BS-EN-12953-12-2003.pdf

BRITISH STANDARD BS EN 12953-12:2003 Shell boilers Part 12: Requirements for grate firing systems for solid fuels for the boiler The European Standard EN 12953-12:2003 has the status of a British Standard ICS 27.060.30; 27.100 ? BS EN 12953-12:2003 This British Standard, was published under the authority of the Standards Policy and Strategy Committee on 14 October 2003 © BSI 14 October 2003 ISBN 0 580 42758 7 National foreword This British Standard is the official English language version of EN 12953-12:2003. When reference to this part of the European Standard has been published in the Official Journal of the European Communities (OJ), compliance with it will confer a presumption of conformity with the essential safety requirements of the Pressure Equipment Directive covered by this part of the standard. The UK participation in its preparation was entrusted to Technical Committee PVE/16, Shell boilers, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 18, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. DateComments EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM EN 12953-12 September 2003 ICS 27.060.30; 27.100 English version Shell boilers - Part 12: Requirements for grate firing systems for solid fuels for the boiler Chaudières à tubes de fumée - Partie 12: Exigences pour les équipements de chauffe à grille pour combustibles solides de la chaudière Großwasserraumkessel - Teil 12: Anforderungen an Rostfeuerungsanlagen für feste Brennstoffe für den Kessel This European Standard was approved by CEN on 12 June 2003. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels © 2003 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12953-12:2003 E EN 12953-12:2003 (E) 2 ContentsPage Foreword3 1Scope 4 1.1Firing systems4 1.2Fuels4 1.3Operational equipment4 2Normative references 4 3Terms and definitions5 4Fuel bunkers with conveying plant6 4.1General6 4.2Conveying plant.7 4.3Fuel bunkers.7 4.4Fuel bins .8 5Fuel treatment 8 5.1General8 5.2Size reduction of the fuel8 5.3Drying of the fuel8 6Fuel feeding9 7Explosion prevention measures.9 8Equipment for combustion air supply and flue gas discharge.10 8.1Air supply10 8.2Combustion air/fuel ratio 10 8.3Flue gas discharge 10 9Firing system11 9.1General11 9.2Control and monitoring.11 9.3Electrical equipment11 9.4Safety precautions.11 9.4.1General11 9.4.2Purging of the flue gas passes12 9.4.3Lighting-up .12 9.4.4Start-up .12 9.4.5Shutting down13 9.5Common stack for several firing systems 13 10Ash handling and extraction.13 11Operation and maintenance14 11.1General14 11.2Operating instructions 14 Annex A (informative) Operational requirements for permanently supervised firing systems for solid fuels on grate firing systems15 Annex ZA (informative) Relationship between this European Standard and the Essential Requirements of EU Directive 97/23/EC .17 Bibliography18 EN 12953-12:2003 (E) 3 Foreword This document EN 12953-12:2003 has been prepared by Technical Committee CEN/TC 269 “Shell and water-tube boilers”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by March 2004, and conflicting national standards shall be withdrawn at the latest by March 2004. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s) (Pressure Equipment Directive 97/23/EC) 1. For relationship with EU Directive(s), see informative annex ZA, which is an integral part of this document. The European Standard EN 12953 concerning shell boilers consists of the following Parts: ? Part 1:General ? Part 2:Materials for pressure parts of boilers and accessories ? Part 3:Design and calculation for pressure parts ? Part 4:Workmanship and construction of pressure parts of the boiler ? Part 5:Inspection during construction, documentation and marking of pressure parts of the boiler ? Part 6:Requirements for equipment for the boiler ? Part 7:Requirements for firing systems for liquid and gaseous fuels for the boilers ? Part 8:Requirements for safeguards against excessive pressure ? Part 9:Requirements for limiting devices of the boiler and accessories ? Part 10: Requirements for feedwater and boiler water quality ? Part 11: Acceptance tests ? Part 12: Requirements for grate firing systems for solid fuels for the boiler ? Part 13: Operating instructions CR 12953 Part 14: Guideline for the involvement of an inspection body independent of the manufacturer (TR) Although these Parts may be obtained separately, it should be recognized that the Parts are interdependent. As such, the design and manufacture of shell boilers requires the application of more than one Part in order for the requirements of the European Standard to be satisfactorily fulfilled. The annex A of this European Standard is informative. This document includes a Bibliography. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and the United Kingdom. EN 12953-12:2003 (E) 4 1 Scope 1.1 Firing systems This part of this European Standard specifies the requirements for internal or external grate firing systems commencing at the fuel bunkers and ending at the ash extraction plant. For combination of various firing systems, the individual requirements of each system also apply. If several fuels are burnt simultaneously or if a fuel quality varies considerably (e.g. moisture content), additional safety measures can be necessary, especially with respect to limitation of the fuel flow into the firing system and ensuring proper air supply to the individual fuels. 