DEP 31.22.01.31-Gen.pdf

TECHNICAL SPECIFICATION ROTATING DISC CONTACTORS DEP 31.22.01.31-Gen. December 1995 DESIGN AND ENGINEERING PRACTICE This document is confidential. Neither the whole nor any part of this document may be disclosed to any third party without the prior written consent of Shell International Oil Products B.V. and Shell International Exploration and Production B.V., The Hague, 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. PREFACE DEP (Design and Engineering Practice) publications reflect the views, at the time of publication, of: Shell International Oil Products B.V. (SIOP) and Shell International Exploration and Production B.V. (SIEP) and Shell International Chemicals B.V. (SIC) The Hague, The Netherlands, and other 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, national and international standards and codes of practice. 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 SIOP, 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 SIOP, SIEP or SIC. Consequently, three categories of users of DEPs can be distinguished: 1)Operating companies having a Service Agreement with SIOP, 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. 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, SIOP, 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. The benefit of this disclaimer shall inure in all respects to SIOP, 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 SIOP 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 SIOP and SIEP. The copyright of DEPs vests in SIOP and SIEP. Users shall arrange for DEPs to be held in safe custody and SIOP or SIEP 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 SIOP. NOTE: In addition to DEP publications there are Standard Specifications and Draft DEPs for Development (DDDs). DDDs generally introduce new procedures or techniques that will probably need updating as further experience develops during their use. The above requirements for distribution and use of DEPs are also applicable to Standard Specifications and DDDs. Standard Specifications and DDDs will gradually be replaced by DEPs. DEP 31.22.01.31-Gen. December 1995 Page 2 TABLE OF CONTENTS 1.INTRODUCTION.5 1.1SCOPE 5 1.2DISTRIBUTION, INTENDED USE AND REGULATORY CONSIDERATIONS5 1.3DEFINITIONS 5 1.4CROSS-REFERENCES6 2.GENERAL DESCRIPTION OF AN RDC.7 3.BASIC DESIGN REQUIREMENTS.8 4.DESIGN AND ENGINEERING9 4.1VESSEL. 9 4.2GRIDS AND SLEEVES.9 4.3ROTOR ASSEMBLY AND BEARINGS.10 4.4ROTOR SHAFT SEALING10 4.5DRIVING UNIT12 4.6STEAM COILS.13 4.7INSULATION AND FIREPROOFING13 4.8TOLERANCES14 5.NOISE CONTROL.15 5.1LIMITS. 15 5.2INFORMATION TO BE SUBMITTED WITH THE TENDER.15 6.DATA AND INFORMATION TO BE SUBMITTED.16 6.1DATA AND INFORMATION TO BE SUBMITTED WITH THE TENDER16 6.2DATA AND INFORMATION TO BE SUBMITTED AFTER AWARD OF ORDER 16 7.FABRICATION17 8.SHOP INSPECTION AND TESTING18 8.1GENERAL 18 8.2INSPECTION.18 8.3TESTING. 18 9.PROVISIONS FOR TRANSPORT20 9.1CLEANING 20 9.2PRESERVATION.20 9.3TRANSPORTING20 10.INSTALLATION, OPERATION AND MAINTENANCEMANUALS21 11.INSTALLATION22 11.1GENERAL 22 11.2INSTALLATIONPROCEDUREFORRDCsTRANSPORTEDWITHOUT ROTOR 22 11.3INSTALLATION PROCEDURE FOR RDCs TRANSPORTED WITH ROTOR 24 12.SITE TESTING26 12.112-HOUR TEST RUN26 12.2HYDROSTATIC TEST.26 12.38-HOUR TEST RUN26 13.MAINTENANCE28 13.1GENERAL 28 13.2MECHANICAL SEAL FAILURE.28 13.3REPAIR OF SHAFT SEALING DEVICES.29 14.REFERENCES31 APPENDICES APPENDIX 1RDC WITH SHAFT IN TWO SECTIONS 34 DEP 31.22.01.31-Gen. December 1995 Page 3 APPENDIX 2RDC WITH SINGLE SHAFT35 APPENDIX 3SHAFT SEALING AND TOP BEARING.36 DEP 31.22.01.31-Gen. December 1995 Page 4 1.INTRODUCTION 1.1SCOPE This DEP specifies requirements and gives recommendations for rotating disc contactors (RDCs). Sections 3 through 10 cover the design, fabrication, shop inspection and testing and delivery. Sections 11 through 13 cover the installation, site testing and maintenance. This DEP is a revision and combination of two previous publications, DEP 31.22.01.31-Gen. and DEP 61.22.01.31-Gen., both dated October 1982. DEP 61.22.01.31-Gen. is herewith withdrawn. Requirements for RDCs made of glass-fibre reinforced epoxy are excluded from the scope of this DEP. 1.2DISTRIBUTION, INTENDED USE AND REGULATORY CONSIDERATIONS Unless otherwise authorised by SIOP and SIEP, the distribution of this DEP is confined to companies forming part of the Royal Dutch/Shell Group or managed by a Group company, and to Contractors and Manufacturers/Suppliers nominated by them (i.e. the distribution code is “F“, as described in DEP 00.00.05.05-Gen.). This DEP is intended for use in oil refineries, chemical plants, gas plants, oil and gas production facilities, and supply/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, environmental, economic and legal aspects. In all cases the Contractor shall inform the Principal of any deviation from the requirements of this DEP 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 DEP as closely as possible. 1.3DEFINITIONS 1.3.1General Definitions The Contractor is the party which carries out all or part of the design, engineering, procurement, construction and 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. 