Petronet-LNG begins 'hydro testing' first LNG tank

Vol 7, PW 5 (21 May 03) Midstream & Downstream

FOR PETRONET-LNG, 8th May was a special day.

That evening it began pumping water into the first LNG storage tank, a process called 'hydro testing'. With a capacity of 168,000 cubic metres, it will stay filled with water for a month to check for leaks and to see how much its 578 piles settle into the soil.

At the end of the test, the water will be pumped out and into the second LNG for the same test. Inside the cavernous second tank, scores of workers are at work.

Some are fabricating the casings for the level transmitter and the pumps, others are welding the inner metal shell to the floor rim while several workers are perched high above giving finishing touches before closing the tank for the hydro test. The two LNG tanks are key milestones for the Dahej terminal.

After testing, insulating foam will be injected into the space between the outer and inner walls of each tank, which will then be sealed tight, never to be opened again. The tanks close to completion, PLNG is shifting focus to the regassification facility of seven shell and tube vaporisers containing 112 air heaters, two stand-by submerged combustion vaporisers, one 18-MW captive power plant and two boil-off gas recovery units.

"The regassification facility is 70% complete," says engineer Rajinder Singh. "We are on schedule." A short distance from the LNG tanks, a gentle slope leads to the 2.4-km long approach road perpendicular to the coastline, over a stretch of the Arabian Sea to the LNG jetty.

Completed on 12th January, the road carries two 30-inch pipes to transport LNG from the ship to shore, one 10-inch vapour balancing pipeline from the onshore LNG tanks to the ship, one 20-inch pipeline for fire fighting water and several electrical cables. At intervals along the road, workers are insulating the LNG pipes, welding sections together.

"All that remains now is to connect the LNG pipelines to the loading platform on the jetty," says engineer Narender Asija. "Work at the approach trestle and the jetty is 70% over."