This article was originally published in Paper Advance.
Workplace safety and profitability are two fundamental values of any organization. If not carefully managed, corrosion of rotating and fixed equipment in a process can seriously compromise both values, whether at pulp mills or other manufacturing and chemical processing facilities.
To better manage failures of equipment and ensure the safety and reliability of the fixed and rotating equipment, efficient inspection practises and proper material selection are key. Failure to do one or both may result in an unsafe working environment and in significant negative financial impact due to lost production. FPInnovations’ corrosion research program has developed improvement and maintenance tools and expertise to help mills ensure the reliability of their equipment and make the most effective use of their maintenance and capital budgets.
Safety and financial repercussions of planned and unplanned shutdowns
Unexpected outages to address equipment failures are costly, as equipment, supplies, and expertise needed to facilitate repairs must be expedited to the site. They also generate health and safety concerns due to carrying out rushed, non-routine maintenance, and may put employees in hazardous environments.
These outages usually range from 3 to 28 days where the loss of production can result in over $1M per day in lost revenue for a 1000 t/d kraft mill. To avoid this, mills schedule 5-10 day shutdowns for major maintenance on a regular basis; typically every 12 to 18 months for a kraft mill.
In the short period of time available, plant engineers must identify and repair all deficiencies that might cause an unscheduled outage in the following operating period. Planning is almost entirely based on past experience because all resources, equipment and supplies needed to make repairs have to be arranged for months in advance of the shutdown. But, what if a change in process conditions caused a new problem? Are new materials available that could last twice as long in the same service?
Insight from subject matter experts -such as FPInnovations- can define the capabilities of non-destructive testing, improved material selection, and interpret failure analysis results to refine inspection intervals and optimize tasks at an outage.
To optimize the number of tasks at a major outage, effective material selection and applying industry best practices are crucial. Managing or eliminating corrosion mechanisms through material selection can minimize or eliminate repetitive tasks that are performed at every major outage. On the other hand, incorrect material selection can result in premature failure of equipment which could cost well over $0.5M per year in repairs in medium-sized critical and non-critical assets and loss of efficiency and, in some cases, result in lost revenue from green power sales – which could be in the order of millions of dollars per year.
FPInnovations works with mill engineers to demonstrate the impact of changing process variables as it relates to corrosion, with the goal of increasing available production hours. The Corrosion and Materials research has been a cornerstone at FPInnovations since the 1950s, and their expertise has been delivered to mills and plants around the world. The corrosion group offers the following services to help mills improve the reliability of their equipment:
- Corrosion coupon testing: Provide data generated from real world environments to help engineers make decisions about materials for repair or replacement. FPInnovations can plan and execute a program of coupon testing in the mill. Coupons are characterized for corrosion, and evaluated and ranked for best performance. This information allows mill engineers to make informed capital purchasing and design decisions.
- Laboratory testing: FPInnovations maintains a laboratory capable of simulating most environments within a pulp mill. When a decision is needed quickly, electrochemical testing can help make informed material selection decisions, and better understand the impacts of process conditions on material performance. This testing technique is also used for demonstrating credible corrosion mechanism in new and emerging technologies as FPInnovations support mills in their transition to the bioeconomy.
- High temperature testing: FPInnovations has world-class facilities for corrosion coupon testing in a range of chemical environments at up to 1,500 ⁰C. The work at FPInnovations helps the industry push the boundaries in boiler efficiency and biomass-based power and has addressed high temperature damage mechanisms that previously represented high-risk areas in both chemical recovery and power boilers.
- Risk-based inspection: Maintenance budgets are often spread too thinly by calendar-based inspection practises that require the performance of too many tasks at major outages. In other cases, engineers may not have a means of prioritizing maintenance tasks across all assets at the mill. A risk-based approach allows a mill to focus maintenance budgets on critical assets that represent the most risk. FPInnovations can help mills develop a 5-to-10- year road map to manage risk exposure using focused inspection practises and engineering initiatives.
Safety and profitability of any organization is key. Proper corrosion management means reliable machinery, and a reliable mill is a safe and profitable mill.