|Conference||American Flame Research Committee, Salt Lake City, Utah, September 5-7, 2012|
|Creator||Bussman, W. R.; Baukal, C. E.|
|Spatial Coverage||presented at Salt Lake City, Utah|
|Abstract||Before the 1940s, it was a common practice in industry to vent hydrocarbon process streams to the atmosphere, unburned. Typical vent gases are flammable and may contain harmful chemicals. Eventually, regulations required that these vented streams be burned, so flares became both a safety and environmental control device. Since the inception of flaring, technology advancements have made some significant progress towards making flaring more environmentally-friendly. These include: (1) reducing the fuel consumption of flare pilots, (2) implementing purge reduction devices to reduce the amount of supplemental fuel gas burned (3) using steam more efficiently to achieve smokeless flaring and (4) installing flare gas recovery systems to reduce the amount of gas flared. The purpose of this paper is to discuss how these methods conserve energy and reduce emissions from flares.|
|Rights||This material may be protected by copyright. Permission required for use in any form. For further information please contact the American Flame Research Committee.|
Environmentally-Friendly Flaring Page 1 of 12 2012 American Flame Research Committee (Salt Lake City, UT) Copyright 2012 John Zink Co. LLC Environmentally-Friendly Flaring W.R. Bussman and C.E. Baukal John Zink Company LLC (Tulsa, Oklahoma) Abstract Before the 1940s, it was a common practice in industry to vent hydrocarbon process streams to the atmosphere, unburned. Typical vent gases are flammable and may contain harmful chemicals. Eventually, regulations required that these vented streams be burned, so flares became both a safety and environmental control device. Since the inception of flaring, technology advancements have made some significant progress towards making flaring more environmentally-friendly. These include: (1) reducing the fuel consumption of flare pilots, (2) implementing purge reduction devices to reduce the amount of supplemental fuel gas burned (3) using steam more efficiently to achieve smokeless flaring and (4) installing flare gas recovery systems to reduce the amount of gas flared. The purpose of this paper is to discuss how these methods conserve energy and reduce emissions from flares. Introduction During the oil boom in the early 1900s, it was a common practice to vent gases, unburned, into the atmosphere in the course of oil and gas production operation; this practice was extremely unsafe and lead to many industrial fires and explosions (see Figure 1). In the 1940s, the custom of unburned venting began to change when industry became more environmentally aware and concerned about safety. Eventually, regulations required that vented streams be burned, so flares became both a safety  and environmental control  device. Figure 1. Oil tank fire in Cygnet, Ohio (1912) . Today, flaring is still the primary method used throughout the world to safely dispose of the flammable waste gases generated at facilities. There are many types of flares [4,5] which are commonly found in oil refineries, petrochemical/chemical plants, landfills, near oil and gas Environme 2012 Amer wells, na flare head flare burn most imp employee the entire F Wast may be e from ups collected Vapors m gases tha gases nee equipmen Large because f about 12 about 16 To th generatin complete recycling The f The unste the waste composit produce a entally-Friendly rican Flame Re atural gas pla ders, and rou ning a waste portant safety es and the op e facility is j Figure 2. Wa te gas routed excess gas th set condition d from the to may come fro at are stored ed to be flare nt from over e amounts of flare gas flow million tons million tons he casual obs ng pollution. ely eliminate g the waste g flow rate and eady flow (s e gases elsew tion makes it more cons y Flaring esearch Comm ants and load uted to the fl e gas generat y systems in perating faci eopardized [ aste gas flare d to a flare ca hat is supplie ns in the plan ps of storage om the flamm at a facility ed during an r-pressuring. f waste gase w rates are n s of gas in 19 s of gas were server, flarin An obvious e flaring alto gas (e.g., ) d compositio see Figure 3) where in the t difficult to istent compo mittee (Salt Lak ding termina lare system w ted in a proc n a facility [1 ility . If a 7]. ed in a proce an come