Ammonia (NH3) is one of the most highly produced inorganic, synthetic chemicals & is critical in manufacturing fertilizers. There are numerous large-scale ammonia production plants available worldwide and, as per the 2016 report, produced a total of 144 million tonnes of nitrogen. In addition, there are numerous critical applications used in ammonia plants, need specialty lubricants to run the machine. However, today’s effort is to address investigating lubricant failures on Ammonia plants.
How to Define Lubricant’s Failure in Ammonia Plants?
A lubricant’s function and characteristics must be understood before its failure can be analyzed.
Lubricants can fail in numerous ways:
- Thermal breakdown,
- Micro dieseling,
- Additive depletion,
- Or electrostatic spark discharge.
However, with each failure mode, there are associated conditions (such as temperature or contaminants) and outcomes (for example, tar deposits, coke, or sludge) that can aid in the identification of the failure mode. The outcomes or deposits are essential in determining how a lubricant degraded if a root cause analysis was performed for that component.
Additionally, oil analysis tests can be done to recognize failure modes either before or after the failure. While there are many oil analysis detection methods, not all can be carried out on a single component. Therefore, there must be a strategic selection of oil analysis tests that can form a baseline suite that will enable end-users to identify and possibly rectify issues in the lubricant before it fails. From the research conducted, it can be deduced that a primary suite of tests should include; Linear Sweep Voltammetry (Remaining Useful Life Evaluation Routine), Acid Number, Fourier Transform Infrared, Viscosity, Quantitative Spectrophotometric Analysis / Membrane Patch Calorimetry / Ultra Centrifuge, and Rotating Pressure Vessel Oxidation Test. These can aid in identifying the type of degradation and can be used in the root cause analysis to determine corrective actions to avoid future failures.
Root Cause Analysis of a Lubricant Failure:
It has been determined that while root cause analysis is a powerful tool, it is not always applied correctly when investigating lubrication failures. The five phases of data collection, assessment, corrective actions, informing, and follow-up are quintessential stages that must be adhered to during an investigation to identify the reasons for a lubricant failure. The first two stages of data collection and assessment form the basis for determining the reason/s for failure. As such, close attention to areas of data collection such as the lubricants, filters and separators, deposits, oil analysis tests, sump conditions, lubrication system, and system parameters must be observed during the investigation. Similarly, verifications of insufficient or excessive lubricant volume, wrong or contaminated lubricant, lubricant failure, and abnormal wear debris generations must be examined thoroughly during the assessment stage. It is believed that if industrial plants properly employ root cause analysis, then there will be a marked decrease in failures.
How to Reduce Machine Downtime Cost due to Lubricants Failure:
Any failure within industrial plants leads to unplanned downtime, which incurs a cost to the organization. These costs are significantly high, and methods to avoid these are usually employed. However, if proper condition monitoring techniques such as oil analysis are not adequately applied in the appropriate frequencies, failures can occur without sufficient warning. If root cause analyses are also not conducted, then the failures become repetitive and are never solved. It has been found that with ammonia plants, some of the basic suites of tests are not adequate to identify impending failures.
The deposits formed in most ammonia plants typically consist of primary amides, carboxylic acids, and ammonium salts. Therefore, to identify the onset of a typical lubrication failure for an ammonia plant, the user should test for the presence of carboxylic acids and monitor the condition of the lubricant in service with the use of Viscosity, Acid Number, Membrane Patch Calorimetry, Remaining Useful Life Evaluation Routine, Rotating Pressure Vessel Oxidation and Fourier Transform Infrared tests.
Suppose the service of chemical filtration is available to the end-user. In that case, this should be employed to remove the carboxylic acids from the lubricant since these initiate the reaction with ammonia to produce varnish or sludge within the system.
Root cause analysis is imperative to identify the reasons for lubrication failures, and these should be performed before assigning blame to ammonia gas/liquid in a system.
You can also read below articles for more information.
What is Tribology, Tribosystem & Lubrication
Basics of Industrial Lubricants.
Lubricating Oils Vs Lubricating Greases | What to Choose & Why?
Sanya is the Founder of Strategic Reliability Solutions Ltd based in Trinidad and operates in the capacity of Managing Director and Senior Consultant. She works with global affiliates in the areas of Reliability and Asset Management to bring these specialty niches to her clients.
Sanya possesses a strong engineering background with a BSc in Electrical & Computer Engineering and MSc in Engineering Asset Management. After completion of her thesis “An investigation into the root causes of lubricant degradation in critical equipment in an Ammonia complex”, she was made aware of the plight that reliability faces within and outside of the Caribbean. As such, she decided to ensure that every attempt was made to make reliability the backbone upon which the industry operates by forming Strategic Reliability Solutions Ltd.
Sanya has worked in the lubrication industry for the past several years and has used her engineering background to assist various industries with lubrication related issues both locally in Trinidad and Tobago, regionally and internationally. She has solved lubrication problems and provided training in the Automotive, Industrial, Marine, Construction and Transportation sectors.