RU2776384C2 - Radial flow reactor - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: group of inventions relates to a device suitable for use as a distributor or collector in a reaction tank, a tank with a radial flow, a method for processing synthesis gas. The device includes an open end and many rigid columnar parts. Each columnar part includes a cylindrical outer screen formed of parallel, spaced rods, and a perforated inner screen attached to the outer screen. The inner screen is formed from a plurality of adjacent perforated support elements supporting rods spaced apart from each other. Rigid columnar parts additionally include a means for controlling the flow of gaseous process fluid into or out of the device. The device can be used in radial flow tanks used in chemical processes such as methanol synthesis.

EFFECT: group of inventions provides a reduction in fluctuations in the speed of the process fluid.

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Description

The present invention relates to a distribution or collection device suitable for use in a radial flow tank, a radial flow tank including the device, and a method of using the device in a radial flow tank.

Radial flow tanks are well known and typically include a domed cylindrical shell that has a process fluid inlet and process fluid outlet. A centrally located perforated distributor or manifold, which is typically cylindrical, is connected to the inlet or outlet and extends along the longitudinal axis of the reservoir from one end to the other, providing a central cavity into or from which process fluid can flow. There is also an external cavity, which may be continuous or discontinuous, from which or into which process fluid may flow into or out of the outlet. A catalyst layer is usually located between the central and outer cavities. The process fluid supplied to the tank through the inlet may enter the outer cavity, then pass radially inward through the catalyst bed into the central cavity, in which case the central cylinder may be called a manifold, and from the central cavity to the outlet. Alternatively, the process fluid supplied to the tank through the inlet may enter the central cavity, in which case the central cylinder may be called a distributor, then pass radially outward through the catalyst bed into the outer cavity, and then from the outer cavity to the outlet. Such tanks are described, for example, in US 4374094.

The central distributor or manifold in such tanks must be strong enough to support the weight of the catalyst bed and resist expansion and contraction of the bed during operation. A simple design is often used in which a cylinder is made by rolling and welding a metal sheet into which, typically, many thousands of holes are pre-drilled. However, such a construction takes a long time to complete, and a non-perforated part is formed during welding, resulting in non-uniform flow of the process fluid. Because of this, there is a part of the catalyst or sorbent layer with a non-uniform flow. In addition, conventional designs tend to have small openings, such as 2 mm, which can become clogged, which reduces the efficiency of the device.

Known design options for a simple perforated cylinder. For example, US Pat. No. 4,421,723 and US Pat. No. 4,452,761 describe a fixed bed radial flow reactor having a perforated central tube surrounded in turn by a screen. US 4,374,094 describes a design in which there is a tapered screen around a central cylindrical manifold, or the manifold itself is tapered. In the latter case, the collector includes a single screen of wedge-shaped vertical rods spaced apart from each other, welded to the rings. These designs have the same disadvantages as those that arise when using a perforated cylinder.

In addition, within the distributor, pressure increases as the process fluid velocity decreases from highest axial velocity at the open end or ends to zero axial velocity at either the closed end or an intermediate point in a dual open end design. There is a similar reduction in pressure within the manifold when the fluid is slowly accelerated from zero axial velocity to maximum axial velocity at the open end or ends. These phenomena are described by the Bernoulli equation, well known in the field of hydrodynamics. When the process fluid is a gas, the static head component is small, and for both the distributor and manifold, the lowest pressure occurs at the open end or ends where velocity is highest. These pressure differences create differences in process fluid velocity and hence flow along the length of the distributor or manifold, which is undesirable.

The Applicant has found a screen design that provides greater design flexibility compared to prior art designs and solves the problem of fluctuations in the speed of the process fluid.

The authors have made a device in which the problems of previous designs are overcome.

The invention thus provides an apparatus suitable for use as a distributor or manifold in a radial flow reaction vessel, comprising an open end and a plurality of rigid columnar portions, each columnar portion comprising a cylindrical outer screen formed from parallel, spaced apart bars. , and a perforated inner screen attached to the outer screen, wherein said inner screen is formed from a plurality of adjacent perforated support members supporting spaced apart rods, wherein the rigid columnar portions further include means for controlling the flow of gaseous process fluid into the device or from the device.

