PSI - Issue 48

6

Mohammed Badr Alzeer/ Structural Integrity Procedia 00 (2019) 000 – 000

Mohammed Badr Alzeer et al. / Procedia Structural Integrity 48 (2023) 363–370

368

6.2 Analysis Relating to Operating Pressure As shown in Figure 4 the frequency of metal loss features increased notably among the miles with high operating pressure, 81% of the features detected between Tartous and Banias – (554/10) to (528/13), where the average of the operating pressure was around 50 (Bar), on the other side 8.5% of the identifications recognized between (528/13) and (513/9) with a recorded operating pressure of 41 (Bar). On the last part, 10% of the overall identifications were detected between the miles of (528/13) and Homs (489/13), the average of the operating pressure is 19 (Bar). It is well understood now that the frequency of metal loss features increases as per operating pressure increases, Furthermore, corrosion rates have increased in direct proportion to the date of installation.

Figure 4. Frequency of the pipe body corrosion features with respect to the operating pressure

6.3 Analysis relating to Metallurgy As shown in Figure 5, the frequency of the metal loss features was significantly higher as we get closer to the upstream in Banias where the line is made mainly of X48 pipes installed in 1961. The frequency of metal loss identifications along that section which corresponds to A in Figure 5 was 7,039 per Kilometre, the average corrosion depth as a proportion of the wall-thickness was 15% or 1.425 (mm), and the corrosion rate was 0.06 (mm /year). The frequency of metal loss features in the miles constructed between 2000 and 2005 which corresponds to sections B and F in the Figure 5 varied between 87 and 93 per Kilometre with a corrosion rate of 0.26 and 0.11 (mm/year) respectively. The frequency of metal loss features among sections C, D, and E which are made of multiple steel grades ranged between 766 and 1855 per Kilometre respectively to the grade, nevertheless, the average depth was around 15% of the nominal wall thickness. By looking at section G which is made of Gr B and commissioned in 1961, it observed as a result of 2008 inspection that the corrosion frequency is 766 per Kilometer with a depth average of 17% and corrosion rate 0.034 (mm/year). From the deterioration rates, it is obvious that the X48 line pipes are more susceptible to corrosion than the Gr B line pipes over all sections. However, metal loss features parameters (length, width, and depth) increased accordingly with the date of pipe installation. In contrast, the average depth growth rate increased respectively as for the line steel grade, it is higher for X52 than Gr B. Figure 6 illustrates the operational