Intense flaring was recorded at Lukoil Neftochim Burgas after a sharp drop in the power supply voltage to virtually zero. As a result, nearly 80% of the process installations were shut down as a precaution, while black smoke and intense flames rose from a flare stack.
The refinery explained in a written statement to BNT that the cause was external to the facility and related to the Kameno substation, which operates at 110/20 kilovolts. Scheduled maintenance work was being carried out there at the same time.
A three-phase short circuit occurred at the substation, causing three consecutive voltage disturbances. They lasted 400 milliseconds, one second and another 400 milliseconds, respectively. The Electricity System Security Operator is expected to determine whether this was due to human error or a technical fault.
Flare stacks are part of the safety system
Lukoil Neftochim Burgas said that no external electrical disturbance of such depth and scale had been recorded at the refinery in the past 25 years.
The refinery has four hydrocarbon flare stacks and one hydrogen sulfide flare stack. Under normal operating conditions, they are constantly on standby, with only the pilot burners operating. When equipment and process installations are started up or shut down, the flare systems receive the released gases and burn them in a controlled manner to prevent them from accumulating and being discharged directly into the atmosphere.
The flare heads use steam for smokeless combustion. When hydrocarbon gases enter suddenly and in large quantities, time is needed to regulate the steam supply. It is during this transition period that black smoke may appear, caused mainly by fine soot particles resulting from incomplete combustion.
No exceedances of monitored indicators recorded
According to operational information provided by the refinery, monitoring stations in Burgas, Kameno and Dolno Ezerovo did not record any exceedances of the controlled pollution indicators as a result of the flaring. The facility’s independent monitoring systems also recorded no exceedances.
The refinery said that it had received no complaints from citizens related to air pollution. “At present, there are no grounds for concern among the population,” the statement said.
Sources: bntnews.bg