each deflection plate 121, which points toward the first end 105 of the metallic tube 103, encloses an angle α of 90° with the axis 117 of the deflection body 119.

[0179] The side 125 of the deflection plates 121 that points toward the second end 107 of the metallic tube 103 encloses an angle β between 90° and 150° with the axis 117 of the deflection body 119, wherein the angle is preferably greater than 90°.

[0180] Each deflection plate 121 is configured such that a gap 127 of 0.05 to 1 mm in width is formed between the edge 129 of every deflection plate 121 and the inner wall 131 of the metallic tube 103.

[0181] The liquid separator 31 further comprises a feed conduit 133 through which the reaction product comprising liquid and/or condensable components is supplied to a side feed 135 in the metallic tube 103. The feed conduit 133 wraps helically around the metallic tube 103.

[0182] During operation the gaseous reaction product comprising liquid and/or condensable components flows into the feed conduit 133 and flows through the feed conduit 133 to the side feed 135, through which it flows into the inside of the metallic tube. Especially when the gaseous reaction product comprises condensable components the gaseous reaction product in the feed conduit 133 is cooled, so that the condensable components begin to condense and liquid droplets are formed. For cooling it is possible for example to introduce the entire liquid separator 31 into a cooling bath 35.

[0183] Once the gaseous reaction product has flowed into the inside of the metallic tube 103 it flows in the direction of the gas outlet 113. To reach the gas outlet 113 the gaseous reaction product must pass the deflection plates 121, wherein the gaseous reaction product flows through the gap 127. This leads to deflection and acceleration of the gas stream. After passing through the gap 127 the gas stream slows down and opens into the entire space above the deflection plate 121. This is repeated at each baffle 121. Due to their mass, the droplets that have formed in the gaseous reaction product are deposited on the side 123 of the deflection plates 121 that points in the direction of the first end 105 of the metallic tube 103. The droplets that are deposited on the deflection plates 121, the axle 117 and the inner wall 131 of the metallic tube agglomerate and flow towards the lower end 137 of the metallic tube 103. The liquid may be withdrawn from the lower end 137 of the metallic tube 103 through a liquid outlet 139.

[0184] In order to prevent gas from the liquid separator 31 being withdrawn through the liquid outlet 139 when the separation of the liquid is performed at elevated pressure or a pressure below ambient pressure the liquid outlet 139 may be sealed by a suitable valve 141. The valve 141 allows for example withdrawal of liquid at predetermined times or once a predetermined fill level has been achieved. If liquid is to be withdrawn once a predetermined fill level has been reached it is particularly preferable to employ a fill level sensor with which the fill level may be determined. To this end it is possible to employ either a fill level sensor which continuously measures the fill level in the lower portion 137 of the metallic tube 103 or a sensor which only provides a signal once a fill level at which the sensor comes into contact with liquid has been achieved. To withdraw the liquid from the liquid separator the valve 141 may be operated either manually or in automated fashion. If an automatic valve is employed it is particularly preferable if it closes once a predetermined lower fill level has been reached.

[0185] Especially if not all liquid components have been separated by the deflection body 119, remaining droplets are separated by the droplet separator 115 when the gaseous reaction product flows through the droplet separator 115 to the gas outlet 113.

[0186] If the liquid remains in the droplet separator 115 and the droplet separator 115 becomes saturated with liquid or the droplet separator 115 blocks the gas outlet 113 due to deposits it is necessary to replace the droplet separator 115. Saturation or clogging of the droplet separator 115 is detectable for example through an increasing pressure drop over the liquid separator or through a reduced gas flow.

[0187] To replace the droplet separator 115 the removable cover 109 is removed so that the droplet separator 115 is accessible and can be removed. The droplet separator 115 can then be removed from the cover 109 and cleaned or replaced with a new droplet separator 115.

[0188] Besides a removable cover 105 at the second end 107 of the metallic tube it is alternatively or in addition also possible to close the first end 105 of the metallic tube 103 with a removable cover.

[0189] FIG. 6 shows a sample vessel comprising an analysis unit in a first embodiment.

[0190] To allow analysis of the gaseous reaction product this is preferably collected in sample vessel 37. To this end the gaseous reaction product is introduced into the sample vessel 37 via a sample conduit 209 via a first valve 211.

