SOLAR ENERGY SOLUTIONS
Examples of potential materials of construction ( MOC ) may include : Description MOC ( For 400 ° C ) MOC ( For 600 ° C )
Body |
WCB with Stellite . 21 Seat |
A or SA-351-CF8C , S50PWHT ( 347 SS |
|
|
Casting ), Stellite # 21 ( Seat Surface ) |
Disc A-182 Gr . F316 or A351 Gr . CF8M A-182 Gr . F 347H or A-351 Gr . CF8C Shaft A-182-F6a , Class 4 ( Forging ) Inconel 718 , ASTM B-637 , UNS N07718 Gasket Packing
Thermiculite TH 835 or Equivalent Thermiculite TH 894 or Equivalent
Globe control valve ( GCV )
• GCV designs also follow standards such as ASME B16.34 , API 623 , ASME Sec VIII Div . 1 etc .
• The design should prioritise preventing exposure of the packing area to hot flow to maintain the temperature within the admissible range in the stuffing box region .
• An essential consideration is the incorporation of a special packing system
Globe control valve ( GCV ) with an HT extended bonnet : i . For temperatures up to 400 ° C , materials like Garlock 1200 PBI , Garlock ThermaPUR 4122 and Zinc rings must be utilised . ii . For temperatures up to 600 ° C , the utilisation of Garlock Quickset 9001 1303 FEP packing materials is necessary .
Verification and validation
Thermal finite element analysis ( FEA ) Thermal FEA is essential for verifying valve designs . For cold salt valves , it helps identify and mitigate cold regions , while for hot salt valves , it assesses packing degradation and thermal loads . Transient thermo-structural analysis can determine thermal shock , fatigue life and creep life of valves , ensuring their reliability under CSP plant conditions .
Field validation
Testing valves under simulated CSP conditions , including thermal cycles and seal performance , provides critical insights into their real-world performance . Collaborating with industry partners and conducting onsite validation ensures design integrity and operational efficiency .
Energy saving and thermal loss in CSP plants :
Efficient heating and thermal management are vital in CSP plants . Key points include :
Steady state thermal analysis - TOBV
• Selecting heaters like tubular or ceramicbased ones optimises energy and geometry .
• Valves in cold salt lines are heated above salt ’ s melting point to prevent freezing , with external surfaces designed for insulation .
• Shaped heaters and precise sensor placement mitigate heat loss .
• Balancing power consumption and geometry maximizes efficiency , reducing costs and improving sustainability .
Developments and future outlook
Advancements in molten salt technologies are driving significant innovation in the valve industry , especially for Concentrated Solar Power ( CSP ) applications . These advancements demand valves capable of withstanding extreme temperatures , corrosive environments , and rigorous operational conditions .
Steady state thermal analysis - GCV Transient Thermal Analysis - GCV
32 Valve World October 2024 www . valve-world . net