حامد نوروزي

Propylene is one of the most important petrochemical key raw materials. Its growing market has made its traditional production methods inadequate, and propane dehydrogenation as one of the novel methods of its production has been widely adopted. Oleflex technology is the preva‎lent propane dehydrogenation technology, and there are units in Iran that are being developed using it. This technology is selected as the subject of this study. As there are no comprehensive studies about the process safety aspects of this technology on an industrial scale, a fundamental process safety approach which is Inherently Safer Design (ISD) is used as the approach to analyze this unit. Among different ISD methods, the Comprehensive Inherent Safety Index (CISI) as a competent and inclusive method was used to carry out the analysis. CISI results portray a relative ranking of sub-units and equipment in the unit that can be used as a road map in the process design life cycle to gain more focus on the more hazardous elements. The results of this method have been compared and verified with other methods such as Dow F&EI. The equipment found to be more hazardous were further analyzed in detail by Hazard and Operability (HAZOP) study and the intense scenarios that were found to be plausible as results of process deviations were extracted. An index to predict the inherent risk of the equipment in the process was introduced. Anticipated Inherent Risk Index (AIRI) ranks equipment upon extracted scenarios using consequence modeling and failure frequencies in a simple way. Results of this research show that in the main sub-units, the Propane-Propylene distillation system (24% of the whole unit’s CISI weight), Depropanizer distillation system (10%), combined feed heat exchanger (2%) on the inlet of the reactor system, and the dryer on the outlet of the product preparation system (1%) are the most inherently hazardous equipment in their subunits upon CISI. AIRI results for the scenarios of these parts show that the dryer on the outlet of the product preparation system, propane recycle pump in the Propane-Propylene distillation system, Depropanizer tower, and the Propane-Propylene separation tower have the highest risk indexes, respectively, for the selected scenarios.

هيدروژن‌زدايي از پروپان , طراحي ذاتاً ايمن‌تر , سنجه ايمني ذاتي , ارزيابي كمّي ريسك اولويت‌بندي‌شده , ايمني فرايند

Propane Dehydrogenation , Inherently Safer Design , Prioritized Quantitative Risk Assessment , Inherent Safety Metrics , Process Safety

Hamed Norouzi

Mohammad Amin Sobati, Soroush Baradaran