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EP-4739428-A1 - REACTOR LOADING FOR EFFICIENT FLOW DISTRIBUTION

EP4739428A1EP 4739428 A1EP4739428 A1EP 4739428A1EP-4739428-A1

Abstract

The present disclosure relates to a reactor having an inlet above an outlet, containing a catalyst bed comprising multiple layers of material, in the following order from inlet to outlet, a first layer of material providing a flow resistance corresponding to a pressure drop per meter of dpm 1 , a second layer providing a flow resistance corresponding to a pressure drop per meter of dpm 2 , wherein the combined height of the first layer and the second layer is at least 4 m, wherein the height of the second layer is at least 0.5 m, wherein the pressure drop per meter of the second layer dpm 2 is at least 20% above the pressure drop per meter of the first layer dpm 1 , and wherein the first layer, the second layer and optionally the third layer are supported by a single catalyst support. This has the associated benefit of providing an active redistribution of liquid flow, without the requirement of internals, except the single catalyst support under the multiple layers of catalyst.

Inventors

  • MALDONADO RUIZ, Xavier Enrique
  • NYMANN, Peter Andreas

Assignees

  • Topsoe A/S

Dates

Publication Date
20260513
Application Date
20240705

Claims (12)

  1. [Claim 1] A reactor having an inlet above an outlet, containing a catalyst bed comprising multiple layers of material, in the following order from inlet to outlet, a first layer of material providing a flow resistance corresponding to a pressure drop per meter of dpmi, a second layer providing a flow resistance corresponding to a pressure drop per meter of dpm 2, wherein the combined height of the first layer and the second layer is at least 4 m, wherein the height of the second layer is at least 0.5 m, wherein the pressure drop per meter of the second layer dprri2 is at least 20% above the pressure drop per meter of the first layer dpmi, and wherein the first layer, the second layer and optionally further layers are supported by a single catalyst support.
  2. [Claim 2] The reactor of claim 1 further comprising a third layer of porous material providing a flow resistance corresponding to a pressure drop per meter dpms, positioned below the second layer, wherein the material of the third layer comprises a porous refractory support and a catalytical active metal, wherein the pressure drop per meter of the second layer is at least 20% above the pressure drop per meter provided by the third layer.
  3. [Claim 3] The reactor of claim 1 or 2 wherein the material of the first layer, the material of the second layer or the material of the third layer if present, such as the material of multiple of these layers or all of these layers comprises a porous refractory support and a catalytical active metal.
  4. [Claim 4] The reactor of any preceding claim, wherein the shape of the reactor is substantially that of a vertical cylinder, with a ratio between the height of the first layer and the diameter being less than 4:1 .
  5. [Claim 5] The reactor of any preceding claim, wherein the shape of the reactor is substantially that of a vertical cylinder, with a ratio between the combined height of the first layer, the second layer and if present the third layer of porous material and diameter being more than 4: 1 , such as 5:1 or 6: 1.
  6. [Claim 6] The reactor of any preceding claim wherein shape of the reactor is substantially that of a vertical cylinder, with a ratio between the combined height of the first layer, the second layer and if present the third layer of porous material and diameter being less than 10:1 , such as 8: 1 or 7: 1.
  7. [Claim 7] The reactor of any preceding claim, wherein at least 50% of the porous material of at least one of the first layer, the second layer and if present the third layer, has an average dimension along the shortest axis being 0.1 mm, 0.5 mm, 1 mm to 3 mm or 5 mm and an average dimension along the longest axis relative to the average dimension along the shortest axis being from 1 :1 to 20: 1 .
  8. [Claim 8] The reactor of any preceding claim, wherein at least 50% of the porous material of at least one, such as multiple or all of the first layer, the second layer and if present the third layer, has a shape being quadrolobe, trilobe, ring shaped or cylindrical.
  9. [Claim 9] The reactor of any preceding claim, wherein at least 50% of the porous material of at least one, such as multiple or all of the first layer, the second layer and if present the third layer, is an extruded material.
  10. [Claim 10] The reactor of any preceding claim, wherein the weight concentration of each catalytically active metal of the material of the first layer, the material of the second layer and if present the material of the third layer differs by less than 20% of the total weight concentration of catalytically active metals, but the size or shape is different between the zones.
  11. [Claim 11] The reactor of any preceding claim, wherein the catalytically active metal of the material of zone 1 and the material of zone 2 or if present zone 3 is active in hydrocracking, and optionally containing a zeolite or a molecular sieve.
  12. [Claim 12] A method of flow redistribution in a fixed bed reactor having a liquid inlet above a liquid outlet, comprising the steps of providing a first layer of material positioned above a second layer of material in a single bed support by a single catalyst support, wherein the combined height of said first layer of material and said second layer of material is at least 4 m, wherein the height of the second layer is at least 0.5 m, wherein the pressure drop per meter over said second layer of material is at least 20% higher than the pressure drop per meter over said first layer of material.

