There are three main types of desulfurization towers currently installed on ships: open desulfurization towers, closed desulfurization towers, and hybrid desulfurization towers.
Open desulfurization tower:
Open desulfurization towers use seawater to clean the flue gas. Seawater is generally weakly alkaline. In the desulfurization tower, the seawater is fully mixed with the flue gas by spraying, and the sulfur oxides are neutralized in the seawater, and the cleaned flue gas is discharged into the atmosphere. Open desulfurization tower generally includes: seawater supply system, desulfurization tower, control unit, washing water monitoring unit, flue gas monitoring device, etc.
Open desulfurization tower system composition control is very simple, the cost is relatively low, and it is easy to retrofit. However, the washing water needs to be directly discharged into the sea, which is not allowed in some countries and regions, and cannot be used in these regions, only low-sulfur oil or light diesel oil can be used.
Closed desulfurization tower:
The closed scrubber uses fresh water added with chemicals as washing water, generally using NaOH, Mg(OH)2, NaCO3, etc. Then, the washing water mixed with lye is used as the flue gas washing medium, and the washing water is recycled in the closed system and usually stored in the system cabinet. When the closed system starts, the circulating pump draws the washing water from the system cabinet, and after cooling by the heat exchanger, it is transported to the washing tower. During this process, seawater will be used as make-up water and cooling water. The water treatment system will continuously extract the washing water used for a long time from the system cabinet for treatment, so that the water quality can meet the standard. The lye will be used as the main reaction medium and will be continuously added to the washing water to participate in the desulfurization reaction.
The main components of the closed desulfurization tower system include: seawater supply system, fresh water cooling circulation system, desulfurization tower, control unit, waste water treatment device, washing water monitoring unit, dosing system, flue gas monitoring device, etc.
Closed desulfurization tower:
The closed scrubber uses fresh water added with chemicals as washing water, generally using NaOH, Mg(OH)2, NaCO3, etc. Then, the washing water mixed with lye is used as the flue gas washing medium, and the washing water is recycled in the closed system and usually stored in the system cabinet. When the closed system starts, the circulating pump draws the washing water from the system cabinet, and after cooling by the heat exchanger, it is transported to the washing tower. During this process, seawater will be used as make-up water and cooling water. The water treatment system will continuously extract the washing water used for a long time from the system cabinet for treatment, so that the water quality can meet the standard. The lye will be used as the main reaction medium and will be continuously added to the washing water to participate in the desulfurization reaction.
The main components of the closed desulfurization tower system include: seawater supply system, fresh water cooling circulation system, desulfurization tower, control unit, waste water treatment device, washing water monitoring unit, dosing system, flue gas monitoring device, etc.
The control of the closed desulfurization tower is relatively complicated, the cost is high, it is not economical in the open sea area, and the installation and transformation are relatively complicated. The washing water is not directly discharged to the sea, but is generally treated after arriving at the port, and there is no problem of polluting the seawater. Can be used in some controlled areas.
Hybrid desulfurization tower:
The open-type and closed-type desulfurization towers are mixed, which can be switched flexibly and inherit the advantages of open-type and closed-type desulfurization towers. But with the control, the composition is more complex and the cost is higher. Generally larger than the closed market and widely used.
