IOGP & JIP33, S-612 Air Compressor : 6 Basic Design (1/4)

Supplementary Specification to API Standard 672 Packaged, Integrally Geared Centrifugal Air Compressors

요약
- API 672 4th에 적용 (현재는 API 5th 이 나와있음)
- Shaft power 1500kW에 해당되는 공기 압축기에 적용
- 6.1.9  The thermodynamic performance test may be performed on one machine of multiple order of identical machines.

---

Acknowledgements
This IOGP Specification was prepared by a Joint Industry Project 33 Standardization of Equipment Specifications for Procurement organized by IOGP with support by the World Economic Forum (WEF).

Foreword
This specification was prepared under a Joint Industry Project 33 (JIP33) “Standardization of Equipment Specifications for Procurement” organized by the International Oil & Gas Producers Association (IOGP) with the support from the World Economic Forum (WEF). Ten key oil and gas companies from the IOGP membership participated in developing this specification under JIP33 Phase 2 with the objective to leverage and improve industry level standardization for projects globally in the oil and gas sector. The work has developed a minimized set of supplementary requirements 
for procurement, with life cycle cost in mind, based on the ten participating members’ company specifications, 
resulting in a common and jointly approved specification, and building on recognized industry and/or international 
standards.
This specification has been developed in consultation with a broad user and supplier base to promote the opportunity to realize benefits from standardization and achieve significant cost reductions for upstream project costs. The JIP33 work groups performed their activities in accordance with IOGP’s Competition Law Guidelines (November 2014).

Recent trends in oil and gas projects have demonstrated substantial budget and schedule overruns. The Oil and Gas Community within the World Economic Forum (WEF) has implemented a Capital Project Complexity (CPC) initiative which seeks to drive a structural reduction in upstream project costs with a focus on industry-wide, non- competitive collaboration and standardization. The vision from the CPC industry is to 
standardize specifications for global procurement for equipment and packages, facilitating improved standardization of major projects across the globe. While individual oil and gas companies have been improving standardization within their own businesses, this has limited value potential and the industry lags behind other industries and has eroded value by creating bespoke components in projects.
This specification aims to significantly reduce this waste, decrease project costs and improve schedule through pre competitive collaboration on standardization. This document defines the supplementary requirements to recognized international standard API standard 672 4th Edition 2004, integrally geared centrifugal air compressors for petroleum, chemical and gas industry service, which is indispensable for the application of this specification.

Following agreement of the relevant JIP33 work group and approval by the JIP33 Steering Committee, the IOGP Management Committee has agreed to the publication of this specification by IOGP. Where adopted by the 
individual operating companies, this specification and associated documentation aims to supersede existing company documentation for the purpose of industry harmonized standardization.

 

 

 

Introduction

The purpose of this specification is to define a minimum common set of supplementary requirements for procurement of packaged, integrally geared centrifugal air compressors in accordance with API standard 672 4th 
Edition 2004 for application in the petroleum and natural gas industries.

This JIP33 standardized procurement specification follows a common document structure comprising the four documents as shown below, which together with the purchase order define the overall technical specification for procurement.

 

 

It is required to use all of these documents in conjunction with each other when applying this specification, as follows:

S-612: Supplementary specification to API Standard 672 for Packaged, Integrally Geared Centrifugal Air Compressors
This specification is written as an overlay to API Std 672, following the clause structure of the parent standard, to assist in cross-referencing the requirements. Where clauses from the parent standard (API Std 672) are not covered in this specification, there are no supplementary requirements or modifications to the respective clause. The terminology used within this specification follows that of the parent standard and otherwise is in accordance with ISO/IEC Directives, Part 2.

Modifications to the parent standard defined in this specification are identified as Add (add to clause or add new clause), Replace (part of or entire clause) or Delete.

S-612D: Data sheets for Packaged, Integrally Geared Centrifugal Air Compressors
This document provides project specific requirements where the supplementary specification and its parent standard require the purchaser to define an application specific requirement. It also includes information required by the 
purchaser for technical evaluation. Additional purchaser supplied documents are also listed in the data sheets, to define scope and technical requirements for enquiry and purchase of the equipment.

