KR100807164B1 - Simplified plate channel reactor arrangement - Google Patents

Abstract

A method and apparatus for indirectly exchanging heat with a narrow channel in a heat exchangeable channel reactor zone uses a plate 17 comprising a partially perforated portion 16 to distribute and recover different fluids into various channels. The use of manifolds can be simplified or omitted. The present invention simplifies operation by directly communicating adjacent channels through perforations located at one or the other end of the channel. The arrangement of the present invention provides the advantage of making the heat exchange reactor arrangement more compact. The arrangement of the present invention simplifies the use of a single manifold at one end of the channel to facilitate catalyst loading and catalyst replacement in the reaction channel.

Description

Simplified plate channel reactor arrangement {SIMPLIFIED PLATE CHANNEL REACTOR ARRANGEMENT}

The present invention generally relates to a plate-type exchanger arrangement comprising a reaction zone and for indirectly heating the reaction zone with a heat exchange fluid.

In many industries such as the petrochemical and chemical industries, contacting a catalyst and a reaction fluid in a reactor under suitable temperature and pressure conditions results in a reaction between one or more reactants in the fluid. Most of these reactions generate or absorb heat to varying degrees and are therefore exothermic or endothermic. The heating or cooling effect associated with an exothermic or endothermic reaction has a positive or negative effect on the operation of the reaction zone. Negative effects may include, among other things, the production of defective products, inactivation of catalysts, generation of unwanted byproducts and, in extreme cases, damage to the reaction vessel and the piping connected thereto. More typically, the undesirable effects associated with temperature changes may reduce the selectivity or yield of products derived from the reaction zone.

The exothermic reaction process involves various feedstocks and products. Slightly exothermic processes include methanol synthesis, ammonia synthesis and conversion of methanol to olefins. Preparation of phthalic anhydride by oxidation of naphthalene or orthoxylene, production of acrylonitrile from propane or propylene, acrylic acid synthesis from acrolein, conversion of n-butane to maleic anhydride, methanolic carbonation by acylation The production and conversion of methanol to formaldehyde generally represents another class of overheating reactions. In particular, oxidation reactions are generally hyperpyrogenic. The exothermic nature of these reactions introduces cooling equipment into a number of reaction systems in process design. Those skilled in the art typically overcome the problem of exothermic heat generation using quench arrangements or heat exchange arrangements. Many documents describe indirect heat exchange methods between reaction zones and cooling media. The art currently relies mainly on tubular arrangements which comprise reactants and which indirectly contact the reactants with the cooling medium. The geometry of the tubular reactors has design constraints that require large reactors and large tube faces to increase heat transfer efficiency.

Another process application performs indirect heat exchange with thin plates that define channels. The channels alternately retain the heat transfer fluid in adjacent channels with the catalyst and reactants in one set of channels to indirectly heat or cool the reactants and catalyst. Heat exchange plates in such indirect heat exchange reactors may be flat or curved and may modify surfaces, such as corrugations, to increase the amount of heat transfer between the heat transfer fluid and the reactants and the catalyst. Many hydrocarbon conversion processes will be more advantageously performed by maintaining a different temperature profile than that produced by the heat of reaction. In many reactions, the most advantageous temperature profile will be obtained by maintaining conditions that are substantially isothermal. In some cases, a temperature profile exhibiting the opposite of the temperature change associated with the heat of reaction will provide the most favorable conditions. For this reason, methods of contacting reactants and heat exchange media in a crossflow, cocurrent or countercurrent arrangement are generally known. Specific arrangements for heat transfer and reactant channels that more fully control the temperature are disclosed in US-A-5,525,311; The contents of which are incorporated herein by reference. Other useful plate arrangements for indirect heat transfer are disclosed in US-A-5,130,106 and US-A-5,405,586.

Separating the reactants from the coolant or heating fluid present at the inlet and outlet of the plate exchanger arrangement makes the design difficult and complicates the manufacturing process. In many of these designs, the size of the reactor is increased as manifolds and / or wiring are required for communication with adjacent channels. Simplified fluid transfer between adjacent channels also allows for simple distribution of fluid at the inlet and outlet of the plate changer. Improved arrangements for injecting reactants at intermediate positions along the fluid path of the channel may also improve the performance of the reactor.

Channel reactor arrangements often contain particulate catalysts. If the catalyst is deactivated, the catalyst must be replaced. The complex manifold arrangement for dispensing and collecting heat exchange fluids and reactants can be cumbersome for catalyst exchange and time consuming to apply.