In addition, the invention provides a radial flow tank including this device and a method of using the device in a radial flow tank.

While the device can be used in radial flow tanks comprising a fixed bed of particulate catalyst, it can also be used in radial flow tanks comprising a fixed bed of particulate sorbent. By the term "sorbent" the authors understand the adsorbent and absorbent.

The device includes a plurality of rigid columnar parts. The diameter of these parts, preferably the same. Preferably, the diameter lies in the range of 0.45-0.65 m, since with this size the operator can penetrate inside during loading of the catalyst. The length of the parts may be in the range of 1-3 m, preferably 1.5-2.0 m. The parts may have the same length or different lengths. In a preferred embodiment, the length of adjacent parts decreases from one end of the device to the other. This reduces the risk of installing parts in the wrong order.

During operation, process fluid may be supplied to one end of the device, in which case the device has an open end and a closed end opposite the open end. Alternatively, process fluid may be supplied to both ends of the device, in which case the device has two open ends opposite each other. In particular, the device is suitable for operation in a radial flow tank having a single process fluid inlet, and therefore, preferably, the device has an open end and a closed end opposite the open end.

Cylindrical outer screen is formed from parallel bars spaced from each other. The outer screen has holes between the rods that are sized to allow passage of process fluid but prevent catalyst or sorbent particles from entering the device. The maximum width of the holes in the outer screen, in practical terms, can be in the range of 0.5–10 mm, depending on the particle size of the catalyst or sorbent. A maximum distance in the range of 0.5–2.5 mm is particularly advantageous. Preferably, the outer shield is made of a suitable durable material such as steel, including stainless steel.

The rods may be annular and may be placed perpendicular to the longitudinal axis of the cylinder. Alternatively, the bars may be linear and parallel to the longitudinal axis of the cylinder. Alternatively, the bars may be helically wound around the longitudinal axis of the cylinder.

The bars rest on perforated support elements. The angle between the rods and the supporting elements can be from 60 to 120 degrees, preferably 80 to 100 degrees, especially around 90 degrees, since the device has a high strength. Thus, the support elements are preferably arranged perpendicular to the parallel spaced bars. If the bars are arranged perpendicular to the longitudinal axis of the cylinder, the perforated support elements are preferably arranged parallel to the longitudinal axis of the cylinder. If the bars are arranged parallel to the longitudinal axis of the cylinder, the perforated support elements are preferably arranged perpendicular to the longitudinal axis of the cylinder. In such an arrangement, when in place, the bars forming the outer screen of the apparatus in this embodiment are generally vertical. This has the advantage that the catalyst or sorbent in contact with the rods is less likely to be damaged by contact as the bed expands and contracts. If the bars are helically wound around the longitudinal axis of the cylinder, the perforated support elements are preferably at an angle of 0-90 degrees to the longitudinal axis of the cylinder, i.e. parallel or perpendicular to the longitudinal axis, or at an intermediate angle, properly supporting the bars.

The cross section of the bars can be round, square, rectangular, triangular or polygonal. Preferably, the rods have a triangular or wedge-shaped cross section. A particularly effective outer screen is formed from V-shaped bars. Such materials are mass-produced, for example, under the Vee-Wire ^RTM brand by Johnson Screens. The triangular or wedge-shaped rods or rods are desirably positioned with the apex of the triangle or wedge facing inward toward the center of the device. This prevents the sorbent or catalyst particles from getting stuck in the outer screen, which would be undesirable. The maximum width of the rods or rods can be in the range of 1-5 mm.

The outer screen is attached to the inner screen, preferably by welding.

The inner screen is formed from a plurality of adjacent perforated support elements, on which bars spaced apart from each other are supported. Preferably, the inner shield is made of a suitable durable material such as steel, including stainless steel. The support members are adjacent but may be spaced apart, although this is less preferred as the strength of the device may be reduced. In addition, if there is a distance, it is preferably such that the process medium can pass between the elements, but not particles of catalyst or sorbent, which may have penetrated through the outer screen. In a particularly preferred embodiment, the support elements are attached to each other, which provides increased strength of the device. Attachment may be by welding or other suitable attachment method.

