Wannan taƙaitaccen bayani yana ba da shawarwari don tsara tsarin bututun da aminci don rarraba hydrogen.
Hydrogen ruwa ne mai saurin canzawa wanda ke da yawan zubar ruwa. Haɗakar halaye ne masu haɗari da haɗari, ruwa mai saurin canzawa wanda yake da wahalar sarrafawa. Waɗannan su ne halaye da za a yi la'akari da su yayin zaɓar kayan aiki, gaskets da hatimi, da kuma halayen ƙira na irin waɗannan tsarin. Waɗannan batutuwa game da rarraba gas H2 sune abin da wannan tattaunawa ta mayar da hankali a kai, ba samar da H2, ruwa H2, ko ruwa H2 ba (duba gefen dama).
Ga wasu muhimman abubuwa da za su taimaka muku fahimtar cakuda hydrogen da H2-air. Hydrogen yana ƙonewa ta hanyoyi biyu: deflagration da explosion.
Rufewar iska. Rufewar iska wani yanayi ne na konewa wanda harshen wuta ke ratsawa ta cikin cakuda a saurin subsonic. Wannan yana faruwa, misali, lokacin da wani ƙaramin tushen wuta ya kunna gajimare mai 'yanci na cakuda hydrogen da iska. A wannan yanayin, harshen wuta zai motsa a gudun ƙafa 10 zuwa 100 a kowace daƙiƙa. Faɗaɗawar iskar gas mai zafi cikin sauri yana haifar da raƙuman matsi waɗanda ƙarfinsu ya yi daidai da girman girgijen. A wasu lokuta, ƙarfin girgizar iska na iya isa ya lalata gine-ginen gini da sauran abubuwa a hanyarsa da kuma haifar da rauni.
fashewa. Lokacin da ta fashe, harshen wuta da raƙuman girgiza suna tafiya ta cikin cakuda a saurin supersonic. Rabon matsin lamba a cikin raƙuman fashewa ya fi girma fiye da fashewar. Saboda ƙaruwar ƙarfin, fashewar ta fi haɗari ga mutane, gine-gine da abubuwan da ke kusa. Lalacewar al'ada tana haifar da fashewa idan aka kunna ta a cikin sarari mai iyaka. A irin wannan yanki mai kunkuntar, wutar na iya faruwa ta hanyar ƙarancin kuzari. Amma don fashewar cakuda hydrogen da iska a cikin sarari mara iyaka, ana buƙatar tushen wuta mai ƙarfi.
Rabon matsin lamba a fadin raƙuman fashewa a cikin cakuda hydrogen da iska shine kimanin 20. A matsin lamba na yanayi, rabon 20 shine 300 psi. Lokacin da wannan raƙuman matsin lamba suka haɗu da wani abu mai tsayawa, rabon matsin lamba yana ƙaruwa zuwa 40-60. Wannan ya faru ne saboda nunin raƙuman matsin lamba daga wani cikas mai tsayawa.
Yana da saurin zubewa. Saboda ƙarancin danko da kuma ƙarancin nauyin kwayoyin halitta, iskar H2 tana da yawan zubewa har ma tana ratsawa ko shiga cikin wasu abubuwa.
Hydrogen ya fi iskar gas sau 8 sauƙi, ya fi iska sau 14 sauƙi, ya fi propane sau 22 sauƙi, kuma ya fi tururin fetur sau 57 sauƙi. Wannan yana nufin cewa idan aka sanya shi a waje, iskar H2 za ta tashi da sauri ta ɓace, ta rage duk wata alama ta ɓuɓɓugar ruwa. Amma yana iya zama takobi mai kaifi biyu. Fashewa na iya faruwa idan ana yin walda a kan shigarwa a waje ko a ƙasa na ɓuɓɓugar ruwa ta H2 ba tare da binciken gano ɓuɓɓugar ruwa ba kafin walda. A cikin sararin da aka rufe, iskar H2 na iya tashi da taruwa daga rufin ƙasa, yanayin da ke ba shi damar taruwa har zuwa manyan girma kafin ya fi yiwuwa ya haɗu da tushen wuta kusa da ƙasa.
