Sudipto Mondal

Staff allege that overloading caused the system to collapse

Power supply to the main control room was cut off

Emergency support system for back-up power also failed

MANGALORE: Barring one crude-oil refining unit, work at nine other units of Mangalore Refinery and Petrochemicals Ltd. has come to a standstill following an electrical short-circuit on Monday evening.

The short-circuit, which occurred in substation 4 of the oil movement and storage (OMS) area, was kept secret until some employees of the refinery brought it to the notice of The Hindu. The MRPL management has acknowledged the accident and consequent closure of many units.

Presently, the crude distillation unit (CDU) number 1 is the only one that is working. Work at the second CDU, two hydrocracker units, two visbreaker units, two sulphur recovery units as well as two continuous catalytic reformer units have come to a halt. The plant is working at about 30 per cent of its capacity.

Sources in MRPL said that the short circuit in the OMS resulted in a “multiple reverse ripple effect”, resulting in the shutting down of all previous electrical circuits leading to substation 4.

This backward tripping ended at the main control room. The control room, which MRPL technicians described as the “brain” of the plant, was rendered useless for nearly an hour.

“The men in the control room did not know what was happening outside because all their monitoring systems crashed,” said a source. The emergency support system, which provides back-up power supply at such times, also failed. Soon there was a complete blackout in the plant.

The blackout set off a series of events. All hydrocarbons in the refinery are maintained at a temperature between 200 and 400 degrees Celsius. With the sudden power outage, these temperatures also began to plummet.

The cooling down of the plant caused the sudden contraction of equipment. These contractions, also known as “terminal shocks”, led to the collapse of a brick wall in the crude distillation unit, which is the “mother plant” of the refinery. Several tubes in the CDU unit and the oil pipe of steam turbine number 5 cracked. The oil began to drip onto the hot steam turbine and caught fire.

Sources in the employees union allege that this accident was caused because the plant was working at over 120 per cent of capacity.

Confirming the above version of events given by sources as “accurate”, Deputy General Manager (Corporate Communications) of MRPL Lekshmi Kumaran said that the accident was caused by a rat that snipped the power cables. She confirmed that an inquiry team had been constituted under Group General Manager (Materials) K.S. Koppalkar.