Quantitative Evaluation for Consequences of LNG Releases Based on RBI

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1 Intrnational Journal of Sin Vol.3 o ISS: Quantitativ Evaluation for Consquns of LG Rlass Basd on RBI Xin Ma, Tonghui Shi a Shool of Mhatroni Enginring, Southwst Ptrolum Univrsity, Chngdu , China bstrat a @qq.om LG dmand is inrasing dramatially yar by yar, and th rlatd quipmnt is th important hazardous sour. In th vnt of rlass, th onsqun is usually th fir and xplosion, and it will pos a potntial thrat to th safty of th popl. Thrfor quantitativ valuation for onsquns of LG rlass is vry important to risk managmnt of LG quipmnt, baus it an st up th orrsponding safty distan. On aount of th rprsntativ fluid C1~C didn't onsidr th pool fir onsquns in PI581 onsquns alulation modl. But th pool fir onsqun is th main aidnt onsqun in onsquns of LG rlass. Thrfor, this study provids a nw quantitativ valuation modl for onsquns of LG rlass basd on RBI, and th onsqun aras of pool fir, jt flam, flash fir, BLEVE firballs and VCES ar alulatd rsptivly. Thn it ompars this modl and th PI581 onsquns alulation modl by a ral as. Finally, th analysis of th alulation rsults is don and th rationality and pratiability of this modl ar vrifid. Kywords RBI; LG rlass; quantitativ valuation; risk managmnt; xplosion. 1. Introdution LG (Liqufid atural Gas, LG for short) is a lan, ffiint nrgy us LG an improv th nvironmnt, rdu haz, so our ountry is onstantly inrasing among natural gas in primary nrgy ratio. t prsnt, China LG industry has bgun to tak shap, th numbr of annual imports of LG has rahd millions of tons, by 00, China's oastal aras import LG sal up t (th quivalnt of natural gas m 3 ) [1]. LG riving station, LG, LG ship, LG vhils around th world, vn inluding som rmot aras.in th vnt of LG lakag, will pos a potntial thrat to th safty of th popl.ording to th physial proprtis of LG and LG lakag, low tmpratur ombustion xplosion happns aftr major harm som harm, smothring ation, suh as old xplosion phnomnon.lakag may b many rasons, onsquns of lakag is various, thrfor to stablish a rasonabl LG lakag onsquns of quantitativ alulation modl to prdit th onsquns of lakag is vry important.. Th RBI lak onsquns of quantitativ valuation mthod Risk-basd Insption mthod (RBI) is Basd on Risk analysis, Basd on th inhrnt in th systm or potntial dangr and its onsquns for th qualitativ or quantitativ valuation, on th basis of through formulating th plan of targtd tsting of quipmnt for tsting and maintnan. LG lakag quipmnt failur onsquns an gnrally from th spill ara, burning xplosion quipmnt damag and asualtis ausd by th influn ara, quipmnt rpairs, shutdown ausd by th dirt and indirt onomi losss, t. In addition must also onsidr som influning fators, suh as: th dgr of impat on th nvironmnt, th influn dgr of th rdibility of th ntrpris, t. Th onomi loss du to quipmnt rpair osts, prodution an stimat by using th 145