Summary of the Invention

The present invention provides perforations in the plates that define channels for indirect heat exchange between the fluids in the plate reactor arrangement. The perforations extend only to a portion of the plate defining the channel, allowing communication of fluid between adjacent channels while maintaining a substantial channel length through which the reactants or heat exchange fluid can pass through the reactor. Some perforations located at one end of the perforated plate may form any number of channel passageways by a single fluid stream through the plate channel reactor. Pressure drop and heat exchange conditions substantially limit the number of passages that any one fluid can make through the channel reactor arrangement of the present invention.

Suitable channel arrangements will exchange heat directly across a common heat exchange surface. This arrangement can use separate heat exchange streams to heat and cool the reaction channels, or use heat exchange fluids or reactants from one channel as reactants or heat exchange fluids in adjacent channels. In particular, feeds or reaction streams derived from reaction channels can provide fuel for combustion and in situ heat generation in adjacent channels. Of course, the heat exchange channel can also be used as a combustion channel to receive fuel for combustion in a form separate from the fluid in the reaction channel.

Useful arrangements may also use different portions of the common channel to perform different functions. These functions include passing intermediate fluid through adjacent channels to transfer heat away from the reaction channel at one location and transfer heat to the heated channel at the downflow channel location. In another arrangement, the intermediate channel and the reaction channel can be arranged in parallel arrangement between the heated channels to adjust the temperature in the reaction channel through the heated channel.

According to various embodiments, the present invention is a reaction apparatus for contacting a reactant with a catalyst in the reaction zone while indirectly heating or cooling the reactant in the reaction zone by indirectly exchanging heat with the heat exchange fluid. The apparatus includes a plurality of spaced plates defining a first plurality of channels having a fluid inlet at one end and a second plurality of channels having a fluid outlet at one end. One or more perforations communicate fluid between the first and second plurality of channels. At least some of the spaced plates form perforations at one end thereof, with each perforation extending only to a portion of the plate defining the perforations.

In particular, in a variant of the invention, loading the catalyst in the reaction channel and adding a catalyst for supplemental exothermic or endothermic reactions can satisfy the purpose of different processes. For example, short loading of the catalyst in the reaction channel may provide space above or below the reaction zone for further feed preheating or exhaust cooling. In addition, extending the heating channel may provide additional surface area for open channel heat exchange for emissions or inlet reactants in the exhaust reaction zone.

In the catalyst, the present invention has particular advantages. Simplifying or eliminating manifolds for heat exchange and for the distribution or collection of reactants frees up space for catalyst loading. Typically the device will use a dispensing manifold on top of the reaction device that dispenses and collects fluid from the fluid inlet and outlet at the top of the channel. Placing the manifold on top allows the channel to define the particle outlet at the bottom of it and integrate the catalyst loading device. Therefore, the channel lower region does not have to have a manifold for removing the catalyst. Since there is no need to provide a screen or other permeable surface underneath the channel, a simple catalyst holding device can control the retention of catalyst in the channel. The device will close the particle outlet when in the catalyst holding position and open the particle outlet in the unloading position. Thus, when a door or other suitable diaphragm is removed from the bottom of the channel, the channels may be left fully open for catalyst removal. In addition, this arrangement can be simplified, allowing fluid to flow continuously through the channel while removing the stream and replacing the catalyst particles.

The perforated plate section in fluid flow will generally indicate the direction of fluid flow. Adjacent channels connected by perforated plate sections will always relatively reflux the interchannel fluid. Nevertheless, a cocurrent arrangement can also be formed by separating heat exchange fluids and reactants.

The plate defining the channel to contain the reactants and the heat exchange gas may take any form that forms a narrow channel. A preferred form of heat exchange member is a corrugated relatively flat plate as defined herein. The corrugations are used to maintain the space between the plates, and also support the plates to provide a system in which narrow channels are well supported. Additional descriptions of such plate system arrangements are described in US Pat. No. 5,525,311.

The present invention is useful for heat generating reactions or heat absorption reactions. One method that can advantageously utilize the inventive arrangements is to produce ethylene oxide. An application of a particularly advantageous method for the present invention is the oxidation of orthoxylene to produce phthalic anhydride (PA). The reactor supplies an orthoxylene feed to a distribution manifold that injects a controlled amount of oxygen in a mixture with orthoxylene. Injecting an oxidizing compound into the manifold prevents the presence of orthoxylene and oxygen in explosive proportions. The plate arrangement of the heat exchange reactor quickly dissipates the high heat of the reaction associated with the synthesis of PA. Enhanced temperature control can increase throughput while improving product selectivity.

It is a further object of the present invention to simplify the supply and recovery of reactants and heat exchange fluids derived from heat exchange reactors using channel arrangements to further compact the channel reactor arrangements, and to simplify the integration of manifolds and fluid channels. .

