The use of modular plants in the chemical industry is expected to make the structure of supply chains more dynamic. The models currently used to get insight in supply chains assume a predefined supply chain structure, as orders are exogenously defined. Consequently, those models cannot grasp the dynamic nature of supply chains with modular plants. In this paper a market conceptualization based on agent-based computational economics is presented that includes transport costs in the negotiations and enables the modeling of supply chains as structures that emerge from market dynamics. It is shown that this conceptualization can capture the market dynamics that are needed to simulate a dynamic supply chain.