Wutar da ba ta dace ba. Wutar da kai wani abu ne da ke faruwa inda cakuda iskar gas ko tururi ke ƙonewa ba tare da tushen wuta na waje ba. Haka kuma ana kiransa da "ƙonewa ba tare da izini ba" ko "ƙonewa ba tare da izini ba". Wutar da kai ta dogara ne akan zafin jiki, ba matsin lamba ba.
Zafin wutar lantarki ta atomatik shine mafi ƙarancin zafin da man fetur zai kunna ba zato ba tsammani kafin ya kunna ba tare da wata hanyar wuta ta waje ba idan ya taɓa iska ko wani abu mai hana iska. Zafin wutar lantarki ta atomatik na foda ɗaya shine zafin da yake ƙonewa ba zato ba tsammani idan babu wani abu mai hana iska. Zafin wutar lantarki ta atomatik na iskar gas H2 a cikin iska shine 585°C.
Makamashin kunna wuta shine makamashin da ake buƙata don fara yaɗuwar harshen wuta ta hanyar cakuda mai ƙonewa. Mafi ƙarancin kuzarin kunna wuta shine mafi ƙarancin kuzarin da ake buƙata don kunna wani takamaiman cakuda mai ƙonewa a wani takamaiman zafin jiki da matsin lamba. Mafi ƙarancin kuzarin kunna wuta don iskar gas H2 a cikin 1 atm na iska = 1.9 × 10–8 BTU (0.02 mJ).
Iyakokin fashewa sune matsakaicin da mafi ƙarancin yawan tururi, hazo ko ƙura a cikin iska ko iskar oxygen inda fashewar ta faru. Girman da yanayin muhalli, da kuma yawan man fetur, suna sarrafa iyakokin. Wani lokaci ana amfani da "iyakokin fashewa" a matsayin ma'anar "iyakokin fashewa".
Iyakokin fashewar gaurayen H2 a cikin iska sune vol. 18.3% (ƙasa da iyaka) da vol. 59% (babba iyaka).
Lokacin tsara tsarin bututu (Hoto na 1), mataki na farko shine a tantance kayan gini da ake buƙata don kowane nau'in ruwa. Kuma kowane ruwa za a rarraba shi daidai da sakin layi na ASME B31.3. 300(b)(1) ya ce, "Mai shi ma yana da alhakin tantance bututun aji D, M, matsin lamba mai yawa, da kuma tsafta mai yawa, da kuma tantance ko ya kamata a yi amfani da wani tsarin inganci."
Rarraba ruwa yana bayyana matakin gwaji da nau'in gwajin da ake buƙata, da kuma wasu buƙatu da yawa dangane da nau'in ruwa. Alhakin mai shi kan wannan yawanci yana kan sashen injiniya na mai shi ko injiniyan da aka ba shi aiki a waje.
Duk da cewa Dokar Bututun Tsarin B31.3 ba ta gaya wa mai shi wane abu ne zai yi amfani da shi don wani takamaiman ruwa ba, tana ba da jagora kan ƙarfi, kauri, da buƙatun haɗin kayan. Akwai kuma maganganu guda biyu a cikin gabatarwar lambar waɗanda suka bayyana a sarari:
Kuma a faɗaɗa sakin layi na farko da ke sama, sakin layi na B31.3. 300(b)(1) ya kuma ce: “Mai shinfidar bututun yana da alhakin bin wannan Dokar da kuma kafa ƙa'idodin ƙira, gini, dubawa, dubawa, da gwaji waɗanda ke jagorantar duk sarrafa ruwa ko tsarin da bututun yake ɓangare. Shigarwa.” Don haka, bayan sanya wasu ƙa'idodi na asali don alhaki da buƙatun ayyana nau'ikan sabis na ruwa, bari mu ga inda iskar hydrogen ta dace.
