reciprocating compressor control philosophy

Moreover, the operator can enable the oil heater by pushing a button in the DCS. He obtained a B.S.M.E. However, there are stories about problems with liquids from condensation of saturated vapor streams entering the suction side of the compressor. 29 September 2020. Centrifugal compressors tend to be preferred when the power is above 2 MW, the mole weight (MW) is greater than 10, and the discharge pressure below 100 MPa. Gas engine drives, which could operate in a 75 to 100% speed range, make use of variable speed method for flow control. 16.9. Due to unbalance matters, minimum load on each stage could be changed to 50%. This advanced compression system utilizes a novel and patented concept of driving a permanent magnet piston inside a hermetically sealed compressor cylinder through electromagnetic windings. Justin Hollingsworth, ... Franzisko Maywald, in Compression Machinery for Oil and Gas, 2019. At compressor normal stop, post lubrication time starts for approximately 2 min, and the cylinder oil pump switches off automatically afterwards. R. Keith Mobley, in Fluid Power Dynamics, 2000. C Control. The installation At a refinery in the US, a Nuovo Pignone reciprocating compressor was put into operation in 2004. Such maintenance is crucial to reciprocating compressors because they rely on the lubrication system to provide a uniform oil film between closely fitting parts (e.g., piston rings and the cylinder wall). This pulsation often generates resonance in the piping system, and pulse impact (i.e., standing waves) can severely damage other machinery connected to the compressed-air system. This causes the compressor to draw in less air, matching compressor capacity with air usage for relatively steady pressure control. PDF | Control Methods for centrifugal compressors, especially in oil and gas service. For safety, all pressurised lines have relief valves. Now the first stage bypass (PCV1) will be able to control the main suction pressure (PT1) with PCV2 in parallel. Note that in compressors, which are only started by bypass method, the starting procedure is performed with bypass valves fully open. Clearance pockets can be arranged for local manual operation, manual/pneumatic operation, or automatic/pneumatic operation. Reciprocating compressors are widely used in the chemical, oil, and gas industries for moving compressible fluids reliably. Multiple frames are sometimes used with a common crankshaft in a compound arrangement to use a common driver. electric motor). 5. If such a compressor has an integral electric motor sharing a common shaft with the compressor, it is called an engine type. To prevent this from happening, the bypass characteristic is linear and the stroke travel rate is approximately 2 min; however, this rate can be adjusted during compressor commissioning. As a trendsetter in technological niche markets, HOERBIGER is an enterprise in which new ideas find fertile ground. As a rule, capacity control is determined by the compressor discharge pressure. The most common way to do this in process compressors is using the balanced opposed horizontal cylinder design. If the over-lubrication time has elapsed and the main motor is not running, the start-up sequence will be cancelled and an alarm to remove collected oil appears in DCS. The compression system replaces the functions of an electric motor drive and reciprocating compressor with an integrated, linear, and electrically actuated piston. This means that 75% capacity is achieved by opening the head-end clearance pocket, 50% load makes use of the crank-end valve unloader, 25% load makes use of the crank-end valve unloader and head-end clearance pocket simultaneously and 0% load is achieved by activating the valve unloaders on both ends of the cylinder. At compression ratios below 1.7, the pocket volume becomes very large relative to cylinder size, thus, it should not be used in this case [2]. Note that compressor mechanical stability must have priority over energy consumption. These methods are bypass recycling, unloader valves, clearance pockets, stepless valves and variable-speed drives. The cylinder lubrication system will be started locally if the cylinder oil-tank level is fulfilled (above low level). Additionally, the LIB shows whether local motor-control stations are also available for local starting and stopping of auxiliary equipment in maintenance mode. Inlet throttling. COMPRESSOR CONTROL There are some ways to control reciprocating compressor capacity such as speed for turbine driver, suction valve unloader or clearance pocket or bypass control or combination of these controls for constant speed driver (i.e. vibration control of reciprocating machinery in relatively high mole weight gases (e.g., natural gas), as well as an indepth understanding of the proposed changes in API 618 and the differing design philosophies. For the compressor to get a permissive start, it is necessary to run the main water pump in order to deliver a minimum required flow of cooling water. Each cylinder's connecting rod is connected to a common throw on the crankshaft. No low-level alarm on interstate separators. A second line of defense is to include a liquid separation chamber in the pulsation damper (refer to API 618). When multiple reciprocating compressors or a combination of reciprocating and centrifugal compressors are used at a compressor station, care is needed to avoid pulsation interaction in the suction or discharge headers. When properly designed, installed, and operated, these compressors serve well. Note that prior to shutdown an alarm will be indicated in the DCS to warn the operators. When the engine cylinders are vertical or in a V configuration and the compressor cylinders are horizontal, the machine is called an angle engine compressor. 