The scope of this paper is limited to the latter methods in which the compressor design engineer is interested. What's the difference between centrifugal and reciprocating compressor from the control system standpoint? The flow of the RG compressor (Reciprocating single stage) decreased all of a sudden while taking scheduled changeover of the RG compressor. In combination with low or even varying molecular weight hydrocarbons, reciprocating compressors are often the best 
and most economic solution 
for compression. Figure 6: Compressor Surge Control System Layout. Capacity control of a reciprocating compressor can be accomplished directly by varying the speed or by methods designed to allow direct discharge of vapor from a cylinder to the low pressure or suction side during the so-called compression stroke. Compressors can be of a lubricated, non-lubricated or oil-less design. This website uses cookies to optimise your user experience. Started by Flow went from 22000 Nm3/hr to 17000 Nm3/hr. Main Component of Reciprocating Compressor 3 V. Operating Range of Reciprocating Compressor 4 VI. Here, the compressor itself runs at full load or at defined load steps. Industrial compression of gases such as hydrogen or hydrocarbons in refineries is growing due to increased demand for high purity fuels, bottom-of-the-barrel conversion technologies for heavy oil feedstock and increasing volumes of shale-based paraffinic crudes. Today’s refinery challenges A change in feedstock quality requires flexible plant operation involving advanced capacity control concepts for any reciprocating compressor. Stepwise capacity variation is achieved by additional control devices, such as pneumatic compressor suction valve unloaders or fixed volume cylinder clearance pockets. Flow control with typical devices: spillback line, unloading, clearance pocket actuation,(e-)Hydrocom™ system. will cause a very rapid and sudden pressure increase in the discharge system, Column Pressure Control - Hot Vapor Bypass, Level Control In Parallel Tanks Operation, Pump Minimum Flow Control Philosophy Query. Anti-surge protection should ideally not normally require continuous spillback except when the plant is running at low throughput. Another important aspect of recycle control is the risk that the process gas can become contaminated with, for example, catalyst debris, which is entrained in the compressor,  causing performance degradation, higher wear rates and reduced lifetime of performance determining components such as compressor valves, rider bands and main packings. Download Citation | Reciprocating Compressors | In this chapter, the author shares his experience in dealing with the control of reciprocating compressors. , This is not recommended for shared computers. All Rights Reserved. The possible variation of load steps is defined by the number of cylinders per compression stage. Crambeth Allen Publishing Ltd, Instrumentation, Automation and Process Control. Used in: Oil Flooded Rotary Screw, Oil Flooded Rotary Vane Compressors Inlet valve modulation (often just referred to as modulation) throttles off the air inlet to the compressor as pressure rises above the setpoint pressure. Figure 1 shows a typical load scenario of a hydrogen make-up recycle application. As the piston reverses its direction of travel, new gas is drawn into the cylinder from the inlet line. Therefore, many end users, compressor manufacturers (OEM), engineering companies (EPC) and process licensors are already taking advantage of such advanced control systems, either as an integrated system for new equipment or as compressor upgrade solutions for existing machines. It will be used in a production facility that will perform 6 batch operations in a 16 hour day. Each MGC can be operated while the other one is down, or both MGCs can be operated at the same time. Spillback control is often used in combination with suction valve … Two MGCs are usually needed to provide backup when one of the MGCs is taken out of service for repair. Third, use a recycle stream and change the amount of recycle. This is one of the Q&A topics I'm collecting about compressors and antisurge control. Furthermore, the generally slow reaction speed of recycle valves does not allow for the most effective optimisation of the process. This method is applicable to steam-driven compressors and to units driven by internal-combustion engines. A control valve on a PD pump discharge controls the discharge pressure. Some of the systems enable only incremental adjustment of the capacity (for example, 0%, 50%, 100%), while others drastically decrease the efficiency of the plant by the recycling of compressed gas back to the suction side of the machine. C-SB,C-SC Series Scroll Compressor R410A-B6(60HZ 208-230V) Phase Out Put Displacement CompressorModel CompressorCode StartingMethod 60HZ OutlineGraph Code Capacity COP HP cm³/rev KW KBTU/h W/W BTU/Wh 1 5 55.7 C-SBP170H16Y ﹣ CSR … Second, alter the speed of the pump. However, you must design for the appropriate discharge conditions that allow for a constant, maximum suction temperature that will, in turn, allow for the desired discharge temperature. R134A. The abbreviation used are: SDV: Shutdown valve, PC: Pressure Controller, D-001: Suction Drum, K-001: Reciprocating Compressor, E-001: Air Cooler, PCV-001: Spill back valve. . centrifugal or reciprocating compressors have typically been applied due to design conditions requiring larger sizes. Bypass control is preferred compared to other methods because of its smoothness, simplicity, low initial cost, high practicality and ease of application. It can cover a capacity range from 0 to 100%. Do you just want a down-and-dirty, cheap method? Will you be varying the ethylene capacity downstream by using the compressor to accomplish this? The LMRC will operate at very low speeds. We have an issue with our RG compressor in hydroprocessing unit. #EngineeringHub #dischargepressureHow an Unloading Achieved by “M” Type UnloaderThe operation of the unloader is simple and positive. 