Guidelines For Euipment And Piping Location Part 1 - Online Article

This article should only be used as a guide. It’s intended purpose is to help the piping designer who is responsible for placement of one specific item in a typical refinery, chemical or petrochemical process plant or someone who may need help in developing a total plot plan for a complex unit.

Compressors, Centrifugal

Locate centrifugal compressor as close as possible the suction source. Top suction and discharge lines either should be routed to provide clearance for overhead maintenance requirements, or should be made up with removable spool pieces.

Support piping so as to minimize dead load on compressor nozzles; the load should be within the recommended allowance of the compressor manufacturer.

Centrifugal compressors should have full platforming at operating level. Heavy parts such as upper or inner casing and rotor should be accessible to mobile equipment. Review the equipment arrangement for access and operation.
  Locate lube and seal oil consoles adjacent to and as close as possible to the compressor. Oil return lines from the compressor and driver should have a minimum slope of 1/2 inch per foot to the inlet connection of seal traps, degassing tanks, and oil reservoir. Pipe the reservoir, compressor bearing, and seal oil vents to a safe location at least 6 feet above operator head level.

Compressors, Reciprocating

Locate reciprocating compressors so suction and discharge lines that are subject to vibration (mechanical and acoustical) may be routed at grade and held down at points established by a stress and analog study of the system.
  Accessibility and maintenance for large lifts such as cylinder, motor rotor, and piston removal should be by mobile equipment if the installation is outdoors or by traveling overhead crane if the installation is indoors (or covered).
Horizontal, straight line, reciprocating compressors should have access to cylinder valves. Access should be from grade or platform if required.

Depending on unit size and installation height, horizontal-opposed and gas engine driven reciprocating compressors may require full platforming at the operating level.

Control Valves

Locate control valve stations accessible from grade or on a platform. In general, the (flow, level, pressure, temperature) instruments or indicators showing the process variables should be visible from the control valve.

Cooling Towers

Locate cooling towers downwind of buildings and equipment to keep spray from falling on them. Orient the short side of the tower into the prevailing summer wind for maximum efficiency. This means that the air flow (wind) will travel up the long sides and be drawn in to both sides of the cooling tower equally. When the wind is allowed to blow directly into one long side it tends to blow straight through and results in lower efficiency. Locate cooling towers a minimum of 100 feet (30m) from process units, utility units, fired equipment, and process equipment.

Cradles

Equipment Arrangement (General)

Arrange equipment, structures, and piping to permit maintenance and service by means of mobile equipment. Provide permanent facilities where maintenance by mobile equipment is impractical.
Group offsite equipment, pumps, and exchangers to permit economical pipe routing. Locate this equipment outside of diked storage areas.

Exchanger, Air Cooler (Fin Fans)

Air Coolers are in typically used in the cooling of the overhead vapor from tall vertical vessels or towers such as Crude Fractionators and Stripper Columns. The natural flow tends to follow gravity, where the tower overhead is the high point then down to the Air Cooler, then down to the Accumulator and finally the Overhead Product transfer pumps. With this in mind the Air Coolers are normally located above pipeways. This conserves plot space and allows the pipe rack structure with it’s foundation to do double duty with only minor up grade to the design. If the pipe rack is not used then plot space equal to the size of the Air Cooler is required. In addition a totally separate foundation and stand alone structure is required.

Exchanger, “G” Fin (Double Pipe)

These exchangers can be mounted almost anywhere any they can be mounted (with process engineer approval) in the vertical when required. A G-Fin Exchanger is recognizable by its shape. One segment looks like two long pieces of pipe with a 180 degree return bend at the far end. It is one finned pipe inside of another pipe with two movable supports. This type of exchanger can be joined together very simply to form multiples in series, in parallel or in a combination of series/parallel to meet the requirements of the process. This exchanger is not normally used in a service where there is a large flow rate or where high heat transfer is required. The key feature with this exchanger is the maintenance. The piping is disconnected from the tube side (inner pipe). On the return bend end of this exchanger there is a removable cover. When the cover is removed this allows for the tube (inside pipe) to be pulled out. This exchanger is normally installed with the piping connections toward the pipe rack.