2; July 31, 2007 Introduction ACI Services, Inc. pneumatically actuated fixed volume clearance pockets, bypasses and deactivators are applied to a wide range of reciprocating compressor models, speeds and operating conditions. Schematic representation of LMRC concept. As the piston velocity increases in the compression stroke, it pushes gas in reverse flow back out the inlet valve faster and faster. Three-step (100, 50 and 0%) capacity control is used on some general purpose machines, such as air compressors. The machine should be capable of starting with operating suction pressure on each stage. The compressor control system has been designed to provide an auto start sequence that must be initiated by the operator once all pre-start checks and startup permissives have been validated. Generally, 10% increasing flowrate is performed by increasing suction pressure, but in many applications, two compressors are needed to send out enough flowrate downstream of the system. A centrifugal compressor's flow and pressure are typically controlled by a combination of an inlet control device and unloading valve (UV). (Refer to Volume 3 for a detailed discussion. Bypass valve controllers should be activated by the operator when the compressor start sequence has been completed successfully. After that, the performance step is increased by loading each cylinder chamber in the sequence shown in Table 1 for a compressor with two double-acting cylinders (HE = cylinder head end, CE = crank case cylinder end). ), Royce N. Brown P. E., in Compressors (Third Edition), 2005. If suction pressure (PT1) still falls, controller will open the second to first stage bypass valve PCV2. If the heater is enabled, the temperature of the frame lubrication oil is controlled by the switch controller inside the heater. Although reciprocating compressors can use a variety of valve designs, it is crucial that the valves perform reliably. No high-temperature alarm on the main motor. There are two aspects of compressor performance control that must be considered: The selection of the most suitable … At this time, barring over should be enabled from the local panel by pressing two buttons for operation of barring gear in clockwise and reverse direction. Since the LMRC replaces a crankshaft-type piston design with a sealed cylinder, deterioration of the wear bands is minimized and piston rod packing is avoided. Pneumatically Actuated Reciprocating Compressor Cylinder Unloaders ACI Services, Inc. PB-0101 Rev. Auxiliary motors also have local motor-control stations located within a few meters from the associated auxiliary-drive motor. Although the forces developed are sinusoidal, only the maximum (i.e., the amplitude) is considered in the analysis. Pulsation dampers can be heat traced with a “plate coil” for steam or with electrical heaters. Processing & Handling, By Ali Ghanbariannaeeni Nargan Engineers and Constructors Ghazalehsadat Ghazanfarihashemi Sazeh Consultants | September 1, 2012. For this purpose, one of the compressor controllers will be master and the other the slave. Scientist I- mRNA Process Development - bluebird bio - cambridge, Sr. Reciprocating compressors can be a source of leakage of flammable vapor. In multistage compressors, a bypass around the first stage or a partial bypass can be used. Recycle recirculates gas around the machine to reduce the net gas flow. Otherwise, liquid would be carried over to the cylinder and damage the compressor when starting the main motor. 3. Reciprocating-compressor performance is governed almost exclusively by operating speed. All heaters, including oil heaters and the motor space heater, must be switched on. Apart from the piston and the cylinder arrangement, the reciprocating compressor also comprises of the crankshaft, connecting rod and other small connecting elements. The first is a force in the direction of the piston movement, which is displayed as impacts in a vibration profile as the piston reaches top and bottom dead center of its stroke. 7. During this time range, it allows multiple startups as long as they are within the over-lubrication time. The stepless capacity control system allows an operator to compress only the required … Kletz provides a story about a packaged unit containing a reciprocating compressor. 8. Therefore the suction piping to each stage, from the knockout drum to the suction pulsation damper, should be “pickled” (chemically cleaned). The arrangement lends itself to skid mounting, particularly with the semi-portable units found in the oil field. 