[0191] In order to take a sample, the first valve 211 is opened. With the first valve 211 open gaseous reaction product can then flow into a sample chamber 215 in the sample vessel 37 via the sample conduit 209. As shown here, the sample chamber 215 is preferably delimited on one side by a piston 217 movable within the sample vessel 37. The piston 217 can be used to adjust the volume of the sample chamber 215 in the sample vessel 37. At the start of the sampling, the piston 217 is preferably in a first position in which the volume of the sample chamber 215 is at a minimum. With commencement of sampling, the piston 217 then moved in the direction of a second position in which the volume of the sample chamber 215 is at a maximum. As soon as the piston 217 has reached the second position or if the sampling is to be ended before the sample has reached the second position 217, the valve 211 is closed, so that no further gaseous reaction product can flow into the sample chamber 215 in the sample vessel 217.

[0192] The movement of the piston 217 can be assisted for sampling in that a pressure lower than the pressure of the gaseous reaction product is applied to the side of the piston 217 remote from the sample chamber 215. This simultaneously leads to suction of reaction mixture into the sample chamber 215. In order to apply the lower pressure to the side of the piston 217 remote from the sample chamber 215, it is possible, for example, for a gas conduit 219 on the side of the piston 217 remote from the sample chamber 215 to open into the sample vessel 37. In order to apply the lower pressure, the gas conduit 219 sucks gas out of the sample vessel, such that the piston 217 moves in the direction of its second position. As soon as the sampling is to be ended, the suction of the gas is ended.

[0193] The gaseous reaction mixture present in the sample chamber 215 is then sent to an analysis unit 221 in a next step. It is possible here to use any desired analysis unit with which the desired analyses on the gas mixture can be conducted. Customary analysis units are especially those with which the composition of the gaseous reaction product can be determined. In order to be able to supply the gaseous reaction product to the analysis unit 221, the analysis unit 221 is connected via a measurement conduit 223 to the sample chamber 215 in the sample vessel 37. In order to be able to close the measurement conduit 223, a second valve 225 is accommodated in the measurement conduit 223. During the sampling, the second valve 225 is closed.

[0194] In order to supply the sample to the analysis unit 221, the second valve 225 is opened. Then the piston 217 is moved in the direction of its first position, such that the gaseous reaction product present in the sample chamber 215 is forced out of the sample chamber 215 into the measurement conduit 223 by the movement of the piston 217 and supplied to the analysis unit 221 through the measurement conduit 223. The piston 217 can be moved either with a suitable drive or, as shown here, with the aid of pressurized gas which flows into the sample vessel via the gas conduit 219 and acts on the side of the piston 217 remote from the sample chamber 215. The pressure exerted on the piston 217 by the pressurized gas forces it in the direction of the sample chamber, such that the gaseous reaction product present in the sample chamber is forced into the measurement conduit 223. As soon as the piston 217 has reached its first position at which the volume of the sample chamber is at a minimum, the supply of pressurized gas is ended. For this purpose, a third valve 227 is preferably provided in the gas conduit 219. The supply of pressurized gas is ended by closing the third valve 227.

[0195] After the sample chamber 215 has been emptied completely, another sample can then be taken.

[0196] Especially in the case of a hot gaseous reaction product, it is advantageous when the sample vessel is heatable. For this purpose, preference is given to using an electrical heater 229. The electrical heating can be implemented, for example, by means of heating coils surrounding the sample vessel 37. Alternatively, it is also possible to use a heating jacket.

[0197] For control of the movement of the piston 217, position sensors are preferably provided. A first position sensor 231 detects whether the piston 217 is in the first position, and a second position sensor 233 whether the piston 217 is in the second position. The position sensors 231, 233 are especially utilized in order to control the movement of the piston by application of reduced pressure or elevated pressure. If a sample is taken, the removal of gas to generate a pressure below the pressure of the gaseous reaction product is ended when the second position sensor 233 detects that the piston 217 has reached its second position. Accordingly, the pressurized gas supply in the removal of the sample from the sample chamber 15 is ended when the first position sensor 231 detects that the piston 217 has reached its first position.

[0198] As an alternative to the above-described embodiment with pneumatic movement of the piston 217, it is also possible for the piston to be moved hydraulically. In this case, rather than a gas, a fluid is used, which is sucked out of the sample vessel 37 when the piston 217 is to move into the second position, and forced into the sample vessel 37 in order to move the piston into its first position.