Exchangers, Reboiler (Kettle Reboiler)

Locate kettle reboilers at grade and as close as possible to the vessel they serve. This type of reboiler is identifiable by its unique shape. It has one end much like a normal Shell and Tube exchanger then a very large eccentric, bottom flat transition to what looks like a normal horizontal vessel. You could also call it a “Fat” exchanger. The flow characteristics on the process side of a kettle reboiler are the reason for the requirement for the close relationship to the related vessel.
Reboilers normally have a removable tube bundle and should have maintenance clearance equal to the bundle length plus 5 feet (1.5m) measured from the tube sheet.

Exchangers, Shell and Tube

Shell and tube exchangers should be grouped together wherever possible. Stacked shell and tube exchangers should be limited to four shells high in similar service; however, the top exchanger should not exceed a centerline elevation of 18 feet (5.5m) above high point of finished surface, unless mounted in a structure. Keep channel end and shell covers clear of obstructions such as piping and structural members to allow unbolting of exchanger flanges, and removal of heads and tube bundles.

Exchangers with removable tube bundles should have maintenance clearance equal to the bundle length plus 5 feet (1.5m) measured from the tube sheet to allow for the tube bundle and the tube puller.

Maintenance space between flanges of exchangers or other equipment arranged in pairs should be 1'- 6? (0.5m) (min.). Exchanger maintenance space from a structural member or pipe should not be less than 1'- 0? (300mm) (min.).

Furnaces (Fired Equipment)

Locate fired equipment, if practical, so that flammable gases from hydrocarbon and other processing areas cannot be blown into the open flames by prevailing winds.

Horizontal clearance from hydrocarbon equipment (shell to shell) 50'- 0? (15m) Exception: Reactors or equipment in alloy systems should be located for economical piping arrangement.

Provide sufficient access and clearance at fired equipment for removal of tubes, soot blowers, air preheater baskets, burners, fans, and other related serviceable equipment.

Clearance from edge of roads to shell 10'- 0?(3m)

Pressure relief doors and tube access doors should be free from obstructions. Orient pressure relief doors so as not to blow into adjacent equipment.

The elevation of the bottom of the heater above the high point of the finished surface should allow free passage for operation and maintenance.

This article should only be used as a guide. It’s intended purpose is to help the piping designer who is responsible for placement of one specific item in a typical refinery, chemical or petrochemical process plant or someone who may need help in developing a total plot plan for a complex unit.

Compressors, Centrifugal

Locate centrifugal compressor as close as possible the suction source. Top suction and discharge lines either should be routed to provide clearance for overhead maintenance requirements, or should be made up with removable spool pieces.

Support piping so as to minimize dead load on compressor nozzles; the load should be within the recommended allowance of the compressor manufacturer.

Centrifugal compressors should have full platforming at operating level. Heavy parts such as upper or inner casing and rotor should be accessible to mobile equipment. Review the equipment arrangement for access and operation.
  Locate lube and seal oil consoles adjacent to and as close as possible to the compressor. Oil return lines from the compressor and driver should have a minimum slope of 1/2 inch per foot to the inlet connection of seal traps, degassing tanks, and oil reservoir. Pipe the reservoir, compressor bearing, and seal oil vents to a safe location at least 6 feet above operator head level.

Compressors, Reciprocating

Locate reciprocating compressors so suction and discharge lines that are subject to vibration (mechanical and acoustical) may be routed at grade and held down at points established by a stress and analog study of the system.
  Accessibility and maintenance for large lifts such as cylinder, motor rotor, and piston removal should be by mobile equipment if the installation is outdoors or by traveling overhead crane if the installation is indoors (or covered).
Horizontal, straight line, reciprocating compressors should have access to cylinder valves. Access should be from grade or platform if required.

Depending on unit size and installation height, horizontal-opposed and gas engine driven reciprocating compressors may require full platforming at the operating level.

Control Valves

Locate control valve stations accessible from grade or on a platform. In general, the (flow, level, pressure, temperature) instruments or indicators showing the process variables should be visible from the control valve.

Cooling Towers

Locate cooling towers downwind of buildings and equipment to keep spray from falling on them. Orient the short side of the tower into the prevailing summer wind for maximum efficiency. This means that the air flow (wind) will travel up the long sides and be drawn in to both sides of the cooling tower equally. When the wind is allowed to blow directly into one long side it tends to blow straight through and results in lower efficiency. Locate cooling towers a minimum of 100 feet (30m) from process units, utility units, fired equipment, and process equipment.

