OVERVIEW: The ammonia lines had been in service since the plant was built. This has caused severe external corrosion caused holes to form in the pipe and there were no spare lines for the plant to be shutdown. Very expensive pipe sealing clamps were in use and the condition of the rest of the pipelines were deteriorating rapidly as the pipes are constantly cold and very wet. Engineers had put corrosion protection of the pipes in abeyance which was just exacerbating the problem.
ENVIRONMENT
Ammonia Pipeline externals
SUBSTRATE
Steel Substrate
CHALLENGE
The ammonia lines had been in service since the plant was built. This has caused severe external corrosion caused holes to form in the pipe and there were no spare lines for the plant to be shutdown. Very expensive pipe sealing clamps were in use and the condition of the rest of the pipelines were deteriorating rapidly as the pipes are constantly cold and very wet. Engineers had put corrosion protection of the pipes in abeyance which was just exacerbating the problem.
SOLUTION
Moisture-Tolerant and Solvent-Free epoxies RS 500P and RA 500M were recommended as this system requires minimum surface preparation (i.e. no dry grit blasting) and solvent-based materials were not allowed. These epoxies are ideal for confined spaces.
Rain, water, condensation or high humidity has no effect on freshly painted surfaces and its environmentally friendly properties allowed work to continue throughout the Queensland Wet Season. Areas were high-pressure washed at 500bar to a WJ4 standard. Coating was applied to an average DFT of 300µm.
PRODUCTS
OUTCOME
This coating system is relatively new to Australia and is a prime example of innovative technology being used to save the existing plant from the possibility of catastrophic failure. Despite the extreme weather experienced in Queensland and the complex layout, the coating work was finished on time and within budget. As a result, there will be considerable savings in the cost of pipe sealing clamps in the future and improvement in plant safety has exceeded the engineer’s expectations.
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