The support members are desirably open to form channels through which process fluid can flow in or out of the outer screen. The Applicant has found that the use of open support members to form the inner shield provides much greater flexibility in device design compared to prior art designs. Unlike solid rods, such support elements provide improved process fluid flow in the device and reduce weight. The channels may be formed by each support member having two spaced apart attachment points and a curved or polygonal portion connecting the attachment points and extending into the interior of the device. The channels may be appropriately formed by a support member with a cross section selected from semi-circular, L-shaped, including first and second flanges, or C-shaped, including first and second flanges separated by a flange, each flange optionally having a ledge. . L-shaped flanges can be angled from 45 to 135 degrees. C-Flanges can be at right angles to the flange, or the angle can be between 90 and 135 degrees. The length of the shelf can be in the range of 10–150 mm. The length of the flanges can be in the range of 10–100 mm. The protrusions, if present, may have a length in the range of 1-10 mm. The thickness of the flange, flanges and projections can be in the range of 1–5 mm. Designs in which the support elements are made of perforated C-sections are particularly preferred. C-sections, also referred to as C-channels, track or rack sections, are commercially available. The maximum channel width can be in the range of 10-150 mm, preferably 10-100 mm. Thus, for a support element with a semi-circular cross section, the diameter can be in the range of 10-150 mm, preferably 10-100 mm. Similarly, for a C-section support member with flanges at 90 degrees to the flange, the width between flanges or lugs may be 10-150mm, preferably 10-100mm. By using such structures as support members, weight is reduced compared to prior art solid rings while providing the same high strength device as prior designs.

The support elements are provided with multiple perforations, thereby forming an internal perforated screen. The holes are preferably on the opposite side of the inner screen, ie on the side of the inner screen facing the outer screen. The holes may be round holes or other shaped holes such as square or rectangular. Holes can be punched instead of drilled, which speeds up the production process. The maximum width of the holes, eg diameter, may be in the range of 2-10 mm, preferably 3-7 mm. Larger openings in the inner screen are possible because the outer screen is the first barrier to the catalyst or sorbent. Larger holes are less likely to clog and are easier to clean. In addition, using larger holes reduces the number of holes that need to be made, so the production process is even faster.

The device has at least one open end through which process fluid can enter or leave the device. The open end may have a diameter less than or equal to that of the outer shield. The device may have two open ends. Alternatively, the device may have an open end and a closed end. The closed end, for example, can be made by attaching a non-perforated plate to the inner and outer screens. The closed end can be made as part of the device, or can be made when installed in a radial flow tank by connecting the outer and inner screens to a proper plate inside the reactor. In a vertical tank, the closed end may be at the top or bottom of the catalyst bed. In one preferred design, the open end is adjacent to the top of the catalyst bed and the closed end is formed at the bottom.

The apparatus of the present invention further includes means for controlling the flow of gaseous process fluid into or out of the apparatus.

In one embodiment, the means for controlling the flow of gaseous process fluid into or out of the device is to provide more and/or larger and/or smaller spacing openings in the inner screen adjacent to the open end. Thus, in the portion adjacent to the open end, the openings in the inner shield may be larger than the openings in the adjacent portion. Additionally or alternatively, in the part adjacent to the open end, the number of holes in the inner screen may be greater than the number of holes in the adjacent part.

Additionally or alternatively, in the part adjacent to the open end, the interval between holes in the inner screen may be less than the interval between holes in the adjacent part.

Conveniently, if the pitch or vertical spacing between the holes is fixed by the proper size of the supporting elements. Thus, the height of the supporting elements can lie in the range of 10–150 mm, while the holes are located along their middle. In addition, the vertical pitch can be easily changed by passing holes in adjacent support elements. Thus, the vertical pitch can be changed to double or even triple the width of the support element. The pitch of the holes or the spacing of the holes around the circumference along the support members can also be easily adjusted. The circumferential pitch can be larger than in conventional designs. The interval between the holes around the circumference can be in the range of 10–150 mm. The vertical and circumferential pitch in this device can be easily changed. Preferably, the holes are arranged in a triangular pattern. When used to improve fluid distribution in the catalyst or sorbent, the total perforation area can be 0.5-5% of the surface area of the inner screen, preferably 2-3%.

