Standard Duty SLN - Temp Desuperheater Model: 50 / 60

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1 Narvik-Yarway covers requirements for Desuperheaters, pneumatic actuators, strainers with a wide range of models, sizes and materials to satisfy all the specifications of the power-pulp & paper industry and process gas applications. Features Fabricated construction Spring loaded nozzle type Wide range of Cv (Kv) capacities available Special nozzle combinations available Pressure class and connections: - ASME/ ANSI B16.34 class 150 to DIN 2401 class PN 25 to Buttweld connections to ASME B16.25 or DIN 2559 Materials: - ASTM SA 105 / SA 106 Gr.B or DIN C22.8 / St III - ASTM SA 182 F11 / SA 335 P11 or DIN Other materials upon request Technical data Size : Steam 3 (DN 80) Water 1-1 1/2 (DN 25-40) Steam 4 (DN 100) Water 1 1/ (DN ) General application Cooling of process steam or gas, Boiler superheater, Boiler reheater, Turbine bleed steam and Pressure reducing valve Tyco reserves the right to change the content without notice NRVSB-0091-EN-0911

2 Standard Duty SLN - Temp Desuperheater Water inlet flange is available to various standards. Model 50: 1-1 1/2 (DN 25-40) Model 60: 1 1/ (DN ) Version circular-welded for class 600 (PN 100) up to and including class 1500 (PN 250). Steam flange is available to various standards. Model 50: 3 (DN 80) Model 60: 4 (DN 100) Version tack-welded for class 150 (PN 25/40) and class 300 (PN 64) Tackweld Tackweld Fabricated body available in various materials. Construction in accordance with ASME B / TRD 110. CE-marking, if required. Body extension pipe in various lengths, depending upon the installation requirements. Spring loaded spray nozzles give fine atomization of injection water. Fig. 1 Fig. 2 Tyco reserves the right to change the content without notice page 2

3 The Narvik-Yarway SLN - Temp Desuperheater is specifically developed for use on low-/medium pressure steam applications. The fluid to be injected is fed to the individual nozzles through tangentially positioned drillings. This results in fluid rotation within the nozzle chamber. At the momentum the valve disc opens the fluid will form a fine hollow cone. Hollow cone atomizers have been proven to be the best for desuperheating applications. The fabricated construction makes it easy adaptable to meet various boiler codes and material specifications. The unit can also be used as a liquid into gas injector for which high grade alloy such as stainless Steel or high nickel alloys are often used. The nozzle components are selected from high grade alloy steels. They are attached by seal welds and no threading is applied to the nozzle housing. The spring loaded nozzles are selected such that the opening is sequentially. This is assures that in all load situations the number of nozzles in service is optimal. Spring ranges and the number of nozzles will be selected in function of this sequential opening/closing, depending upon data supplied by the customer. This allows for tailor made solutions. The SLN-Temp requires a separate water control valve to regulate the quantity of injection water. Narvik-Yarway will specify the data to size this valve. Upon customer request this component can also be included in the Narvik-Yarway supply. Applications Narvik-Yarway SLN - Temp Desuperheaters are used for temperature control of: turbine bleed steam - pressure reducing valve outlet steam - process steam and process gasses. Superior spray nozzle Narvik-Yarway has incorporated the latest technology in the spray nozzle design. Each individual nozzle consists of the following components (Fig. 3). Nozzle body Disc Spring Guide bushing Nut The fluid to be injected enters the nozzle body through tangentially drilled feed holes (A). This positioning results in a rotational movement of the fluid in the nozzle chamber (B). The spring (C) is selected for a certain set pressure. The spring material is an Incoloy grade, a material well suitable within the application range of the SLN-Temp. When the Δp between the injection fluid and the pressure in the main line exceeds this set pressure the disc (D) will lift from its seat. The small, circumferential, opening acts as a flow divider and the fluid will enter the main pipe in the form of a hollow cone. This is desirable as hollow cones are the best for quick conversion from fluid to vapor. The stroke of the disc is pre-set by the guide bushing (E), thus limiting the Kv value (flow coefficient). E C A B D Individual nozzles can be combined to form a nozzle head. The nozzle head is designed with a sequential opening of the individual nozzles such that a gradual increase in injection liquid is the result. Smooth control of the injection water quantity results in smooth temperature control of the desuperheated gas. Nozzle heads are calculated, selected and assembled on order specifications. Individual nozzles are not replaceable, but the nozzle head is a spare part in its entity. As all SLN-Temp valves will have an individual identification number, this number guarantees traceability. The minimum set pressure (disc opening) of the spring is 0,7 bar Δp The highest set pressure (disc opening) of the spring is 6 bar Δp. Fig. 3 Tyco reserves the right to change the contents without notice page 3

