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Tuesday, March 18, 2008 - 4:40 PM
Convention Center, Second Level, R09 (Ernest N. Morial Convention Center)
08649
Development and Field Deployment of a Novel Acidic Triethylene Glycol Buffer Chemical for Bringing Gas Dehydrators Back into Specification
The triethylene glycol (TEG) in the BP Bruce platform glycol dehydrator towers was seen to steadily increase to over pH 10. This rise in pH was found to be attributable to the carry over of triazine based H2S scavenger chemical, used to treat sour process gas. This paper details the root cause failure analysis as well as the various mitigation strategies researched and developed and the final field deployment.
High glycol pH increases the risk of process upsets because it will have an affect on the resultant gas dew point and therefore promotes concern over the hydration efficiency at re-boiler temperatures of close to 200°C. Further potential issues include foaming, regeneration efficacy, solids precipitation and increased scale potential.
The proposed solution was for an acidic buffer chemical to be injected into the glycol to lower the pH. However at the lower pH a possible corrosion problem could result so a detailed laboratory study was undertaken to help risk assess the impact of introducing an acidic chemical in to the system. The study evaluated several potential acidic chemicals and tested for compatibility, corrosivity, solids precipitation, high temperature stability and buffering efficacy.
The paper goes onto detail the risk assessment process used to determine the method and mode of field application as well as the results from the successful field application of this chemical.