Application of Hazard and Operability Analysis (HAZOP) Method for Risk Analysis in CGS Station

The hazard and operability study (HAZOP) method is a risk assessment method based on engineering systems used for qualitative analysis or quantitative evaluation. It is mainly used to discover potential hazards and operational difficulties in the design and qualitative stages of chemical systems. The study aims to apply the HAZOP method in process and safety operations at gas depressurization station.

This descriptive study was performed at CGS station. The station was divided into four principal nodes including: filter, heater, regulator, and odorize part. Required information for HAZOP worksheets were gathered by operational procedures, daily reports and interviews with engineers and operators working at the station. To determine the severity of consequences and probability of occurrence of scenarios that were predicted based on the risk matrix, the amount of risk was specified and the necessary suggestions were made in this regard.

According to this study, the operational indicators in the pressure reducing station process included pressure, flow, level and temperature. 22 main deviations and 50 causes of failures were identified. 5 deviations (23%) were in the low risk range (green area) and 17 (77%) were in the medium risk range (yellow area).

  Causes and effects of deviations in operational parameters at four nodes in gas depressurization station were identified by HAZOP. Preventive actions were emphasized, such as consistent inspection of pipelines, preventive and timely maintenance and preparing a well-scheduled plan for inspecting the equipment in terms of corrosion, inspection, and design revision.