Page 287 - Managing Global Warming

Methane hydrate as a “new energy” 247

by calculating the amount of penetration of the piston in the cylinder from the pulse.
The pipe was made of stainless steel so that it could withstand high pressure. This was
the main feature of this testing apparatus used to measure the high pore pressure in the
depth of the seabed.
(h) Lower syringe pump
A mechanism similar to (g) was also installed.

(i) Gas mass flow meter
To calculate the MH saturation ratio, a mass flow meter for the gas was installed in the
pipe. The gas that passed through the device was measured as a mass flow (in units of g
1
min ) independent of temperature and pressure, and shown as flow volume (in units
1
of mL min ) standardized at 20°C and 1 atm. In addition, the amount of gas could be
1
calculated. The measurement range was 0–500 mL min , and when MH was disso-
ciated after the end of shearing, the amount of gas was measured while adjusting the
valve in the pipe equipped with the mass flow meter connected to the specimen.
(j) Device controlling the liquid temperature
This device was used to adjust the temperature from 35°C to +50°C within the tri-
axial cell by circulating the cell fluid in the triaxial testing device from an external
temperature controlled water tank. The temperature in the tank could be controlled
within a range of 0.1°C. To conduct tests at low temperatures, it was possible to
use a fluid with a freezing point below 40°C or to use aurorabrine, which has excel-
lent anticorrosion properties when in contact with various metals.

(k) Thermometer
A thermometer was installed near the side of the specimen in the triaxial room, so that
the temperature in the triaxial compartment could be measured. The temperature in the
cell was controlled based on the value indicated by the thermometer. When the tem-
perature was changed while performing the tests, adequate time was provided until the
temperature of the fluid and the specimen equalized.
(l) Methane gas cylinder
Methane for producing methane hydrate was stored in a gas cylinder which for safety
reasons was installed outdoors.
(m) Load cell
To eliminate the influence of piston friction, a cylindrical-shaped loading cell that
could not be affected by temperature and pressure was set up in the cell. The maximum
permissible load was 200 kN, and it was possible to measure with accuracy of up to
1/1000 of the full-scale load, as shown in Fig. 7.8F.
(n) Pipe
Methane gas flowed inside the pipe after the test, and to prevent the accumulation of
gas, the pipe was oriented vertically and as short a pipe as possible was used.