N'agbanyeghị inherent corrosion eguzogide nke igwe anaghị agba nchara ọkpọkọ, igwe anaghị agba nchara ọkpọkọ arụnyere na mmiri gburugburu na-n'okpuru dị iche iche nke corrosion n'oge ha na-atụ anya life.This corrosion nwere ike iduga efehe emissions, ngwaahịa ọnwụ na nwere risks.Offshore n'elu ikpo okwu nwe na rụọ ọrụ nwere ike ibelata ihe ize ndụ nke corrosion site n'ịkọwa ike ọkpọkọ ihe na-enye mma corrosional injection, mgbe ha ga-anọgide na-anọgide na-eguzogide ọgwụ chemical. , na nhazi ngwá ọrụ na ihe mmetụta iji hụ na corrosion adịghị egwu iguzosi ike n'ezi ihe nke ọkpọkọ arụnyere na imebi nchekwa.
Enwere ike ịchọta corrosion nke mpaghara n'ọtụtụ ikpo okwu, ụgbọ mmiri, ụgbọ mmiri, na ọkpọkọ na nrụnye ndị dị n'ikpere mmiri. Nke a corrosion nwere ike ịbụ n'ụdị pitting ma ọ bụ crevice corrosion, nke ọ bụla n'ime ha nwere ike imebi mgbidi ọkpọkọ ma mee ka mmiri pụta.
Ihe ize ndụ nke corrosion ka ukwuu mgbe okpomọkụ na-arụ ọrụ nke ngwa ahụ na-abawanye. Okpomọkụ nwere ike ime ka mbibi nke ihe nkiri oxide dị n'èzí na-echebe nke tube, si otú ahụ na-akwalite nhazi nke pitting corrosion.
N'ụzọ dị mwute, localized pitting na crevice corrosion nwere ike isi ike ịchọpụta, na-eme ka ụdị corrosion ndị a siri ike ịmata, ịkọ na imewe maka.Given ndị a ize ndụ, ikpo okwu nwe, ọrụ na designees kwesịrị ịkpachara anya mgbe ahọpụta ndị kasị mma piping ihe maka ha ngwa.Material nhọrọ bụ ha mbụ akara nke agbachitere megide corrosion, otú inweta ya ziri ezi dị mkpa. valent Number (PREN) .Ka ọnụ ahịa PREN dị elu nke metal, ka ọ dị elu na-eguzogide corrosion mpaghara.
Edemede a ga-enyocha otu esi amata pitting na crevice corrosion na otu esi ebuli nhọrọ akụrụngwa tubing maka ngwa mmanụ na gas dị n'ụsọ mmiri dabere na uru PREN nke ihe ahụ.
Mpaghara corrosion emee na obere ebe tụnyere izugbe corrosion, nke bụ ihe edo na metal elu.Pitting na crevice corrosion na-amalite na-etolite na 316 igwe anaghị agba nchara ọkpọkọ mgbe metal si mpụta chromium-ọgaranya passive oxide film ruptures n'ihi ikpughe na corrosive fluids, gụnyere nnu water.Chloride-ọgaranya offshorine, nke ọma na gburugburu ebe obibi nke matubta na okpomọkụ dị ka oké osimiri, dị ka nke ọma n'elu oké osimiri. nwere ike imebi ihe nkiri passivation a.
pitting.Pitting corrosion na-eme mgbe ihe nkiri passivation na ogologo ọkpọkọ na-ebibi, na-akpụ obere oghere ma ọ bụ olulu n'elu ọkpọkọ ahụ. olulu ndị dị otú ahụ nwere ike ịmalite ka mmeghachi omume electrochemical na-ewere ọnọdụ, na-eme ka ígwè dị na ígwè ahụ gbazee n'ime ngwọta dị na ala nke olulu ahụ. Ígwè gbazere ahụ ga-agbasasị n'elu olulu ahụ ma ọ bụ oxide oxide na-eme ka ọ bụrụ ihe na-eme ka ọ dịkwuo elu. lerate, corrosion na-esiwanye ike, ma nwee ike iduga perforation nke mgbidi ọkpọkọ na-eduga na ntapu.
