Weir Minerals has announced an upgrade to its polymer-ceramic composite for the Flue Gas Desulphurisation (FGD) market, where mined limestone is ground and used used to remove sulphur dioxide from exhaust flue gases in coal fired power plants. Specially engineered for use in FGD applications, the new and improved Cerasmooth™ compound is designed to provide ultimate wear and corrosion resistance.“We are focused on the continuous improvement of our materials, which is why we have enhanced our existing formulation to improve component wear life and meet the ever more demanding market’s needs,” states Patrick Moyer, Executive Vice President of Engineering for Weir Minerals.Cerasmooth™ material was developed for the Warman® GSL pump series but can also be used for any acidic, light slurry application. The FGD application is very unique. It can experience wide variations in pH during operation and also contains erosive components in the slurry. This makes it difficult to select an optimum metal solution to cover the range of possible conditions. Materials used in this application need to be capable of handling these demanding and varying operating conditions.“At Weir Minerals, we provide value by delivering materials and solutions aligned to the industry’s needs, which is why we developed Cerasmooth material. The polymer matrix of Cerasmooth is almost impervious to the extremely acidic environments that can occur in FGD duties, and the ceramic filler provides outstanding wear resistance to the typical erosive particles in the slurry,” says Edward Humphries, Director of Research & Development for Weir Minerals.Cerasmooth™ compound has an equal combination of erosion and corrosion resistance, which work together to deliver optimum life in an FGD circuit, offering customers longer wear life than ever before. “Significant in-house wear testing has shown that up to 60% improvement over the previous polymer ceramic material offering can be obtained. This has been achieved by successfully improving the bond that holds the wear resistant silicon carbide grains in place during the wear process,” states Humphries.In addition, the uniquely formulated composite material boasts increased mechanical strength and improved strain characteristics. “Achieving flexible strength as high as double that seen in first generation materials,” says Humphries. By utilising Cerasmooth™ material, operators can significantly improve the service life of their pump compared to metal and rubber liners. Compared to a rubber lined pump, Cerasmooth™ compound has an increased ability to withstand the cutting damage that can be caused by pipe scale coming loose from the FGD circuit and passing through the pump.Cerasmooth™ material was developed through a rigorous process of testing various polymer binders and ceramic fillers to find the optimum combination to deliver the performance required.“Weir Minerals recognises the importance of material development for its customers and continuously produce state-of-the-art materials to improve component wear life.”
An intercomparison of zenith-sky UV-visible spectrometers was held at Camborne, UK, for 2 weeks in September 1994. Eleven instruments participated, from nine different European institutes which were involved with the Second European Stratospheric Arctic and Mid-latitude Experiment (SESAME) campaign. Four instruments were of the Systeme d’Analyse d’Observations Zénithales (SAOZ) type, while the rest were particular to the institutes involved. The results showed that the SAOZ instruments were consistent to within 3% (10 DU) for ozone and 5% for NO2. For ozone the results from these instruments agreed well with total ozone measurements by Dobson and Brewer spectrophotometers and integrated ozonesondes when the air mass factors for the SAOZ were calculated using the ozonesonde profiles. Differences of up to 10% in ozone and 30% in NO2 were found between different instruments. In some cases these differences are attributable to the different absorption cross sections used in the analysis of the spectra, but other discrepancies remain to be investigated. A prominent source of error identified in the campaign was uncertainty in the derivation of the amount of absorber in the reference spectrum, which can contribute an error of up to 3% (10 DU) in ozone and 1.5×1014 molecules cm−2 in NO2.