30 Years of Scrubber Installations – the Lessons We Must Learn!

According to an American Bureau of Shipping article written by ABS manager, Alex Hugo, despite scrubbers being in the industry for long many don’t the lessons learnt from this technology, ABS is seeking to change that.

Lessons from experienced scrubber users are important

At the beginning of this year, the IMO’s global sulfur cap on marine fuels entered into force and shipowners who chose the SOx -scrubber pathway to compliance began the modern era of emissions reduction.

Scrubbers have been operating in marine environments for almost 30 years, so owners were not exactly entering a brave new world of technology. But any time a new technology is integra­ted into an individ­ual vessel’s operating system, lessons are learned; and these lessons create a knowledge base that operators with less experience with scrubbers can draw from.

• Leading class societies have been supporting scrubber integration in the marine environment since their first application.
• ABS, for one, has gathered the depth of market intelligence required to help owners to improve the process of installing and operating most scrubber systems.
• Lessons have been learned about everything from installation and commissioning to the most common hardware failures for operating systems, and the type of consumables that are typically needed.
• In this post, we will discuss some of the key issues associated with the installation and operation of scrubbers.
• But for a comprehensive list, please download ABS’s guide, Practical Considerations for the Installation and Operation of Exhaust Gas Cleaning Systems.

An approved test plan to counter problems

In commissioning SOx Scrubber systems, there can be challenges associated with extensive test periods, usually the result of an owner/operator having limited test plans and/or pre-commis­sioning work. This may be relatively intuitive, but following an approved test plan and completing the pre-commissioning activities are the fastest way to avoid these problems.

Washwater Carried Over

Another recurrent problem we are seeing, specifically during the installation process, is when wash­water is carried over with the exhaust gas.

This is commonly the result of unsuitable or inefficient flowpaths for the exhaust gas and can be resolved by optimizing the flowpath and/or modifying the design of the demister, which removes liquid droplets from the vapor stream.

• In one recent event, a main engine stalled due to high backpressure after a scrubber by-pass damper failed to open when the scrubber uptake damper was closing.
• The programmable logic controller that was designed to control the interlock of the by-pass and uptake dampers had failed. Regular mainten­ance and testing in accordance with manufacturer’s instructions could have identified the problem.

The incident made clear that safety features require regular maintenance and testing in accord­ance with the manufacturer’s instructions,

and that crews in charge of any system need to be familiar with basic starting procedures, such as checking damper positions and safety features.

In general, the industry has learned a lot about exhaust-gas scrubbers in the 30 years since they were first used in marine applications. The average owner may have become relatively familiar with the indivi­dual systems they chose to use.

However, leading class societies such as ABS will have learned the lessons from many sys­tems, and have the depth of knowledge to help owners with any challenges they may face.