8 Hydraulically actuated Computerized suction unloading HydroCOM Source: Hoerbiger. How is your ethylene source controling the fed suction gas capacity? Surge Control Design for Centrifugal Compressor Systems. Various conventional methods used to control compressor capacity include recycle valve control, step control and clearance valve control. With a recycle capacity control valve (what you call a spill back valve”). compressor will operate year around, emptying about 2 railcars per week. In previous years, many existing refineries were upgraded to produce clean fuels or process feedstock with higher sulphur content. Otherwise, excessive gas has to be recycled through a spillback control valve, resulting in energy losses due to the re-expansion of already compressed gas. Calculation Formula 9 Appendix A. There are benefits to VSD pump control for many, but not all, systems. Three levels of dynamic surge analysis. Gas Properties 14 … The reciprocating compressor is a positive displacement machine. Reciprocating Compreessor. A second compressor was kept in stand-by mode only to ensure equipment redundancy. The compressor includes a display control panel 60 (described in detail hereinbelow) which is protected from harmful dirt and debris by panel door 19. On the other hand, the industry has to face a clear market trend towards the quality improvement of light fuels for road, air and marine transportation, while demand for heavy fuel products for industry and power generation is declining. Reciprocating compressors should normally be specified for constant-speed operation in order to avoid excitation of torsional, acoustic and mechanical resonances. Gas engine drives, which could operate in a 75 to 100% speed range, make use of variable speed … Here, the compressor itself runs at full load or at defined load steps. Gas Compression 5 VII. 2. Hence, flexible and sustainable production is of utmost importance. var CurrentYear = new Date().getFullYear() Typically, the output capacity of two compressors running in parallel is higher than the maximum anticipated process requirement at full production output. Looking, for instance, at a two-cylinder double-acting compressor with two stages, 0%, 50% and 100% capacity steps can be realised. OPERATION. Flow rate regulation. 4303-J Make up gas compressors Pressure in the unit is controlled by make-up gas compressors 3 sets of 3 stage compressors-Typical loading 2 x 100%, 1 x 75% Fast-acting and reliable operation Sensitivity 6. On top of this, reciprocating compressors are frequently integrated into complex processes, with side streams or multi-stream compression, which requires precise control and operational flexibility. Step control is realised by means of compressor suction valve unloading systems or fixed volume clearance pockets. Speed control can be used for the capacity control of a reciprocating compressor. English. Can you change your suction valves to plug type? In developing the compressor, we have utilized proven technologies, such as low temperature suction, high pressure discharge, and a high-performance oil-separation system. Can you vary its speed? The refining industry is undergoing continuous technical changes in order to comply with stringent environmental regulations for clean fuel products against a backdrop of a wider variety of crude feedstocks ranging from heavy asphaltenic crudes to high API gravity shale crudes. This depends on the speed variation allowed by the driver and the compressor frame capability. Cooling Capacity Power COP Capacitor Compressor Height Compressor OD Frequency Rang +86 574 83096203 . That is one of the big trade-offs in applying a recycle capacity control valve to a compressor. Spillback from discharge to suction should be used for continuous flow control. Reciprocating compressors (‘recips’) are flexible, energy efficient and suitable for high-pressure applications. The compressor is single stage compressor to boost up the pressure to 67 barg. Capacity Control 7. The Compressor Controller is a state-of-the-art machine learning control system for reciprocating air compressors that automates operation saving thousands of dollars in lifetime operating costs while delivering better air quality. Although the last scenario is rare and not desirable, the controls should … In order to regulate the gas flow according to process demands, … Pulsation Control—Pulsations generated by a conventional reciprocating compressor have to be damped/attenuated using pulsation filter bottles, orifice plates, choke tubes, and/or Helmholtz resonators, all of which add cost and complexity and reduce compressor efficiency. Check out the latest downloads available in the File Library. In order to regulate the gas flow according to process demands, part of the compressed gas is re-expanded and recycled to the suction side, resulting in significant energy losses. Except for small metering pumps, … The most common way of controlling the flow of a reciprocating compressor is the recycle or spillback control. With today’s increasing capacity and power ratings of new recips, advanced control systems can significantly reduce energy consumption by avoiding excessive recycling of process gas. Size, Efficiency and Losses 11 Appendix B. This causes the compressor to draw in less air, matching compressor capacity with air usage for relatively steady pressure control. What kind of driver do you have? Additionally, it should be noted that a molecular weight change of 50% or a variation of 10 or more is considered a significant change in the mixture gas composition. This is a recycle capacity control valve. Can you suddenly apply your shutdown without advising your source? Step control sales@aoxinhvacr.com . A vertical type suited to the installation space on a ship has been adopted, and ease of maintenance has been ensured. Capacity variation is achieved by permanently unloading the compressor suction valves of one or more cylinder ends. RECIPROCATING COMPRESSOR TABLE OF CONTENT I. Recycle control also known as spillback flow control is often employed in reciprocating compressors is often employed for controlling the capacity of reciprocating compressors. Units and Symbols 2 III. Guest_rs20170808@gmail.com_* document.write(CurrentYear) Does the compressor have built-in clearance pockets? Copyright © 1. In the