Steady States Analysis and Dynamic Simulation as a Complement in the Hazop Study of Chemical Reactors

Abstract

his paper discusses the relation between software tools primarily designed fbr mathematical modelling, simulation and investigation of chemical reactors and the common method for identification of hazard, the Hazard and Operability (HAZOP) study. We have tried to couple these tools with the HAZOP study. The principal objective was to present a new methodology for hazard investigation. In our work a multi-parameter analysis of a model system with exothermic reaction (hydrolysis of propylene oxide to monopropylene glycol with consecutive reactions producing higher glycols) in two continuousstirred tank reactors (CSTRs) in series with jacket cooling was used. In the first section a mathematical model of two CSTRs in series was fbrmulated. The next step is safety analysis, including analysis of the multiplicity of steady states and their stability, study of safe operating, and conditions and trajectories, which can shift the reactors from one steady state to another steady state. Parametric studies of the failure of the reactants flow rate (propylene oxide and water) and of the cooling medium were also done. Finally, the results of safety analysis were reproduced and we tried to find all possibilities fbr utilization of these results in HAZOP studies.

Hazard and operability (HAZOP) analysis. A literature review

“…Lawley [8] defined and delineated the principles needed to carry out operability studies and hazard analysis due to the increasing complexity of new processes that could not be examined thoroughly using the then-conventional approaches based on equipment-oriented practices. Indeed, the requirement for having process-oriented methods [161][162][163][164][165][166] 3.6 of examination was the reason for the generation of HAZOP. Lawley's paper defines the planning, execution, and treatment of the operability study.…”

“…This methodology's purpose is to determine risk from operational disturbances, and to develop means for effective risk reductions [161]. Svandova et al [162] recently suggested complementing HAZOP studies with simulations.…”

A New Homotopy-Based Strategy for the Robust Determination of All the Feasible Solutions for CSTR Systems

“…The field continues to receive some attention through the introduction of more complex CSTR systems (see e.g. Mjalli et al [2]; Švandová et al [3]; Kiss et al [4]; Brooks [5]; Yermakova and Anikeev [6]; Waschler et al [7]). However, the emphasis in the current studies in the literature has shifted towards the investigation of CSTR systems from the perspective of numerical solving methods [8][9][10][11][12].…”

“…in CSTR cascades [2][3], CSTR-recycle systems [22], CSTR-separator-recycle systems [4][5], and in two-phase CSTRs [6][7].…”

Combining HAZOP with dynamic simulation—Applications for safety education

“…The use of steady-state analysis and dynamic simulation as a complement in the HAZOP study of chemical reactors has been suggested recently by Svandova, Jelemensky, Markos, and Molnar (2005).…”