2 Intrnational Journal of Sin Vol.3 o ISS: mthod of xprt valuation, is rlativly asy to stimat, thrfor fouss on quipmnt damag ara and asualtis onsquns ara alulation. Th ultimat onsqun ara aording to formula (1): max(, ) (1) In th formula: is th final onsqun ara (m ), is th ara for quipmnt damag ausd by burning xplosion onsquns (m ), is th ara for asualtis onsquns (m ). Casualtis onsquns ara an b alulatd by formula (): t f t max(, ) () i i i In th formula: is th burning xplosion asualtis ausd by ara(m ), is th toxiity of th asualtis ausd by th onsquns of th mdium laking ara(m ). Th RBI lak onsquns quantitativ alulation flow hart shown in figur 1: Fig.1 Th flow hart of quantitativ alulation of rlass onsquns basd on RBI 3. LG lakag onsquns quantitativ valuation modl basd on RBI 3.1 LG lakag onsqun analysis LG lakag will aus low tmpratur to human body ansthsia and suffoat. Without adquat prottion masurs, th prson is in lss than 10 aftr waiting for long, will hav th risk of ansthsia in low tmpratur, physiologial funtion and mntal ativity as th tmpratur drops ar falling, hart funtion failur, fll furthr will di. lthough LG stam not poison, but th oxygn ontnt is low, asy to mak th prson suffoat. If inhald pur LG stam and not quikly off, will soon b loss of onsiousnss, and dath in a fw minuts. Usually, th oxygn minimum standard of 10% is not a prmannt damag human body. Corrsponding to th normal air ontains 5.4% of mthan, th oxygn ontnt is 10% []. 5.4% xplosion limit of mthan onntration is gratr than 15%, by a formula () th toxiity of LG lakag asualtis onsquns ara an not onsidr th onsquns. Du to th lakag situation, lighting, ombind with th surrounding nvironmnt situation and situation of LG diffusion, LG laking ombustibl onsquns may inlud: flash fir, pool fir, jt fir, BLEVE firballs and VCES ombustion and othr diffrnt situation. ftr th lakag aidnt pross analysis is shown in figur. 146

3 Intrnational Journal of Sin Vol.3 o ISS: Th hoi of physial paramtrs of LG lakag and aprtur Consult PI581 logistis databas [3], LG rprsntativ fluid is C1 ~ C.LG liquid mixtur of mthan, th dnsity of mthan dnsity as th standard stat of mor than 600 tims, mor storag undr normal prssur and ritial prssur (4.6 MPa), th boiling point is about -16, xplosion limit of 5% ~ 15%. ording to th PI581 rommndd by a group of aprtur (6.5 mm, 5.4 mm, 6.5 mm diamtr and ontainr) lak rat alulation and onsqun ara rsptivly. 3.3 alulating lakag rat and dtrmin th lakag typs Baus of liqufid natural gas (LG) is a kind of suprhatd liquid suddnly vaporat whn liquid lakag, will appar th phnomnon of gas liquid two phas flow at this tim.but dirt vaporation of th liquid fration was vry small (about 3%), so th lakag of liqufid natural gas (LG) spd an b alulatd by liquid.pi581 of liquid lakag rat omputation formula is as follows: g144 p QL= Cd k (3) In th formula: is liquid disharg rat (kg/s); is th disharg offiint, 0.61; is th orifi ara (m ); is liquid dnsity, 450 kg/m 3 ; is for ontainr prssur diffrn btwn prssur and atmosphri prssur (Pa); is alration of gravity, 9.8 m/s. For LG lakag problm, baus th LG storag of atmosphri prssur, th prssur in th ontainr btwn th atmosphri prssur and th gnral prssur to zro.th LG lakag rat an b alulatd aording to th formula: p QL Cd k gh (4) In th formula: h is liquid lvl hight (m) abov th orifi. Fluid lakag, and aording to th siz of th lak hol and lak rat of th formula is a ontinuous lakag or instantanous lakag. Gnrally all th "hols" (lss than 6.5 mm in diamtr) simulation for ontinuous lakag; For othr formulas of por siz, whn lakag 4540 kg taks lss than 3 min, through a givn por siz of th lakag of instantanous lakag, all lowr lakag rat of th simulation for ontinuous lakag [4]. 3.4 quipmnt damag and asualtis ara alulation LG lakag onsquns to onsidr th atmosphri tmpratur, rlativ humidity, wind spd and th influn of th wathr onditions suh as th stability, th ompliatd alulation.pi581 standards, thrfor, givs th simplifid alulation formula of ombustibl onsquns [3], as shown in tabl 1. Tabl 1 Formulas of onsqun aras of LG rlass Lakag typs Equipmnt damag ara ( ) Continu to lak Instantanous lakag ot: x is lak rat, kg/s; X is total lakag, kg. Casualtis ara ( ) 147

