Excalibur Shield Introduction: Part 1 of 7
We have produced the best internal pipeline corrosion control program in the world. The Excalibur Shield (US Patent No. 10337979) uses weight loss coupons at representative locations, scientific analysis of liquid and solid sample collection, and custom chemical treatment for a highly effective maintenance program.
Analyzing liquid and solid samples from inside the pipeline for microbially influenced corrosion (MIC), and monitoring weight loss coupons in MPYs (millimeters or thousands of an inch per year) generates the most accurate assessment of the internal pipeline conditions. The result is a customized solution.
Technical Overview: Part 2 of 7
Case Study: Part 3 of 7
In this case study, the Excalibur Shield was employed at a West Texas liquid pipeline system to collect solid samples, chemical residuals, analyze for MIC and monitor weight loss coupons at the worst case scenario on a 20-mile long, 10” carbon steel condensate pipeline operating at 700 PSI with a 50% shut down rate.
The internal pipeline conditions were ideal for bacteria growth and microbially influenced corrosion, and the pipeline system was only being monitored by a retriever style coupon (Figure 1). The pipeline segment was suffering from a lack of internal monitoring, corrosion rate monitoring at the most severe locations, and insufficient solid and liquid sampling and analysis.
The pipeline operator was injecting biocide and corrosion inhibitors with minimal opportunity to monitor the effectiveness, and the chemical treatment testing was only available while the operator used a solid urethane maintenance cleaning pig. The cleaning pig cycles were also not consistent with best practice for monitoring, and there was no coordination between the field pipeline technician and corrosion technician during the pig runs. For example, the corrosion technician was notified weeks after sample collection. The corrosion control program lacked proper corrosion identification, coordination, mechanisms and optimization of chemical treatment programs.
The only effective analysis was the retriever style coupon (Figure 2). The weight loss coupon measured 2” x ¼” in diameter and was installed and exposed to the internal pipeline conditions for 117-days, and resulting in a 0.17 MPY wall loss rate. The corrosion rate of a coupon is expressed in mils per year (MPY), with one mil being the same as one-thousandth of an inch of metal loss inside the pipeline at the coupon surface over a 1-year period.
The localized average corrosion and pitting rates from the coupon are categorized as low, moderate, high, and severe in accordance with NACE classification SP0775-2013 (Table 1). Ideally, coupons are inserted at the 12 o’clock position and lowered to the 6 o’clock position in a horizontal pipeline. The placement of the coupon is the most critical decision in determining the most accurate internal corrosion rate. In this case, only the tip of the coupon was exposed to the worst conditions in the pipeline.
After much discussion, our clients and operators agreed to both a representative location and the most severe location with respect to corrosion. Many operational and environmental conditions influence the optimal selection of location, thus, it is best served when the decision is made by the entire team. We installed the Excalibur Shield at the worst case scenario location, or lowest lying area of the carbon steel condensate 10” pipeline, and again at the end of the 20-mile segment where the pig receiver is at the six o’clock position (Figure 3 and Figure 4).
The Excalibur Shield was easily installed on the existing infrastructure, requiring only 13″ minimum clearance and no welding. The existing sump tank drainage piping system (Figure 3) was used to install additional fittings to accommodate the Excalibur Shield (Figure 4). After installation, we established the capability of acquiring solids, liquids, and monitoring the weight loss coupon at the worst case scenario.
The Excalibur Shield has a primary filtering system at the mouth with a 100-millimeter cavity. The coupon is installed inside this cavity with a secondary filter system surrounding the coupon. The outer portion is octagon shape for easy removal and includes a drain with ventilation valves for easy collection of fluids inside the cavity. The base adapter is outfitted with an O-ring seal for easy removal and secure sealing capability using a 316-L stainless steel body, rated at Maximum Operating Pressure (MOP) of 2000 PSI (Figure 4).
After the first 30-day period of exposure to the internal pipeline conditions, the weight loss coupon registered a 1.28 (MPY) wall loss rate at six o’clock, compared to the 0.17 (MPY) estimated by the previous 117-day exposure using the retriever coupon (Figure 2), mimicking the low lying area in a worst case scenario. We also acquired fresh solid samples (Figure 5) and liquid samples (Figure 7) from inside the pipeline to establish the presence and concentration of bacteria colony counts in milligrams to grams, within the sampling location.
In this case, tests for acid producing bacteria (APB) and sulfate reducing bacteria (SRB) showed very low counts for these organisms. Going forward, our clients now have the capability of collecting fresh liquid and solid samples internal to the pipeline for a more accurate assessment.
After a second 30-day exposure, the optimization of the chemical inhibitor resulted in a 0.08 MPY (Figure 8) loss rate using Excalibur coupon data, a 94-percent reduction in the measured internal corrosion rate. This case study demonstrates the retriever-style coupon and irregular sampling prior to the Excalibur Shield use was insufficient. Fundamental awareness and coordination were lacking and this case study highlighted the need for education at all levels of the corrosion program.
In Summary, acquiring samples at regular intervals, corrosion rate monitoring with coupons in worst-case scenario locations, fluid sampling, solid sampling and inhibitor treatment under the umbrella of the Excalibur Shield provided our client with a vastly improved corrosion monitoring, assessment and control program.
Rather than reacting, we established a proactive and data driven program that vastly improves integrity management and pipeline internal corrosion control. The new wealth of data analysis and coordination between technicians and chemical operators also instilled more confidence in the overall internal pipeline corrosion control program, and the optimized treatment program reduced chemicals costs.
Technical Specifications: Part 4 of 7
Excalibur Shield Components And Measurements
- Filter Cap, Plastic.
- Filter Screen Retainer, Plastic.
- Filter Disc Screen, SS 304, 60 and 100 mesh.
- Filter Cylinder Screen, SS 304 outside 100 mesh with inside support.
- Guard, Plastic.
- Filter Base Adapter, Plastic.
- 316L Stainless Steel, 2000 PSI.
- 1″and 2″ Pipeline Connections.
- 1-to-3 coupon holder.
- 1/2″ NPT Ball Valve.
- 1/4″ NPT Needle Valve.
- 100 ML Cavity.
NACE Presentation: Part 5 of 7
National Association of Corrosion Engineers (NACE) sectional meeting in Midland, Texas featuring Joe Gallo’s presentation on the Excalibur Shield Corrosion Control Program. All Excalibur Shield operations, equipment and materials are monitored yearly for NACE, Veriforce, ISN and Master Evaluator certifications.
Excalibur Customers: Part 6 of 7
New Client Pilot Program: Part 7 of 7
We provide free consulting on all Excalibur Shield Internal Corrosion Control Program activities utilizing our years of experience to ensure you are successful. Support includes education, suggestion locations on pipeline systems, coordination of contractor and maintenance personnel, installation location for better ergonomics, maintenance procedures, analysis and treatment recommendations.