Optimization and cost analysis of lignocellulosic biomass feedstocks supply chains for biorefineries

This study estimated the biomass harvest and transport cost considering single pass biomass harvest with bulk and bale collections of biomass. Lignocellulosic biomass feedstocks costs were estimated using both corn stover and switchgrass as part of the feedstock supply chain. Harvest and transport cost for multi-pass biomass harvest operations using multiple feedstocks were analyzed and the optimal number of Machines for all unit operations were estimated for each supply chain. This dissertation calculated and compared the biomass harvest and transport cost for single pass biomass harvest with bulk and bale collections of biomass. The objective of the research was to find the optimal number of Machines, and least cost biomass harvest and transportation costs based on the harvest Window, Machine capacity, farm sizes and yield of the biomass. The least cost model was developed using the mixed integer non-linear programming model developed in General Algebraic Modeling System. The cost of harvest and transport using the bulk stover collection method was estimated about $25 Mg -1 ($23 ton -1 ) considering a transport distance of 3.2 km (2 miles) for primary storage from the field with the harvestable stover yield of 4.4 Mg ha -1 (2 ton ac -1 ) for the farm size of 2,000 ha. (5,000 ac.) Biomass feedstocks cost at the gate of biorefinery was estimated for multi-pass harvest systems with multi-feedstocks. Corn stover was considered a by-product of grain production and switchgrass as a single product. Planting and establishment cost was also considered along with harvest and transport cost for switchgrass. The cost of switchgrass varied from $75 Mg -1 to $97 Mg -1 ($68 ton -1 to $88 ton -1 ) and cost of corn stover varied from $75 Mg -1 to $97 Mg -1 ($20 ton -1 to $25 ton -1 ) respectively with the farm sizes variation from 400 ha to 2,000 ha (1,000 ac to 5,000 ac).