Elimination of Acid Cleaning of High Temperature Salt Water Heat Exchangers
WP-200302
Objective
High temperature heat exchangers scale heavily when operated at wall temperatures above 150°F. Scaling results from the reduced solubility of calcareous salts in high temperature water. Since the hot inlet gas causes high tube-wall temperatures on the seawater side of the heat exchanger, dissolved solids in the seawater coolant precipitate and form calcareous deposits on the tube walls. These deposits corrode and erode the walls, causing cracks and holes that eventually lead to failure. As a result, in-situ and shore-based depot chemical cleaning are required to help prevent corrosion and erosion. These costly and manpower-intensive processes use various cleaning chemicals, such as tri-sodium phosphate, sulfamic acid, and sodium carbonate. Shore-based activities then carry excess hazardous materials in support of these cleaning procedures, and this can generate up to 10,000 gallons of hazardous waste per application. The objective of this project is to eliminate acid cleaning by validating a new design for saltwater heat exchangers.
Technology Description
The project will demonstrate and test a new heat pipe technology in a bleed air heat exchanger (BAHE). This heat exchanger is used on gas turbine-powered ships to cool the gas turbine engine bleed air from 925 to 190°F. To eliminate scaling and the use of hazardous chemicals in main condensers and in the BAHE, a heat pipe (HP) configuration will be substituted for the existing shell-and-tube design. Reproducibility testing and assessments will be conducted, and cost benefit analyses comparing heat pipe coolers to shell and tube coolers are planned.
Benefits
The successful application of this technology will have a large payback through reductions in hazardous wastes, maintenance, and total ownership costs. In selected applications, the implementation of HP heat exchangers will also increase the longevity of the heat exchangers by eliminating scaling that induces corrosion and erosion and eventually failure of the coolers and other downstream components.
Points of Contact
Principal Investigator
Denis Colahan
Naval Sea Systems Command (NAVSEA)
Phone: 215-897-7231
Fax: 215-897-7564
Document Types
- Fact Sheet - Brief project summary with links to related documents and points of contact.
- Final Report - Comprehensive report for every completed SERDP and ESTCP project that contains all technical results.
- Cost & Performance Report - Overview of ESTCP demonstration activities, results, and conclusions, standardized to facilitate implementation decisions.
- Technical Report - Additional interim reports, laboratory reports, demonstration reports, and technology survey reports.
- Guidance - Instructional information on technical topics such as protocols and user’s guides.
- Workshop Report - Summary of workshop discussion and findings.
- Multimedia - On demand videos, animations, and webcasts highlighting featured initiatives or technologies.
- Model/Software - Computer programs and applications available for download.
- Database - Digitally organized collection of data available to search and access.