Chemically Bonded Porcelain Enamel Coated Pipe for Corrosion Protection and Flow Efficiency

Main Objective

This study will explore, develop, and demonstrate electrostatically-applied, chemically-bonded, dense and consistent enamel powder coating for improved corrosion resistance and durability, reduced surface roughness and pressure loss, and increased bond strength of underground steel pipes under combined external pressure, thermal effect, and internal pressure. Expected outcomes can not only address corrosion related safety issues, but also reduce operation cost in hazardous liquid and natural gas pipelines.

Public Abstract

The U.S. hazardous liquid and natural gas transmission pipelines have reached approximately 2.5 million miles. Despite stringent requirements to ensure safety, approximately 600 incidents occur every year and corrosion is one of the main causes. Overall, corrosion has caused a loss of over $12 billions per year. Thus, the overarching goal of this study is to improve the corrosion protection and safety, and reduce the pressure loss and operation cost of hazardous liquid and natural gas pipelines. To achieve the goal, this study aims to 1) explore and develop chemically-bonded enamel powder coating (100~150 μm) for corrosion protection and safety of metallic pipelines, and 2) develop and demonstrate a rapid field-applicable coating process for flow efficiency and cost reduction in the operation of metallic pipelines. The two objectives will be met by optimizing a mix of three commercial enamels for durability and thermal compatibility, by developing an automated spraying and heating process of coating for thickness consistency and surface roughness, by characterizing the porosity, bond strength, and corrosion resistance of enamel-coated specimens, and by evaluating the stress distribution and stress corrosion cracking of in-situ enamel-coated pipelines.
The chemically-bonded enamel coating applied with this electrostatic spraying and induction heating process has smooth surface for flow efficiency, protects metallic pipelines from corrosion in their life span, and restrains pitting corrosion into a locally breached coating area in the event of unexpected damage.