(337da) Batch-to-Continuous Transition in Specialty Chemicals Industry: Intensified Dispersants Production

Specialty chemicals are to-date largely produced in large batch reactors with typical volumes of tens to hundreds of thousands of gallons. While these batch processes are simple to operate, they are also notably inefficient compared to the current state of technological advancement. Significant opportunities exist to enhance cost, energy, and atom efficiency, while reducing the environmental footprint of these processes. Consequently, the industry is shifting from traditional manufacturing methods to intensified, modular, and cleaner approaches.

The succinimide family of dispersants, as part of specialty chemicals segment, serves various industries including automotive, hydraulic fluids, and metalworking, and are till-date produced using large volume (~10k-50k gal) batch reactors with long batch times (~6-10 hr). Among these, Polyisobutylene succinic anhydride (PIBSA)-based dispersants are highly efficient in preventing sludge and deposit formation, making them a key component in automobile engine oils. They are formed by a two-step reaction between PIBSA and polyamines: amination reaction to form a PIB-succinamide intermediate, followed by slow dehydration step to yield the PIB-succinimide product. In the first phase of the work, robust reaction kinetics were acquired, and a batch-to-continuous transition was demonstrated using a combination of tubular reactor and a thin film evaporator (TFE) system. Further intensification of the process was achieved by utilizing (TFE) as a standalone reactive separator.

The second phase of the work focuses on back-integration of the process, as the reactant, PIBSA, is still produced using large volume batch reactors. This hinders the overall process from realizing the full benefits of continuous process operation. The production of PIBSA occurs via reaction of polyisobutylene (PIB) with maleic acid anhydride (MAA) and poses several challenges for continuous processing viz., i) highly viscous and poorly miscible reactants; ii) slow kinetics at typical operating conditions which result in long reaction times (>10 hours) and hence require operation at elevated temperature and pressure conditions (T>200C, P>250 psig); and iii) undesired side reactions of MAA due to its thermal instability and high sensitivity to basic functionalities. We address these issues via use of a suitably designed high-pressure, high-temperature continuous as well as batch reactor systems; improving mixing via emulsification with the reaction product, PIBSA; this in turn also mitigates undesired solids formation to improve product yield.

This work showcases the potential of transitioning from batch to continuous process operation for large-volume chemical commodities within the specialty chemicals industry, using the PIBSA-based dispersants family as a model system.

Research Interests

1. Engineering efficient and sustainable processes: My primary focus is on developing efficient and cleaner processes across diverse class of reaction and separation systems. I have keen interest in understanding the fundamental chemistry and transport phenomena that underpin these processes, guiding their development.
2. Novel reactor and heating concepts: I am dedicated to exploring cutting-edge reactor technologies, such as cavitation reactors, catalytic membrane reactors, and electrochemical flow reactors to name a few. Additionally, I am keen on investigating selective heating methods like microwave, and induction heating.

• Technology commercialization and scale-up: My interests extend to evaluating the feasibility of commercialization using techno-economic analysis. I am also enthusiastic about leading initiatives for scale-up through modeling and pilot testing.

Keywords: process development, process intensification, specialty chemicals, batch-to-continuous transition, thin film evaporator, continuous reactor, batch reactor, dispersants.