Bridge towards Low Carbon Society
~CCS System Project with CO2 Shipping~
Greenhouse gas emissions including CO2 are discussed globally. However, economic society is supported by the usage of coal, oil and natural gas which associate with CO2 emissions, and it takes time in order to switch to low carbon energy system. Carbon Capture and Storage (CCS) is an idea of separating CO2 from the atmosphere by injecting CO2 produced from energy system into underground or the deep ocean. With expectations arise towards a technical policy planning on immediate energy and environmental harmonization led by Europe and America, the phase is entering another step for large-scale demonstration experiment. However, it is the present condition that it is still difficult for CCS to be deployed along the shore of our country.
Therefore, our laboratory suggested on CO2 shipping, and injection of CO2 into the offshore well at deep ocean region, instead of transporting CO2 through offshore pipelines, with research and development carried out on the study of technical and economic feasibility of this system. The advantages of CO2 shipping CCS system are, ①There is no need for specific matching between location of CO2 capturing factories and the storage well, ②Offshore pipelines is unnecessary, ③If the number of storage site is small, centralized control on geological survey, environmental assessment and monitoring is proved to be effective, ④Suitable for addition or changing of plan, ⑤Various business entities are able to participate regardless of their quantity of CO2 emissions.
Preliminary Study on Thermal Power Plant Cooling Water System without Water
~Intake and Discharge Using Deep Sea Water~
Most steam power stations in Japan are located on the shore and use surface layer sea water for cooling of the turbine steam. Since the sea water temperature rises (+7ºC) and being drained back to the sea, the influence of warm waste water diffusion and coast ecosystem becomes an important issue. In addition, a change of the seawater temperature with the season becomes the big factor of inefficiency of the electricity generation.
Therefore, Ozaki Research Laboratory proposed on a new cooling water system to improve power generation efficiency and avoids thermal discharge problem. In other words, the system circulates cooling medium in closed looped pipeline between condenser of power station and cold region of the deep sea: the system use the low temperature feature of deep sea water for cooling of the turbine steam without warm-water discharge.
Towards Economic Exploration of Deep Sea Gas Field
~Utilization System of Deep Sea Water for Gas Cooling of Floating LNG (FLNG)~
For the reason of diversification and decentralization of energy resources, Liquefied Natural Gas (LNG) business by shipping has been growing globally. While the energy demand keeps expanding, the exploration of deep sea gas field has become target of interest, and therefore the development of a practical technology for production, liquefaction and storage FLNG plant moored on the ocean, with LNG shuttle transportation system is necessary.
Our laboratory develops a new utilization system of deep sea water for gas cooling of FLNG, and involves in research to
Drilling through Ocean Crust for Scientific Mantle Research
~Challenging the Ultra-deep Ocean Drilling~
The latest advanced technology is required to drill through the deep oceanic crust in order to obtain high quality core sample for scientific research purposes. Rotating the bit smoothly at the end of the drill string which is hanging all the way down from the drill ship by a long drill pipe, with constant force acting on the cutting tooth of the bit are few of our main objectives. In our laboratory, research is carried out on the behavior estimation method taking consideration of interference and elasticity between the ultra-deep sea drill pipe and fluids inside borehole. Furthermore, research and development on coring system to be installed at the front end of the drill string is also our main target. These researches are important for drilling and exploration of ocean resources, including future ultra-deep ocean drilling to reach the upper mantle.
Ocean Space Utilization
~Vertically Movable Tension Leg Mooring System~
A concept of "vertically movable tension leg mooring system" is proposed for the purpose that an offshore floating body subject to comparatively large static horizontal loads for its scale, which is represented by floating wind power generator, ocean current power generator, etc., is moored so that the occupied plane area of the mooring system may become as small as possible. In the system, a gravity type template is hung from the floating body with vertical lines and the template is moored with relatively short catenary chains to seabed anchors. The advantages of the proposed system are discussed comparing mainly with the tension leg mooring, and the fundamental mooring characteristics are shown with model calculations.