(455c) Intensification of Dispersants Production Via Thin Film Evaporation for Simultaneous Reaction and Separation

The chemical industry is currently undergoing a paradigm shift, moving away from decades old conventional processes to highly intensified, modular, and cleaner processes. The development of these new technologies is driven by multiple factors, including the need for reducing energy consumption and hence cost to remain competitive in the market, new and emerging emissions standards to mitigate climate change, new feedstocks while moving from fossil to renewable resources, and safety considerations that scale with the physical footprint of manufacturing facility. The specialty chemicals industry in particular is to-date largely operating large batch reactors of tens to hundreds of thousands of gallons in capacity and could reap significant benefits from a transition from batch to continuous manufacturing.

The present project is investigating the production of succinimide dispersants from poly-isobutylene succinic anhydride (PIBSA) and polymeric amines. The reaction occurs via two a step mechanism, an initial amidation followed by a reversible dehydration step to give poly-isobutylene succinimide as the dispersant product. In a continuous reactor, where the byproduct water from the second step remains in the product stream, the reaction is hence equilibrium limited and requires a downstream drying step to obtain the dehydrated dispersant product at full yield. We had previously identified an agitated thin film evaporator (TFE) as well-suited for drying of the highly viscous product stream.

Based on these prior studies, we now investigated the use of a TFE as a reactive separator, i.e. using the TFE as an intensified unit in which reaction and separation occur concurrently. The TFE was first modeled by integrating our previously developed reaction kinetics with mass and energy balance equations. Appropriate correlations for heat and mass transfer were identified from the literature and verified for our set-up. This performance model confirmed the feasibility of replacing the two step reactor-evaporator system with a single TFE as an intensified reactive separator. The model predictions were then validated experimentally in a next step. Overall, our study confirms that a thin film evaporator could serve as a highly intensified, integrated reactor-separator unit for reactive processing of viscous mixtures in the presence of equilibrium-limitations.