Erosion with Boronized Coatings
Personnel
| Chevron | TU PI's | Students |
|---|---|---|
| Sandra Hernandez | Hadi Arabnejad | Austin Prescott |
| Reza Sarrafi | Siamack Shirazi | |
| Michael Keller | ||
| Erin Iski |
Abstract
Heavy oil production and oil sand processing are associated with severe damage and failures of production equipment components including piping systems. Sand erosion and erosion-corrosion may result in significant losses dealing with production downtime, high maintenance and replacement cost, curtailing the production operation process, as well as environmental impact. In order to minimize these problems, proper material selection and the use of protective coatings on piping and valves, which are mainly fabricated from bare carbon- and low-alloy steels, is considered as an effective route to increase the equipment performance.
In the present work, hard boronized coating on carbon steel, obtained through thermal diffusion process, is evaluated. The boronized carbon steel consists of a dual iron boride layer (FeB-Fe2B) with a total layer thickness of 200-250 µm. The material is studied using laboratory tests in dry and wet sand erosion and in an environment with erosion-corrosion conditions and is compared with bare carbon steel and 316 stainless steel. The selected test conditions simulate various oil production operating environments (e.g. dry erosion, liquid erosion, liquid-gas corrosion and synergistic erosion-corrosion at elevated pressures, temperatures and flow velocities). Structural examinations of the surfaces of the boronized carbon steel test specimens after the erosion and erosion-corrosion experiments have been conducted. The iron boride coating demonstrated better performance in dry and wet (non-corrosive) erosion environment compared to bare carbon steel and 316L materials due to high hardness (about 10 times greater than of bare steel). When tested under severe CO2 corrosion concurrent with sand erosion, the boronized carbon steel is observed to over perform carbon steel by almost 1 order of magnitude because of high chemical inertness, and diffusion-related bonding with the substrate. However, it underperforms relative to 316 stainless steel. The boronized steel tubing and casing with inner or inner and outer protection can be effectively employed for a wide range of critical conditions in the oil production unless the environment includes concurrently highly erosive and highly corrosive conditions.