Presentation by: Yogesh Rahate

Introduction to Introduction to Flare SystemFlare System

WHAT IS FLARE EQUIPMENT?

A device or system used to safely dispose of relief gases in an environmentally compliant manner through the use of combustion.

BASIS OF FLARE DESIGN

Reduce ground level concentrations of hazardous materials.

Provide the safe disposal of flammable materials.

Reduce volatile organic compound (VOC) and hydrocarbon emissions.

FLARE TYPES

VERTICAL: Vertical flares generally oriented to fire upward. There are several types of Support methods for the

vertical flares. They include:

Self supported Guyed supported Derrick supported Demountable derrick

TYPES OF VERTICAL FLARES

SELF SUPPORTED

DERRICK SUPPORTED

GUY WIRE ROPE

TYPES OF VERTICAL FLARES

Demountable single section riser

Demountable multiple section riser

TYPICAL ELEVATED FLARE

FLARE TYPES

HORIZONTAL: The flared liquids and gases are piped to a horizontal flare burner

that discharges into a pit or excavation.

TYPES OF ENCLOSED FLARES

Single point flares Multi-burner Staged flares Smokeless & Non smokeless flares Endothermic (Fuel gas assisted) Flares

FLARE TYPES

ENCLOSED FLAME FLARES: Enclosed flares are constructed to conceal the flame from direct view. They can reduce noise and minimize radiation. Multiple stages within the enclosed flares are sometimes used.

ENCLOSED FLAME FLARES

FLARE TYPES

SMOKELESS FLARES : Smokeless flares eliminate any noticeable smoke over a specified range of flows.

Smokeless flares can be provided with a steam-assist or air-assist system to improve combustion. Air-assist system utilizes fans to provide mixing energy at the tip.

FLARE TYPES

NON-SMOKELESS FLARES: Non-smokeless flares utilize no outside methods ( air, steam, etc.) to improve combustion. This sometimes results in the presence of smoke at certain operating conditions.

Non-smokeless flares are used for hydrocarbon or vapor streams that do not cause smoking (i.e. methane, hydrogen, carbon monoxide, clean coke oven gas, ammonia, hydrogen sulfide) or when smoke is not concern.

FLARE TYPES

ENDOTHERMIC ( FUEL GAS ASSISTED) FLARES: Endothermic (fuel gas assisted) flares require supplemental heat when flaring low heating value waste streams (such as tail gas)

MAJOR COMPONENTS Flare stacks Flare burners Pilot (s) Pilot igniters Pilot flame detectors (UV Sensor) Support structure Flame / detonation arrestor Control Cabinet Interconnecting piping / wiring / cabling between stack & control cabinet All field instruments including transmitters, gauges, valves. PLC including flare logic (i.e. All PLC’s with operator stations / local panels with

controllers, indicators, relays, etc. for proper operation & interlocking of the system + interface signals from / to purchasers control + safeguarding systems )

Silencers. Combustion air blower Louvers Rain shields Water seal drum Flame front generator panel Knock out drum

FLARE BURNER

• This mechanical device mixes fuel and air at required velocities to establish and maintain proper ignition and stable combustion without exceeding the system allowable pressure drop.

• With or without assistance (Steam / Air / Fuel)

• Design based on relief gas characteristics & exit velocities.

• Attachments like Wind Shields, Refractory, etc.

PILOTS & PILOT IGNITER

• The primary purpose of pilot is to ignite the relief gas.

• Always on

• Mostly premixed (Fuel + Air)

• 4 types of pilot ignition

• FFG Conventional

• FFG Self Inspiriting

• Spark probe igniter

• Direct spark

PILOTS & PILOT IGNITER

SEALS

• The main function is to restrict the atmospheric air from entering the flare riser.

• Usually an inactive purge gas is used. However to reduce the consumption of purge gas, seal is used.

• 2 types - Molecular seal and Dynamic / Velocity Seal

LIQUID SEALS & KNOCK-OUT DRUM

• The liquid seal works here as a flame arrestor and also prevents air from entering pipe header.

• The knock-out drum’s purpose is to eliminate all liquid droplets from riser gas.

LIQUID SEALS & KNOCK-OUT DRUM

INSTRUMENTATION

Flame detection- Thermocouple- Flame ionization- Optical- Acoustics

Control panel & instruments for pilot fuel line. Flow (Mainly for staging) Pressure (Mainly for staging)

SELECTION CONSIDERATIONS

Safety Requirements and Environmental Regulations. Initial capital cost, operating & maintenance expenses. Gas flow rates & characteristics (composition, pressure

& temperature) Neighborhood Relationships, availability & cost of

utilities, space availability. Function of the overall plant design & location.

COMPARISION OF ENCLOSED FLARES OVER ELEVATED FLRES

Very low noise Very low & controlled emissions Very simple, accessible controls & convenient service

at grade level No thermal radiation Stable burning of waste gas is assured even in a strong

wind.

THERMAL RADIATION

The acceptability of heat radiation levels is dependant on 1) the effect on humans,2) the effect on equipments.

The calculation method to determine the the heat radiation levels of burning flares is given in API RP 521.

Taking into account topographical & meteorological conditions, the height of the flare stack shall be selected to meet the following conditions:

1) The sterile area radius should be 60m.

2) At the boundary of the sterile area, the heat radiation level shall be 6.3 kW/m2

maximum (excluding the effect of solar radiation).

3) At the property limit the heat radiation level shall be 3.15 kW/m2 maximum (excluding the effect of solar radiation.)

CODES USED FOR FLARES

1) API 537

2) API RP 521

GROUND FLARE PACKAGE BY C-NOX

PROCESS DATA

Process Gas – (Vent Gas) Capacity - 45 Sm3/h (Min) 4510 Sm3/h (Max.) Design pressure – 5 mbarg (Min) -16 mbag (Max.)

Pilot Gas – (Natural Gas) Pilot Gas consumption rate - 10Sm3/h Design Pressure – 10barg

PROCESS DATA

For non flame affected parts only Design Temperature – 90oC (Max.) - 20oC (Min.)

For flame affected parts only Design Temperature – 1300oC (Max.) - 500oC (Min.)

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ELEVATED FLARE PACKAGE BY AIROIL

STACK DRAWING

FLARE TIP DRAWING

FFG PANEL DRAWING

PROCESS DATA

Process Gas – Hydrocarbon Capacity - 50 Kg/hr (Min) 40000 Kg/h (Max.) Design pressure – 3.5 Kg/cm2 g Design Temperature – 100oC Pilot Gas – (LPG Gas) Pilot Gas consumption rate - 1.84 Kg/hr Steam consumption rate - 8000 Kg/hr

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