Development and implementation of integrated biomass supply analysis and logistics model (IBSAL)

Abstract

This paper describes the framework development of a dynamic integrated biomass supply analysis and logistics model (IBSAL) to simulate the collection, storage, and transport operations for supplying agricultural biomass to a biorefinery. The model consists of time dependent events representing the working rate of equipment and queues representing the capacity of storage structures. The discrete event and queues are inter-connected to represent the entire network of material flow from field to a biorefinery. Weather conditions including rain and snow influence the moisture content and the dry matter loss of biomass through the supply chain and are included in the model. The model is developed using an object oriented high level simulation language EXTEND™. A case of corn stover collection and transport scenario using baling system is described.

Introduction

Recent advances in computational tools have made it possible to build mathematical models for analysis and optimization of complex supply systems. These tools are applied successfully to manufacturing, transportation, and supply chain management of many goods and services. This paper describes the implementation of these tools for simulation of supply and transportation of agricultural biomass. The agricultural biomass supply logistic consists of multiple harvesting, storage, pre-processing, and transport operations. The entire network operates in space and time coordinates. Agricultural biomass supply logistics are characterized by a wide areal distribution of biomass; time and weather-sensitive crop maturity; variable moisture content; low bulk density of biomass material and a short time window for collection with competition from concurrent harvest operations. An optimized collection, storage and transport network can ensure timely supply of biomass with minimum cost.

Tatsiopoulos and Tolis [1] evaluated the supply of cotton gin waste to small decentralized combined heat and power plants in Greece. Hansen et al. [2] developed a simulation model of sugar cane harvest and mill delivery in South Africa. Nilsson [3] described in detail the development of a simulation model (SHAM—Straw Handling Model) for baling and transporting wheat straw to district heating plants in Sweden. The simulation demonstrated the utility of systems analysis in predicting the amount and cost of biomass supply in optimum resource allocation to minimize bottlenecks. Nilsson's published model did not include bulk handling of biomass [4], [5]. Mantovani and Gibson [6] modelled a collection system for corn stover, hay, and wood residues for ethanol production using the GASP IV simulation program. They considered historical weather data and farmers’ changing attitude towards harvesting biomass. They highlighted the impact of weather variations and late harvest on biomass availability and equipment cost. Arinze et al. [7] and Sokhansanj et al. [8] modelled the changes in quality of potash fertilizer and alfalfa cubes, respectively, during storage and transport. The models considered weather data on timeliness of transport operations for these products but did not consider the entire supply chain.

Biomass Technology Group (BTG) [9] recommended a system analysis approach for reducing the costs, energy flow, and emissions of biomass operations. Berruto and Maier [10] and Berruto et al. [11] used a discrete simulation model to investigate how queue management could help to improve the performance of a country elevator receiving multiple grain streams with a single unloading pit. Humphrey and Chu [12] analysed the procurement and processing of corn in a wet milling operation using the simulation language GASP IV. Benock et al. [13] developed a GASP IV-based simulation model to analyse harvesting, on-farm transportation, and drying of corn. The model predictions agreed well with observations. Nilsson [4] and Hansen et al. [2] used the modelling language SIMAN. Rotz et al. [14] developed the dairy forage system model (DAFOSYM) based on the FORTRAN and BASIC languages.

The overall goal of this paper is to simulate the flow of biomass from field to a biorefinery. The specific objectives of this paper are:

• Develop a framework for a dynamic Integrated Biomass Supply, Analysis and Logistics model (IBSAL).

• Model climatic and operational constraints that have significant influence on the availability of biomass to a biorefinery.

• Develop a model to quantify resource allocations (such as labour, equipment and structure) for biomass supply and transport operations, and calculate biomass delivered cost ($ Mg⁻¹). Note that biomass delivered cost in this study do not include any payment to the farmer or farming cost.

• Show the operation of the model with a case study of corn stover supply to a biorefinery.