Read ER-56.04.FM text version

RECIPROCATING PACKAGER'S STANDARDS

SECTION 4 - PIPING, PRESSURE TESTING AND RELIEF VALVES

Scrubbers shall be designed and installed, and the package constructed by the Packager so that:

1. Each compressor cylinder must have a scrubber or some other liquid removal device immediately ahead of each stage for the removal of both free and entrained liquids from the gas. The scrubber must have a high liquid level protection system and a drain system. Sight glasses are recommended. It is the packager's responsibility to provide a system that meets the application requirements. Scrubbers should be designed and constructed in accordance with good engineering practice and industry standards for two-phase separators and pressure vessels. API 11P is a good source for determining the scrubber specifications. Scrubbers should be supported directly by full depth structural members. Support from a plate spanning members typically is not sufficient.

The contents of this document are proprietary and confidential. They are the property of Ariel Corporation and may not be disclosed, reproduced, or used for manufacture in part or in whole without written permission from Ariel Corporation.

2. 3.

Piping shall be designed and installed and the Package constructed by the Packager such that:

1. 2. The piping shall not have a low point that could collect liquids between the scrubber and cylinder. Liquid slugging and subsequent compressor damage will occur. The piping should be designed and constructed so it does not distort the cylinders and/or crosshead guide when installed. Crosshead-to-guide clearance should be checked after the installed unit is connected to the end user's piping to confirm the piping imposes no distortion. Piping should be straightforward in its arrangement and of sufficient size and design to provide equal flow to cylinders in parallel. Piping should be designed and constructed in accordance with good engineering practice and industry standards regarding pressure and temperature rating, flow velocity, pressure drop, and materials compatible with the gas stream. Prior to start-up, cone type inlet gas debris strainers with 100 mesh per inch (150 micron) screen and perforated metallic backing are to be installed in a pipe spool between the inlet scrubber and cylinder suction flange. In order to protect the compressor cylinder, any piping or vessels downstream of the screen must

4 015484 013714 012609 011017 ECN8100 EC 9-29-08 7-10-06 3-30-05 9-3-04 2-23-00 DATE REV EC DATE 3 2 1

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Page 3, para. 1. updated to ISO-13631.

DESCRIPTION

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ER-56.04

RECIPROCATING PACKAGER'S STANDARDS be thoroughly cleaned to ensure that no debris is present. Proper maintenance of the inlet screens is required. Inlet debris strainers should be monitored by differential pressure and cleaned before the differential pressure approaches the collapse pressure of the screens. High differential pressure alarm/shutdown switches can be used to protect against screen collapse. Piping should be supported and clamped in accordance with good engineering practice. Supports shall be attached directly to, or directly supported by a structural member of the skid or foundation. Support from deck plate is not sufficient. Unistrut type clamps are not sufficient. Band clamps should be used. Fabreeka or an equivalent material should be used between the clamp and pipe to prevent fretting and corrosion. Piping should be checked to be sure that it is resting on the support, not pulled down by the clamp. It should be shimmed if necessary.

6.

7. 8.

Pulsation Bottles

1. It is the Packager's responsibility to determine whether or not pulsation bottles are required for a particular service, if not already determined by the customer's specifications. Determining if acoustical or mechanical resonance exists and taking corrective action is the Packager's responsibility. Single acting cylinder and cylinder unloading-steps operating cases must be considered when analyzing torsional responses and acoustical pulsation responses. Single acting cylinders can present the worst case scenario for torsional analysis due to a more dynamic torque effort curve, and for an acoustical pulsation analysis due to a change in the number of pulses per cycle. High torsional vibration and/or high acoustically driven vibration can result from single acting cylinder operation when not considered in these analyses. High acoustical pulsation can increase frame, cylinder, gas piping and equipment vibrations. If information is required beyond that found in the Application Data Book, please contact Ariel. In the event pulsation bottles are used, they should be designed and constructed in accordance with good engineering practice and industry standards for either piping and/or pressure vessels. Pulsation bottles must be designed so they do not have traps, which allow liquids to accumulate and then go through a compressor cylinder in large volumes. Compressors can be severely damaged by liquids. Taps for drains and instruments shall be provided on the bottles. The tap locations for temperature and pressure connections must be as close to the compressor cylinder as possible. The discharge temperature shutdown probe should be in the 1/2" NPT tap provided by Ariel in the cylinder discharge nozzle, where applicable. Pulsation bottles connecting two or more cylinders are to be constructed so as not to strain the cylinder flange connections or distort the cylinders. Reinforcement pads and/or gussets are recommended for nozzle reinforcement, regardless of code requirements. Bottle supports are not required if the following conditions are maintained: Piping and bottles are constructed and assembled so they put no strain on the cylinder flanges while the compressor is in operation. REV 4 ER-56.04

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The contents of this document are proprietary and confidential. They are the property of Ariel Corporation and may not be disclosed, reproduced, or used for manufacture in part or in whole without written permission from Ariel Corporation.

