Partial energy integration between biofuels production processes: Effect on costs, CO2 emissions and process safety

Abstract

Energy integration is a tool which allows reducing the heating and cooling requirements for production processes. This is particularly important in the processes for production of biofuels, since such processes are expected to have low environmental impact, which can be achieved by reducing the need for steam and cooling water. It is common to perform energy integration by making use of all the available streams. This approach may allow reducing as much as possible utilities’ requirements, but other indicators may be affected, such as capital costs, since the number of required equipment is increased. Thus, in this work the effect of performing partial integration is assessed, i.e., selecting only a few streams to perform the energy integration. The effect of increasing the number of integrated streams is assessed in terms of sustainability indicators based on the green chemistry principles. The studied indicators are utilities’ requirements, total annual cost, environmental impact (assessed through CO2 emissions) and safety (assessed through the HPSI index). The study is applied to the energy integration of a supercritical biodiesel production process and a lignocellulosic bioethanol production process.