It is another object of the present invention to transfer reactants or heat exchange fluid through a plurality of passages through a channel reactor arrangement in which the number of manifolds is reduced.

Figure 1 schematically shows the reactor arrangement of the present invention.

2 is a cross-sectional view taken along the line 2-2 of FIG.

3 is a cross-sectional view of the perforated plate of the present invention.

Figure 4 shows a three-dimensional cross-sectional view of the corrugated plate used in the present invention.

5 shows a single corrugated sheet comprising perforations.                 

Figure 6 is a schematic cross sectional view of a reactor arranged in accordance with the present invention.

7 is a cross-sectional view taken along the line 7-7 of FIG.

8 is a cross sectional view showing a schematic arrangement of another embodiment of the reactor of the present invention.

9 is a cross-sectional view taken along line 9-9 of FIG. 8.

10 and 11 are graphs showing temperature profiles and conversion parameters according to the path length of the tubes in the tubular arrangement for oxidizing orthoxylene to produce PA.

12-17 are graphs showing temperature profiles and conversion parameters along the path length of channels in a plate heat exchange reactor arrangement for oxidizing orthoxylene to produce PA.

Detailed description of the invention

The present invention will be useful in any endothermic or exothermic method wherein the reactant or portion of the reactant provides a heat source for heating the endothermic reaction in the arrangement of the plate exchanger member or a heat sink for cooling the exothermic reaction. Can be. Additional conditions for meeting any method using a plate-type exchanger arrangement are typically a relatively small temperature difference (ΔT) and a pressure difference (ΔP) between any heat exchange zone and reaction zone. It is preferable to this invention that a temperature difference is 200 degrees C or less. The pressure difference will remain small and will typically reflect the pressure drop conditions through the catalyst bed. Typically the difference in pressure across the plate member will not exceed 0.5 MPa.                 

At least the reaction channel will generally contain a catalyst to catalyze the reaction. Suitable catalysts for the aforementioned and other methods are well known to those skilled in the art. The reaction channel may be charged with the particulate catalyst as needed during the reaction time for any pre-reaction heating or post-reaction cooling in the reaction channel. Instead of particulate catalysts, it is also possible to coat the catalysts on plate surfaces of various reforming zones. It may be particularly advantageous to coat the reaction catalyst on the plate to provide an upper catalyst portion and a lower catalyyst-free portion that maintains the heat exchange relationship through the channel confinement plate with the secondary catalyst zone.

The heat exchange fluid used in the method or apparatus of the present invention may be any type of fluid capable of providing the necessary cooling or heating capability. Various types of heat exchange fluids can satisfy heating or cooling conditions. Such fluids will include integrated process streams and auxiliary fluids. The fluid may absorb or release heat by detectable means, latent means or reactive means. In highly exothermic processes, molten salts or metals may be particularly useful as heat exchange media.

If suitable to meet the conditions concerning the heat of a particular reaction, those skilled in the art will know about the particular catalyst which preferentially promotes exothermic and endothermic reactions. These catalysts are advantageous for cooling the heat due to reactive cooling and sensing heat or latent heat of the reactants by staying in the heat exchange channel. Examples of using such endothermic and exothermic catalysts are autothermal reforming of light hydrocarbons, usually methane, which provides a gas commonly referred to as "synthetic gas" or "syn-gas". Synthetic gas consists essentially of hydrogen and carbon monoxide, small amounts of carbon dioxide, unconverted hydrocarbons, and other components that may include nitrogen and other inert components. Highly endothermic reforming reactions are effectively balanced with highly exothermic oxidation reactions that can be carried out by partial catalytic or high temperature oxidation of hydrocarbons. Changing the number of moles of hydrocarbons in the reforming or oxidation reactions can balance the heat released and the heat absorbed.

This arrangement is particularly suitable for interconnecting only two pairs of adjacent channels and for integrating a plurality of passage channel arrangements which place an exothermic reaction channel between alternating heating and endothermic reaction channels. When indirect heat exchange with the reaction channel provides heating and cooling, respectively, in the form of providing a three-channel arrangement, relatively cool reactants enter the heating channel. When the reacted stream enters the endothermic reaction channel from the exothermic reaction channel, the reaction channel is further cooled across the shared plate defining the endothermic reaction channel and the adjacent exothermic reaction channel.

1 and 2 show the basic reactor arrangement of the present invention. In this arrangement, the reactor 11 comprises a single group of channel pairs 12. The non-perforated plate 19 separates pairs of heat exchange channels into downflow channel 15 and upflow channel 18. The manifold 13 carries the introduced fluid to the inlet 14 of the downflow channel 15. A perforation 16 formed in the bottom of the perforated plate 17 carries fluid to the upflow channel 18.