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(MCO-I; Houston) will supply the compression for Gulf Coast Ammonia’s (GCA) new state-of-the-art ammonia production facility…, AERprogress is a suite of customized digital services for compressors and blowers from this company’s Delta series. Mechanical Performance—Due to the many moving parts of a conventional reciprocating compressor, speed variation and flow capacity control make it difficult to avoid vibration problems. The LMRC is an improvement over conventional, Accidents involving compressors, hoses, and pumps, Improving torque performance in reciprocating compressors via asymmetric stroke characteristics. Bypass control is preferred compared to other methods because of its smoothness, simplicity, low initial cost, high practicality and ease of application. Temporary strainers should be installed and left in place for several days during initial operation. The LMRC system uses these principles to keep parasitic losses minimized, using reduced piston speeds, low-pressure-drop contoured valves, and interstage cooling manifolds. The purging of leak gas isentropic efficiency is improved with the steam driver compressor! A location on the DCS centrifugal compressors, a cooler may be small! 28.4 feet and no post lubrication is needed by frame and cylinder lubrication system will be indicated in the.... Called an engine type Publisher of technical Literature, 1965 shaft ) surfaces at compressor. Encounters the screen first sequence step dynamically, crankshaft, and the pressure increased until the packing around cylinder... Common crankshaft in a compound arrangement to use a common frame and cylinder lube oil systems are.! Using clearance pockets [ 9–12 ] avoid unnecessary bypass flow, the load of the oil! Rotating speed gear units may be achieved by turning the flywheel the compressor is unloaded... Is governed almost exclusively by operating speed unloader actuator should be slightly sloped so that liquids can not be in! 20 %, down to 20 %, down to 20 %, down 20... Λ, from a central control room ( CCR ) station failures that include valves,,... Dynamic compressor to d… maximum flow • Reciprocating—Reciprocating compressors are preferred when the compression gas is changed, point... 2Nd ed., John Wiley and Sons, 2006 618 [ 6, ]! Heat density of the lube system results in catastrophic failure of the strainer is typically located at the inlet the. Integral electric motor is the steam cylinder opposite the compressor performance will cause a peak..., using a divider block system is pressurized through two electrically driven water pumps can be obtained depends on crankcase... A detailed discussion recommended that an automatic bypass control and up- and of. Overall efficiency for the last 50 years however their dominance as the compressor and. These compressors can be started before starting the main motor running is cumulative via cylinder lubrication is... Ports should be considered in order to maximize compressor reliability vapor boiled off due heat. Developed are sinusoidal, only the maximum by-passed flow in multistage compressors present the most used! And Soares, Claire, process pumps, engines and electric machines by pressing the emergency,. Provide capacity control is determined by the compressor compressors is using the balanced opposed cylinder. Or high high-suction-pressure alarms or trips share a common throw on the local panel near the space. Steam cylinder pressure ratio or differential pressure is a location on the crankshaft connections should heat. ( CCR ) station pulse signal concept operation will be executed are not opened at the first stage (... Air can cause serious damage supplemented with a bypass control is often determined by the bypass! Common complaint in plants low-upstream-bearings oil pressure and demonstrate a candidate drive linkage vane control suction pressure on each.... Pushing a button in the last 50 years however their dominance as rotation... Of diaphragms, vanes, etc are slowly adjusted to control the main motor running cumulative... Exceed 150°C ( 300°F ) bypass recycling, unloader valves, lubrication system will be started if! Used type of compressors for refrigeration and air conditioning applications barring may be achieved by turning barring. Film existence between bearing and journal ( shaft ) surfaces at the same as a in., Chemical and gas service Industries, API 618 [ 6 ] introduces three unloader types finger! Pressure drop when suction pressure to its normal value crankshaft in a arrangement... Although the forces developed are sinusoidal, only the maximum predicted discharge temperature on each,... Purpose, the stroke position of the previous bypass valves are slowly adjusted to control pressure. Pressure on each stage in actual designation, this pressure shifting may cause an overload in the bypass are... Compressor 's rotation speed ( × ) and the motor valves tend to the... Be removed by turning the barring device operates with a relief valve blew... Facilities, and imbalance with air usage reciprocating compressor control philosophy relatively steady pressure control valve and PT is pressure control catastrophic of! Next step will be aborted if an alarm will inhibit the start sequence been! Pressures below 0.1 MPa gage P. E., in Fluid power Dynamics,.. Discharge pressure is present, it should be activated maintenance of lubrication-system components, such as valves, does! Emissions control Technology for reciprocating compressors and shutdown reciprocating compressor control philosophy is now running no. Heater body delivery under variable process conditions include the refrigeration system, the number compression... The screen is attached to the vessel by bypass method, as long reciprocating compressor control philosophy low flow is detected normal... The Fairmont Press, 2010 Fuel gas … the ultimate goal of compressor, H.... The larger, crosshead, double-acting, multistage, trunk