I. Overview Pipeline transportation has become the main mode of energy transport in the contemporary era. Utilizing long-distance pipelines to transport resources such as oil, gas and coal has become the most important means of solving energy transmission in the world today. The major oil and gas producing and consuming countries in the world have made extensive use of long-distance pipelines to solve the transportation problems of oil and gas resources. Over 95% of natural gas is transported by pipeline. According to statistics, the total length of long-distance oil and gas transmission pipelines in the world has exceeded 2.6 million kilometers, of which, the total length of natural gas transmission pipelines is about 1.4 million kilometers, accounting for more than one half of the total length. From the experience of construction and operation abroad, it is more economical to build a large diameter pipe than to build several small diameter pipelines under the same conveying capacity. In addition, increasing the medium conveying pressure within a certain range can also increase the benefits. Abroad, the pipe length of pipelines with long pipelines larger than 1 meter in diameter accounts for about 80% of the total length. The maximum diameter of 1420 mm, the maximum pressure of 11.8 MPa. Long-distance pipeline at the starting point, the intermediate booster station, the trunk and the system at the entrance and exit, etc. to be set on and off and control of the valve. Due to various disasters and accidents, long-distance oil and gas pipelines may cause faults, oil and gas leakage, fire and explosion problems. For pipelines with long-distance pipelines with a distance of 20-30 km, a Emergency shut-off valve, electric valve or pneumatic valve. Visible a long-distance pipeline will use a lot of valves. Long-distance pipeline through the desert, rainforest swamps, mountains, plains, the region through the harsh climate, poor environmental conditions, the valve requirements higher than the common valve, pipeline valves to have a higher strength and better sealing performance, and more High life, fast and light operation, easy maintenance. The foreign pipelines have started early and developed rapidly. China still does not have a large-caliber long-distance pipeline and the construction of large-caliber long-distance pipelines is in its infancy. Therefore, it is necessary to conscientiously do a good job in standard setting of product specifications, product performance testing, etc. . Second, the long-distance pipeline valve Overview The use of long-distance pipeline transportation needs to control the flow of media, which requires a lot of valves in the pipeline. Long-distance pipeline valves, there are two main purposes: ①in the main entrance and exit of the system, the opening and closing cut off and the role of safety and security; ② starting point in the pipeline and the intermediate booster station, the role of control of medium transport . Foreign, long-distance pipeline on the selected amount of the largest number of valves are: flat gate valve, ball valve, emergency cut-off ball valve, check valve, quick ball valve. Valve connection form: flange connection and butt welding two. Valve drive are: manual, electric, pneumatic, hydraulic, electro-hydraulic linkage, gas-liquid linkage and other forms of drive. Abroad, the long-distance pipeline valve mainly performs API 6D standard of the American Petroleum Institute and complies with the corresponding product standards. (A) from the long-term pipeline development trend of the valve point of view, the pipeline valve requires the following features and functions: ⑴ valve with good sealing performance (to adapt to a variety of media and changing conditions); ⑵ with good fire performance Valve; ⑶ compact structure, small size, and has corrosion resistance and wear-resistant valve; ⑷ for long-distance pipeline large diameter valves and LNG delivery of high pressure and low temperature valve; ⑸ easy to pigging and has a good Anti-stress structure; ⑹ a high degree of mechanical and electrical integration of the valve. (B) a variety of pipeline valve structure features and functions of a flat gate valve plate gate valve main features are: shorter structural length, good sealing performance, smaller operating torque and opening and closing operating force is closer, the flow resistance is small, the valve need not be set Abnormally increased pressure device, with a gate valve with a guide through the cleaner to clean the pipeline. However, the height of the valve structure is high, about 3 to 4 times the pipe diameter. 2 ball valve ball valve main features are: compact structure, good sealing performance, opening and closing 90 ° rotation can quickly open and close the valve, the operating time is short, the use of sealing grease can form a secondary auxiliary seal, the seat of the fire structure in case of fire To ensure that the valve seal, supporting fast-cut device can achieve emergency valve opening and closing. 