Manifold 13 includes an inlet chamber 20 and an outlet chamber 21, as shown in FIG. 2. The partition plate 22 isolates the space of the inflow chamber 20 and the outflow chamber 21. As indicated by the symbol 도입, the fluid introduced flows from line 23 along the inlet chamber 20 to the channel 15 towards the lower inlet 14. The blankoff section 24 of the upflow channel 18 prevents the fluid carried by the inlet chamber 20 from entering the upflow channel 18. Similarly, the outlet chamber 21 collects fluid from the upflow channel 18 as indicated by the symbol ⊙ for removal to the outlet stream 25, where the blank off section 26 provides a fluid channel 15. ) To prevent overflow from the outflow chamber 21.

Channels 15 and 18 may perform a number of different functions. Channel 15 may be cooled by preheating the reactants for the endothermic reaction occurring in channel 18. In contrast, channel 15 may receive a heated reactant stream that further provides heat for the endothermic reaction that occurs in channel 18. Alternatively, channel 15 may contain an oxidation catalyst for combustion heating the reactants introduced into channel 18.

The channels of the invention are particularly suitable for use with particulate catalysts. 1 shows one catalyst loading arrangement for exothermic reactions. The cold introduction reactant is introduced through line 23 and passes down channel 15. As the introduced reactant passes over the top of the channel 15, the top of the channel 18 serves as a heat exchange zone to preheat the feed inlet to the exhaust reactant. The exhaust reactant was heated by the exothermic reaction occurring at the bottom of channel 18. As the reactant passes through the bottom of the channel 15, the channel is further heated inversely proportional to the exothermic reaction occurring at the bottom of the channel 18. As the heated reactant passes through the perforations 16 at the bottom of the perforated plate 17, the reactants pass through the catalyst particles 27 which partially fill the bottom of the channel 18. The perforations 16 in the diaphragm are sized to prevent the passage of catalyst particles from channel 18 to channel 15 while allowing reactant fluid to pass from channel 15 to channel 18.

The arrangement of FIG. 1 is particularly suitable for replacing the catalyst in channels 15 and / or 18. In the particular arrangement shown in FIG. 1, the catalyst 27 is only present in the channel 18 used for the exothermic reaction. If catalyst 27 is deactivated or needs to be replaced, it may be possible to unload the catalyst from channel 18 with a catalyst loading device, generally as shown at 28. At least, the unloading device has at least one set of doors 29 which prevents catalyst from escaping from the channel by blocking at least the bottom 30 of the channel 18 when the door 29 is in the closed position as shown by the gothic line. It can be configured as. Moving the door 29 to the open position, as shown by the dashed line, opens the bottom 30 of the channel 18 to discharge catalyst particles.

The loading device 28 may further introduce a second set of doors for selectively holding and unloading catalyst from the channel 15. A second set of doors 31 is shown in the catalyst loading open position. The second door 31 comprises a slot 32 which separates the sealing fingers 33. When the door 31 rotates upward to the bottom 34 of the channel 15, the sealing projection 33 blocks the bottom 34 of the channel 15 so that no catalyst is released. The slot 32 has a second door 31 for the catalyst in the channel 18 to fully unload before the door 31 is moved to the open position to unload the catalyst from the channel 15, as shown in FIG. Let it flow around. Once the catalyst is removed from the channel 18, the door 31 is opened to allow the catalyst to flow out of the channel 18 without intermixing with other catalyst particles.

It is easy to load the catalyst into the channel 18 and optionally the channel 15 from the top of the reactor 11. To load the catalyst, the manifold 13 can be removed from the top of the channel to expose the channel opening, the inlet chamber and the outlet chamber (20 and 21, respectively). If the catalyst is to be used only in the channel 18, a fixed screen can block the inlet 14 of the channel 15 to prevent particles from flowing therein. If catalyst loading occurs in both channels, an appropriate slotted plate may be introduced and placed on top of the channels 15 and 18 to selectively block the channels so that they do not receive catalyst during certain cycles of the loading operation.

The catalyst may be moved while the reactant or heat exchange fluid is circulating through the reactor 11. The inlet and outlet chambers 20 and 21 can provide a distribution space in which the catalyst on top of the channel that is open in each particular chamber can be dispersed. In such an arrangement, the chamber or series of chambers may provide a loading device in the form of a collection chamber for receiving particulate matter on behalf of the doors 29 and 31. Suitable collection chambers may have an arrangement similar to that shown in FIG. 2 to collect catalyst from selected channels. Adjusting the discharge and addition of catalyst from the top and bottom of reactor 11 can provide any desired catalyst level in the reactor.

