CHLORINE CORROSION OF BLAST FURNACE GAS PIPELINES: ANALYSIS FROM THERMAL PERSPECTIVE

Abstract

With the broad application of dry dedusting of blast furnace gas (BFG), the issue of BFG pipeline corrosion comes up because of chlorine in the BFG. Existing methods in preventing the corrosion, such as spraying alkali or installing corrosion-resistant materials, require a significant amount of investment. This paper conducted a novel thermal analysis of the corrosion mechanism to support the study on corrosion prevention without using additional materials. Firstly, thermal models were established to reflect the relationships among the amount of condensation water, the mass transfer rate, the concentration of chloride ion and the ambient temperature. Secondly, the relationship between BFG temperature and the corrosion rate was obtained via a cyclic exposure experiment. Key factors that affect the pipeline corrosion under various BFG temperatures were identified. Finally, a control scheme of the BFG temperature was proposed to avoid the chlorine corrosion.

Alternate abstract:

Zajedno sa irokom primenom suvog otpra ivanja visokope nog gasa (BFG), pojavljuje se i problem korozija cevi za visokope ni gas zbog hlora koji se nalazi u BFG. Postoje e metode za sprecavanje korozije kao to su prskanje bazama ili ugradnja materijala otpornih na koroziju zahtevaju znatna ulaganja. U ovom radu izvedena je originalna termalna analiza mehanizma korozije da bi se podr ala studija o sprecavanju korozije bez kor enja dodatnih materijala. Najpre su ustanovljeni modeli koji odra avaju odnos izme u kolicine kondenzovane vode, brzine prenosa mase, koncentracije hloridnog jona i temperature okoline. Zatim je uz pomo eksperimenta ciklicnog izlaganja dobijen odnos izme u BFG temperature i brzine korozije. Identifikovan su kljucni faktori koji uticu na koroziju cevi pod uslovima razlicitih BFG temperatura. Konacno, predlo ena je kontrolna ema BFG temperature da bi se izbegla hlorska korozija.