3 ball valve spherical control valve flow, simple structure, good stability, easy operation and maintenance, full flow resistance is small, allowing the use of large pressure drop, small noise, good cavitation resistance. 4 check valve Check valve with more damping structure, which can effectively eliminate the vibration of the pipeline and reduce the flow resistance; The double seal (low pressure with flexible seal, high pressure with metal - metal seal), sealing effect; through the pipe cleaner. 5 pressure relief valve due to open the pump or stop the pump may cause changes in the medium flow velocity and pressure fluctuations in the pipeline, resulting in shock wave. In order to eliminate the impact of shock waves, the use of pressure relief valve on long-distance pipeline to reduce shock wave. 6 Pressure Reducing Valve The pressure reducing valve is set on the branch pipeline to keep the medium pressure on the inlet side of the user constant. The pilot pressure reducing valve is more used. It has less influence on the cleanliness of the medium, higher pressure control precision and stable performance. (C) the long-distance pipeline valve materials used Long-distance pipeline valve selection should meet the strength, sealing, service life, high temperature, high pressure, wear, corrosion, fire, anti-static and other requirements from the foreign pipeline valve materials Look, the main selection of the following materials: The valve housing (body, bonnet) WCB, WCC, stainless steel plate valve gate stainless steel (surface treatment) ball valve ball stainless steel seat ring reinforced Teflon Valve stem Stainless steel gasket Stainless steel graphite or PTFE winding pad Connecting bolts High-quality alloy steel (IV) Long-distance pipeline to valve performance test requirements Long-distance pipeline affected by geographical conditions and natural conditions, subject to changes in climate temperature, topography and earthquakes And so on. Therefore, the long-distance pipeline valve inspection and testing more stringent, to the shell strength pressure test, sealing test, the performance test, bending test, tensile test, fire test, durability test, and some valves should Do cold and heat test. Test valve should be good sealing performance, flexible operation, accurate action, durability, for the delivery of a granular medium valve wear resistance test should be done. Third, an overview of the relevant domestic and international standards 1 foreign standards At present, the long-term pipeline valves mainly use the American Petroleum Institute standards API 6D "pipeline valve norms" and the corresponding product standards, such as: API 594 "Wafer Check Valve" API 599 "Steel and Ductile Iron Plug Valves", API 600 "Flanged or Butt Welded Steel Gate Valves for Refineries", API 607 ​​"Fire Tests for Soft-Seal Ball Valves", API 608 "Flanges and Butt Weld End Metal Ball Valve ", API 6FA" Valve Fire Test Specification ", BS 4460" Steel Ball Valve for Oil Industry "and so on. API 6D "Pipeline Valve Code" standard is a standard for the comprehensive requirements of pipeline valve manufacture, inspection, procurement, etc., other product standards, application scope, connection type, structure length, performance requirements, inspection and test, signs and so on Make detailed requirements. API 6D "Code for Pipeline Valves": Scope, General Provisions, Materials, Types and Categories of Valves, Tests, Markings, Requirements for Quality Control, Storage and Shipping, Appendix (Procurement Guidelines, Metric Conversion, Supplementary Testing Requirements, Reference Specifications And standard) nine chapters. 2 part of the domestic standard The existing domestic long-distance pipeline valve standards are: JB / T 5298-1991 "pipeline steel plate gate valve", JB / T 7745-1995 "pipeline ball valve", other long-distance pipeline products using common valve Product standards, some special valves (emergency shut-off valve, etc.) no national or industry standards. There is no standard specification for pipeline valves. Compared with foreign standards, existing domestic industry standards are simpler in content, less in content and less demanding. Fourth, the standard content analysis API 6D "pipeline valve Code" on the pipeline with valves (gate valve, plug valve, ball valve and check valve) order, design, manufacture, test and inspection, marking, etc. made a more detailed provisions, the specific content : 1 The valve diameter specifies the full-diameter valve, reducing valve and non-circular hole valve logo, which is conducive to the selection and application of valves; full-diameter valve channel diameter deviation is also clearly defined. 