Case Study: Utility Scale Concentrating Solar Plant

Steam technology is an important component in contemporary renewable energy systems like concentrating solar power (CSP) plants. In these plants, sunlight is focused onto a transfer fluid contained within a network of pipes or tubes—often molten salt. This transfer fluid then heats up and generates steam to drive turbines.

Abengoa's Khi Solar One plant in Upington, South Africa, is at the forefront of this technology. Spanning 300 hectares and boasting a capacity of 50MW when fully operational, Khi Solar One supplies enough clean energy to power around 45,000 South African households. However, molten salt has highly corrosive and erosive properties, which makes it challenging to control flow precisely and consistently over time. As a result, Abengoa chose to work with Trimteck for their process control solutions, based on our depth of experience in precision engineering.

What was the main challenge for Khi Solar One?

The plant engineers required control valves for the entire steam generation system, but they also had highly specialized applications beyond the capabilities of off-the-shelf products. To effectively maintain system uptime, these valves had to endure extreme conditions and resist frequent material degradation.

Abengoa needed control valves that could handle the high differentials in pressure typical in steam and condensate systems without cavitation damage. It also needed specially engineered valves for molten salt applications, which demand high resistance to temperatures, erosion, and corrosion.

What was Trimteck’s solution?

In response to Abengoa's unique requirements, Trimteck precision-engineered and manufactured a full suite of valves, all designed to operate flawlessly in the severe service conditions of a CSP plant. These included:

Steam vent valves

These control valves are vital for safely releasing excess steam to prevent pressure build-up that can compromise plant safety and efficiency. Trimteck's steam vent valves are designed to handle rapid changes in pressure, ensuring continuous operational safety.

Attemperator valves

Attemperator valves play an important role in controlling the steam temperature by injecting cooler water directly into the steam flow. Precision in this process is critical to maintain the steam at optimal temperatures for energy efficiency and to avoid thermal stress on the system. Trimteck's attemperator valves feature multi-stage trim technology to provide accurate temperature control and prevent cavitation, extending the life of the system.

Dump valves

In process control, dump valves quickly divert steam or fluids in emergency situations or during routine maintenance to ensure system stability and worker safety. Their reliability is essential, as it’s crucial that they don’t fail under sudden and extreme conditions.

We select appropriate materials for these valves, known for their durability and resilience. They are also equipped with features like multi-stage trim to combat cavitation and flashing — common issues in such high-stress environments.

In addition to this selection of valves, Trimteck's scope of supply for the Abengoa project also included:

• Main steam drain to continuous high-pressure (HP) drain tank: Ensuring safe and efficient disposal of condensate.
• Accumulator sampling and turbine bleed: Critical for system monitoring and pressure relief.
• Accumulator manifold drain to HP drain tank and cooling consumers to cooling tower: Important for operational stability and cooling efficiency.
• HP & low-pressure (LP) steam from auxiliary boiler: Facilitating steam control for auxiliary operations.

The result

Since its inauguration in 2012, Khi Solar One has set benchmarks in the CSP industry, becoming one of the largest plants of its kind globally. It was also the first to achieve 24-hour operation using only solar power. The successful implementation of Trimteck’s process control solutions was instrumental to these achievements, improving plant reliability and efficiency.

Premium control valves for efficient power generation

When your renewable energy operations require precise control in harsh environments, Trimteck is your trusted partner. We deliver advanced valve technologies specifically designed for CSP plants like Abengoa's Khi Solar One, ensuring compatibility with the corrosive properties of molten salt and the high differential pressures of steam systems.

Enhance your CSP project with Trimteck's specialized valve solutions, engineered to handle extreme conditions and ensure reliable operation. Contact us today to consult with a Trimteck engineer or use our AccuValve™ software for automated valve specification.