Design and Control of Reactive Distillation Process for the Production of Methyl Valerate

Abstract

Methyl valerate (VAME), also known as methyl pentanoate, is a methyl ester of pentanoic acid (valeric acid). VAME is usually used as a fragrance in the production of beauty care, soap, and laundry detergents. High purity VAME can also be used as a kind of plasticizer. This study presents design details of the process for the manufacture of VAME. A reactive distillation column (RDC) is used in the production process to overcome equilibrium limitation of the esterification reaction. There is no bottom outlet of this RDC. Both products, VAME and water, are withdrawn from the distillate of RDC and then can be separated by two strippers and a decanter. A thermally coupled design is then developed to reduce the remixing effect in the rectifying section of the RDC. The simulation results show that 30% energy saving can be achieved by using the proposed thermally coupled configuration, but only 17% of total annual costs can be saved due to the use of a compressor. Control strategies of both conventional and thermally coupled configurations in neat design are investigated. The simulation results show that a thermally coupled configuration can reject disturbances faster with smaller steady state deviations from the specifications of the VAME product.

Process Development, Assessment, and Control of Reactive Dividing-Wall Column with Vapor Recompression for Producing n-Propyl Acetate

“…In their control strategy, the feed ratio is manipulated by the sensitive tray temperature of the RD column; however, the reflux rate of the RD column is ratioed to the sum of the two feed flow rates (F L /SF) instead of the fixed β L . Their results demonstrate that the product purities can be controlled at their respective specifications with smaller offsets using both control schemes with fixed β L or F L /SF; however, relatively large transient deviations occur in the dynamic responses of the product purities for the control strategy proposed by Chen et al 49 By referring to the previous relevant works, 48,49 the sensitive tray temperature of the RD column of RDWC is used to manipulate the molar flow rate ratio of the n-propanol feed to acetic acid feed (F R ), while the sensitive tray temperature of the product column of RWDC is used to manipulate its reboiler duty (Q R-PC ). The open-loop sensitivity analysis is implemented to select the sensitive tray temperatures of the RD and product columns by introducing ±0.1% step change in each manipulated variable while keeping the others at their nominal steady-state values.…”

“…In their control strategy, the feed ratio is manipulated by the sensitive tray temperature of the RD column; however, the reflux rate of the RD column is ratioed to the sum of the two feed flow rates ( F L /SF) instead of the fixed β L . Their results demonstrate that the product purities can be controlled at their respective specifications with smaller offsets using both control schemes with fixed β L or F L /SF; however, relatively large transient deviations occur in the dynamic responses of the product purities for the control strategy proposed by Chen et al…”

“…48 proposed a control structure for a thermally coupled RD process for the esterification of acetic acid and isopropanol, wherein the feed ratio is manipulated by the sensitive tray temperature of the RD column while β L is fixed. Chen et al 49 investigated the control performance of a thermally coupled RD process for producing methyl valerate. In their control strategy, the feed ratio is manipulated by the sensitive tray temperature of the RD column; however, the reflux rate of the RD column is ratioed to the sum of the two feed flow rates (F L /SF) instead of the fixed β L .…”

“…By referring to the previous relevant works, , the sensitive tray temperature of the RD column of RDWC is used to manipulate the molar flow rate ratio of the n -propanol feed to acetic acid feed ( F R ), while the sensitive tray temperature of the product column of RWDC is used to manipulate its reboiler duty ( Q R‑PC ). The open-loop sensitivity analysis is implemented to select the sensitive tray temperatures of the RD and product columns by introducing ±0.1% step change in each manipulated variable while keeping the others at their nominal steady-state values.…”

Process control in intensified continuous solids handling

“…In general, the higher degree of integration will make the process more challenging to control and will perhaps restrict the implementation of highly intensified processes in industry [7]. Many of the published works on control design for intensified processes deal with reactive distillation (see, e.g., [10,[13][14][15]), but reported work in the area of solids 1 http://ibd-project.eu/…”