Cradles

Equipment Arrangement (General)

Arrange equipment, structures, and piping to permit maintenance and service by means of mobile equipment. Provide permanent facilities where maintenance by mobile equipment is impractical.
Group offsite equipment, pumps, and exchangers to permit economical pipe routing. Locate this equipment outside of diked storage areas.

Exchanger, Air Cooler (Fin Fans)

Air Coolers are in typically used in the cooling of the overhead vapor from tall vertical vessels or towers such as Crude Fractionators and Stripper Columns. The natural flow tends to follow gravity, where the tower overhead is the high point then down to the Air Cooler, then down to the Accumulator and finally the Overhead Product transfer pumps. With this in mind the Air Coolers are normally located above pipeways. This conserves plot space and allows the pipe rack structure with it’s foundation to do double duty with only minor up grade to the design. If the pipe rack is not used then plot space equal to the size of the Air Cooler is required. In addition a totally separate foundation and stand alone structure is required.

Exchanger, “G” Fin (Double Pipe)

These exchangers can be mounted almost anywhere any they can be mounted (with process engineer approval) in the vertical when required. A G-Fin Exchanger is recognizable by its shape. One segment looks like two long pieces of pipe with a 180 degree return bend at the far end. It is one finned pipe inside of another pipe with two movable supports. This type of exchanger can be joined together very simply to form multiples in series, in parallel or in a combination of series/parallel to meet the requirements of the process. This exchanger is not normally used in a service where there is a large flow rate or where high heat transfer is required. The key feature with this exchanger is the maintenance. The piping is disconnected from the tube side (inner pipe). On the return bend end of this exchanger there is a removable cover. When the cover is removed this allows for the tube (inside pipe) to be pulled out. This exchanger is normally installed with the piping connections toward the pipe rack.

Exchangers, Reboiler (Kettle Reboiler)

Locate kettle reboilers at grade and as close as possible to the vessel they serve. This type of reboiler is identifiable by its unique shape. It has one end much like a normal Shell and Tube exchanger then a very large eccentric, bottom flat transition to what looks like a normal horizontal vessel. You could also call it a “Fat” exchanger. The flow characteristics on the process side of a kettle reboiler are the reason for the requirement for the close relationship to the related vessel.
Reboilers normally have a removable tube bundle and should have maintenance clearance equal to the bundle length plus 5 feet (1.5m) measured from the tube sheet.

Exchangers, Shell and Tube

Shell and tube exchangers should be grouped together wherever possible. Stacked shell and tube exchangers should be limited to four shells high in similar service; however, the top exchanger should not exceed a centerline elevation of 18 feet (5.5m) above high point of finished surface, unless mounted in a structure. Keep channel end and shell covers clear of obstructions such as piping and structural members to allow unbolting of exchanger flanges, and removal of heads and tube bundles.

Exchangers with removable tube bundles should have maintenance clearance equal to the bundle length plus 5 feet (1.5m) measured from the tube sheet to allow for the tube bundle and the tube puller.

Maintenance space between flanges of exchangers or other equipment arranged in pairs should be 1'- 6? (0.5m) (min.). Exchanger maintenance space from a structural member or pipe should not be less than 1'- 0? (300mm) (min.).

Furnaces (Fired Equipment)

Locate fired equipment, if practical, so that flammable gases from hydrocarbon and other processing areas cannot be blown into the open flames by prevailing winds.

Horizontal clearance from hydrocarbon equipment (shell to shell) 50'- 0? (15m) Exception: Reactors or equipment in alloy systems should be located for economical piping arrangement.

Provide sufficient access and clearance at fired equipment for removal of tubes, soot blowers, air preheater baskets, burners, fans, and other related serviceable equipment.

Clearance from edge of roads to shell 10'- 0?(3m)

Pressure relief doors and tube access doors should be free from obstructions. Orient pressure relief doors so as not to blow into adjacent equipment.

The elevation of the bottom of the heater above the high point of the finished surface should allow free passage for operation and maintenance.

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