GasTurbine Engineering HandbookSecond Edition phần 3 pptx

//INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 4.3D ± 149 ± [141±177/37] 29.10.2001 3:57PM ASME, Performance Test Code on Overall Plant Performance, ASME PTC 46 1996 This code is written to establish the overall plant performance. Power plants, which produce secondary energy output such as cogeneration facilities are included within the scope of this code. For cogeneration facilities, there is no requirement for a minimum percentage of the facility output to be in the form of electricity; however, the guiding principles, measurement methods, and calculation procedures are predicated on electricity being the primary output. As a result, a test of a facility with a low proportion of electric output may not be capable of meeting the expected test uncertainties of this code. This code provides explicit procedures for the determination of power plant thermal performance and electrical output. Test results provide a measure of the performance of a power plant or thermal island at a specified cycle configur- ation, operating disposition and/or fixed power level, and at a unique set of base reference conditions. Test results can then be used as defined by a contract for the basis of determination of fulfillment of contract guarantees. Test results can also be used by a plant owner, for either comparison to a design number, or to trend performance changes over time of the overall plant. The results of a test conducted in accordance with this code will not provide a basis for comparing the thermoeconomic effectiveness of different plant design. Power plants are comprised of many equipment components. Test data required by this code may also provide limited performance information for some of this equipment; however, this code was not designed to facilitate simultaneous code level testing of individual equipment. ASME PTCs, which address testing of major power plant equipment provide a determination of the individual equipment isolated from the rest of the system. PTC 46 has been designed to determine the performance of the entire heat-cycle as an integrated system. Where the performance of individual equipment operat- ing within the constraints of their design-specified conditions are of interest, ASME PTCs developed for the testing of specific components should be used. Likewise, determining overall thermal performance by combining the results of ASME code tests conducted on each plant component is not an acceptable alternative to a PTC 46 test. ASME, Performance Test Code on Test Uncertainty: Instruments and Apparatus PTC 19.1 1988 This test code specifies procedures for evaluation of uncertainties in individual test measurements, arising from both random errors and system- atic errors, and for the propagation of random and systematic uncertainties Performance and Mechanical Standards 149 //INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 4.3D ± 150 ± [141±177/37] 29.10.2001 3:57PM into the uncertainty of a test results. The various statistical terms involved are defined. The end result of a measurement uncertainty analysis is to provide numerical estimates of systematic uncertainties, random uncertain- ties, and the combination of these into a total uncertainty with an approxi- mate confidence level. This is especially very important when computing guarantees in plant output and plant efficiency. ASME, Performance Test Code on Gas Turbines, ASME PTC 22 1997 The object of the code is to detail the test to determine the power output and thermal efficiency of the gas turbine when operating at the test condi- tions, and correcting these test results to standard or specified operating and control conditions. Procedures for conducting the test, calculating the results, and making the corrections are defined. The code provides for the testing of gas turbines supplied with gaseous or liquid fuels (or solid fuels converted to liquid or gas prior to entrance to the gas turbine). Test of gas turbines with water or steam injection for emission control and/or power augmentation are included. The tests can be applied to gas turbines in combined-cycle power plants or with other heat recovery systems. Meetings should be held with all parties concerned as to how the test will be conducted and an uncertainty analysis should be performed prior to the test. The overall test uncertainty will vary because of the differences in the scope of supply, fuel(s) used, and driven equipment characteristics. The code establishes a limit for the uncertainty of each measurement required; the overall uncertainty is then calculated in accordance with the procedures defined in the code and by ASME PTC 19.1. Mechanical Parameters Some of the best standards from a mechanical point of view have been written by the American Petroleum Institute (API) and the American Society of Mechanical Engineers, as