S-612L: Information requirements for Packaged, Integrally Geared Centrifugal Air Compressors
This document defines the information requirements, including format, timing and purpose, for information to be provided by the vendor. It also defines the specific conditions which must be met for conditional information 
requirements to become mandatory. The information requirements listed in the IRS have references to the source of the requirement.

S-612Q: Quality requirements for Packaged, Integrally Geared Centrifugal Air Compressors
This document includes a conformity assessment system (CAS) which specifies standardized user interventions against quality management activities at four different levels. The applicable CAS level is specified by the purchaser 
in the data sheets.

The data sheet and IRS are published as editable documents for the user to specify application specific requirements. The supplementary specification and QRS are fixed documents.

Unless defined otherwise in the purchase order, the order of precedence (highest authority listed first) of the documents shall be:
a) regulatory requirements;
b) contract documentation (e.g. purchase order);
c) purchaser defined requirements (data sheets, IRS, QRS);
d) this specification;
e) the parent standard.

1 Scope
1.1
Add to section
This specification covers constant speed electric motor driven integrally geared centrifugal air compressor, with a shaft power range of up to 1500 kW, for plant and instrument air application.

Note: This specification may also be applied for a steam turbine driven air compressor package. However, the requirements for the steam turbine driver are not covered within this specification.

1.2
Add to section
This specification is applicable for basic duty packages, using the proven vendor's standard design.
Note: The compressor is assumed to be spared.

6 Basic Design
6.1 General
Add to section
6.1.3 Sound Pressure Level
The A-weighted sound pressure level, for the compressor unit at rated duty under free field operating conditions, shall be limited within the noise limit specified in the data sheet.

Sound pressure level measurement shall be taken at 1.0 m (3.3 ft) from the skid boundary and at 1.0 m (3.3 ft) from the discharge blow-off silencer outlet.

6.1.4 Packaged Equipment
Replace section with
The scope of the compressor package shall include, as a minimum, the following:
a. Integrally geared centrifugal air compressor
b. Compressor gear box breather and screen
c. Main drive coupling and coupling guard
d. Main driver
e. Inlet air filter and silencer with weather hood and support leg
f. Variable inlet guide vane
g. Discharge blow-off valve and silencer
h. Inlet and discharge expansion joint
i. Blow-off line expansion joint for off-skid blow-off valve and silencer
j. Intercoolers and aftercooler
k. Moisture separator and automatic drainer, or drain traps
l. Lube oil system (common) for compressor, gear and driver with lube oil reservoir including demister, lube oil filter, lube oil pump (main and auxiliary including coupling and driver for auxiliary lube oil pump), lube oil heater complete with piping, valves and instrumentation
m. On-skid interconnecting piping, fitting and valves including control valves and pressure relief valves, as applicable
n. Control, monitoring and protection instruments with on-kid instruments, control panel, control, signal and power cables, and junction box
o. Noise attenuation device such as acoustic insulation and noise enclosure to meet required noise limit
p. Skid baseplate with lifting lugs
q. Local emergency stop push button.
For off-shore installation, the compressor package shall be a complete unit installed on a single skid.

6.1.5 Environmental Conditions
Add to section
The compressor package shall be suitable for outdoor installation with ambient conditions as specified in the data sheet.
Any additional requirements for weather protection, such as enclosure, winterization, topicalization based on any special site, or environmental conditions shall be specified in the data sheet.

6.1.6 Cooling Water Systems
Add to section
For alternative cooling medium, the fouling factor specified in the data sheet, shall be used.
The cooling water maximum inlet temperature specified in the data sheet, based on project environmental maximum ambient conditions shall be used.

6.1.7 Package Arrangement
Add new section
6.1.7.4
The package shall conform to skid envelope dimension limits, as specified in the data sheet.
Add new section

6.1.7.5
If specified by the purchaser, the intake opening shall be located opposite to the prevailing wind direction.

The vendor shall propose the location and orientation of the air intake. The purchaser shall verify the proposed location and orientation with respect to exhaust gas emissions from nearby equipment.

