Energy-Efficient Design of an Ethyl Levulinate Reactive Distillation Process via a Thermally Coupled Distillation with External Heat Integration Arrangement

Abstract

In this paper we describe an energy-efficient process design using a reactive distillation (RD) of the esterification reaction for the synthesis of ethyl levulinate (LAEE). Two designs, a neat design and an excess design, were examined to find the best configuration for the process. In the neat design, there are two columns with equal molar feeds to produce LAEE. An additional column is required in the excess design to separate LAEE from the unreacted reactant (levulinic acid, LA). Later in the process, this unreacted LA is recycled back into the RD column. Compared to the neat design, the excess design showed superiority for the esterification process in terms of the total annual cost (TAC) and energy requirement. Therefore, three energy integration configurations, external heat integration (HI), thermally coupled distillation (TCD), and a combination of TCD and HI, were investigated in this excess design. A side reboiler was implemented in the water removal column to overcome the limitation of the temperature difference for heat transfer. The simulation results showed that the configuration of TCD with HI was the best one, which saved 32.9% and 10.5% of the energy and TAC, respectively, compared to the conventional RD with three columns without HI.

Optimally designed reactive distillation processes for eco‐efficient production of ethyl levulinate

“…The results obtained in this work are different than reports of other authors . The contrasts are explained by the fact that the implementation of a multi‐objective optimization algorithm needs some adjustments to the rigorous process simulation.…”

“…An excess of LA is actually used owing to the recycle of unreacted LA (in addition to the continuous reflux of LA). Excess operation was proved to perform better than neat operation . The first separation column (RC‐1) performs the separation of water by‐product as distillate from the main product (EL) and the unreacted LA.…”

“…This work is the first to present optimally designed RD processes (including thermal coupling) for EL production, taking into account several key aspects for optimization: total annual cost (TAC), environmental impact (Eco‐indicator 99) and process safety (individual risk). To allow a fair comparison, some of the topology of the RD processes is based on previous work reported recently (but focused on economics only), while others are new (e.g. based on RD and dividing wall column (DWC) technology).…”

Design of an Intensified Reactive Distillation Configuration for 2-Methoxy-2-methylheptane

“…was assumed, (2) the catalyst Amberlyst 35 occupies half of a reactive tray, and (3) the downcomer occupies 10% of the tray area. 16 With these assumptions, the diameter of the column was then determined using eq 6 to accommodate this catalyst per tray. The column diameter is estimated as 3.90 m using a bulk density of 800 kg/ m 3 .…”

“…Meanwhile, the bottom stream originating from column C2 was introduced to the hot side while the vapor boilup stream originating from the RD column was introduced to the cold side of the shell and tube zones of heat exchanger HEX-1. The heat exchanger area was required to be maintained at 16.54 m 2 . The reboiler duty could be reduced from 1.34 MW to 0.98 MW.…”