This article is about technical requirements of Layout and Spacing of Towers and Vessels in petrochemical plants.
Layout and Spacing of Towers and Vessels in Plants
The layout and spacing of towers and vessels are critical aspects of plant design and must be carefully considered to ensure safe and efficient operation. Proper tower and vessel layout can impact process flow, maintenance access, and overall plant efficiency.
The layout of towers and vessels should consider the inter-relationships between equipment and the plant’s process flow. This includes consideration of the type and size of equipment required to meet process requirements, as well as the space required for maintenance access and other activities.
Towers and Vessels Spacing in Plants
- Towers and vessels are normally arranged to conform with the main flow sequence, provide an economical piping design, and facilitate plant operation. Locate tall towers with their manways and platforms facing an open area or roadway to facilitate construction and maintenance.
- Towers and vessels should usually be placed in a row with their shells lined up to provide an orderly arrangement of platforming and structures. Avoid parallel rows of towers along one side of pipe racks because this creates interference with maintenance access. Consideration should be given to interconnecting platforms on adjacent towers. Horizontal vessels shall normally be lined up with their heads on a common locating line nearest the piperack.
- Spacing of vertical vessels requires complete accessibility around the outside base of the vessel to provide adequate room for painting, applying insulation, and other activities. Control valve stations, steam traps. may be located at base of vertical vessels, if maintenance access is provided to the piping and to skirt openings.
- Vessel drawings must be reviewed to establish the platforming requirements for removal of internals. Davits may be required on towers to permit the lowering of internals, relief valves, catalyst, and any heavy items that must be removed from the tower during a maintenance operation. A clear drop area, open to an accessway at grade, shall be provided.
- Consideration should be given for relief valve maintenance.
- Packed vessels shall have platforms large enough to handle bags or drums of the packing material.
- Reactors and vessels containing catalyst should have access to facilities for loading and dumping the catalyst.
- Day tanks are not usually located in the process area. However, if it is necessary to put a tank in the process area, dikes or curbs are required around any tank that contains hydrocarbons or chemicals, as specified in NFPA 30.
- Storage tanks within process unit battery limits should be limited to a maximum size of 80 meter capacity when they contain flammable liquid or a combustible liquid heated above its flash point. Storage tanks should be spaced so that at least 9 m separation is provided between enclosure dikes and process unit equipment. Atmospheric storage tanks containing combustible liquids below their flash point should be considered as process vessels in regards to spacing with the spacing being measured to the dike. Process equipment and pumps should not be located in diked areas.
- Diked enclosures meeting provisions of NFPA 30 shall be provided for all storage tanks spaced in process units. Diked areas will be sized for the largest tank in the diked area and shall be provided with fire sealed drains piped to the oily water sewer or chemical drain system. Drains shall be equipped with a shutoff valve, located outside the diked area. The shutoff valve should be the indicating type that readily shows valve position.
- Towers and vessels should be spaced at least 3 m from unit pipeways. Reduced spacing is permitted when adequate access for fire fighting and maintenance can be maintained. Towers and vessels should be located at least 15 m from fired heaters or fired reboilers. Equipment integrated with major towers such as unfired reboilers, overhead exchangers, and feed effluent exchangers may be located closer to the fractionating column that they are associated with than is indicated in Tables 1A and 2A. However, access for fire fighting and maintenance must be maintained. Vessels containing flammable or combustible liquids should not be located beneath pipeways or air coolers.
FAQs
What need to be consider during vessel and tower layout?
The spacing of towers and vessels must also consider the routing of piping and the location of other plant infrastructure, such as electrical equipment and instrumentation. The routing of piping should be designed to minimize pressure drop and ensure that the process is operating efficiently.
What is difference between Towers and Vessels?
Towers and vessels are both types of process equipment used in the chemical and petrochemical industry, but there are some differences between them.u003cbru003eu003cbru003eA tower is a tall, cylindrical vessel used for separating or purifying liquids or gases through a distillation or absorption process. Towers are typically used for large-scale industrial processes and can be several stories tall. They often contain trays or packing materials that allow for the separation of different components based on their boiling points or chemical properties.u003cbru003eu003cbru003eOn the other hand, vessels are typically smaller, more general-purpose containers used for mixing, storing, or reacting chemicals. Vessels can be cylindrical, spherical, or any other shape, depending on their intended use. They are often pressurized to allow for high-temperature reactions or to prevent the escape of hazardous gases or liquids.