The Cavity Receiver Project has the objective of increasing the understanding of thermal loss mechanisms and increasing the efficiencies of high temperature solar thermal receivers.
A ‘receiver’ is the device at the optical focal region of a solar concentrator (in this case, the ANU’s 500 m2 ‘SG4’ Big Dish). The role of the receiver is to convert focussed solar radiation into thermal energy (heat), which can be carried away by a heat transfer fluid (in this case, water/steam) for storage or further energy conversion downstream.
The dish features a two axis mechanism for tracking such that it can point directly at the sun throughout the day. The orientation of the receiver relative to the horizon changes throughout the day as the dish tracks the sun. However, the receiver remains in a constant position relative to the dish reflective surface, which means that the shape of the flux profile incident on the receiver is consistent, with the heat intensity changing in proportion to the incoming solar radiation.
The receiver features water / steam as the working fluid to match the existing ANU dish facilities. It is a once-through helically wound tube design. The new receiver is designed for peak steam condition values of up to:
- Receiver Inlet: 50°C, 160 bar
- Receiver Exit: 600°C, 150 bar
The forming of the pipe and tube was controlled with CNC rolling machines and checked using laser cut templates. The special geometry of the coil presented added complexity for assembly and welding. Every butt weld was radiographed, all attachment welds, LPI tested to ensure a quality product.
The compact steam generator coil was hydrotested to 35MPa for 60 minutes. The manufacture also involved the welding of several thermocouple tapping points to measure the temperature profile of the coil at working conditions.
This expansion / modernisation project involved a new design for a conveyor line to be used in underground mining. U-Neek supplied several hundred conveyor frames H and C types to make up about 7 kilometres of conveyor line. The frames were fabricated to Australian structural welding code AS1554 GP and galvanised after fabrication. Material thickness up 20mm.
This project involved manufacture of a critical process component for TiO2 production. The 150NB radiant helical coil was manufactured to exacting tolerances. Of notable mention as inconel material welding, hydrotesting & drying coil assembly to -12 degrees C dew point. Project time frame approx. 3 months.
Quenos at Altona, Victoria runs a polymerisation plant. The main process is a high severity ethylene pyrolysis furnace. Material used in the furnace is Incoloy alloy 803 (UNS S 350045). This alloy provides an exceptional level of high temperature corrosion resistance in oxidation, sulfidation and carburisation environments along with excellent stress - rupture strengths at elevated temperatures. The tubing internally finned to increase turbulence inside the tube and enhance heat transfer in the furnace tubes (dia 51 x 7mm). U-Neek manufactured all 8 banks of the furnace, complete with tube bending, critical welding of tubes to heaters, header flange welding, hydrotesting of equipment, complete NDT and MDR provided.
This project involved manufacture of almost all tubular pressure parts except furnace walls for 2 x 120MW boilers. Notable mention was dissimilar material welding, 1D bending of tubes, swaging and linishing of tube ends. Total tonnage was in excess of 200 tonnes. Project time frame approx 9 months.