CHEMICAL ENGINEERING TRANSACTIONS VOL. 77, 2019 A publication of The Italian Association of Chemical Engineering Online at www.cetjournal.it Guest Editors: Genserik Reniers, Bruno Fabiano Copyright © 2019, AIDIC Servizi S.r.l. I SBN 978-88-95608-74-7; I SSN 2283-9216 Use of LOPA and HAZOP Concepts for Complex Automated Hazard Identification Matej Danko, Ján Janošovský, Juraj Labovský, Zuzana Labovská, Ľudovít Jelemenský* Institute of chemical and environmental engineering, Faculty of chemical and food technology, Slovak university of technology, Radlinského 9, 81237, Bratislava, Slovakia ludovit.jelemensky@stuba.sk In this contribution, integration of bifurcation and steady state analysis into simulation-based hazard and operability study – HAZOP is presented. In this study, advanced mathematical modeling techniques provide valuable support to testing of processes design and process control on different HAZOP deviations. Raw process design together with basic process control is presented as the first layer of protection within general Layer of protection analysis (LOPA). Protection layers are tested by a set of dynamic simulations on different failures. The concept is able to identify hazardous regimes caused by parameter disturbances themselves and also those when inappropriate control loop actions act synergic with already present disturbances. Thus, validation of the applied process control is provided. In this work, CSTR propylene glycol production under Proportional-Integral-Derivative (PID) actions was chosen to identify potential hazard and operability problems of a real chemical process. 1. Introduction Hazard and operability (HAZOP) study is a team-based brainstorming activity that systematically reviews all equipment as well as deviations from their normal operating conditions in order to identify potential safety related hazard in chemical plant. The latest overview of recent developments including support by CAPE (computer aided process engineering) methods and combination of HAZOP with other PHA has been provided by Pasman and Rogers, (2016). The prime drawback of a HAZOP study is related to the possibility that hazards and operability problems may be overlooked as they did not occur in the past. Application of the HAZOP technique to a detailed chemical plant design is a complex and time consuming task. Both of these drawbacks can be reduced by integration of a simulation-based approach, mathematical modeling and other risk assessment techniques into HAZOP (Antonello, et al., 2016). Several simulation tools such as Aspen Plus, Aspen Hysys, Unisim Design are available offering basic environment for the simulation of a number of deviations from design intent. However, different attempts to combine commercial process simulation features with standard hazard identification techniques often show strong limitations of the simulation of processes operated near or within nonlinear regimes, especially in the absence of numerical solution convergence (Li and Huang, 2011 and Janošovský, et al., 2016). To be rigorous, control and regulation systems have to be also integrated into the simulation environment. Basic process control is the first of various protection layers used to lower the frequency of undesired consequences (AICHE, 2001). LOPA provides a consistent basis for judging whether there are sufficient IPLs (Independent Protection Layers) to control the risk of an accident for a given scenario. However, control system mechanisms as well as other present safeguards unpredictably affect the propagation of disturbances mainly within the nonlinear behavior regimes of the process. Simulating only the process design in steady state together with the implemented process control layer on generated HAZOP deviations can result in situations when it is impossible to distinguish consequences caused by the parameter disturbance itself from those caused by inappropriate process control action. Also, traditional HAZOP studies often focus only on the size of the generated deviation and they do not consider duration of the deviation and the failure dynamic behavior, as it is not the purpose of steady state process design DOI: 10.3303/CET1977135 Paper Received: 3 December 2018; Revised: 11 April 2019; Accepted: 4 July 2019 Please cite this article as: Danko M., Janosovsky J., Labovsky J., Labovska Z., Jelemensky L., 2019, Use of LOPA and HAZOP Concepts for Complex Automated Hazard Identification, Chemical Engineering Transactions, 77, 805-810 DOI:10.3303/CET1977135 805