6.1.8
Motors and Electrical Components
Replace first sentence with
Motors, electrical components, and electrical installations shall be suitable for the area classification (class, group, and division or zone) specified by the purchaser and shall meet the requirements of the applicable sections of IEC 60079 or NFPA 70, Articles 500, 501, 502, and 504, as well as local codes.
Add new section

6.1.8.1
Unless otherwise specified in the data sheet, motors and other electrical components shall be rated for safe area application.
Add new section

6.1.8.2 Unless otherwise specified in the data sheet, the compressor skid shall be non-Ex zone certified.

6.1.9 Performance Criteria
Add to section
Compressor thermodynamic and mechanical performance, as specified in the data sheet, shall be validated by the vendor during the performance and mechanical run tests. The thermodynamic performance test may be performed on one machine of multiple order of identical machines.

6.1.10 Purchaser Connections
Replace first sentence with
All openings or nozzles for purchaser connection shall be DN 20 (NPS 3/4) or larger in accordance with ISO 6708. Add new section

6.1.10.1
Nozzles for purchaser connections larger than DN 50 (NPS 2) shall be flanged per ASME B16.5.
Add new section

6.1.10.2
Nozzles for purchaser connections smaller than DN 50 (NPS 2) may be threaded per ASME B1.20.1 or flanged.
Add new section

6.1.10.3
Proprietary connection types shall not be used for purchaser connections unless specifically approved by the purchaser.

6.1.12 Compressor Performance
6.1.12.1
Add to section
The turn down capacity shall be at least 15 % less than the rated capacity.

6.1.13 Mounting Surfaces
Replace first sentence with
Mounting surfaces shall meet the following criteria:
Add to section
When shims are used under the driver mounting pad, they shall be full-face stainless steel shims.

6.2 Pressure Casings
6.2.2 Add to section
The maximum discharge pressure shall not be less than the discharge pressure based on maximum rotational speed. Add new section

6.2.4
Jackscrews, guide rods, cylindrical casing-alignment dowels or other necessary devices shall be provided to allow disassembly and reassembly.
Add new section

6.2.4.1
When jackscrews are used as a means of parting contacting faces, one of the faces shall be relieved (counter bored or recessed) to prevent a leaking joint or improper fit caused by marring of the face.
Add new section

6.2.4.2
Guide rods shall be of sufficient length to prevent damage to the internals or casing studs by the casing during disassembly and reassembly.
Add new section

6.2.5
Lifting lugs or eyebolts shall be provided for lifting the top half of the gear casing.

6.3 Casing Connections
Add new section

6.3.10
The package shall be provided with means of draining of compressor casing.
6.5 Rotating Elements
6.5.1 Shafts
6.5.1.5
Add new section
For shafts with keyways, ISO 21940-32 shall be followed for shaft and fitment key conventions.

6.5.2 Impellers
6.5.2.2
Add to section
Impeller construction and attachment method shall ensure positive retention of the impeller-to-shaft connection with necessary locking arrangement to prevent impeller loosening in service, especially during start-up, over speed, reverse rotation and surge events.

6.6 Seals and Sealing System
6.6.3
Add to section
If specified in the data sheet, a buffered-seal design shall be provided for compressors.

6.7 Dynamics
6.7.1 Critical Speeds
6.7.1.4
Replace section with
For the purposes of this standard, critical speeds and other resonant conditions of concern are those with an amplification factor (AF) equal to or greater than 2.5.

6.7.2 Lateral Analysis
Replace second sentence with
A report is not required, unless specified in the data sheet. The vendor shall specify lateral critical speed values in the data sheet.

6.7.3 Torsional Analysis
6.7.3.1
Replace second sentence with
A report is not required, unless specified in the data sheet. The vendor shall specify torsional natural frequencies in the data sheet, based on the drive train supplied.

