PTQ Q2 2026 Issue

materials. Upon heating, the original sample reduced by 35.3% in weight due to the loss of non-ferromagnetic materials.

MagAFS testing kit

New filter cartridges

Testing kit installed in filter assembly of A roma #2 plant on Nov. 4, 2024

A portion of the particles smaller than 75 µm was dis- solved in toluene and shaken with a supersonic vibrator to break up any lumps or coag- ulates of the solid particles in the samples. The shaken samples were then settled for 30 minutes to remove larger particles before the particle size distribution (PSD) of the cleared liquids was analysed by an HLB-550 analyser (with an upper particle size detection limit of 6,000 nm), with the PSD curve plotted in Figure 4 . The PSD curve shows that particles larger than 150 nm (0.15 µm) were effectively removed, with the majority in the 260-300 nm (0.26-0.30 µm) range and a somewhat smaller amount in the 1,500-1,800 nm range. This result implies that the MagAFS filter was highly effective at removing small particles. Filtered particles smaller than 150 nm were probably masked by the curve due to their low abundance. Filtered particles ranging from 4,500-6,000+ nm (4.5-6.0+ µm) accounted for a major portion of the particles detected by the analyser, but some of them may have been unbroken lumps or coagulates. Nevertheless, they are still too small to be removed by cartridge filters. Cleaning up the hydrocracker feed stream The reactor catalyst cycle length of the hydrocracker is lim- ited by excessive reactor pressure drop. The magnitude and rate of increase in pressure drop are unpredictable, which makes cycle management a challenge when pressure drop problems develop. The costs to continue operating at high

Figure 3 Installing new cartridges and MagAFS testing kit into S103B assembly

pressure drop are very high, especially in a high-margin unit such as a hydrocracker. The detrimental effects of increased pressure drop are summarised as follows: • Reduced feed rate significantly impacts the profitability of the hydrocracker. • Reduced recycle gas circulation rate, leading to fewer hydrogenation reactions, causes increased catalyst coking and worsens product selectivity. • Premature turnaround or unexpected shutdown caused by catalyst deactivation or reactor plugging is extremely costly. • Non-uniform bed pressure drops cause flow maldistribu - tion and localised hot spots in the catalyst bed of the reac- tor and may trigger temperature excursions. The material which causes at least a part of the reactor bed plugging and pressure drop enters the hydrocracker as small solid particles in the fresh feed. These particles may be generated from catalyst fines of upstream reactors, such as fluid catalytic cracking (FCC) catalyst fines in cycle oils or coker fines in the coke tar liquid, or brought in with straight- run distillates.

Figure 4 Particle size distribution of particles smaller than 75 µm removed by MagAFS filter kit

PTQ Q2 2026