It is desirable to set the number of holes per square meter so that the value of (flow through the hole) x (number of holes per m ² ) is constant at all points of the distributor or manifold. It is desirable that the flow/m ² be the same, which means that the number of holes per m ² can be chosen such that (flow through the hole) x (number of holes per m ² ) = const at all points of the distributor.

For a valve, flow through the orifice is proportional to the square root of (P1+P2 - P3), where P1=inlet pressure on the inside of the center valve; P2=pressure recovery in the distributor due to deceleration, according to the Bernoulli equation (P + ½ρv² + ρgh=const); and P3=pressure outside the distributor. P1 and P3 are constant for a particular design, but P2 varies along the length of the valve from 0 to ½ρv². For the case when the holes are located in a regular triangular pattern, the number of holes per m ² will depend on the diameter of the hole and the given flow area. So, for example, for a throughput of 2.5%, the required number of holes is 8018 holes per m ² for holes with a diameter of 2 mm and 1282 holes per m ² for holes with a diameter of 5 mm.

For a typical radial flow methanol steam converter, the square root of (P1+P2 - P3) can vary from about 123 to about 173 (ratio 1.41). This means that the required number of holes per m ² can vary from 8018 to 5670 holes with a diameter of 2 mm (ratio 1/1.41) or from 1282 to 906 holes with a diameter of 5 mm (ratio 1/1.41). However, since changing the hole pitch from one hole to another may be impractical, it is preferable to simply adjust this number for adjacent parts of the device by adjusting the number of holes per m ² for each of them.

If a layer of inert ceramic moldings, such as ceramic balls, is placed between the distributor or manifold and the catalyst or sorbent, the spacing of the holes may be equal to the depth of the inert ceramic layer. Therefore, for a layer 200 mm deep, the spacing of the holes can also be 200 mm, which gives about 30 holes per m ² for holes with a diameter of 5 mm.

The dimensions of the device may be selected according to the flow rate of the process fluid. Thus, the speed at the open end or ends can be between 0.5 and 2 times the speed in the connecting piping, however, from a practical point of view, approximately equal to the speed in the connecting piping. For example, the fluid velocity is 20–40 meters per second.

The device includes many, for example, 2-5 or more, columnar parts. These parts are connected to each other to form a device. The parts can be connected outside the tank in which they are to be installed, or inside the tank. Preferably, the parts are joined within the tank in which they are to be used. The length of the columnar parts may depend on the maximum allowable free fall height of the catalyst or sorbent or the weight of the part. In addition to facilitating fabrication, the use of multiple parts makes it easier to accurately load the catalyst or sorbent around the device in the tank, thereby reducing the potential for breakage and dust generation. The simple design of the present device consists of fewer, longer subassemblies than prior art devices, thereby speeding up its installation. In addition, the length of the assembly units can be different, for example, from a minimum to a maximum, in order to simplify sequential assembly on site.

Column connection options include overlapping push-in connection and flange connection. The collar and groove connection can be made using countersunk bolts to obtain a relatively smooth joint, ie, a connection that does not protrude substantially from the inside or outside surface of the device. A flange connection, on the other hand, protrudes into or out of the device. The flange connection can be oriented with the flanges either inside the device or outside the device. The variant with internal flanges provides a relatively smooth outer surface of the device, however, the authors found that in this case, a pressure drop is created inside the device. The external flanged option, while providing a relatively smooth internal surface of the device, can be difficult to install through manholes commonly found in reaction vessels and potentially introduce voids in the catalyst or sorbent bed under the flanges, which is undesirable.

The authors have found that the combination of an overlapping push-in connection and an internal flange connection provides some advantages during operation of the device compared to using only an internal flange connection. For example, if all connections were internal flanges, then, as the authors found, the pressure drop inside the device could be greater than the pressure drop in the holes, which means that the pressure inside the device after the flange would be lower than the pressure in the catalyst or sorbent bed. near the previous section of the device, causing recirculation of the process fluid, which is highly undesirable.