part of their mechanical equipment standards. The ASME and the API mechanical equipment standards are an aid in specifying and selecting equipment for general petrochemical use. The intent of these specifications is to facilitate the development of high- quality equipment with a high degree of safety and standardization. The user's problems and experience in the field are considered in writing these specifications. The task force, which writes the specifications, consists of members from the user, the contractor, and the manufacturers. Thus, the task-force team brings together both experience and know-how. 150 Gas Turbine Engineering Handbook //INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 4.3D ± 151 ± [141±177/37] 29.10.2001 3:57PM The petroleum industry is one of the largest users of gas turbines as prime movers for drives of mechanical equipment and also for power generation equipment. Thus the specifications written are well suited for this industry, and the tips of operation and maintenance apply for all industries. This section deals with some of the applicable API and ASME standards for the gas turbine and other various associated pieces. It is not the intent here to detail the API or ASME standards, but to discuss some of the pertinent points of these standards and other available options. It is strongly recommended that the reader obtain from ASME and API all mechanical equipment standards. API Std 616, Gas Turbines for the Petroleum, Chemical, and Gas Industry Services, 4th Edition, August 1998 This standard covers the minimum requirements for open, simple, and regenerative-cycle combustion gas turbine units for services of mechanical drive, generator drive, or process gas generation. All auxiliary equipment required for starting and controlling gas turbine units, and for turbine protection is either discussed directly in this standard or referred to in this standard through references to other publications. Specifically, gas turbine units that are capable of continuous service firing gas or liquid fuel or both are covered by this standard. In conjunction with the API specifications the following ASME codes also supply significant data in the proper selection of the gas turbine. ASME Basic Gas Turbines B 133.2 Published: 1977 (Reaffirmed Year: 1997) This standard presents and describes features that are desirable for the user to specify in order to select a gas turbine that will yield satisfactory performance, availability, and reliability. The standard is limited to a con- sideration of the basic gas turbine including the compressor, combustion system, and turbine. ASME Gas Turbine Fuels B 133.7M Published: 1985 (Reaffirmed Year: 1992) Gas turbines may be designed to burn either gaseous or liquid fuels, or both with or without changeover while under load. This standard covers both types of fuel. Performance and Mechanical Standards 151 //INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 4.3D ± 152 ± [141±177/37] 29.10.2001 3:57PM ASME Gas Turbine Control and Protection Systems B133.4 Published: 1978 (Reaffirmed Year: 1997) The intent of this standard is to cover the normal requirements of the majority of applications, recognizing that economic trade-offs and reli- ability implications may differ in some applications. The user may desire to add, delete, or modify the requirements in this standard to meet his specific needs, and he has the option of doing so in his own bid specifica- tion. The gas turbine control system shall include sequencing, control, protection, and operator information, which shall provide for orderly and safe start-up of gas turbine, control of proper loading, and an orderly shutdown procedure. It shall include an emergency shutdown capability, which can be operated automatically by suitable failure detectors or which can be operated manually. Coordination between gas turbine con- trol and driven equipment must be provided for startup, operation, and shutdown. ASME Gas Turbine Installation Sound Emissions B133.8 Published: 1977 (Reaffirmed Year: 1989) This standard gives methods and procedures for specifying the sound emissions of gas turbine installations for industrial, pipeline, and utility applications. Included are practices for making field sound measurements and for reporting field data. This standard can be used by users and manu- facturers to write specifications for procurement, and to determine com- pliance with specification after installation. Information is included, for guidance, to determine expected community reaction to noise. ASME Measurement of Exhaust Emissions from Stationary Gas Turbine Engines B133.9 (Published: 1994) This standard provides guidance in the measurement of exhaust emissions for the emissions performance testing (source testing) of stationary gas turbines. Source testing is required to meet federal, state, and local environ- mental regulations. The