Prepared by Laura Suleimenova
Emergency emission of fuel gas at Kashagan. Illustrative photo from "Ak Zhaik" archive.In Beryozovka village in West Kazakhstan Oblast 25 children and 4 adults were hospitalized as the result of poisoning with unknown substance. Local people believe that the cause of poisoning is the production of oil and gas at Karachaganak field located within several kilometers from the above village. Meanwhile, the Atyraulians also have reasons for concern: we have major Bolashak oil and gas processing plant near the city.
AkZhaik newspaper got hold of the report of the Republican Research Center for Protection of Atmospheric Air containing the research results of the impact of Bolashak plant on the air basin of Atyrau. The research was carried out with the use of mathematical modeling methods of dispersion of polluting substances (PS) in the atmosphere under various operating conditions of the plant: a regular operating mode in winter and summer time; burst releases during fuel gas flaring at high and low pressures; possible emergency situations caused by fire at the plant.
From the report it follows that when the plant operates in normal mode, including situations of fuel gas flaring during burst releases, “limit-exceeding concentrations of any of the substances contained the emissions are not expected in the residential zone (Atyrau). Experts revealed possible excess of norm only on the border of a sanitary protection zone of the plant on three polluting substances out of 39 - etilmerkaptan (196.55 maximum concentration level-mcl), methane (1.6170 mcl) and metilmerkaptan (11.858 mcl). Also the main source of this hazard has been identified – “a gas bleeder on block valves of fuel gas pipeline at Unit 420”. In this regard the authors of the report recommended to reconsider the earlier approved dimension of the sanitary protection zone and increase it.
Further the report reads that the most negative impact on atmosphere will be in case of possible fire at Unit 220 designed for transportation and storage of crude oil. In such scenario the maximum concentration limit at the border of sanitary protection zone may exceed tens and hundreds of times. “The highest possible level of pollution is recorded for hydrogen sulfide (258.68 mcl at the sanitary protection zone border and 19.423 mcl in the residential zone)”.
Altogether in case of fire an unscheduled emission into the atmosphere is possible that would contain at least 8 polluting substances. With that, “the area of excess pollution of the atmosphere with some substances contained in the Bolashak plant emissions can have an extremely wide spread occurence, not only outside the sanitary protection zone of the plant, but also covering the most part of the Atyrau Oblast territory, as well as the part of the neigbouring Aktobe Oblast”.
Thus, the emergency situation at the plant with possible large-scale fire can lead to local and even republican scale environmental disaster, -concludes the researchers’ report.