oucpuc)oraif rate (between 0.7 and around 1 5). The nominal powef ranges from 20 kW ro 11000 kW and intefmediace power burnef sizes can be calculated in a few minuces. Mofeovef, it is a good dual fuel burner, being able ro be supplied with narnral gas, manufaccured gas, LPGs, biogas, bur also, with a slight change in supply devices, with oil or even wich ground coal. It may also be used co bum differenc wasce prod ucts as ground electfic insulacors, sawdusc, . . . Flue Gases Gas 2-2. The "Ceramic Self Recuperacive Jet Burner" The emergence of chermomechanical ceramics, mainly silicon carbide, associated with ehe design of ehe opposice swirls applied co a self-recuperacive burner, resulced in ehe developmenc of chis burner. As irs name implies, chis burner is made ofceramic and is a "jec" burner. Primicively designed co operare in recirculacion radianc cubes, ic is available in several power oucpucs. Depicted in figure 2, irs combuscion chamber, drilled wich several rows ofcangencial air injeccion holes co Cfeace a greac nırbulence, is made ofsilicon cacbide. The oucer parcicion ofehe air supply chamber is made ofrefraccory sceel and bears fins on boch sides, chus realizing an exchanger. The flue gases flow ouc chrough ehe oucer pare of ic, preheacing ehe combuscion air flowing in ehe inner pare. The 30 co 45 kW cype, mounced on a recirculacion radianc cube (ehe recirculacion cube is also made of silicon carbide), has a combuscion efficiency of %75 for a furnace cemperacure up co 1 100° C. 96 such radianc cubes, wich 3 5 kW burners, lıave been mounced on a 280 c/day magnecic sceel sheec heacing furnace. This fetroficcing increased ehe produccion by 20 %. Aside effecc due co irs design (ehe several rows of air injeccion lıoles induce a scaged combuscion) is chac ic is a relacively low N0, burner: ehe N0, emissions afe afound 500 mg/m3 ofehe flue gases, co be compafe<l wich ehe 750 mg Of mofe wiclı classical ones. 2-3. The "Low NO, Burner" DOGAL GAZ DERGİSİ SAYI. 29 95 Wich ehe environmencal procection problem emerging these days ,arose the problem ofN0x emissions, which concribme co the acid rain effect. In France, the regulacions felaced ro N0 x emissions concern burners over 30 MW, duıt is co say mainly burnefs p,ounced on industrial boilers, the design ofwhich is particular. Gaz de France Research Cencer, in cooperation wich a French manufacmrer, Pıllard, developped such a low N0xburner. le has been shown ebat N0, emissions are Flg.2 connecced, among ochef chings, wich ehe cemperacufe ]eve! of ehe flame. Thus, cooling ehe flame will decfease ehe nicrogen oxide emissions. Among differenc solmions, ehe choice made by Gaz de France and ehe manufacrnfef, was co scage ehe injeccion of gas. Due co ehe design of boilef burnefs, scaging ehe aif injeccion would imply an incfease in ehe scacing ehe aif injeccion woulcl imply an incfease in ehe size ofehe burner, chus a moclificacion ofehe boiler. On ehe concrafy, scaging ehe gas injeccion needs nochange in ehescruccure ofeheburner, as excra gas injeccors are mounced on bene pipes ser in ehe cencral porc ofehe block. The resulcs of ehe cescs perfofmecl in GDF laboracories wefe usecl co develop cwo burnefs mouncecl on a 25 MW boilef in Roissy-Charles de Gaulle Aifpoft. N0x amouncs have been measured during ehe differenc sceps of ehe recroficcing: -burnef suppliecl wich oil: 300 mg/ml -burnef supplied wich gas - classical: 150 mg/ ml -burner suppliecl wich gas - low N0x: 60 co 90 mg/ml The modificacion of ehe burnef did noc impa impair ehe efficiency of ehe boiler Of ehe vefsacilicy of ehe burner. 2-4. Regeneracive Burners Regeneracive burners afe a vefy accraccive solucion co recovef energy in high cemperacure furnaces (glass melring, heacing ofmecals fof an example), as chey may save enefgy up co 65 % when compafe<l to cradicional burnefs in ehe
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