Tubing bụ ndị ọzọ susceptible ka pitting corrosion mgbe elu elu ya bụ mmeru (Figure 1) .Dịka ihe atụ, mmetọ si ịgbado ọkụ na egweri arụmọrụ nwere ike imebi passivating oxide oyi akwa nke ọkpọkọ, si otú akpụ na accelerating pitting corrosion.The otu na-aga n'ihi na nanị emeso mmetọ si ọkpọkọ. Ọzọkwa, dị ka kristal na-eme ka kristal na-emepụta ihe na-eme ka brine na-emepụta ihe na-eme ka brine na-emepụta ihe na-eme ka brine na-emepụta ihe na-eme ka brine na-emepụta ihe na-eme ka brine na-emepụta ihe na-eme ka brine na-emepụta ihe na-eme ka brine na-eme ka ọ ghara ịdị na-eme ka brine na-emepụta ihe na-eme ka brine na-emepụta ihe na-eme ka brine na-emepụta ihe na-eme ka ọ bụrụ na brine na-eme ka ọ bụrụ ihe na-eme ka ọ bụrụ na brine na-eme ka brine na-emepụta ihe na-eme ka ọ bụrụ ihe na-eme ka ọ ghara ịdị na-ekpo ọkụ na brine. e oyi akwa na nwere ike iduga pitting corrosion. Iji gbochie ụdị mmetọ ndị a, na-edebe ọkpọkọ gị ọcha site n'iji mmiri dị ọcha na-asachapụ ha mgbe niile.
Ọgụgụ 1 - 316 / 316L igwe anaghị agba nchara nke ejiri acid, brine na nkwụnye ego ndị ọzọ emetọọ na-enwe mmetụta dị ukwuu na nsị corrosion.
crevice corrosion.N'ọtụtụ ọnọdụ, onye na-arụ ọrụ nwere ike ịmata pitting ngwa ngwa. Otú ọ dị, crevice corrosion adịghị mfe ịchọpụta ma na-ebute ihe ize ndụ dị ukwuu nye ndị ọrụ na ndị ọrụ. Ọ na-emekarị na ọkpọkọ nke nwere oghere siri ike n'etiti ihe ndị gbara ya gburugburu, dị ka ọkpọkọ na-ejide ya na clips ma ọ bụ ọkpọkọ nke a na-ejikọta ya n'akụkụ n'akụkụ. Mgbe brine na-abanye n'ime kemịkal na-eme ihe ike (Chloride solution) ebe n'ime oge na-akpata accelerated crevice corrosion (Figure 2) .N'ihi na crevices onwe ha na-abawanye ohere nke corrosion, crevice corrosion nwere ike ime na okpomọkụ dị ala karịa pitting corrosion.
Ọnụọgụ 2 - Crevice corrosion nwere ike ịmalite n'etiti ọkpọkọ na nkwado ọkpọkọ (n'elu) na mgbe a na-etinye ọkpọkọ n'akụkụ ebe ndị ọzọ (n'ala) n'ihi nhazi nke ihe ngwọta acidified ferric chloride na-eme ihe ike na-eme ihe na-eme ihe ike na-ekpo ọkụ.
Crevice corrosion na-emekarị simulates pitting corrosion mbụ na crevice nke a kpụrụ n'etiti ogologo ọkpọkọ na ọkpọkọ nkwado ọkpọkọ. Otú ọ dị, n'ihi mmụba Fe ++ na-arịwanye elu na mmiri dị n'ime mgbawa ahụ, oghere mbụ na-ebuwanye ibu ma buru ibu ruo mgbe ọ na-ekpuchi ọkpụkpụ dum. N'ikpeazụ, crevice corrosion nwere ike ịgbanye ọkpọkọ.
Ngwongwo siri ike bụ ihe ize ndụ kasị ukwuu nke corrosion. Ya mere, ọkpọkọ ọkpọkọ nke na-ekpuchi ọtụtụ gburugburu nke ọkpọkọ na-emekarị ka ọ bụrụ ihe ize ndụ dị ukwuu karịa oghere ndị na-emeghe, nke na-ebelata njikọ dị n'etiti ọkpọkọ na nkwụsịtụ.
Enwere ike igbochi pitting na crevice corrosion nke ọma site n'ịhọrọ metal alloy kwesịrị ekwesị maka ngwa ahụ. Ndị na-akọwapụta kwesịrị iji nlezianya họrọ ihe kachasị mma iji belata ihe ize ndụ nke corrosion dabere na gburugburu ebe ọrụ, usoro nhazi na mgbanwe ndị ọzọ.
Iji nyere ndị na-akọwa nkọwa na-ebuli nhọrọ ihe, ha nwere ike iji metal 'PREN ụkpụrụ iji chọpụta nguzogide ha na corrosion mpaghara. PREN nwere ike gbakọọ site na chemical mejupụtara nke alloy, gụnyere chromium (Cr), molybdenum (Mo), na nitrogen (N) ọdịnaya, dị ka ndị a:
PREN na-abawanye na ọdịnaya nke ihe ndị na-eguzogide corrosion chromium, molybdenum na nitrogen na alloy. Mmekọrịta PREN na-adabere na okpomọkụ dị oke egwu (CPT) - okpomọkụ kachasị dị ala nke a na-ahụ corrosion pitting - maka ihe dị iche iche igwe anaghị agba nchara n'ihe metụtara chemical mejupụtara. valent na obere mmụba na CPT ma e jiri ya tụnyere alloy, ebe nnukwu mmụba na PREN na-egosi mmụba dị ịrịba ama karịa maka CPT dị elu.