standard is not intended for use in continuous emissions monitoring although many of the online measurement methods defined may be used in both applications. This standard applies to engines that operate on natural gas and liquid distillate fuels. Much of this standard also will apply to engines operated on special fuels such as alcohol, coal gas, residual oil, or process gas or liquid. However, these methods may require 152 Gas Turbine Engineering Handbook //INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 4.3D ± 153 ± [141±177/37] 29.10.2001 3:57PM modification or be supplemented to account for the measurement of exhaust components resulting from the use of a special fuel. ASME Procurement Standard for Gas Turbine Electrical Equipment B133.5 (Published: 1978) (Reaffirmed Year: 1997) The aim of this standard is to provide guidelines and criteria for specifying electrical equipment, other than controls, which may be supplied with a gas turbine. Much of the electrical equipment will apply only to larger generator drive installations, but where applicable this standard can be used for other gas turbine drives. Electrical equipment described here, in almost all cases, is covered by standards, guidelines, or recommended practices documented elsewhere. This standard is intended to supplement those references and point out the specific areas of interest for a gas turbine application. For a few of the individual items, no other standard is referenced for the entire subject, but where applicable a standard is referenced for a sub-item. A user is advised to employ this and other more detailed standards to improve his specification for a gas turbine installation. In addition, regulatory require- ments such as OSHA and local codes should be considered in completing the final specification. Gas turbine electrical equipment covered by this standard is divided into four major areas: Main Power System, Auxiliary Power System, Direct Current System, Relaying. The main power system includes all electrical equipment from the generator neutral grounding connection up to the main power transformer or bus but not including a main transformer or bus. The auxiliary power system is the gas turbine section AC supply and includes all equipment necessary to provide such station power as well as motors utilizing electrical power. The DC system includes the battery and charger only. Relaying is confined to electric system protective relaying that is used for protection of the gas turbine station itself. ASME Procurement Standard for Gas Turbine Auxiliary Equipment B133.3 (Published: 1981) (Reaffirmed Year: 1994) The purpose of this standard is to provide guidance to facilitate the preparation of gas turbine procurement specifications. It is intended for use with gas turbines for industrial, marine, and electric power applications. The standard also covers auxiliary systems such as lubrication, cooling, fuel (but not its control), atomizing, starting, heating-ventilating, fire protection, cleaning, inlet, exhaust, enclosures, couplings, gears, piping, mounting, painting, and water and steam injection. Performance and Mechanical Standards 153 //INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 4.3D ± 154 ± [141±177/37] 29.10.2001 3:57PM API Std 618, Reciprocating Compressors for Petroleum, Chemical, and Gas Industry Services, 4th Edition, June 1995 This standard could be adapted to the fuel compressor for the natural gas to be brought up to the injection pressure required for the gas turbine. Covers the minimum requirements for reciprocating compressors and their drivers used in petroleum, chemical, and gas industry services for handling process air or gas with either lubricated or nonlubricated cylinders. Compressors covered by this standard are of moderate-to-low speed and in critical services. The nonlubricated cylinder types of compressors are used for inject- ing fuel in gas turbines at the high pressure needed. Also covered are related lubricating systems, controls, instrumentation, intercoolers, after-coolers, pulsation suppression devices, and other auxiliary equipment. API Std 619, Rotary-Type Positive Displacement Compressors for Petroleum, Chemical, and Gas Industry Services, 3rd Edition, June 1997 The dry helical lobe rotary compressors nonlubricated cylinder types of compressors are used for injecting of the fuel in gas turbines at the high pressure needed. The gas turbine application requires that the compressor be dry. This standard is primarily intended for compressors that are in special purpose application and covers the minimum requirements for dry helical lobe rotary compressors used for vacuum, pressure, or both in petroleum, chemical, and gas industry services. This edition also includes a new inspector's checklist and new schematics for general purpose and typical oil systems. API Std 613 Special Purpose Gear Units for