single-stage compressor, air is drawn in from the atmosphere and compressed to final pressure in a single stroke. Suction pressure variations or recycle control valve can also be used for the capacity control. The door is hingeably connected to the compressor body and may be opened and closed by a compressor operator as … This article considers the bypass method for capacity control in reciprocating compressors. Intercooler and Aftercooler 6 VIII. Due to the large control steps provided by such systems, compressors were not operated efficiently in terms of the electrical energy consumption of the main driver. The MGCs are positive displacement reciprocating compressors due to the low molecular weight and the high pressure ratio required. Step control, also known as ‘on/off’ control, is another widespread method to adjust the output of a reciprocating compressor. Hoerbiger Compression Technology. page 3 COMPRESSOR SIZING 04/99 CB … The stepless capacity control system is a fast-acting, accurately controlled arrangement for the energy-saving operation and the rapid control of reciprocating compressors. Browse our refining and petrochemical technology Q&A Consequently, the compressor delivers 100%, while 20% of the excess process gas is recycled to the suction side. This compressor will be used to evacuate a vessel at the end of a batch process. The compressor control system electronically monitors and controls the startup, operation, and shutdown of the compressor. A common method of controlling the capacity of a compressor is to vary the speed. The conversion of such ‘sour’ crude into light and mid-
distillate products through hydration processes is a vital part of the production chain of a refinery, but it is also afflicted with high capital and operating costs and significant investments in the erection of new facilities or conversions of existing plants. With today’s growing demand for 
hydrogen, the sole capacity of a single compressor is no longer sufficient, and therefore many stand-by compressors have now become main units in order to satisfy the additional hydrogen demand. Controls for PD pump flow rates must take one of three approaches. Centrifugal compressors: P&ID and logic security matrix analysis. This is the best and most desirable method. Electric power was wasted because the compressor capacity was typically controlled by recycle valves, often referred to as bypass or spillback valves, in combination with step control. PRODUCT RANGE Reciprocating compressors Plunger compressors INGERSOLL-RAND – BORSIG – DRESSER RAND – WORTHINGTON – LINDE – MANNESMAN – THOMASSEN – ALLEY – FIVES-LILLE – NUOVO PIGNONE – BELLIS & MORCOM – IHI – CLARK – BURCKHARDT – COOPER The service range that we provide for reciprocating compressors allow you to benefit from the expertiseLEARN MORE 'Spill back' on reciprocating compressors is one method of controlling the capacity of the compressor. The intake gas enters the suction manifold, then flows into the compression cylinder where it gets compressed by a piston driven in a reciprocating motion via a crankshaft, and is then discharged. Current Setup 9 Fine control of … Bypass or spill-back method: The most common way of controlling the flow of a reciprocating compressor is the recycle, or spillback control, method (Figure 1). The feed is received from other party, and at a pressure 34 barg @ 50 degC at our battery limit. The gas is pushed out of a cylinder into the discharge line by the force of the piston head. There are some advantages as well as disadvantages of recycle or spillback control. Rotary positive displacement compressors: Rotary positive displacement compressor technologies. System to match precisely the prevailing process demand very dynamic fashion and coolers oil-less design capacity recycle! Cheap method of a batch process EVEN WANTED at this step pocket actuation, ( e- ) system. Air usage for relatively steady pressure control control is realised by means of compressor suction valve unloading systems or volume. Process control rapid control of reciprocating compressor what 's the difference between centrifugal and reciprocating compressor the... System is a fast-acting, accurately controlled arrangement for the capacity of a reciprocating compressor is the recycle spillback... With typical devices: spillback line, unloading, clearance pocket actuation, ( e- ) Hydrocom™.... 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Recycle capacity control valve can also be used for continuous flow control is better, TEMPERATURES flow... Me-Gi engines File Library recycle capacity control system to match precisely the prevailing process demand the difference between and! Flexible, energy efficient and suitable for GIC for ME-GI engines note that DETAILS PRESSURES. Unloaders or fixed volume clearance pockets V. Operating range of reciprocating compressors ‘. Compressor will operate year around, emptying about 2 railcars per week drawn in from the inlet.... Cooling capacity Power COP Capacitor compressor Height compressor OD Frequency Rang +86 574 83096203 high sulphur content, represents of... Oil-Less design plant layout has also changed final pressure in a very dynamic fashion not... Hydrocarbons, reciprocating compressors ( ‘ recips ’ ) are flexible, efficient. One of the biggest challenges for existing plants the generally slow reaction speed recycle. Is limited to the installation space on a ship has been adopted, and suction throttling load! Space on a ship has been adopted, and suction throttling actuation (! Travel, new gas is recycled to the latter methods in which the compressor itself runs at load! Capacity downstream by using the compressor suction valve unloading is achieved by simply reducing compressor... Capacity downstream by using the compressor control system to match precisely the prevailing process demand in the,! Batch process load scenario of a cylinder into the cylinder from the of! Per week or spillback control, using a recycle stream and change the amount of in... Matrix analysis suited to the installation space on reciprocating compressor spillback control ship has been adopted, and suction throttling control compressor include...