Strive to Reduce Slurry Erosion and Cavitation in Pumps Through Flow Modifications, Design Optimization and Some Other Techniques: Long Term Impact on Process Industry.

Centrifugal pumps are being widely used in various industries for moving fluids that carry solids through pipelines where the need of head and flow rate is not high. Slurry erosion and cavitation are an extremely complex and not yet fully understood phenomenon that occur in centrifugal pumps; however, these undesirable phenomena can be reduced to a certain extent. Appropriate design and development of experiments is required to reasonably predict slurry erosion and cavitation. However, CFD methodology complements analytical solutions and experiments whenever testing of equipment has limitations. The current paper highlights the various slurry erosion and cavitation reduction techniques utilized by different researchers. Economic analysis conducted for a case study relevant to centrifugal pump (CP) usage in Pakistan shows that an 8% enhancement in pump efficiency can reduce the life cycle cost to about 17.6%, which could save up to USD 4281 for a single pump annually in Pakistan.

A new generation of zirconia supported metal oxide catalysts for converting low grade renewable feedstocks to biodiesel.

A new class of zirconia supported mixed metal oxides (ZnO-TiO(2)-Nd(2)O(3)/ZrO(2) and ZnO-SiO(2)-Yb(2)O(3)/ZrO(2)) has demonstrated the ability to convert low quality, high free fatty acid (FFA) bio-oils into biodiesel. Pelletized catalysts of ZrO(2) supported metal oxides were prepared via a sol-gel process and tested in continuous flow packed bed reactors for up to 6 months. In a single pass, while operating at mild to moderate reaction conditions, 195 °C and 300 psi, these catalysts can perform simultaneous esterification and transesterification reactions on feedstock of 33% FFA and 67% soybean oil to achieve FAME yields higher than 90%. Catalytic activity of the ZrO(2) supported metal oxide catalysts was highly dependent on the metal oxide composition. These heterogeneous catalysts will enable biodiesel manufacturers to avoid problems inherent in homogeneous processes, such as separation and washing, corrosive conditions, and excessive methanol usage.

Performance of heterogeneous ZrO2 supported metaloxide catalysts for brown grease esterification and sulfur removal.

In order to achieve a viable biodiesel industry, new catalyst technology is needed which can process a variety of less expensive waste oils, such as yellow grease and brown grease. However, for these catalysts to be effective for biodiesel production using these feedstocks, they must be able to tolerate higher concentrations of free fatty acids (FFA), water, and sulfur. We have developed a class of zirconia supported metaloxide catalysts that achieve high FAME yields through esterification of FFAs while simultaneously performing desulfurization and de-metallization functions. In fact, methanolysis, with the zirconia supported catalysts, was more effective for desulfurization than an acid washing process. In addition, using zirconia supported catalysts to convert waste grease, high in sulfur content, resulted in a FAME product that could meet the in-use ASTM diesel fuel sulfur specification (<500 ppm). Possible mechanisms of desulfurization and de-metallization by methanolysis were proposed to explain this activity.