Kev ua cov roj thiab roj feem ntau cuam tshuam nrog impurities, rhuav tshem cov tebchaw rau hauv lawv lub hauv paus ntsiab lus, thiab ua haujlwm ntawm ntau qhov kub thiab txias -- qee qhov lawv siab heev.
Cov hauv qab no yog qee qhov feem ntau cov corrosive compounds tau ntsib nyob rau hauv ntau yam txheej txheem ua hauj lwm nyob rau hauv cov roj thiab roj kev lag luam.
Sulphur: Tam sim no nyob rau hauv raw crude, sulfur sib xyaw nrog lwm cov ntsiab lus los tsim sulfides, sulfuric acids, polythionic acids, thiab lwm yam aggressive compounds. Sulfur kuj tuaj yeem ua rau sulphidation ntawm cov hlau ntawm qhov kub thiab txias.
Naphthenic Acid: Ib pawg ntawm cov organic acids feem ntau pom nyob rau hauv Western thiab Mid-East US cov roj crude.
Polythionic Acid: Feem ntau tsim thaum cov khoom siv tsis ua haujlwm, cov kua qaub no yog tshwm sim los ntawm sulfide, noo noo, thiab oxygen interacting.
Chlorides: Feem ntau pom muaj nyob rau hauv catalysts, dej txias, thiab roj crude, ntsev yuav ua rau kom corrosion kuj. Piv txwv ntawm chlorides muaj xws li magnesium chloride thiab calcium chloride.
Cov pa roj carbon dioxide: Ib qho khoom siv los ntawm cov nroj tsuag hydrogen thiab cov txheej txheem catalytic tawg, carbon dioxide tuaj yeem tsim carbonic acid thaum ua ke nrog cov dej noo.
Ammonia: Feem ntau pib tsim lwm yam tshuaj corrosive -- xws li ammonium chloride -- ammonia yog ib qho tshwm sim ntawm hydrogen interacting nrog nitrogen hauv feedstocks.
Cyanides: Lub luag haujlwm rau kev txhim kho corrosion, cyanide feem ntau tsim thaum lub sij hawm tawg ntawm feedstocks siab hauv nitrogen.
Hydrogen Chloride: Qhov tshwm sim ntawm hydrolysis ntawm magnesium chloride thiab calcium chloride, hydrogen chloride muaj nyob rau hauv ntau lub vapor ntws. Thaum condensed, nws hloov mus rau hydrochloric acid -- tus neeg sawv cev hnyav heev.
Sulfuric Acid: Tsim thaum sulfur trioxide, dej, thiab oxygen ua ke, qhov sib xyaw ua ke no tseem ua haujlwm ua cov txheej txheem hauv cov nroj tsuag alkylation.
Hydrogen: Txawm hais tias tsis ncaj qha corrosive, hydrogen yog ib qho tseem ceeb hauv steel embrittlement thiab cuam tshuam nrog lwm cov tebchaw los tsim cov tshuaj corrosive.
Phenols: Feem ntau ntsib hauv cov txheej txheem cuam tshuam nrog cov dej qaub strippers.
Oxygen: Zoo li hydrogen, oxygen tsis yog kev hem thawj ncaj qha. Qhov tseeb, cov pa oxygen yog ib qho tseem ceeb hauv kev ua kom cov hlau tsis huv ntawm cov txheej txheem passivation. Txawm li cas los xij, nws kuj tseem siv rau hauv ntau cov txheej txheem uas tuaj yeem ua rau oxidation lossis scaling.
Carbon: Tsis tas li ntawd ncaj qha corrosive. Txawm li cas los xij, tuaj yeem ua rau carburization ntawm qhov kub siab dua, ua rau cov hlau embrittlement thiab txo cov corrosion kuj tso cai rau lwm cov corrosive tebchaw los pib tawm tsam.
Qhov no muab cov hlau tsis muaj steel nyob rau hauv ib txoj hauj lwm uas ob peb lwm cov hlau tuaj yeem sib phim. Thaum cov pa roj carbon steel yog tsim nyog rau qee qhov kub qis, -siab, lossis -corrosion, ntau yam stainless hlau alloys muaj kom ntseeg tau tias muaj kev xaiv los muab kev tiv thaiv txawm tias cov roj corrosive tshaj plaws thiab cov roj ua kom zoo dua qub.