Petroleum, Chemical, and Gas Industry Services, 4th Edition, June 1995 Gears, wherever used, can be a major source of problem and downtime. This standard specifies the minimum requirements for special-purpose, enclosed, precision, single- and double-helical one- and two-stage speed increasers and reducers of parallel-shaft design for refinery services. Primar- ily intended for gears that are in continuous service without installed spare equipment. These standards apply for gears used in the power industry. API Std 677, General-Purpose Gear Units for Petroleum, Chemical, and Gas Industry Services, 2nd Edition, July 1997 (Reaffirmed March 2000) This standard covers the minimum requirements for general-purpose, enclosed single- and multi-stage gear units incorporating parallel-shaft 154 Gas Turbine Engineering Handbook //INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 4.3D ± 155 ± [141±177/37] 29.10.2001 3:57PM helical and right angle spiral bevel gears for the petroleum, chemical, and gas industries. Gears manufactured according to this standard are limited to the following pitchline velocities: helical gears shall not exceed 12,000 feet per minute 60 meters per second (60 meters per second) and spiral bevel gears shall not exceed 8,000 feet per minute 40 meters per second (40 meters per second). This standard includes related lubricating systems, instrumentation, and other auxiliary equipment. Also included in this edition is new material related to gear inspection. API Std 614, Lubrication, Shaft-Sealing, and Control-Oil Systems and Auxiliaries for Petroleum, Chemical, and Gas Industry Services, 4th Edition, April 1999 Lubrication, besides providing lubrication, also provides cooling for vari- ous components of the turbine. This standard covers the minimum require- ments for lubrication systems, oil-type shaft-sealing systems, and control-oil systems for special-purpose applications. Such systems may serve compres- sors, gears, pumps, and drivers. The standard includes the systems' com- ponents, along with the required controls and instrumentation. Data sheets and typical schematics of both system components and complete systems are also provided. Chapters include general requirements, special purpose oil systems, general purpose oil systems and dry gas seal module systems. This standard is well written and the tips detailed are good practices for all types of systems. API Std 671, Special Purpose Couplings for Petroleum Chemical and Gas Industry Services, 3rd Edition, October 1998 This standard covers the minimum requirements for special purpose couplings intended to transmit power between the rotating shafts of two pieces of refinery equipment. These couplings are designed to accommodate parallel offset, angular misalignment, and axial displacement of the shafts without imposing excessive mechanical loading on the coupled equipment. ANSI/API Std 670 Vibration, Axial-Position, and Bearing-Temperature Monitoring Systems, 3rd Edition, November 1993 Provides a purchase specification to facilitate the manufacture, procure- ment, installation, and testing of vibration, axial position, and bearing temperature monitoring systems for petroleum, chemical, and gas industry services. Covers the minimum requirements for monitoring radial shaft Performance and Mechanical Standards 155 //INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 4.3D ± 156 ± [141±177/37] 29.10.2001 3:57PM vibration, casing vibration, shaft axial position, and bearing temperatures. It outlines a standardized monitoring system and covers requirements for hardware (sensors and instruments), installation, testing, and arrangement. Standard 678 has been incorporated into this edition of standard 670. This is well-documented, standard, and widely used in all industries. Application of the Mechanical Standards to the Gas Turbine An examination of the above standards as they apply to the gas turbine and its auxiliaries are further examined in this section. The ASME B 133.2 basic gas turbines and the API standard 616, gas turbines for the petroleum, chemical, and gas industry services are intended to cover the minimum specifications necessary to maintain a high degree of reliability in an open- cycle gas turbine for mechanical drive, generator drive, or hot-gas genera- tion. The standard also covers the necessary auxiliary requirements directly or indirectly by referring to other listed standards. The standards define terms used in the industry and describe the basic design of the unit. It deals with the casing, rotors and shafts, wheels and blades, combustors, seals, bearings, critical speeds, pipe connections and auxiliary piping, mounting plates, weather-proofing, and acoustical treat- ment. The specifications call preferably for a two-bearing construction. Two- bearing construction is desirable in single-shaft units, as a three-bearing configuration can cause