A decision support tool for strategic planning of sustainable biorefineries

In this paper we formulate, implement, and test a model for technology and product portfolio design for a multi-product multi-platform biorefining enterprise. The model considered is an MILP financial planning model with the objective of maximizing the stakeholder value. Integer variables are used to select appropriate feedstocks, technologies, and products, material and capacity balances are used to design capacity and set production targets, while cash balances are used to describe investment and operations financing. Stakeholder value is described as the shareholder value with monetized environmental implications in terms of emissions mitigation costs and credits. Process integration schemes utilizing emissions are considered to reduce the emissions load and add to the bottom-line. A preliminary process design and product portfolio is provided as a result. Advantages of process integration are quantified using a central utilities facility and effluent recycles. Sensitivity analysis is conducted to determine important parameters that shape the objective function.