| Popis: |
Underground storage of petroleum products has been practiced for nearly 70 years but only recently have large volumes been storage for longer periods. Spaces in sedimentary rock or artificially created cavities in salt formations or in rocks are used. Microbial problems are presented associated with over 40 years of storage of hydrocarbons in unlined rock caverns in Scandinavia. This system has been successfully operated in Sweden until recently, when it was observed that in a few cases, jet fuel became corrosive due to H2S production and that dangerous levels of methane gas were found in caverns with heavy fuel oil. Problems with sludge formation, corrosion and formation of emulsions have also been noted. The rate of biodeterioration in caverns is affected by the amount of oxygen and nutrients supplied to the system. Other factors of importance are pH, temperature, composition of the stored product and the rate of accumulation of water. A close interaction between aerobic and anaerobic processes has been observed. Alternative methods to inhibit the microbial activity have been evaluated as well as suggestions for structural modifications of the caverns. |