from ed commerci nt or during m e tanks while mable gas ge need to be fl n emergency . es are flared e not typically 974 . Ba e flared in th ng may seem s question is gether? Alth ), it is not alw on of the was ) and variabl plant where sell, unless osition. The ke City, UT) als. The wast where they a cess plant. F 1]. They are flare system ess plant (wit m several dif ially to custo maintenance e they are be enerated und flared during , such as a p each year wo monitored. ased on the e he U.S. in 19 m like faciliti why not use hough some ways econom ste gases goi le compositi the energy d some type o waste gases C te gases are c are burned. F Flares are con designed to m is not oper th permissio fferent sourc omers . A e and installa eing filled m derground at g a productio power outage orldwide. Th Estimates sh extrapolated 980 . es are unnec e this energy facilities try mically justi ing to the fla ion (see Tabl demand is n of purificatio s may have a Copyright 2012 collected in Figure 2 sho nsidered to b protect the p rating proper on from Drea ces . For e At times, the g ation of equi may be routed t landfill site on shutdown e, to prevent he exact amo how that the data, estima cessarily was y somewhere y to minimiz ified or easil are are often le 1) make it normally stea on system is fairly low h Page 2 2 John Zink Co pipes, called ows an elevat be one of the public, the s rly, the safet amstime). example, the gas may com ipment. Vap d to a flare. es. Sometime . Occasional t tanks and ount is unce e U.S. flared ates show tha sting energy e else, or jus e flaring by ly done. n highly varia t difficult to ady. The var added to heating value of 12 o. LLC dt ed e ite ty of e gas me ors es lly, rtain at y and st able. use riable e, Environme 2012 Amer which me value. Th and are n some tim Figure 3. Since towards m consump efficient After was creat hoisting a of the fla or reliabl entally-Friendly rican Flame Re eans that equ he waste gas not easily rep me during sta . Example month per Tab e the inceptio making flari ption of pilot manner to a r regulations ted. Several burning ra are, or shooti le. In 1948, t y Flaring esearch Comm uipment such es may be o processed to artup until th of waste gas riod. ble 1. Examp on of flaring ing more env ts, (2) implem achieve smok Redu for flaring w unorthodox ag soaked in ing a signal f the John Zin mittee (Salt Lak h as burners ff-spec prod produce onhe product is s flows to a f ple of waste g, technology vironmentall menting purg keless flaring ucing Flare waste gases methods we oil to the top flare over th nk Company ke City, UT) s must be pro duct that is b -spec produc within speci flare in a typ gas compos y advanceme ly-friendly. T ge reduction g and (4) ins Pilot Fuel C were implem ere initially u p of the flare he top of the developed t C operly design eing flared b ct . Off-s ification. pical refinery sitions at a ty ents have ma These includ n devices, (3 stalling flare Consumptio mented, a ne used to ignit e, shooting a flare . T the first pilot Copyright 2012 ned for the l because they spec flaring y over appro ypical plant. ade some sig de: (1) reduc ) using steam e gas recover on eed for flare te flares; for flaming arr These method t used to ign Page 3 2 John Zink Co low heating y cannot be s may occur f oximately an gnificant step cing the fuel m in a more ry units. ignition syst example, row over the ds were not nite and of 12 o. LLC sold for n 8 ps tems e top safe Environme 2012 Amer continual marked t Figure 4. The p out of the safety fea cannot ac typically Figure 5. more pilo gases tha Flare (9.9 m3/h demande offer pilo continued operate in entally-Friendly rican Flame Re lly burn vent he beginning . The first p (1948). primary purp e flare tip un ature of a fla chieve its pri burn contin . Multiple pi ots are used at are more d pilots used hr) of fuel ga ed pilots with ots with a fue d demand fo n the range o y Flaring esearch Comm ted waste ga g of the flare pilot used to pose of the fl nder all opera are system b imary object nuously and a ilots are used on flare tips difficult to bu Figure 5. from the late as. However h lower fuel el consumpt or lower fuel of 50 ft3/hr ( mittee (Salt Lak ases from a f e industry. o ignite and c flare pilot is t ating conditi ecause if the tive: the safe are positione d for redunda with larger urn, such as Flare tip wit e 1940s to th , in the mid consumptio ion of about l consumptio 1.4 