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Occupational Hygiene in the Oil & Gas Industry Day 4 – Section 17 Design & Review. Summary. Design Review Design Issues For Upstream & Downstream Sites Noise Ventilation Ergonomics Sample points. Hierarchy of Control. Elimination - Best Substitution Engineering Controls
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Occupational Hygiene in the Oil & Gas Industry Day 4 – Section 17 Design & Review
Summary Design Review Design Issues For Upstream & Downstream Sites Noise Ventilation Ergonomics Sample points
Hierarchy of Control • Elimination - Best • Substitution • Engineering Controls • Administrative Controls • Personal Protective Equipment (PPE) – Least effective
Design Information P&I • Current detailed description of the project. • Flow diagrams of the process (including material balance information) • Chemical components to be used. • Volumes of feed stock, raw materials, catalysts, additives, • Production rates, by-products and intermediates • Complete inventory of ‘chemicals/materials’ • Materials used and produced (including products, intermediate streams, feed stocks, catalysts, process additives, etc.)
Design Information – Operations-1 • Information regarding process • Sampling and process control requirements, • Frequency of catalyst regeneration/skims/change-outs; • Process stream sample points should be easily accessed. Closed loop sampling methods should be considered for materials which are particularly toxic (Benzene), or high vapour pressure (e.g. liquefied gases). • Enclosed sample points for corrosive materials • Some of this information can be obtained from the P&I (Process and Instrumentation) diagram.
Design Information – Operations-2 • Information on equipment. • Chemicals are often added to the process through mixing drums or hoppers. • When? How? Who? • These may require local exhaust ventilation, depending on hazardous properties of material to be added, likelihood that the operator will be exposed to the material, and the frequency and duration of the task • Review Standard Operating Procedures • Noise levels (manufacturer’s data)
Design Information – Operations-3 • Wastes and sludge generated, • Storage, Sampling • Removal methods. • Potential releases to air and water should be identified. • Releases to atmosphere from safety relief valves, vents and stacks should be at a safe location. • Vent and safety valve releases are often most effectively controlled when directed to a flare system
Design Information – Operations-4 • Environmental Controls • Reviewed against new and proposed regulations, and changes incorporated. • For example, a new environmental regulation regarding fugitive emissions from valves will impact on the project design; more stringent water quality standards may require additional water treatment processes.
Design Information – Operations-5 • Safety Equipment in the field • Need for deluge showers/eye wash stations • Breathing Apparatus (SCBA) stations • Amenities, change rooms, shower and decontamination facilities • Continuous monitoring systems • Personal monitors – e.g. H2S • Other sources of information. • Regulatory impact statements often required by legislators prior to project approval.
Review Understand the project Understand the process Understand the reactions What are the people (operators, maintenance, contractors) doing? What are the wastes, emissions? What are the environmental controls?
Basics Understanding the process • Carbon Numbers • Some Process Reactions
Carbon Numbers = number of carbon atoms in the molecule
Dehydrocyclization CAT = Catalyst R+0 = Research Octane Number (RON) with no lead
Review – Isom Unit Understand the project – Isom unit is to be added to existing refinery operations Understand the process – Isom Process Understand the reactions – Isom reaction What are the people (operators, maintenance) doing? What are the chemicals used?
Isomerization Process Desulfurized Feed Organic Chloride Make-up Gas HCl Recovery HCl Stripper Hydrogenation Neutralizer Product
Issues to consider • Hydrogen Gas – wide flammability range • Organic Chloride • Hydrogen chloride – potential release • Neutralising solution - & waste handling • Flammability and potential exposure to light hydrocarbons • Insulation materials used in the heater • Noise - heater, compressor, pumps etc. • Sample points for feed, intermediates, product
Review - Gas Plant • Understand the project – Gas plant to separate refinery ‘light ends’ C1 to C6 • Understand the process – P&I • Volumes • Composition • Understand the reactions – Fractionation • What are the people doing? (operators, maintenance, contractors) • What are the chemicals used?
Part of the Gas Plant Feed 3. Light Naphtha Stabilizer Gas 2. Gas from Crude & Syn Tower 6. Sovaformer Liquid 1. Syn Tower Accum
Process • Gas from three streams #2, #3, #6 are combined, compressed, (water removed) into stream #7 • Stream #1 & #7 are feed for the ‘Reboiled Absorber’ (fractionator) which produces streams #8 (gas) which is further separated gas streams #10 & #12 (for fuel gas), and liquid #14 which is further fractionated in the Stabilizer to stream #16 (gas) (Overheads) for the Alkylation unit feed. • The bottoms from the Stabilizer #15 is Stabilized Gasoline which will add to gasoline blend stocks
Feed Streams to the Gas Plant Part of Gas Plant P&I shows the feed to the gas plant comprises the following identified by numbers #3. Light Naphtha Stabilizer Gas from the reformers #2. Gas from Crude & Synthetic Tower (Vac tower) #6. Sovaformer Liquid #1. Syn Tower Accumulator This combination of hydrocarbon streams (gases & liquid) need to be separated
What do we know of the feed? • SyntheticTower Accumulator Liquid #1 • 42% of feed to Gas Plant , Hydrogen Sulphide 0.05% Mostly iC5 9%, nC5 5% & C6+ 80% • ST Accumulator Vapour #2 • 45% of feed to Gas Plant , Hydrogen Sulphide 2.8% Wide range Hydrogen to C6+
What do we know? • CT Accumulator Vapour #2 • 5% of feed to Gas Plant , C3 (28%), C4s (33%), C5s (20%), C6+ (10%) • Light Naphtha Stabilizer Gas #3 • 5% of feed to Gas Plant , similar to CT Accumulator Vapour • Sovaformer Liquid #6 • <2% of feed to Gas Plant , C3 (16.0%), C4s (70%)
What are potential problems? • Hydrogen Sulphide 2.8% ST Accumulator Vapour stream • Probably No Benzene • Wide range of hydrocarbons from hydrogen to C6+
What do we know of the products? • Fuel Gas • Dry Gas #10, Fuel Gas #12 • Stabilized Gasoline • Gasoline blend stock #15 • Feed for Alkylation Unit • #16 comprising C3, and importantly Isobutane , Propylene
Reboiled Absorber Separates the lighter gases into fuel gas and heavier hydrocarbons which provide feed for the next unit
Stabiliser Separates hydrocarbons which provide feed for Alkylation Unit and stabilised gasoline for the gasoline pool
End of Section 17 Design & Review