GASLIQUID SEPARATORS - TYPE SELECTION AND DESIGN RULES.doc

DEP 31.22.05.11-Gen.September 2002Page 13DEP 31.22.05.11-Gen.September 2002MANUALGAS/LIQUID SEPARATORS - TYPE SELECTION AND DESIGN RULESDEP 31.22.05.11-Gen.September 2002DESIGN AND ENGINEERING PRACTICEThis document is restricted. Neither the whole nor any part of this document may be disclosed to any third party without the prior written consent of Shell Global Solutions International B.V. and Shell International Exploration and Production B.V., The Netherlands. The copyright of this document is vested in these companies. All rights reserved. Neither the whole nor any part of this document may be reproduced, stored in any retrieval system or transmitted in any form or by any means (electronic, mechanical, reprographic, recording or otherwise) without the prior written consent of the copyright owners.PREFACEDEPs (Design and Engineering Practice) publications reflect the views, at the time of publication, of:Shell Global Solutions International B.V. (Shell GSI)andShell International Exploration and Production B.V. (SIEP)andShell International Chemicals B.V. (SIC)andother Service Companies.They are based on the experience acquired during their involvement with the design, construction, operation and maintenance of processing units and facilities, and they are supplemented with the experience of Group Operating companies. Where appropriate they are based on, or reference is made to, international, regional, national and industry standards.The objective is to set the recommended standard for good design and engineering practice applied by Group companies operating an oil refinery, gas handling installation, chemical plant, oil and gas production facility, or any other such facility, and thereby to achieve maximum technical and economic benefit from standardization.The information set forth in these publications is provided to users for their consideration and decision to implement. This is of particular importance where DEPs may not cover every requirement or diversity of condition at each locality. The system of DEPs is expected to be sufficiently flexible to allow individual operating companies to adapt the information set forth in DEPs to their own environment and requirements.When Contractors or Manufacturers/Suppliers use DEPs they shall be solely responsible for the quality of work and the attainment of the required design and engineering standards. In particular, for those requirements not specifically covered, the Principal will expect them to follow those design and engineering practices which will achieve the same level of integrity as reflected in the DEPs. If in doubt, the Contractor or Manufacturer/Supplier shall, without detracting from his own responsibility, consult the Principal or its technical advisor.The right to use DEPs is granted by Shell GSI, SIEP or SIC, in most cases under Service Agreements primarily with companies of the Royal Dutch/Shell Group and other companies receiving technical advice and services from ShellGSI, SIEP, SIC or another Group Service Company. Consequently, three categories of users of DEPs can be distinguished:1)Operating companies having a Service Agreement with Shell GSI, SIEP, SIC or other Service Company. The use of DEPs by these operating companies is subject in all respects to the terms and conditions of the relevant Service Agreement.2)Other parties who are authorized to use DEPs subject to appropriate contractual arrangements (whether as part of a Service Agreement or otherwise).3)Contractors/subcontractors and Manufacturers/Suppliers under a contract with users referred to under 1) or 2) which requires that tenders for projects, materials supplied or - generally - work performed on behalf of the said users comply with the relevant standards.Subject to any particular terms and conditions as may be set forth in specific agreements with users, Shell GSI, SIEP and SIC disclaim any liability of whatsoever nature for any damage (including injury or death) suffered by any company or person whomsoever as a result of or in connection with the use, application or implementation of any DEP, combination of DEPs or any part thereof, even if it is wholly or partly caused by negligence on the part of Shell GSI, SIEP or other Service Company. The benefit of this disclaimer shall inure in all respects to Shell GSI, SIEP, SIC and/or any company affiliated to these companies that may issue DEPs or require the use of DEPs.Without prejudice to any specific terms in respect of confidentiality under relevant contractual arrangements, DEPs shall not, without the prior written consent of Shell GSI and SIEP, be disclosed by users to any company or person whomsoever and the DEPs shall be used exclusively