Safety enhancement by transposition of the nitration of toluene from semi-batch reactor to continuous intensified heat exchanger reactor

• Published in: Chemical engineering research & design Vol. 94; pp. 182 - 193
• Main Authors: Di Miceli Raimondi, N., Olivier-Maget, N., Gabas, N., Cabassud, M., Gourdon, C.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2015; Elsevier
• Subjects: Chemical and Process Engineering; Chemical engineering; Chemical Sciences; Engineering Sciences; Failure; Failure scenarios; Fluid dynamics; Fluid flow; Fluids; Heat exchangers; Heat-exchanger reactor; Nitration; Process intensification; Reactors; Safety; Simulation; Stirring; Heat-exchanger reactor; Nitration; Process intensification; Safety; Failure scenarios; Simulation
• ISSN: 0263-8762; 1744-3563
• DOI: 10.1016/j.cherd.2014.07.029

•Nitration of toluene in a continuous compact heat exchanger reactor is carried out.•A safety analysis is conducted to compare continuous and semi-batch processes.•The failures that can lead to thermal runaway are identified using HAZOP method.•The failure scenarios leading to the most dramatic consequences are simulated.•The thermal behaviors of both processes during failure are observed and compared. The behavior of a continuous intensified heat exchanger (HEX) reactor in case of process failure is analyzed and compared to the behavior of a semi-continuous reactor. The nitration of toluene is considered as test reaction to identify the main failure scenarios that can lead to thermal runaway in both processes using the HAZOP method. No flow rate of process fluid and utility fluid in the continuous process. No stirring during feeding of the reactor followed by normal stirring for the semi-continuous reactor. These scenarios are simulated for both processes and the temperature profiles are observed. This study shows that the temperature is better controlled in the continuous process because of the intrinsic characteristics of the HEX reactor. In fact, this device has a low reactive volume relative to the mass of the reactor, allowing a good dissipation of the heat produced by the reaction, even in case of failure. This characteristic of the intensified reactor is confirmed by an experimental work.