As the maritime industry focuses on reducing emissions and complying with IMO 2020 regulations, marine scrubbers have become essential for ships using high-sulfur fuels. Two main types dominate the industry: Close Loop Marine Scrubbers and Open Loop Marine Scrubbers. Understanding their key differences, advantages, and regulatory implications helps shipowners make an informed decision for their fleet. When comparing Close Loop Marine Scrubber vs. Open Loop Marine Scrubbers
Close Loop Marine Scrubber vs. Open Loop Marine Scrubber: Key Differences, also known as Exhaust Gas Cleaning Systems (EGCS), remove sulfur oxides (SOx) from ship exhaust gases. They allow vessels to continue using high-sulfur fuel oil (HSFO) while meeting emission standards.
There are two primary scrubber types:
✔ Close Loop Scrubber – Uses a recirculating water system.
✔ Open Loop Scrubber – Uses seawater intake and discharge.
Each system has unique operational, environmental, and regulatory advantages.
Key Differences Between Close Loop and Open Loop Marine Scrubbers
1. Operational Process
✔ Close Loop Scrubber: Uses freshwater with an alkaline additive (e.g., sodium hydroxide) to neutralize SOx. The treated water is partially recycled, reducing seawater discharge.
✔ Open Loop Scrubber: Uses seawater to wash SOx from exhaust gases and discharges it back into the ocean after treatment.
Close Loop Marine Scrubber vs. Open Loop Marine Scrubber: Key Differences
2. Environmental Impact
✔ Close Loop Scrubber: Produces less wastewater discharge, making it ideal for use in restricted areas.
✔ Open Loop Scrubber: Can discharge sulfur-treated water into the sea, leading to potential environmental concerns.
3. Compliance with IMO Regulations
✔ Close Loop Scrubber: Accepted in most Emission Control Areas (ECAs) where open-loop systems are banned.
✔ Open Loop Scrubber: Restricted in many coastal waters due to seawater discharge regulations.
4. Cost and Maintenance
✔ Close Loop Scrubber: Higher upfront cost, but long-term compliance advantages. Requires more maintenancedue to water treatment systems.
✔ Open Loop Scrubber: Lower initial investment, but increasing regulatory restrictions may lead to future retrofitting costs.
Which Marine Scrubber System Should You Choose?
For Global Compliance and Long-Term Use
Best choice: ✅ Close Loop Marine Scrubber
✔ Meets strict IMO regulations in ECAs.
✔ Reduces wastewater discharge concerns.
✔ Suitable for long-term investment in emission control.
For Lower Initial Costs and Unrestricted Waters
Best choice: ✅ Open Loop Marine Scrubber
✔ Cost-effective for ships operating in open waters.
✔ Lower installation and operational costs.
✔ Ideal for routes without open-loop restrictions.
Conclusion
Choosing between Close Loop and Open Loop Marine Scrubbers depends on operational regions, budget, and long-term compliance needs. Close loop scrubbers are better for restricted zones and future-proofing against environmental regulations, while open loop scrubbers offer a cost-effective short-term solution for vessels operating in permissible waters.
By understanding these key differences, shipowners can make the best decision to ensure regulatory compliance, environmental responsibility, and operational efficiency.