for the purpose for which they have been provided to the user. They shall be returned after use, including any copies which shall only be made by users with the express prior written consent of Shell GSI, SIEP or SIC. The copyright of DEPs vests in Shell GSI and SIEP. Users shall arrange for DEPs to be held in safe custody and Shell GSI, SIEP or SIC may at any time require information satisfactory to them in order to ascertain how users implement this requirement.All administrative queries should be directed to the DEP Administrator in Shell GSI.TABLE OF CONTENTS1.INTRODUCTION41.1SCOPE41.2SUMMARY OF CHANGES SINCE PREVIOUS EDITION41.3DISTRIBUTION, INTENDED USE AND REGULATORY CONSIDERATIONS51.4DEFINITIONS61.5CROSS-REFERENCES61.6SYMBOLS AND ABBREVIATIONS62.SELECTION CRITERIA FOR GAS/LIQUID SEPARATORS102.1DUTY102.2ORIENTATION102.3COMPONENTS102.4DESIGN BASE112.5SELECTION STRATEGY123.DESIGN RULES153.1VERTICAL KNOCK-OUT DRUM163.2HORIZONTAL KNOCK-OUT DRUM203.3VERTICAL WIREMESH DEMISTER243.4HORIZONTAL WIREMESH DEMISTER293.5VERTICAL VANE-TYPE DEMISTER333.6HORIZONTAL VANE-TYPE DEMISTER423.7VERTICAL SEPARATOR WITH SWIRLTUBE DEMISTER DECK463.8CYCLONE WITH TANGENTIAL INLET (CONVENTIONAL CYCLONE)583.9CYCLONE WITH STRAIGHT INLET AND SWIRLER ("GASUNIE" CYCLONE)643.10VERTICAL SEPARATOR WITH REVERSED-FLOW MULTICYCLONE BUNDLE (CONVENTIONAL MULTICYCLONE)673.11VERTICAL SEPARATOR WITH AXIAL-FLOW MULTICYCLONE BUNDLE (WITH RECIRCULATION OF SECONDARY GAS)723.12HORIZONTAL SEPARATOR WITH AXIAL-FLOW MULTICYCLONE BUNDLE (WITH RECIRCULATION OF SECONDARY GAS)733.13FILTER SEPARATOR744.PIPING REQUIREMENTS785.REFERENCES79APPENDICESAPPENDIX INATURE OF THE FEED80APPENDIX IISIZING OF THE FEED AND OUTLET NOZZLES84APPENDIX IIIDESIGN OF SCHOEPENTOETER (VANE-TYPE) INLET DEVICE86APPENDIX IVDESIGN MARGINS FOR SEPARATOR DESIGN91APPENDIX VLEVEL CONTROL92APPENDIX VIVESSEL GEOMETRICAL RELATIONSHIPS94APPENDIX VIISIZING OF SEPARATOR VESSELS98APPENDIX VIIIMISTMAT SPECIFICATIONS103APPENDIX IXVANE PACKS104APPENDIX XVESSEL SIZING EXAMPLES106APPENDIX XIDEBOTTLENECKING TIPS1131.INTRODUCTION1.1SCOPEThis DEP specifies requirements and gives recommendations for the selection and design of gas/liquid separators.Design rules for the following types of separators are given in (Section 3):-Knock-out drum (vertical and horizontal separator)-Wiremesh demister (vertical and horizontal separator)-Vane-type demister (vertical and horizontal separator)-Separators of the SMS family (SMS, SVS, SMSM)-Cyclone with tangential inlet (conventional cyclone)-Cyclone with straight inlet and swirler ("Gasunie" cyclone)-Vertical multicyclone separator with reversed-flow multicyclone bundle (conventional multicyclone separator)-Filter separator NOTEThe design of gas/liquid/liquid three-phase separators is excluded from the scope of this DEP; for this subject, DEP 31.22.05.12-Gen. should be consulted.Users of this DEP should first consult Section 2 ("Selection Criteria for Gas/Liquid Separators") to familiarise themselves with the general design philosophy and the characteristics of the various separators.After selection of the desired separator the design rules can be obtained from Section 3.Further guidance for debottlenecking of existing separators is given in Appendix XI.This is a revision of the DEP of the same number dated December 1996. A summary of the main changes is given in (1.2).1.2SUMMARY OF CHANGES SINCE PREVIOUS EDITIONThe previous edition of this DEP was dated December 1996. Other than editorial changes, the following are the main changes since that edition:SectionChange2.5Added FS (filter separator). Removed VAMC, HAMC and HTFS.3.1.5Added requirement to include Schoepentoeter pressure drop3.5Added option for two-stage separator with vertical flow vane pack (3.5.7)3.5.1Added pressure limitation.Figure 3.6Added vertical flow separator.3.7Development of these (vertical separators with swirl tube demister decks) has been resumed, with an aim to further increasing the gas and liquid handling capacity. Design information limited to overall sizing.3.7.6Swirldeck requirements refined.3.7.7Secondary mistmat requirements refined.3.7.8Changed substantially.3.7.9Changed substantially.3.7.11Changed substantially.3.9.1Changed characteristics and non-recommended applications.3.11Vertical separator with axial multicyclone bundle (with recirculation of secondary gas) has been removed. This type of separator is no longer supported. Some caveats are given.3.12Horizontal separator with axial-flow multicyclone bundle (with recirculation of secondary gas) has been removed. This type of separator is no longer supported. Some caveats are given.3.13Now focused on single stage vertical filter separator. Horizontal two-stage filter separator no longer supported. Appendix IIFeed