Process Unit Shutdown 2/3

What is a critical path in the planned work event?

• A sequence that is irrelevant to other work

• A sequence that may delay other work if not completed

• A sequence that is not important in the planned work event

• A sequence that is always completed first

What is the purpose of purging with an inert gas after draining hydrocarbons from piping and vessels?

• To remove any remaining hydrocarbons and prevent explosions

• To introduce more hydrocarbons into the vessels

• To increase the pressure inside the vessels

• To cool down the equipment

What should be done before allowing entry into vessels during shutdown?

• Check the temperature of the vessels

• Check the color of the vessels

• Check the pressure of the vessels

• Check vessels daily for LEL

What should be done to prevent pump seal damage during product pump out?

• Increase the speed of the pumps

• Shutdown mechanical seal pumps immediately before liquid levels are depleted

• Allow the pumps to run dry

• Use the pumps continuously

What should be done when shutting down furnace fires to prevent a firebox explosion?

• Leave the firebox open

• Close the master valve and keep the burner lighted

• Open all valves and turn off the burner

• Increase the fuel flow

What should be done before steam purging to prevent equipment damage?

• Introduce more water into the equipment

• Increase the pressure inside the equipment

• Drain all water from water-cooled heat exchanger and open the vent

• Close all vents

What is the main purpose of securing equipment during unit clear up?

• To prevent accidents and equipment damage

• To increase the temperature inside the equipment

• To speed up the shutdown process

• To allow more feed into the equipment

What is the purpose of deinventoring unit vessels and piping during shutdown?

• To introduce more hydrocarbons into the vessels

• To cool down the equipment

• To increase the pressure inside the vessels

• To remove all process materials

What should be done to avoid hazards during shutdown?

• Increase the risk of hazard

• Preparation and training for shutdown and start-up

• Ignore all procedures

• Use poorly trained contract workers

What is the most frequently encountered hazard during shutdown?

• Poor communication

• Mixing of air and hydrocarbons to form explosive mixtures

• Contact with corrosive or toxic liquids and gases

• High pressures