Isiokwu 1 atụnyere ụkpụrụ PREN dị iche iche alloys ndị a na-ejikarị na mmanụ na gas ngwa ngwa.Ọ na-egosi otú nkọwapụta nwere ike isi meziwanye nguzogide corrosion site na ịhọrọ ọkpọkọ ọkpọkọ dị elu.
Ọnụ ọgụgụ dị elu nke nickel (Ni) na igwe anaghị agba nchara na-eme ka nkwụsị nke corrosion dịkwuo elu. Otú ọ dị, ọdịnaya nickel nke igwe anaghị agba nchara abụghị akụkụ nke PREN equation. N'ọnọdụ ọ bụla, ọ na-abakarị uru ịkọwapụta igwe anaghị agba nchara na nnukwu nickel dị elu, n'ihi na ihe a na-enyere aka ịmaliteghachi ihe ndị na-egosi ihe ịrịba ama nke corrosion mpaghara. pipe.Martensite bụ ihe na-achọghị crystalline na-adọ na metals na-ebelata igwe anaghị agba nchara si iguzogide localized corrosion yana chloride-induced stress cracking.A elu nickel ọdịnaya nke dịkarịa ala 12% na 316/316L bụkwa na-achọsi ike maka ngwa metụtara elu mgbali gaseous hydrogen.The kacha nta nickel enweghị ọkọlọtọ chọrọ na 316 ntụ ntụ hydrogen.
Corrosion mpaghara nwere ike ime n'ebe ọ bụla na ọkpọkọ eji na mmiri mmiri. Otú ọ dị, pitting corrosion yikarịrị ka ọ ga-eme na mpaghara ndị emetọworị, ebe corrosion crevice yikarịrị ka ọ ga-eme na ebe ndị nwere oghere dị warara n'etiti ọkpọkọ na ngwa ngwa na-arị elu. Iji PREN dị ka ihe ndabere, onye na-akọwapụta nwere ike họrọ ihe kacha mma ọkpọkọ alloy iji belata ihe ize ndụ nke ụdị corsion ọ bụla.
Otú ọ dị, buru n'uche na e nwere ndị ọzọ variables nwere ike imetụta corrosion ize ndụ.Dịka ihe atụ, okpomọkụ na-emetụta pitting iguzogide nke igwe anaghị agba nchara.N'ihi na-ekpo ọkụ na mmiri climates, 6 molybdenum super austenitic ma ọ bụ 2507 super duplex igwe anaghị agba nchara ọkpọkọ kwesịrị ka a kpọrọ ihe n'ihi na ihe ndị a nwere magburu onwe nguzogide na localized corrosion na chloride stress cracking.N'ihi na oyi na-atụ oyi 6 / 1. .
Ndị na-ahụ maka ikpo okwu na ndị na-arụ ọrụ n'ọdụ ụgbọ mmiri nwekwara ike ime ihe iji belata ihe ize ndụ nke corrosion mgbe etinyere tubing. Ha kwesịrị ịdị na-edebe ọkpọkọ dị ọcha ma na-agbanye mmiri dị ọcha mgbe niile iji belata ihe ize ndụ nke ikpochapu corrosion. Ha kwesịkwara inwe ndị ọkachamara na-ahụ maka nlekọta na-emeghe tubing clamps n'oge nyocha oge niile iji chọpụta ọnụnọ nke crevice corrosion.
N'ịgbaso usoro ndị ahụ akọwapụtara n'elu, ndị nwe ikpo okwu na ndị na-arụ ọrụ nwere ike ibelata ihe ize ndụ nke tubing corrosion na ntapu ndị metụtara ya na gburugburu mmiri, na-eme ka nchekwa na arụmọrụ dịkwuo mma, na-ebelata ohere nke mfu ngwaahịa ma ọ bụ ntọhapụ nke mgbapụ.
Brad Bollinger is the Oil and Gas Marketing Manager for Swagelok Company.He can be reached at bradley.bollinger@swagelok.com.
The Journal of Petroleum Technology bụ akwụkwọ akụkọ flagship nke Society of Petroleum Engineers, na-enye nkọwa nke ikike na njirimara na ọganihu na teknụzụ nyocha na mmepụta ihe, okwu ụlọ ọrụ mmanụ na gas, na akụkọ gbasara SPE na ndị òtù ya.