Cairo UniversityFaculty of Engineering

Petrochemicals Engineering

Plant Layout

May 2010

Plant Layout• It is the challenge to make the best use of the

site based on process needs, capital costs, life cycle costs, safety, health, security and environmental considerations.

• Steps for new projects or modification to existing facilities:

1. Consider the site environment and its surroundings.2. Arrange the major blocks: process, utilities, off-sites

and buildings.3. Perform the detailed layout and spacing within the

specific plants and units.

Topography

• Detailed topographical maps will be required (streams, slopes, buildings, elevation changes…).

• Locate open flames (units with heaters, direct fired utility equipment) at higher elevation than bulk quantities of flammables (storage tanks).

• Storage tanks at elevations higher than process area (reduces the protection measures such as: drainage systems, dikes,…)

• Flare is a unique piece (flare plume modeling)

Weather

• In many locations there is not a prevailing wind direction

• The combination of all other wind parameters (direction, speed, time of changes..) are combined into a wind rose.

Block Layout Methodology

• Grouping large blocks of like characteristics (process area, tankage, utilities, office, administration buildings)

• Determine the details of intra-unit spacing within each block

Atmospheric

Tankage

300 x 600 ft.

Low Hazard

Process Areas

600 x 500 ft.

Parking

Maintenance

Warehouse

200 x 600 ft.

Utilities

200 x 300 ft.

Flare

200 x 300 ft.Offices

200 x 200 ft.

200 ft.

NM

200 ft.

100 ft.

Spacing around flare based on radiant heat calculations

Spacing based on local building codes

Property Line Total Land Area = 45 acres

1300 ft.

1500 ft.

NM

100 ft.

100 ft.

Entrance

Utilities• Cooling Tower:– Air is loaded with water vapour fog and clouds icing

conditions and reduce visibility inside and outside the sitelocate cooling tower downwind from roadways, pipe

ways, process equipment.• Flare:– Locate flares upwind from process units.– Elevated flares should have an exclusion zone (152m).– Consider the risk of windblown embers from the flare tip.

Do not locate flares near flammable and combustible containing equipments.

Process Layout

• Process units are grouped together and separated from low hazard areas to minimize fire and explosion exposure.

• Ex.: reactors, vessels, heat exchangers, and rotating equipment.

• The unit battery limits: outer boundary limits that contains the process equipments.

• Typically process units are located outside except: toxic release, odor control, quality control….

Process layout (cont.)

• Emergency access:– To all areas from at least two directions without

requiring crossing of a process unit.– Provide access way 6 m wide every 61 m at least.

• Maintenance access:– should allow the use of mobile equipment. – Consider over head clearance under pipeways and

supports– Consider adequate crane access to minimize the

amount of lifts.

Process layout (cont.)

• Process unit spacing– Large units (high cost) should be separated to minimize potential

financial loss.– Typical separation distances between elements are listed in

tables.– These distances are based on historical and previous

experiences.– Separate by 30 m from equipment handling flammables if shut

down will not affect other equipments.– Separate by 15 m if equipments will shut down at the same time.– Separate the process-unit battery limit by 15 m from a roadway

with unrestricted access.

Storage Tanks

• Locate tanks downwind of potential ignition sources.

• Separate process units from atmospheric storage tanks and LPG and LFG storage tanks to minimize the risk of release, ignition, tank damage in case of fire or explosion.

• Separation distances between tanks depends on tank size, type, insulation, contents.. (check intratank spacing tables)

Atmospheric

Tankage

300 x 600 ft.

Low Hazard

Process Areas

600 x 500 ft.

Parking

Maintenance

Warehouse

200 x 600 ft.

Utilities

200 x 300 ft.

Flare

200 x 300 ft.Offices

200 x 200 ft.

200 ft.

NM

200 ft.

100 ft.

Spacing around flare based on radiant heat calculations

Spacing based on local building codes

Property Line Total Land Area = 45 acres

1300 ft.

1500 ft.

NM

100 ft.

100 ft.

Another example of a typical master plot plan