Experts try to cool temp of styrene storage tank
Aim is to pump water directly to the shell to bring the heat down
A team of experts managed to bring down the temperature of the styrene liquid in its storage tank to 97.9º Celsius with almost no release of toxic fumes by Saturday evening, giving the much relief to people living in the vicinity of the LG Polymers plant near Visakhapatnam and also to the state government.
The tank is 12 metres tall and 18 metres in diameter. It has a two-inch external tin sheet layer and 12-inch mild steel insulation cover to secure 1,800 metric tonnes of liquid styrene, the structure being similar to the thermos flasks used at home.
Authorities are removing the external tin cover from the bottom of the tank wherever possible to expose the inner insulated shell. This process has to be done carefully to ensure there is no damage to the insulated shell.
They will use the space to pump water directly on the inner shell to cool the liquid styrene to its normal temperature of 32º C.
The authorities who are supervising the salvage operation said that the refrigeration unit at the bottom of the storage tank which maintains the temperature below 25ºC was shut, and use of the polymerisation inhibitor paratertiary butyl catechol (PTBC) was discontinued as no polymerisation was taking place in the tank.
By doing so, the authorities are expecting to make space to spray water on the inner insulated shell which will help in cooling the styrene enough to solidify in the rest of the tank. The upper portion of the liquid styrene has already solidified.
A senior official from department of factories said, “Removal of the external tin sheet has to be done carefully to ensure there are no sparks.”
AP Pollution Control Board authorities found that there was no presence of volatile organic compounds mixed in the atmosphere after Thursday’s leak of styrene. At some places, however, it was recorded as 2.3 parts per million (ppm) and 0.6 ppm in others.
As a precautionary measure, the people evacuated from nearby villages may not allowed to go back to their homes immediately and will be accommodated at the rehabilitation centres for some more time, a PCB official said.