(118a) Water Treatment for TLE's - Most Effective Technology

This presentation will provide a review of current technology choices for the effective treatment of the water and steam circuits in ethylene furnace transfer line exchangers (TLE) to insure optimum reliability, longevity and efficiency. We will briefly review major TLE designs, as well as the operational issues and recommended best practices for both cold start-up and furnace decoke procedures. External treatment processes, including demineralization and condensate polishing, will be reviewed from the perspective of minimizing contaminant ingress. Current boiler water treatment practices will also be critically reviewed with respect to ASME and VGB application guidelines. This will include a discussion of the choices and selection criteria for oxygen scavengers, as well as an experience-based review of the major internal treatment chemistries, including coordinated/congruent pH/phosphate control, alkaline phosphate and all-volatile treatment. The application and benefits of synthetic polymeric dispersants in TLE's will also be discussed. Steam/condensate treatment technology based on volatile alkalizing agents will also be reviewed, along with steam purity guidelines and issues as they relate to steam turbine reliability and integrity. Finally, there will be brief case history review that will highlight several of the key discussion points.