4 Codes and standards The SLN - Temp Desuperheater is designed and manufactured in acc. with ASME B Upon request it can be manufactured to meet a wide variety of other international codes and standards. Certified acceptance documents are available upon request. If special codes or standards are required by your local authority, then we would be pleased to discuss them. Multiple nozzle heads The SLN - Temp Desuperheater may be equipped with a variety of nozzle heads. The uniform body threading accepts spray cylinder heads with a wide range of Cv (Kv) values. Standard configurations are with either or 4 spray nozzles but special combinations are available. This feature enables the SLN - Temp Desuperheater to be customized to specific system requirements. Consult Narvik-Yarway or your local representative for details. SLN - Temp standard capacity range The Narvik-Yarway SLN-Temp has a basic selection from 4 sizes of nozzles. Sizing is performed using the data under ordering/sizing data (next page). Table 1 Nozzle designation Kv value Nozzle designation Kv value 12 AA BB CC AA BB CC AA BB AA BB CC DD EE Each individual nozzle can be equipped with a spring with settings ranging from 0,7 bar ΔP to 6 bar ΔP The minimum Kv value possible is 0,034. The maximum is limited only by the number of nozzles installed. This is selected by the Narvik-Yarway sales staff upon clients specification. Flow capacity limitations are: - Model 50 with a maximum water flow capacity of 25 m 3 /hr. in continuous service - Model 60 with a maximum water flow capacity of 50 m 3 /hr. in continuous service Definition S.G. Kv = Q ΔP Q = m 3 / hr. S.G. = kg/dm 3 Δp = bar hw Gw h1 Gst h2 Gst + Gw Fig. 4 Sizing formula Every desuperheating station is a mixing point where there is a heat and mass balance. The universal formula is: Gw = Gst ( h1-h2 ) : ( h2-hw ) This formula enables calculation of the quantity of water required to lower the inlet steam temperature to the set-point temperature of the outlet steam. In which: Gw Gst h1 h2 hw = Injection water mass = Inlet steam mass = Enthalpy of the inlet steam = Enthalpy of the outlet steam = Enthalpy of the injection water Tyco reserves the right to change the contents without notice page 4

5 Important system parameters Apart from the spray quality of the atomizer (primary atomization) there are other system parameters which influence the desuperheater stations performance. These are: Inlet Steam Velocity At high steam velocities, water droplets are easily disintegrated. This factor contributes to the overall atomization quality (secondary atomization). The minimum acceptable steam velocity varies as a function of the nozzle size and pipe diameter. In case of doubt, consult Narvik-Yarway. Water to Steam Ratio This ratio is determined by dividing Gw by Gst. For system steam pressures below 15 bar, this ratio should not exceed 15% for the normal operating conditions. Systems operating between 15 and 25 bar can have a ratio of up to 20%. For higher pressure duties, consult Narvik-Yarway. Distance to Sensor The distance from the injection point to the temperature sensor should be 12 to 15 meters. Systems operating at pressures above 25 bar can have significantly less run to the sensor, consult Narvik- Yarway. Required Straight Pipe Run The distance from injection point to the first pipe bend is also a function of steam pressure, temperature and nozzle size. Experience has shown that in systems up to 25 bar, 4 to 6 meters, is an acceptable distance. Note: For gas/fluid mixtures other than steam, different application limits apply. Consult factory. Ordering / sizing data Steam desuperheaters are selected specifically against application data. For optimal sizing, the following comprehensive data should always be supplied. Steam Data Inlet pressure Bar Inlet temperature C Outlet temperature C setpoint Steam flow max. t / hr Steam flow normal t / hr Steam flow min. t / hr It is essential not to over specify the required turndown ratio i.e.: Steam flow max. Steam flow min. This may have a negative effect on the controllability over the flow range. Water Data Water pressure Bar Water temperature C General Pipe size Pipe schedule mm Water flange position Steam line Steam flow Fig. 5 Spraywater must be injected with the direction of the steam flow. Flange bolt holes will straddle with main pipe centerline. Narvik-Yarway always recommends a strainer with a mesh size of approx. 100 μ (400 μ on request) in the water supply line to protect the SLN - Temp Desuperheater from clogging. Tyco reserves the right to change the contents without notice page 5

6 Table 2 - Standard materials Fig. 6 Item Name Material Equivalent Spray Nozzle assembly SS V.A. 5 Fastener ring SA182 F Mounting part SA105 C 22.8 SA182 F Body pipe SA106 Gr.B St III SA335 P Water flange SA105 C SA182 F Name plate SS SS 24 Steam flange SA105 C SA182 F Reducer A234 Gr. WP B St III Gr. WP Note Other materials are available upon request. Certification: SLN - Temp Desuperheater is approved by authorized authorities to comply with the requirements of ASME B / TRD 110. All data subject to changes Materials and data of units supplied, may deviate from this brochure. Please consult order documents in case of doubt. Recommended spares 8 5 Detail A 1 2 Detail A Tyco reserves the right to change the contents without notice page 6

7 Fig. 7 Water flange Table 4 C Table 3 - Dimensions (in mm) Model 50 Model 60 Qmax = 25 m 3 / hr. Qmax = 50 m 3 / hr. Standard length for steam line sizes up to 12" (DN 300) A B Option: standard length for steam line sizes 14" (DN 350) and higher A B C M min. 66,0 80,0 N 60,3 x 11,1 73,3 x 14,0 P 64,0 78,0 Steam Flange Table 4 Note Dimensions may be subject to change without prior notification. Narvik- Yarway will provide a certified dimensional drawing upon request. Table 4 - Flange connections Model 50 Model 60 M N A B Qmax = 25 m 3 / hr. Qmax = 50 m 3 / hr. Steam flange 3" class 150 4" class 150 class 300 class 300 class 600 class 600 class 900 class 900 class 1500 class 1500 DN80 - PN 25/40 DN100 - PN 25/40 PN 64 PN 64 PN 100 PN 100 PN 160 PN 160 PN 250 PN 250 Water flange 1-1 1/2 1 1/ Tack-weld or Circular-weld DN DN Pressure classes as per Pressure classes as per water data requirements water data requirements Minimum steam pipe size P 8 (DN 200) Consult factory for smaller sizes. Nozzles Tyco reserves the right to change the contents without notice page 7