Enclosed modules, explosion pressure and operational challenges with intense cold. Liv Ranveig Rundell, Technical Safety Petroleum Safety Authority

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1 Enclosed modules, explosion pressure and operational challenges with intense cold Liv Ranveig Rundell, Technical Safety Petroleum Safety Authority

2 Agenda Project «Enclosed modules design and explosion pressure» Background and objective Explosion/Fire in enclosed modules Barrier analysis Risk mitigating measures Conclusion Project in Operational challenges with intense cold Source: Safetec

3 Background and objective Arctic regions can lead to design of the installation with enclosed modules Provide knowledge related to: Gas leakages and explosion pressure in enclosed modules. Fire in enclosed modules. Risk mitigating measures regarding design of process modules.

4 Reduced ventilation Enclosed module = Mechanical ventilated module (NORSOK requirement: minimum 12 air changes per hour) Figure: the probability of a given number of air changes per hour in a natural ventilated module with significant extent of enclosure. Module has an average of ca. 130 air changes per hour. Source: Safetec

Gas leakages and explosion pressure High frequency of leakages for rates <1 kg/s Leakage rates < 1 kg/s can generate large combustible gas clouds: Increased explosion pressure Higher probability of

5 Gas leakages and explosion pressure High frequency of leakages for rates <1 kg/s Leakage rates < 1 kg/s can generate large combustible gas clouds: Increased explosion pressure Higher probability of ignition Increased explosion risk Explosion risk: increased probability for explosion pressure exceeding design criteria of the explosion walls. Enclosed modules reduced reduction of explosion pressure Source: Safetec

6 Effect of ventilation size of gas cloud Maintenance of ventilation on confirmed gas detection Reduced size of combustible gas cloud for leakages <1 kg/s. Small modules: leakage rates of 0,1 kg/s can generate large combustible gas clouds. Leakage rate Small module Medium module Large module 630 m m m 3 No ventilation Ventilation maintained No ventilation Ventilation maintained No ventilation 0,1 kg/s % < 1 % < 1 % < 1 % < 1 % 0,75 kg/s % % % % % Table - maximum extent of combustible gas cloud shown in %

7 Early gas detection Combustible gas cloud developes faster in enclosed modules. Extent of combustible gas explosion if ignited Gas with a concentration >20 % LEL gas which can be detected and initiate actions Source: Safetec Important to detect leakages before: a combustible gas cloud has developed. ignition sources are exposed. Detection of gas leakage initiate actions: Igniton source control Process isolation Depressurisation

8 Fire in an enclosed module Fire (no explosion prior to the fire/explosion panels are intact) Ventilation controlled reduced heat loads Fire following an explosion. Controlled by the amount of available combustible material higher heat loads Source: PPGPMC

9 Barrier analysis Enclosed modules Negative effect on barriers: Ventilation Structural integrity Emergency power Source: PSA

Risk mitigating measures Risk mitigating measures can be: Good layout to minimize explosion loads Design solutions which reduces the probability of leakage Fast and reliable

10 Risk mitigating measures Risk mitigating measures can be: Good layout to minimize explosion loads Design solutions which reduces the probability of leakage Fast and reliable gas detection Release of fire water on confirmed gas detection Sectioning of hydrocarbon process and fast depressurisation Reliable and effective explosion panels Source: Safetec

11 Conclusion Open module: Preferred solution both for safety reasons and cost. Enclosed module: Leakage rates < 1 kg/s can generate large combustible gas clouds Explosion risk is significantly increased. Risk mitigating measures is necessary. Source: Safetec

12 Operational challenges with intense cold Project kick off 2018 Identify operational challenges with regards to: Fire water systems in intense cold. Process systems including support systems in intense cold. Report expected 4Q 2018 Plan to publish report on PSA website 1Q 2019

13 Report (Safetec) can be downloaded from: Thank you for your attention

MODULAR INTEGRATION OF PROCESS EQUIPMENT PACKAGES FOR OIL AND GAS FACILITIES

MODULAR INTEGRATION OF PROCESS EQUIPMENT PACKAGES FOR OIL AND GAS FACILITIES Copyright Material PCIC Europe Paper No. PCIC Europe LO-70 Allan Bozek EngWorks, Inc. 1620 49 th Avenue, SW Calgary, AB T2T