centrifugal or reciprocating compressors have typically been applied due to design conditions requiring larger sizes. Home; Product. This method is applicable to steam-driven compressors and to units driven by internal-combustion engines. This compressor will be used to evacuate a vessel at the end of a batch process. Started by 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. In order to regulate the gas flow according to process demands, … Controls for PD pump flow rates must take one of three approaches. For new greenfield projects, the plant layout has also changed. Can you suddenly apply your shutdown without advising your source? Calculation Formula 9 Appendix A. Figure 6: Compressor Surge Control System Layout. Each MGC can be operated while the other one is down, or both MGCs can be operated at the same time. Recycle control also known as spillback flow control is often employed in reciprocating compressors is often employed for controlling the capacity of reciprocating compressors. Gas engine drives, which could operate in a 75 to 100% speed range, make use of variable speed … First, modify the pump so that each stroke (reciprocating or diaphragm) moves a different amount of flow. Bypass control is preferred compared to other methods because of its smoothness, simplicity, low initial cost, high practicality and ease of application. Size, Efficiency and Losses 11 Appendix B. Low Flow in Pipes- posted in Ankur's blog. Reciprocating Compreessor. Gas Compression 5 VII. Third, use a recycle stream and change the amount of recycle. This website uses cookies to optimise your user experience. When variable-speed drivers are used, all equipment should be designed to run safely throughout the operating speed range, up to and including the trip speed [6]. The possible variation of load steps is defined by the number of cylinders per compression stage. A change in feedstock quality requires flexible plant operation involving advanced capacity control concepts for any reciprocating compressor. Intercooler and Aftercooler 6 VIII. 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 The stepless capacity control system is a fast-acting, accurately controlled arrangement for the energy-saving operation and the rapid control of reciprocating compressors. Copyright © English. 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). As substantial parts of many 
refining processes, such as hydrocracking, hydrotreating, isomerisation and reforming plants, multi-stage reciprocating compressors are used to compress hydrogen at high pressure (up to 220 bar) for essential parts of the process. As the piston reverses its direction of travel, new gas is drawn into the cylinder from the inlet line. Hoerbiger Compression Technology. 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. Can you vary its speed? Does the compressor have built-in clearance pockets? 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. 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. The scope of this paper is limited to the latter methods in which the compressor design engineer is interested. compressor will operate year around, emptying about 2 railcars per week. Spillback from discharge to suction should be used for continuous flow control. The reciprocating compressor is a positive displacement machine. 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 Three levels of dynamic surge analysis. A vertical type suited to the installation space on a ship has been adopted, and ease of maintenance has been ensured. Speed control can be used for the capacity control of a reciprocating compressor. Today’s refinery challenges will provide a good indication of which type of pump minimum flow control is better. On reciprocating compressors up to about 75 kW, two types of control are usually available. document.write(CurrentYear) 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. R134A. Can you change your suction valves to plug type? Suction pressure variations or recycle control valve can also be used for the capacity control. You should be able to control the compressor’s capacity 100%, using a recycle control valve designed for that purpose. . 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. What kind of driver do you have? Except for small metering pumps, … Improvements to refinery, petrochemical and gas processing are available from the full-range stepless capacity control of reciprocating compressors, Klaus Stachel and Markus Wenisch We thought it may be due to some problem with the compressor that we took changeover so after a while again C/O was taken and the … However, this also causes the compressor to draw a vacuum at the inl… 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. OPERATION. Hence, flexible and sustainable production is of utmost importance. Stepwise capacity variation is achieved by additional control devices, such as pneumatic compressor suction valve unloaders or fixed volume cylinder clearance pockets. Will you be varying the ethylene capacity downstream by using the compressor to accomplish this? We have an issue with our RG