Page 22: of Maritime Reporter Magazine (September 2015)

EMISSIONS UPDATE the system will eventually stop scrub- The Hybrid Design is also archived in the CEM panel along of ethics. EGCSA member companies bing. To avoid that excessive buildup, a A hybrid design is a combination of an with the wash-water monitoring data work very hard at maintaining a high closed loop system incorporates a small open lop and a closed loop system. As (PAH, pH and turbidity) and the ship standard of design and reputable sales continuous bleed (a slip stream) from the such a hybrid scrubber will be the most GPS. and marketing approach. Additionally circulation loop. That stream is continu- expensive but the most ? exible solution. they are supporting the shipping indus- ously replaced by fresh water to keep the A hybrid system will have all the addi- Water Monitoring Equipment try in working with IMO in clarifying system in balance. Additional fresh wa- tional equipment associate with a closed Per the IMO guideline for exhaust and simplifying some of IMO’s require- ter is also added to replace the water that loop system but will also circulate more gas cleaning systems, the ef? uent water ments. is evaporated by contact with the hot ex- water and be constructed of higher grade from the scrubber shall be monitored for All EGCSA member companies have haust gas. Since the untreated discharge alloys as the open loop system (because pH, turbidity, and PAH. The data col- presently provided scrubbers to the ship- water from a closed loop system has of the use of seawater in open loop op- lected by these sensors is displayed on ping industry and have had signi? cant much higher pollutant content due to the eration). the wash-water monitoring control panel successes. As an example, CR Ocean normal build-up that occurs in the closed The advantage of a hybrid system is screen and is also archived on the CEM Engineering (CROE) has several on circulation, additional water cleaning that it can be switched from open loop to control panel. Since IMO has set the tur- board units in successful operation and equipment is required prior to discharge closed loop operation on command. One bidity and PAH as increased levels from many others in the design and fabri- at sea. The typical water cleaning equip- can operate in closed loop mode when the normal surrounding waters, it may cation stage for some very reputable ment used in closed loop operation is a in port of fresh water and then switch to be a good precaution to install turbidity shipping/cruising companies. Having centrifuge or some type of positive ? ltra- open loop when in open seas. This will and PAH monitors on the water intake as had more than 60 years of successful tion. As with the open loop system, the minimize the amount of caustic used and well as the water discharge points to bet- scrubbing systems design under its belt, closed loop system will also include all in long run save operating money. Each ter de? ne the differential between inlet CROE’s success in the marine industry monitoring and control equipment. Ad- ship with a hybrid scrubber installation and outlet. This may be very useful in started with it’s ? rst installations on a ditionally, it will require caustic storage will be able to optimize their operation proving compliance even when the nor- Great Lakes bulk carrier. and feed system as well as purge water based on route and local port state re- mal water intake levels of turbidity and The moral of the story is that scrub- storage tank if desired. One major ad- quirements. PAH exceed the required IMO estab- bing systems can save signi? cant money vantage of a closed loop system is that lished values. if a ship operates in an ECA for more is can be constructed of typical stain- Stack Monitoring Equipment than about 40 % of the time. Risks can less materials because the pH levels are The stack emissions are monitored by Conclusion be managed by contracting with a known easily controlled by caustic. Of course a Continuous Emission Monitoring sys- Scrubbers work. Many scrubbers are and reputable company with proven chloride levels may affect the ability to tem (CEM). The CEM sensor is located now in operation and many others in de- scrubbing system design experience (us- use stainless steel materials and there- in the stack above the scrubber unit. The sign and installation phases. Because ing EGCSA member companies is one fore a proper review of the water and CEM unit will measure SO2 and CO2. of this initial problem some suppliers, way to minimize risk). In the end all caustic used is required to make sure that The emission data collected by this unit the Exhaust Gas Cleaning Systems As- parties want a successful system opera- the maximum chloride levels are not ex- is displayed on the CEM control panel sociation (EGCSA) was established and tion for many decades and all can bene? t ceeded in the circulating solution. screen. The exhaust gas emission data all members vowed to a very strict code by this IMO established equivalency.

DESIGN

ASSESSED 22 Maritime Reporter & Engineering News • SEPTEMBER 2015

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