Pneumatic control and on/off valves for thermoelectric plants

Transcription

1 BASIC REQUIREMENTS FOR QUALIFYING SUPPLY AND CONTRACTING COMPANIES Equipment category : FMVA11 Pneumatic control and on/off valves for thermoelectric plants Technical characteristics Page 1 of 8

2 CONTENTS 1. Introduction Description of the Product Classification Main Technical Characteristics Basic Requirements For Qualification... 6 Page 2 of 8

3 1. Introduction The present document concisely describes the characteristics of the Pneumatic control and on/off valves for thermoelectric plants product classification and defines the basic technical-qualitative requirements which the potential vendors should have in order to be enrolled in the Registry of Enel Qualified Suppliers. The qualification which will be awarded shall refer to the individual manufacturing facilities being evaluated and shall not be extended to the other manufacturing facilities of the company or of the industrial group to which the company, which are different from those being evaluated. The qualification may be awarded for the supply of all of the products belonging to the product qualification, described here below, or also for a part of the same. The valves which are the subject of the typology shall be used in thermoelectric power plants. The characteristics and the applicable norms of the engagement shall be stated in greater detail in the Technical Specifications which ENEL will supply for each engagement. Owing to the different kinds of typologies for power plants, the functional and manufacturing requirements described below are stated as an example; they also take into account both the general requirements as well as those specific ones for the engagement in question. 2. Description of the Product Classification The product classification under examination is subdivided into two subgroups (A and B), for which a differentiated qualification is foreseen: SUBGROUP A: Turbine by-pass valves and those of a similar nature together with the related steam desuperheating systems The valves are understood to be complete with: - Pneumatic or hydraulic actuators; - accessories such as an intelligent positioners, feed back position transmitter, limit switches, solenoid valves, manual override, instrument air reserve tanks; - hydraulic control unit (eventual) complete with an interface with the main regulating system. The desuperheating system is understood to be complete with: - pneumatic and hydraulic steam temperature regulating valves, equipped with all of the necessary accessories; - System of desuperheating water spray and injection nozzles (desuperheating station). (Such systems can eventually be incorporated in the temperature regulating valves assuming the configuration of the variable desuperheater nozzle ) SUBGROUP B: Various regulating control and pneumatic on/off valves The section includes regulating control and pneumatic on/off valves, complete with accessories. The process fluids are normally undercooled liquids (with problems of cavitation), saturated or evaporating liquids (with problems of flashing), saturated and superheated steam, liquid and gas fuels as well as auxiliary fluids in general. The operational conditions can involve elevated differential pressures and high temperatures. The circuits concerned are consequently the following: - Condensate. - Feed water. - Main steam. - Hot reheat steam cold reheat steam. - Auxiliary steam. - Drainage and vents. Page 3 of 8

4 - Turbine bleeding. - Fuels (liquids and gaseous). - Auxiliary services. The engagements concern both the sections in which the product typology under examination has been divided and include the following services which will be furnished: - Functional drawings, as well as executive and detailed planning of what is included in the supply. - Planning and control of the engineering and/or manufacturing activities, in particular, the correct application of manufacturing technologies (procedures, personnel, and means) contained in the fabrication project should be demonstrated, with special care given to those with a high technological content. - A quality control plan which shall be presented for acceptance; - Testing and controls carried out in the facility. - Marking, painting, storage, conditioning, preservation, transport. - Certification documentation. - Post-sales assistance. In addition the suppliers should furnish information concerning the planning and state of progress of the individual engineering and manufacturing activities in conformity with the procedures set out by ENEL, on the occasion of each individual supply. 3. Main Technical Characteristics The equipment is to be designed for a conventional lifespan of 25 years. The vendor shall ensure a high degree of continuity in service and the maintenance shall be easy and reduced to a minimum. More detailed technical characteristics and requirements with which the vendor must comply are set out in the Technical Specification and Data Sheets furnished by ENEL for the individual supply. The more general and basic functional and fabrication characteristics are as follows: 3.1 Functional Features For the various functional aspects what is summarily meant to apply to both sections (except where they are indicated differently): a. Flow coefficient (Cv or Kv): should comply with the IEC norm, sections 1 to 5. The valve s effective discharge capacity can not deviate more than 5% from the value declared by the Manufacturer. b. Noise level: at 1 meter of distance from the valve, the equivalent continuous A LAeq-weighted Sound Pressure Levels measured and corrected in compliance with the ISO 1996, should not exceed the limits indicated in the procurement technical specifications (normally the required values are between 82 and 85 dba with a tolerance of + 0 db), throughout the operating range of the valve. c. Cavitation and lamination: with incompressible fluids and in the presence of high pressure differentials, the design shall provide a sufficient number of discrete pressure drop stages, to keep the fluid velocity and pressure recovery to a degree where cavitating, flashing and/or lamination erosion phenomena are prevented. Control valves on critical services, as Turbine by-pass, desuperheating and feed Page 4 of 8

