Exergy Study of Sour Water Stripper Unit of Delayed Coker Unit in a Refinery plant: A Real Start-Up Plant

Ibrahim, Ahmed Y.; Ashour, Fatma H.; Gadallah, Mamdouh A.

doi:10.21608/ejchem.2021.64230.3375

Exergy Study of Sour Water Stripper Unit of Delayed Coker Unit in a Refinery plant: A Real Start-Up Plant

Document Type : Original Article

Authors

¹ Department of Chemical Engineering, Cairo University, Giza 12613, Egypt

² Department of Chemical Engineering, Port Said University, 42526, Port Fouad, Egypt

³ Department of Chemical Engineering, The British University in Egypt, Misr-Ismalia Road, El-Shorouk City, 11837, Cairo, Egypt

10.21608/ejchem.2021.64230.3375

Abstract

Process sour water produced from refinery contains some hazardous pollutants as (H2S and NH3). Sour water stripper units remove both compounds from water. The two stripped pollutants are sent to Sulphur recovery unit to produce Sulphur and prevent any acidic emissions against environmental regulations. The sour water stripper unit serving the delayed Coker unit was simulated with Aspen HYSYS V.11 and an exergy study was conducted on different equipment. While energy is transformed from a form to another, exergy is destructed in an irreversible process. The total exergy is equal to physical and chemical exergies. Physical exergy is calculated through HYSYS and chemical exergy is calculated through a series of equations embedded in excel. The exergy destruction rates, the destruction efficiency and the percentage share of the destruction of each equipment was calculated. The total unit destruction rate was 2996.25 kW. The stripper showed the highest destruction rate 2592.23 kW and a percentage share of 86.52 % of total destruction. The overall efficiency of exergy is 81.58%. A comparison was conducted between the exergy results of this study with two other exergy studies performed in the same refinery plant. The columns in the three studies showed the highest destruction rates exceeding 78% of the total destruction of each unit. The air coolers showed the second- highest destruction rates in their units with a percentage share exceeding 7% of total destruction. The pumps showed the lowest destruction rates with values of less than 1% of the total destruction of each unit.

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