The entire study has been developed c/o TECNIMONT S.p.A, an Italian company that works in the field of plant engineering, mainly in the hydrocarbon sector (petrochemical, fertilizers, oil & gas refining). The aim of this work was to set-up a material selection for items and streams from three units of a refinery: Diesel Hydrotreatment unit, Sour Water Stripper and Sulfur Recovery Unit. As a first action, an investigation through the possible corrosion mechanism that could take place in that environment was conducted. This activity was carried out by evaluating the parameters given by international standards (API, ASTM, NACE etc.) that were used to define the conditions in which the highlighted corrosion phenomena occur. Moreover, a preliminary differentiation was made corrosion mechanisms that are due to process condition (internal) and exposure to environment (external). Aim of this thesis was to define the corrosion reactions occurring in the internal side and to develop a selection material philosophy. External region corrosion mechanisms were also considered for better understanding the whole process, but not investigated in detail as out of the scope of this dissertation. In addition, a detailed investigation on the cooling water was made to study the possible corrosion mechanisms in the cooling water network being particularly careful on heat exchangers. In the second part of the work, the stream parameters coming from “Heat and material balance” documents were analyzed to select the suitable material of construction based on most critical conditions. In the last chapters a brief description of the process is given, and the material selection is discussed, with some comments on the particularity for each unit.
L'intero studio è stato sviluppato c/o TECNIMONT s.p.A, azienda italiana che opera nel campo dell'impiantistica, principalmente nel settore degli idrocarburi (petrolchimica, fertilizzanti, raffinazione di petrolio e gas). L'obiettivo di questo lavoro era la selezione di materiali per gli apparecchi e le tubazioni di tre unità di una raffineria: unità di desolforazione del diesel, unità trattamento acque acide e unità di recupero dello zolfo (SRU). Inizialmente, sono stati considerati i possibili meccanismi di corrosione, a seconda delle varie condizioni. Questa attività è stata effettuata valutando i parametri forniti dalle norme internazionali (API, ASTM, NACE, ecc.) che sono state utilizzate per definire le condizioni in cui si verificano i fenomeni di corrosione evidenziati. Inoltre, è stata fatta una preliminare distinzione tra meccanismi di corrosione che sono causati dal fluido di processo (corrosione interna) rispetto a quelli causati dall'esposizione all'ambiente (corrosione esterna). Scopo di questa tesi era quello di definire le reazioni di corrosione che si verificano nel lato interno e di sviluppare una filosofia per la selezione del materiale. Sono stati presi in considerazione anche i meccanismi di “corrosione esterna” per una migliore comprensione dell'intero processo, ma non sono stati studiati in dettaglio in quanto esulano dallo scopo di questa tesi. Inoltre, sono stati approfonditi i possibili meccanismi di corrosione che possono presentarsi nella rete dell’acqua di raffreddamento, prestando particolare attenzione agli scambiatori di calore. Nella seconda parte, sono stati analizzati i parametri di processo ottenuti dai documenti denominati “bilancio materiale”. Considerando le condizioni più critiche, questi hanno permesso di selezionare il materiale più adatto. Infine, dopo aver fornito una breve descrizione del processo, è stata discussa la selezione dei materiali, con alcuni commenti sulle particolarità di ciascuna unità.
Corrosion assessment and material selection for three units of refinery : Diesel hydrotreatment, sour water stripper, sulphur recovery unit
SALE, ALESSANDRA
2018/2019
Abstract
The entire study has been developed c/o TECNIMONT S.p.A, an Italian company that works in the field of plant engineering, mainly in the hydrocarbon sector (petrochemical, fertilizers, oil & gas refining). The aim of this work was to set-up a material selection for items and streams from three units of a refinery: Diesel Hydrotreatment unit, Sour Water Stripper and Sulfur Recovery Unit. As a first action, an investigation through the possible corrosion mechanism that could take place in that environment was conducted. This activity was carried out by evaluating the parameters given by international standards (API, ASTM, NACE etc.) that were used to define the conditions in which the highlighted corrosion phenomena occur. Moreover, a preliminary differentiation was made corrosion mechanisms that are due to process condition (internal) and exposure to environment (external). Aim of this thesis was to define the corrosion reactions occurring in the internal side and to develop a selection material philosophy. External region corrosion mechanisms were also considered for better understanding the whole process, but not investigated in detail as out of the scope of this dissertation. In addition, a detailed investigation on the cooling water was made to study the possible corrosion mechanisms in the cooling water network being particularly careful on heat exchangers. In the second part of the work, the stream parameters coming from “Heat and material balance” documents were analyzed to select the suitable material of construction based on most critical conditions. In the last chapters a brief description of the process is given, and the material selection is discussed, with some comments on the particularity for each unit.| File | Dimensione | Formato | |
|---|---|---|---|
|
tesi magistrale Sale Alessandra.pdf
non accessibile
Descrizione: Testo della tesi
Dimensione
9.59 MB
Formato
Adobe PDF
|
9.59 MB | Adobe PDF | Visualizza/Apri |
I documenti in POLITesi sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
https://hdl.handle.net/10589/150017