Typical P&ID arrangement for Centrifugal Compressor Systems | Enggcyc...http://www.enggcyclopedia.com/2012/02/typical-pid-arrangement-centrif... Enggcyclopedia > Blog > Process Design > Process Deliverables > P&ID Typicals and Symbols > Typical P&ID arrangement for Centrifugal Compressor Systems Typical P&ID arrangement for Centrifugal Compressor Systems Figure 1 – Typical P&ID for a centrifugal compressor system 1 of 4 1. Proper centrifugal compressor symbol should be selected first, as shown in figure-1. Normally, a centrifugal compressor is accompanied by a Knock Out Drum (KOD) at the compressor suction and an aftercooler at the compressor discharge, as per a typical compressor PFD. Symbols for these equipments should also be placed on the P&ID before proceeding ahead. All the equipment symbols should be selected from the legend sheets of a particular project. 2. All the nozzles on the compressor, suction drums and aftercooler should then be correctly represented with size and flanges. This includes inlet and outlet nozzles and equipment drains / vents as shown in the typical P&ID in figure-1. 3. Centrifugal compressor suction KOD is intended for removing the entrained liquids before sending gas to the compressor. Demister, mesh pad etc. are used in the knock out drum to efficiently remove the liquid droplets. 4. Compressor aftercoolers are generally air coolers and the related fan, motor etc. should be clearly indicated on the P&ID. If cooling water is used, proper symbol for a heat exchanger should be used. 5. Inlet, outlet lines for each equipment, anti-surge line, drain/vent lines, line to the relief valve etc. are the next to be drawn up. Line number, material class, size etc. is to be correctly assigned to each of the lines. 6. Isolation valves, spectacle blinds, spacers etc. to be used for maintenance should be drawn up next on various lines between the equipments. Requirement for isolation valves, spectacle blind, spaces etc. depend on the project standards, which should be followed while indicating these on the P&ID. Sometimes, to minimize the number of isolation valves between the equipment, they can be placed only at the suction KOD inlet which is inlet of the centrifugal compressor system and discharge of the aftercooler which turns out to be the outlet of the centrifugal compressor system. Spectacle blinds or spacers can be used for isolation between individual equipments for quick 8/23/2014 3:45 PM a nitrogen connection can be provided right after the first isolation valve on the suction KOD inlet line. downstream to the check valve.Typical P&ID arrangement for Centrifugal Compressor Systems | Enggcyc. 9.enggcyclopedia. Performance controller will typically adjust the motor/turbine speed. the anti-surge valves open up to lower the pressure differential and circulate higher gas flow. Pressure transmitters should be provided on compressor suction and discharge line. Pressure gauges should be provided on suction and discharge of the compressor. Level gauges need to be located on the compressor suction knock out drum and temperature gauges on inlet. 14. outlet lines for the aftercooler. 8. 17. in order to achieve optimum performance. Aftercooler discharge and liquid outlet of suction knock out drum correspond to the outlet lines of the compressor system. Search Search for: Search Search Member Login Username: 2 of 4 8/23/2014 3:45 PM . Level transmitters provided on the suction knock out drum are responsible for liquid level control in the drum. http://www.. Signals from these transmitters are sent to an ‘Anti-Surge Controller’. Drains and vents to be provided on the suction / discharge lines. A check valve should be normally provided on the compressor discharge to avoid reverse flow when the pump is not in operation.. An anti-surge line from the aftercooler discharge to the suction KOD inlet should be provided for anti-surge control. The inlet line of the suction KOD corresponds to inlet of the compressor system. to protect the equipments downstream of compressor. Temperature transmitter can be provided on aftercooler for temperature control by sending a signal to adjust the fan speed of the aircooler. Based on the gas flow and differential pressure head developed by the compressor. 12.. suction Knock Out Drum. Emergency Shutdown (ESD) valves can be provided on inlet / outlet lines of the compressors system to isolate whole system in case of a shutdown. compressor casing. No related Pages. Alarms are usually provided for high and high high liquid level conditions. This is simply a guideline and project standards need to be followed when indicating the isolation requirements. for maintenance.. high differential head). Pressure relief valves can be provided on the compressor discharge line. 16.com/2012/02/typical-pid-arrangement-centrif. 7. for completely draining/venting compressor and associated piping. the anti-surge controller operates the anti-surge valves to prevent compressor surge condition. 11. Sometimes. air cooler body etc. All the guidelines given here are very general and may be modified as per specific requirements of any particular project. When the compressor approaches surge condition (low flow. 13. a performance controller can be included in the centrifugal compressor system to control the rotating speed (RPM) of the compressor based on inlet pressure. A flow transmitter should be provided on compressor suction line. For purging the compressor system. Shutdown valves can be located on these lines as shown in figure-1. 15. flow etc. 18. Your Reaction? 147 96 20 38 Inspiring Delighted Whatever Ditch it No related Pages. maintenance. 10. .. Password: forgot password? Remember Me Log Me In Sign up now Sign up for free if you are not a member already. 3 of 4 Home Piping Miscellaneous Process Design Solved Examples Newsletter Calculators Unit Conversion Contact Us 8/23/2014 3:45 PM .Typical P&ID arrangement for Centrifugal Compressor Systems | Enggcyc. http://www.com/2012/02/typical-pid-arrangement-centrif..enggcyclopedia.. enggcyclopedia. 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