(104bs) Gas Detection Management in Petrochemical Plant

In 2005 Braskem started the project Gas Detection in Basic Petrochemical Unit.

That period were 307 detectors installed in Olefins 1, Olefins 2, Aromatics 1, Aromatics 2 and tanks farm. These are compound of reliable system to detect small leakages around the industrial area and permit a quick response to the problem.

Bases of the project:

• Metodology approved by DNV – Det Norske Veritas, Bureau Veritas (BV), Lloyd´s Register
• CFD model to simulate the location and the main points of leakage;
• Software CFX - dispersion of gases
• Main risk scenarios of Apollo 2 study (322 scenarios)
• MTL Engineering study - based in the clouds to flammable gases generated by the main risk scenarios of plants;

Gas Dispersion Study took into account:

• The gas dispersion study - CFD (Computational Fluid Dynamics).
• The finite volume elements - main construction characteristics (equipment and constructions)
• The calculation was done for different ambient conditions, representing the most critical conditions and the most frequent, where the leakage can occur.
• The leakage conditions were defined considering the process conditions, including composition, flow, temperature and pressure.

The existing architecture of the 307 detectors allows a full scan of the operational area. Thus this means it can be made as to the events management process from the operator panel in the control room together with the field operator.

 

FLAMMABLE GAS DETECTOR - RANGE OF LEL (%)
Registration on shift log book	Registration of causes on shift log book	Registration fo deviation on sap with simple approach investigation	Registration of deviation on sap with complete approach investigation
≥ 5 % and < 20 %	≥ 20 % and < 40 %	≥ 40 % and < 80%	> 80%

The operator panel to verify that there is an alarm; it identifies the location of the detector alarmed and safest route to traverse the field operator to go check if there is any leakage at the site or any task that may have caused the alarm detector. This approach allows of detecting anomalies in the process early and taking corrective action in advance.

The record of nonconformities flammability according to table above allows us to understand the causes and track events with potential to larger leaks, minimizing the occurrence of events with consequences more relevant to the integrity of operating process area.