considerable trouble, especially when the center bearing in the hot zone develops alignment problems. The preferable casing is a horizontally split unit with easy visual access to the compressor and turbine, permitting field balancing planes without removal of the major casing components. The stationary blades should be easily removable with- out removing the rotor. A requirement of the standards is that the fundamental natural frequency of the blade should be at least two times the maximum continuous speed, and at least 10% away from the passing frequencies of any stationary parts. Experience has shown that the natural frequency should be at least four times the maximum continuous speed. Care should be exercised on units where there is a great change in the number of blades between stages. A controversial requirement of the specifications is that rotating blades or labyrinths for shrouded rotating blades be designed for slight rubbing. A slight rubbing of the labyrinths is usually acceptable, but excessive rubbing can lead to major problems. New gas turbines use ``squealer blades'' some manufacturers suggest using ceramic tips, but whatever is done, great care should be exercised, or blade failure and housing damage may occur. 156 Gas Turbine Engineering Handbook //INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 4.3D ± 157 ± [141±177/37] 29.10.2001 3:57PM Labyrinth seals should be used at all external points, and sealing pressures should be kept close to atmospheric. The bearings can be either rolling element bearings usually used in aero-derivative gas turbines and hydro- dynamic bearings used in the heavier frame type gas turbines. In the area of hydrodynamics bearings, tilting pad bearings are recommended, since they are less susceptible to oil whirl and can better handle misalignment problems. Critical speeds of a turbine operating below its first critical should be at least 20% above the operating speed range. The term commonly used for units operating below their first critical is that the unit has a ``stiff shaft,'' while units operating above their first critical are said to have a ``flexible shaft.'' There are many exciting frequencies that need to be considered in a turbine. Some of the sources that provide excitation in a turbine system are: 1. Rotor unbalance 2. Whirling mechanisms such as: a. Oil whirl b. Coulomb whirl c. Aerodynamic cross coupling whirl d. Hydrodynamic whirl e. Hysteretic whirl 3. Blade and vane passing frequencies 4. Gear mesh frequencies 5. Misalignment 6. Flow separation in boundary layer exciting blades 7. Ball/race frequencies in antifriction bearings usually used in aero- derivative gas turbines Torsional criticals should be at least 10% away from the first or second harmonics of the rotating frequency. Torsional excitations can be excited by some of the following: 1. Start up conditions such as speed detents 2. Gear problems such as unbalance and pitch line runout 3. Fuel pulsation especially in low NO x combustors The maximum unbalance is not to exceed 2.0 mils (0.051 mm) on rotors with speeds below 4000 rpm, 1.5 mils (0.04 mm) for speeds between 4000  ± 8000 rpm, 1.0 mil (0.0254 mm) for speeds between 8000  ±12,000 rpm, and 0.5 mils (0.0127 mm) for speeds above 12,000 rpm. These requirements are to Performance and Mechanical Standards 157 //INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 4.3D ± 158 ± [141±177/37] 29.10.2001 3:57PM be met in any plane and also include shaft runout. The following relationship is specified by the API standard: L v   12000 N r 4-1 where: L v  Vibration Limit mils (thousandth of an inch), or mm (mils  25:4 N  Operating speed (RPM) The maximum unbalance per plane (journal) shall be given by the follow- ing relationships: U max  4W=N 4-2 where: U max  Residual unbalance ounce-inches (gram-millimeters) W  Journal static weight Lbs (kg) A computation of the force on the bearings should be calculated to determine whether or not the maximum unbalance is an excessive force. The concept of an Amplification Factor (AF) is introduced in the new API 616 standard. Amplification factor is defined as the ratio of the critical speed to the speed change at the root mean square of the critical amplitudes. AF  N c1 N 2 À N 1  4-3 Figure 4-6 is an amplitude-speed curve showing the location of the run- ning speed to the critical speed, and the amplitude increase near the critical speed. When the rotor amplification factor, as measured at the vibration probe, is greater than or equal to 2.5, that frequency is called critical and the corresponding shaft rotational frequency is called a critical speed. For the purposes of this standard, a critically damped system is one in which the amplification factor is less than 2.5. Balancing requirement in the specifications require that the rotor with blades assembled must be dynamically balanced without the coupling, but 158 Gas Turbine Engineering Handbook [...]