Therefore, in another design, the means for controlling the flow of gaseous process fluid into or out of the device includes the use of an overlapping plug-in connection to connect parts of the device in the immediate vicinity of the open end and an internal flange connection to connect parts located further from the open end.

For a bottom feed tank equipped with an open end device at the bottom and a closed end device at the top, this means that an overlapping push-in connection is used at the bottom of the device to connect the bottom parts, and an internal flange connection is used to connect the top parts. For a top-fed tank equipped with an open end device at the top and a closed end device at the bottom, this means that an overlapping push-in connection is used at the top of the device to connect the top parts, and an internal flange connection is used to connect the bottom parts. For a dual supply tank equipped with an open ended device at the top and bottom, this means that an overlapping push-in connection is used near the top and bottom of the device, and a connection with internal flanges is used in the middle of the device.

These designs also offer advantages over the use of an overlapping plug-in throughout the device in that they reduce the pressure drop across the device and therefore improve the distribution of the process fluid in the catalyst or sorbent bed. For example, in a top-fed tank equipped with an open end device at the top and a closed end device at the bottom, if the last connection in the device at the open end is an overlapping push-in connection and the remaining connections are internal flange connections, there is a significant improvement. in terms of speed differences and process fluid distribution in the catalyst or sorbent bed.

In another design, the means for controlling the flow of gaseous process fluid into or out of the device is a combination of having more and/or larger and/or less spacing holes in the inner shield in the portion adjacent the open end and using an overlapping plug connection to connecting parts of the device closest to the open end, and connecting to internal flanges further from the open end.

The design of this device also has the potential to provide uniquely shaped connections or bolt patterns on the flanges so that the parts cannot be assembled in the wrong order. In addition, the risk of the device being shifted or tilted in the reaction vessel is reduced.

The device is suitable for use as a distributor or manifold in a radial flow tank. Therefore, the invention includes a radial flow reservoir incorporating such a device.

A radial flow tank can be of any design that has a radial flow part, including an axial-radial flow tank. Such tanks may include a domed cylindrical shell that has a process fluid inlet at one end and a process fluid outlet at the other end. The device described above is connected to an inlet or outlet and extends along the longitudinal axis of the reservoir from one end to the other, providing a central cavity into or from which gaseous process fluid can flow. The reservoir also has an external cavity, which may be continuous or discontinuous, from which process fluid may flow into the outlet, or into which process fluid may flow from the inlet. A layer of catalyst or sorbent can be placed between the central and outer cavities. The gaseous process fluid supplied to the tank through the inlet may enter the outer cavity, then pass radially inward through the catalyst or sorbent bed into the central cavity, in which case the device may be called a manifold, and from the central cavity to the outlet. Alternatively, the gaseous process fluid supplied to the tank through the inlet may enter the central cavity, in which case the device may be called a distributor, then pass radially outward through the catalyst or sorbent bed into the outer cavity, and then from the outer cavity into release.

The device can be used as a collector or distributor, although in a preferred embodiment, the device is a distributor.

A layer of particulate catalyst or particulate sorbent may be placed between the central and outer cavities. The radial thickness of the layer may lie in the range of 0.5–4.0 meters. The particulate catalyst or particulate sorbent has a maximum dimension such as width, diameter or length in the range of 2-25 mm, more preferably 2-15 mm, more preferably 2-7 mm. The catalyst or sorbent particles preferably have an aspect ratio, i. e. the ratio of the largest dimension to the smallest dimension, in the range 1–3.

The layer may be formed by a particulate sorbent such as a hydrogen halide sorbent, an organohalogen sorbent, a sulfur compound sorbent, a mercury sorbent, or an arsenic sorbent. The process fluid may be any gas contaminated with these compounds, such as natural gas, carbon dioxide, refinery off-gases, or mixtures thereof. Preferably, the layer is a particulate catalyst layer. The particulate catalysts may be appropriately selected from pre-reforming catalysts, water gas shift catalysts, methanol synthesis catalysts, ammonia synthesis catalysts, methanation catalysts, and methanol oxidation catalysts. The process fluid for these catalysts can be any mixture of gases suitable for carrying out the reaction over these catalysts. The device and reservoir are particularly well suited for carrying out the reaction of synthesis gas containing hydrogen and carbon dioxide over methanol synthesis catalysts.

