Reciprocatingcompressor have the pistons which slide up and down and compress the gas centrifugal compressor has a rotary impeller which compressed the working fluid through its rotational motion Screw compressors have 1 pair of screws move rotary and compressed the flow of fluid. There are other smaller parts that can be named but these are the main players.
The scroll compressor also has an oil pick up tube which differs from a reciprocating compressor. It has an oil pump, reed valve plate, uploaders, pistons, bearings, etc.
Cancompressorsurge occur in reciprocating piston compressor ? The compressor surge is a type of instability that usually happens in axial or centrifugal compressors.
A reciprocating compressor is one in which a piston or diaphragm moves in a reciprocating motion. A reciprocating compressor is one in which a piston or diaphragm moves in a reciprocating motion.
Surge is defined as the operating point at which the compressor peak head capability and minimum flow limit are reached. The compressor loses the ability to maintain the peak head when surge occurs and the entire system becomes unstable.
The surge cycle may result in a small or large flow reversal period depending on the discharge gas volume and the pressure ratio. Chronic surge is characterized by intermittent periods of small flow reversal that may not cause severe damage to the machine.
Any surge event can cause severe damage to the thrust bearings, seals, and the impeller. Surge is not the rough operation, vibration (see vibronurse.com for more details), pulsation, or noise that develops at low flow conditions which is referred to as stall or incipient surge.
Reciprocatingcompressor have the pistons which slide up and down and compress the gas centrifugal compressor has a rotary impeller which compressed the working fluid through its rotational motion Screw compressors have 1 pair of screws move rotary and compressed the flow of fluid. The scroll compressor also has an oil pick up tube which differs from a reciprocating compressor.
Surge can be defined as the capacity below 55 to 70%, which the centrifugal compressor performance becomes unstable. When surging occurs, the high-pressure gas at the discharge of the machine flows back through the compressor in a complete reversal of the normal direction of flow causing the collapse of pressure producing ability will repeat and cycle through the same sequence.
Surging in pumps can be controlled by NASH (net positive suction head). A Compressor is used for gas or air suction as gases are compressible.
Without a doubt, Surge might create a dead-end for natural gas compression. On the other, surge represents a point at which the compressor will no longer be able to supply energy to the gas to push through the compressor and further through the check valve to the discharge piping section.
Surge action takes place within a fraction of seconds (150 Milliseconds). When there is a sudden fluctuation in the Ammeter, it could be assumed that surging had taken place.
It usually happens between 50-80 % of the design flow which is also depending on the case and impellers of the compressor. There is a sudden drop in the gas flow as well as in discharge and suction pressure.
If there is any blockage in intercooler piping, the flow of gas will drop. Surge can take place in both the compressors, auxiliary and centrifugal.
At this point, the pressure in the discharge piping section will be much higher than the pressure in the compressor section, which eventually leads to the surging of the gas flow in a reverse direction through the compressor. Due to the unstable behavior of surge, it should be avoided to prevent the damage to auxiliary equipment.
The anti- surge control valve is added at the suction to the compressor and at the receiver (discharge) entry point. In other words, the returned gas from the receiver gets recycled and reused in the suction chamber and the process continues without any interruption.
11/08/2010 A: Balasubramanian Dyer, Been COOL Limited, firstname.lastname@example.org Anti Surge is a process witnessed only in Centrifugal compressors as Kinetic Energy of the fluid is converted into the Pressure energy. Surging is not witnessed in Reciprocating Compressors, as they are positive displacement Equipments where the pressure increased is by volume reduction, hence providing anti surge in reciprocating is not envisaged and not proper. Anti Surge is witnessed when the flow to the Centrifugal Compressor is reduced or the density of the fluid entering the Compressor is altered to greater extent, pressure is reduced to a lower extent. The surge valve opens and increases the flow to the suction there by bringing back the condition to normal operation there by saving the equipment from damage.
This failure is known to have been the cause of a number of plane crashes, including the famous emergency ditching of a US Airways A320 jet in the Hudson River near Newark, New Jersey in 2009. Early jet engines experienced this phenomenon more often due to primitive fuel delivery systems.
As conditions that cause compressor surge build and approach a critical point, modern jet engines have automatic systems in place to meter fuel delivery to help prevent surges. For auto enthusiasts, the phenomenon of compressor surge as experienced by a turbocharger results in a “chattering” sound from the engine.
This is actually a series of banging noises at a rapid frequency as the exhaust gases in the turbocharger oscillate, causing the mechanism to stop and start or to speed up and slow down, resulting in a very uneven delivery of boost, or power. The phenomenon can occur in any closed system employing a compressor with a flow in a specific direction under normal operation.
The Most Beautiful Women Forecasting the Weather Amazing Optical Illusions That Will Play Tricks on Your Mind 40 Wedding Picture Fails You Don't Want to Miss 17 Interesting Maps That Will Change Your Worldview Compressor surge is a cyclic event and this results in high strain in compressor bearings, seals, and the impeller.
As long as this surge will prevail, a large dynamic force will act on the compressor impeller and blade. The effects of the compressor surge are also contagious and due to excessive shaft vibrations, the gearbox connected between the compressor and the driver are also not spared at the bearings and gear teeth.
Although the anti- surge valve (ASV) is the chief protector, in brownfield projects, often the ASV becomes inadequate to deal with a compressor surge due to the addition of new compressors in parallel or series (e.g., booster compressors), change of plant piping or change of vapor composition. When such solutions still fail to stop a compressor surge event from occurring, a hot gas recycles (a.k.a. HPV) is used as a last resort.
Excessive hot gas recycle also shortens the efficacy of the lube oil that is used for lubrication purposes. During an ESD scenario (e.g., power loss), taking a conservative approach for design purposes, the control output signal from the compressor driver after a trip, takes ~300 milliseconds to reach the Distributed Control System (DCS) and another ~300 milliseconds from the DCS to reach the HPV to open.
In simple terms, lower response time increases the chances of responding faster to a compressor surge. However, this needs to be checked with a dynamic simulation study since over-sizing the Hot gas system can cause the compressor to overheat the bearings and seals.
In the event that the above design criteria cannot be met, purchaser and vendor shall mutually agree on acceptable bearing metal temperatures. In today’s world, no piece of machinery can be said to be protected by modern methods without implementing a control system.
Although the good old Proportional-Integral-Derivative (PID) control was enough to avoid a compressor surge by minimizing the compressor recycle flow, it did not aid much in reducing/optimizing the power requirements. With a steady rise in oil consumption since the 1970s, the necessity of energy efficiency, safety, and environmental friendliness became a priority and demanded better control systems.
This led to the rise of specialized control equipment known as ‘ Black Boxes’ that was the alternate to panel mounted instruments. Black boxes though addressed response times, suffered from frequent hardware and software revisions.
Black box technology was proprietary with their own coding languages and often experienced compatibility issues when interfacing between different manufacturers’s/models. This also meant having to sometimes shut down the machinery causing monetary implications and increased downtime if not made part of plant maintenance.
With the limitations of using black box technology being recognized, industry honchos realized the necessity of standardizing and generalizing control systems and their respective programming languages. In earlier systems that depended on the black box principle, a primary PLC is supplemented with an auxiliary PLC that controlled systems like lube oil, seal oil / dry gas seals, startup sequencing, interlocks, etc.
This also required interfacing them properly to allow operators to diagnose and do a root cause analysis in the event of, for example, a compressor trip.