2B.Research on Oil Spill and Rafts Response

Background and Objectives

  • Large-scale oil spill incidents still occur worldwide despite every effort to prevent them. Such incidents cause tremendous environmental damage and economic losses. In the home waters of Japan, the damage caused by the disastrous 1997 Nakhodka tanker accident is still remembered today, and the accident near Taean (South Korea) in 2007 has created a similar tragic legacy.
  • The oil spill from a subsea oil field in the Gulf of Mexico in 2010 caused damage estimated at 2 trillion yen. Another serious oil-spill incident occurred at the Bohai oilfield (China) in 2011. Yet the risk of oil spills is expected to continue as the Sakhalin Project in the Sea of Okhotsk and the development of oilfields in the East China Sea progress. In another incident, oil spilled from a ship off Busan, South Korea reached the coast of Shimane Prefecture taking
    more than a week in January 2013.
  • Additionally, the disposal of garbage and oil products at sea occurs on a daily basis. This obstructs ship traffic and has adverse effects on the environment.
  • The government has deployed 5,000-ton class dredging and oil recovery vessels to respond to large-scale oil spills, along with 200-ton class environmental improvement vessels for collecting floating garbage and oil in inner bays.
  • This research is providing technical support for garbage and oil collection by state-owned vessels, by upgrading functionality and improving efficiency while aiming to create damage-mitigation methods based on technological development. Since the Great East Japan Earthquake, we also take into account oil spills caused by earthquakes and tsunamis.

Research topics

  • In order to reduce pollution caused by oil spills, it is important to have technologies that can more efficiently recover spilled oil as well as for assessing the preliminary risk. We have already developed a variety of oil skimmers and other devices, and we continue to upgrade existing technologies while addressing new issues. In regard to preliminary risk assessment and other support technologies for responding to oil pollution, we are developing tools for oil spill detection, capture, and drift prediction.
  • Sunken timber and other debris, in addition to floating garbage, cause problems such as entanglement with the trawl nets of fishing boats as well as adverse effects on the environment. Thus, we are developing equipment for state-owned environmental improvement vessels in order to facilitate the quick collection of sunken timber and other debris.

Activities in FY 2014

  • For the efficient maintenance and management of oil recovery vessels and oil skimming equipment as well as cost reduction, we examined how to remove oil from the vessels and equipment. Also, in order to improve the performance of oil skimming equipment, we studied the characteristics of high-viscosity oil passing through mechanical elements such as gratings and the flow promotion technology in order to develop oil skimming equipment that can handle high-viscosity oil.

Photograph 1.1.1.3 Oil removal experiment by shot blasting

  • We technically examined the methods for protecting important port facilities for which quick clearing is required in case of an earthquake/tsunami disaster that causes oil spill damage. We carried out experiments using a bubble curtain and analyzed the oil removal effect of bubbles.

Photograph 1.1.1.4 Study on methods of improving the grating passing characteristics of high-viscosity oil

  • We studied the development of a new model for calculating the range of oil drift due to tsunamis by combining STOC, a numerical simulation model that can precisely reproduce tsunamis, with OIL-PARI, a numerical simulation model that can reproduce the advection and diffusion of oil spilled on the sea.
  • We also modified the drift oil capture system (developed version) for predicting the advection and diffusion of spilled oil and helping the recovery of oil using recovery vessels, which had previously been developed, to enable predictions up to approximately 10 days ahead and improve the operability.

Figure 1.1.1.9 Calculation of the drift range of oil after a tsunami (Blue dots indicate the
positions of oil.) Steering system display

Figure 1.1.1.10 Example of calculation using the modified drift oil capture system (developed version) (Blue dots indicate the positions of oil.)

 

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