1.2 Fuels The solid fuels covered are: ? all coal qualities, e.g. lignite or brown coal, sub-bituminous or hard brown coal, bituminous coal or hard coal, pitch coal, anthracite, coke, coal culm, coal sludge; ? other fossil solid fuels (e.g. petrol coke peat, oil shale); ? biomass solid fuels (e.g. wood, wood wastes bark, energy plants miscanthus, harvest wastes straw); ? municipal waste solid fuels (e.g. garbage, sewage sludge, refuse derived fuels RDF); ? industrial waste solid fuels (e.g. petrol coke, soot, tyres, paper wastes, coated wood chips, spent wood, animal product wastes). Fuel blends from two or more of these groups (see 4.1.7), or fuels of unconventional or unknown quality can require special safety measures which can be proved either by practical experience gained from comparable fuels, or by suitable tests, e.g. in accordance with EN 26184-1. Such measures should be documented by the manufacturer. Fuels on which the design is based should be specified in the operating instructions (see 11.2). This should include the fuel data for 100 % input of the basic fuel and the data for any supplementary fuels together with their maximum thermal input percentage. 1.3 Operational equipment The requirements for operational equipment in clauses 4 to 10 apply to steam boilers and hot water generators with permanent supervision by properly trained personnel familiar with the special conditions of the firing systems and the type of fuel. Annex A contains the operational requirements for permanent supervision. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text, and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments). EN 12952-8:2002, Water-tube boilers and auxiliary installations Part 8: Requirements for firing systems for liquid and gaseous fuels for the boiler. EN 12952-9:2002, Water-tube boilers and auxiliary installations Part 9: Requirements for firing systems for pulverized solid fuels for the boiler. EN 12953-7, Shell boilers Part 7: Requirements for firing systems for liquid and gaseous fuels for the boiler. EN 12953-12:2003 (E) 5 EN 26184-1, Explosion protection systems Part 1: Determination of explosion indices of combustible dusts in air (ISO 6184-1:1985). prEN 50156-1, Electrical equipment for furnaces and ancillary equipment Part 1: Requirements for application design and installation. 3 Terms and definitions For the purposes of this European Standard, the following terms and definitions apply. 3.1 back-up firing system separate firing system to maintain safe ignition and stable combustion. The lighting-up equipment can be used for this purpose 3.2 basic fire layer of glowing fuel, fire bed or flame of the fed fuel. The basic fire can also perform the duty of the lighting-up equipment, or the back-up firing system (mostly air) 3.3 carrier gas transport medium for pneumatic conveying 3.4 combustion air total air supplied to the firing system for combustion 3.5 firing systems can be distinguished in accordance with the type and structure of the fuel, the feeding procedure and the process of combustion. Fuel and air can be introduced in the combustion chamber in different ways to establish and maintain proper ignition and stable combustion. Combustion of the fuel is performed on grates 3.6 fuel bin silo dust-tight container for temporary storage of combustible solids in the boiler room 3.7 fuel bunker open storage of solid fuel 3.8 fuel feeding system device to transport fuel into the combustion chamber NOTEThis can be effected directly by feeders through ports in the furnace walls, by means of chutes or through the bottom grate 3.9 fuel handling plant installation for conveying, mixing and distributing solid fuels to the individual fuel bunkers or fuel bins 3.10 grate firing system fuel is burnt in a layer supported by a system of firebars which may have a cooling system NOTEThe firebars should be so spaced as to admit the undergrate combustion air supply in proper distribution. Other means of admitting and distributing the combustion air supply can be provided. EN 12953-12:2003 (E) 6 3.11 indicator measuring instrument which indicates a variable value (e.g. pressure, temperature, flow, level). It can be equipped with an annunciator 3.12 lighting-up equipment facility to achieve safe ignition of the feed fuel 3.13 limiter transducer, which, on reaching a fixed limit value (e.g. pressure, temperature, flow, level) is used to interrupt and lockout the energy supply and It requires manual unlocking before restart 3.14 lockout interruption of the energy supply. Manual unlocking is required before restart 3.15 master fuel trip device located at a safe place for rapid automatic shutoff of all fuel supplies to the grate and electrical igniters in the event of danger 3.16 maximum continuous rating (MCR) allowable heat output steam boiler or hot water heat output that can be generated during continuous operation and at which the steam or hot water generator may be operated, taking the specified steam condition or hot water condition (water mass flow times the difference between outlet and inlet enthalpy) into consideration 3.17 monitor transducer that senses the reaching of a fixed limit value and initiates an alarm and/or a shut-down. The output signal only reverses if the causing value has changed at a defined range 3.18 purging of the flue gas passes flow of air through combustion chamber, flue gas passes, and associated ducts including flue-gas treatment systems, which effectively removes any gaseous combustibles and replace them with air 3.19 start-up condition the plant can be started ? cold (temperature of ceramic lining is at ambient value); ? hot (temperature of ceramic lining is above the minimum ignition temperature of the basic fuel); or ? warm (temperature of ceramic lining in between the ambient and minimum ignition temperature) 4 Fuel bunkers with conveying plant 4.1 General 4.1.1All facilities shall be designed so as to withstand mechanical and thermal stresses. Fuel shall not be heated to an unacceptable level. Sites where fuel may accumulate shall be avoided. 4.1.2Conveyance, temporary storage, and extraction of the fuel shall be arranged such that sufficient flow of the fuel and additives is ensured. EN