The flow of wheat straw suspensions in an open-impeller centrifugal pump

A laboratory-scale closed-circuit pipeline facility was modified to experimentally investigate the effects of pumping slurries of wheat straw and corn stover particles on the performance characteristics of a centrifugal slurry pumps. The effects of particle size and slurry solid mass content (concentration) on head, efficiency, and power consumption of a centrifugal slurry pumps were studied. In a clear contrast to the general performance of centrifugal slurry pumps in conventional solid-liquid systems, the total head height increased with an increase in slurry solid mass content due to several reasons including unique friction loss behavior (i.e., drag reducing feature) of fibrous particles slurries in pipelines. In addition, small size fibrous particles increased the pump efficiency more than the efficiency of the same pump handling pure water only. A correlation was finally proposed to predict the reduction in head while centrifugally pumping fibrous agricultural residue biomass (wheat straw, corn stover) slurries, compared to the head produced while handling pure water only. The results could be used in the design and operation of centrifugal slurry pumps to transport fibrous agricultural residue biomass materials. However, the effects of other parameters like air in the system and anaerobic problems should be taken into account too.