Gas 2025 Issue

Ref H Ref E Ref F Ref G Ref D Ref C Ref B Ref A

1 , 000

2 , 000

AC, ppmv

CO, ppmv

configurations. The following overview examines the spe - cialised catalysts developed for ROG purification. OleMax 100 series catalyst (see Figure 5 ) is derived from the first generation of C₂ front-end acetylene selective hydrogenation catalysts used in the early days of steam cracking technology, offered with different nickel load - ings to cover a wide range of conversion activities. With very high physical robustness, tolerance towards various sulphur compounds and concentrations, and even co-ab - sorption of heavy metal contamination, it delivers reliable conversion of O2, NOx, Ac, and MA/PD. OleMax 120 series is specifically developed for zero-to- low sulphur-containing streams. This silver-based catalyst will quantitatively convert oxygen and nitric oxides while ethylene is virtually unaffected. It has high selectivity towards O₂ and NOx conversion, moderate acetylene con - version, negligible ethylene losses, and lower temperature operations. OleMax 100 series has demonstrated successful clean-up of ROG streams from different sources over a wide range of feed compositions. In all cases, acetylene is converted to below the upper specification limits (see Figure 6 ), while ethylene losses are low within the projected ranges (see Figure 7 ). CO variations and fluctuations did not cause operational or safety concerns. To support the three discussed category cases with real field examples, a closer look at a few selected projects can provide deeper insights. For example, pressure variations are notable across all cases. Operating pressure, combined with hydrogen and CO partial pressures, represents a Figure 5 OleMax 101 has demonstrated remarkable stabil - ity with a wide range of CO levels

crucial design criterion for catalyst selection and operating parameter determination. The versatility of the catalyst portfolio becomes evident when examining acetylene and oxygen content variations across different streams. Category #1 demonstrates high acetylene content with negligible oxygen presence, while Category #2, particularly in low-pressure applications, exhibits significant oxygen levels. These variations reinforce the fundamental principle that each off-gas stream presents unique characteristics, necessitating detailed compositional analysis for optimal configuration and product selection. Field observations demonstrate that feed stream com - positions exhibit frequent variations, reflecting changes in refinery source conditions. Such compositional fluctuations must be accounted for in ROG purification system designs to ensure consistent performance. The nickel-based catalyst achieves complete and simultaneous clean-up to below the detection limits of acetylene and oxygen. Strong fluctuations of the incoming contaminants are fully tolerated by the nickel catalyst, and no off-specification incidents were reported. The recorded data covers a 24-month range, while the cat - alyst lifetime exceeds this period. Depending on the config - uration, OleMax 100 can be regenerated by coke burn-off. Economic benefits The previous Categories #1-3 add complexity and invest - ment to refinery-petrochemical operations compared to simply using the ROG as a fuel gas source. However, as indicated several times, the safe recovery of valuable com - ponents exceeds the investment and operational costs by far, with a fast return on investment as the required busi - ness case. ROG purification projects have been increasing in volume over time. The average total mixed feed stream amounts to 95 MT/hr per unit over the last 30 years. Table 2 examines Figure 6 OleMax 101 has demonstrated conversion of Ac over a wide range of feed concentrations Component Content, mol% Content, MT/hr Content, MT/yr Ethylene 17.7 9.25 81,000 Propylene 4.1 3.2 28,000 Feed stream 100.0 33.0 289,000 An operational ROG purification system

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Ref H Ref E Ref F Ref G Ref D Ref C Ref B Ref A

! 0

" 5

#" 10 15

$" 25

%" 35

&! 40

Ethylene, mol%

Figure 7 OleMax 101 is used in a wide range of feed sources, as shown by the ethylene content in the select references

Table 2

Gas 2025