5 water pump recirculating, shall have multistage or labyrinth trim. Proper numbers of pressure reduction steps shall limit the outlet fluid velocity within 23 m/s, overall operating conditions. d. Stroking speed: should normally between 5 mm/s and 10 mm/s. For the valves of section A is required that the valves stroke over their entire travel in less than 3 s. e. Leakage Class as well as functional tests should be performed in compliance with the Standard IEC , Class V. f. Characteristic curve and rangeability: for the related formulation criteria and acceptability please refer to the IEC Standard g. On-Off valves can be exceptionally equipped by electrical actuators. In that cases the motor control shall be incorporated on-board. 3.2 Construction Characteristics The valve bodies should be cast or forged in a single piece and can be globe-style, rotary, angle-style or Z -style, with flanged or weld end connections. Flangless or wafter-type bodies are acceptable for ratings which are less than PN50. Compound, split body or welded valve bodies are not acceptable. The sizing of the bodies and pressure parts must be in conformity with the ANSI B16-34 and DIN 3840 design standards. The entire unit actuator valve and accessories, as concerns the design, manufacturing and evaluation of conformity must comply with the directive PED n 97/23/CE, incorporated into the Legislative Decree n 93 of 25 February The body materials will be chosen, not only in function of the design sheets also of the kind of thermodynamic transformation of the process fluid. In particular, for pressure reducing valves operating with liquids with high pressure differentials or with vaporizing liquids, bodies in Cr-Mo alloy (ASTM A217-WC9, A217- WC6, A217-C5) must be chosen. Normally the trim will be of a cage-style (single or multiple), with quick-change type trim and with a balanced plug, with or without pilot balancing. 3.3 Testing and performance guarantee Each valve, complete with actuator and accessories will undergo the following tests, in accordance with details stated in ENEL s technical specifications: Shop Testing: - Standard tests; hydraulic pressure test of the valve bodies, the seal plug-seat, magnetic particle testing, liquid penetrant testing, radiographic testing; - Functional tests such as the verification of nominal stroke, deadband test and stroke times; - Special tests, upon requests on the data sheets, radiographic and ultrasound examinations On site Tests: Checks on the noise level produced by the valves, on load stroke times and on flow capacity if necessary are foreseen. Page 5 of 8

6 They should furthermore be supplied with a certificate from the manufacturer stating all of the chemical-mechanical characteristics of the pressure components together with those of the actuation system. The certification concerning the tests, controls and materials must state the values encountered during the testing and their evaluation, the method utilized, the reference standards and procedures used. 3.4 Reference Standards The basic reference Standards are the following: - ANSI ASME B Complete series of the IEC PED directive, 97/23/EC and the Legislative Decree of adoption n 93 of 25 February EN Standards - Gost Standard 4. Basic Requirements For Qualification The basic technical-qualitative requirements necessary for inclusion in the list of Enel suppliers for the valve type in question are indicated below: CASE A: MANUFACTURERS - Conformity of designs offered and completed with the functional and structural requirements requested by Enel. - References as a supplier of valves of the same type, manufactured and in operation; in the event of supply under license, in addition to the references of licensors, licensees must prove they possess references for the manufacture and supply of similar products in terms of size and complexity which are already in operation; licensing agreements must also guarantee an adequate duration and degree of involvement on the part of the licensor in the transfer of know-how to the licensee and in post-sales assistance. - For supply under license the verification of the design, where required, is performed directly by the licensor (at least for parts covered by the license and/or those requiring new features as compared with already completed machinery). - Design departments equipped with staff and IT capabilities of a level able to ensure the implementation of the required activities. - In the event of supply under license, once the suitability of the licensor has been confirmed, the manufacturer must demonstrate access to design facilities with adequate know-how for developing the specifications and structural design as well as manufacturing plans. - A management structure able to guarantee the coordination and planning of design and manufacturing activities, as required by ENEL management procedures. - Adequate resources for manufacturing activities. In this respect, the availability of special processing equipment and adequately qualified personnel is essential. Page 6 of 8

