- August 14, 2014, Waste Management World

[The latest bad idea coming out of the polluting bioenergy industry.]


[[{"type":"media","view_mode":"media_large","fid":"301","attributes":{"alt":"","class":"media-image","height":"395","style":"width: 333px; height: 274px; margin: 3px 10px; float: left;","width":"480"}}]]A scientist at the University of Alberta, Canada is research to determine whether it’s effective to use pipelines to transport agricultural waste used in biofuels.

According to the university, Mahdi Vaezi, a PhD student in the Faculty of Engineering, is looking at agricultural wastes such as straw and corn stover which are used as feedstock for bio-based energy facilities.

Vaezi’s lab is claimed to be the only one in the world conducting this kind of research on biomass slurries.

The university explained that biomass material derived from food and non-food organisms has traditionally been transported by truck, at great expense. However, when done at a large scale, transporting biomass materials by slurry pipeline could help make the cost of biorefineries competitive.

The pipeline puzzle

When Vaezi began presenting his research papers in 2010, he had many skeptics. No one could be sure whether pipeline transport of agricultural waste biomass was even mechanically feasible, and there were questions about how much water would be required to create a slurry that would flow well, and how much energy the whole process would consume.

Vaezi, whose master’s degree focused on energy conversion, has answered most of the mechanical questions he set out to answer.

He knows how much water and energy are required and how agricultural waste biomass slurries behave. He has conducted studies on the viscosity of solid biomass-liquid mixtures, the pressure drop behaviour of the solid biomass-liquid mixture in the pipeline, and the performance of centrifugal slurry pumps handling biomass slurries.

He has also developed a numerical model to predict the loss of friction in the biomass slurry, which predicts how long it takes for a mixture to lose its pressure inside a pipeline. Variation in chemical specifications of biomass slurry through a pipeline is another area he has investigated in co-operation with the U of A’s Biorefining Conversions Network.

When he first arrived, his lab, the Large-Scale Fluids Lab in the Mechanical Engineering Building, needed considerable modification.

He needed a closed-loop pipe 25 metres long and two inches in diameter. He also needed to assemble much of the equipment and instruments used to measure flow specifications of the biomass slurry. It took months to determine what was needed, put in orders, await delivery, then install and calibrate the equipment.

On top of that, he has had countless disasters such as an overflow that had people in the offices below him a little distraught when water began to leak through the ceiling, as well as pump and pressure gauges that didn’t work and clogged pipes.  

Perseverance pays off

But perseverance paid off with a number of successes. Vaezi has had two papers published, and has three in review and another in progress. In November 2013, he received the prize for the best poster presentation at the Biorefining Conversions Network’s annual conference in Banff.

Vaezi is now analyzing the technical economics of moving agricultural waste biomass by pipeline. He is far enough along to know that transportation costs are considerably lower by pipeline than by truck.

“Transportation is a major component of the cost of both agriculture and forestry production, and therefore it merits looking at alternate transportation methods,” particularly at a time when so many people are questioning the use of pipelines,” commented Steve Price, executive director of Alberta Innovates – Bio Solutions.

The research is being led by Vaezi under the supervision of mechanical engineering professor Amit Kumar, the NSERC/Cenovus/Alberta Innovates Associate Industrial Research Chair in Energy and Environmental Systems Engineering. Vaezi’s research is funded by the Natural Sciences and Engineering Research Council of Canada, Alberta Innovates – Bio Solutions and the Biorefining Conversions Network.