Shell boilers – part 7: Requirements for Firing systems for liquid and Gaseous fuels

رقم المستند: NL prEN 12953 7 : 2002
القطاع: Mechanical Systems and Components for General Use
TC: NL TC IRI
ICS: 91.100.01
1.1 Firing systems These requirements apply to oil and gas firing systems of steam and hot water generators. For multifuel firing systems using separate or combined these requirements shell apply to oil and/or gas firing part involved . Where several fuels are bumt simultananeously, improved safety measures may be necessary, especially in respect to limitation of heat input into the firing system and proper air supply to the individual fuels. For oil and gas firing system with one bumer per combustion chamber and a firing rate <15 MW these requirements are deemed to have been constructed in accordance with EN 276 or EN 676 and has been type-approved. In addition, however, the requirements of 4.3.3 shall be met unless they apply to the bumer itself. The requirements of 6.2, 6.5.3, 6.6.4, 6.7, 7 and 8 shall e met unless they are covered by the bumer type approval. In any case, bumers to EN 676 shall be equipped with a gas pressure monitor for monitoring the highest gas pressure. 1.2 Fuels These requirements cover the use of liquid and gaseous fuels as classified in the appropriate standards. Liquid fuel include light fuel oils, and heavy fuel oils which need preheating for proper atomization. For improvement of atomization, emulsions of heavy fuel oil with water may be used with appropriate precautions. Gaseous fuels of standardized quality are to be differentiated mainly by their relative density. Light gases with relative density below 1.3 are e.g natural gas according to ISO 6976, coke-oven gas, blast-fumace gas. Heavy gases with relative densities exceeding 1.3 are e.g liquefied petroleum gases, the main components of which’re propane and butan. Fuels deviating from standardized commercially available types may require extra safety measures . For black liquor such extra safety measures are given in annex B. 1.3 Operation The requirements for operational in clauses 4 to 8 apply to steam and hot water generators with permanent supervision by properly trained personal familiar with the special conditions of the firing system and the type of fuel being fired annex A comprises additional requirements for operational equipment for firing systems without permanent supervision.