Victor Zavala Tejeda
Baldovin-DaPra Associate Professor, Department of Chemical and Biological Engineering, University of Wisconsin-Madison
Coordinated management of agricultural waste and high-tech value bioproducts
The concept of Biorefinery originated in the 1990’s as a result of fossil fuel shortages and increasing trends in the use of biomass as a renewable raw material for the production of non-food products. The mismanagement and disposal of agricultural waste represents not only a danger to the environment, but also a lost economic opportunity. Specifically, there are various biomass processing technologies to generate value-added products from organic waste such as building block chemicals, fuels, and electricity. Unfortunately, the economic viability of waste processing routes depends to a large extent on the scale, transport costs and composition of agricultural waste (which vary depending on waste). Moreover, decision-makers are often unaware of the potential uses of waste streams and, therefore, of their inherent value. Another obstacle associated with waste management is the lack of cost-effective alternatives to collect and transport large quantities over long distances. In Mexico, government regulations and incentives for the use of biomass are currently in place, however, incentives have not been able to exceed production and logistics costs. Therefore, there is no waste management network that guarantees a strong market, sustained growth for the urban and agricultural sectors.
This work proposes a coordinated framework for the management of lignocellulosic biomass from agricultural waste (corn stover, wheat straw and sorghum stover) in a scalable way by organizing the exchange, distribution, transport and transformation of biomass into value-added bioproducts, specifically: Levulinic acid and Furfural. These high value-added products were selected because they are precursors of methyltetrahydrofuran, which is an additive that can be mixed with gasoline and has a demand of more than 20,000 kilo tons. The state of Guanajuato was taken as a case study, which is the second state in Mexico with the highest generation of agricultural waste that contribute 10.2% of the national generation. This type of framework is inspired by the coordinated systems with which power grids currently operate in the world. Within the proposed framework, biomass suppliers, technologies involved in processing and transport suppliers participate in a coordinated system that is operated by an independent system. The operator solves a dispatch problem that maximizes social welfare and balances supply and demand in a specific geographical area, for this, the operator obtains all the locations, the prices of different biomass and derived products. Coordination allows the management of complex constraints and interdependencies arising from the transport and physicochemical transformations of biomass into value-added bioproducts. The market includes all suppliers and demands, regardless of capacity or geographic location. As a result, the coordinated system delivers prices and product allocations that meet the economic and efficiency properties of a competitive market. Through the coordinated framework, cleared transportation flows, locations and technologies involved are obtained to meet demand. The production of levulinic acid was 434 Kt / year and that of Furfural 487 Kt / year. Which represent 3.8% of global demand of raw materials for methyltetrahydrofuran. On the other hand, the benefit generated to biomass suppliers exceeds $30 million, which would represent an increase in social welfare in the area, specifically to farmers. The framework allows to identify guidelines of the market behavior taking into account all market players, with these guidelines is possible propose actions to be able to project a more competitive market for all products and that favors all market players. In addition, the framework can facilitate the coordinated distribution of food, transport, or some other product.
Victor M. Zavala is the Baldovin-DaPra Associate Professor in the Department of Chemical and Biological Engineering at the University of Wisconsin-Madison and a computational mathematician in the Mathematics and Computer Science Division at Argonne National Laboratory. His research interests are in the areas of mathematical modeling of energy, chemical, and agricultural systems, high-performance computing, and computational optimization. He is co-director of the Texas-Wisconsin-California Control consortium, under which he works with industrial partners such as ExxonMobil, Johnson Controls, and Genentech. His awards include the Presidential Early Career Award for Scientists and Engineers, the NSF CAREER Award, the DOE Early Career Award, and the Young Investigator Award from the CAST Division of AIChE.