Ch 26 Process Auxiliries

Flare system

A connected system of individual lines, pressure control valves, and relief/safety valves used in overpressure and purging situations to eliminate volatile process gases by combustion before they are released into the atmosphere

Flare header

A pipe system that connects several area/unit vents to the flare stack

Knockout drum

A vessel located between the flare header and the flare stack that separates liquid substances from vapors being sent into the flare stack

Flare stack

The riser section or body of the flare system that supports the steam ring and pilot burner

Pilot burner

A continuous ignition source at the flare tip that ignites gases as they are released from the system

Steam ring

A component at the tip of the flare that distributes steam to create draft, reduce smoke, and protect the flare tip from heat

Continuous purge gas

Gas constantly flowing through the flare stack to prevent oxygen from migrating in and causing flashback

Hot-service flare

A flare system that collects fluids above 32°F (0°C)

Cold-service flare

A flare system that collects fluids below 32°F (0°C)

Refrigerant

A fluid with a low boiling point that is circulated throughout a refrigeration system to transfer heat

Evaporator

A heat exchanger in a refrigeration system where the refrigerant absorbs heat from the process stream, causing the refrigerant to evaporate (cold side)

Compressor

A device that increases the pressure of the refrigerant in the gas phase

Condenser

A device that cools the gas phase refrigerant from the compressor so it condenses back into a liquid (hot side)

Receiver

A tank that stores liquid phase refrigerant after it leaves the condenser

Expansion valve

A valve that reduces the pressure of liquid refrigerant, causing it to vaporize and produce a cooling effect

Mechanical refrigeration system

A closed loop refrigeration system that uses a refrigerant cycled through an evaporator, compressor, condenser, receiver, and expansion valve

Absorption refrigeration system

A refrigeration system that cycles water and a heat absorbent material (typically lithium bromide) through a closed loop with an evaporator, condenser, absorber, and generator

Lubricant

A substance used to reduce friction between two contact surfaces; common types are oil and grease

Lubrication system

A system that supplies oil or grease to rotating equipment parts such as bearings, gearboxes, sleeve bearings, and seals

Lube oil reservoir tank

A vessel that contains lubricating oil for a lubrication system

Pressure differential across filter

The difference in pressure before and after a filter; a rising differential indicates the filter is getting clogged and restricting flow

Grease gun

A handheld device used to manually apply grease to equipment components such as bearings

Automatic grease lubricator

A device (also called a grease cup) that slowly forces grease from a reservoir into a part to keep it lubricated

Hot oil system

A system that uses an organic or synthetic oil as a heat transfer fluid; used to heat jacketed reactors, tanks, heat exchangers, and pipeline tracing to prevent freezing of heavy oil products

Hot oil system components

Storage tank, oil heating system (heater/furnace), oil circulation system (piping), and oil pump

Amine system

A system used to remove CO2 or other acid gases from a gas stream using a countercurrent flow of amine solution in a contactor vessel

Contactor (absorber)

The vessel in an amine system where sour gas flows upward through trays while amine flows downward, absorbing acid gases

Rich amine

Amine that is saturated with acid gases (CO2 or H2S) after passing through the contactor

Lean amine

Amine that has had acid gases stripped out in the regenerator and is ready to be recycled back to the contactor

Regenerator (stripper)

The vessel in an amine system where rich amine is heated to boil out entrained acid gases, producing lean amine

Sweet gas

Process gas that has had acid gases removed by the amine system; the clean output from the contactor

Fluidized bed system

A system that uses a motive gas flowing up through small holes in a bed floor to make solid particulate substances move and behave like a fluid

Nitrogen header system

A system used to purge oxygen before introducing combustible gases (startup) or to purge combustibles before opening equipment to atmosphere (shutdown)

Why nitrogen is used for purging

Nitrogen is inert — it does not react with oxygen or combustible gases, making it safe to use as a purge medium

Flare hazard — pilot not lit

Possible exposure to toxic fumes, fire or explosion risk, process upset, potential environmental release

Flare hazard — knockout drum overfills

Burning liquid ejected from flare tip; back pressure on flare header creating dangerous system pressure buildup; potential environmental spill or fire

Refrigeration hazard — refrigerant leak

Exposure to toxic fumes or chemical burns, fire or explosion risk, process upset, environmental release

Refrigeration hazard — cooling water failure to condenser

Refrigerant cannot condense back to liquid, cycle breaks down, equipment damage, process upset

Lubrication hazard — loss of lubrication

Bearing failure, excess heat, equipment seizure, process upset

Hot oil hazard — drain valve left open

Burns and injury to personnel, equipment failure, process upset, environmental spill and fire risk

Flare monitoring tasks

Maintain knockout drum level, check knockout drum pump, check pilot gas regulator flow, verify pilot is lit, check purge gas flow

Refrigeration monitoring tasks

Check cooling water to condenser, check compressor operation, check expansion valve, check system temperature profile

Lubrication monitoring tasks

Maintain proper oil levels, check bearing lubrication, check grease fittings, check inlet/outlet temperatures, check lubrication flow, check pressure differential across filter, check pump operation

Hot oil monitoring tasks

Check pump operation, check tank temperature, check oil circulating temperature, check oil tank level, check circulating valve alignment

Refrigeration cycle order

Evaporator → Compressor → Condenser → Receiver → Expansion valve → back to Evaporator

1

flare tip The final exit point where gas is burned; designed for stable combustion.

5

knockout drum or sump system Separates any liquids from the gas stream before it enters the stack.

2

pilot A small, continuous flame used to ignite the waste gases.

4

flare stack The vertical pipe that elevates the flame away from ground-level personnel.

3

steam ring Injects steam into the flame to improve turbulence and ensure smokeless burning.