RECIPROCATING PACKAGER'S STANDARDS The crosshead guide mounting feet are firmly supported and properly aligned. Piping is properly tied down. There are no scrubbers or piping or any other attachments to the skid vibrating at a natural frequency while the compressor is in operation. 8. If bottle supports are used, it is imperative that they be properly adjusted when the compressor is at operating temperature so they put no strain on the compressor cylinders. Support adjustments should be checked frequently. Inattention to bottle support adjustment will result in premature failure of compressor parts.

Relief Valves

1. It is the responsibility of the packager to provide relief valves for every stage of compression (and set to operate) in compliance with ISO-13631. Relief valve location and settings, including accumulation, shall take into consideration all possible types of equipment failure, mal-operation and the protection of piping systems. Rated discharge pressure (RDP) is the highest pressure required to meet the conditions specified by the purchaser for the intended service. The RDP values listed in the Ariel Performance Program are obtained by dividing the MAWP by 1.10 or subtracting 25 psi (1.7 bar), whichever results in the lower RDP. The Packager must install a relief valve immediately downstream of the by-pass valve or on the initial stage scrubber, set for not more than the MAWP of the initial stage cylinder and sized for maximum by-pass volume. The Packager shall require that the relief valve settings as well as the cylinder and component MAWP's must be adequate for the process settling-out pressures during shutdown. When a relief valve is connected to a vent header, it must have back-flow protection.

2. 3. 4.

CAUTION: THE COMPRESSOR CYLINDER MAY OR MAY NOT BE THE SYSTEM COMPONENT WITH THE LOWEST PRESSURE RATING. THE RELIEF VALVE SHOULD BE SET BASED ON THE LOWEST RATED PIECE OF CONNECTED EQUIPMENT.

Vents, Tubing and Piping

The Packager is responsible for venting the units in a safe manner. The Packager shall provide auxiliary piping vents and drains as follows: 1. 2. A blow-down vent must be provided to safely relieve pressure from the system for maintenance purposes. Any vent or blowdown line connected to a common vent or flare header must have a back-flow prevention check valve. Adequate vents and drains will be provided for the distance piece, and primary packing vent. Primary vents and drains shall be independently vented from the secondary vents and drains. All vents and drains shall be installed in such a manner as to prevent the collection of liquids that could cause the build-up of REV 4 ER-56.04

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The contents of this document are proprietary and confidential. They are the property of Ariel Corporation and may not be disclosed, reproduced, or used for manufacture in part or in whole without written permission from Ariel Corporation.

RECIPROCATING PACKAGER'S STANDARDS either gas or liquid. When a heavier than air gas is involved, vent and drain design must be accommodating. When the crankcase breather is mounted remotely, the piping must be configured so that condensation in the piping does not drain into the crankcase. There must be access (without interfering piping or conduit) to the analyzer drive connection at the crankshaft centerline on the auxiliary end of the crankcase. There must be visual access to the crankcase oil level sight glass and the cycle indicator on the distribution block. Great care must be taken during piping and fabrication to ensure grinding dust, weld slag; sand and rain do not get inside the compressor. Special care must be used on cylinder lubrication tubing, which is done in the field. It must be clean and free of tubing cuttings. The ground connection, when welding on the skid, should be close to the weld and never attached to the compressor. Lube oil piping from the filter to the frame that is modified or removed by the Packager, must be pickled or given an equivalent cleaning before reinstallation. NO foreign matter shall remain in the piping. It is recommended that stainless tubing be installed between the oil filter and crankcase header connection.

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ER-56.04

The contents of this document are proprietary and confidential. They are the property of Ariel Corporation and may not be disclosed, reproduced, or used for manufacture in part or in whole without written permission from Ariel Corporation.

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ER-56.04.FM

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