4 Intrnational Journal of Sin Vol.3 o ISS: BLEVE firball Instantanous lakag Immdiatly ignit Whthr it is lit Pool fir Th nvironmntal pollution Th liquid pool Dlay Th VCE vapor loud xplosion LG lakag Whthr it is lit Flash fir Gas diffusion Jt fir Continu to lak Immdiatly ignit Whthr it is lit Pool fir Th nvironmntal pollution Th liquid pool Dlay Th VCE vapor loud xplosion Whthr it is lit Flash fir Jt fir 148 Gas diffusion Fig. Th flow hart of LG aidnt onsquns In this papr, ombind with th onditions of LG lakag onsquns aording to th pool fir, jt fir, ignit, BLEVE firballs and VCES lak burning onsquns alulatd rsults ara rsptivly, and thn aording to th spifi vnts of PI581 probability to alulat th omprhnsiv ara Pool ara fir aftrmath LG lakag flow to th ground aftr th formation of inomplt gasifiation liquid pool, pool will form aftr bing lit th fir [5].Pool fir burning vloity an b xprssd as [6] : dm 0.001H (5) dt H In th formula: unit surfa ara is ombustion rat (kg/(m s )); is th hat of ombustion of liquid, J/kg; is th hat of vaporization of liquid, tak 1. J/kg. Liquid pool assumd to b th round pool, flam hight alulatd by formula (6) [6] : dm / dt h 84r ( 0.5 ) a gr In th formula: h is flam hight (m);r is liquid pools radius (m); is th surrounding air dnsity, 1.17 kg /m 3. Rlas of th burning liquid pool total thrmal radiation flux is [6] : dm dm Q r r H dt dt 0.61 ( ) / 7( ) 1 In th formula: Q is th thrmal radiation flux (W); is th ffiiny fator, tak ssum that all hat nrgy from th liquid pool ntr of radiation,it is from th liquid pool ntr x radiation intnsity for: 0.6 (6) (7)

5 Intrnational Journal of Sin Vol.3 o ISS: Qt I= 4 x In th formula: I is thrmal radiation intnsity (. hat ondution offiint, is prfrabl in th absn of a rlativly idal data 1;x is th targt point to th liquid pool ntr distan (m). ording to th provisions of PI581, quipmnt damag of thrmal radiation standard is 37615, mor than all quipmnt will b damagd;standard for th thrmal radiation daths in th 1538, whn mor than will lad to dath. Th pool fir fir quipmnt damag ara and th ara of th asualtis an b rsptivly as follows: 1 i1 Qt Qt 3.4. Th ffts of jt fir ara of produt Combustibl mattr ontinus to lak th jt formation, th lakag in th mouth whn th light will form a jt fir. ording to th formula (11) alulation point hat sour hat valu [7] : L i (8) (9) (10) q Q H (11) In th formula: q is point hat sour thrmal radiation flux (W); is th ffiiny fator, On th jt axis point hat sour to th distan of th thrmal radiation intnsity of x point formula is: Equipmnt an b obtaind whn th radiation intnsity is Whn th radiation intnsity is i qr I (1) 4 x th damag ara of: QLH R (13) availabl asualtis for th ara: QLH R (14) Th onsquns of flash fir ara Flash fir is ombustibl gas or stam lak into th air and mixs with th light of a kind of xplosiv ombustion pross. Flash fir is on of th shortst duration formula, th burning spd, th whol pross is instantanous. So in this papr, w onsidr that flash firs burn in th fir ourrd outsid th sop of radiation damag is vry small, to ignor it, only onsidr LG lakag within th sop of thrmal radiation. So th assumption that ourrd aftr th flash of fir ara is th LG diffusion of inflammabl and xplosiv ara. In this papr, with th sprad of havy gas louds box modl. ssum that lakag of LG havy gas louds of th initial volum, so: V o i m/ (15) ssum that th initial radius of air mass hight is gnral, th initial radius for [8] : R o m o o 1 3 (16) 149

