OPEN LOOP SCRUBBERS
Open loop system은 천연 알칼리성을 갖는 해수 100%를 scrubber내부로 통과하는 배기가스에 직접 분사하여 화학작용을 통해 배기가스 중에 황산화물과 입자상 물질을 저감시키고 세정 후 스크러버를 통해 나오는 해수는 PH 농도를 조절 한 후 선외로 배출하는 방식이다.
Open loop system의 특징
- 선외에서 유입한 Sea water 를 wash water로 사용함
- Sea water 에 별도의 NaOH 주입이 필요 할 수 있음
- Sea water pump 외에 추가 작업이 거의 필요하지 않고, 시스템 구성이 간단하다
- Zero Discharge Zone 에서는 사용이 불가한 단점이 있음
Instead of being re-used, the process water is discharged directly back to sea while complying fully to the IMO regulations. Optionally the seawater can be pumped through a water treatment system to remove all solids and oil. Detailed information can be found in our brochure.
How does it work?
- The seawater (process water) is NOT re-circulated but discharged back to sea.
- The sulphur in the exhaust gases dissolves in the process water.
- The process water is pumped through a water treatment system and discharged back to sea.
- Solids and oil from the process water are led to the separator.
- This separator will separate solids and oil from the process water.
- The remaining sludge is pumped to the sludge storage tank on the ship.
- The process water removed from solids and oil will be discharged back to sea.
- The pH, turbidity and concentration of PAH are constantly measured in accordance with MARPOL Annex VI resolution MEPC.184 (59).
- The clean exhaust gases exit the scrubber, removed from sulphur and particles, through a demister.
CLOSED LOOP SCRUBBERS
Closed loop system은 주로 선박 내 청수를 scrubber로 분사하여 황-화합물을 저감시키는 타입으로 분사 후 배출되는 wash water는 NaOH(Caustic soda) chemical 을 추가하여 세전 후 재순환하여 사용한다. 순환시 배기가스 세정에 사용된 Fresh water는 sea water 를 이용한 cooler를 통해 식혀서 순환되는 폐쇄회로를 만들어 사용하는것이 특징이다.
Closed loop system의 특징
- 선박 내 Fresh water 를 wash water로 사용함
- Fresh water에 별도의 NaOH 주입이 필요함
- Open loop 대비 추가 장비 및 Sludge tank등이 필요하여 설치가 복잡하며, 설치비가 비쌈
- Wash water treatment 적용으로 배출수 관련 환경규제를 만족함
The closed loop is the most frequently used system. The seawater used in the process is continuously re-circulated. Detailed information can be found in our brochure.
How does it work?
- From the bottom of the scrubber exhaust gases are led through the scrubber to the top.
- The seawater is fed into the top of the scrubber through nozzles. This results in an equally divided spray.
- The outgoing exhaust gases are washed with seawater in the scrubber.
- The seawater (process water) is continuously re-circulated.
- The sulphur in the exhaust gases dissolves in the process water pumped from a circulation tank and binds with the caustic soda (NaOH) as a salt. Based on conductivity level a certain amount of process water is drained out of the system automatically.
- If needed clean seawater is then added to the process water tank and also NaOH, if needed.
- The process water is pumped through the separator.
- This separator will separate solids and oil from the process water.
- The remaining sludge is pumped to the sludge storage tank on the ship.
- The process water with high conductivity level will be discharged directly back to sea while complying fully to the IMO regulations.
- The pH, turbidity and concentration of PAH are constantly measured in accordance with MARPOL Annex VI resolution MEPC.184 (59).
- The clean exhaust gases exit the scrubber, removed from sulphur and particulates, through a demister.
HYBRID SCRUBBERS
Hybrid scrubber system은 Open loop system과 Closed loop system을 합성한 방식으로 선박 운항 시 유리한 운전모드로 변경이 가능하게 설계한 scrubber system이다. 예를 들어 대양에서 항해할 경우에는 open loop system으로 사용하다가 환경규제가 강화된 ECA 지역 또는 연안 항해나 세정수 배출물의 규제가 강화된 지역을 항해할 경우에는 closed loop system으로 전향하여 사용 가능한 장점이 있다.
Hybrid system의 특징
- 선박 운항 시 상황에 따라 운전 모드를 변경할 수 있어 operating cost가 적음
- Closed loop system 보다 복잡한구조를 갖고 있음
- 장비 가격이 고가인 단점이 있음
The hybrid scrubber system can run in both closed or open loop mode. Water is either re-circulated or discharged back to sea.