m3/hr). ke City, UT) flare (see Fig continually b to rapidly an ions . Pi e pilots fail t e and effecti ed around th ancy to ensu diameters o gas streams th pilots arou he mid 1980 1980s, when n . In ab t 150 ft3/hr (4 on, flare man C gure 4). The burn vented w nd reliably ig ilots are con to light the w ve disposal he perimeter ure ignition o r on flares th with high in und the perim 0s were desig n gas prices bout 1984, fl 4.2 m3/hr) a nufacturers t Copyright 2012 supply of pi waste gases gnite the ven sidered the m waste gas stre of gases and of flare outl of the vent g hat are desig nert contents meter. gned to burn were high, i lare manufac s shown in F today can off Page 4 2 John Zink Co ilots to indus from a flare nt gases flow most importa eam, the flar d liquids. Pil lets as shown gases. Usuall gned to burn s. n about 350 f ndustry ctures began Figure 6. Wi ffer pilots tha of 12 o. LLC stry e wing ant re ots n in ly, ft3/hr n to ith a at Environme 2012 Amer Figure 6. The m earliest p benefit in there are flares wit gas on a fuel cost fuel cons Table 2. When infiltrate can lead (see Figu entally-Friendly rican Flame Re . (a) High h pilot deve pilot. most recently pilots; a subs nto perspecti over 1,000 f th each flare continuous b and CO2 em sumption usi Estimation pilots in Te n the flow of into the flar to flame bur ure 7) . y Flaring esearch Comm heat release eloped in the y developed stantial savin ive, accordin flares in Tex e having an a basis at a fue missions for e ing today's f ns comparin exas. Impl f gas through re tip and mi rnback, whic mittee (Salt Lak flare pilot de e mid 1980s; d pilots only r ngs in fuel co ng the Texas xas . For average of tw el cost of $3 each pilot ar flare pilots c ng fuel cons lementing P h a flare stac igrate into th ch in turn co ke City, UT) eveloped in ; approximat require abou ost and more s Commissio r estimate pu wo pilots. Al per million re shown in T ompared to sumption, fu Purge Reduc ck reduces to he flare syste uld initiate a C the late 1940 tely 20% the ut 20% of th e environmen on on Enviro urposes, assu lso assume t Btu. The est Table 2. Not the earliest d uel cost and ction Device o very low o em. Infiltrati destructive Copyright 2012 0s, (b) energ e heat release e fuel consu ntally-friend onmental Qu ume that Tex that each pilo timated fuel tice the dram designs. d CO2 emis es or no flow co on of air into e detonation Page 5 2 John Zink Co gy efficient f e of the 1950 umption of th dly. To put th uality (TCEQ xas has 1,000 ot burns natu l consumptio matic reducti ssions from onditions, air o a flare syst in the system of 12 o. LLC flare 0s he his Q), 0 ural on, ion in flare r can tem m Environme 2012 Amer Figu The m flow a sm flare syst composit system fo Addin purge ga tip moun common The m seals prev driving a location A illustratio entally-Friendly rican Flame Re re 7. Damag most effectiv mall amount tem . Th tion of the pu ollowing a v ng a purge r s required. N nting flange t ly used in th molecular se vent air infil air deep into (lighter th on in Figure y Flaring esearch Comm ged liquid se ve method fo of oxygen-f he required p urge gas, an vent or relief reduction dev Normally, pu to minimize he flare indus eal was paten ltration in tw the stack an an air purge 8. mittee (Salt Lak eal and ruptu or preventing free hydrocar purge gas flo d the compo f event. vice to a flar urge reductio the air exclu stry: molecu nted by Reed wo ways: by nd by produc gas) or B (h Figure 8 ke City, UT) ure disk caus g air infiltrat rbon or inert w depends o osition of any re system can on devices ar usive zone. T ular seal and d of the John preventing t cing a gas ba heavier than . Molecular C sed by a deto tion into a fl t gas, called on the size a y waste gas n substantia re installed i Two types o velocity sea n Zink Comp the action of arrier to the a air purge ga seal. Copyright 2012 onation in th lare system i purge or sw and design of that could b ally reduce th immediately f purge redu al. pany in 1965 f the ambient air entering t as) as shown Page 6 2 John Zink Co he flare stack is to continu weep gas, int f the flare, th e present in he amount of y below the f uction device 5 . Mole t wind from the stack at n in the of 12 o. LLC k. ously to the he the f flare es are ecular Environme 2012 Amer Veloc the stack the veloc ingressio Purge than for f flow rate Table 2. When typically typically was that Figure 12 in the ear opening