[0199] As well as the pneumatically or hydraulically assisted movement of the piston, movement of the piston is alternatively also possible with the aid of a drive, for example with a step motor. When a step motor is used, it is directly also possible to detect the position of the piston, such that the position sensors 231, 233 can be dispensed with in this case. When a drive that does not permit determination of the piston position is used for piston, however, the use of the position sensors 231, 233 is advantageous in order to end the movement of the piston in the respective direction by stopping the drive as soon as the corresponding position sensor 231, 233 has detected the piston.

[0200] FIG. 7 shows a sample vessel with pressure control.

[0201] In order to facilitate sampling a vacuum pump 243 is provided in the embodiment shown in FIG. 7. The vacuum pump 243 can be used to apply a pressure lower than the pressure in the separator to the side of the piston 217 remote from the sample chamber 215. As a result, with the first valve 211 open, gaseous reaction product is sucked into the sample chamber 215. The vacuum pump 243 is especially advantageous when the reaction is performed under ambient pressure or a pressure below ambient pressure. When the reaction is performed at a pressure above ambient pressure, in general, one outlet to the environment is sufficient, since, in this case, the positive pressure of the gaseous reaction product forces the gaseous reaction product into the sample chamber 215 and moves the piston 217 upward. In order to prevent the piston from being forced upward too quickly, it is possible in this case either to provide the piston with a weight or preferably to insert a valve in the outlet to the environment that can be opened only to such an extent that the piston is raised at the desired speed. A construction as shown in FIG. 6 is sufficient for this purpose.

[0202] In order that the gaseous reaction product can also be withdrawn from the sample chamber 215, as described above, a positive pressure is then applied to the opposite side of the piston 217 from the sample chamber 215, such that the piston 217 is forced in the direction of the sample chamber 215 and hence the mixture present in the sample chamber 215 is guided out of the sample chamber 215 through the measurement conduit 223 to the analysis unit 221.

[0203] For control of the piston 217, in the embodiment shown in FIG. 7, a controllable valve 245 is accommodated in the gas conduit 219. For this purpose, the pressure is measured in the gas conduit 219 between the sample vessel 37 and the controllable valve 245, and the valve is controlled with a pressure regulator 247. When the pressure measured in the gas conduit 219 differs from the desired pressure, the controllable valve 245 is set correspondingly. The controllable valve 245 is opened further if if too low a pressure is measured, and closed further if too high a pressure is measured. If too low a pressure is measured, during the sampling, the piston 217 is moved too quickly into its second position and the volume of the sample chamber 215 is increased; when the piston 217 is moved into its first position, the piston 217 is moved too slowly and the gaseous reaction product present in the sample chamber 215 is guided too slowly from the sample chamber 215 into the analysis unit 221. If too high a pressure is measured, during the sampling, the piston 217 is moves too slowly, such that the sampling is not fast enough, or the pressure that acts on the piston 217 is even so high that it does not move and hence no sample is taken. When the piston 217 is moved into its first position, the effect of an excessively high pressure is excessively rapid movement in the first position, such that the gaseous reaction product is displaced too quickly from the sample chamber 215.

[0204] In order to analyze the progression of the reaction over a longer period or to take a plurality of separate samples from a plurality of consecutive reactions a plurality of sample vessels which can each consecutively accommodate one sample are connected to the sample conduit 209. This is shown by way of example in FIG. 8.

[0205] In order to allow consecutive withdrawal of a plurality of samples from the reactor, sample conduit 209 is connected to plurality of sample vessels 37 via a multiway valve 249. Instead of a multiway valve it is also possible, as shown in FIG. 3, to utilize a distributor channel 51 to which the sample vessels 37 are connected. A 3-way valve 251 may also be arranged upstream of the multiway valve 249. The 3-way valve 251 is utilized to establish a connection either from the liquid separator 31 to the sample vessels 37 or alternatively from the sample vessels 37 to the analysis unit 221. In order to be able to take a sample, the 3-way valve 251 is adjusted such that a connection from the liquid 31 the multiway valve 249 is open, and the connection for the multiway valve 249 to the analysis unit 221 is closed. The multiway valve 249 is then used to open the connection to the respective sample vessel 37 that is to be filled during the sampling. Accordingly, for the analysis of the samples present in the sample vessel 37, the 3-way valve 251 is connected such that the connection from the 3-way valve 251 to the analysis unit 221 is open and, by the multiway valve 249, the connection to the sample vessel 37 from which the desired sample is to be taken and guided to the analysis unit 221.