... Turbines B 133 .2 Published: 1977 (Reaffirmed year: 1997) ASME Gas Turbine Control and Protection Systems B 133 .4 Published: 1978 (Reaffirmed year: 1997) ASME Gas Turbine Installation Sound Emissions B 133 .8 Published: 1977 (Reaffirmed: 1989) ASME Measurement of Exhaust Emissions from Stationary Gas Turbine Engines B 133 .9 Published: 1994 ASME Procurement Standard for Gas Turbine Electrical Equipment B 133 .5 Published:... (26-10-01)/CHAPTER 4.3D ± 1 73 ± [141±177 /37 ] 29.10.2001 3: 57PM Performance and Mechanical Standards 1 73 Table 4-2 continued 27 28 29 30 Exhaust diffuser Performance map of turbine and compressor Gearing Drawings Accessories 1 2 3 4 5 Lubrication systems Intercoolers Inlet filtration system Control system Protection system Table 4 -3 Vendor Requirements to be Provided by the User for a Compressor Train 1 2 3 4 5 6... //INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 4.3D ± 177 ± [141±177 /37 ] 29.10.2001 3: 57PM Performance and Mechanical Standards 177 API Std 619, Rotary-Type Positive Displacement Compressors for Petroleum, Chemical, and Gas Industry Services, 3rd Edition, June 1997 API Publication 534 , Heat Recovery Steam Generators, 1st Edition, January 1995 API RP 556, Fired Heaters & Steam Generators, 1st Edition, May 1997 API Std 671,... (Reaffirmed year: 1997) ASME Procurement Standard for Gas Turbine Auxiliary Equipment B 133 .3 Published: 1981 (Reaffirmed year: 1994) ISO 10 436 :19 93 Petroleum and Natural Gas IndustriesÐGeneral purpose Steam Turbine for Refinery Service, 1st Edition //INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 5.3D ± 178 ± [178±218/41] 29.10.2001 3: 57PM 5 Rotor Dynamics The present trend in rotating equipment is toward increasing... Gas Industry Services, 8th Edition, August 1995 ANSI/API Std 670 Vibration, Axial-Position, and Bearing-Temperature Monitoring Systems, 3rd Edition, November 19 93 API Std 611, General Purpose Steam Turbines for Petroleum, Chemical, and Gas Industry Services, 4th Edition, June 1997 API Std 6 13 Special Purpose Gear Units for Petroleum, Chemical, and Gas Industry Services, 4th Edition, June 1995 API Std... mils (2. 032 mm) For the axial position, the channel linearity must be Æ5% of 200 millivolts per mil sensitivity and a Æ1:0 mil of a straight line over a minimum operating range of 80 mils (2. 032 mm) Temperature should not affect the linerarity of the system by more than 5% over a temperature range of 30 to 35 0 8F ( 34 :4 to ‡176:7 8C) for the //INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 4.3D ± 169 ±... Industry Services, 3rd Edition, October 1998 API Std 672, Packaged, Integrally Geared Centrifugal Air Compressors for Petroleum, Chemical, and Gas Industry Services, 3rd Edition, September 1996 API Std 677, General-Purpose Gear Units for Petroleum, Chemical, and Gas Industry Services, 2nd Edition, July 1997, Reaffirmed March 2000 API Std 681, Liquid Ring Vacuum Pumps and Compressors, 1st Edition, February... Condensing Apparatus, ASME PTC 12.2 19 83, American Society of Mechanical Engineers 19 83 ASME, Performance Test Code on Atmospheric Water Cooling Equipment PTC 23, 1997 ASME Gas Turbine Fuels B 133 .7M Published: 1985 (Reaffirmed year: 1992) ISO, Natural GasÐCalculation of Calorific Value, Density and Relative Density International Organization for Standardization ISO 6976-19 83( E) Table of Physical Constants... diameters should be 0.190±0.195 inches (4.8± 4.95 mm) with body diameters of 1/4 (6 .35 mm)  ±28 UNF À2A threaded, or   0 .3 0 .31 2 inches (7.62±7.92 mm) with a body diameter of 3/ 8 (9.52 mm) À24 UNF ±24A threaded The probe length is about 1 inch long Tests   conducted on various manufacturer's probes indicate that the 0 .3 0 .31 2-inch  (7.62±7.92 mm) probe has a better linearity in most cases The integral... temperature, relative humidity, MW, etc State expected variation in discharge pressure table continued on next page //INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 4.3D ± 174 ± [141±177 /37 ] 29.10.2001 3: 57PM 174 Gas Turbine Engineering Handbook Table 4 -3 continued 7 8 9 10 11 12 It is extremely important that changing conditions be related to each other If relative humidity varies from 50 to 100% and inlet . 151 //INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 4.3D ± 152 ± [141±177 /37 ] 29.10.2001 3: 57PM ASME Gas Turbine Control and Protection Systems B 133 .4 Published: 1978 (Reaffirmed Year: 1997) The intent. However, these methods may require 152 Gas Turbine Engineering Handbook //INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 4.3D ± 1 53 ± [141±177 /37 ] 29.10.2001 3: 57PM modification or be supplemented to account. 1 53 //INTEGRA/B&H/GTE/FINAL (26-10-01)/CHAPTER 4.3D ± 154 ± [141±177 /37 ] 29.10.2001 3: 57PM API Std 618, Reciprocating Compressors for Petroleum, Chemical, and Gas Industry Services, 4th Edition,