This paper discusses the relation between software tools primarily designed for 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 mono-propylene glycol with consecutive reactions producing higher glycols) in two continuous-stirred tank reactors (CSTRs) in series with jacket cooling was used. In the first section a mathematical model of two CSTRs in series was formulated. 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 for utilization of these results in HAZOP studies.

The design of chemical reactors, especially the safety design process, requires basic knowledge of all particular processes proceeding in the reactor, and their influence on the reactor behaviour. A useful tool for safety analysis is a mathematical model of the reactor. By simulation of its performance one can reveal the real reactor behaviour. In the present paper, we tried to formulate and discuss the guidelines for safety analysis of a chemical reactor. In this article, a homogeneous CSTR was assumed, but some considerations could be extended for other types of homogeneous reactors. A program tool using nonlinear analysis of the studied system is presented.

Exothermic reactions are the most interesting systems for safety analysis because of their potential safety problems and the possibility of exotic behavior such as multiple steady states. A sensitivity analysis of an exothermic reaction involving the hydrolysis of propylene oxide to propylene glycol in a CSTR with jacket cooling is presented here. The objective of this article is to determine how multiple steady states might arise. A comparison of the static and continuation method of the identification of multiple steady states and their stability is presented. Finally, the implications of safety analysis for operation and control of reactors with multiple steady states are discussed.

The safety analysis of an exothermic reaction was conducted in order to investigate potential safety problems and the possibility of abnormal behaviour such as multiple steady states. The bifurcation analysis was made for. the hydrolysis of propylene oxide to monopropylene glycol with consecutive reactions producing higher glycols in a CSTR with jacket cooling. Failures in the feed flow rates of propylene oxide and cooling medium were simulated and discussed, and control strategies were proposed. The knowledge of the stability of the dynamic behaviour of CSTR was demonstrated to be beneficial for an effective reactor operation and control.

In the paper is presented the design of a separation column for recovery of 1,2-dichloropropane (DCP) from the off-gas released during propylenechlorhydrine (PCH) synthesis. The aim of this separation is to recover DCP with a purity of 99.99 mass%. The simulation of the separation column is performed by means of the professional simulation program HYSYS. The design of the rectification column is based on complete experimental measurements. The calculation is compared with the design of a separation column, which uses for the computation of the equilibrium composition the corresponding database of the simulation program, and with the calculation, in which the complete set of equilibrium data is predicted from the UNIFAC method. By comparison of the results of the rectification column design quite different values of parameters which characterising the rectification column (i.e. reflux ratio, flows and composition of phases on the stages…) were obtained. These could lead to false results in designing the equipment. Within the frame of this work experimental vapour–liquid equilibrium (VLE) data at a pressure of 98.66 kPa and binary solubilities are presented for the system composed of following components: water, propylene oxide (PO), propanal (PA), and DCP. The dependence of activity coefficients on the composition is given by the UNIQUAC equation. The experimental results are compared with those predicted by means of the HYSYS database and with those predicted from the UNIFAC method.

Interest in discovering multiple steady-state solutions for reaction processes grew exponentially by the existence of the first computers. Modern process simulators can find multiple solutions only by the expenditure of much effort. Three mathematical models with different accuracy are introduced and a simple comparison of model's accuracy is made with regard to safety analysis of continuous stirred tank reactor. The first two models are based on standards in chemical reactor design; the third one is an internal model of CSTR in HYSYS simulation program. Furthermore, OLE automation interface is also used to access the existing physical property packages of HYSYS.