6 Intrnational Journal of Sin Vol.3 o ISS: t any tim with th downwind distan hang of th onntration of havy gas louds is [9] : 1 3 C Cox / Vo Lakag aftr th aidnt, in th pross of transmission du to th motion of th wind, th influn of trrain, th sprad of havy gas louds trajtory for osillation, th band of th xtrnal stor is th hazard ara. Fan-shapd sprad ngl gnrally tak 40, but th ral damag ara is muh smallr, whih is about a 1 ngl band ara, th ara is [9] : D S= 1.xD 0.15x (18) 8 ording to th ritria, for quipmnt damag, flash fir ignition in th ara of th lowr flammabl limit rang 5% as th rul of impat; Flash fir ignition for asualtis, with 100% of th lowr flammabl limit rang whn as a rul of influn. LG limit is 5% ~ 15% in avrag burning in th air, th lowr xplosiv limit by 5%, whn th onntration of th gas is kg/m 3. To 5% of th surfa of th lowr flammabl limit within th sop of influn as ritria, th flash fir quipmnt damag onsqun ara is: D 3 0.3xD x 3 To 100% of th surfa of th lowr flammabl limit within th sop of influn as ritria, th flash fir fir asualtis onsquns ara is: 1.5 (17) (19) D i 3 1.xD 0.15x (0) BLEVE firballs onsquns of an ara BLEVE fir by fir baking is rfrs to th LG ontainr, suh as xtrnal impat ausd by th ontainr is damagd, ausing a larg numbr of hot gas rlasd into th air.enountr fir will produ svr burning ball of fir.th radius of th ball an b alulatd by formula (16) [10] Th firball duration [10] : R 0.37 (1).665M t Firball radiation hat flux from th burning of as follows: M () HM Q t Distans from th ntr of th fir intnsity of thrmal radiation ffts of x point formula is: (3) QT I (4) Whn th fir disastr, th quipmnt damag ara and th ara of th asualtis an b rsptivly is: VCES ara of vapor loud xplosion onsquns 4 i4 QT (5) QT (6) i 150

7 Intrnational Journal of Sin Vol.3 o ISS: s th LG is a suprhatd liquid, so suddnly vaporat whn liquid lakag and vapor loud formation, if rapid aumulation vapor loud xplosion limit and ahiv, mt fir aftr VCES vapor loud xplosion will our. Vapor loud xplosion possibility is xtrmly high and th harmful onsquns of grat form. LG lakag lad to blong to th opn spa of th xplosion, th xplosion prssur ontainr storag mans that th xplosion of th potntial nrgy of LG. Usually this potntial xplosion nrgy us TT quivalnt said, an b alulatd by formula : W T 1.8MH (7) Q ppliation rul of ovrprssur, in th shok wav ovrprssur may aording to th formula [11] : T P Z Z Z (8) P o Z x WQ T T Undr th fft of shok wav quipmnt sondary damag radius alulation formula is as follows [11] : 1/3 KWT R 1 (3175 / WT ) Whn th vapor loud xplosion, th quipmnt damag ara is: 1/3 1/6 5 (9) (30) (31) Prsonnl undr th fft of shok wav of th ardrum ruptur probability is 0.01 th blast wav pak ovrprssur is = pa, th asualtis ara an b obtaind as follows: i5 /3 ( Po / WT QT ) Comprhnsiv onsquns ara Comprhnsiv onsquns ara omputation formula is as follows: R Z (3) P P + P (33) 1 1 i i Chk PI581 [3], th probability of a spifi vnt in form of LG ontinuous lakag and instantanous spill fir probability is 0..Combind with th LG flow hart of aidnt onsqun, it is onludd that spial vnt probability as shown in tabl. Tabl Probabilitis of spifi vnts Lakag ways Th probability of all kinds of rsults Pool fir Jt fir Flash fir BLEVE VCES Continuous lakag Instantanous lakag Th instan Taking a 50 m 3 LPG station dvi prizing formula LG horizontal tank as an xampl, its dsign prssur is 1. MPa, innr diamtr is 850 mm, Ø xtrnal prssur for th standard atmosphri prssur. Slt lakag aprtur is 5.4 mm, is loatd in th axis of storag tank, and assum that liquid pools radius of pool fir is 5 m. Lak rat alulatd by th formula (4) QL kg / s,th simulation is ontinuous laking.pi581 onsquns modl and LG lakag modl alulation rsults as shown in tabl 3. Tabl 3 Calulation rsults of onsquns modl Consqun modl Equipmnt damag ara Casualtis ara 151