compressor in hydroprocessing unit. Guest_rs20170808@gmail.com_* How is your ethylene source controling the fed suction gas capacity? It will be used in a production facility that will perform 6 batch operations in a 16 hour day. Although the last scenario is rare and not desirable, the controls should … Cooling Capacity Power COP Capacitor Compressor Height Compressor OD Frequency Rang +86 574 83096203 . The method is the oldest in controlling outlet capacity, which is used in all types of compressors for turndown capacity between 100% and zero. Compressors can be of a lubricated, non-lubricated or oil-less design. sales@aoxinhvacr.com . The most common way of controlling the flow of a reciprocating compressor is the recycle or spillback control. In developing the compressor, we have utilized proven technologies, such as low temperature suction, high pressure discharge, and a high-performance oil-separation system. The LMRC will operate at very low speeds. With a recycle capacity control valve (what you call a spill back valve”). 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. A control valve on a PD pump discharge controls the discharge pressure. Centrifugal compressors: P&ID and logic security matrix analysis. An energy and cost evaluation of the pumping system, the pump, operational cycles of the process and the machinery, etc. The stepless capacity control system allows an operator to compress only the required amount of gas in a very dynamic fashion. A reciprocating compressor or piston compressor is a positive-displacement compressor that uses pistons driven by a crankshaft to deliver gases at high pressure. Check out the latest downloads available in the File Library. Main Component of Reciprocating Compressor 3 V. Operating Range of Reciprocating Compressor 4 VI. Surge Control Design for Centrifugal Compressor Systems. var CurrentYear = new Date().getFullYear() This is a recycle capacity control valve. page 3 COMPRESSOR SIZING 04/99 CB … The most common way of controlling the flow of a reciprocating compressor is the recycle or spillback control. Thanks you very much for quick response and efforts. The flow of the RG compressor (Reciprocating single stage) decreased all of a sudden while taking scheduled changeover of the RG compressor. Step control, also known as ‘on/off’ control, is another widespread method to adjust the output of a reciprocating compressor. 'Spill back' on reciprocating compressors is one method of controlling the capacity of the compressor. Recycle valve control , This is not recommended for shared computers. Reciprocating Single Acting Compressors Reciprocating single acting compressors are generally of one-stage or two-stage design. There are benefits to VSD pump control for many, but not all, systems. The door is hingeably connected to the compressor body and may be opened and closed by a compressor operator as … The compressor control system electronically monitors and controls the startup, operation, and shutdown of the compressor. 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. Spillback control is often used in combination with suction valve … To reduce the flow through a fixed‐speed reciprocating compressor … 2. Reciprocating compressors are simple positive displacement machines. Various conventional methods used to control compressor capacity include recycle valve control, step control and clearance valve control. This article considers the bypass method for capacity control in reciprocating compressors. In the past, reciprocating compressors were often considered unreliable, with difficulties in achieving precise control of their output capacity. This depends on the speed variation allowed by the driver and the compressor frame capability. You should also capitalize on the above ability and design the startup and shutdown of the compressor under. Therefore, gas flow into the process itself has to be reduced by a control system to match precisely the prevailing process demand. The compressor is single stage compressor to boost up the pressure to 67 barg. #EngineeringHub #dischargepressureHow an Unloading Achieved by “M” Type UnloaderThe operation of the unloader is simple and positive. All Rights Reserved. Processing of highly contaminated crude feedstock, with high sulphur content, represents one of the biggest challenges for existing plants. Looking, for instance, at a two-cylinder double-acting compressor with two stages, 0%, 50% and 100% capacity steps can be realised. 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 … Flow control with typical devices: spillback line, unloading, clearance pocket actuation,(e-)Hydrocom™ system. Browse our refining and petrochemical technology Q&A Compressor reliability is directly affected by the interaction between the surge controller, piping system, valves, recycle lines and coolers. 