[0206] With the multiway valve 249, it is possible in a simple manner to successively take multiple samples by, after sampling into the sample vessel 37 has ended, switching over the multiway valve 249 and opening the connection to the next sample vessel 37. This can be repeated until samples are present in all sample vessels 37. Accordingly, it is then also possible to supply the samples from the individual sample vessels 37 successively to the analysis unit 221 by, in the course of sampling too, switching over the multiway valve 249 to a further sample vessel 37 as soon as a sample vessel 37 has been emptied. In order to assist the movement of the pistons 217 in the sample vessels, each sample vessel 237 is connected to a gas conduit 219 here too, such that - as described above for FIGS. 6 and 7 - the movement of the piston 217 can be assisted by application of pressure on the side remote from the sample chamber 215 or by application of a reduced pressure on the side remote from the sample chamber 215. In this case, it is possible to simultaneously exert the pressure on all pistons or simultaneously to apply reduced pressure to all pistons 217, since only in the sample vessel 37 to which the connection through the multiway valve 49 is open is it possible to move the piston 217 for accommodation of a sample or for emptying. In the other sample vessels, owing to the closed connection, a pressure equilibrium is established, which prevents the movement of the piston.

[0207] Here too, the third valve 227 is accommodated in the gas conduit 219 through which the gas is guided to assist the piston movement. The valve may be provided with a pressure gauge 252 in order thus to have control over whether a sample vessel 37 is currently being filled or emptied. In the case of a pressure below the reactor pressure, a sample vessel 37 is being filled, and, in the case of a pressure above the reactor pressure, the sample from a sample vessel 37 is being supplied to the analysis unit 221.

[0208] FIG. 9 shows a further evaluation unit having a plurality of sample vessels and a plurality of analysis units.

[0209] The embodiment shown in FIG. 9 differs from that shown in FIG. 8 by a second multiway valve 253 by means of which a plurality of liquid separators may be connected to the liquid vessels 37. In this case the multiway valve 253 can be used instead of the collector shown in FIG. 3. Via the second multiway valve 253 the gaseous reaction product passes into 3-way valve 251 and, via said valve, as per the embodiment in FIG. 8, to the multiway valve 249 and from there into the sample vessel 37 to which the connection has been opened. The multiway valve 249 then makes it possible to take a plurality of samples consecutively. It is alternatively also possible in the case of a plurality of consecutively performed reactions to take only one sample in each reactor. In this case, after the taking of a sample, both multiway valves 249, 253 are switched to open the connection from a further liquid separator 31 to a further sample vessel 37. This can be repeated until samples have been taken from all liquid separators and all sample chambers 215 contain a sample.

[0210] Unlike the embodiments described above for FIGS. 6 to 8, the analysis region comprises multiple analysis units 261, 265. For this purpose, multiple 3-way valves 259, 263 are accommodated in the measurement conduit 223. It is possible either for each 3-way valve 259, 263 to be used to open a connection to an analysis unit 261, 265 or for a connection to be opened to a downstream 3-way valve or an outlet 257. For example, it is possible first to switch the first 3-way valve 259 such that the gaseous reaction product is supplied to the first analysis unit 261. Subsequently, the first 3-way valve 259 is switched such that the gaseous reaction product is guided past the first analysis unit 261 to the second 3-way valve 263. The second 3-way valve 263 is there switched such that the gaseous reaction product is guided into the second analysis unit 265. If no sample is to be taken, both 3-way valves 259, 263 are switched such that the gaseous reaction product passes to the outlet 257. It is also possible here to guide a sample only to one analysis unit 261, 265 in each case, the analysis unit 261, 265 utilized being dependent on the analysis to be conducted. In addition, it is also possible, especially in the case of longer-lasting analyses, to supply a sample to the first analysis unit 261 and, while the sample is still being analyzed, a further sample from another sample vessel of the second analysis unit 265. If the analyses take a very long time, it is also possible for acceleration of the analyses to use further analysis units that can each be operated in parallel.

EXAMPLES

[0211] In order to provide an exemplary illustration of the process according to the invention a plurality of catalytic cracking reactions were investigated.

