John S. Cundiff

Department of Biological Systems Engineering, Virginia Tech, U. S.A.

12.3 Introduction

Society collects raw materials using the following extraction activities: mining (which includes drilling for oil and natural gas), logging, farming, fishing, and hunting. Mining is a “point source” extraction of raw materials. Some geological event has deposited a high concentration of the desired raw material at a given location, and a mine is established at this location. Typically, a rail line, pipe line, or marine port is built to cost-effectively transport the raw material to distant utilization points.

Biomass is unique among the raw materials used by society in that it is a distributed resource. It must be collected from production fields/forests and accumulated for processing at a central location. This chapter primarily covers farming with some minor reference to logging. Fishing and hunting (relatively small in developed countries) are not covered.

This chapter is written to guide the reader through the thought process they will use if they are designing, or specifying, a logistics system for a bioenergy plant. Logistics systems have been designed for many agricultural and forest products industries. Thus, it is wise to use the lessons learned in these commercial examples. Each of these industries faces a given set of constraints (length of harvest season, density of feedstock production within a given radius, bulk density of raw material, various storage options, quality changes during storage, etc.) and the logistics system was designed accordingly. Typically, none of the existing systems can be adopted in its entirety for a specific bioenergy plant at a specific location, but the key principles in their design are directly applicable.

Our definition of biomass logistics is “a series of unit operations that begin with biomass standing in the field and ends with a stream of size-reduced material entering a bioen­ergy plant for 24/7 operation”. (One example is shown in Figure 13.1.) All the required

Cellulosic Energy Cropping Systems, First Edition. Edited by Douglas L. Karlen. © 2014 John Wiley & Sons, Ltd. Published 2014 by John Wiley & Sons, Ltd.

unit operations are linked together in this chapter. In general, it is not wise to end the analysis of a logistics chain when a truckload of raw biomass enters the plant gate, as is often done.

The term “feedstock logistics” is used to indicate that the focus is on the movement of raw biomass from the field to a bioenergy plant. This plant may be a “Regional Biomass Processing Depot” (RBPD) as outlined by Eranki et al. [1]. The depots (size range 100­1000 ton/d) are envisioned as locations where raw biomass is received and some prepro — cessing/pretreatment is done to create an intermediate product, or products, that are shipped to a large-scale biorefinery where the final processing is done. The term “biomass logistics” is reserved for the entire logistics chain from field to biorefinery, thus our use of the term “feedstock logistics” for the logistics from field to plant. Throughout this chapter, keep in mind that the “plant” can be an end user or a RBPD.