Forney Best Practices for Igniters used by AEP-Forney Team to Sustain High Reliability
At the AEP-BRO Forum 2015, AEP’s Oklaunion Plant presented findings of a recent project that studied degradation in reliability of 32 Forney DURAFire® Class 1 oil igniters. AEP’s BRO (Boiler and plant Reliability Optimization) Forum is an annual event held in Columbus, Ohio, where AEP plant personnel, utility company guests and top industry suppliers gather to discuss issues affecting boiler and plant reliability.
The logbooks of AEP’s Oklaunion plant (a 720 MW coal fired unit in Vernon, TX), showed that igniter problems on a burner deck occurred 50.4% of the time when placing a coal mill in and out of service leading to an increased fuel oil consumption of over 70,000 gallons per year. The plant formed a multi-discipline networking team including Forney engineers in November 2014, that applied a Lean Structured Problem Solving (SPS) process to identify potential solutions to these igniter issues.
The problem solving approach was based on the PDCA (Plan-Do-Check-Adjust) model identifying specific actions, checks, and adjustments to be carried out before scheduled outages. As part of the multi-discipline SPS team, Forney engineers met with the plant personnel to explain the igniter parts assembly and operations. This training included identifying best air and fuel settings and troubleshooting spray tips. Based on this training and recommendations, a troubleshooting guide was put in place shortly thereafter. These steps were key in the “do” list of the PDCA model wherein root causes analysis and countermeasures were identified and compiled. The SPS team identified 13 “Just Do Its” for implementation prior to the upcoming outage. Some initial specific “do” tasks involved:-
Following the implementation for the set of corrective “do” measures, the system reliability was found to be 100%. However, these improvements were short lived and soon the reliability degraded back to 50%. Forney and plant personnel did further root cause analysis to identify additional adjustments and countermeasures. This resulted in revising the logic for the atomizer air pressure control valve by changing the opening from 100% to 60% which reduced igniter flame loss due to over-pressure. It was also identified that the ceramic insulators in many of the tips were broken or had cracks from being dropped on the burner deck during maintenance, and this caused malfunctions in the spark tips which required replacement. Other changes implemented included checking air flow on scanner fans, verifying the time sequence on oil valves, and performing bi-weekly preventive maintenance on the igniters. As shown below, the SPS “adjust” follow-up, concluded in January, 2015, was highly successful with igniter reliability remaining at nearly 99% since then.
The collaborative multidisciplinary partnership between AEP and Forney was able to successfully address the igniter reliability concerns within a few months and improved plant efficiency.