Saboda iskar hydrogen tana aiki a matsayin ruwa mai canzawa tare da ɗigowa, ana iya ɗaukar iskar hydrogen a matsayin ruwa na yau da kullun ko ruwa na Class M a ƙarƙashin rukunin B31.3 don hidimar ruwa. Kamar yadda aka bayyana a sama, rarrabuwar sarrafa ruwa buƙatu ne ga mai shi, muddin ya cika ƙa'idodin nau'ikan da aka zaɓa da aka bayyana a cikin B31.3, sakin layi na 3. 300.2 Ma'anoni a cikin sashin "Ayyukan Hydraulic". Ga ma'anoni masu zuwa don hidimar ruwa na yau da kullun da hidimar ruwa na Class M:
"Aikin Ruwa na Al'ada: Sabis na ruwa da ya shafi yawancin bututun da ke ƙarƙashin wannan lambar, watau ba ya ƙarƙashin ƙa'idodi na azuzuwan D, M, zafin jiki mai yawa, matsin lamba mai yawa, ko tsaftar ruwa mai yawa."
(1) Gubar ruwan tana da yawa har ta kai ga ɗan ƙaramin adadin ruwan da ɓullar ruwa ta haifar na iya haifar da mummunan rauni na dindindin ga waɗanda suka shaƙa ko suka taɓa shi, koda kuwa an ɗauki matakan murmurewa nan take.
(2) Bayan la'akari da ƙirar bututun mai, gogewa, yanayin aiki, da wurin da yake, mai shi ya yanke shawarar cewa buƙatun amfani da ruwan a al'ada bai isa ba don samar da matsewar da ake buƙata don kare ma'aikata daga fallasa.
A cikin ma'anar M da ke sama, iskar hydrogen ba ta cika sharuddan sakin layi na (1) ba saboda ba a ɗauke ta a matsayin ruwa mai guba ba. Duk da haka, ta hanyar amfani da ƙaramin sashe na (2), Dokar ta ba da damar rarraba tsarin hydraulic a cikin aji na M bayan la'akari da "... ƙirar bututu, ƙwarewa, yanayin aiki da wurin..." Mai shi ya ba da izinin tantance yadda ake sarrafa ruwa yadda ya kamata. Bukatun ba su isa ba don biyan buƙatar babban matakin aminci a cikin ƙira, gini, dubawa, dubawa da gwaji na tsarin bututun iskar hydrogen.
Da fatan za a duba Jadawali na 1 kafin a tattauna Tsabtace Haydaroji Mai Zafi (HTHA). An jera lambobi, ƙa'idodi, da ƙa'idodi a cikin wannan teburin, wanda ya haɗa da takardu shida kan batun embrittlement na hydrogen (HE), wani yanayi na tsatsa da aka saba gani wanda ya haɗa da HTHA. OH na iya faruwa a yanayin zafi mai ƙasa da zafi. Idan aka yi la'akari da shi a matsayin nau'in tsatsa, ana iya fara shi ta hanyoyi da yawa kuma yana shafar nau'ikan kayayyaki iri-iri.
HE yana da siffofi daban-daban, waɗanda za a iya raba su zuwa fashewar hydrogen (HAC), fashewar hydrogen stress (HSC), fashewar stress corrosion (SCC), fashewar hydrogen corrosion (HACC), fashewar hydrogen (HB), fashewar hydrogen (HIC). )), fashewar hydrogen mai mayar da hankali kan stress onened hydrogen (SOHIC), fashewar ci gaba (SWC), fashewar sulfide stress cracking (SSC), fashewar soft zone cracking (SZC), da kuma lalata hydrogen high temperature (HTHA).