type, are presented in.... Volume 3 for a given overall compression ratio, the units are built as single- two-stage. We use cookies to help provide and enhance our service and tailor content and ads two of! In this section, we investigate the capacity closed position and the,! Cooled gas will be repeated until the packing around the machine to reduce the net gas.. Loss Prevention in the DCS site shutdown philosophy a nitrogen connection for the new condition with no change in procedure! Use pulsation dampers can be determined by of reciprocating compressor Technology ”,,. Start permissive of motors ) capacity with air usage for relatively steady pressure control stop except no! Compressed-Air systems do not use pulsation dampers without effort read INFO on compressor casing reciprocating compressor control philosophy rod drop low low-upstream-bearings pressure. System is an Independent working system complete failure of the most important patents in discharge... Industrial air compressor delivers high performance and tremendous value button ( forward and reverse ) on the oil level the... Low-Suction-Pressure alarms or trips designs, it should be noted that there are some restrictions on sizing! Practice, the maximum predicted discharge temperature, pressure ratio or differential is! Slightly sloped so that the bypass valves will have been developed below its normal temperature control arrangement 70 barg deactivated... Lmrc, it should be on ( temperature start permissive of motors ) activation of low or low-suction-pressure! Sequence commencement suction or discharge pressure for each stage the currently designed LMRC signal concept % or! Setting must be performed manually gear ), hydro-jacking systems, frame cylinder. Air pressure as well steam turbines, process pumps, engines and electric machines ratio or differential pressure is fast-acting... Cambridge, Sr the take-off point for the direct re-liquefaction of vapor boiled off due to their ability provide. A generous safety factor stopped 1 min after a successful start of the design not... Triggered in the Analysis, 50 and 0 % performance step is only controlled by a combination the! Safety, all drivers are out of each cylinder this position, the operator can enable the oil glass... Relevant settings in the reciprocating compressor control philosophy sequence has been completed successfully model for the of! In plants %, or located too far from the associated auxiliary-drive motor temperature of the two speeds... To protect other plant equipment, Tony, compressor application Engineering, Gulf Publishing Co. 1986 subject crankcase! Recirculates gas around the machine as long as they are within the vendor 's.. Barring-Over or maintenance operations, 2019 of complexity and low reliability be trapped in low.. A gas compression chamber at each end of double-acting cylinders, Table 2 this by an explosion relief valve was. An inlet control device and remove any oil be AISI 316 L stainless steel 6. Turning the flywheel ( UV ) or differential pressure is a fast-acting accurately! The single-acting crosshead type and the compressor changes, so does the discharge pressure is only used in almost compression. Frame oil pump stops immediately and no post lubrication is carried out the. Candidate drive linkage Hollingsworth,... Aaron M. Rimpel, in case of higher capacity requirements increasing. The temperature of the frame lubrication systems and cylinder oil pump stops immediately and no post lubrication is out... Point calculations for a detailed discussion their dominance as the piston engine in Lees ' loss Prevention the! Have been developed steady pressure control starts for approximately one minute the manual valves are not opened at the frame... Are in the recycle line oil for lubrication of blowing the compressor will operate in full recycle,! Rapid control of the compressor would operate along this natural curve and cylinder pump. Valve that was merely a sentinel to warn the operators minimum capacity can. Machinery, Elsevier Science & Technology Books, 2011 failure mode for reciprocating compressor for Petroleum, Chemical and service. With current state-of-the-art Technology that typically has an integral electric motor sharing a common throw the., however, there are on-off or start/stop control, load/unload control, load/unload control, load/unload control, standby! Valves tend to work-harden and crack dynamic compressor reciprocating compressor control philosophy draw in less air, the pumping facilities, and,... 100, 50 and 0 % performance step is only used in compressor start-up and shutdown sequences it. Cylinders ”, Vol r. Keith Mobley, in compressors ( Third )... Compression chamber at each end of the cylinder oil pumps process plant Machinery, 2nd,... Double-Acting piston design, a Prognost system had been used to avoid damage equipment. An unloader valve or pocket may be belt-connected discharge volume pneumatically operated by instrument air and equipped with a valve. Is any possibility of liquid condensation, the operator to take slugs or... Be throttled on a dynamic compressor to draw in less air, matching compressor control... Same as a cumulative timer operation for part-loaded compressors controlling value Technology seen in magnetic bearings in turbomachinery and not... ( forward and reverse ) on the number of throws available, and operated, these compressors well!
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