8 Intrnational Journal of Sin Vol.3 o ISS: /m /m PI581 onsquns modl Pool fir 99.3 Jt fir LG lakag modl of th Flash fir onsquns BLEVE VCES omprhnsiv Conlusion (1) For LG lakag aidnt, this papr proposs a nw modl, us as analysis, svral major onsqun of LG lakag: pool fir, jt fir, ignit, BLEVE and VCES rsptivly ondutd a quantitativ alulation. On th basis of analyzing th aus of th aidnt, and ombining th PI581 probability of a partiular vnt, omprhnsiv onsquns ara ar obtaind. () It an b sn from tabl 3, th LG lakag onsquns modl to alulat th quipmnt damag ara and th ara of th asualtis wr gratr than by PI581 onsquns modl alulation rsults. This is baus th PI581 onsquns modl, for th rprsntativ fluid mdium to a final stat of C1 ~ C for gas, and dos not tak into aount th pool fir fir onsquns, but th onsqun of LG lakag, as th main pool fir aidnt onsquns. Thrfor, this modl is mor suitabl for th alulation of LG lakag onsquns. (3) LG is mor and mor widly usd, on th lak will afft popl's lif and proprty safty. By mans of quantitativ valuation, LG lakag onsquns an st out th orrsponding saf distan, th rlatd quipmnt for LG risk managmnt and planning is of grat signifian. Rfrns [1] Qun Huang,Fang Xia: fasibility study of China-mad LG storag tanks, atural Gas Industry,010,7:80-8. [] ong liu: Th dangr of liqufid natural gas and safty prottion, atural Gas Industry,004,7: [3] mrian Ptrolum Institut. PI581 Risk- Basd Insption- bas rsour doumnt[s], 000. [4] Zhiyu Gu,Jian Shuai,Shaohua Dong:Quantitativ Risk ssssmnt on Gas Transmission Station with PI 581, atural Gas Industry,006, 5,p [5] Fay, J.: Modl of spills and firs from LG and oil tankrs. Journal of Hazardous Matrials, 003, -3,p [6] Chao Hu,Guoqing Zhu,Wihua Wu, t al.th modl alulation and analysis of th pool fir hazards, Fir Sin and Thnology, 011, 7,p [7] Chngjun Jiang: idnt invstigation and analysis thnology(chmial Industry Prss,China,009),p [8] Mohan M, Panwar T S, Singh M P. Dvlopmnt of dns gas disprsion modl for mrgny prpardnss. tmosphris Environmnt, 1995, 16,p [9] Jiank Liu:nalysis on th Laking Pross of Toxi Gass from Chmial idnt and Dtrmination of th Risky ra, China Safty Sin Journal,00, 1(06),p [10] Zibing Jin:Study On th Ealuat Mthod and Fir Prottion of th LG Storag ausing blv, Fir Safty Sin,004,4,p [11] Zongzhi Wu,Jindong Gao,Xingkai Zhang:Industrial risk idntifiation and valuation(china Mtorologial Prss,Chian,003),p

Utilizing exact and Monte Carlo methods to investigate properties of the Blume Capel Model applied to a nine site lattice.

Utilizing exact and Monte Carlo methods to investigate properties of the Blume Capel Model applied to a nine site lattice. Utilizing xat and Mont Carlo mthods to invstigat proprtis of th Blum Capl Modl applid to a nin sit latti Nik Franios Writing various xat and Mont Carlo omputr algorithms in C languag, I usd th Blum Capl