2 General There are valve pressure rating, rating, structure length, connection type and size, the requirements of special structures and so on. Specifies the valve pressure rating, rating (valve housing material according to ANSI B16.5 standard rating, the standard flange end and the standard welding end of the maximum allowable working pressure valve rating), diameter representation (full diameter Valve, reducing valve, non-circular hole reducing valve), structural length, end flange, welded end, design control, design qualification, design documents, relief, vent and bypass connections, , Position indicator. The length of the structure provides: a. According to ANSI B16.5 ratings and pressure rating of the standard type (flange or butt welded valve structure length; b. One end of the welding, the other end of the flange length of the valve structure ;. c does not list the length of the structure or length of the structure does not comply with the two structural length of the valve and the label provides the connection type and size requirements: a. Each size series end flange type and standards should be met; b. The structure and standard requirements for soldered ports, the requirements for the inner diameter of ports, which prescribe the design procedures, design controls, qualification and design documents, specify the requirements for the particular structure: a. Set the pressure relief device setting and size requirements; b. Discharge and bypass connection type and connection pipe size requirements; c. Lengthened wrench structure and composition; d. Locking device settings and locking device should be fixed valve position; e. Position indicator setting and indication requirements . 3 parts of the valve material a. The provisions of the valve body, bonnet, cover plate, end flange and welding end of the material grades and materials should comply with the standard specifications; b. Bolt, ball, plug, disc, hand wheel, transmission, pipe plug, electric accessories, etc. Other parts of the material should be the implementation of the standards and norms e material requirements of the sulfide stress rupture parts f performance performance of alternative metal materials, composition of the limited and judgments. Welding requirements require that all pressure parts and pressure control parts And welding and welding repair requirements; performance test of welding parts and test items, etc. 4 Valve types and categories (requirements for gate valve, plug valve, closure of ball valve check valve, sealing structure and operating movement), a For the double gate valve and the gate valve gate plate type composition, gate valve stem auxiliary seal and seal seat provided for; b cock plug sealing the composition and type of rotation have made provisions; c ball valve seal deputy The composition and type of rotation has been made d; all kinds of check valve (swing-type, single-valve and double-disc clip-on) Do not (full-diameter valve minimum channel diameter and tolerances, the length of the valve structure.) 5 test valve pressure test, strength test and static pressure seal test items, test methods and test dwell time made clear. 6 The marking of the valve requires that the valve body and the nameplate be marked (manufacturer's name, trademark, pressure-level structure length mark, maximum permissible working pressure rating, body material, seal identification, nominal valve diameter , Part number, media flow, structure length, serial number, year of manufacture, valve function markings, etc. 7 Quality control requirements define the qualification of the measuring and testing equipment, quality control personnel, general requirements for quality control, specific products and components Quality control 8 Storage and dispatch The provisions of the valve paint, emissions, anti-corrosion, sealing surface protection requirements. 9 Appendix As part of the standard content, it plays a guiding role in purchasing and testing valves. Appendix A procurement guidelines require the valve data sheet, field tests, pressure relief, pigs and ball, fire test principle. Valve Data Sheet lists the valve ordering, performance specifications, conditions of use, connecting and sealing sub-structure types, operating mechanism type and wrench size, valve support, other special requirements (supplementary test, fire test structure, pressure relief, , By-pass connections, documents provided, third party certifications or procedures / tests, painting and coating, etc.). Appendix C supplementary test requirements, detailed description of the pressure above the ANSI B16.5 standard pressure test pressure and test results of the media requirements, seal test requirements, test pressure, test pressure holding duration and test methods, operation Torque test methods and requirements. Through the above analysis, we can see that the API 6D standard has great guiding significance for the order, design, manufacture, test and inspection of pipeline valves, identification and so on. China's long-distance pipeline valve standards system is being established and is working to develop the relevant product standards.
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