Hydrogenation Reactor Design Considerations
Upcoming SlideShare
Loading in...5
×
 

Hydrogenation Reactor Design Considerations

on

  • 1,673 views

Fixed Bed Reactor Internals ...

Fixed Bed Reactor Internals
Inlet Distributor Design
Debris Collector Design
Inert Balls
Catalyst Separation Screens
Catalyst Bed Supports
Outlet Collector
Liquid Re-distributor
Catalyst Un-Loading Connections
Void Space

Statistics

Views

Total Views
1,673
Views on SlideShare
1,673
Embed Views
0

Actions

Likes
2
Downloads
76
Comments
0

0 Embeds 0

No embeds

Accessibility

Categories

Upload Details

Uploaded via as Adobe PDF

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

Hydrogenation Reactor Design Considerations Hydrogenation Reactor Design Considerations Document Transcript

  • Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com GBHE Technical Bulletin CTB #10 HYDROGENATION REACTOR DESIGN Fixed Bed Reactor Internals The following is designed to give an overview on and some insight in the general design features of hydrogenation reactors and the impact of the various reactor internals on performance. GBHE can offer assistance in the design and alteration of hydrogenation reactors and their internals to meet specific production and engineering needs. It should be noted that specific advice can only be given on a case to case basis. For more information, please contact GBHE outlet collector graded catalyst inert supports catalyst separation screens separation screen debris collector void space inlet distributor inert balls catalyst bed liquid redistributor if required catalyst unloading
  • Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com INLET DISTRIBUTOR Reactors operate in different flow regimes within the catalyst bed. In normal operation, however, there are only three conditions that affect inlet design, viz. gas phase, liquid phase and mixed phase flow regimes. With gas flows, inlet velocities are sometimes high and inlet baffles are used to prevent direct impingement on the reactor bed. These baffles are located on the reactor centre line and can be as simple as a set of concentric rings with a cover plate. Mixed phase flow distributors are more complicated and are covered elsewhere. The mixed phase flow designs will be the same for the reactor inlet and a distribution tray. In some high velocity applications it may be necessary to include both an impingement baffle and a two-phase flow distributor. DEBRIS COLLECTOR Reactors contain debris collectors for two reasons: 1. To provide an increased area for fluid flow. 2. To collect trash and any 'tramp material' which can be caught in the baskets. They will collect millscale from furnaces, storage tanks and exchangers and still allow the feed stream to pass. In chemical reactors with clean feed streams these baskets may not be required. They are typically made from 100 mm diameter baskets of mesh or perforated plate which is approximately 150 to 200 mm long. They are located triangularly in an inert bed of alumina balls and are tied together in hexagonal clusters. As many baskets as possible are fitted into the reactor on a 180 to 200 mm pitch. Further advice can be given for design of reactor internals if required. Please contact GBHE
  • Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com INERT BALLS (top of bed) It is possible to include a layer of inert ceramic balls directly below the inlet. This can be a single size or random distribution size material. They protect the catalyst bed from direct impingement of the inlet feedstock stream. The layer is usually 0.15 metres in depth unless a greater depth is needed for the inlet debris collector if used. The ceramic material is usually alumina. Typically, the balls have a diameter of 12.5 mm. A screen is sometimes included below the layer of inert ceramic material to prevent the more dense balls from sinking into the catalyst bed during normal operation. Further advice can be given for design of reactor internals if required. Please contact GBHE CATALYST SEPARATION SCREENS (top of bed) The separation screen keeps the ballast out of the catalyst bed. The screen is cut into segments to pass through the manhole and laced together inside to form a complete circle. The screen is not attached to the reactor and is free to settle with the bed during the run. It falls with the catalyst when the latter is unloaded. Typical screen sizes are given in Table C2 PT-1. Table C2 PT-1. Screen sizes for Vulcan Series VIG catalysts. Typical values. VIG-T02 1.2 mm VIG-T03 2.5 mm Separation Screen Mesh size 18x18 mm wire diameter 0.58 mm (0.023") width of opening 0.83 mm (0.0326") 34.4% open area mesh size 12x12 mm wire diameter 0.89 mm (0.035") width of opening 1.22 mm (0.048") 33.2% open area
  • Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com Further advice can be given for design of reactor internals if required. Please contact GBHE CATALYST BED GBHE VULCAN Series VIG catalysts are HGS shaped catalyst. They can be dense or sock loaded. When used in existing vessels or in new units, there are some factors that need to be taken into consideration to make optimum use of the catalyst activity. Design of the reactor internals is part of this performance maximization. GBHE offers to advise wherever possible and make process recommendations for various options. Manholes have not been shown in Figure 1. They are, however, an important factor in new reactors. Further details are available on request. In general, manholes can be located in the centre line or on the side of the vessel and can vary in size from 400 to 600 mm. Similarly, catalyst drop out nozzles are required. Usually, dimensions are comparable to those for manholes. Further advice can be given for design of reactor internals if required. Please contact GBHE CATALYST SEPARATION SCREENS (bed support) A fine screen whose opening is less than the catalyst size is sometimes used between the catalyst and the inert support. It prevents catalyst pieces and fines generated during normal operation from reaching the outlet and are designed to have a maximum open surface area and will not seriously affect the total reactor pressure drop. The fine mesh is not usually strong enough to span the bed on top of the inert fill. Any distortion or movement of the screen will allow catalyst to by-pass and may cause rupture of the fine material. It is therefore necessary to include a second screen to ensure that weaker screen does not bend and/or rupture. The lower screen is usually sized to prevent the smallest of the inert balls from passing through (see also reference for inert support loading).
  • Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com Table C2 PT -2. Screen sizes for VULCAN Series VIG catalysts. Typical values. VIG-T02 VIG-T03 Top Screen (catalyst support) Mesh size 18x18 wire diameter 0.58 mm (0.023") Width of opening 0.83 mm (0.0326") 34.4% open area mesh size 12x12 wire diameter 0.89 mm (0.035") width of opening 1.22 mm (0.048") 33.2% open area Bottom Screen Mesh size 8 x 8 Wire diameter 1.2 mm (0.047") Width of opening 1.98 mm (0.078") 38.9% open area Mesh size 8 x 8 Wire diameter 1.2 mm (0.047") Width of opening 1.98 mm (0.078") 38.9% open area In some cases, a single bed can be split into two or more sections by separation screens. Further advice can be given for design of reactor internals if required. Please contact GBHE
  • Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com CATALYST BED SUPPORTS There are a number of methods for bed supports. These include a grating and beam arrangement, proprietary screens or inert fill. The method covered here it the application of inert balls. An outlet collector must be used when using an inert fill system. The material usually is high purity α- alumina. The philosophy is to use a layered fill. The layer directly beneath the catalyst should be approx. twice the catalyst size. The bottom layer should be approx. 1.3 - 2.5 cm thick (½ - 1"). The balls should cover the outlet collector by a minimum of 7.6 cm (3") and should be at least 7.6 cm (3") into the straight part of the shell. Typical support system data for VULCAN Series VIG catalysts are given in table C2 PT-3. Table C 2 PT-3 VIG-T02 VIG-T03 Top layer below catalyst bed (15.2 cm (6") depth) 3.2 mm (1/8") 3.2 mm (1/8") Next layer below top balls (15.2 cm (6") depth) 6.4 mm (1/4") 6.4 mm (1/4") Bottom layer below second layer (fill rest of the volume) 12.7 mm (1/2") 12.7 mm (1/2") Where a second bed is used, it may be necessary to use a grating and a beam. In case alumina balls are used, they should be sized according to the values given in table C2 PT -2. Table C 2 PT-4 VIG-T02 VIG-T03 Top layer below catalyst bed (7.6-15.2 cm (3-6") depth) 3.2 mm (1/8") 3.2 mm (1/8") Next layer below top balls (7.6-15.2 cm (3-6") depth) 6.4 mm (1/4") 6.4 mm (1/4") Bottom layer below second layer (fill rest of the volume) 12.7 mm (1/2") 12.7 mm (1/2")
  • Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com Further advice can be given for design of reactor internals if required. Please contact GBHE OUTLET COLLECTOR A gas outlet collector is used whenever an inert fill support material is used. It is essential that the inert support goes into the straight part of the vessel. The outlet collector must be submerged in the inert support material and essentially not protrude into the catalyst bed. The inert support and outlet collector both keep the liquid/gas flow evenly distributed across the bottom of the reactor. Without these, the fluid flow would tend to move toward the outlet nozzle before passing through the whole of the bed. The screen and support which make up the collector can take up a large space in the bottom of the reactor. Therefore, layout and design have to be checked to ensure optimum design is feasible. The basic design is a 3x3 mesh with a wire diameter of 2.0 mm. Support bar spacing is such that it prevents collapse with the design pressure drop. Further advice can be given for design of reactor internals if required. Please contact GBHE LIQUID REDISTRIBUTOR The liquid redistributor is used to ensure equal loading of liquid and vapour at the top of the catalyst bed. It is a perforated tray with chimneys and chimney cover. The principle of a typical redistributor is shown in figure C2 PT-3. The holes are sized to give a liquid head on the tray. This will depend on the variation expected to cover the full range of applied liquid flow rates. The number of chimneys is set by the gas flow. The chimney covers are sized to overhang the chimney and prevent liquid passing straight down the chimneys. The distributors are used at the bed inlet as redistributors in a multiple bed system. An inlet baffle is commonly used to prevent direct impingement.
  • Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com Figure C2 PT -3 Further advice can be given for design of reactor internals if required. Please contact GBHE CATALYST UNLOADING CONNECTIONS The drop out nozzle is filled with inert support balls. Typically a 15.2 cm (6") pipe is used as drop out nozzle. It has a removable length which projects into the vessel. The extended pipe length reaches up to the catalyst bed. For a bed supported on beams a 30.5 cm (12") manhole is typical. The bottom of the nozzle is flush with the bottom of the catalyst bed. Both methods need a protective internal cover which stops if the opening cover is removed accidentally. Further advice can be given for design of reactor internals if required. Please contact GBHE Perforated Tray
  • Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com VOID SPACE The use in void space is allowed in reactor design to allow access to the top of the reactor. It also avoids direct impingement of the inlet streams onto the packed surface if no other internals are used. A void space will also be included if the reactor is split into two beds. This allows access to both beds. Typical void spaces depend on reactor diameter and applied internals. Values can be given after full review of the reactor vessel sketches and process conditions. Further advice can be given for design of reactor internals if required. Please contact GBHE. Information contained in this publication or as otherwise supplied to Users is believed to be accurate and correct at time of going to press, and is given in good faith, but it is for the User to satisfy itself of the suitability of the information for its own particular purpose. GBHE accepts no liability for loss or damage or personnel injury caused by or resulting from reliance on this information. Freedom under Patent, Copyright and Designs cannot be assumed.
  • Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com