engleski

Nitric Acid Revamp and Upgradingof the Alarm & Protection Safety Systemat Petrokemija, Croatia

Every industrial production, particularly chemical processing, demands special attention in con-ducting the technological process with regard to the security requirements. For this reason, pro-duction processes should be continuously monitored by means of control and alarm safetyinstrumented systems. In the production of nitric acid at Petrokemija d. d., the original alarm safe-ty system was designed as a combination of an electrical relay safety system and transistorizedalarm module system. In order to increase safety requirements and modernize the technologicalprocess of nitric acid production, revamping and upgrading of the existing alarm safety systemwas initiated with a new microprocessor system. The newly derived alarm safety system, SimaticPCS 7, links the function of “classically” distributed control (DCS) and logical systems in a com-mon hardware and software platform with integrated engineering tools and operator interface tomeet the minimum safety standards with safety integrity level 2 (SIL2) up to level 3 (SIL3), accor-ding to IEC 61508 and IEC 61511. This professional paper demonstrates the methodology ofupgrading the logic of the alarm safety system in the production of nitric acid in the form of a logi-cal diagram, which was the basis for a further step in its design and construction. Based on thementioned logical diagram and defined security requirements, the project was implemented inthree phases: analysis and testing, installation of the safety equipment and system, and commis-sioning. Developed also was a verification system of all safety conditions, which could be appliedto other facilities for production of nitric acid. With the revamped and upgraded interlock alarmsafety system, a new and improved safety boundary in the production of nitric acid was set, whichcreated the foundation for further improvement of the production process in terms of improvedanalysis.

Nitric acid production ; alarm safety system ; revamping

nije evidentirano