The challenge in understanding the corrosion mechanisms under oxyfuel combustion conditions

Basic research on the corrosive effect of flue gases has been performed at the BAM Federal Institute for Materials Research and Testing (Germany). Conditions at both high and low temperatures were simulated in specially designed experiments. Carburization occured in flue gases with high CO₂ content and temperatures higher than 500 °C. In SO₂ containing flue gases sulphur was detected in the oxide scale. At lower temperatures no corrosion was observed when gases with low humidity were investigated. Humidity higher than 1500 ppm was corrosive and all steels with Cr contents lower than 12% revealed corroded surfaces. At low temperatures below 10 °C a mixture of sulphuric and nitric acid condensed on metal surfaces. Acid condensation caused severe corrosion. Humidity, CO₂, O₂, and SO₂ contents are the important factors determining corrosion. Below 300 °C acid condensation is the primary reason for corrosion. Low humidity and low temperatures are conditions which can be expected in the CO₂ separation and treatment process. This work includes major conditions of the flue gas and CO₂ stream in CCS plants and CCS technology.     

On the cytotoxicity of some microbial volatile organic compounds as studied in the human lung cell line A549

The cytotoxicity of 13 microbial volatile organic compounds (MVOC) was studied using a human lung carcinoma epithelial cell line A549 in a colony formation assay and two colorimetric assays: the microculture tetrazolium assay (MTT assay) and the cellular protein assay (methylene blue-MB assay). For comparison, two known cytotoxic substances: the non-volatile mycotoxin gliotoxin and the mono-functional alkylating agent methyl methanesulfonate (MMS) were studied. Concentration-response curves for each agent were established and the IC50 value (concentration resulting in 50% inhibition of colony growth or absorbance) was estimated. There are differences in toxicity levels between the MVOC tested and gliotoxin and MMS. The most toxic MVOC was 1-decanol which was as effective as MMS in all test systems. 1-decanol was about 10-fold more toxic than the other MVOC. All MVOC tested were more than 1000-fold less toxic than gliotoxin.     

Risk management in the Federal Republic of Germany

Spectacular industrial accidents, such as the ones in Bhopal, Mexico City, and Basle, have in recent times made the risks associated with the modern chemicals industry unmistakably evident. It has been seen that effective emergency plans for the people living in the vicinity of a hazardous installation become particularly important. The situation of hazardous installations in the Federal Republic of Germany is reviewed and the three-stage safety system, which is established within the German Regulation on Major Industrial Accidents (Störfallverordnung), is described. The evaluation of the current practice shows a couple of problems, especially connected with off-site safety precautions. The disaster control teams are often ill-equipped and inadequately trained. There is a need for further establishment of detailed and specific emergency plans, especially in rural areas. It is expected that the updating of the Regulation on Major Industrial Accidents, which is at present being undertaken in the Federal Republic of Germany and the compilation of instructions for the competent authorities will contribute to better emergency plans for the protection of areas in the vicinity of hazardous industrial installations.     

Butyltins in shellfish, finfish, water and sediment from the Coos Bay estuary (Oregon, USA)

Butyltin was measured in tissue, water and sediment samples collected throughout Coos Bay estuary between 1986 and 1997. Butyltin-induced shell deformation in commercial oysters prompted this assessment. Butyltins are released from tributyltin oxide (TBTO)-containing boat paint. Clams from three sites contained tributyltin (TBT) levels ranging from 168 to 457 microg/kg in 1992-1994. Consequently, Oregon Health Division (OHD) issued a shellfish consumption advisory in 1995; it was rescinded in 1997 after US Environmental Protection Agency (EPA) revised the TBTO oral reference dose (RfD). The revised RfD changed the tissue screening level from 112 to 1120 microg TBT/kg. Fifty percent of sediment samples collected during 1991-1997 and analyzed for total butyltins (TotBT) exceeded the Puget Sound Dredge Disposal Analysis Screening Level (PSDDA SL) of 73 microg TBT/kg dw. TotBT at three shipyards selected for site assessment by EPA ranged from 24 to 68,613 microg/kg dw. Sediment and tissue butyltins have been decreasing in all but one area of the estuary.