The environmental problem is a priority for Petrobras that has established an ambitious program to reduce the emissions from its refineries.
Petrobras owns 12 refineries operating 13 Fluid Catalytic Cracking Units.
This report identifies Petrobras's best practices in the managing of environmental issues.
Potential sources of environmental impact were analyzed in the majority of the existing cracking units in normal operation and in startups and shutdowns.
Some of the analyzed sources are:
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Particulate, sulphur and nitrogen oxides emissions from the CO boiler or recovery boiler stack.
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Particulate emissions in unit startups.
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Equilibrium catalyst.
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Ash content in fuel oil.
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Sour water streams.
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Spent amines.
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Procedures prior to Equipment liberation for cleaning.
In October of 2000 a work group was created with the task of identifying the best methodologies, technologies and Prevention Practices to Control of Emissions. These procedures will be the base for a Manual of the Best Practices to be adopted for each emission source identified and of an Action Plan for the refineries.
Twenty-six key points were identified with strong environmental impact potential, generating recommendations for the Action Plan to be elaborated by the refineries, as summarized below.
Recommendations IMPACT 1) Particulate emission from the boiler stack for the Refinery Action Plan
Particulate Emissions should be controlled by Operational Management
CO boiler - substitute fuel oil for gas burning
Use of state of the art Cyclones
Evaluation of catalyst losses through the main fractionator by measuring the ash content in the decanted oil
Definition of clear operational limits of variables that can influence catalyst losses IMPACT
2) Catalyst emissions in FCC start-ups
Use of minimum air flow rates in catalyst loading
Definition of the injected steam flow rate to the converter BLOCK 2 - - FORUM 8 93
Definition of operational conditions to reduce catalyst losses through the main fractionator
DCS display of the converter variable limits to control catalyst entrainment IMPACT
3) Particulate emissions from the catalyst storage drum
Use of sleeve filters in the ejector's suction
Use of silencer in the ejector's exhaust line
If possible all catalyst handling procedures should be carried out without using the ejector
All the catalyst gathered from the sleeve filter and the ejector's cyclone has to return to the catalyst storage drum IMPACT
4) E-CAT destination
Prioritize E-Cat use as flushing
Evaluate new options for E-cat use
Residual catalyst from sampling must be transferred to the storage drum
Make a check-list for E-cat transportati