[0212] When performing the analyses an apparatus having a vertically oriented tubular reactor was employed, wherein a first series of experiments employed a construction as shown in FIG. 1 in which the catalyst flows from top to bottom and a second series of experiments employed a construction as shown in FIG. 4 in which the catalyst flows from bottom to top.

[0213] The reactor had a length of 1.7 m and an internal diameter of 9.5 mm. The analyses were performed at a reactor temperature of 530° C., wherein the reported temperature relates to the temperature at the outlet of the reactor.

[0214] To perform the experiments the catalyst was filled into the catalyst reservoir container. The catalyst employed was a pre-calcined E-Cat that had previously been sieved to remove coarse-grained particles having a size of 200 .Math.m or larger. The catalyst reservoir container employed here had an internal volume of 1 L. The catalyst reservoir container is provided with a heating apparatus, wherein the catalyst reservoir container has a conical outlet funnel in the lower portion which has a porous surface. The outer surface of the porous region is functionally connected to a gas feed. The supply of gas through the porous region makes it possible to store the catalyst in a fluidized state in the container. In the analyses performed here the catalyst was stored in the catalyst reservoir container at a temperature of 700° C.

[0215] The injection unit was initially calibrated to inject the oil employed as reactant into the reactor at a constant metering rate of 7 g/ min. The employed oil had a specific density of 0.9042 g/cm.sup.3, a sulfur content of 0.8% by weight, a UOPK factor of 11.94 and a CCR content of 0.19% by weight. The CCR content (Conradson carbon residue, also referred to as “Concarbon” or “CCR”) is a laboratory test used to characterize the coking tendency of an oil. Table 1 shows the fractions resulting from a distillation.

TABLE-US-00001 Composition of heavy oil by fractions Temperature [°C] Evaporated proportion [%] 329 10 385 30 423 50 471 70 525 90

[0216] To perform the catalytic cracking reactions the catalyst and the oil are brought into contact in the inlet region of the reactor, wherein in each case a cracking is performed at a previously specified ratio of catalyst to employed reactant (hereinbelow “catalyst to oil ratio”). The catalyst to oil ratio is adjusted by specifying and varying the metering rate of supplied catalyst, wherein the catalyst and the oil are passed through the reactor for a defined duration and transferred into the separation apparatus for the catalyst. The duration for passing the catalyst through the catalyst was chosen as 1 minute for each experiment. The residence time of the catalyst and the oil in the reactor was in the range from about 2 to 3 seconds.

[0217] A total of thirteen crackingd were performed with the fluidized bed reactor, wherein five crackings were performed in upwardly transported operation and eight crackings were performed in downwardly transported operation. Catalyst to oil ratios were in the range from 5.4 to 13.5 for analyses in downwardly transported operation and in the range from 9 to 15 for analyses in upwardly tansported operation. Accordingly the amounts of employed catalyst in the analyses in downwardly transported operation were in the range from 38 g to 95 g and in the analyses in upwardly transported operation were in the range from 63 g to 105 g. It should be noted here that the analyses in upwardly transported operation are limited in the catalyst to oil ratio by the fact that a portion of the transport energy for conveying the catalyst is provided by the cracking products. A catalyst to oil ratio in the range of 15 or 20 is iat the limit since otherwise insufficient amounts of gaseous products are present to drive the catalyst upwards. The crackings were performed at a pressure of 2.5 bar, wherein the pressure for the gaseous reaction product was controlled via the pressure control valve between the liquid separator and the sample vessel The catalyst is collected in the separation apparatus and the stripping/removal of the cracking products and unconverted reactants already begins during collection of the first portion of the catalyst inside the separation apparatus.

[0218] After conclusion of the cracking reaction the stripping of the volatile components on the catalyst collected in the separation apparatus is continued for a further duration of 10 minutes, wherein stripping was performed using a dry nitrogen stream at a flow rate of 1 liter per minute. The stripping gas was passed initially from the separation apparatus through the liquid separator and subsequently via a conduit provided with a control valve to a sample vessel. In the present case the sample vessel was configured such that a gas volume of 15 liters was able to be collected. After each experiment both the mass of the catalyst material collected in the separation apparatus and the amount of liquid collected in the liquid separator were determined by weighing. Furthermore, the amount of gas volume collected in the sample vessel was determined. The amount of coke deposited on the catalyst was also determined.