7 - Third parties may be employed in the manufacturing of parts, components, semi-finished products, etc., provided the supplier demonstrates the ability, based on the recorded capacities, to adequately control and supervise the tasks assigned to the third parties and that these possess the relative requirements. - An adequate post-sales assistance service able to ensure: The supply of spare parts interchangeable with those initially supplied, including any updates completed by the responsible personnel. Adequate resources for ordinary maintenance activities and for the modification of valve components (seals, power actuators, etc.). - Valves supplied for plants within the European community should be PED certified and possess the relative CE mark. - The company must have the ISO 9001 certification issued by an accredited entity, in compliance to the industry sector for the type of group qualification, it will constitute sufficient proof of the adequacy of the QMS itself. ENEL reserves, however, also in this case, the right to perform a verification of SQ, as it deems necessary. - Availability to supply, at the time of ordering, the following minimum documentation: o the drawings of the whole valve and its main components containing sizes, weights, materials together with the operating conditions and the parts list of components; o list of the components and recommended spare parts; o manual of instructions for the installation, running and maintenance, including the instructions of the accessory components in the Italian language; o technical manufacturing dossier of each valve containing all the control certificates and tests carried out (certified materials, Non Destructive Testing report, certificate of the hydraulic testing etc.). - Availability to allow the inspection, during qualification, of the construction designs of the valves; such designs should be the same used during the manufacturing of the valves for sizing controls, for the correct execution of the surface finish, etc. CASE B: DISTRIBUTORS - Distributors must define, during the qualification process, for which manufacturers and factories they want to be qualified. In this way, their qualification will be limited to those specific manufacturers and factories and will not be allowed to provide any product from other manufacturers or factories. - The distributors will request to manufacturers to qualify themselves in the ENEL supplier qualification system (CASE A). In case the manufacturer does not agree to qualify directly in the ENEL supplier qualification system, the distributor must demostrate the compliance of manufacturer s factories. In this case, the distributor have to collect all manufacturer documentation required for the qualification and organize, in agreement with ENEL personnel, manufacturer s factories survey. During this survey, additional Page 7 of 8

8 documentation will be required. The final conformity of manufacturer and its factories is subject to the ENEL approval. - In both cases, it will be required a document signed by both parties (distributor and manufacturer) that ensures the relationship between them and the technical support from the manufacturer whenever required by Enel Group. - For each manufacturer s factory, the distributor must demonstrate that one of the following points is applicable: h. The manufacturer is established in the European Community i. The manufacturer appointed an authorised representative in the European Community (The delegation of tasks from the manufacturer to the authorised representative must be explicit and should take place in writing) j. Distributor is the importer (company responsible for placing on the European Community market). Distributor must show the formal assurance in writing from the manufacturer that the documents required by PED (97/23/EC) will be made available when requested by the surveillance authority. k. The valves will not be supplied for plants in the European Community. - References as a supplier of valves of the same type and manufacturer and in operation: The supplier will have a total turnover over the last 3 years by at least Euro ,00 (nine million euros). The turnover on valves over the last 3 years should be at least Euro ,00 (six million euros). List of references showing the supply of products of the type under consideration, or equivalent, for the last three years, stating the quantities, customer and date of acquisition. - Declaration of having a structure of deliveries that ensures, generally, the delivery of the ordered material in the whole national territory within 10 working days from the date of order. - An adequate post-sales assistance service able to ensure: The supply of spare parts interchangeable with those initially supplied, including any updates completed by the responsible personnel. Adequate resources for ordinary maintenance activities and for the modification of valve components (capacity, power actuators, etc.). - Valves supplied for plants within the European community shall be PED certified and possess the relative CE mark. - The company must have the ISO 9001 certification issued by an accredited entity, in compliance to the industry sector for the type of group qualification, it will constitute sufficient proof of the adequacy of the QMS itself. ENEL reserves, however, also in this case, the right to perform a verification of SQ, as it deems necessary. Page 8 of 8