THNG 09-2013

NG SUT CHO PHP []Sau khi xc nh c vt liu lm bn (da vo n mn ca sn phm v yu t kinh t), ta s la chn ng sut cho php ca vt liu [].ng sut cho php ca vt liu ph thuc vo bn ca vt liu. bn ca vt liu ph thuc vo:nhit - t - gii hn bn ca vt liu ti nhit bn tphng php gia cng vt liu - []* - ng sut tiu chun []* = [N/m2]

n: h s an ton

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ng sut cho php tiu chun []*:

tB gii hn bn ca vt liu khi ko nhit t;tc gii hn chy ca vt liu nhit t;tbl gii hn bn lu ca vt liu nhit t;td gii hn do ca vt liu nhit t;nB, nc, nbl, nd h s an ton theo gii hn bn, chy, bn lu v bin dng do

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Bng la chn cng thc xc nh ng sut cho php tiu chun []* ca vt liu*

Vt liuNhit tnhCng thc xc nh []*ThpCacbon3801 v 2>3802,3 v 4Hp kim thp4201 v 2>4202,3 v 4Hp kim lp otstenit5251 v 2>5252,3 v 4Nhm, ng v hp kim ca chngKhng quy nh2 v 3Titan v hp kim ca n1,2 v 3

NG SUT CHO PHP []ng sut cho php [] c xc nh theo ng sut cho php tiu chun []* theo cng thc sau:[] = . []* Trong : h s hiu chnh , xc nh theo iu kin lm vic ca bn cha (=0.9-1.0)

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H S B SUNG B DY TNH TON C*C c xc nh nh sau:C = Ca + Cb + Cc+ C0Ca-h s b sung do n mn ha hc ca mi trngCb- h s b sung do bo mn c hc ca mi trngCc- h s b sung do sai lch khi ch to, lp rpC0- h s b sung quy trn kch thc

H s b sung do n mn ha hc - CaCa ph thuc vo:n mn ha hc ca mi trngthi gian s dng bn chaNu thi gian s dng bn cha l 10 nm th Ca c la chn nh sau:Ca=0 i vi vt liu c n mn khng ln hn 0,05mm/nm trong mi trng .Ca=1mm i vi vt liu c n mn t 0,05 n 0,1mm/nm khi tip xc vi mi trngCa=0 nu ta dung vt liu lt c tnh bn n mn.c bit, nu hai pha ca bn cha tip xc vi mi trng n mn th h s Ca phi ly ln hn.

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H s b sung do bo mn c hc CbCb c th b qua i vi bn cha.Thc t ngi ta ch tnh Cb khi mi trng bn trong bn cha (hay thit b) chuyn ng vi vn tc>= 20m/s (i vi cht lng) v >=100m/s (i vi cht kh) hay mi trng c nhiu cht rn.

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H s b sung do sai lch khi ch to, lp rp Cc Cc ph thuc vo dng chi tit, cng ngh ch to chi tit v bn cha.

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H s b sung quy trn kch thc C0Kch thc ch to cn c lm trn. i vi thit b lm bng thp hn th kch thc cu to phi ph hp vi kch thc ca thp dt; i vi thit b c th kch thc phi l s nguyn; i vi thit b rn th kch thc chn lch nhau tng 5mm mtKhi tnh ton, thit k th cn tn dng ti a cc chi tit c tiu chun ha thun tin trong vic s dng, sa cha, lp rp v thay th.

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Tng cng cho cc lS tn ti ca l khng nhng lm gim tit din chu lc ca bn m cn gy ra s tp trung ng sut.ng sut mp l l ln nht, n gp ba ln ng sut ti cc v tr khc.ng sut ln nht gn mp l: max = . : gii hn bn ko; :h s tp trung ng sut =3+3.45*d/(D.S) vi d- ng knh l, D-ng knh thn bn cha v S-b dy bn cha

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L khng cn tng cng*ng knh ln nht ca l khng cn tng cng:dmax = 0.37*3D(S-C)(1-k)D: ng knh trong ca thn bn chaS: b dy thn bn chaC: h s d n mnk: h s k n bn ca thn k = P.D / (2,3*[]-P) (S-C)

Cch tng cng cho lV kt cu chia lm 2 loi:vng tng cngbc tng cngVng tng cng : lm cng loi vt liu vi thn v hn cht vo thn (c th hn bn trong, bn ngoi hay c 2 pha)Bc tng cng: c hn vo gia thn v ng. Chiu dy bc nn ly bng chiu dy thn hay ln hn mt t, chiu cao bc 2.5-5S.*

B CHA LNHB cha lnh (LT&C Tank Low Temperature & Cryogenic Tank) c thit k tn tr v vn chuyn kh ha lng nhit di 0oC (di - 100oC)- LNG (-162oC)- Liquefied O2 (-183oC)- Liquefied N2 (-196oC)- Liquefied H2 (-253oC)- Liquefied Helium (-269oC)

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CU TRC B CHA LNH

*B cha lnh thc cht l mt b hnh tr c vch i, khang vnh khuyn gia vch trong v vch ngoi c lp y vt liu cch nhit v c ht chn khng to chn khng ln nhm gim mt mt do bay hi n mc ti thiu.

CU TRC B CHA LNHTypical Single ContainmentContainment Bund Holds Leaked Liquid gi cht lng b r r

CU TRC B CHA LNHTypical Double ContainmentSecondary Containment Holds Leaked Liquid -----(Often Concrete)Thng l b tng

BNH CHA LNHVAPOUR SYSTEMA vapour phase system works like a heat pump. Energy (heat) leaking into the tank is conducted down to the liquid via the racks. This energy is absorbed by the liquid as it vaporizes, cooling the tank to an equilibrium (Teq)The tank lid - the only non vacuum insulated surface, is the main path for heat leak.For a standard 990mm freezer, the lid accounts for over 18% of the surface area.

BNH CHA LNHIn a standard wide neck freezer, so much heat is leaking into the tank that the Teq may be as high as -100C below the lid.This is obviously too high, and the Teq must somehow be reducedIn order to reduce Teq a copper or Aluminium sheet is fitted to the inside of the tank, extending down into the liquid.This provides an additional heat path and causes more LN2 to boil off, absorbing energy and lowering Teq

BNH CHA LNHIn narrow neck vessels the lid only accounts for 3% of the surface areaCoupled with a good vacuum this much reduces the heat leak into the systemBecause of the very low heat leak, Teq is much lower than in a standard tankSome narrow neck vessels will maintain temperatures of -190C directly under the lid

BNH CHA LNHu im:Bnh gn, nh, tin li cho ng gi v vn chuynTng mc an tan v gim nguy him v p sut thpTip nhin liu nhanh (3 pht) v gim mt mt do bay hit tn din tchVn hnh n ginChi ph vn hnh thp

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BNH CHA LNHNhc im:Tiu tn nhiu nng lng cho s ha lngNhy vi s thay i nhit Mt mt do bay hi trong sut qu trnh nhp liu,xut liuMt mt trong qu trnh khng hat ng v boil-offThit k phc tp

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So snh cc dng nhin liu so vi LH2 (Liquified hydrogen)Nng lng trn 1 n v khi lng cao hn so vi nng lng ha thchNng lng trn 1 n v th tch cao hn so vi nng lng CH2 (compressed hydrogen)

So snh cc dng nhin liu so vi LH2 (Liquified hydrogen)Trng lng thp nht so vi cc nng lng cng laiTh tch thp hn CH(i.e. 33%)

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