Description

Description Title of Invention: Reactor loading for efficient flow distribution Technical Field [0001 ] The present disclosure relates to the field of chemical engineering, and specifically to efficient management of flows in large fixed-bed reactors, such as trickle bed reactors. Background Art [0002] To ensure maximum employment of reactor volume in a catalytic reactor, efficient distribution of reactants and thermal energy is required, especially for large reactors. [0003] Commonly mechanical equipment such as charge distributors are installed to redistribute the feed, product and energy, but such equipment is costly and takes up reactor space. Summary of Invention [0004] To enable efficient distribution of reactant and efficient use of reactor volume we propose loading catalytically active materials, such that a local resistance to flow, and thus a pressure drop, is created, in order to force increased radial distribution of flow. This resistance of flow is provided by having a reactor zone in which the flow resistance is lower, e.g. by smaller catalyst particles. As the flow enters the region of more resistance, radial diffusion will increase and the flow will be redistributed, such that the radial variation of composition and temperature is reduced. Technical Problem [0005] In a chemical reaction the availability of reactant, temperature and thermal energy defines the extent of reaction. [0006] In many industrial applications, some or all reactants are typically in the liquid phase, and a suitable catalyst is required to facilitate the desired chemical reactions. In order to ensure that the reactants come into contact with the catalyst efficiently and uniformly, a liquid distributor is often used to distribute the reactants evenly across the catalyst bed. [0007] A common reactor design is a vertical, cylindrical reactor, filled with catalytic particles, in which liquids and gases react. Commonly liquid reactants will enter at the top of such a reactor and exit at the bottom, while gaseous reactants may be either in co-flow or counter-flow. Theoretically, the distribution is uniform, due to the random loading of multiple small particles, but in practice, inflow or loading characteristics may result in regions with higher reaction, and even blockages, which may further increase the lack of uniformity in the reaction, by local conditions causing deposition of solids on the catalyst surfaces, hindering flows. [0008] To minimize such maldistribution, it is common practice to redistribute the flowing gas and liquid at regular intervals, for example by providing the reactor with one or more mechanical redistribution trays along the cylinder axis. Such a tray will however take up reactor volume, and thus reduce the conversion capacity of the reactor, and therefore it is desirable to provide such redistribution, without sacrificing reactor volume. [0009] The evaluation of redistribution is commonly made by evaluation of temperature gradients in a reactor, since temperature measurements are inexpensive and with rapid response, and for exothermal reactions the temperature measurement also reflects maldistribution and uneven reactivity. [0010] US 3,732,078 discloses redistribution of reactor flow by a deflector followed by large size solid particles and evaluates the effect by evaluation of bulk catalyst performance. [0011] US 9,732,774 follows a similar approach, in which a reactor comprises processing zones and a redistribution zone, in which the processing zones are illustrated as comprising large, high void, materials, and the effect is tested by distribution of water flow in a reactor. [0012] Evaluation of such redistribution methods using an open redistribution zone made on reactors in operation have shown that the temperature variation across the reactor is unsatisfactorily high, and a way of enabling a lower radial temperature variation are desired. Definitions [0013] In the following a cylindrical catalytic reactor shall be construed as a mechanical unit having a central substantially cylindrical part positioned with a substantially vertical axis, at least one inlet and one outlet position, and containing an amount of catalyst particles and optionally mechanical elements and non-catalytic particles. The substantially cylindrical part may be configured with upper and lower ends at which the inlet and outlet may be positioned. The ends may be dome shaped and the reactor may typically be prepared for elevated pressure up to several MPa. The reactor may have additional inlet and outlets commonly positioned at the perimeter of the cylinder. The reactor size may commonly be from 3 m diameter to 5 m diameter and the height may be from 10 m to 40 m or more. [0014] The reactor may receive a one phase liquid or gaseous flow or it may be receiving or producing a two phase flow of liquid and gas. [0015] If the reactor flow is a two phase flow the reactor may be of the type called trickle bed reactor in which a