inlet nozzle - added pressure drop correlation for a Schoepentoeter.Removed specimen copy of Standard Drawing S 10.010 (users should refer to the latest version of the Standard Drawing).Appendix IIIDesign procedure of Schoepentoeter inlet devices (types I to IV) modified in accordance with latest philosophy.Removed specimen copies of Standard Drawings S 20.015, S20.016, S20.017, S20.019, S 20.020, S 20.021 and S20.022 (users should refer to the latest version of the Standard Drawings).Removed specimen copy of data/requisition sheet DEP31.20.41.93Gen. (users should refer to the latest version of the data/requisition sheet).Appendix VIIIRemoved specimen copy of data/requisition sheet DEP31.22.05.93Gen. (users should refer to the latest version of the data/requisition sheet).Removed specimen copies of Standard Drawings S 20.028, S20.029 and S20.030 (users should refer to the latest version of the Standard Drawings).Appendix IXAdded specifications of the BM/KCH hollow vane.Appendix X.1Added requirement for design margin.Appendix X.2Added requirement for design margin.Appendix X.3.2Changed substantially.Appendix X.3.6Removed requirement regarding drain pipe check.Appendix XIChanged substantially.1.3DISTRIBUTION, INTENDED USE AND REGULATORY CONSIDERATIONSUnless otherwise authorised by Shell GSI and SIEP, the distribution of this document is confined to companies forming part of the Royal Dutch/Shell Group managed by a Group company and to Contractors nominated by them (i.e. the distribution code is "C", as described in DEP00.00.05.05-Gen.).Attention is drawn to the copyright and confidentiality statements on the title page and preface of this DEP and to the fact that some of the referenced documents cover Shellproprietary items.This DEP is intended for use in oil refineries, chemical plants, gas plants, exploration and production facilities and supply and marketing installations.If national and/or local regulations exist in which some of the requirements may be more stringent than in this DEP, the Contractor shall determine by careful scrutiny which of the requirements are the more stringent and which combination of requirements will be acceptable as regards safety, economic and legal aspects. In all cases the Contractor shall inform the Principal of any deviation from the requirements of this document which is considered to be necessary in order to comply with national and/or local regulations. The Principal may then negotiate with the Authorities concerned with the object of obtaining agreement to follow this document as closely as possible.1.4DEFINITIONSThe Contractor is the party which carries out all or part of the design, engineering, procurement, construction, commissioning or management of a project or operation of a facility. The Principal may undertake all or part of the duties of the Contractor.The Manufacturer/Supplier is the party which manufactures or supplies equipment and services to perform the duties specified by the Contractor.The Principal is the party which initiates the project and ultimately pays for its design and construction. The Principal will generally specify the technical requirements. The Principal may also include an agent or consultant authorised to act for, and on behalf of, the Principal.The word shall indicates a requirement.The word should indicates a recommendation.1.5CROSS-REFERENCESWhere cross-references are made, the number of the section or sub-section referred to is shown in brackets.All documents referenced in this DEP are listed in (5.).1.6SYMBOLS AND ABBREVIATIONSUnless explicitly stated otherwise, all symbols used in this DEP are expressed in the units given below: Aaream2ArArchimedes number:-alength of side, square cyclone inlet (Type 1)mCspecific heatJ/kg.KDinternal diameter of vessel or large pipemddiameter of small pipe, nozzle, bubble or droplet mEavailable clearance for SchoepentoetermEffefficiency: Eff = ( QL,out/QL,in ) * 100%FrGgas Froude number:-FrLliquid Froude number:-fderating factor-GORgas / oil ratioN(ormal)m3/m3gacceleration due to gravitym/s2Hheightmhheight of vessel for liquid hold-up (to LZA(HH)mKfriction loss factor-LlengthmLA(H)high level pre-alarmLA(L)low level pre-alarmLZA(HH)high level tripLZA(LL)low level tripMmass flow ratekg/smax(x,y) maximum of the values x and y MWmolecular weightkg/kmolNFAnet free area-NLnormal levelnnumber of vanes (Schoepentoeters), cyclones, etc.-PpressurePappressurePaQvolumetric flow ratem3/sRradius of vane (Schoepentoeters)mRcyclone scrollmRgas constant (R = 8314 J/kmol.K)J/kmol.Kswidth of split between cyclone bottom plate and wallmSMSSchoepentoeter Mistmat SwirldeckSMSMSchoepentoeter Mistmat Swirldeck MistmatSVSSchoepentoeter Vane SwirldeckTabsolute temperatureKtthicknessmVvolumem3vvelocitym