PTQ Q2 2025 Issue

Rod Core T @ 300˚C

Rod Core T @ 350˚C

No treatment Dispersant in the low-P multifunctional naphthenic acid corrosion inhibitor (Predator*)

8 10 12 14 16 18

40 50 60 70 80 30 20 10

6 4 2 0

100

150

200

250

Experiment time in minutes

Figure 7 Hot Liquid Process Simulator – naphtha (left) and gas oil hydrotreater (right)

of hydroprocessing and other catalytic units, downstream of corrosion inhibitor injection, from phosphorus and other compounds, are a significant concern and a risk to the refin - ery operability and profitability. Table 1 shows the results of hydrotreater feedstock char - acterisation of ~200 feed samples carried out by Veolia to look into the impact of parameters other than compounds based on phosphorus and metals, on hydrotreater fouling due to a variety of polymerisation/gum formation reac- tions. Hydrotreater reactor bed deposits typically consist of corrosion products, coke particulates, and polymerised materials/gums. The new low-P multifunctional naphthenic acid corro- sion inhibitor contains an improved dispersant for both low- and high-temperature applications for a variety of foulant materials such as corrosion products (iron oxides, iron sulphides, iron phosphates), coke fines, and polymeric materials/gums. This dispersant is an oligomeric surfactant chemistry that is free of phosphorus, sulphur, and metals, and works mainly by steric stabilisation. It has been used for hydrotreater fouling issues in many refineries world - wide for more than 40 years. To test the dispersing performance, an HVGO sample (TAN~1.55; total sulphur ~1.94 wt%) from a US refinery was doped with iron phosphate at 1 wt% phosphorus loading and studied for iron phosphate fouling at 250ºC on carbon steel metallurgy in a static autoclave. The disper - sant of the patent-pending low-P multifunctional corrosion inhibitor exhibited a superior dispersancy than that from the traditional phosphorus and sulphur-based dispersant chemistry, which is commonly used for high-temperature applications. The dispersing/anti-fouling ability of this superior disper- sant was also studied by the Hot Liquid Process Simulator (HLPS), which is a dynamic test ( source: NASA/TM-2012- 217211 8 ). This is an industry-standard test used to measure the differential pressure and/or the differential temperature due to filter plugging or deposition of foulants on the test rod from a laminar flow for a given hydrocarbon fluid over a heated rod at a field-relevant temperature under nitrogen pressure. 9

Samples of naphtha and gasoil, with a general character - isation per Table 1, for a refinery hydrotreater were tested for their fouling potential at 300ºC and 350ºC (572ºF and 662ºF), respectively, by using the HLPS. Differential pressure (dP) across the filter in the heat exchanger outlet was meas - ured for both the untreated test fluid and the one treated with the dispersant of the new low-P multifunctional CI. The dispersant chemistry works by keeping the contaminants/ foulants dispersed and stabilised in the bulk fluid, not allow - ing them to deposit on the test rod or filter, as is seen by the significantly reduced dP over time in Figure 7 . Comprehensive assessment, monitoring, and control approach The effective management of high-acid crude processing and associated chemical treatment protocols necessitates a comprehensive approach encompassing multiple critical elements. This approach requires: • Detailed crude characterisation such as NAN and TAN analysis, sulphur content determination, crude oil finger - printing, and corrosion modelling. • Asset integrity assessment such as metallurgical compo- sition analysis, fluid dynamics evaluation, temperature and pressure monitoring, pipeline configuration assessment, spatial relationship analysis, and shear stress calculations. To help in the analysis of these complex corrosion con- ditions, Veolia has developed and patented the proprietary Predator High-Temperature Corrosion Assessment tool to facilitate systematic risk evaluation through:  Identification of critical impact zones.  Implementation of monitoring protocols chemical injec - tion location.  Baseline conditions and entitlement to develop pro- gramme control, data interpretation, training, documen- tation, and continuous improvement strategies. This integrated approach ensures optimal process efficiency and asset protection in high-acid crude processing operations. Conclusion A new low-P multifunctional naphthenic acid corrosion inhibitor comprised of a primary corrosion inhibitor combined

PTQ Q2 2025