The present invention relies on relatively narrow channels for efficiently exchanging heat through thin plates. In general, the channel width should average less than 1 inch, preferably average width less than ½ inch. Suitable plates of the present invention include any plate having a high heat transfer rate. Thin plates are preferred, and the thickness is generally 1-2 mm. Typically the plate consists of an iron or nonferrous alloy such as stainless steel. Preferred alloys for use in plates are extreme temperatures and contain high proportions of nickel and chromium. The plates can be formed into curves or other shapes, but generally flat plates are preferred for lamination. Flat plates may include channels formed by machining, chemical etching or other methods. In addition, each plate is smooth and additional members such as spacers or perforated tabs can cause fluid turbulence in the channel.

Each plate is preferably corrugated to produce a flow of reactant and heat exchange fluid. The corrugations maintain various channel widths defined by their height. In the case of corrugations, it is most practical to set the average channel width as the volume of the channel per cross-sectional area parallel to the major surface of the plate. According to this definition, a corrugated plate having a wall of nearly straight slopes will have an average width of ½ of the maximum width of the channel.

3 shows a preferred corrugated arrangement for the plate 17 separating the channels 15 and 18. The corrugated pattern can serve two or more functions. One function is to structurally support adjacent plates. Another function is to promote turbulence, which increases the heat exchange efficiency of the narrow reaction channel. 3 shows the corrugations formed by the ridges 37 and valleys 38. The frequency or pitch of the folds can be varied as needed to vary the turbulence. Thus, shallower corrugations with respect to the fluid flow direction as shown by floor 37 and valleys 38 cause less turbulence, while fluid flow direction as shown by floor 39 and valleys 40. Increasing the crease slope with respect to can increase turbulence where necessary. By varying the slope and frequency of the corrugations in a single heat exchange channel, heat transfer factors can be varied in different parts of the channel. The channel preferably includes a flat portion 41 around it to facilitate channel closure of the top, bottom, left and right as needed. Except for the perforations, the plate 19 is preferably substantially the same as the plate 17 and includes pleats, varying inclination of the pleats, as needed, for turbulent flow and flow factors for heat exchange and other purposes. Can change.

The perforations 16 extend over the plate 17. Usually the perforations 42 are relatively small in diameter such that fluid flows through the perforations and the catalyst cannot move through the perforations. Perforations vary in size from about 1.5 mm to about 10 mm. Perforations 16 may be located in the middle of the plate to provide fluid bypass in certain processing applications, but are usually located at one end of the plate. Placing the corrugation at one end of the plate maximizes the fluid flow path through the channel. The flow area provided by the perforations is generally equal to or greater than the net flow area through which the fluid flows along the channel flow path. If one of the channels comprises particulate catalyst material, the net flow area consists of the average open area between the catalyst particles through the transverse portion of the channel 18. In most cases the porosity is less than ½ of the channel length, typically less than 25%. Preferably, the perforations of the channels extend up to 10% or less of the channel length to maximize the fluid flow path along the channel.

4 shows a typical cross-sectional view of a corrugated plate arrangement in which the corrugations of plate 44 extend in opposite directions to the corrugations of plate 46 to form alternating channels 47 and 48. Holes 49 provide a perforation of the invention in plate 44. 4 illustrates a preferred arrangement of the corrugated plate, where on the opposite side of the corrugated plate the herring thorn pattern extends in the opposite direction and the sides of the opposing plate contact each other to form a flow channel and establish a structural support for the plate section. to provide. 5 further illustrates another possible plate structure.

Alternately placing each reaction channel with a heat exchange channel is not essential to the practice of the present invention. The possible shape of the reaction section can reduce the pressure drop on the heat exchange medium side by placing two or more heat exchange channels between each reaction channel. The dual channel arrangement can be formed from a perforated plate that separates adjacent heat exchange channels and includes perforations in the front. Using packed or perforated plates can increase heat transfer with the reaction channel while improving circulation across the entire cross section of the heated channel.

6 and 7 illustrate an arrangement in which two independent groups of channel pairs circulate different fluids in a form separated from opposite ends of the reactor arrangement 50. Inlet stream 51 supplies fluid to manifold array 52 including upper inlet chamber 53 and upper outlet chamber 54. The inlet chamber 53 distributes the upper inlet stream 51 into channel pairs 55, as shown by the letter VII. The upper outlet stream 56 collects fluid from the first plurality of channels 55 through the upper outlet chamber 54 at the channel opening indicated by symbol ⊙. The perforations 57 connect two channels in the first plurality of channels 55. Similarly, lower inlet stream 58 is distributed to second plurality of channels 59 via manifold arrangement 60. In the second plurality of channels 59, the upper perforations 61 are in communication with the channel for withdrawing the lower outflow stream 62 through the manifold 60.

