Publications

A technoeconomic analysis of the potential for portable pyrolysis in Northern New Mexico forests

Brown, Alexander L.; Brady, Patrick D.

Biomass pyrolysis systems can be designed to yield significant quantities of liquid. The liquids have approximately half the heating value of transportation fuels, depending strongly on the water content in the liquids. They are acidic, and tend to change with time, becoming more viscous and higher in molecular weight. However the process required to generate them is simple, and they hold promise to be a renewable source of liquid fuel if they can be produced in a way that is cost-effective. Northern New Mexico forests are mostly characterized by small diameter (less than or equal to 10 cm) conifer trees. For mitigation of fire risk, land owners are required to periodically thin their lands. This generates significant waste product with little or no commercial value. The most widely used current practice is to accumulate and burn the cut wood, or to leave it to rot. Seeking a more effective and ecologically friendly use of the waste, a scaled experimental pyrolysis system was developed using design principles focused on the portable model. The data from this test unit and historical data are used to evaluate the break-even costs of performing pyrolysis. The char co-product is found to have a slight beneficial effect on the economics of the analysis. Labor is a significant fraction of the cost. Economies of scale are important, so the largest system that can be transported will make the most economic sense. On a price per unit energy, this model may be competitive with liquid transportation fuels and fuel oil. However pyrolysis oils will have difficulty competing with natural gas at current regional prices. Other regions may show a more positive comparison, especially in parts of the world where labor is much less expensive. Copyright © 2012 by ASME.