Specifying emissions monitoring for scrubbers

25th January 2017 | Technology

Simon Brown, managing director of Emsys Maritime provides some handy guidance on the important factors to consider when specifying emissions monitoring technology.


Get your requirements correct at the start. There are many factors to consider when specifying an emissions monitoring system, the most important being the application. Is it monitoring a scrubber? Selective Catalytic Reducer (SCR)? Diesel engines? Boilers? Incinerators? Are there specific IMO, EPA, or local regulations that the EMS must be Type Approved for? Are there Class Notation requirements? How many stacks need monitoring? Which gases do you need to monitor? Is continuous monitoring required? What are the environmental conditions where the system will be installed? Are there extreme temperatures or aggressive conditions at the sample point?


Consideration regarding the positioning of the sample points and where the control panels will be sited is paramount. The positioning of probes, especially in applications such as scrubbers can be the most important consideration. Ensure that the probes do not become contaminated by scrubber washwater, sootblowing or turbocharger cleaning materials. Can the control panel and analysis equipment operate in +55o C ambient? Can the operators get easy access to each part of the system for maintenance? Is it easy to calibrate?


To ensure the EMS system fully meets the requirements, I would recommend 2 key actions; a) Attend the factory Acceptance Test (FAT) and see the system assembled before it is installed. Speaking with the EMS system designers, project engineers and technicians at this stage may bring up some items that may not have been considered at the requirements stage, this may allow time to mitigate any issues that may arise. b) Prepare a detailed on-board test plan to check the system performs to specification. This may identify issues that arise post installation. The on-board testing needs to be carefully planned to ensure each engine, boiler and other stack are available, the loadings are correct, the correct calibration gas is available to ensure the systems are calibrated correctly and the measured data correlates with the anticipated performance data supplied by the engine/boiler/scrubber supplier.

Operating Costs

This is a very important when specifying EMS systems. Shipbuilders have different selection criteria to the shipowner. Operating costs are not the most important factor (usually capital cost and ease of installation) however, this may mean you end up with a system that’s more expensive to operate. Some CEMs based systems are extremely complex. They have many parts, pumps, peristaltic tubes, NOx converters etc.… the cost of spares should be factored into the overall through-life cost equation.


Every emissions monitoring system needs to be maintained. The marine monitoring application is extremely arduous and the environmental conditions for sampling can be highly aggressive to the measurement equipment. As mentioned previously, access to the equipment should be easy, trying to change filters whilst holding on to a ladder is not sensible. The maintenance required by the ship’s crew needs to be well documented and relatively straightforward. Complex analytical systems that need regular servicing by specialist technicians should not be considered.

Maritime Focus

Ensure your supplier is a maritime focused organisation. As the market for EMS has grown, a number of new players have entered the market. These companies may already be supplying CEMs technology to land-based applications and see the marine EMS opportunity as a new potential market. Ensure your supplier has a detailed understanding of the maritime environment,vessel operational considerations and the level of support you expect.


Probably the most important consideration of all given ships crews are regularly changed. A single training session at commissioning is not usually sufficient. If your crew aren’t confident in the system operation, it’s likely they will not take ownership of the system. Training is an expensive and time-consuming factor, however, the reality is you can’t afford to ignore this most important aspect.

Taking time at the outset to prepare a detailed EMS specification based upon your actual application and vessel operational considerations is vital. Don’t just consider capital cost, we all remember the inkjet printer strategy of low upfront cost but back end loaded profit in the cartridges. A well-specified system will be reliable and cost-effective, a poorly specified EMS can become a significant burden to the ship’s crew and end up costing more than the system capital outlay if you have to switch to MGO while waiting for parts or service.

Kindly published by courtesy of Riviera Maritime Media Ltd (Marine propulsion & Auxiliary Machinery 24.01.2017)

Link to original article HERE