Ocean Shipbuilding First Ballast Water Treatment System

On August 24th, Yangzhou Dayang Shipbuilding Co., Ltd., a subsidiary of Pacific Shipbuilding Group, successfully delivered the Crown DY5004, a crown ship built for German shipowners. Oceanic shipbuilding has overcome many difficulties. The ballast water treatment system was installed for the first time on the ship. The first ship used the principle of seawater inerting and deoxidation to treat ballast water.

Ship ballast water is used to adjust the balance and draft of the ship during navigation. However, when it is discharged from different places, the harmful aquatic organisms carried will destroy the ecological balance of the discharged waters and cause invasion of alien species. Therefore, the Global Environmental Protection Fund (GEF) lists the biological invasion caused by ship's ballast water as one of the four major hazards of the ocean. In order to effectively control and prevent the transport of harmful aquatic organisms and pathogens from ship ballast water, the International Maritime Organization (IMO) adopted the International Convention for the Control and Management of Ships' Ballast Water and Sediments in 2004, which established a clear implementation time. Table: From 2012 onwards, all new ships should be equipped with ballast water treatment systems, and all existing ships should be equipped with this technical device by the end of 2016.

Although the current ballast water management convention has not yet entered into force, the decision of the shipbuilding crown of the Ocean Shipbuilding Crown of 118,000 tons to install a ballast water treatment system on the ship is quite forward-looking. Because after the installation of the system, the ship meets the requirements of the new convention and maintains the technological leadership, this is a bright spot for the ship itself, which can lengthen the route and dock more ports of the country, thus improving the competitive advantage of the ship.

According to reports, Ocean Shipbuilding uses a ballast water treatment system produced by a US company on the bulk carrier, which has the characteristics of low price, low energy consumption and convenient use. Its working principle is to use the Venturi principle to treat the ballast water, that is, to use the venturi jet pump to speed up the ballast flow rate, thereby forming a vacuum zone on the back side of the venturi outlet and mixing the inert gas into the pressure. After being discharged with water, it will be discharged together, which will reduce the oxygen content in the discharged ballast water as much as possible, thereby effectively killing the microorganisms therein and achieving the purpose of not affecting the ecological balance of the discharged sea area.

The principle is simple, but the implementation is difficult. The use of this ballast water treatment system was designated by the shipowner. However, due to the immature technology of the system itself, there have been no cases of shipment. To this end, Ocean Shipbuilding has taken a number of measures and conducted several tests and commissioning. At the time of the initial test, Ocean Shipbuilding found that some of the cabin ballast water treatments did not meet the standard due to system design reasons. Later, they improved the pipeline configuration method and adopted different specifications of venturis in different compartments, thus solving this problem. . During the commissioning process, they also found that the combustion chamber could not automatically stop working when the pressure was too high. For this reason, the commissioning personnel and equipment service providers installed safety self-checking control devices on the system to improve the safety of the system.

In the installation process of this system, the ignition success rate has always been the focus of the debuggers. After the launch of the Crown's 118,000-ton bulk carrier “DY5004”, the commissioning personnel of the Ocean Shipbuilding Project Team began commissioning from the initial installation of the inert gas piping system, and ensured that there was no problem at every step. After the installation of the piping system was successful, a special person was arranged. The whole system was carefully debugged, and it took 42 days before and after, and finally the system was ready for trial before the trial. During the trial period, in order to solve the problem of low ignition success rate, they repeatedly adjusted the fuel-air mixture ratio and tested the running state and water treatment effect of the ballast water treatment system. After three days and three nights of hard work, the commissioning personnel finally completed the test of the ballast water treatment system before the end of the trial. The results show that the treated ballast water has an oxygen content of only 0.3-0.4 mg/L, which is less than half of the technical requirements and fully meets the standard requirements. At present, the German Lloyd's Register (GL) has officially recognized the system and issued a certificate, which is the first certificate issued by GL for ballast water treatment systems in China.