that refin public do pollution entally-Friendly rican Flame Re city seals mi k as illustrate city seal brea on. e gas flow ra flares withou es for a 36 in Comparing without a p n flaring firs consisted of referred to a they produc 2). At the tim rly 1950s, sm statement at nery flares at oes not think n.'" y Flaring esearch Comm inimize air in ed in Figure 9 aks the flow ates for flare ut purge redu n. (91 cm) dia g natural gas purge reduct st became co f a length of as pipe flare ed large clou me, there we moking flare the America ttract a great k they are be mittee (Salt Lak ngression by 9. As ambien attachment a Figure 9 es with molec uction devic ameter flare s purge rates tion device. Using Steam ommonplace f open-ended s (see Figure uds of black ere no restric es became un an Petroleum t deal of atten autiful. …. P ke City, UT) y using a con nt air flows and provides 9. Velocity s cular seals a ces. Table 2 s tip with and s for a 36 in. m More Eff , most hydro d pipe suppo e 11). One o k smoke whe ctions on how nacceptable i m Institute (A ntion; unfort People look C ne-shaped ba down the in s a velocity seal. and velocity shows a com d without a p (91 cm) dia ficiently ocarbons we rted by a str of the major p en heavy hyd w flares were in many urb API) session tunately, it i at the black Copyright 2012 affle to impe side walls of barrier to fu seals are sub mparison of n purge reduct ameter flare t ere burned in ructure; these problems wi drocarbons w e to be opera ban areas. In n on flares w s not favorab smoke and Page 7 2 John Zink Co ede air flow f the flare st urther air bstantially le natural gas p tion device. tip with and n flares that e flares are ith pipe flare were burned ated. Howev 1952, the was "We all k ble. The gen say: ‘That is of 12 o. LLC into tack, ess purge es (see ver, know neral s air Environme 2012 Amer There flare desi John Zin the perim entally-Friendly rican Flame Re Figure e were many ign to succes k Company meter of the f y Flaring esearch Comm e 10. One of y attempts to ssfully suppr in 1957  flare tip (see mittee (Salt Lak f the first pip Figure 11 o redesign th ress the form ]. This flare e Figure 12) ke City, UT) pe flares used 1. Smoking f e simple pip mation of sm was designe and is referr C d in the proc flare. pe flare to su moke on a pip ed with steam red to as a ste Copyright 2012 cess industrie uppress the sm pe flare was m nozzles po eam-assisted Page 8 2 John Zink Co es. moke. The f designed by ositioned aro d flare. of 12 o. LLC first y the ound Environme 2012 Amer The p core of th flare. The formation As re dramatic difficult t adequate central co is ideal fo entally-Friendly rican Flame Re purpose of th he waste gas e rapid mixin n. efinery and c ally, requirin to achieve sm ly penetrate ore of waste for smoke for y Flaring esearch Comm Figure 1 hese steam n s stream as il ng of the ste Figu chemical plan ng larger flar mokeless pe into the cen gas burning rmation. Als mittee (Salt Lak 12. An early nozzles is to llustrated in eam and air w ure 13. Mod nts grew larg re tips. As th erformance b ntral core of t g in an extrem so, the amou ke City, UT) y model steam entrain surro Figure 13 sh with the was ern steam-as ger over the hese tips inc because the s the waste ga mely reducin unt of steam r C m-assisted fl ounding amb howing a cur ste gas dram ssisted flare. years, flare reased in dia steam and ai as stream; th ng (oxygen d required to a Copyright 2012 flare. bient air and rrent model atically redu . relief capac ameter, it be r mixture co his condition deficient) atm achieve smo Page 9 2 John Zink Co d inject it into steam assist uces smoke cities increas ecame more ould not resulted in a mosphere w okeless burni of 12 o. LLC o the teded which ing Environme 2012 Amer could not problems assisted f This 14. A por momentu flare tip e especially core of th Toda plants [22 amount o manner c reduce st to reduce are differ air with t flares can back in th A fla to the fla the waste gas may reduce th recovered continuou noise and drawn to entally-Friendly rican Flame Re t be supplied s on large dia flare that wa new flare wa rtion of the s um of the hig exit. This de y on large di he waste gas ay, steam-ass 2]. An impo of air that is can dramatic team operatin e the steam r rent in desig the waste ga n achieve ab he early 195 re gas recov are system [6 e gases befor have a subst he amount of d flare gas a us flare oper d pollutant e the