design and rating of packed distillation columns

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Design and Rating of Packed Distillation Columns 0 INTRODUCTION/PURPOSE 1 SCOPE 2 FIELD OF APPLICATION 3 DEFINITIONS 4 DESIGN PHILOSOPHY 5 PERFORMANCE GUARANTEES 6 DESCRIPTION OF PACKED COLUMN INTERNALS 7. DESIGN CALCULATIONS 7.1 Selection of Packing Size 7.2 Rough Design 7.3 Detailed Design and Rating 8 LIQUID DISTRIBUTION AND REDISTRIBUTION 8.1 Basic Concepts 8.2 Pour Point Density 8.3 Peripheral Irrigation - the Wall Zone 8.4 Distributor Levelness 8.5 Maximum Bed Height and Liquid Redistribution 9 PRACTICAL ASPECTS OF PACKED COLUMN DESIGN 9.1 Packing 9.2 Support Grid 9.3 Liquid Collector 9.4 Liquid Distributor or Redistributor 9.5 Packing Hold-down Grid 9.6 Reflux or Feed Pipe 9.7 Reboil Return Pipe 9.8 Liquid Draw-offs 9.9 Vapor Draw-offs 10 BIBLIOGRAPHY APPENDICES A DEFINITIONS A.1 INTRODUCTION A.2 MECHANICAL DEFINITIONS A.3 PERFORMANCE DEFINITIONS B PACKING HYDRAULICS - THE NORTON METHOD TABLES 1 PACKING FACTORS FOR THE MORE COMMON RANDOM PACKINGS

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  • 1. GBH Enterprises, Ltd.Process Engineering Guide: GBHE-PEG-MAS-612Design and Rating of Packed Distillation Columns 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 gives no warranty as to the fitness of this information for any particular purpose and any implied warranty or condition (statutory or otherwise) is excluded except to the extent that exclusion is prevented by law. GBHE accepts no liability 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

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Process Engineering Guide:Design and Rating of Packed Distillation ColumnsCONTENTSSECTION0INTRODUCTION/PURPOSE31SCOPE32FIELD OF APPLICATION43DEFINITIONS44DESIGN PHILOSOPHY45PERFORMANCE GUARANTEES56DESCRIPTION OF PACKED COLUMN INTERNALS67DESIGN CALCULATIONS77.1 7.2 7.3Selection of Packing Size Rough Design Detailed Design and Rating7 7 9Refinery 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 3. 8LIQUID DISTRIBUTION AND REDISTRIBUTION128.1 8.2 8.3 8.4 8.5Basic Concepts Pour Point Density Peripheral Irrigation - the Wall Zone Distributor Levelness Maximum Bed Height and Liquid Redistribution12 13 13 13 149PRACTICAL ASPECTS OF PACKED COLUMN DESIGN149.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 9.9Packing Support Grid Liquid Collector Liquid Distributor or Redistributor Packing Hold-down Grid Reflux or Feed Pipe Reboil Return Pipe Liquid Draw-offs Vapor Draw-offs14 15 16 17 21 21 23 23 2310BIBLIOGRAPHY25APPENDICESADEFINITIONS26A.1INTRODUCTION26A.2MECHANICAL DEFINITIONS26A.3PERFORMANCE DEFINITIONS26BPACKING HYDRAULICS - THE NORTON METHOD30Refinery 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 4. TABLES1PACKING FACTORS FOR THE MORE COMMON RANDOM PACKINGS32Refinery 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 5. FIGURES 1PACKED COLUMN - GENERAL ARRANGEMENT62LIQUID AND VAPOUR LOAD CONSTANTS, KL & KV, FOR TRIAL DIAMETER CALCULATION83PLATE EFFICIENCY CORRELATION OF O'CONNE104DIAGRAMMATIC ARRANGEMENT OF GAS-INJECTION SUPPORT155LIQUID COLLECTORS - VANE AND CHIMNEY TYPES166MULTI-SPRAY DISTRIBUTORS177LADDER OR PIPE LATERAL188ORIFICE DRIP PANS189NOTCHED TROUGH DISTRIBUTOR1910ORIFICE TROUGH DISTRIBUTOR2011TWO PHASE FEEDS2212VAPOR SPARGER2413GENERALIZED PRESSURE DROP CORRELATION FOR RANDOM DUMPED PACKINGS30DOCUMENTS REFERRED TO IN THIS PROCESS ENGINEERING GUIDE45Refinery 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 6. 0INTRODUCTION/PURPOSEGBHE does not manufacture packings or the associated column internals - they are purchased from specialist manufacturers. The detailed design of the packings and internals is undertaken by the manufacturers. In most cases, competitive bids are sought from various manufacturers. The role of the Process Engineer is to: (a)specify the process requirements, in the form of data sheets;(b)ensure that what is offered by the bidding manufacturers will meet these requirements; and(c)compare the designs offered on technical merit; outstanding features of a particular design may outweigh any additional cost which may be incurred.On existing plant there is often the need to assess the performance of packed columns for several reasons: (d)to assess the reasons for any shortfall in performance, compared with design or earlier operation;(e)to assess uprating capability of the existing packings and liquid distributors, from high rate plant trials; or(f)to explore modifications for operation at higher or lower rates.Packings are made in metal, ceramic and plastic; the vast majority of distillation applications use metal packings. Ceramic packings tend to give problems of breakage in service. They are used in corrosive services. Few plastics can tolerate the temperatures encountered in distillation. Three families of packings exist: random, structured and grid packings. Random packings are the traditional ones and various non-proprietary types are available; newer high performance random packings have been developed, but all are proprietary. Structured packings are the newest ones and most of these are proprietary. Grid packings are not generally used for distillation, because of poor efficiency, but can be useful in fouling services.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 7. The design for proprietary packings and especially structured packings depends on the design methods supplied by their manufacturers. These design methods are sometimes unreliable and expert advice should be sought when considering proprietary packings. This Guide has been prepared for GBH Enterprises.1SCOPEThis Guide deals with the design and rating of packed distillation columns. It covers neither guidance on the selection of trays and packings nor some aspects of their performance characteristics; advice on both of these is given in GBHEPEG-MAS-610 - Selection of Internals for Distillation Columns. Guidance is also given on the assessment of liquid distributors - the detailed design of distributors requires specialist knowledge and experience not available in GBHE, though we are able to check some of the more critical aspects of design. Also, some of the more important practical issues are discussed. The scope of the guide is summarized in its clause headings: 4 5 6 7 8 9Design Philosophy Performance Guarantees Description of Packed Column Internals Design Calculations Liquid Distribution and Redistribution Practical Aspects of Packed Column DesignIn addition, Appendices give examples of design calculations by various methods for both ran