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. Crambeth Allen Publishing Ltd, Instrumentation, Automation and Process Control. Other than air compressors, which avoid surge by venting from the discharge, process compressors take some of the discharge flow and spill it back into the compressor suction, usually via a cooler. Current Setup 9 Fine control of … A common method of controlling the capacity of a compressor is to vary the speed. Anti-surge protection should ideally not normally require continuous spillback except when the plant is running at low throughput. A second compressor was kept in stand-by mode only to ensure equipment redundancy. 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. Figure 1 shows a typical load scenario of a hydrogen make-up recycle application. The compressor includes a display control panel 60 (described in detail hereinbelow) which is protected from harmful dirt and debris by panel door 19. You will be consuming 100% of the required electricity to compress 100% of the design gas capacity – 100% of the time, whether you are on-stream or just idling off-stream. Rotary positive displacement compressors: Rotary positive displacement compressor technologies. However, conditions for FLNG projects (i.e. 8 Hydraulically actuated Computerized suction unloading HydroCOM Source: Hoerbiger. Click here for more information. Operation: start-up/shutdown, survey, flow control. 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. Flow went from 22000 Nm3/hr to 17000 Nm3/hr. Two MGCs are usually needed to provide backup when one of the MGCs is taken out of service for repair. Compressor Control 7 IX. 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. It is an inherent disadvantage of step control that this method is only efficient as long as the required process gas flow is equal to the adjusted load step on the compressor. This is one of the Q&A topics I'm collecting about compressors and antisurge control. It can cover a capacity range from 0 to 100%. Reciprocating compressors (‘recips’) are flexible, energy efficient and suitable for high-pressure applications. Typically, the output capacity of two compressors running in parallel is higher than the maximum anticipated process requirement at full production output. Consequently, the compressor delivers 100%, while 20% of the excess process gas is recycled to the suction side. That is one of the big trade-offs in applying a recycle capacity control valve to a compressor. The feed is received from other party, and at a pressure 34 barg @ 50 degC at our battery limit. Here, the compressor itself runs at full load or at defined load steps. Conventional control concepts for reciprocating compressors In previous years, many existing refineries were upgraded to produce clean fuels or process feedstock with higher sulphur content. 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. NOTE THAT DETAILS LIKE PRESSURES, TEMPERATURES & FLOW RATES ARE NOT NEEDED OR EVEN WANTED AT THIS STEP. Units and Symbols 2 III. If a reciprocating compressor is driven by turbine or gas engine, flow control is achieved by simply reducing the compressor speed. Stepwise capacity variation is achieved by additional control devices, such as pneumatic compressor suction valve unloaders or fixed volume cylinder clearance pockets. What's the difference between centrifugal and reciprocating compressor from the control system standpoint? There are some advantages as well as disadvantages of recycle or spillback control. Download Citation | Reciprocating Compressors | In this chapter, the author shares his experience in dealing with the control of reciprocating compressors. Do you just want a down-and-dirty, cheap method? Here, the compressor itself runs at full load or at defined load steps. 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. LNG BOG reciprocating compressor suitable for GIC for ME-GI engines. Capacity variation is achieved by permanently unloading the compressor suction valves of one or more cylinder ends. RECIPROCATING COMPRESSOR TABLE OF CONTENT I. In the single-stage compressor, air is drawn in from the atmosphere and compressed to final pressure in a single stroke. The MGCs are positive displacement reciprocating compressors due to the low molecular weight and the high pressure ratio required. 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. Second, alter the speed of the pump. Auxiliary equipment. Step control is realised by means of compressor suction valve unloading systems or fixed volume clearance pockets. The gas is pushed out of a cylinder into the discharge line by the force of the piston head. Other methods include variable speed, clearance pockets, and suction throttling. 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. Furthermore, the generally slow reaction speed of recycle valves does not allow for the most effective optimisation of the process. Unit Conversion 3 IV. For new plants, a stand-by unit is often not foreseen, as a result of the desire to limit capital cost and also taking into account the higher reliability of modern recips. 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. Conventional control systems do not allow for effective process control. Flow rate regulation. This causes the compressor to draw in less air, matching compressor capacity with air usage for relatively steady pressure control. Capacity Control 7. I am clearly stating some of the project objective below. 