facility. y Flaring esearch Comm d because of ameter tips, as introduced as designed steam is deli gh pressure s esign provide iameter flare s stream. sisted flares rtant factor t mixed effect cally improve ng costs. Ov requirements n than the or s. Using the bout twice th 50s. Ins very unit (FG 6,24]. The FG re they are fl tantial heatin f purchased f s feedstock o ration, which missions ass Capturing w mittee (Salt Lak f perimeter a the John Zin d in the 1960 with tubes l ivered to stea steam pulls s ed a substant es, because t Figure 14. S are the predo that influenc tively with t e the smokel ver the years s for smokele riginal desig same amoun e smokeless stalling Flar GRU) is desig GRU is locat flared. There ng value and fuel. In certa or product in h subsequen sociated with waste gases m ke City, UT) area limitatio nk Company 0s . ocated insid am jets posit surrounding tial improve the steam an Steam-assiste ominant flar ces the smok the waste gas less perform , flare manu ess performa gns, they rely nt of steam, s capacity as re Gas Reco gned to capt ted upstream are many po d could be us ain applicati nstead of pur ntly reduces t h flaring. It a may reduce C ons at the tip y developed de the flare ti tioned at the air into the ement in smo nd air can eff ed flare. re type found keless perfor s. Using the mance of a ste ufactures hav ance (e.g., [2 y on the sam today's stat the steam-a overy Units ture waste ga m of the flare otential bene sed as a fuel ons, it may b rchased fuel the associate also reduces odor levels Copyright 2012 . In order to a more effic ip body as sh e inlet of eac tubes and ex okeless perfo fectively mix d in refinerie rmance of th steam in the eam-assisted ve made desi 23]). Althou me basic meth te-of-the-art assisted flare ases that wo e to capture efits of a FG in the plant be possible t l. The FGRU ed smoke, th s the negative in the plant. Page 10 2 John Zink Co eliminate th cient steamhown in Figu ch tube. The xhausts at th ormance, x with the ce es and chem hese flares is e most effici d flare and ign modifica ugh these flar hods for mix steam-assist es developed ould normally some or all o GRU. The fla , which wou to use the U reduces the hermal radiat e public atte Reduced fla 0 of 12 o. LLC hese ure he entral ical the ient ations res xing ted d y go of are uld e tion, ention aring Environme 2012 Amer also redu In refiner can provi shows an where fla Whil foreseeab environm methods implemen using ste These ha 1. Bello 11, N 2. F.A. Man 3. Max http: 4. T.A. 2, No 5. A. B Prog entally-Friendly rican Flame Re uces steam co ries with exc ide a means n example of aring has bee Fig e it is desira ble future. H mentally-frien used to imp nting purge am more eff ave been disc ovich J., Fran No. 4, pp. 47- Akeredolu an agement of E Shafer Colle //www.bgsu.e Brzustowski o. 3, pp. 129- Bader, C. Bauk gress, Vol. 10 y Flaring esearch Comm onsumption cess processto scrub the f a FGRU in en reduced b ure 15. FGR able to elimin However, new ndly by redu rove flaring reduction de ficiently to a cussed in thi nklin J. and Ba 54, 2006. nd J.A. Sonib Environmental ection, Bowlin edu/colleges/ i, Flaring in th 141, 1976. kal, and W. B 07, No. 7, pp. mittee (Salt Lak for steam-as -generated w e hydrogen su stalled at Fli by more than RU at FHR W Co nate flaring a w technologi ucing both fu performanc evices to red achieve smok s paper to sh R aukal C., The bare, A review l Quality, Vo ng Green Stat library/cac/m he Energy Ind Bussman, Sele 45-50, 2011. ke City, UT) ssisted flares waste gas bey ulfide (H2S) int Hills Res n 95% since West Plant in onclusions altogether, th ies continue uel consump e include: re duce the amo keless flaring how how the References e Last Line of w of the usefu l. 15, No. 6, p te University, ms/page44570 dustry, Progre ecting the Pro C s and can ex yond fuel ga ) before the w sources (FHR 1997 . n Corpus Ch hat is not lik to make flar ption and pol educing the f ount of suppl g and install ey make flar f Defense, Hy ulness of gas f pp. 574-583, 2 , .html#invento ess in Energy oper Flare Sys Copyright 2012 xtend the life as requireme waste gas is R) in Corpus hristi, Texas. kely to happe re systems m llution emiss flare pilot fu lemental fue ling flare gas re systems m ydrocarbon E flares in air p 2004. ory. y and Combus stems, Chemi Page 11 2 John Zink Co e of the flare ents, an FGR flared. 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