This arrangement allows two different fluids to be circulated in a full cross flow relationship in the heat exchange reaction using a simple manifold arrangement at opposite ends of the reactor arrangement. In this way, the first plurality of channels may form a heat exchange channel for circulating the heat exchange fluid and the second plurality of channels may form a reaction channel for receiving the reactant stream and for transporting the reacted stream.

8 and 9 illustrate an arrangement of reaction channels using an odd number of passages to provide a simplified inlet and outlet manifold arrangement. In FIG. 8, inlet stream 65 enters inlet manifold 66 with a single chamber. The inlet manifold 66 into which the fluid enters flows downward into the inlet channel 68 of the series of three passage channel arrays 67. Perforation 78 at the bottom of plate 69 passes fluid from inlet channel 68 to intermediate channel 70 and upper perforation 74 passes fluid from intermediate channel 70 to outlet channel ( Continue to 71). The manifold 72, which also includes a single open chamber, recovers the effluent from the outlet channel 71 for exit to the outlet stream 73. In this manner, the arrangement of FIG. 8 alternately places perforations at the end of the plate to form a channel that delivers fluid at one end of the channel and defines a flow path for collecting fluid from the opposite end of the channel.

FIG. 9 is a further variation of the arrangement of FIG. 8, where the side manifold 75 extends between multiple banks 76 of heat exchange channels. The manifold arrangement shown in FIGS. 6-8 can transfer a single fluid or multiple fluids to a heat transfer channel. The side channel 75 may dispense or withdraw liquid from the side 77 of one or more channels created by the spaced plates. 8 and 9 show the openings 79 on the side of the channel 70 for transporting the intermediate stream 80. The opening 79 may extend through the entire length of the channel in communication with the side manifold or a portion thereof by the hole 79 'as shown in FIG. From a practical configuration point of view, it may be more convenient to provide an opening at the side of the channel with intermittent welding at the side of the channel rather than forming an open hole.

The following examples show the operation of a channel reactor arrangement of the type using a tubular reactor base case and two independent flow paths as shown in FIGS. 6 and 7. All examples show the oxidation of orthoxylene with phthalic anhydride. Numerical data uses established reaction rate data and experimentally generated heat transfer data. All catalyst data are based on performance parameters for vanadium pentoxide surface coated with a silicon carbide base material with a surface area of 2000 cm ² / g. All examples are engineered to keep the phthalide content in the effluent less than 1000 ppm in the PA product. The examples used molten salt as the refrigerant.

Example 1

This example confirmed the performance of the tubular reactor base case and yielded results similar to the current industrial tubular reactor performance. In this basic case, an air feedstock containing otroxylene at a concentration of 75 g / Nm ³ feeds was passed through a 25 mm diameter 3 mm long tube at a mass flux rate of 10,000 kg / m ² / hr. A pressure drop of 0.3 bar was calculated along the pipe. The tubular reactor model utilizes annular particles with an outer diameter of 9 mm and perforations, usually 5 mm in diameter. Cool by circulating the salt bath at a temperature of 698 ° K around the cell surface of the tube. The feed enters the tubular reactor at a temperature of about 700 ° K. The final phthalide content in the PA product was 1000 ppm or less. 10 graphically illustrates a temperature profile along a length of a representative tube. The tube exhibits a peak temperature of about 835 ° K within the first 50 cm of the path length. FIG. 11 illustrates that the conversion of orthoxylene is nearly complete at approximately the first 100 cm of tube length. Also shown in FIG. 11, continued conversion in vitro lowers the concentrations of orthotolualdehyde and phthalide to 1000 ppm level while increasing PA selectivity to about 83%.

Example 2

The reactor of plate heat exchanger type is operated with the same orthoxylene inlet concentration and mass flux through the heat exchange channel as in the tubular reactor. The channel arrangement comprises a 2 mm spherical catalyst in one channel of the pair of channels 6 mm apart. In order to maintain the pressure drop through the channel at 0.3 bar equal to the tubular reactor, the treatment flux in the plate reactor arrangement is lowered to 7500 kg / m ² / hr. Nevertheless, the sizing of the plate exchange reactor keeps the ratio of heat transfer surface area to catalyst surface area based on the reactor volume the same as in the tubular reactor arrangement. When the orthoxylene concentration in the air feed is equal to 75 g / Nm ³ , in order to maintain the same phthalide level in the PA product, the process of inlet temperature is increased by 15 ° C. or about 713 ° K in the tubular reactor case Increase to the temperature of Even with increasing inlet temperature, the peak temperature in the channel is reduced to about 815 ° C. as shown in FIG. 12, indicating a temperature drop of about 20 ° C. compared to the tubular reactor case. 13 also shows that the conversion of orthoxylene occurs rapidly along the path length of the plate exchange reactor, with the selectivity to PA being approximately the same and the concentrations of orthotolualdehyde and phthalide less than 1000 ppm. Thus, the temperature reduction of this example demonstrates that the plate heat exchange reactor has about 30% greater total heat transfer capacity than the tubular reactor.