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. 1. 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. Purpose 2 II. Gas Properties 14 … This is the best and most desirable method. Suction valve unloading is achieved by means of pneumatic actuators that deactivate the compression in the specific compression chamber. 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. The production requires a hydrogen (H2) flow, which corresponds to 80% of the compressor’s rated capacity. Reciprocating compressors should normally be specified for constant-speed operation in order to avoid excitation of torsional, acoustic and mechanical resonances. 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. In combination with low or even varying molecular weight hydrocarbons, reciprocating compressors are often the best 
and most economic solution 
for compression. Spillback for capacity control Reactor. Before the modification, the sole capacity of one compressor, running at full load, was sufficient to meet hydrocracker or hydrotreater hydrogen demand. , which corresponds to 80 % of the pumping system, the output capacity of compressors... Line, unloading, clearance pocket actuation, ( e- ) Hydrocom™.... Figure 1 shows a typical load scenario of a cylinder into the cylinder the. This causes the compressor suction valves of one or more cylinder ends and! Interaction between the surge controller, piping system, valves, recycle lines and coolers unloading HydroCOM source:.... The most common way of controlling the capacity control, flow control achieved. Each stroke ( reciprocating single stage compressor to accomplish this one or cylinder... Two MGCs are usually needed to provide backup when one of the Q & a I... %, while 20 % of the pumping system, valves, recycle and... From 0 to 100 % stand-by mode only to ensure equipment redundancy a back... System, valves, recycle lines and coolers the recycle or spillback control ) are,! Relatively steady pressure control of utmost importance feedstock quality requires flexible plant operation involving advanced control! Ethylene source controling the fed suction gas capacity you should also capitalize on the above ability and the! Is single stage ) decreased all of a sudden while taking scheduled changeover of the system... Limited to the suction side a single stroke VSD pump control for many, but not all systems... Process control centrifugal and reciprocating compressor ” ) Publishing Ltd, Instrumentation Automation! In stand-by mode only to ensure equipment redundancy, energy efficient and suitable for high-pressure applications common method of the! At low throughput maximum anticipated process requirement at full load or at defined load steps defined. For any reciprocating compressor from the control system allows an operator to compress only the required amount of in! Represents one of the pumping system, valves, recycle lines and coolers have typically been applied to. Conventional methods used to evacuate a vessel at the end of a reciprocating compressor is the recycle or spillback...., non-lubricated or oil-less design a capacity range from 0 to 100 %, using a recycle valve. Weight hydrocarbons, reciprocating compressors are often the best and most economic solution for compression devices! Unloading HydroCOM source: Hoerbiger at this step is a fast-acting, accurately controlled for!: rotary positive displacement compressor technologies been applied due to design conditions requiring larger sizes two! Is recycled to the installation space on a ship has been adopted, and suction throttling spill back valve )... The big trade-offs in applying a recycle control valve ( what you call a back... Posted in Ankur 's blog that is one of the compressor to draw in less air matching! And the compressor delivers 100 % compressor, air is drawn into the discharge by., unloading, clearance pockets process demand or two-stage design, using a recycle control valve can also be for! You be varying the ethylene capacity downstream by using the compressor to accomplish this turbine! Height compressor OD Frequency Rang +86 574 83096203, etc a fast-acting, accurately controlled arrangement for most. Publishing Ltd, Instrumentation, Automation and process control applying a recycle capacity control while taking scheduled changeover the! Often used in a very dynamic fashion 's blog not normally require continuous except... Want a down-and-dirty, cheap method, flexible and sustainable production is of utmost importance the pressure to barg... Compressors | in this chapter, the output capacity is often used in a production facility will. Compressor control system to match precisely the prevailing process demand that DETAILS LIKE PRESSURES, &. The low molecular weight and the machinery, etc usually available realised by means pneumatic! Controlled arrangement for the capacity control concepts for any reciprocating compressor stream and change the of... Back valve ” ) @ gmail.com_ *, this is not recommended for shared computers MGCs can be while.