1.3.2Specific definitions The drive is the prime mover. The driving unit consists of the prime mover and the speed reducer. The requisition is the vehicle used to exchange information prior to order placement, using the appropriate data/requisition sheets (e.g. DEP 31.22.01.93-Gen. for rotating disc contactors, DEP 33.66.05.93-Gen. for electric motors). DEP 31.22.01.31-Gen. December 1995 Page 5 1.4CROSS-REFERENCES Where cross-references to other parts of this DEP are made, the referenced section number is shown in brackets. Other documents referenced by this DEP are listed in (14). DEP 31.22.01.31-Gen. December 1995 Page 6 2.GENERAL DESCRIPTION OF AN RDC An RDC consists of a vertical cylindrical vessel, divided by a series of stator rings into a number of equally spaced compartments. A rotor disc supported by a shaft is centred in each compartment (see Appendices 1 and 2). The diameter of the discs is smaller than the inside diameter of the stator rings, thus permitting assembly and withdrawal of the rotor for installation and maintenance. The feed inlets at the top and bottom are placed tangential to the direction of rotation. The settling zones at the top and bottom are separated from the contacting zone by means of a wide-mesh grid. The liquid with the higher density enters the RDC at the top. The liquid with the lower density enters at the bottom and flows upwards, counter-currently to the descending liquid of higher density. Rotation of the rotor will cause one of the liquids to become dispersed in the other. Variation of the rotor speed provides a simple means of controlling the droplet size of the dispersed phase and thereby the efficiency of the RDC. The rotor is driven at the top by either a variable-speed electric motor or an electric motor with a variable-speed transmission. The rotor shaft is suspended from a spherical roller thrust bearing at the top and centred by a bottom sleeve bearing and, depending on the size of the RDC, by one or more intermediate sleeve bearings. If intermediate bearings are used, the rotor shaft consists of two or more parts, connected to each other by a rigid coupling. The top bearing is oil-bath lubricated, while the bottom bearing and the intermediate bearing, if applicable, are lubricated by the product in the RDC. During rotation of the rotor, the shaft is sealed by a mechanical seal. Above the mechanical seal two auxiliary lip seals are installed to prevent excessive losses of product in the event of a mechanical seal failure (see Appendix 3). A vent/drain line is connected to the chamber between the mechanical seal and auxiliary lip seals to carry away any leakage of product to a safe location. The mechanical seal housing shall be continuously flushed to prevent fouling, to remove any gas accumulation around the seal faces and for cooling purposes. Below the mechanical seal a stationary seal and inflatable seal are installed, which will be used in the event of a mechanical seal failure, but only when the rotor is stationary. Following a mechanical seal failure, the inflatable seal is pressurised with nitrogen from an external supply. In this way the contents of the RDC will be isolated from the damaged seal. The stationary sealing is obtained by lowering the rotor shaft onto a stationary sealing flange containing an O-ring. The intent of this design arrangement is to continue operation with the rotor in the stationary position and to carry out mechanical seal repairs while the vessel remains under operating pressure. DEP 31.22.01.31-Gen. December 1995 Page 7 3.BASIC DESIGN REQUIREMENTS The RDC shall meet the requirements specified in the requisition and shall be capable of continuous operation (i.e. uninterrupted operation for a period of at least 16 000 hours at the specified operating conditions) without undue noise and vibration. It shall incorporate all the design features indicated on Standard Drawing S 23.101 and the following standard drawings mentioned therein: S 23.104, S 23.105 and S 23.106. The Manufacturer shall be responsible for the detailed design, including: -The required motor power. -The correct sizing of the vessel wall thickness. -The correct sizing of the vessel accessories. -The correct sizing and construction of the shaft and disc. -The correct sizing of speed transmission, couplings, bearings and shaft seals. If constructional deviations could affect the Principal's installation instructions as mentioned in Section 11 of this DEP, the Manufacturer shall supply additional instructions. For material selection of the gaskets, see also report MF 94-0960. DEP 31.22.01.31-Gen. December 1995 Page 8 4.DESIGN AND ENGINEERING 4.1VESSEL The design of the vessel shall be in accordance with the applicable pressure vessel code as stated by the Principal, which shall be: BS 5500, as amended and supplemented by DEP 31.22.10.32-Gen., or ASME VIII, as amended and supplemented by DEP 31.22.20.31-Gen. 4.1.1Skirt The RDC shall be provided with a cylindrical skirt. Anchor bolts shall straddle the centre lines of the RDC. For details of the skirt and base, reference is made to S 20.001 and S 20.004, respectively. 4.1.2Nozzles The feed inlet nozzles should be placed either tangential to the direction of rotation of the rotor, or normal, with a tangential tube to the wall, see S 23.101. For the tangential nozzles, the distance from the centre line of the inlet nozzles to the vessel centre line shall be as large as permitted by code requiremen