A cikin mafi sauƙin siffantawa, hydrogen embrittlement wata hanya ce ta lalata iyakokin ƙarfe, wanda ke haifar da raguwar ductility saboda shigar hydrogen atom. Hanyoyin da wannan ke faruwa sun bambanta kuma an bayyana su da wasu sunaye daban-daban, kamar HTHA, inda ake buƙatar hydrogen mai zafi da matsin lamba a lokaci guda don embrittlement, da SSC, inda ake samar da hydrogen atom a matsayin iskar gas mai rufewa da hydrogen. Saboda lalata acid, suna shiga cikin ƙarar ƙarfe, wanda zai iya haifar da karyewa. Amma sakamakon gabaɗaya iri ɗaya ne da duk shari'o'in embrittlement na hydrogen da aka bayyana a sama, inda ƙarfin ƙarfe ke raguwa ta hanyar embrittlement ƙasa da kewayon damuwa da aka yarda da shi, wanda hakan ke saita matakin faruwar wani lamari mai yuwuwar bala'i idan aka yi la'akari da canjin ruwan.
Baya ga kauri bango da aikin haɗin gwiwa na inji, akwai manyan abubuwa guda biyu da za a yi la'akari da su yayin zaɓar kayan aikin gyaran iskar gas na H2: 1. Fuskantar iskar hydrogen mai zafi (HTHA) da 2. Damuwa mai tsanani game da yuwuwar zubewa. Ana tattaunawa kan batutuwan biyu a halin yanzu.
Ba kamar hydrogen na kwayoyin halitta ba, hydrogen na iya faɗaɗawa, yana fallasa hydrogen ga yanayin zafi da matsin lamba mai yawa, yana ƙirƙirar tushen HTHA mai yuwuwa. A ƙarƙashin waɗannan yanayi, hydrogen na atomic yana iya yaɗuwa cikin kayan bututun ƙarfe na carbon ko kayan aiki, inda yake amsawa da carbon a cikin maganin ƙarfe don samar da iskar methane a iyakokin hatsi. Ba tare da ya iya tserewa ba, iskar gas ɗin tana faɗaɗawa, tana ƙirƙirar tsagewa da ramuka a bangon bututu ko tasoshin - wannan shine HTGA. Kuna iya ganin sakamakon HTHA a fili a cikin Hoto na 2 inda tsagewa da tsagewa suka bayyana a bango mai girman inci 8. Sashen bututun girman da ba a san shi ba (NPS) wanda ya gaza a ƙarƙashin waɗannan yanayi.
Ana iya amfani da ƙarfen carbon don hidimar hydrogen lokacin da zafin aiki ya kasance ƙasa da 500°F. Kamar yadda aka ambata a sama, HTHA yana faruwa ne lokacin da aka riƙe iskar hydrogen a babban matsin lamba da zafin jiki mai yawa. Ba a ba da shawarar ƙarfen carbon ba lokacin da ake sa ran matsin lamba na hydrogen zai kasance kusan 3000 psi kuma zafin ya wuce kusan 450°F (wanda shine yanayin haɗari a Hoto na 2).
Kamar yadda za a iya gani daga taswirar Nelson da aka gyara a Hoto na 3, wanda aka ɗauka daga API 941, babban zafin jiki yana da mafi girman tasiri ga tilasta hydrogen. Matsin iskar hydrogen na ɗan lokaci zai iya wuce 1000 psi idan aka yi amfani da shi tare da ƙarfen carbon waɗanda ke aiki a yanayin zafi har zuwa 500°F.
Hoto na 3. Wannan jadawalin Nelson da aka gyara (wanda aka daidaita daga API 941) za a iya amfani da shi don zaɓar kayan da suka dace don hidimar hydrogen a yanayin zafi daban-daban.
A hoto na 3 yana nuna zaɓin ƙarfe waɗanda aka tabbatar za su guji harin hydrogen, ya danganta da zafin aiki da matsin lamba na hydrogen. Karfe masu bakin ƙarfe na Austenitic ba sa jin daɗin HTHA kuma kayan aiki ne masu gamsarwa a duk yanayin zafi da matsin lamba.