If desired, a layer of inert ceramic moldings, such as ceramic balls, may be placed around at least part of the device. The layer depth can be in the range of 50-500 mm, preferably 100-300 mm. The ceramic molded articles may have a maximum dimension such as width, diameter or length in the range of 5-25 mm, preferably 10-15 mm. Ceramic molded articles preferably have an aspect ratio, i. e. the ratio of the largest dimension to the smallest dimension, in the range 1–2. The use of larger holes in the inner screen allows the full depth of the layer to be used for diffusion and mixing of the process fluid jets associated with each hole.

The catalyst or sorbent beds may operate under adiabatic conditions or may be cooled or heated by a heat exchange medium passing through pipes or plates located in the catalyst or sorbent bed. In the context of the present invention, layers with tubular or plate cooling are preferred.

In one preferred embodiment of the invention, the radial flow vessel is a refrigerated radial flow vessel, in particular a radial-flow steam-raising converter (rSRC). In the rSRC, a gaseous process fluid such as synthesis gas passes radially in or out through a particulate catalyst bed that is cooled by a plurality of tubes or plates fed with pressurized boiling water as a coolant. Such reactors are described, for example, in US 4321234.

The invention further includes a method for using a reservoir equipped with the device. Thus, a method of using a reservoir may include the steps of supplying process fluid to an inlet of the reservoir, passing process fluid from the inlet into the interior of the device, passing process fluid from the device radially outward through a bed of catalyst or sorbent into an outer cavity within the reservoir, and passing the process fluid from the outer cavity into the reservoir outlet. The catalyst or sorbent bed is preferably cooled with a coolant passed through pipes or plates located in the catalyst or sorbent bed. Alternatively, the method of using the reservoir may include the steps of supplying process fluid to an inlet of the reservoir, passing process fluid from the inlet into an outer cavity within the reservoir, passing process fluid from the outer cavity radially inward through a layer of catalyst or sorbent into the interior space device and pass the process fluid from the interior of the device to the outlet of the tank. The catalyst or sorbent bed is preferably cooled with a coolant passed through pipes or plates located in the catalyst or sorbent bed.

If the bed is formed from particulate sorbent, the process fluid may be any contaminated process stream containing contaminant removed by the sorbent bed, such as a hydrocarbon-containing gas. Alternatively, the process fluid may be a synthesis gas containing hydrogen.

If the bed is formed from a particulate catalyst, the process fluid may be any process stream containing reactants that react over the catalyst bed. In a preferred embodiment of the invention, the process fluid is a synthesis gas containing hydrogen. The synthesis gas containing hydrogen may be a synthesis gas containing hydrogen and carbon dioxide. Alternatively, the synthesis gas containing hydrogen may be a synthesis gas containing hydrogen and nitrogen.

In one of the preferred embodiments of the invention, the catalyst is a methanol synthesis catalyst, the process fluid is a synthesis gas containing hydrogen, carbon monoxide and/or carbon dioxide, the process is a methanol synthesis process.

The methanol synthesis catalysts are preferably copper-containing methanol synthesis catalysts, in particular the methanol synthesis catalyst is a copper/zinc oxide/alumina particulate catalyst. Particularly well suited catalysts are the magnesium-doped copper/zinc oxide/alumina catalysts described in US 4,788,175.

The synthesis of methanol can be carried out as usual at elevated temperature and pressure, for example, a pressure in the range from 20 to 120 bar abs. and temperature in the range from 130°C to 350°C.

The invention is further described with reference to the drawings, in which:

Fig. 1 is a partial sectional view of a part of a device according to the present invention;

In FIG. 2 is a cross-sectional view of a radial flow tank incorporating the device and shows the preferred arrangement of connections; and

In FIG. 3 is a plot of the radial velocity over height of various devices in a radial flow tank.

