THE FURUKAWA ELECTRIC CO., LTD.

We started to study how to transport and store liquid carbon dioxide at the bottom of a deep sea by medium pressure flexible pipe from 1997.

The summary of the study in 1998 is described as follows.

For the prototype of the pipe to transport a large amount of liquid carbon dioxide at the bottom of a deep sea, two types of the pipes with the differ kinds of the light armor wires were designed and trialy manufactured by our facilities.

One of the light armor wire is a composed wire constructed with a conventional steel wire of thin lod covered with a thick polyethylene jacket which enable the weight of the armor wire lighter. Another light armor wire is a newly developed full plastic wire with the higher tensile strength and the good elasticity.

As for the pipe with composed light armor wires, the measurement of the basic mechanical properties like the axial stiffness,the bending stiffness and the torsional stiffness were carried out. Further, the mechanical strength of the pipe with composed light armor wires, such tensile strength, torsional strength, bending strength, collapse strength and combined strength of the bending and the tensile force were examined. To carry out each mechanical strength tests, specially designed end-fittings of the pipes and the arrangements for the tests were prepared. The results of the mechanical strength tests were approximately agreed with the estimated values.

Also, from the results of the machanical strength tests, some problems for the actual use of the pipes were clarified. The stress analysis of the each crosssectional area of the pipe by finite element method was carried out to evaluate the collapse strength of the pipe.

Numerical analysis and evaluatuions for the tensile and the torsional behavior of the pipe were derived from the armor wired model.

Before trial manufacturing of the pipe with newly developed full plastic armor wires, the armor wire was carefully inquired whether it was adequate for the rein forcing material from the points of view of the strength, specific gravity, cost and some other physical properties and finally approved.

In 1999, the examinations of the baisic properties for the pipe with full plastic armor wires and the evaluation tests of the endurability for both types of the pipe are scheduled. Further, the studies of the method how to install the pipes from the surface to deep sea and the computer aided designing of the optimum installing systems are planned.