[0219] The experiments were evaluated by performing an analytical characterization of the liquids and gases by gas chromatography. The results of these analyses are shown in FIGS. 10 to 12, wherein measurement points for a reactor with catalyst flowing from top to bottom and for a reactor with catalyst flowing from bottom to top were in each case used to plot an approximation curve.

[0220] FIG. 10 shows the catalyst to oil ratio 301 on the abscissa and the conversion 303 on the ordinate. A reactor with catalyst flowing from bottom to top, represented by unshaded circles 305, achieves a slightly higher conversion than a reactor with catalyst flowing from top to bottom, represented by shaded rhombi 307, at identical catalyst to oil ratio. For the individual experiments, in each case only the catalyst to oil ratio was varied while the other process conditions (pressure, temperature and amount of inert gas) were kept constant.

[0221] The conversion shown in FIG. 10 is the yield of light cycle oil (LCO) obtained during fluid catalytic cracking based on the employed amount of heavy oil. Conversion refers to the sum of obtained gases, gasoline and coke, wherein gasoline is to be understood as meaning all components having a boiling point in the range from 28° C. to 216° C.

[0222] The higher conversion in the case of a catalyst 305 flowing from bottom to top is in particular a consequence of the longer residence time of the catalyst in the reactor. This results from the lower velocity at which the catalyst is transported upwards with the gases flowing through the reactor. In the case of a catalyst flowing from top to bottom the movement is in particular a consequence of the gravitational force. Both in the reactor with catalyst flowing from top to bottom and in the reactor with catalyst flowing from bottom to top, the catalyst and the reactants are supplied in cocurrent.

[0223] In FIG. 11 the yield of gasoline is reported as a function of conversion, wherein the conversion 303 is here shown on the abscissa and the yield of gasoline 309 on the ordinate. It is apparent that a reactor with catalyst 305 flowing from bottom to top achieves a lower yield of gasoline at higher conversion while a reactor with catalyst 307 flowing from bottom to top achieves a higher yield of gasoline at lower conversion. The conversion corresponds to that shown in FIG. 10 as a function of the catalyst oil ratio.

[0224] A similar result is also apparent from the yield of propene from the employed oil which is shown in FIG. 12. The yield 311, shown on the ordinate, is here defined as the yield of propene divided by the sum of the yield of propene and the yield of propane. Since propene is a value product, employed for example in the production of polypropylene, a highest possible yield of propene is desired.

[0225] Here too, it is apparent that a reactor with catalyst flowing from top to bottom 307 achieves a higher yield at lower conversion than a reactor with catalyst flowing from bottom to top 305.

[0226] The lower yields of gasoline and of propene in the reactor with catalyst flowing from bottom to top are also a consequence of the longer residence time. Once a maximum conversion to the corresponding products has occurred, a longer residence time results in a further reaction where the gasoline is cracked further to afford shorter-chain hydrocarbons and the propene is further hydrogenated to afford propane.

TABLE-US-00002 List of reference numerals 1 apparatus for analyzing heterogeneously catalyzed reactions 123 side pointing to first end 105 3 reactor 125 side pointing to second end 107 5, 5′ catalyst reservoir container 127 gap 7 preheating zone 129 edge 9 first valve 131 inner wall 11 reactant reservoir container 133 feed conduit 12 feed 135 side feed 13 pump 137 lower end 15 connecting conduit 139 liquid outlet 17 separation apparatus 141 valve 19 functional connection 207 outflow conduit 21 differential pressure controller 209 sample conduit 23 valve 211 first valve 25 connecting conduit to separation apparatus 215 sample chamber 27 connecting conduit to catalyst reservoir container 217 piston 29 pressure sensor 219 gas conduit 31 liquid separator 221 analysis unit 33 filter 223 measurement conduit 35 cooling bath 225 second valve 37 sample vessel 227 third valve 39 catalyst withdrawal apparatus 229 heater 41 sample vessel 231 first position sensor 43 carousel 233 second position sensor 45 distributor channel 243 pump 47 valve 245 controllable valve 49 collector 247 pressure regulator 51 distributor channel 249 multiway valve 53 pipe arc 251 3–way valve 103 metallic tube 252 pressure gauge 105 first end 253 second multiway valve 107 second end 255 common mixer 109 removable cover 257 outlet 111 sealing element 113 gas outlet 115 droplet separator 117 axis 119 deflection body 121 baffle plate