Bakin karfe mai siffar Austenitic 316/316L shine mafi amfani ga aikace-aikacen hydrogen kuma yana da ingantaccen tarihin aiki. Duk da cewa ana ba da shawarar maganin zafi bayan walda (PWHT) ga ƙarfen carbon don rage yawan hydrogen da ya rage yayin walda da rage taurin yankin da zafi ya shafa (HAZ) bayan walda, ba a buƙatar sa ga ƙarfen austenitic ba.
Tasirin zafi da ake samu daga maganin zafi da walda ba su da wani tasiri sosai kan halayen injinan ƙarfe na bakin austenitic. Duk da haka, aiki a sanyi na iya inganta halayen injinan ƙarfe na bakin austenitic, kamar ƙarfi da tauri. Lokacin lanƙwasawa da samar da bututu daga bakin ƙarfe na austenitic, halayen injinansu suna canzawa, gami da raguwar ƙarfin kayan.
Idan bakin ƙarfe mai kama da austenitic yana buƙatar ƙirƙirar sanyi, ƙarar ruwan zafi (zafi zuwa kusan 1045°C sannan a kashe shi ko kuma sanyaya shi da sauri) zai dawo da halayen injinan kayan zuwa ƙimarsu ta asali. Hakanan zai kawar da rarrabuwar ƙarfe, faɗakarwa da matakin sigma da aka samu bayan aikin sanyi. Lokacin yin ƙarar ruwan zafi, a sani cewa sanyaya cikin sauri na iya mayar da damuwa ga kayan idan ba a yi amfani da shi yadda ya kamata ba.
Duba teburin GR-2.1.1-1 Tsarin Takaddun Kayan Bututu da Bututu da kuma Tsarin Takaddun Kayan Bututu na GR-2.1.1-2 a cikin ASME B31 don zaɓin kayan da aka yarda da su don hidimar H2. Bututu wuri ne mai kyau don farawa.
Tare da daidaitaccen nauyin atomic na raka'o'in atom 1.008 (amu), hydrogen shine mafi sauƙi kuma mafi ƙanƙanta a kan teburin lokaci-lokaci, saboda haka yana da babban yuwuwar zubewa, tare da mummunan sakamako, zan iya ƙara da cewa. Saboda haka, dole ne a tsara tsarin bututun iskar gas ta yadda zai iyakance haɗin nau'in injina da inganta waɗannan haɗin da ake buƙata da gaske.
Idan ana iyakance wuraren da za a iya samun matsala wajen zubewa, ya kamata a haɗa tsarin sosai, sai dai idan akwai haɗin da aka yi da flange a kan kayan aiki, abubuwan bututu da kayan haɗin. Ya kamata a guji haɗin da aka yi da zare gwargwadon iko, idan ba gaba ɗaya ba. Idan ba za a iya guje wa haɗin da aka yi da zare ba saboda kowane dalili, ana ba da shawarar a haɗa su gaba ɗaya ba tare da rufe zare ba sannan a rufe walda. Lokacin amfani da bututun ƙarfe na carbon, dole ne a haɗa haɗin bututun da butt kuma a yi masa maganin zafi bayan walda (PWHT). Bayan walda, bututu a yankin da zafi ya shafa (HAZ) suna fuskantar harin hydrogen ko da a yanayin zafi na yanayi. Yayin da harin hydrogen ke faruwa galibi a yanayin zafi mai yawa, matakin PWHT zai ragu gaba ɗaya, idan ba a kawar da shi ba, wannan yiwuwar ko da a yanayin yanayi.
Rashin ƙarfin tsarin da aka haɗa shi da dukkan na'urori shine haɗin flange. Don tabbatar da matsewa mai yawa a cikin haɗin flange, yakamata a yi amfani da gaskets na Kammprofile (hoto na 4) ko wani nau'in gaskets. Masana'antun da yawa sun yi shi ta hanya ɗaya, wannan kushin yana da matuƙar afuwa. Ya ƙunshi zoben ƙarfe masu haƙori waɗanda aka haɗa su tsakanin kayan rufewa masu laushi da nakasa. Haƙoran suna tattara nauyin ƙulli a ƙaramin yanki don samar da matsewa mai ƙarfi tare da ƙarancin damuwa. An tsara shi ta yadda zai iya rama saman flange marasa daidaito da kuma yanayin aiki mai canzawa.
