Solids formation in a condensate reboiler


A customer operating a natural gas gathering system was finding solids buildup in their condensate processing equipment. This material was depositing in their stabilizer reboiler bundles, impacting system performance. Their condensate specification for receipt from the gathering system is 5-ppm H2S. The condensate is then treated with MEA-triazine to reduce the sulfide level further. It was believed that the local treatment was resulting in a large amount of dithiazine generation, and that by increasing the triazine dosage rate, the formation of dithiazine could be avoided. OndaVia was called in to test the solids and condensate for MEA-triazine and other scavenging residuals.


This problem was complex and multi-level. OndaVia tested the solids collected from the reboiler and verified that dithiazine was present. OndaVia also tested the condensate and found high levels of residual amine and dithiazine. However, when the customer increased the MEA-triazine dosing rate, the level of dithiazine residual did not decrease. This result led the team to investigate further upstream within the gathering system.

Water samples were collected from multiple in-field sump tanks and tested for dithiazine and monoethanolamine. Although most samples showed low scavenging by-products (<100-ppm), two tanks had levels that exceeded 5000-ppm for dithiazine. It was determined that these well-heads were the source of the scavenger by-products found in the reboiler.


By optimizing treatment of these two wells, the customer was able to eliminate the problem. Without testing to determine the source, the customer would have continued to overdose MEA-triazine at a cost of hundreds of dollars per week. Even with this dosage, they were still facing frequent system shutdowns for cleaning and solids removal.

Total savings: >$50,000 per year