Those skilled in the art will appreciate that the drawings are schematic and that other pieces of equipment may be added in accordance with normal chemical engineering practice.

As shown in FIG. 1, a curved outer screen 10 is formed from a plurality of spaced apart parallel V-shaped bars 12 placed vertically on an inner screen 14 comprising three adjacent C-shaped horizontal support members 16, 18, 20. The tops of the V-shaped bars 12 are in contact with the top 22 and bottom 24 flanges of each C-shaped support element. Shelf 26 connects the flanges of each support element. Each shelf has a plurality of spaced circular holes 28. The holes are located on adjacent support members in a triangular pattern. The support elements 16 and 20 each have three evenly spaced holes, the middle support element 18 has two holes, each of which is at the same distance from adjacent holes on adjacent support elements. The tops of the V-shaped bars 12, the flanges 22, 24 and the shelf 26 of each support element form a channel 30 in each support element.

Process fluid, such as synthesis gas, can pass from the interior of the device through openings 28 in support members 16, 18, 20, forming an inner screen 14, into channels 30 between shelves 26 and V-shaped bars 12. Process fluid is also can pass from the channels 30 between spaced apart V-shaped bars 12, forming the outer screen 10, outside the device.

Similarly, process fluid may flow in the opposite direction from outside the device through the outer shield 10 and the inner shield 14 into the interior of the device.

As shown in FIG. 2, a reservoir designed for outward radial flow includes an elongated cylindrical shell 112 positioned vertically and provided with a first domed end 114 at the bottom and a second domed end 116 at the top. The first end 114 has a process fluid outlet pipe 118 coaxial with the vertical axis of the tank. At the second end 116 there is an inlet 120 for the process fluid, also coaxial to the vertical axis of the tank, and next to it is the catalyst loading port 122.

The shell 112 has a perforated cylindrical manifold 124 and a device 126 described herein that acts as a distributor. The collector 124 and the distributor 126 are coaxially located in the shell and are installed between the first non-perforated circular reflective plate 128, located at the first end 114, and the second non-perforated annular reflective plate 130, located at the second end 116. The distributor has an open end formed by the annular plate 130, and a closed end defined by a circular plate 128. A particulate catalyst, such as a particulate methanol synthesis catalyst 132, is disposed between the collector 124, the distributor 126, and the baffle plates 128, 130. The diameter of the circular plate 128 is approximately equal to the diameter of the collector 124. 130 extends from the inner side of the shell 112 to the outer edge of the distributor 126. The outer cavity 134 is formed between the outer side of the collector 124 and the inner side of the shell 112. The Central cavity 136 is formed inside the distributor 126.

Distributor 126 is shown as having a top section in which the outer screen is formed by a plurality of parallel, vertically spaced V-bars. The bottom section drawing has been cut to show the interior of the device. The distributor has three parts. The upper part is connected to the middle part by an overlapping push-in connection 138. The lower part is connected to the middle part by a connection 140 with internal flanges.

During operation, process fluid, such as syngas containing hydrogen and carbon oxides, enters the tank through the process fluid inlet 120, is directed by baffle plate 130 to distributor 126, and then into central cavity 136. Baffle plate 130 prevents bypass of the process fluid. fluid around the layer 132 of the catalyst. From distributor 126, process fluid exits radially outward through catalyst bed 132 into manifold 124 and enters outer cavity 134. This reacted process fluid is then directed from outer cavity 134 to process fluid outlet 118, from where reacted process fluid can be vented.

The invention is further described with reference to the following examples.

Example 1

The pressure profile in the 10 meter distributor shown in Fig. 1 and 2, having 5 parts and 4 compounds, for the methanol synthesis gas was determined using the Bernoulli equation: pressure energy+kinetic energy+potential energy=const; those. P + ½ρv² + ρgh=const

At the distributor inlet, the velocity is maximum and the kinetic energy component is high. The change in potential energy is small, so almost all the decrease in kinetic energy is compensated by an increase in pressure energy.