Example 3

Example 3 shows the concentration of orthoxylene in air for the plate exchange reactor over the range of 75 g / Nm ^{3 to} 110 g / Nm ³ to determine the concentration at which the same peak temperature as the tubular reactor is calculated in the plate heat exchange reactor. Evaluate the increase. Since heat is generated from further orthoxylene oxidation, the circulating salt temperature of 713 ° K in Example 2 should be increased to about 717 ° K in order to maintain the phthalide concentration in the PA product below 1000 ppm. At a concentration level of about 105 g / Nm ³ , the peak temperature of the plate reactor (see FIG. 14) is close to the maximum temperature of the tubular reactor arrangement. As demonstrated in FIG. 15, using a plate exchanger while maintaining PA selectivity at about 83 mole percent can significantly increase the maximum orthoxylene concentration over the tubular reactor case.

Example 4

Example 4 demonstrates the effect of stepwise injection of orthoxylene on the temperature and conversion rate at the midpoint of the channel to redefine the maximum concentration of 75 g / Nm ³ . Stepwise injection of the feed in this example uses the side distribution channels of FIGS. 8 and 9 in parallel with one of the group of channel pairs shown in FIGS. 6 and 7. This example reduces the initial feed injection to lower the treatment flux at the inlet of the plate reactor to 5525 kg / m ² / hr for the first stage of orthoxylene injection. In this arrangement, additional orthoxylene is injected in the middle of one of the channels of each pair of upstream and downstream channel groups at a position of 30 cm along the path length of the heat exchange reactor. The bottom treatment flux is used to lower the temperature of the circulation salt bath to 700 ° K, which is equal to the tubular reactor inlet temperature. The path length of the channel of this embodiment is increased to 130 cm in total by providing 30 cm for the first step while keeping the same at 100 cm for the second step as used in Examples 2 and 3. . As the length increases, the phthalide content in the PA product is lowered below 1000 ppm. However, even as the length increases, the total pressure drop is less than 0.3 bar, as in the example of a tubular reactor. Figure 16 shows the maximum peak temperature of 810 ° K or less in the first stage. FIG. 16 shows that orthoxylene conversion is nearly complete within the first 30 cm from the injection point. 17 demonstrates that PA selectivity remains above 83%. As a result, a process unit using a tubular reactor producing PA 50 kMta requires 33 m ³ of catalyst. In contrast, a plate heat exchange reactor using multiple feed injections to produce the same amount of PA product requires only about 12.8 m ³ of catalyst, which can significantly reduce the capital cost of the plate reactor arrangement compared to the tubular reactor arrangement. . From another angle, this example shows that the orthoxylene feed concentration using stepwise feed injection is virtually twice that of the tubular reactor.

The entire example demonstrates a number of processing advantages of plate reactor arrangements over tubular reactor arrangements. The comparison of the examples shows that using a plate heat exchange reactor arrangement that introduces a mixture of air and orthoxylene at one inlet point to produce phthalic anhydride increases the overall thermal efficiency. Further advantages can be obtained by using a plate reactor arrangement with increasing concentrations of orthoxylene in air at one feed inlet. In addition, the stepwise feed injection of orthoxylene in the plate reactor configuration substantially lowers the plate reactor reactor cost. These savings reduce air compression costs by 50%, and the plated reactors are relatively small in size compared to tubular reactors, thereby substantially reducing capital costs.

Claims (14)

