08.2021.439.456

Energy and Exergy Analysis for a Steam Cycle of North Refineries Company (NRC)/Baiji, Iraq

Author(s):

Hameed J. Khalaf †, Waad A. Salih‡, *, Aadel A. Alkumait†, Thamir K. Ibrahim†

Affiliation(s):

† Mechanical Engineering department, Tikrit University, Iraq.
‡ North Refineries Company (NRC)/ Baiji, Iraq.

Corresponding Author Email: waad.a.salih43287@st.tu.edu.iq

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

This study presents an energy and exergy analysis for steam cycle in a petrochemical refinery in North Refineries Company (NRC)/Baiji, IRAQ. The study starts with setting up a mathematical model based on mass, energy, and exergy balance equations for each component of the cycle separately, recording the operational data (pressure, temperature, and mass flowrates) for the cycle at real and rated loading. Calculations were done by using ‎(MATLAB) platform. The results of energy analysis showed that the total energy losses were 98.89 MW and 119.85 MW for real and rated loading, respectively. The largest energy dissipation was found in the condensers which represents 32.01% and 29.79% from the total energy loss at the two rating loads, respectively. The 1st-law efficiencies for the cycle at real and rated loading were found to be 36.27% and 38.63%, respectively. The exergy analysis based on the 2nd-law of thermodynamics showed different and interested results, it explained that the total exergy destruction at real and rated loads are 61.58 MW and 75.13 MW, respectively, and the largest destruction in exergy occurs in boilers and found to be 45.99% and 45.25% of the total exergy destruction at real and rated loads, respectively. Turbines, condensers and heat exchangers are following the boilers in the values of exergy destruction and found to be 15.54%, 13.64% and 5.98%, respectively, at real load, and 14.53%, 12.7%, and 6.45%, respectively, at rated load. The 2nd-law efficiency for the two loading rates were 23.65% and 22.6%, respectively.