6.7.4 Vibration and Balancing
Add new section
6.7.4.4
Rotor assembly shall be dynamically balanced to balance grade G1 as per ISO 21940-11.
Add new section
6.7.4.5
The total combined electrical and mechanical runout shall not exceed 6.35 μm (0.25 mils).

6.8 Bearings and Bearing Housings
6.8.1 Bearings – General
6.8.1.1
Replace section with
If approved by the purchaser, anti-friction bearings may be used only for low speed bull gear shaft rotors. Rolling element bearings shall not be used on pinion shaft rotors.
Add new section
6.8.1.3 
Basic rating life (L10 bearing life) for anti-friction bearing, as defined in ISO 281, shall be 50000 hours or more.

6.9 Lubrication
Add new section heading
6.9.5 Lube Oil Cooler
Add new section
6.9.5.1 When an air-cooled design is specified for lube oil cooler, oil shall be cooled in a single bay two fan air-cooled unit. The tube bundle design shall be per TEMA Class C as a minimum, with header box design to be of the removable cover plate, removable bonnet or plug type construction.
Add new section

6.9.5.2
The heat exchanger materials shall comply with Table 4.
Add new section heading
6.9.6 Lube Oil Filter
Dual filters shall be provided, each sized for 100 % of the flow as a minimum.
Add new section
6.9.6.1
The filters shall be designed for on-line change-over and on-line replacement of the off-line unit.
Add new section
6.9.6.2
The filters shall be equipped with a differential pressure local indicating transmitter.
Add new section
6.9.7
Lubrication system design shall guarantee priming of the main oil pump prior to compressor start-up.
Add new subheading
6.9.8 Lube Oil Reservoir
Add new section
6.9.8.1
Lube oil reservoir capacity shall be based on minimum 3 minutes retention time. Retention time less than 3 minutes shall be subject to the purchaser’s approval.
Add new section
6.9.8.2
A temperature controlled electric immersion heater shall be provided.

6.10 Materials
Add new section heading
6.10.6 Material Selection
Add new section
6.10.6.1
Material selection requirements shall be in accordance with this specification and the mechanical data sheet for air compressor package.
Add new section
6.10.6.2
Material selection philosophy shall be in accordance with the recommendations and guidelines of ISO 21457, unless explicitly specified in Table 4.
Add new section
6.10.6.3
Material selection for components and accessories shall be based on following minimum requirements specified in Table 4. Alternative materials per the vendor’s standard, if equivalent or superior than specified may be considered, subject to the purchaser’s approval.
Add new section
6.10.6.4
Material of construction for core compressor and gear components shall follow the vendor’s standard approved by the purchaser.
Add new section
6.10.6.5
Depending on service conditions, if specified in the data sheet, volutes shall be internally coated with a corrosion or erosion resistant coating.

 

 

Add new section heading
6.10.7 Coating
Add new section
6.10.7.1
Surface preparation, coating and coating activities shall, as a minimum, conform to the requirements of ISO 12944 (all parts) or alternative equivalent standard approved by the purchaser.
Add new section
6.10.7.2
For offshore applications, the requirements of ISO 12944-9 shall be applicable.
Add new section
6.10.7.3
Cast iron, carbon steel and low alloy steel external surfaces shall be coated.
Add new section
6.10.7.4
Bearings, seals, flange mating faces, instrument dials, instrument cases, cable trays and cables, shafts, polished or machined surfaces, control valve stems, nameplates and item tags shall not be coated. These items shall be protected from blasting and coating being applied to adjacent equipment.
Add new section
6.10.7.5
Stainless steel equipment items and piping shall be coated when:
a. operating at a temperature exceeding 60 °C (140 °F) in an offshore environment
b. insulated. Add new section heading 6.10.7.6 Coating Procedure Specification
Add new section
6.10.7.6.1
If specified in the data sheet, surface preparation and coating shall be in accordance with a qualified coating procedure specification, conforming to ISO 12944-8 or alternative equivalent standard, and following the recommendations of the coating manufacturer.
Add new section
6.10.7.6.2 The coating procedure specification proposed by the vendor shall describe complete coating related works to be performed, including surface preparation, coating application, qualification and inspection.