A reaction apparatus for contacting a reactant with a catalyst in a reaction zone while indirectly heating or cooling the reactant in the reaction zone by indirect heat exchange with a heat exchange fluid, A plurality of laminated plates 17, 19 defining at least one first plurality of channels 15 having a fluid inlet 14 and a second plurality of channels 18 having a fluid outlet; An unperforated plate 19 for blocking fluid flow between adjacent channels and a perforated plate 17 that alternates with the non-perforated plate to define a continuous flow path from the fluid inlet 14 to the fluid outlet A plurality of lamination plates 17 and 19 including; And One or more perforations 16 for communicating fluid between the first and second plurality of channels 15, 18, wherein some or all of the laminated plates form perforations at one of their ends and each perforation ( 16) extends only on a portion of the plate (17) forming the perforation, wherein at least one set of perforations is in a position opposite the fluid inlet (14). The system of claim 1, further comprising a distribution manifold (20, 21) and a catalyst loading device (28), wherein the distribution manifold (20, 21) comprises a first plurality of channels (15) and a second Distributes and withdraws fluid from the fluid inlet 14 and the fluid outlet at the top of the plurality of channels 18, and some or all of the first plurality of channels and the second plurality of channels of the channels exit the particle at the bottom thereof. 30, wherein the fluid inlet 14 of the first set of channels 15 or the fluid outlet of the second set of channels 18, or both receive particles, and the catalyst loading device 28 The apparatus is to block the particle outlet (30) when in the catalyst holding position and open the particle outlet when in the loading position. The method according to claim 1, wherein every other one of the plurality of laminated plates (17) forms perforations (16) at its bottom to form bottoms of the first and second plurality of channels (15,18). The device is in direct communication for fluid flow, the fluid inlet (14) and the fluid outlet at the same end as the first and second plurality of channels (15,18). 3. The first and second plurality of channels (15, 18) form a particle outlet (30) at the bottom thereof, and the unloading device (28) is provided for the particle loading while in the first position. A first door 29 which retains particles in the channel when opening one of the channels of and in the second position, the loading device comprising a first door when the second door 31 retains particles in the plurality of channels; And a second door (31) positioned above the door and having a slotted plate shape. 2. The perforations 61, 57 on the perforated plate alternately exist from one end to the other end of the channel, the first plurality of channels 55 and the second plurality of channels 59 and Recovering and dispensing fluid from the first manifold 52 and the second plurality of channels at one end of the channel for recovering and dispensing fluid from the first plurality of channels of the first and second plurality of channels 55, 59. To form an independent flow path through the second manifold (60) at opposite ends of the channel. A reaction apparatus for contacting a reactant with a catalyst in a reaction zone while indirectly heating or cooling the reactant in the reaction zone by indirect heat exchange with a heat exchange fluid, A plurality of lamination plates 69 defining a first plurality of channels 68, 70, 71 having a fluid inlet at one end and a second plurality of channels 68, 70, 71 having a fluid outlet; A plurality of laminated plates 69 comprising non-perforated plates to block fluid flow between adjacent channels and two or more perforated plates 69 alternately deployed between each non-perforated plate; Some or all of the laminated plate 69 forms a perforation at one of its ends and each perforation 74, 78 extends only over a portion of the laminated plate 69 forming the perforation, and at least one set of perforations One or more perforations 74,78 for communicating fluid between the first plurality of channels 68, 70, 71 and the second plurality of channels 68, 70, 71, which are opposite the fluid inlet. ); Adjacent perforated plates having perforations 74, 78 at opposite ends to form continuous flow passages that traverse from fluid inlet to fluid outlet in at least three channels 68, 70, 71; And And a first manifold (66) for dispensing fluid at the fluid inlet at one end of the channel and a second manifold (72) for withdrawing fluid from the opposite end of the channel. The method of claim 1, wherein the first plurality of channels 55 define a heat exchange channel for circulating the heat exchange fluid, and the second plurality of channels 59 receive the reactant stream and deliver the reacted stream. Defining a reaction channel for the device. A reaction apparatus for contacting a reactant with a catalyst in a reaction zone while indirectly heating or cooling the reactant in the reaction zone by indirect heat exchange with a heat exchange fluid, A plurality of spaced apart defining a first plurality of channels 68, 70, 71 having a fluid inlet at one end and a second plurality of channels 68, 70, 71 having a fluid outlet at one end Plate 69; One or more perforations 74, 78 for communicating fluid between the first and second plurality of channels, wherein some or all of the spaced apart plates form perforations at one end of each end and each perforation is perforated. Extends only to a portion of the forming plate; And A portion of the channel that defines a side manifold 75 extending across the side of the channel and an opening 79 in communication with the side manifold for dispensing or withdrawing fluid from the side manifold. And a side. 8. The length L of the perforations 16 according to claim 1, wherein the sum of the open areas defined by the perforations 16 is greater than or equal to the net flow area of the channel. 9. Silver plate (17) extending to 0 <L ≦ 25% of the length. 8. The device of claim 1, wherein the reaction channel has an average width d of 0 <d ≦ 2.5 cm (1 inch). 9. 8. The apparatus of claim 1, wherein the plate is flat and the channels are etched into the plate. 9. The method according to claim 6 or 8, wherein the sum of the open areas defined by the perforations 74 and 78 is equal to or greater than the net flow area of the channel and the length L of the perforations 74 and 78 is the plate 69. Extending to 0 <L ≦ 25% of length. The device of claim 6, wherein the reaction channel has an average width d of 0 <d ≦ 2.5 cm (1 inch). The device of claim 6, wherein the plate is flat and the channel is etched into the plate.

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