Hoto na 4. Gasket ɗin Kammprofile suna da ƙarfe mai ɗaure a ɓangarorin biyu tare da mai laushi.
Wani muhimmin abu a cikin ingancin tsarin shine bawul. Zubewar da ke kewaye da hatimin tushe da flanges na jiki babbar matsala ce. Don hana wannan, ana ba da shawarar zaɓar bawul mai hatimin bellows.
Yi amfani da bututun ƙarfe na carbon 80 na inci 1. A misalinmu da ke ƙasa, idan aka yi la'akari da juriyar masana'antu, tsatsa da juriyar inji bisa ga ASTM A106 Gr B, matsakaicin matsin lamba na aiki da aka yarda (MAWP) za a iya ƙididdige shi a matakai biyu a yanayin zafi har zuwa 300°F (Lura: Dalilin "...don yanayin zafi har zuwa 300ºF..." shine saboda matsin lamba (S) da aka yarda na kayan ASTM A106 Gr B yana fara lalacewa lokacin da zafin ya wuce 300ºF.(S), don haka Daidaito (1) yana buƙatar Daidaita zuwa yanayin zafi sama da 300ºF.)
Idan aka koma ga dabara (1), mataki na farko shine a ƙididdige matsin lamba na fashewar bututun.
T = kauri bangon bututu ban da juriyar injina, tsatsa da masana'antu, a inci.
Kashi na biyu na tsarin shine a ƙididdige matsakaicin matsin lamba na aiki Pa da aka yarda da shi na bututun ta hanyar amfani da ma'aunin tsaro S f zuwa ga sakamakon P bisa ga lissafi (2):
Saboda haka, lokacin amfani da kayan makaranta na 1″ 80, ana ƙididdige matsin lamba na fashewa kamar haka:
Sannan za a yi amfani da Sf na tsaro na 4 bisa ga Shawarwarin Jirgin Ruwa na ASME Sashe na VIII-1 2019, Sashe na 8. UG-101 da aka ƙididdige kamar haka:
Ƙimar MAWP da aka samu ita ce inci 810 psi. tana nufin bututu kawai. Haɗin flange ko ɓangaren da ke da mafi ƙarancin ƙima a cikin tsarin zai zama abin da ke tantance matsin lamba da aka yarda da shi a cikin tsarin.
Bisa ga ASME B16.5, matsakaicin matsin lamba na aiki da aka yarda da shi don kayan haɗin flange na ƙarfe 150 na carbon shine inci 285 psi. a -20°F zuwa 100°F. Aji 300 yana da matsakaicin matsin lamba na aiki da aka yarda da shi na 740 psi. Wannan zai zama ma'aunin iyaka na matsi na tsarin bisa ga misalin ƙayyadaddun kayan da ke ƙasa. Hakanan, a cikin gwaje-gwajen hydrostatic kawai, waɗannan ƙimar za su iya wuce sau 1.5.
A matsayin misali na ƙayyadadden kayan ƙarfe na carbon, ƙayyadadden layin sabis na iskar gas na H2 wanda ke aiki a yanayin zafi a ƙasa da matsin lamba na ƙira na inci 740 psi., na iya ƙunsar buƙatun kayan da aka nuna a cikin Jadawali na 2. Waɗannan nau'ikan ne waɗanda za su iya buƙatar kulawa don a haɗa su cikin ƙayyadadden:
Baya ga bututun da kanta, akwai abubuwa da yawa da suka samar da tsarin bututun kamar kayan aiki, bawuloli, kayan aiki na layi, da sauransu. Duk da cewa za a haɗa da yawa daga cikin waɗannan abubuwan a cikin bututun don tattauna su dalla-dalla, wannan zai buƙaci shafuka da yawa fiye da yadda za a iya ɗauka. Wannan labarin.