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Case Study

ChemLINE® 784Spent Sulfuric Acid (H2SO4)Rail Fleet — Tank Cars

APC Offers Tailored In-House Testing: ChemLINE® 14 Weeks Spent H2SO4 Immersion Report

A major North American environmental services company needed assurance that ChemLINE® coatings could withstand spent sulfuric acid (H2SO4) in railcar transport. APC ran a tailored in-house immersion study across two tank sources and two coating systems, with no blistering, cracking, or delamination observed.

14 wks
Longest immersion duration (PT-WW)
279 days
ChemLINE® 784 immersion duration
2
Tank sources tested separately
0
Blistering, cracking, or delamination

Summary

Aggressive spent acid, with no certainty the source tanks matched.

A major environmental services company in North America needed to confirm their coatings could reliably protect railcars transporting spent sulfuric acid (H2SO4, CAS 7664-93-9). Four bottles of spent sulfuric acid were supplied, labeled Tank 1 and Tank 3; all black in color in liquid form.

Since it wasn't known whether there were differences between Tank 1 and Tank 3, APC tested both separately to ensure comprehensive, tailored results rather than assuming uniformity across the supply.

Test Method

Two coating systems, two tank sources, immersed at customer-specified conditions.

2"×5" samples of ChemLINE® 784 and ChemLINE® PT-WW were sprayed and cured per APC specifications at 122°C for 6 hours. Samples were immersed at 40°C, per the customer's request, with Tank 1 and Tank 3 solutions evaluated independently for each coating system.

ChemLINE® 784 samples were monitored over a 279-day immersion period; ChemLINE® PT-WW samples were monitored over a 92-day period, with weight change and visual condition tracked at regular intervals throughout.

  • Substrate 2"×5" steel test panels
  • Coatings tested ChemLINE® 784/32 (Grey) and ChemLINE® PT-WW
  • Cure 122°C / 6 hours
  • Test medium Spent sulfuric acid (H2SO4), CAS 7664-93-9
  • Tank sources Tank 1 and Tank 3, tested separately
  • Temperature 40°C, per customer request
  • Monitoring Weight change + visual inspection through 279 days (784) / 92 days (PT-WW)

Results

Stabilized weight change, coatings held integrity throughout.

Weight change stabilized within the test period for both coating systems and both tank sources. Visually, all samples appeared in excellent condition despite the varying shades of grey and discoloration typical of sulfuric acid exposure in the liquid phase.

The vapor-phase portion of each panel remained semi-gloss throughout testing, with no signs of blistering, cracking, or delamination observed across either coating system or tank source.

  • Weight change stabilized within the test period for both coatings
  • No blistering, cracking, or delamination observed
  • Vapor-phase surface remained semi-gloss throughout
  • Consistent performance across both Tank 1 and Tank 3 sources

Conclusion

Tailored testing builds customer confidence in aggressive rail service.

This study showcases the effectiveness of Advanced Polymer Coatings' tailored in-house testing services. By evaluating coatings against the customer's actual spent acid supply, rather than a generic reference standard, APC ensures its coatings meet the highest performance and durability standards for the specific service in question.

This accelerated testing has given the customer confidence that ChemLINE® 784 is the right choice for protecting their railcars from aggressive spent sulfuric acid service.