The SGS4 system has recently been upgraded in order to meet emerging market expectations for lowering the cost of energy for molten salt technologies. The new configuration reuses proven components with in a new arrangement, allowing it to maintain key operational benefits from the former design, such as fast start-up, guaranteed leakage-free operation and low maintenance requirements. The upgrade will help to achieve 10 percent reduction on technology capital expenditure and up to €4 million saving on auxiliary equipment, for two reasons.
First, the natural circulation in the evaporator unit eliminates the use of circulation pumps and the initial investment costs associated with it. Without the need to use circulation pumps, the electricity consumption and the risk for operational failures are greatly reduced.
Secondly, the components (evaporator, superheater, reheater, economiser) have been placed in an elevated layout, contributing to automatic venting and achieving easy draining as the molten salt flows by gravity alone. This means there is less need for venting and drain valves, thereby enabling the customers to save on supporting equipment that they would normally have to purchase. The reduced amount of valves also makes operation and maintenance of the plant easier, especially in typical cases, such as molten salt crystallisation, when cleaning of multiple valves becomes a costly burden.
In order to meet large-scale concentrated solar power (CSP) plants’ critical requirements for high availability, the optimised SGS4 system has been developed as a shell-and-tube type with header-and-coil equipment complying with ASME and TEMA standards. The most significant feature of the technology is that it allows the shell-and-tube design to have molten salt on the shell side of all components while maintaining the option to use natural circulation for optimal and stable operation.
The configuration also allows for smaller material thickness owing to an upgrade in the placement of tube bundles and pipes. This helps to increase cost-competitveness of the system itself. While the basic component design is the same as the previous editions, decrease in the material thickness reduces the weight of the equipment significantly, lowering the capital expenditure of the system by 10 percent.
Aalborg CSP will be attending the 9th International Concentrated Solar Thermal Power Summit (CSP Today 2015, Seville) on 11-12th November, where the company will introduce the latest developments, including the optimised SGS4.
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