For a valve having a smooth inner surface (i.e. no flanged connections), this gives a pressure drop across the valve (P _MAX - P _MIN ) = 14 kPa. If internal flanges are used for all connections, there is a large initial pressure drop, approximately 20 kPa, with a smaller pressure drop for each successive flanged connection. If the holes give a pressure drop of 15 kPa, then the pressure inside the lower section of the distributor is lower than the pressure in the catalyst bed corresponding to the adjacent section. This leads to a recirculation of the flow, when some of the gas again flows from the catalyst bed into the lower section of the distributor.

When a combination of an overlapping plug connection at the top and connections with internal flanges at the bottom is used, the overall differential (P _MAX - P _MIN ) is reduced, resulting in better gas distribution in the catalyst bed than when using overlapping plug connections for each section, and much better than using internal flanges for each connection.

In FIG. 3 compares the velocity profile for two cases. The speed profile for the internal flanges in all sections of the valve is shown as a dotted line. The speed profile for the overlapping push-in connection between sections 1 and 2 and the internal flanges for the remaining connections is shown as a solid line. The effect of unwanted recirculation can be seen as negative values of the speed shown by the dotted line. By replacing the first connection with an overlapping plug connection, there is a significant improvement in terms of speed differences. Further in the catalyst bed, the change in flux is even smaller.

Claims (14)

1. An apparatus suitable for use as a distributor or manifold in a radial flow reaction vessel, comprising an open end and rigid columnar portions, each columnar portion comprising a cylindrical outer screen formed from parallel, spaced apart bars, and a perforated inner a screen attached to the outer screen, wherein the inner screen is formed from adjacent perforated support members supporting spaced apart rods, wherein the rigid columnar portions further include means for controlling the flow of gaseous process fluid into or out of the device, wherein the means for controlling flow of gaseous process fluid into or out of the device involves the use of overlapping push-in connections to connect parts of the device in the immediate vicinity of the open end, and wherein internal flanged connections are used to connect I have the parts further away from the open end. 2. Device according to claim 1, wherein the cross section of the rods is round, square, rectangular, triangular or wedge-shaped or polygonal, preferably triangular or wedge-shaped. 3. The device according to claim 2, wherein the triangular or wedge-shaped bars are positioned so that the apex of the triangle or wedge faces inward towards the center of the device. 4. The device according to any one of paragraphs. 1-3, in which the support elements are separated from each other by a maximum distance lying in the range of 1-10 mm, more preferably 2-4 mm. 5. The device according to any one of paragraphs. 1-4, in which the support elements are adjacent, essentially without spacing, and preferably attached to each other. 6. The device according to any one of paragraphs. 1-5, wherein each support member has two spaced apart attachment points and a curved or polygonal portion connecting the attachment points and extending into the interior of the device. 7. The device according to any one of paragraphs. 1-6, in which the support element has a cross section selected from a semi-circular, L-shaped, including the first and second flange, or C-shaped, including the first and second flange, separated by a flange, each flange optionally having a ledge. 8. The device according to any one of paragraphs. 1–7, which is made of parts having a diameter in the range of 0.45–0.65 m. 9. The device according to any one of paragraphs. 1-8, which is made of parts having a length in the range of 1-3 m, preferably 1.5-2.0 m. 10. Tank with radial flow, including the device according to one of paragraphs. 1–9. 11. The radial flow tank according to claim 10, including a domed cylindrical shell containing a process fluid inlet at one end and a process fluid outlet at the other end, a device connected to the inlet or outlet and extending along the longitudinal axis of the tank from one end to to another by providing a central cavity into or from which gaseous process fluid flows, an outer cavity from which process fluid flows into an outlet or into which process fluid flows from an inlet, and a fixed bed of catalyst or sorbent between the central and outer cavities. 12. A radial flow vessel according to claim 10 or 11 containing a methanol synthesis catalyst. 13. Tank with radial flow according to any one of paragraphs. 10-12, wherein the radial flow vessel is a cooled radial flow reaction vessel, preferably a radial flow steam converter. 14. The method of processing synthesis gas containing hydrogen, including the use of a reservoir with a radial flow according to any one of paragraphs. 10–13 containing a catalyst or sorbent.

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